CA1072725A - System for pollution suppression - Google Patents

Abstract

An apparatus for the treatment of purification of a fluid by treatment with a treating fluid in a flow pipe. The flow pipe has a flat plate orifice located therein, which orifice has an internal diameter of from about 0.7 to about 0.9 of the internal diameter of the pipe. A vena contracta portion is located in the flow pipe at a distance of from 0.25 to 0.5 pipe diameters downstream from said flat plate orifice. An injection nozzle for introducing the treating fluid into the flow pipe extends through the flat plate orifice with the tip of the injection nozzle being located treated by the treating fluid.

Description

~07'~7;Z5 BACKGROUND OF THE INVENTION
The present invention relates to a surge sup-pression system for preventing surge pressures or pipe hammer in liquid systems. More specifically, the present invention relates to the suppression of surge pressure or pipe hammer in liquid pumping processes.
Heretofore, various techniques have been utilized to 107'~7Z5 reduce surge pressures or pipe hammer in liquid systems where commonly a pump is employed. However, most of these techni-ques tend to be sophisticated, uneconomical, or impractical and furthermore do not greatly reduce the surge pressure in the system. One technique utilized a fly wheel to increase the inertia of the pump motor. Another technique was based upon the use of a stand pipe which may be either of a standard or the differential type. The latter type is more common as a means for protecting against under pressures which occur incident to flow regulation in penstocks of hydraulic turbines.
Another technique requires the provision of a storage tank or air vessel. A variation of this technique is a so-called one way storage tank, that is a storage tank equipped with a check valve which only permits flow during line under pressure or the like. A further variation of the storage tank technique is the utilization of a very large storage tank which may be a reservoir of water open to the earth's atmosphere.
The present invention also relates to the use of a scrubber for the general purification of a gas compound wherein the hydraulic radius of cylindrical media contained in the scrubber is equal to the hydraulic radius of the external flow ch~nnel. More specifically the present invention relates to a scrubber or washer wherein one or two stagesmay be utilized to thoroughly purify a gaseous compound through the use of high solubility fluids, oxidizing agents, or reducing agents.
Heretofore, scrubbers containing packed beds and the ,, .
; like have been utilized to effect fluid phase absorption.
Although the removal of an undesirable compound is effected, generally the efficiency of the process is degraded by -~07Z725 restrictions on hydraulic loading, aompromises between gas and liquid flow or excessive gas-phase system pressure drop. With respect to purification, fluids have been utilized which are not highly soluble. Moreover, solids such as activated carbon have been used and thus require periodical replenishment.
The present invention relates to the treatment or purification of a first fluid with a second fluid possibly a gas, with the first fluid under turbulent flow conditions in a flow conduit. More specifically, the present invention relates to the purification of a first fluid by a fluid (gas) in a flow conduit wherein turbulent flow exists to achieve thorough mixing or momentum transfer.
Heretofore, fluid phase treatment systems have been utilized in purifying fluids such as liquid of gases. In the purification of a gas by other gases, purification has largely been confined to contact chambers, packed beds and the like.
In such systems the treated fluid circulates through the cham-bers. The treating fluid achieves contact with the treated fluid in the packed bed. Where the active agent for treatment is a gas, it is dissolved in the treating liquid. Contact is achieved as before. However, direct contact is possible between a treating gas and a treated fluid. Although some purification i5 obtained, the amount is less than desirable.

The present invention relates to a synergistic two stage oxidative system for disinfection of materials. More specifically, it relates to a synergistic two stage disinfec-tion system utilizing a primary oxidizing agent in one stage and a secondary oxidizing agent in a second stage for the treatment of waste or sewage effluent.
Heretofore, in the field of disinfection, and prima-rily with respect to the treatment of waste or sewage effluent, oxidizing agents have been used to disinfect the effluent.
However, use of the various oxidizing agents even in combina-tion mainly gave a reduction in bacteria proportional to the amount used or to the amount of multiple compounds utilized.
Moreover, the treated effluent was usually very high in ammonia which itself exerted a high ~ n~ for secondary oxidizing agent or which required extensive further treatment to remove it from the system and prevent it from being discharged into streams or waterways where it possessed a highly toxic effect upon fish and marine life. Additionally, large scale removal of the ~ ; A by venting to the earth's atmosphere was often undesirable due to odors and pollution problems.
The invention relates to a system for the production of effluent from a waste treatment process containing low am-monia. More particularly, the invention relates to a system, as above, wherein the secondary treatment effluent is admitted to a nitrification tower through a special distributor, aerated according to a special process, filtered through media having a special hydraulic parameters and wherein the nitrification tower is insulated.

~C~7Z7'~5 Heretofore, various methods and procedures have been utilized to convert ammonia (NH3~ to ammonium nitrogen (NH4) in waste or sewage treatment plants. Although some of the various procedures have produced effluents with low am-monia, the processes are generally complex and costly, and do not operate consistently year-round.

SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a surge suppression system wherein a gas is inject:ed in-to a liquid at some point along a liquid flow system in an amount in excess of the gas saturation level of the liquid.
It is a further object of the present invention to provide a surge suppression system, as ahove, wherein the in-jection of the gas is at a high turbulence portion of flow of the liquid flow system.
It is a further object of the present invention to provide a surge suppression system, as above, wherein high turbulence causing devices are located within the liquid flow system coincident with the gas injecting points.
It is an additional object of the present invention to provide a surge suppression system, as above, wherein addi-tional turbulence causing devices are located downstream from the gas injection-turbulence causing devices.
It is still another object of the present invention to provide a surge suppression system, as above, which is particularly suitable for utilization in liquid transmission systems.

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~ ccording to the present invention, a surge suppres-sion system for dampening surge pressures comprises a force main or transmission line carrying a liquid, injection means for introducing a gas into said main or line, and the amount of said introduced gas being in excess of that required to saturate said liquid so as to dampen surge pressures.
It is therefore, an object of the present invention to provide a scrubber for the purification of a gas through the use of fluids having preferential and high solubility, possibly causing decomposition or containing catalysts to promote decomposition, or being heated to cause decomposition oxidizing agents or reducing agents.
It is another object of the present invention to pro-vide a scrubber for the purification of a gas wherein the scrubber contains conventional or specialized packing media, and the hydraulic radius of the external flow channel may be equal to the hydraulic radius of the internal flow channel.
It is a further object of the invention to provide a scrubber for purifying a gas wherein the scrubber has one or two stages.
It is an additional object of the present invention to provide a scrubber for the purification of a gas, as above, wherein the particular gas is ozone.

-Generally, the present invention relates to a process for the purification of a gas, comprising, adding the gas to an injecting mixing contacting region, a scrubber containing a packed bed, adding a fluid to the scrubber selected from the class consisting of solubility agents, 5 oxidizing agents and reducing agents, conveying said gas through said packed bed and exhausting said treated gas.
It is therefore an object of the present invention to provide a fluid phase treatmenl: system having a turbulence causing device to maxi-mum contact.
It is a further object of the present invention to provide a fluid phase treatment system, as above, having a downstream turbulence causing device.
It is a basic objective of the present invention to provide a fluid :. . , - treatment system with a treating gas-phase fluid wherein injection-mixing 15 and contact operations are operated under precisely controlled conditions o flow to maximize contact opportunity and to mi~imize the necessary ~ concentration of treating fluid (gas) required. The key to achieving these .~ ~ conditions is seen to be: to inject and mix so as to suppress the concentra-tion gradients in the axial and in the angular directions at a point where 20 intense radial mixing is induced by a turbulence-causing device and with a high concentration gradient in the radial direction owing to the coaxial in-jec~3n of treating fluid (gas) into the treated fluid (liquid or gas) ~\ ~,25 `; `
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lO~Z725 recognizing that this radial concentration gradient will be attenuated downstream of the injection point within a transi-tion length, the distance required to establich a stable velo-city profile in turbulent flow, 25 to 50 diameters, and pre-ferably at least 50 diameters, then to ensure suppression of any residual radial concentration gradient at the end of the transition length, a second turbulence causing device is introduced. This induces intense radial mixing, so suppressing ~ any~ L.- -;ning radial concentration gradient. Where said `~ 10 second turbulence-causing device is a flat plate orifice, a further feature comes into play. That is, the flat plate `;~ orifice is one of few, if not the only turbulence-causing devices which completely removes the lA ;nAr and turbulent boundary layer from the conduit wall mixing it into the main stream of treated fluid flow. From this device contact at maximum probability of contact between treating fluid and treated fluid may continue for a period dictated by reaction rates. Owing to suppression of concentration gradients and to the intense ;~;ng, the reaction rate will be -~i ;zed 20 minimizing the contact time and the concentration required for the treating fluid (gas).
Generally, the invention relates to a process for the treatment of a fluid by a treating fluid comprising, adding the fluid to a flow conduit such that the Reynolds --~er is at least 3,000, said flow conduit having a turbulence-causing ` ~ ::
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device, adding a treating fluid to said fluid channel and exhausting a treated fluid.
It is therefore, an object of the present invention to provide a two stage oxidative system for the disinfection of material containing a S distribution of ammonia and ammonium wherein a primary and a ;~
secondary oxidizing agent are utilized.
It is another object of the present invention to provide a two stage oxidative system for disinfection, as above, wherein the pH level of the material is lowered.
It is a further object of the present invention to provide a two stage oxidative system for disinfection, as above, wherein syner-gistic disinfection results are obtained.
It is an addltional object of the present invention to provide a two stage oxidative system for disinfection, as above, for the treatment of potable or treatment water, waste or sewage effluent.
It is stlll another object of the present invention to provide a two stage oxidative system for disinfection, as above, wherein the primary oxidizing agent is utilized in the first stage and the secondary oxidizing agent is utilizèd in the second stage.
It is a still further object of the present invention to provide a two stage oxidative system for disinfection, as above, in which the distribution of compounds of ammonia and ammonium is shifted to sub-stantially ammonium.

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The invention relates to a two stage oxidative procesh for disinfection of material containing a distribution of ammonia-ammonium compounds, comprising, adding a primary oxidizing agent to the material and adding a secondary oxidizing agent to obtain a very low bacteria count 5 where the ammonia-ammonium distribution i9 shifted toward ammonium.
, . , It is therefore yet anot er object of the invention to provide a system wherein ammonia in the secondary treatment effluent of a waste treatment-plant is readily oxidized to stable nitrates.
It is yet another object of this invention to produce an effluent lO in a waste treatment plant having low ammonia content through the ~-utilization of a distributor, an aeration apparatus and a packing bed having specific hydraulic parameters.
In general, the present invention pertains to a waste treatment systemfor low ammonia effluent comprising a nitrification tower, said 15 nitrification tower containing a packed bed, feeding secondary treatment e{fluent to said nitrification tower, said secondary treatment effluent aerated to contain dissolved oxygen, said oxygen added to said effluent through a small tube in a tubulent causing device.

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For a better underst~n~;ng of the invention refer-ence should be had to the acc ~ ying drawings wherein:
Fig. l is a block diagram, schematic illustration of the newly proposed system in total showing flow arrangements and the stages involved;
Fig. 2 is a plan view of an improved settling tank comprising one of the stages in the system;
Fig. 3 is a cross-sectional view of the settling tank of Fig. 2 taken on line 3-3 thereof;
Fig. 4 is a cross-sectional, schematic view of an improved trickling filter comprising a stage of the system of the invention;
Fig. 5 is a schematic flow diagram of the disinfec-tant unit indicating the operation under a hydraulic gradient with sensors and gas input control;
Fig. ~ is an enlarged cross-sectional view of one of the flat plate orifices associated with the disinfection unit of Fig. 5 ;nd;c~ting the gas input and sting relationship to the orifice to obtain -Y; efficiency in the introduc- -tion of the disinfecting gas and the elimination of concentra-tion gradients;
Fig. 7 is a flow diagram of a modified basic system illustrating system optimization and flow control; ~ `
Fig. 8 is a graphic illustration of the assumed in-fluent hydraulic and organic load;

~ , Fig. 9 is a graphic illustrati.,on o the optimum system process flow rates for Case A and a variable influent for Case B with constant process flow with a fixed effluent quality and fixed hydraulic/organic load;
; Fig. 10 is a graphic illustration of the flow load system optimization in Cases A, B and C defined in the speci-fication;
Fig. 11 is a graphic illustration of Case D also defined in the specification;
Fig. 12 is a cross-sectional end illustration of the tubular media which can be used in the trickling filter;
`~ Fig. 13 is an enlarged cross-sectional illustration of a short tube with injector to achieve good liquid-liquid, `~
or gas-liquid mixing characteristics; and Fig. 14 is a cross-sectional illustration of the trough which traverses the floor of the trickling filter ; showing how a suitable sedimentation agent may be inserted into the fluid flowing therein;
Fig. 15a is a cross-sectional view of an injection mixing elbow;
Fig. 15b is a cross-sectional view of a union con-taining an orifice;
Fig. 15c is a cross-sectional view of a flat plate ~ orifice;
; Fig. 16 is a sch~ -tic view of a two stage scrubber.
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1~7Z725 Fig. 17A is a cross-sectional view of a highly efficient fluid-fluid treatment system utilizing high turbulence-causing devices.
Fig. 17B is a schematic view showing a grid located in a portion of the fluid-fluid treatment system.
Fig. 18 is a graph setting forth the relationship between temperatures, pH and the equilibrium between ammonium and ~ -r;a.
Fig. 19 is a cross-sectional view of a nozzle.
Fig. 20 is a plan view of a large diameter distri-bution arm and its rotating support post;
Fig. 21 is a front elevational view of the distri-bution arm of Fig. 20;
Fig. 22 is a plan view of the arm alone indicating some of the internal structure in dotted lines;
Fig. 23 is an elevational view of the arm of Fig. 22;
Fig. 24 is a broken away enlarged view of the nozzle arrangement taken from the circled area of Fig. 23;
Fig. 25 is an enlarged cross-sectional view taken on line 25-25 of Fig. 22;
Fig. 26 is a modified double flow channel similar to that shown in cross-sectional configuration of Fig. 25;
Fig. 27 is an enlarged cross-sectional view to show the flow path in the distribution head to define the double flow channel of Fig. 26;

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Fig. 28 is an enlarged elevational view of the dif-fusing nozzle utilized in the distributor arm of Fig~. 20 -23;
Fig. 29 is a side elevational view of an alternative sweep elbow that might replace the diffusing nozzle of Fig. 28;
Fig. 29A is an end elevation of the sweep elbow of Fig. 29 indicating a flattened end outboard;
Fig. 30 is a graph illustrating optimum concentra-tions of polyelectrolyte feed for -~i removal of suspended matter;
Fig. 31 is a plan view of a contact tank incorpora-ting the preferred injection mixing system of the invention;
Fig. 32 is a cross-sectional view of the tank of Fig.
31 shortened in length, taken on line 32-32 of Fig. 31;
Fig. 33 is a partial cross-sectional view of the contact tank taken on line 33-33 of Fig. 31;
Fig. 34 is an enlarged broken away view of the injec-tion mixing elbow utilized in the tank of Fig. 31; and Fig. 35 is a schematic illustration of an activated sludge air injection system for an activated sludge system.

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-15a-DEFINITION OF TERMS PSEUDOMONAS, ALCALIGENES, - FLAVOBACTERIUM, MICROCOCCUS AND ENTEROBACTERIACEAE
ACTIVATED SLUDGE
All types of bacteria make up activated sludge, however, in 5 usual operation obligate anaerobes will attenuate in number in response to the presence of air. A proteinaceous waste will favor alcallgenes, flavo bacterium and bacillus. A carbohydrate waste will proliferate pseudomo-nas as well.
ANAEROBIC DIGESTERS ;~
The anerobic digester bacteria include facultative and obligate anaerobes in active metabolism. Dormant aerobic forms may be present, such as spores of fungi. Acid formers are predominantly facul- -tative forms although a few obligate anaerobes have metabolic end products which are acid. ~
Methane formers are obligate anaerobes, methanobacterium, methanosarcina and methanococcus in the metabolic pathway to subse-quent end products where methane is a precursor, the pathway can be intersected owing to the implied vulnerability of methane formers to oxygen, oxygen-ozone or air. Thus, selective disinfection provides a , ~ .
20 means to inhibit methane formation or to deny a metabolic pathway to succeeding end products where methane is the necessary precursor. With denial of a pathway, an alternative pathway may be stimulated by changing environmental conditions such as an aerobic activity. In this way, methane ~`
would not be formed. The SQurCe material, carbon dioxide would not be ~5 reduced. This is an unnecessary step in waste treatment, since carbon dioxide is a stable end product of aerobic treatment. The hydrogen ~, , ~, .
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~072725 involved vould not be acted upon. It i8 probably a con6tituent of formic or acetic acid. Thus, the alternative metabolic pathway opened i8 that for aerobic microbiological decompo6ition of acetic acid. In6tead of the anaerobic sequence acetic acid, acetoacetic acid to acetone acid isopro-panol or to butyric acid and butanol, this invention develop6 the aerobic sequence. It is: acetic acid, pos6ible pyruvic acid, oxalacetate, citrate ~; and the citric acid ~Krebs) cycle to terminal oxidation.
;~ In a similar way, the anaerobic reduction of sulfate6 by the ; obligate anaerobic, desulfovibrio can be inhibited. Shifting to an aerobic lO environment denies a pathway to hydrogen sulfide. It has been found that this is readily achieved practically by aeration. Consequences include a marked reduction in objectionable odor and long persistence of aerobic action. The latter case is demonstrable by unexpectedly deferred methy-lene blue stability tests indicating a shift to products of anaerobic meta-1 5 bolism MICROORGANISMS IN WASTE TREATMENT
- Trickling Filter. Filter microorganisms reflect the faculta-tive nature of the filter. Predominant are bacteria; aerobic, faculta-`~"' : -tive and anaerobic. Obligate aerobic spore formers bacillus are easily 20 found in-the upper, aerobic plaques. The obligate anaerobe, desulfovi-brio can be found in lower levels at the plaque-stone interface where, in usual practice, DO is zero. The majority of bacteria are facultative, living aerobically until DO zeros, then anaerobically.
With reference to the drawings, Fig. 1 illustrates the waste 25 treatment equipment, proces6 and overall sy6tem of unit operations in which the invention operates . A primary sedimentation tank is indicated by :

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numeral lO. The tank 10 receives comminuted raw wa~te including settleable solids from a line 12 issuing from a main line 14. A multi-plicity of such lines 12 and subsequent operations may exist.
Two other flows are introduced from the operations which follow, 5 constituting feedback of digester supernatant line 12a and of primary recirculation line 12b. The supernatant fraction i9 waste having high organic loading, relatively low flow, and it is resistant to aerobic pro-cessing for two reasons. First, it presents a biotal population adapted to anaerobic digestion and second, its organic composition includes the pro-10 ducts of anaerobic metabolism.
The second fraction of flow is the primary recirculation usuallyoccurring at rates in the range of one half to three times the raw waste rate.. The recirculation flow is characterized by low organic loading and a high degree of treatability in an aerobic process. It exerts dilution 15 effects on the raw waste which are not only marked, but which may be used - in conjunction with secondary recirculation to great advantage in smoothing hydraulic and organic loading, as discussed later.
These three flows are impressed upon primary sedimentation.
Regulatory authorities often stipulate hydraulic design criteria for sedi-20 mentation equipment m terms of the tank ovérflow rate which prevails for `: the composite flow. Such overflow rates may be affected by the technique illustrated in Fig. 1 of intercepting a portion of flow to be fed forward to bioprocessing indicated by nurneral 16. As discussed later, in ættling, using feed forward techniques, additional benefits accrue for example in 25 organic load smoothing.
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~07Z725 The basic flow from primary sedimentation 10 proceeds to a primary stage of bioprocessing 16. A roughing trickling filter is illus-trative. There, to the sedimented basic flow, three component flows may be added. One 18 is the feed forward intercept flow noted previously. The 5 second 20 is the bypassing fraction of primary recirculation. The third 22 is the secondary recirculation shown in Fig. 1. The existence of the feed-back flows, the feedforward flow and the basic influent flow prior to bio-processing is important. This combination provides sufficient degrees of freedom to enable independent regulation in this and succeeding operations 10 of hydraulic and organic loading with some flexibility and without over-loading primary sedimentation. From the bioprocessing operation 16, such as the roughing filter shown, in most cases, existing plant flow proceeds to secondary sedimentation 24. In some instances, a second stage of bio-processing 26 may be present. Usually this would be ~ finishing trickling 15 - filter. Rarely, but preferably, it would be an activated sludge stage of bioprocessing .
In this instance, as shown in Fig. 1, from the first stage of bioprocessing 16, the flow is split, with primary recirculation over line 12b withdrawing a fraction for feedback to an earlier stage of processing 20 10. The remaining fraction proceeds to the second stage of bioprocessing 26. Before introduction to bioprocessing 26, such as to the activated sludge operation, it may be mixed with recirculaling activated s ludge from line 28.
A remaining portion of the recirculating activated sludge, is 25 discharged for digestion with the primary sedimentation tank sludge in a primary digester 30 and secondary digester 32.

From the activated sludge operation 26, the flow proceeds to secondary sedimentation 24. The regulatory authorities stipulation on overflow rate again prevails; however, the permissible overflow rate for secondaries 24 may differ for those from primaries and may further depend upon the type of bioprocessing operation involved. The activated sludge operation is characterized by highrates of recirculation over line 22 of sedimented s ludge as suggested in Fig. 1.
From the secondary sedimentation operation 24, flow may be intercepted for feedback recirculation over line 22 after partial sedi-mentation. A second fraction of fully sedimented flow may be returned in the baslc secondary recirculation by line 34. The remaining fully sedi-mented flow proceeds to disinfection over line 36. In the disinfection unit 38 operation, in-line gas-liquid disinfection over line 40 by injection may procede the conventional contact chamber disinfection. The techni-que of gas injection is more fully defined hereinafter. The same, or complementary disi~fectants may be used. For example, in-line ozona-tion might be followed by contact chamber chlorination in unit 38.
Alternatively, chlorination may occur in both stages or only in the contact chamber with no in-line disinfection. Disinfection yields the final effluent over line 42.
It has been shown in Fig. 1 that sludge is removed from waste at successive stages of waste treatment. The sludge is stabilized, usually in two-stage anaerobic digesters 30 and 32. From the digester 32, sta-bilized sludge may be discharged to drying on beds, in a kiln, fluidized bed reactor or on a vacuum dewatering drum. Ultimate disposition of solids products may be land fill or incineration. Disposition of digester supernatant over line 12a has been noted previously. It is this overall . . .

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framework of unit operations within which the concepts pr~poffed by the invention must be implemented. Dir3cussion will now proceed in terms of each of the unit operations described. A final section will deal with optimum systems integration. L
- It should be noted however that aeration or other injections may take place at a considerable number of other points into the effluent in the system of Fig. 1. Specifically air may be injected into the digester supernatant recirculation, the raw waste input, the effluent from disinfection tank 38 and to the effluent from the secondary bio- ' -processing tank 26. In some instances it is desirable to inject a chlorine water solution into the effluent before disinfection to obtain point chlorina-tion. It should further be understood, of course, that chlorination may be used in the disinfection tank 38.
SE T T LING
Settling or sedimentation is a standard unit operation in waste treatment. The effectiveness of this operation is essential because of the high concentration and broad size range of the particles present in sewage.
The concentration of these particles falls in a size classification from a diameter of 0. 000001 to 5. 0 millimeters. This is an important character-istic, since it affects the settling velocities upon which sedimentation or clarification depend. The significant velocities range upwards from a lower limit of 10 9 millimeters per second. These velocities are achieved in clarification or settling in sewage treatment and are of primary interest owing to their broad range and extremely low magnitude.
2S The importance of this from a practical standpaint is in the degree of momentum exchange, vorticity, or of turbulence which will .

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degrade settling or clarification processes. Obviously, it is any level of velocity which approaches the settling velocitie~ de~cribed. The ~ig-nificant implication of this, of course, is in the fact that the kinetic energy which is present at the influent to the sedimentation chamber 5 should be reduced to the lowest pos~ible practical level. Anything which tends to increase the kinetic energy of the influent jet will degrade the performance of the clarification or sedimentation process. Recircu-lation has such effects, however, it has offsetting compensatory ad-vantages in diluting the organic load to be handled. In contrast, high l0 velocity, Or excessive momenturn exchange impose a penalty without an offsetting advantage.
` For an understanding of the basic construction of the settling tanks l0 and 24, reference should be had to Figs. 2 and 3 of the drawings.
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The specific effects of the modifications of the settling chamber are as - 1 5 follows:
-~ a) To control the fluid path prior to free settling.

b) To reduce the velocity and turbulence level at the it~fluent to the region of free settling.
c) To increase the settling flow path length and the time available for settling.
, d) To increase the functional effectiveness of s e ttling .

e) To reduce, by forward-feed tèchniques, the -~ hydraulic load on the settling tank and particularly to reduce its overflow rate.

f) To introduce a further degree of freedom in hydraulic - and organic load existing in present feedback recir-culation .
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The apparatus making up the improved settling tank of the invention may be fitted in a con~rentional circular ~ettling tank. Its distinquishing element i8 a rotationally-transformed radial or hyper-boloidal-envelope diffuser. The diffuser may incorporate spiral vanes L
indicated generally by numeral 60a. The rotational transformation is through 7 or less to ensure minimum probability of flow separation at the channel boundary. This is a critical factor in the three-dimensional diffuser design owing to the flow deceleration which is induced.
Smaller, buttsimilar, three-dimensional spiral-shaped collectors 62 and 64 may be used at one or more centrally located annular collection -points to provide upper effluent collection and/or intermediate effluent ~ !
collection, respectively. There, flow is accelerating and boundary layer separation is much less significant.
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In a conventional sedimentation tank, influent and effluent flow may be distinquished. Previously and in existing art, these have not been considered in terms of optimum overall circulation. The case i~ illus-: ~ ~ trated by the conventional circular plan view sedimentation tank. In it, flow is usually upward in a central influent well. At the upper limit of this central well, flow is predomin~ntly radially outward with both rela-tively high turbulence and velocity.
In such a tank, the predominantly radially directed surface jet induces a circulation in the central region. In consequence, a sus-tained toroidal vortex circulation develops there. This means that the intended settling flow is perturbed. It is degraded functionally by rota- ,`
tional mixing usually imposed mechanically and gravitationally by earth rotation. The result is settling circulation.

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10~7Z7Z5 Concurrently, the outflow i9 predominantly a peripheral, radial flow. It induces a similar toroidal vortex at the overflow weir.
This toroid exhibits comparably lower velocities, lower turbulence and a much larger diameter This circulation is of lower energy level corres-5 ponding to the reduced overflow velocity. The direction, or sense ofrotation, in the second toroidal vortex is the same as in thc influent circulation. This means that at an intermediate radial position in the tank, the two toroidal vortices interact with opposing local vertical components of flow. This interaction manifests itself by momentum exchange which 10 degrades settling.
To attempt sedimentation under imposed conditions antagonistic ~ .
to the functional objective seems ill advised. A desirable situation is to recognize that an overall circulation must be considered and that the direct and induced flow described must be complentary to the necessary 15 circulation. This is the general objective of the settling tank of the inven-~ tion.

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This ls possible under the case for circular plan view sedimen-tation if a single toroidal vortex may be induced under controlled condi-tions of overall circulation. Preferably, this should be done in such a way as to enhance the primary sedimentation flow and, if neces~ary, to yield a secondary effluent having predictable sedimentation.
This may be accomplished by insertion and use of the central collector 62 described, positioned beneath the central influent jet 82.
Its flow is radially inward below the influent jet boundary surface. Owing to the presence of an hyperboloidal diffuser surface or vane 60a, the central effluent can operate with minimum degradation of the influent jet.
¦~ Moreover, it operateæ upon a well-sedimented, low turbulence fraction of sedimentation tank contents. These conditions lend themselves to the production of a consistent, predictable fraction of partially sedimented flow which reduces the tank overflow ratè.
On the inlet to the intermediate level collector in the sedimen-tation tanks it may have the hyperboloidal profile of the upper diffuser vane 60a since it is less critical in that flow is accelerating. On the system ~; optimisation, more fully explained hereinafter, it appears that it is essential to control the process, operated manually or automatically to accomplish the desired flows stated above. Representative means 70 for manual or' ;~ ; automatic regulation are provided. Implementation of sensors 72 for ~
flow are an obvious requirement. One ~L y to determire organic load i8 to measure it by lab techniques on typical days. The average hourly results could be charted. Control of means 70 could be based on the expectation that this would occur. It is also possible to use inferential measurements of load, such as those based on light transmission or spectral ab-sorption in narrow bands of wave length.

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Probably rapid, intense oxidation could be accelerated suffi-ciently to give real time data on BOD.
Then, system control for manual or for automatic con-ditions may be based on an expected program (historical find-ings) modified by real time measurements of the actual hydraulic and organic loading conditions with sensors 72, for example.
This is a standard control technique in any servo system. The essential feature is to program, establish errors, impose an error correction and instrument the result to make sure the error was corrected. If not, a secondary correction may be introduced.
FLOTATION SEPARATION
This concept may be introduced with a secondary func-tional effect of the central influent well 90. The affect is applicable where flotation, particularly for oil and grease sepa-ration is of concern. These conditions occur in primary sedi-mentation. To accomplish this result, presaturation of the influent with air as through injector 92 at pressure levels ex-ceeding that at discharge is desirable. Outgassing of the excess air as the system is depressurized enables enhAnced flotation in the influent well 90 of the primary sedimentation tank. This - integrates equipment and methods of se~i ~ntation improvement with those of gas-li~uid mixing, both as set forth in the present invention.
The collectors 62 and 64 remove two cuts of flow from the settling tank and from the sedimentation effluent discharges from the overflow weir central collectors. The upper cut is taken from 6 inches to 30 inches below the liquid line which normally runs closely adjacent the top edge of the tank. The lower cut is taken from 36 to 48 inches below such li~uid line.
The major portion of intercepted flow amounting to approximately

2/3 the total is taken from the upper effluent collector 62.
The lower collector 64 removes the remaining flow except for : ~ ~ 107Z7ZS

sludge and its entrained liquid. Normally, it will be nece~sary for the effluent picked up by collector 64 to pass to another processing operation for further treatment. From the sedimenta-tion operation, the basic flow sheet leads to bioprocessing.
The effluent flow in the seA; ~ntation tank is indicated by the arrows~94. The effluent enters line 66 through valve 70, up ~;
the influent well 90, driven by pump 68, and discharged from the top 91 of well 90, through s¢reen 74 and into a spiral discharge by vanes 60a adjacent the top surface of the effluent level.
The diffuser vanes 60a are driven in a slow rotary motion by :
motor 110 which is supported on a bridge truss 112 which extends ; over tho top of the tank. The motor 110 is of variable speed and~appropriately driven for the correct latitude of the tank since the vortex for the effluent actually ~p~n~ on latitude. ~-Flow is controlled by valves 82a and 84a, as best een in:Fig. 2 of the drawings, and at the inlet by valve 70.
The effect of the valves in inducing turbulence at the diffuser ffluent~ls suppressed by means of the hole size in the screens 73 and~;~74. It should be undelstood, how_ver, that similar oper-ZO~ations~oacur at greatly reduce~ velocities in tank 24 which 6;~ ~ might cause the elimination of an upper effluent collector 64.
At the end of the vanes of diffuser 60a, the effluent : :
is di~rected~in close to a ~ng~ntial direction in the horizontal plane. The vertical component of velocity is extremely low owing to deceleration in the diffuser. In view of the low velo-city, it is clear that sedimentation will occur in the diffuser.
Provision is made for continuous sludge removal. This is done by operating the diffu8er at close to zero buoyancy, a mec~an technigue readily within the skill of one knowledgable in the art.

The diffuser vane 60a is rotated a very slow speed, ` perhaps one revolution per hour. These serve as collectors of finely classified material. The sludge is L~ ed through pipe ::

~ ,"~

0~ 5 , ` 93 in the central section and out through the'tank bottom, as well as through a sludge trough 95 and sludge conduit (not shown) 94.
It has been anticipated that the extreme care taken in settling tank design may be upset by two factors. One is wind induced surface cooling and super; asod horizontal flow.
The seco~ is the`density AnAl- ~ in water which occurs at 4C.
The latter Pactor may have severe c~nsequences in terms of ver-tlcal ci~culation. In addition, there is the usual effect of 10 temperature variation on the`density of water. For these rea-sons, the invention uses an air enalosure over the tank, as in~ic~ted by cover 102. This cover 102 mitigates the effects of wind and temperature.
At least one of the central effluent volutes 82 or 84 wlll~be~vertically adjustable, and probably both, so as to en- -sure~positioning thereof in accordance with the flow de nAR
through~the~tank to achieve optimum performance.
To ensure light gravitational loading, the rotating d`~user 80~will be~supported peripherally at each sector by -20 ~ el'`~8Ob r11nning ~at fix d load on the bottom. The wheel load aontrol may be set with~a suitable type of 8pring loaded ~ ch~rs.
; The seConAAry 8ettling tank 26 receives effluent from the lower cut of the first tank 10. Its primary sed; rntation in its diffuser will pass particulates of 200 mesh or finer in-to~the~tank proper. The~de-crLbed cut for particulates greater in size than those passing a 200 mesh screen will be deposited and L~ ved~from the seA' intation which occurs in the diffuser 80 beneath the false bottom, as in the flow path 78.
In regard to flow, in the gecon~ry settling tank 26, the hydraulic effluent i9 one-third the plant effluent. The tank proper i8 lnt~nA~d to separate, in two cuts, the coarsest effluent particles to those of less than .....................

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~ . ~. . . ...... . . . .

f ~ 107Z725 ~r ~

200 mesh. In the upper cut of sedimented flow, two-thirds the effluent is removed. The lower cut of flow removes one-third the tank effluent, or about one-ninth of the initially impressed hydraulic load on the plant. Only this fraction 5 of flow proceeds to the trickIing filter or other BOD reduc-tion process.

~O~ G
T~ICKLI~G ~;ILTE~
The following discussion will involve the opera-tion of the first bioprocessing stage, a roughin~ filter 36 C~ only known as a trickling filter. No discussion will be given to the aeration stage 34 impressed upon the influent, as this is covered in my U. S. Patent No. 3,853,764. Bio-processing operations are responsible for the principal reduction in BOD.
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. .
The elementary theory of a trickling filter is than an extended surface is provided usually using rock fill, about 6 feet deep, on which a microbial plaque develops under pulsed film flow of waste liquor containing some dissolved oxygen, DO. The plaque is comprised of a surface-contacting anaerobic substrate immediately adjacent to which anaerobic and facultative micro-biological forms predr ;nAte. Above this layer, aerobic forms may be present. This implies a source of oxygen. Ostensibly, this is provided by an induced, vertical, natural-convective air circulation occurring parallel or countercurrent to the pulsed liquid flow.
~ A f1lnfl~--ntal limitation of conventional trickling ; filtration is the indifferent oxygenation occurring therein.
In consequence, aerobic processes essential to bioprocessing are inhibited. Diminished capacity in organic load reduction results. A further limitation aggravates this problem. It arises since, to allow some air circulation, hydraulic loading is restricted. This reduces the capacity of the filter and -~ concurrently the effectiveness of waste treatment. This is so because the hydraulic compromise restricts flow recirculation to the filter, a prime factor in deriving significant BOD
reduction.
To indicate the deficiencies of free convective air flow in trickling filters, it is of interest to refer to opera-ting conditions inducing such flow. A basic equation for air velocity as taken from Waste Water & Waste Water Engineering, Fair, et al, John Wiley & Sons, Vol 2, pp 35-13, is:
V a - 0.135 ~T - 0.46 where V a is the air velocity in feet per minute and, ~ T is the temperature difference between the air and the waste water, F.

.
, ~ ~0'7~'7~5 The waste water-air temperature difference seldom exceeds 25F. For temperature differences of 10, 3.4F, for example, V a is respectively +1.0, 0 and -1.0 fpm. The po~i-tive sign denotes downward flow. Recognizing the filter is a stone-packed bed about six feet deep, in no case is a realistic air velocity indicated. Forced air circulation has been ~ n~ with little promise. Packed bed resistance to air flow can be high especially with superimposed hydraulic flows.
The limitations of aeration and compromises in hydrau-lic~ loading are unnecessary. The ideal remedy is use of an effective air-liquid mixing system in the trickling filter in-fluent line. This will provide DO in the range of 7 to 8 ppm, ; all year round and a* any hydraulic loading. The particularly undesirable restriction of recirculation may be rel~xe~. This simple remedy will ~nAhle hydraulic loading in the range from ~;
l,OOO~to 3,000 or more g~llon.c per square foot per day. Typi-cal current practiae is at about one-fifth to the lower range of thece levels. The hydraulic~flows are restricted to these 20~levels to~defer block;ng of air flow which has been necessary to provide for aeration. Having eliminated compromises dic-tated by i~dequaaie~ of aeration in conventional art a simple ~ `
change enAhlec full exploitation of the revised trickling fil-ter process. This change is one of media, from a size range of coarse rock to a re~uce~ size range of smaller media. The chAnge in medla is primarily responsive to hydrodynamic flow.
` This is so because compromises relating to one flow are unne-cessary. TnA~ ch as the change is in hydrodynamic character- -`
istics, it is conventional to describe the desired media pro-perties in terms of hydrodynamic parameters.
The parameters of interest are the friction factor, the Reynolds number and the roughness coefficient. The media size factor applies as an equivalent diameter. The .

.

/

;` 10727Z5 characteristic length of flow path is the bed depth, which is conventional. The relation among these factors i8 of the form:
f = N +b where f is the friction factor a is a constant NR is the Reynolds number and b is the bed media roughness factor.
The definin~ equat~ons of interest are: ;
f = 2g D~V 2~P , and NR = De Vu It suffices to define the media in terms of its equivalent di-, ~ . .
ameter and roughness factor. Flow conditions are stipulated by the functional relationship between friction factor and Reynolds . ~ ~
number.
The typical parameters for new media are in the range tabulated next for a hydrodynamic or hydrofoil elements. This àrises in relation to an influent waste with high DO and no aer-. :
ation required in the filter proper.
I have calculated a substitute plastic media, for example PVC. The media is extruded tubing. It is assembled in an equilateral triangular grid to -~i ize the surface installed per unit volume. ;`
The tubes are spaced to ensure balancodflow ; nSi d~ the , ~ ~
~ vertically positioned tubes and outside the tubes. ThiS requires ~ `:
~ that the hydraulic radius for the internal and external passage :
be equal.
~: A typical result appears as follows: ' OD = .84 inch ID = .74 inch L = Grid spacing 1.16 inch The hydraulic radius of a ch~nnel iS:
Area of section/perimeter The section described above exhibits an area for biological ...............................................

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-31a-` ~ 107Z7ZS

plaques of about 40 ft2 /ft3. Conventional rock has less than 40% of ` this specific surace.
The lengths may be ull depth in a continuous section, from 6' to 30'; however, shorter lengths stacked to the total depth have advantage~.
S The basic advantage is that the laminar boundry layer of liquid on the microbial plaque starts at zero thickness and builds up. A length in the flow direction which is short compared to the length required to fully develop a stable l~n~inAr boundry layer keep~ the dissolved oxygen supply to the plaque readily available. The diffusion gradient i8 increased in two ways. First the concentration is 6ustained at high levels, second the boundry layer thicknes6 is decreased.
The length for a fùlly developed boundry layer in laminar flow is as great as twenty feet for water flowing in tubes of about 3/4 inch diameter in the limiting transitional range of Reynolds number, about

3, 000. Expressing distance in terms of diameter, the transition length i8 about 1/10 to 1/20 the Reynolds number.
The flow in the spaced tubular media at the limiting laminar Reynolds number may be estimated. It is 22 million gallons/day per 1000 square feet of media surface. Hydraulic loading rates are conventionally less than l million gallons/day per lOOQ square feet. Thus, planned high hydraulic loading is feasible with this media.
' ~ Moreover, the uncompromised rates enable much higher organic loading. Instead of present upper limits of less than 70 pounds of BOD per day on each thousand cubic feet of media, three to four times thi~
25 load appears feasible. The high organic or nitrogenous loading only be-comes practicable with preaeration which permits much higher hydraulic , ' .

~` ' '~ , , . .

.

loading. All th~ee variables, DO, hydraulic loading and organic loading, interact. Because of this, only a mutually compatible ~olution is feasible. In this instance the equipment and method involved bring into action the integrated benefit of efficieng gaR-liquid exchange and bio-5 processing operations.
The structural details of the improved trickling filter utilizing a 134 media described hereinbefore are illustrated in Fig. 4 of the - drawings which shows that a circularly-shaped housihg 120 centrally mounts a carrying post 122 which receives the liquid effluent through pipe 10 124 carrying the aerated effluent discharge from the settling tanks. The post 122 rotatably carries a distributor arm 126 which is rotatably driven hydraulically by reaction or by a motor 128 connected thereto through shaft 130 and double flanged coupling 132. The liquid influent through pipe 124 passes up through center post 122 and actually distributes in a: . --15 sprinkled relationship out the distributor arm as it is rotated by motor . ~ :
, 128, all in subst~ntip~1ly the conventional manner heretobefore utilized : ~ ~
~; ~- in trickling filters.
- ~
In the particular construction utilized, some type of wire mesh to forma large circular bed indicated generally by numeral 134 20 is filled with loosely packed stones or the specialized materials defined above that offer promose of providing greater surface ranges per unit `~ volume. As long as the problems of plugged liquid flow and undue gas-.~ ~ phase flow restrictions are considered, extended surface packing can be ~: :
used effectively in this configuration. In any event, the liquid sent out by distributor arm 126 drips down through the packed beds 134 into the open base.
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`` 10727ZS
!
In addition the invention may contemplate utilizing a plurality of forced air blowers, each indicated generally by numeral 140 positioned around the periphery of the tank 120 and adapted to drive air in the dir-ection indicated by the arrows 142~ Since one of the purpo~es of ~uch a 5 trickling filter to reduce BOD i8 to insure more oxygen is present to cause oxidation of the liquid effluent, such forced air which must neces~
sarily pass through the bed in a reverse flow to the liquid flow therethrough, forced circulation can supply oxygen to sustain aerobic metabolism.
Further, in order to provide the increased oxygen atmosphere, excess 10 oxygen i8 actually injected into the effluent through pipe 144 into some type of turbulent mixing chamber 148, as appropriately controlled through vaive 146. Also, in order to make the filter operate on nearly 100%
humidity in the atmosphere, some type of roof covering indicated gen-erally by numeral 150 may be provided that is supported by a catenary 15~ cable arrangement 152. Hence, the trickling filter may utilize lOO~o `; ; ~ relative h~=nidity, forced air circulation, and ah oxygen enriched atmos-phere because of the oxygen injection into the effluent. The increase in plant capacity and reduction in BOD is readily measurable with this setup.
ln this aerobic process it is also apparent that the design - 20 features describèd for improved sedimentation means may enhance the , -treatment system overaIl. In other words, oxygen injection into the sludge digestion unit 22 is contemplated 80 a~ to greatly enhance the operating capabilities of that unit to produce saf`e sludge concentrations.
The invention might also incorporate the addition of excess 25 oxygen directly into the humidifed atmosphere through a pipe 1~0 as controlled by valve 162. The control of the amount of oxygen entering .
: -34 -~` ~ 107Z72S

might be appropriately provided by a suitable sensor 164 a~sociated with the effluent output pipe 138 and operating in conjunction with a rate of flow instrument indicated by block 166, and an oxygen concentration unit indicated by block 168. Appropriate sensors 164a-d are associated with - 5 the rate of flow instrument 166 and oxygen concentration unit 168 to ; ~ complete this setup, so as to control the actual amount of oxygen flow through pipe 160 for the most economical operation of the system.
BIOPROCESSING SECOND STAGE ACTIVATED SLUDGE
An activated sludge operation may be the sole bioprocessing lO unit or a secondary èlement in a two-stage bioprocessing operation. It is unlikely to find actlvated sludge as the initial element of a two-stage bioprocessing operation. This is in recognition of the sensitivity of activated sludge operations to fluctuating influent hydraulic or organic - loads. Although not present typical practice, activated sludge operations lS may be adapted to handle fluctuating hydraulic and organic plant jnfluent . ~ .
loads. This may be done by providing sufficient flexibility in circulation to accomodate independent balancing of hydraulic and organic load in-cident upon the activated sludge operation. Thls has been referred to before and will be discussed under system integration.

Regardless of the mode of application of the activated sludge operation, a predictable requirement exists for aeration~ Observed :.
aeration corresponds to from 500 to 700 cubic feet of air per pound of BOD removed. The implied oxygen requirement is from 7. 5 to 10~ 5 pounds of oxygen per pound of BOD removed. An equivalent q~uantity is derived from surface aeration. Thus, the overall conventional requirement for oxygen is froml5 to 21 pounds of oxygen per pound of :

..

1~727ZS

BOD removed. Recalling that BOD equates one to one with oxygen demand by definition, the implication is that oxygena-tion by aeration using conventional techniques is not remarka-ble for efficiency. This reference remains valid even allowing S for available internal sources of oxygen as from the biological reduction of nitrates. This finding is to be expected since aeration efficiencies are often quoted in the range of 2% to 10%. It should be understood that the quoted values pertain ` to aeration of liquid having an initial DO of zero. This yields the highest possible efficiency. A more realistic efficiency is that for a DO in the range of 2 ppm.
The practical solution to the aeration question in activated sludge operations is set forth in my U. S.
Patent 3,853,764. The te~hn;que and equipment derives oxygen mixing efficiencies in excess of 50%. Use of such aeration ~ means in the present activated sludge operation is visualized.
- This will reduce air compressor capacity required by as much as an order of magnitude and will cut drive power require-ments of less than 1/2 usual values. This treatment method may be of any of the seven basic methods utilized in activated sludge operations. What is important is the integration of efficient gas-liquid mixing techniques with this stage of bioprocessing.
~; From the activated sludge operation, treated waste discharges to secondary sedimentation. Where the activated sludge operation is not preceded by sedimentation, the following se~;mentation operation might properly be termed final sedimentation.

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~07Z7'~5 SECONDARY SEDIMENTATION

In the case illustrated in Fig. 1, the processed waste from the activated sludge operation is discharged in a central influent as well as for primary sedimentation.
Here, however, excess aeration to achieve degassing and en-hanced flotation of grease and/or sludge is unnecessary.
With this exception, the equipment and process operation may be described for primary sedimentation previously. As might be expected, exceptions occur in the preferred disposi-tion of effluent from secondary sedimentation.
- For example, sedimented secondary sludge is removed ' conventionally and returned to the influent of the activated -~ sludge operation. Some of this flow is diverted so that excess sludge is fed to the primary digester. Clarified ` 15 effluent is discharged to disinfection with diversion of necessary quantities to secondary recirculation. To achieve desired balance between the hydraulic and organic loading imposed by secondary recirculation, intercepted partially se~;-ented flow may be incorporated in the secondary recircu-lation. This is shown in Fig. 1.
In the effluent from secondary sedimentation destined for disinfection, disinfection is initiated at the line exiting the secondaries. This technique exploits highly efficient gas-liquid mixing techniques described in the above-identified issued patent, 3l853,764. The disinfectant proposed in ozone-oxygen enriched air for several reasons.
First, this disinfectant is effective wikh the organic loads present in brief contact times. Second, this disinEectant is -36a-q c~

1C~7Z72S

potentiated, i. e., it acts synergistically in the presence of a secondary oxidizing system The secondary oxidizing system may be ferric chlor-ide added in secondary sedimentation eo promote charification, or it may be the standard chlorination additions. In either case, ozone-oxygen 5 en~iched air reduces the ultimate chlorine demand and~ensures an effluent exhibiting relatively lower chlorine residues -with high dissolved oxygen. The disinfection characeeristics of ozone-oxygen and potentiating effects of ferric chloride are noted. The standard technique adds ferric chloride to secondary sedimentation system so it cooperates with 2-3 10 added in disinfection.
DISINFECTION TREATMENT ;
According to the concepts of the present invention, a highly effective systemfor the disinfection of material ls provided according to a two stage oxidative system containing a distribution of compound of lS ammonia and ammonium and is particularly suitable for the treatment of waste or sewage effluent. A primary oxidizing agent it utilized to dis-infect the material as well as preferably to lower the pH level and a second oxidizing agent is also utilizèd. Although the oxidlzing agents ~; may be any conventional compounds which are conventional disinfectants, - 20 preferred compounds for the treatment of waste or sewage effluent comprise alurninum chloride, or ferric chloride as the primary oxidizing agent and chlorine, chlorine dioxide, ozone either by itself or preferably in oxygen or air, and sodium hypochlorite as the secondary oxidizing agents. It ha~ been found that synergistic results of oxidative disinfection ' .

.: . . . ,.. , ,,, I ....... . . 1 .. . .

: :` 107Z725 ., .
are achieved by the two 6tage treating system of the present invention wherein the primary oxidizing agent is utllized in the first stage and the secondary oxidizing agent i~ utilized in the ~econd stage. Preferably, a fair amount of oxidizing agent is added to the first stage and a ~mall S amount of secondary oxidizing agent need be added to produce an extremely low bacteria count.

i:
Preferably, the two stage oxidative disinfection system is suitable for the treatment of waste or sewage effluent. The primary ; oxidizing agent may be added to the final clarifier influent or effluent and 10 the secondary oxidizing agent may be added to the disinfecting contact tank influent of a conventional waste treatment plant or facility or the waste treatment facility as set forth hereinabove. In the treatment of ~^
waste and sewage effluent, a fecal coliform bacteria count of less than 10 parts per 100 milliliters of treated effluent may be readily and 15 easily obtained.
The use of a preferred primary oxidizing agent as set forth above has been found to reduce the pH level. Preferably, an amount of primary oxidizing agent is utilized so that the pH of the effluent coming from the final clarifier is at a level of 7 or less with approximately 6.7 ., ~ ~ ..
20 to about 6. 8 being desirable. As apparent from Fig. 18, such a pH
level at ambient temperatures will shift the ammonia-ammonium equili-brium to ammonium. In fact, subst~nti~lly or nearly all of the equilibrium will be shifted to the ammonium compound, that is in excess of approxi-~^ mately 97% and at times even 100%. Of course, if a high pH is utilized, `` 25 smaller amounts of ammonium will be present~ Generally any reduction ~ . .

. ~ .

~ ' . . .:

in Ph is desirable in that it reduces the amount of ammonia. Thus pH of8 and less at ambient temperature may be suitable. The slgnificance of the reduction of ammonia is that ammonium chloride or other ammonium compounds or complexes often exert virtually no oxldative demands when S exposed to bacterial metabolism in the presence of oxygen below a pH of 7. O. Hence, in the treatment of waste and sewage effluent, the nitrogen `~
oxidative demand will be virtually reduced to 0. In contrast, ammonia -` exhibits a substantial c>xidative ~em~nd amounting to approximately 4 1/2 times the ammonia nitrogen concentration. Thus, in conventional waste 10 treatment systems wherein concentration of the ammonia in the effluent discharged from the secondary clarifier which is in the range of 30 parts per million will require approximately 135 or l45 parts per million of :
of oxygen dem~nd. Not only does such a demar.d exert toxic effects upon a stream or body of water, it also directly effects the dissolved oxygen l5 ` concentration of the stream.
- Concerning the toxicity effects upon a stream, it is well known that ammonia in water can be toxic to fish at 4 to 5 parts per million concentration. On the other hand, ammonium compounds are not toxic and as previously noted, frequently exert no oxidative demand.
20 Additionally, ammonium compounds act as inhibitors of the exertion of nitrogenous metabolism by bacterial forms present. Thus, in addition to the synergistic reduction of bacteria in disinfection, the shift in equilibrium in the distribution of ammonia-ammonium to ammonium compounds produces`highly practical results, especially in view of the 25 regulatory agencies requiring reduction of nitrogenous biochemical .. . ..

: ~ \
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~07Z725 .

oxygen demand, and minimum practical chlorene concentrations consistent with disinfection and recent awareness of the roll of chlorene in carcinogen formation.
In a conventional or typical municipal sewage treatment plant 5 h:lnrll;ng primarily residential waste, an amount of primary oxidizing agent of approximately 85 parts per million has been found adequate to produce a pH range of about 6. 6 to 6. 7 and to effectively promote sedi- -mentation in the final clarifier. A minimum amount of at least 50 parts per million has been found to be desirable. Additionally, the amount 10 of suspended solids in such stage is generally very low. Such suspended : :
solids are precipitated in the secondary clarifier and thereby removed from the treated effluent stream.
It has been established that in the above described two-stage oxidative disinfection system wherein relatively high amounts of primary 15 oxidizing agents have been utilized, that very low amounts of secondary oxidizing agents are required. For example, where ozone is utilized, the concentration may be as low as 0. 7 parts per million whereas for chlorine, the concentration may be as low as 4 to 5 parts per million to accomplish the aforementioned disinfecting objectives, that is fecal 2~ coliform count of two or less per lOO ml. As a practical matter, the ozone feed concentration will generally be higher than the minimum amount due to the fact of inefficient mixing in t4e secondary clarifier of the oxidizing salt such as aluminum chloride or ferric chloride. Generally a maximum of`10 parts per million will be sufficient to disinfect.
25 Maximum efficiency mixing can be derived from the use of high turbulence causing devices in a flow channel such as the utilization of flat plate ".~

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orifices as above described and utilizing specific arrangements as set forth in Figs. 6, 13 and 15, of the present application as well as those taught in United State9 Patent Nos. 3, 730, 881 and 3, 805, 481.
Con.idering now an actual operating system according to the 5 present application, a first stage of an oxidative disinfection or treatment -:; with ferric chloride or aluminum chloride was accomplished by the addition of adding 85 parts per million feed. The fecal coliform count leaving the first stage ~pas quantitatively established at 109/100 milli-.
liters. The fecal coloform coùnt leaving the second stage of the oxidative 10 disinfection system with a chlorine feed ratè of 4 parts per million was established to be 0. Moreover, the degree of terminal sterilization effected is confirmed by Agar Cultures at 37C which indicate no growth. ~:
Further, in the utilization of a two-stage disinfection system as described above, it was found that a fair size chloride dose added to 15 the first stage to promote sedimentation followed by a dose of 6. 6 parts per million of ozone in oxygen in a second stage can, in as little as 8 seconds, raise the dissolved oxygen concentration to 37 parts per million.
`; Such a sample was immediately sealed after oxidative disinfection and ~ . ~
remeasured five days later. A dissolved oxygen concentration of 31 . .
20 parts per million was found. The difference of 6 relates to the fact that the metabolic activity of the surrounding forms of bacteria present had been virtually completely inhibited. This was accomplished by direct disinfection and by oxidative near kill which effected the viability of the organisms and their abilityto propagate~. Thus, the maintenance of the 25 dissolved oxygen concentration of from 37 to 31 after five days tends to approach te rminal dis infe ction .

~:. . . : . - .

107'~7'~5 System optimization in waste treatment is usually dis-cussed in terms of a fictitious constant load. Optimization may not refer to meeting ef~luent quality standards at a mini-mum combined capital and operating cost.
CHA~ KlS1s1C LOAD
The characteristic waste load on a plant is a com-bined hydraulic and organic load. It is not constant during the day. It is likely to be repetitive day to day, excepting holidays and weekends. Rain and seasonal effects impose long period changes in load.
Weekday loads may be approximated reasonably well with a geometric series of few terms. It is not unusual to find that the range in load may be as great as + 75~ of the average load. Somewhat in contrast with this fluctuating load, effluent criteria on quality typically requires that a prescribed maxi-mum never be exceeded. Practically, this means that plant regulation is aimed at achieving better quality with .95 or .99 probability. How much better the quality goal should be is a critical economic consideration.
Obviously, with a fixed output specification and a highly variable input, no fixed settings in process regulation will approach compliance and economy. An obvious approach is to accumulate mixed waste for extended times and then to treat a continuous sample at the average daily rate. This would require large holding tanks and problems of settling, septicity and cost arise.
Despite these problems, a great advantage aCcrues from the constant hydraulic and organic loading obtainable by ~'', .. . . . . .
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10'7Z7ZS

optimum system utilization. The basic advantage is simplicity of controlled regulation of the plant process. The plant is essentially a servo system. To get a fixed output at a pre-scribed level, it would obviously be easier to find the fixed process settings to meet this level where the input is also fixed. With the actual input, the best process design and control is a then sophisticated problem. Although this problem is a basic one, economically, it has not yet received the attention it deserves.
In the equipment and process implementation of this concept, a dual attack on the design and control problem is proposed. Basic to the attack is provision of adequate flexi-bility in process control to enable a close approach to uni-form hourly hydraulic and organic loading over a typical oper-ating day. This m;n;r;zes the magnitude and effect of imposed fluctuations in hydraulic and organic load. The second basic element of approach is to provide process control to operate on the suppressed load variations to achieve the desired level of effluent quality continuously. This yieIds the optimum system in terms of ;n;m;zed total cost to derive continuously the acceptable quality of effluent. Calculated performance, process conditions and basic factors in total cost have been determined and are set forth in more detail hèreinafter.
With respect to the system optimization, the ideal ~5 solution requires excessive se~;m~ntation tank capacities, ~`
botl~ in the primary and the secondary tanks. The practical answer is to compromise the flow.
`~ The Example A shows that for an arbitrarily varient : inflow rate and organic load concentration, it is possible A
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~07Z725 to achieve a process influent having a constant inflow rate and a constant organic load concentration. The demonstrated condi-tion pertains to the sedimentation tank influent in each example. Thereafter, in the process, the hydraulic load varies with time, but the organic load concentration is held constant.
The compromise condition allows a variation in hydraulic and in organic load to the sedimentation tank. Lower total influent rates to primary sedimentation result. The design condition is imposed next in the process. This means that the interval a-b overwhich integrals are considered is short or that point values are used. In addition, a simplified on-off control to approxi-mate the exact solution is shown. This substitutes a rectangu-lar region for integration in place of the region beneath a trigonometric curve, or an actual plot of station load, hydraulic and organic. Case D shows that where Ql=3.0 for the 24-hour day rate, a total flow of 3.8 provides an optimum system flow. The flow condition yields a close approximation to constant organic load concentration to the trickling filter, as shown in the graph of Fig. 11. In an activated sludge process, the concentra-tion could be held constant by return sludge rate controls.
Hydraulic loads would vary in either illustration of ~he solid graph Dl, or the dotted graph D2 of Case D.
Case A--Schematic flow sheet shown in Fig. 10 illustrates t conditions for uniform hydraulic and organic load with an arbi- ~
trary variable incident load. The figures shown between sections in Fig. 8 are the BOD of the treated waste in ppm. Case A, also shown by the graphs of Figs. 8 and 9, uses process control w in Ql' Q3, Q~ and Q5 Q2 may be held at zero.

.~

, .. ~.. . -\i . . i , Maximum Load -- Q = 1. 4 MGD B = 350 ppm.
Secondary recirculation for 10:00 AM/PM load.
1. (BOD) 83. ~Q + Q3 1 = 1. 4 x 350 + Q3 20 1.4 35; 83 1.4 Z67 Q3 = . . = = 5. 93 5. 93 - 1.4 Recirculation ratio; R = 1. 4 = 3. 24 Flow to primary: 5. 93 MGD rate , ; "

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.~ 107Z7ZS

: Secondary recirculation for 8:00 and 12:00 AM/PM load, 83x 5.93=l.lx 275+20 Q3 =58~483- Q3]
Q3 =107.5/38=Z.83' Ql=4-83- Q3-2,0 Secondary re¢irculatlon, other flows, 7:00 and 1:00 AM/PM, This i8 the average load condition.
83~ 5.93=.8x 200 +20 Q3 + 58~5.13- Q3]
and, if Q3 iæ zero:
5.93x83=. 8 x 200 + 20 Q3 +58[5.13- Q3]
492 +34=20 Q3-58 Q3 Q3 = -34/38= appr~ximately -1. 0 ;~ ~ LI. Casc for 8:00 and l2:00 AM/PM
83 x 7.33 = 1.1 x 275 +20 Q3=58[6.23- Q3]
610 =20 Q3- 58 Q3= -38 Q3 ~` 15~ - Q3 =54/38= 1. 42 ; ' Ql=6.23-1.42=4.81 III. Case for 7:00 and 1:00 AM/PM Average load, ~ 83x7.33=.8x 200 +20 Q3 ~58[6.53- Q3]
`~ 610- 160-379=71= -38 Q3, but for Q3=0 0 71=58 Ql- Ql-71/58=1.23 flow check 6.53 B +.8x 200=83x7.33 ~ 6.53 B =450 `~ B =450/6.53=69 flow must shift to Ql+Q4 continued percent solids primary 3% and percent solids secondary 6%
. Primary sludge 3% at 7. 33 MGD = ,22 MGD
BOD =83- 58 approximately Average supplied = approximately 2500.

,- 107Z7Z5 IV. 83 ~ 7. 33 = . 8 x 200 + 600 Qa~ + 58 ~6.53 - Q
+ 71 = 600 Q4 0 58 Q4 Q4 = 71/542 - .131 MGD
then Ql = 6.40 MGD
S V. Conditions at 6:00 and.2:00 AM/PM
83~7.33-.5+125+600Q4+58'r6.83-Q4~
151 = 600 Q4 - 58Q4 Q4 = .279 MGD
Ql = 6. 55 MGD
VI. Conditions at 5:00 and 3:00 AM/PM.
83 ~ 7, 33 =,28 ~ 70 + 600 Q4 + 58 1 7. 05 ~ Q4]
181 = 600 Q4 - S8 Q4 Q4 = 33 MGD
Ql = 6.72 MGD
VII. Conditions àt 4:30 and 3:30 AM/PM
83 ~ 7.33 = .22 x 55+ 2500 ~ Q5 + 58 [7.11 - Q5]

Qs = .0&9 MGD, or showing alternative for secondary ~ludge method o digestes supernatant 83 ~ 7,33 - .22 x 55 + 600 Q4 + 58 ~7. 11 - Q4~
~ 186- Q4 ~600 - 58~ ' Q4 - . 343 MGD
Q 1 ~ .6. 77 MGD
Conditions at 9:00 and 11:00 AM/PM
83~ 7.33 = 1.32 x 327 + 20 Q3 + 58 r6.0 -VIII. Conditions at 8:30 and 11:30 AM/PM
83- 7.33 - 1.22 x 305 + 20 Q3 + 58 r6. 11 - Q3]
Q1 = 3..11; Q3 = 3.0 .. _ ~ .... .

IX . Condition at 9: 0 0 and 11: 0 0 AM / PM
83~7.33=1.32x330~20Q3+58~6.0-Q
-174. = -38 Q3;
Q3 - 4.58;Ql= 1.42 X. Condition at 9:30 and 10:30 AM/PM
83 7. 33 ~ 1. 38 x 345 + 20 Q3 + 58 ~,5. 95 - Q~
-211. = -38 Q3; ~3 - 5. 55 Q1 = 4 ;` ^ Case A Pump Capacities -- Flow around primary sedimenta-10 tion equals gravity. Flow around trickling filter equals zero. Flow :
around secondary sedimentation equals Ql ~ Q4 = 6. 4. Flow from sec-ondary sludge equals 0. 4. Then, 0. 400, 000. /24 60 - 278 GPM. Use 300. GPM 2:150 GPM Secondary 6.4/1440 - 4,450. ;-Use 4:1200 GPM.
Equipment sizing Case A
Prirnaries: 4 60' Diameter Secondaries 4 60' Diameter Trickling Filter 2 75' Diameter System Characteristics -- Large sedimentation requirements.
Moderate Pumping requirements. Conservative bioprocessing re-20 quirements. Fixed effluent BOD to chlorniation of 20 ppm, with influent BOD's from 50 to 350. BOD reduction is from 94. 3% to 43%.
A second case may be examined. It reduces primary and secondary sedimentation requirements, as it appears that a practical variation from the illustrative Case A which has been described above, 25 is based on a compromise at the peak flow condition occurring at 10:00 AM/PM.

: . :., ' '! `
`` ` 107Z7ZS
The compromise is to accept a system condition as at 9:00 or 11:00 AM~PM for the hydraulic load. An organic load in ppm can be held constant. Instead of the ideal situation, holding the hydraulic load constant, 24 hours per day, we hold the system hydraulic load at the 9-11 level. Then, in the interval 9-11 AM/PM, i.e., twice a day, for 2 hours, a hydraulic over-load is allowed. This only affects the primary and secondary sedimentation tanks, and not seriously, in comparison with the cost reduction enabled. Except in the interval 9-11, the sys-tem hydraulic and organic load may be held constant.
; ~ Of course, other compromise ç~pe~ients may be selec-ted. For example, the interval might be 8-12. For the three cases, A, 9-10, 8-12, the relative flows are 1.4, 1.32 and 1.1.
Most state laws require that se~ tation tanks be proportioned to accommodate specified overflow rates expressed as MGD per unit of surface area. Thus, reducing from 1.4 to 1.1 means that the required area reduction is 3/1.4 which is roughly proportional to the cost reduction.
e all or none flows are typical of praotical manual control. Valve settings may be made and left for an appreci-; able time. This type of control is also amenable to automatic ,.. .
~ - regulation of the plant. Simple time controls can accomplish ~ .
this type of regulation.

:

_49_ :' ~.

, ~ - : : .~. .

` ' lC~7Z7ZS
.
The previous discussion involved more sophisticated control~
typical of usual servo control system. The foregoing conditions are a convenience in calculation. The calculations set forth above and the graphs of Figs. 8 through 11 are based on controls of deiinite integrals:
5 The integrals concerned are of the form:
Q = b q c dt ~ where:
Q is an organic load a, b are time limits for the load increment considered ~-q is a flow rate dt is differential time.
.~ .
In effect, control is based on manipulation of definite integrals to approximate organic load concentrations at indicated points in the - overall process. A particular case is shown at the influent to the ~ .
sedimentation tank where the organic load and the hydraulic load are 15 held at constant values. The effect on increased overflow rates at the sedimentaticn tank has been noted above.
` ~ ~ To relax the overflow rates at primary æedimentation, it is feasible to impose the condition for constant hydraulic and organic load i .
; ~ at bioprocessing. For a tricking filter or an activated sludge unit 20 operation, it is desirable to hold the hydraulic and also the organic load constant. This is particularly so of activated sludge unit opera-tions. To illustrate this condition, a limited number of calculations as set f orth above are indicated to show a typical solution.

~ .

~ -50-DISINFECTION SYSTEM
The disinfection system indicated in Fig. 5 of the drawings is a gas-liquid mixing system operating under a hydraulic pressure gradient. It is comprised of a liquid oxygen supply 200, an ozone source S or generator 202, an oscillator power supply 204, and a process flow line indicated generally .

;' -50a--, .

by numeral 206. The line 206 operates in the regime of tur-bulent flow, at or above a Reynolds number of 3,000. High momentum exchange mixing elements are carried in at least cer-tain of the T-shaped flanges 208. These mixing elements are normally flat plate orifices 208a which induce intense ix~ng sufficient to ; n; ; ze radial concentration gradients in the processed liquid effluent entering the flow line 206 at 209.
The mixing elements 208a may be followed by sting-type canti-levers 210 driven by a tunable source 211 excited at or near their natural frequency. These may be positioned in relation to the gas injecting means to further enhAnce the momentum ex-change in primary regard to minimizing concentration gradients occurring in the angular direction in addition to the radial gradient suppression induced by the basic mixing element, the flat plate orifice. In addition, the primary objective is to have the stings 210 provide ?ch~n;c~l disruptive forces on flocs, plaques, or agglomerates which may be present in the processe~ liquid effluent. The objective of imposing disruptive ~; forces is to reduce the size and to extend the available surface for disinfection on such flocs, plaques or agglomerates.
The orifices 208a in the T's 208 are provided at the flange joints as a matter of conven;ence~ The orifice diameter ratio to the pipe diameter is typically equal to or greater than 0.7. In the T's 208 securing the orifices 208a, two other ele-ments are mounted. One is an 3-2 injector 212. The injector 212 is introduced in a fitting ideally centrally allowing axial positioning which extends through the orifice perferably to or slightly past the vena contracta formed by the flow through the orifice. Optimal injection is found to be with minimum conc~n tration gradient in the flow direction. This is most conveni-ently obtained by making the fluid flow rate steady over short or longer intervals of time and by similar proportional control of gas flow. The sting 210 is the ............................

:. . : , . . . .. . . .

second element introduced wlth similar provision for axial po~itionand sealing as the injector 212~
The O3 - Oz injection occurs at approximately 5% or less con-ce,ntration by weight of ozone in oxygen. For general~zed disinfection, it 5 is introduced in amounts greater than 0. 5 milligrams of ozone per liter of fluid. The injected concentration will attenuate in the flow line. Two factors cause the attenuation. One is the decomposition rate for O3 in water leading to 2~ The second attenuating factor i8 the oxidation .
` ~ load of the material contained in the processed liquid. ln the typical 10 waste, this is comprised of organic materials incompletely oxidized ` to stable forms. These materials in conjunction with oxidizable inorganic constituents comprise the BOD load of waste.
~9 ~ Recognizing that O3 attenuation which will occur, `it may be necessary to utilize sequential injection. This aspect is shown in Fig. 5.
15 Fig. 5 also indicates a series of test points in the flow line between injection points for the O3 which include sensors 214 that act to control ~ .
a power supply Z04 to the generator 202~ These sensors 214 are useful to access quantitatively the O3 concentration and the BOD reduction. For a given Reynolds number, these data provide information on time and 20 position. This information is essential for design of the flow system and for determing the optimum O3 injection flow rate. For generalized disinfection, it is important to the invention that the injection rate and interval be such that the attenuated O3 concentration exceeds 0. 5 milli-grams of ozone per liter of effluent at all points in the system in which 25 generalized disinfection is to occur. In contrast, specialized disinfection .`~ . , . ' . .. , . ` '.. . " '.`.~ ' ' '. ... .

~~

as of obligate anaerobic forms of bacteria may be sustained with air or oxygen containing only trace quantities of ozone as usually found in concentrations of 0. 01 ppm or less. This process and implementa-tion is detailed in my above identified copending application.
From the above, the purpose for sequential injection is clear.
The number of points, or the distance or time in the flow line will depend upon the impressed oxidation load and particulate size of this load. It is anticipated that in normally operating systems, the time for processing will not exceed 8 minutes. It should be understood that the piping system indicated in Fig. 5 will normally extend in a vertical direction wherein the entrance at 209 and discharge at 216 are at com-parable horizontal locations so that in essence a hydraulic gradient is present when considering the system as a whole. The relative vertical :-location of these points is immaterial to the effectiveness of the dis-infection system.
The actual construction of a T 208 showing the flat plate orifice 208a, the centrally positioned 2 ~ O3 injector 212, and the o~cillating ; ~ sting 210 in greater detail is shown in Fig. 6 of the drawings.
The invention also contemplates that excess oxygen can be picked off the piping system at point 218 by a suital~le pump 220 and sent into a drier 222 for transfer therefrom through a control valve 224 into the supply line from the liquid oxygen source 200 to the ozone generator 202.
A suitable power supply 226 activates the drier 222.
Ab absorber indicated by block 230 might be included to receive the output from generator 202 before passing the ozone concen-trated fluid into a supply line 232 so as to remove all excess oxygen ,, , ~. , . : ., ~
." . ~" ,. ,. . , ` ' ', ~ `' '.............. ` ' . .. . ..

with the excess oxygen fed back over line 234 and through valve 236 to the supply to generator 202. The absorber 230 is optional as the 3 ~ 2 concentration can pass directly through line 238.
In some instances, it might also be desirable to have processed liquid effluent entering at point 209 into the piping system Z06 pass through some type of deaerator or absorber to degas or desorb 2 out of the effluent since you can't get new O3 into the fluid in an 2 carrier gas if the fluid is saturated with 2 A dotted line 240 illustrates this optical arrangement.
It should be understood that the system described hereinabove calls for the preferred implementation utilizing a liquid oxygen feed. An oxygen enriched air feed to ozonation may be used with or without re-cycling and oxygen make up to be described hereinafter. Either of these may be refined incorporating recycled, dried, and recovered oxygen.
However, continuous recirculation may not be feasible, and in this case it is apparent that there exists a deslrable bleed-feed rate for the oxygen supply. The rate should satisfy the DO requirements on effluent and the argon dilution problem whereby ozonation efficiency may degrade with increasing concentrations of cont~min~nt gases. Also, the installed capacity of the bleedfeed 2 supply should be at the average anticipated 3 ~ 2 (1em~n~. This will minimize the capital investment required.
With reference to the passage of the effluent through deaerator or absorber 230, it has been found that 7 to 40 ppm may be recovered from the effluent before discharge for use in the oxygen enriched process in the waste treatment system. Other techniques other than deaeration "" ,: ; '. : :

1~)7Z7Z5 or desorbing that might be utilized ~uld either be heating or cavita-tion, where the cavitation might involve ultrasonic excitatlon a~ set forth in my above identified co-pending application.
It should also be noted that the entire disinfection process set forth preferably uses oxygen enriched air, not air, thus minimizing the impact of high nitrogen concentration or ozonator efficiency. In using oxygen enriched air or oxygen as described, a number of signi-ficant improvements naturally follow. For straight oxygen it is a known physical fact that the potential solubility of oxygen in water if five or six times as great if introduced in equilibrium for oxygen enabling a higher concentration of o~one to be injected while less oxygen is required. The elimination of oxides of nitrogen contributes to safety and air pollution control. Further, the availability of oxygen for recycling and for process enhancement reduces the oxygen expense by an order of magnitude or more while the process enhancement is increased as pointed out above.
Also, recoverèd oxygen may be utilized in the trickling filter or activated sludge operation by oxygen-effluent injection, or by enrich-ment with this oxygen of a basic air-effluent injection means. In this way a trickling filter bed should maintain aerobic metabolic rates at '`
maximum quantitative levels throughout its entire depth. A similar effect on the activated sludge operation is possible. The effect on increased BOD reduction is apparent.
FORCE MAIN INJECTION
The aeration for force main injection has been practiced in the range of 4 parts of air in from 10, 000 to 100, 000 parts of fluid by .. . . . .

, ~

weight. The volume concentrations need not exceed 50% of air in liquid. For force main injection, useful results may be realized to much lower levels, perhaps aæ low as 1-5~o by volu~ne. Wet well aeration may be effective at appreciably lower feed rates. The limi-tation for this case depends on degassing at the impeller eye, leading to eventual loss of pump prime. This problem is more fully covered in my above-identified co-pending application.
The satu~ation levels for aeration of water are near 20-30 parts per million by weight. For waste, somewhat lower saturation limits may be expected in view of the pr esence of additional contaminating gases and dissolved materials, i.e. for aeration. In the oxygenation case, water saturation levels are in the range 40 to 5 ppm, by weight. For ozonation, with oxygen as the carrier, at 6% ozone in oxygen by weight, the saturation range corresponds to ozone in liquid concentrations of lS about 2. 5 ppm, by weight. The foregoing ranges may be useful as depicting preferred ranges of gas concentration.
As is shown, force main operate intermittently according to the influent rate to the wet well and the level settings used to control the pumps. When the pumps shut down, a pressure wave travels through the system, is reflected, returns, and oscillates periodically ulti-mately damping out. The pressure 1uctuations occur below and above the static pressure level in the line. The pressure differences may compare with the dynamicstatic pressure difference or they may exceed this difference. Such pressure waves are reerred to as water hammer. Air present in orce main incident to aeration to control :

,., ::

~07Z7Z5 septicity affects these pres~ure waves. The presence of air reduces the pressure differences, it reduces the velocity of the pressure wave~
in the force main, from one end to the other and the air damps out the pressure oscillation rapidly in a reduced number o cycles, all in comparison to the force main response to pump shut down without air inJection to the force main. All these results are beneficial and are a -bonus accruing from the practice of air in~ection to orce mains. Thus, - it is apparent that force main used for waste, water, or liquid generally, such as oil, may benefit from aeration, or inert gas injection as with engine or boiler exhaust gas, nitrogen or carbon dioxide. Preferred- gases are those which are not unduly reactive and which exhibit low saturation ~ ~., j .
levels in the liquid transported. This reduces the gas compressor capacity required to inject an excess of gas beyond the saturation con-centration. The beneficial results on pressure reduction occur pre-domin~ntly from undissolved gas.
SURGE SUPPRESSION
Pipe hammer or surge suppression can be abated or greatly reduced by injecting an amount of gas in excess of the saturation level of a gas in a liquid. Desirably, a large excess is preferred such as 2 0 from 5 to 10 times the saturation level. Generally, an excess of -. . ~
twice the satùrated level is necessary to produce suitable results.
~. ~
.. ~ .
~ ~ Preferably, to ensure that the saturation level is reached, the gas is . .
injected at a highly turbulent region of flow in a liquld piping system such ~; as a main or transmission line as exemplified by a pipe. Generally, any type of device for causing high turbulence may be utilized. A
, . ' ,: , ~

` -'' :
.

., , . , ., , :

specific example of such a device is illustrated by Fig. 6, previou~ly described. Although Fig. 6 shows a Tee with one portion blocked off, the same apparatus may exist in an elbow or the like or desirably in a straight flow pipe. According to the present invention, gas injector means 212 injects a gas into the central portion of the flow pipe of a force main or transmission line within or slightly past the high turbu-- lence regime of a high turbulence causing device such as a check valve or in the vena contracta formed by flow through orifice 208a. In such an area, any longitudinal and axial concentration gradients are minim;7ed. A second mixing orifice downstream at a transition length or more tends to suppress radial concentration gradients.
Yet another type of a high turbulence causing device or member cont~ining a gas injecting member i9 shown in Fig. 13 which i9 deg-cribed below in detail with respect to the injection of a polyelectrolyte resin solution. Short tube 145 within a flow pipe or tube 147 causes a region of high tulrbulence mixing. Thè entry into the short tube sectian :
145 is a 1at Qr blunt 90 annular flange 151. The location of the in-ection member or tube 153 is preferably at the vena contracta of the flow. Preferably, the tip of injection tube 153 is located in the center of short tube 145.
Another example of a high turbulence causing device in this case containing a gas injector member i9 shown in Fig. 15. In Fig. 15a, an injection mixing elbow generally indicated by the numeral 222 having an orifice 224 i9 located with the elbow at the commencement of the radius. A pipe 225 is attached to the elbow in any conventional manner.

I . .- ~ i. ., - ,, . . :. .
',.. ~ ' A small diameter pipe or rube 226 i8 inserted through the elbow and through the orifice 224 ~o that the tip 232 i8 located within the high turbulence and desirably at or near the vena contracta portion down-stream of which full mixing occurs within the flow line or pipe generally indicated by the numeral 2ZS, The location of the tip 232 of small injection pipe 226 is important with respect to thorough mixing and suppression of concen-tration gradients . Generally, tip 232 may be located from about 0. 25 to about 0. 5 pipe diameters downstream or at a highly preier,red distance of from about 0. 36 to about 0. 39 diameters with about 0. 375 diameters being the optimum location. ,,~
A flat plate orifice which may be utilized in the elbow is shown in Fig. 15c. Generally the orifice diameter is from about 0. 7 to about 0~ 9 of the conduit diameter and may have a taper (at about 60) leading .
from the -orifice opening. In Fig. 15B, orifice 224 is located within a ;; coupling or union, generally indicated by the numeral 310, and connects -` the pipes or conduits 301.

, ~ .
'5 . .
-59~

;
:~
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.

Fig. 15b shows the flat plate orifice in a coupling.
Of course, the orifice can be utilized at numerous locations such a~ tees, elbows and the like or simply in a straight por-tion of a conduit.
As should be apparent to one skilled in the art, numerous types of turbulence causing devices containing gas injectors such as small pipes may be utilized. However, in situations wherein the monetary expense of gas injection into a pipe or the like is low, high mixing efficiency as exempli-fied by optimal, i.e. flat plate orifices with coaxial injectionmay not be required. Rather, it is sufficient to inject an amount of gas into a liquid such that the total amount of gas :::
is in excess of that required to reach saturation within the flow pipe. Thus, the gas may be injected as through a normal straight portion of a pipe line or in many other locations such as at a check valve following a pump, in tees, elbows, valves or wherever turns or fittings cause turbulence.
Preferably, turbulence causing devices such as ori-fices or turbulence causing fittings or turns are located down-stream throughout the liquid flow system preferably separated by at least one transition length e.g. from 25 to 40 pipe dia-meters for turbulent flow and preferably more than 40 diameters ,.to maintain the saturation level of the liquid or to cause the saturation level to be reached where it i6 not reached through the addition of the gas through a non-high turbulent area as ' .

:

through an elbow. The amount and number of such devices will depend largely upon the system utilized as should be apparent to one skilled in the art.
The net effect of the addition of an excess amount o~ gas above the saturation level of the liquid is to provide a distributed air chamber along the entire length of the flow pipe and system which acts as a distributed surge suppression air Ch~ ~ cr rather than a discrete air ch~her. As above noted, preferred gases are those which are not unduly reactive and which exhibit low saturatio~ levels in the particular li-quid transported. Of course, numerous gases may be utilized.
Specific preferred gases generally include: oxygen; ozone preferably in a carrier gas, e.g. air, nitrogen, etc; nitrogen;
carbon dioxide; air, natural gas, exhaust gas, e.g. from a diesel engine driven pump, distillate gases such as propane, ~.
butane, pentane, etc. and the like.
Although the above described surge suppression system ~; may be utilized in generally any liquid flow system, it has :
` been found to be particularly suitable in suppressing surge pressures in any liquid transmission system such as the flow system of a waste treatment facility such as set forth above ; ~ and may be added in the force mains.

AERATION OF MUNICIPAL COLLECTION SYSTEM

A dispersed municipal collection sys æm was equipped :

.

. ~
~, `' ~07Z7ZS

with aeration equipment according to the principles set forth. Before aeration, waste received at the processing plant was septic, exhibited zero or trace dissolved oxygen and exerted no demand on oxygen satur- -ated in the waste after it entered the plant.
S In contrast, after all force mains and wet walls were aerated, the dissolved oxygen of received raw waste reached 3 to 4 ppm. The waste was treatable as indicated by its oxygen demand of more than 10. 0 ~- ppm per hour. The dissolved oxygen content sufficed to sustain aerobic :
. ~
conditions throughout primary sedimentation. The effluent from this irst stage of processing still exhibited a dissolved oxygen concentration exceeding l. 0 ppm. These results dramatically attest to the efficacy of these teachings of aeration. The desired suppression of odor from septic decomposition was a noticeable further result. - ;~
CHLORINATlON
, ~ , ..
;15 ~ It should be understood that the invention further contemplates ~
..~ .
that chlorine mixing utilizing the flat plate orifices and injection at numerous points under high momenturn exchange mixing conditions is clearly possible. The use o chlorine in a gaseous state for gaseous mixing injection or as a liquid solution is contemplated by this inven-tion. Fig. 1 illustrates more typical points of injection for a chlorine and water solution through line 40 into line 36 to the effluent from the secondary sedimentation tank 24. Further, the invention quite definitely contemplates the injection of chlorine in the disinfection portion 38 of Fig. l.
.

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1(~7Z7ZS

- . SEDIMENTATION
The invention contemplates the injection of aluminum chloride or some other suitable sedimenting agent into the effluent at some point in the process preceding the final disinfection contact element to assist in clearing the water when it is finally discharged into a receiving stream, river, or the like. With the use of aluminum chloride, the invention contemplates the injection of about 2S to 100 parts per million, with this being followed by a polymer injection after a delay of two or three minutes. The aluminum chloride injection might take place :Eor example in a somewhat rectangularly shaped trough 135 mounted in the bottom of the trickling filter tank 120 of Fig. 4. This trough 135 would collect all the water which trickled down through the filter media and then be passed through the output hne 138. In order to inject the alllminnm chloride into the effluent at this point, a plurality of transversely extending pipes 137 are mounted to extend across the trough 135, again as best seen in Fig. 14, with the alumlnum chloride injection being through a pipe 139 which individually communicates with each of the four pipes 137 illustrated in Fig. 4.
Further mixing of the aluminum chloride is then followed in its passage of pipe 138 by entry into a multiple short tube s.ection indicated by numeral 141 which is primarily designed for mixing. In addition, because of the slow flow rate through the trough 135, the injection of a polyelectrolyte resin may be made with coaxial injection into the vena contracta, into the end of the multiple short tube section 141 to achieve the affect of a flocculating agent as is well known in the art.

~ .}-~

; ,, .

` . `:.
The short tube effects a highly effective mixing arrangement. A
single short tube i9 illustrated schematically in Fig. 13, and i~ illus-trated generally by the numeral 143. The tube in effect comprises a reduced diameter short tube section 145 which is coaxially mounted within the outer normal diameter tube section 147. The entry into the short tube section 145 is with a flat blunt 90 angular flange ISl so that considerable and extreme turbulence is present within the short tube section 145. The injection of the polyelectrolyte resin, or any other suitable resin might be through a small injection tube 153 which is ``10 ~ positioned 80 as to be approximately 0. 7 5 diamete rs of the small tube 145 from the entrance with the flow being in the direction of arrow 155. `~
Thus, with the~short tube, it should be understood that the ", ,~
entrance from the tube creates a mixing, and that such short tubes can be positioned coaxially or may normally occur in existing conduits i. i ' :~ jS: ~ or extensions of exi~tiDg conduits. For example, in the seotion 141 ~ -t~i- contemplated that perhaps three hort tubes would be arranged in s~ide by side bundle relationship with fLow being in one end of one ` ~ `
down tbrough and reversing its direction a third time to pass out through a third short tube witb flow being in parallel.- This particular short 20 ~ ~ tube arrangement might actually have a total length in the three short tubès of twenty diameters of an individual one, and preferably should not have Iess than a ten diameter length.
It is, however, desirable that the mixing be accomplished under a low shear condition, particularly for the polyelectrolyte`resin .~
which should be inserted at between . 2 to . 6 ppm and between 1 1/2 to 3 1/2 minute~ following the injection of the alnm~inum chloride.
:~:
64 :.

~0727ZS

It should be fed at an actual concentràtion of .1% or les~ in water.
Again, with reference to the short tube, the transition length of the tube should be greater than . S and preferably between about . 75 to about . 9 with these figures being the ratio of the orifice diameter to the actual diameter of the large flowing pipe or pipe 147 in Fig. 15.
In other words, the length of the tube should be as close to 25 to 40 diameters, a complete transition length, as possible.
~; In actuality the stream within the short tube of Fig. 13 if flowing under high pressure is probably contracted somewhat more for a given depth of water or given pressure head. We have found that the best length for the tube 145 should probably be about 2. 5 diameters.
Under these conditions, the head loss is 0. 328H where H is hydraulic head upstream of the tube if the tube 145 is vented, it may allow full flow through the tube rather than the contracted flow defined above.
1 S However, we have found that no venting of such tubes needs to take place. Actually, for most efficient mixing, a non laminar flow through the tube 145 is highly desirable.
The use of the short tube also is achieving mixing under a hydraulic gradient, rather than a gravitional gradient, and in this manner, high efficiency as well as saturation above existing levels in ~ gravitational systems is definitely achieved.
; ~ Another important aspect of the introduction of gas into the systern by inserting more gas than that r~ uired to saturate the liquid downstream of the pump i~ that pump prime is not lost, but that in this manner pipe knock caused by pumping is signiicantly dampened.

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. ~ .

. - . ~ . . ~ ~.

~0727Z5 NITRIFICAT ION
Standard processes involve carbonaceous BOD reduction.
However, new state and federal requirements are being imposed for ; nitrogenous oxygen demand or NOD reduction, or NOD. The proces~
defined above, and particularly that as associated with Fig. 1 of the drawings as being the optimum system uses either all nitrification teaching, or all break point chlorination, or a split somewhere between these two. Preferably, the system should be based on a two stage ~ ` trickling filtration with return of stabilized digester supernatant. This - 10 makes the trickling filters convert all the nitrogen to ammonia or NH3.
NH3 is then separately oxidized to nitrate, or N03 or by break point ~; chlorination to monochloramine .
The oxidation of the NH3 to N03 requires four to five to six times the NH3-nitrogen concentration currently available in present systerns. Specifically, this amounts in the system designed above to - ~ 140 ppm of oxygen. Thus, for properly aerated waste with oxygen, a closed extend3d out fall line would allow the oxygen use to achieve the ; ~ breakdown of the NH3 to N03. This would preferably be done before disinfection, and is shown by the CL2+ H20 injection over line 40 in Fig. 1. Then, dlsinfection would occur after nitrification. It seems more practical to utilize a supplemental aerobic process such as an aerobic nitrification unit as described in this specification.
In this unit effluent may also be under a pressure in its flow path, so that it will be under several gravities load, for example~
Under this processing condition, much greater concentrations of gas or fluid can be saturated thereinto. The effluent would be maintained ~07Z7ZS ~

under pressure until processing was fully completed. Aeration is believed to be more efficient and easier under such a pressure system.
The various embodiments of the present invention can be utilized to achieve an optimum process for the conversion of ammonia to ammonium nitrates, particularly in waste or sewage treatment plants.
In general, the ~econdary treatment effluent from a waste or sewage treatment plant can be fed to a nitrification tower and treated in a manner and method as set forth in Water and Sewage Works, August, 1974, Pages 92 - 94 which is hereby fully incorporated by reference with respect to the manner, processes, equipment and techniques utilized to produce low ammonia effluent including the utilization of a plastic media trickling filter such as Surfpac supplied by the Dow Chemical Company. Utilization of applicant's various apparatus processes and technique will result in an improved process with the production of even lower ammonia effluent concentrations throughout the year.
According to the concepts of the present invention, the secondary : ~ .
treatment effluent may be fed to the nitrification tower through a dis-tributor arm hereinbelow described in detail. The primary advantages ~; of util1zation of this distributor arm is to distribute an even amount ZO of eflluent to each area or square foot of the nitrification tower, regardless of whether it is located near the center ~ the tower, at a mid portion of the tower or at a radially outward point. This results in an improved efficiency of distributlon and hence better utilization of available area for nitrification.

'; ' .. :, . :,;. '- ' . ~ ' . . .'.; '.. ;.. ~ ' .; ' . ,, The secondary treatment effiuent can be aerated for feeding to the nitrification tower. Aeration or the introduction of dissolved oxygen into the effluent can take place in a manner set forth hereinabove. A
; preferred introduction is the utilization of an injection nozzle into the conduit within the vena contracta portion of a turbulence causing device such as a flat plate orifice as taught hereinabove. A preferred amount of oxygen is from 2 to 5 parts per million parts of a secondary ~; treatment effluent. The provision of the oxygen, of course, promotes nitrification or conversion of the ammonia to nitrate. ~`
Another aspect to improve the conversion of ammonia to nitrate involves the utilization of packed media within the nitrification tower as hereinafter described such as Berl saddles, pall rings, and the like or the specialized media described above wherein the hydraulic radius of the external flow channels is substantially equal to the hydraulic radius of the internal flow channels. This provision insures thorough and efficient mixing and hence a greater conversion. Although the plastic media trickling filter (Surfpac) or rotating media ~BlOSURF) may be utiiized, the packing media having the hydraulic parameter of equal ~nternal and external hydraulic radius is preferred. ::
Generally, due to temperature dlerence, it is harder to - produce a satisfactorily low level of ammonia effluent during the ~nter period then it is in the 6ummer. Hence, another expedient includes the :~

-68_ - .

provision of insulating the nitrification tower to sustain warm effluent tëmperatures and this is facilitated by minimi7.ing the ambient air flow through the packed bed which would otherwise suppress reaction rates owing to the cooling which would be induced. This air flow is unnecessary with an aerated inflow into the nitrificatlon process.

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~07Z7;~5 SYSTEM INTEGRATION
The arrangement of the overall units of Fig. 1 can function in waste treatment. One mode of operation is to allow all elements to float on line as the influent hydraulic and organic load changes. Typical changes in these two loads are high. In terms of an average daily load, the range may be as great as + 75% of the average load. Regulatory authorities usually stipulate that at no time shall prescribed limits for effluent quality be exceeded. With a highly variable input load, this means eitherthàt the process must be controlled to over treat waste most of the time, or that relating sophisti-cated control is necessary to achieve the necessary degree of treatment at any time. Both capital and operating expenses are lower in the latter case. However, the usual engineering unit tends toward the former teahnique. It is the approach and simplified controls and regulation to achieve a degree of treatment satisfactory for a fixed design condition. For any ~; other input loading, effluent quality will vary. -Tests have shown that using the system with the sedi-mentation tank defined herein the DO level to the tank is about 2 to 3 ppm, and out of the tank about 1 to 1-1/2 ppm to defi-nitely maintain the aerobic condition. This aerobic condition L~ -; n~ between 20 to 40 minutes after the effluent leaves the -~ se~i -ntation tank.

- , . ' ,. :,: ` ' SCRUBBER
According to the concepts of the present invention, a scrubber including an air washer may be provided for puri-fication as in the deoæonation of an ozonated gas. That i8, the residual or unreacted o~one from the sewage waste treat-ment facilities as above set forth may be treated to effective-ly remove the ozone from the gas medium. Whenever a scrubber is utilized, it is to be understood that a washer may also be utilized.
A two stage scrubber, generally indicated by the numeral 250, is shown in Fig. 16. Scrubber 250 may generally be any conventional scrubber and therefore contain a packed media 252 such as Raschig rings, Pall rings, Berl saddles, single spiral media and the like. The treating medium may be inserted at the top of the first stage of the scrubber, through reagent feed line 253. The treating medium will, of course, trickle down through the first stage ànd collect in drain 254 from which it flows through drainline 255 to a make up tank 256. The treating medium may then be recycled by recirculating pump 257 or a portion may be discarded as through waste line 258. Make-up may be supplied to tank 258. A reagent supply :: ` :
tank 259 having a pump 260 may be located to discharge to an injection i~ing system on the pressure side of the recircula-tion pump 257. Reagent make-up to the metering pump sump may be controlled by float or other sensing means. Sensing may detect a reagent or treating medium parameter.
~ he fluid to be treated in the scrubber is admitted to one end of the scrubber as indicated in Fig. 16 and has previously ..................................................

:.. ' ~' :. ., been thoroughly mixed and the contaminant is to be removed as through the use of high solubility fluids, decomposing fluids or fluids catalyzed to promote decomposition, or oxidizing agents, or reducing agents. The gas to be removed or decomposed with respect to the above-noted dis-S closure may be ozone. From this stage, an ozone-free fluid is then admitted ~o the second stage.
Although not shown in detail, the second stage may be identical to the first stage in that itcontains packed media and contains necessary tanks, lines and pumps for supplying aeration, reagents, reagent makeup 10 or medium makeup to the second stage. Once again, the treatment medium may either be high-solubility fluids, oxidizing agents or reducing agents. After the two stage treatment in the scrubber, the fluid is greatly purified and then is discharged through a blower 261. The first stage is separated from the second stage in any conventional manner 15 and may contain eliminator plates 262 which remove liquid droplets and miæt and thus prevent the liquid or treating medium in the first stage from enteFing the second stage.
A conventional washer may be utilized in lieu of a scrubber.
More specifically, it consists of three elements. Spray nozzles, scrubber 20 plates and eliminator plates. The nozzles are placed in a bank across the path of air ~ .

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lO~Z7Z5 and the water is forced through them by a pump and is dis-charged in a fine spray or mist preferably in the direction of the air flow. Counter-flow or cross-flow sprays may also be used. In some cases two or three banks of nozzles are used. The air is drawn through the washer by the fan and is thus brought into intimate contact with the water and some of the dirt and soluble gases and particulate material are re-moved. The real cleansing, however, is done by the scrubber plates which are designed to change the direction of flow so that the dirt will be thrown out of the air by its momenturn and by the rubbing of the air over the wet surface. The p:Lates are kept flooded either by the spray nozzles or by a separate row of nozzles placed above them. Following the scrubber plates is a series of eliminator plates whose function is to remove the entrained water from the air. The lower part of the washer constitutes a tank into which the water falls and from which it is taken by the circulating pump. A float valve admits fresh water as required to replace that evaporated. Provision may be made also to waste a portion of the sump tank volume through a waste line to effect discharge from the system.
Proper provision must be made in an air washer to prevent trouble from the large quantities of dirt which are washed from the air and deposited in the tank. This is one function of the ...........................................

waste line. A screen of ample area is also necessary on the suction line to the pump to prevent the dirt from being car-ried into the circulating system and in some cases epecial devices may ~e necessary to enable the spray nozzles to be cleaned periodically by flushing. The accumulated dirt must be removed from the tank at frequent intervals. In a venti-lating system where the outside temperature falls below the freezing point, it is necessary to protect the air washer from freezing either by incorporating a tempering heater ahead of it in the air stream or by utilizing an anti-freeze solu-tion in the sprays themselves. The air washer is fairly effective in cleansing the air of dust but has two other very important functions. It can be used as a humidifier or as a dehumidifier and cooler and as such iæ valuable in air condi-tioning. In the case of dehumidification it is apparent that a refrigeration element is required and in this event the spray liquid may very well be an antifreeze solution having preferen-tial solubility for the con~A inAnt gases which are of primary concern.
Whether a cross flow scrubber or a washer type scrub-ber is utilized, an alternative ~ ~c~;~qnt is to use p~Acking such as that set forth above, or the specialized packing de-scribed which include pall rings, Berl saddles, etc. wherein the hydraulic radius of the external and internal flow chAnnels are substantially the same. Such a provision is more clearly set forth in my existing U. S. Patent No. 3,730,881, issued May 1, 1974.

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~ -74-:! . . .. . .. . .

~07Z7Z5 When the fluid to be purified is contaminated with ozone as from a waste or sewage treatment plant, the ozone concentration must be reduced so that less than 1/10 parts per million parts of gas obtained from the scrubber is ozone since more than this concentration of ozone tends to be toxic.
The above described scrubber containing the packed bed having the characteristic hydraulic radii described has been found very effective in purifying, either by solubility or through a chemical reaction to or below the critical limit, 0.1 ppm O3 in fluid.
The scrubber fluid is generally different in each stage of the scrubber to effect -~i m purification. Although the scrubber may be utilized to remove or purify ozone as described, in general it can apply to the purification of any gas which is to be treated by a liquid in a fluid phase type operation. Hence, examples of other types of gases include ammonia, chlorine, hydrogen sulfide, sulfur dioxide, and the like. Depen~ing upon the nature of the gas to be removed, it may first be treated with a soluble fluid, an oxidizing agent, or a re~ucing agent. Specific examples o soluble fluids or absorbing agents which may be generally used include liquid acids having 1 to 6 carbon atoms such as acetic acid, propionic acid, aliphatic alcohols having from 1 to 8 carbon atoms such , .
as isopropyl, butyl, amyl and the like, glycol mixtures having from 2 to 10 carbon atoms such as propylene glycol, anhydrides having from 4 to 12 caron atoms such as acetic anhydride and propionic anhydride, c~r~on tetrachloride and Freons which are liquid at the operating temperature of the scrubber.

~072725 The oxidizing agents generally can include any oxidizing agent such as sulfuric acid, ethylene oxide, potassium permanganate, ~olution~
of chlorine or chlorine dioxide, ozone and air or ozone and oxygen, nitric acid, various metal dichromates, potassium perchlorate, ~ hydrogen peroxide, hydrogen peroxide in water, sodium nitrite, and the like. Of course, oxidizing agents with respect to the component of the gas to be treated are well known to those skilled in the art. Ethylene oxide is desirable for sterilization as well as with inert diluent gases (e. g. carbon dioxide, and nitrogen) to suppress explosion hazards .
- 10 Considering now the reducing agents, again a wide range of reducing compounds may be utilized in the general purification of a gas or more particularly a component of a gas phase. Specific reducing agents in-clude sulfur dioxide, a metal metabisulphite such as sodium metabisul-; phite, cesium compounds, and the like. Once again, numerous compounds which act às retucing agents with respect to the desired component of the gas to be treated are well known to those skilled in the art. Pre-ferred reducing compounds for the purification of ozone include sulfur dioxide and sodium metabisulphite.
Concerning the removal of ozone, preferably the first stage of the scrubber contains an absorbing agent and since ozone tends to be an oxidizing agent, the second stage of the scrubber is preferably a reducing agent. Usually ozone would : ' ,. - ,, :

~Oq27Z5 be eliminated in the first stage. Then the second stage could utilize chlorinated effluent or a very dilute chlorine 801u-tion which is itself deodorizing. However, the initial stage may contain a reducing agent as a treating fluid fallowed by the second stage containing a soluble fluid compound as a treating fluid. Of course, many variations can exist. Pre-ferred fluids for ozone include acetic acid, acetic anhydride, propionic acid, propionic anhydride, carbon tetrachloride, and hydrogen peroxide in water.
It should be apparent that in the use and purifica-tion of any toxic gases such as ozone in air, chlorine in air or the like, safety interlocks are to be provided throughout the entire system to prevent dangers or harmful effects upon human beings from ozone or chlorine exposure in the purifica-tion and operation areas. Moreover, the location of the ini-tial injection of the toxic gas into the treatment process is preferably remotely located from the scrubber operation for .;
safety purposes as well as being necessary for efficient in-jection mixing and for adequate contact.
FLUID-FLUID TREATMENT
According to the concepts of the present invention, a fluid but desirably a gas can also be treated or purified by treatment with fluid under conditions of high turbulence, that is, a Reynolds n ~?r of at least 3,000, to ensure ade-qu~te mixing or momentum "
.. . ... . .. ..

transfer. In general, a high turbulent purification treatment may per-tain to generally any type of gas although it is particularly suited in the purification of ozone as utiliæed in the treatment of waste treatment facilities as well as sulfur dioxide.
Referring to Fig. 17, ~purification or treatment of a gas may be carried out in a flow conduit, preferably circular, as in a pipe line, generally indicated by the numeral 301. The gas is admitted to the flow channel as indicated by the arrow and is conveyed through the channel - and exhausted. It i9 highly desirable that the Reynolds number be in excess of 3, 000 to ensure turbulence condition throughout. Preferably, to ensure that a reproducible ve locity proile is maintained when be-ginning the treatment, the grid 304 exists to produce to suppress and reduce any velocity ~;radients within the incoming gas. Typically, the grid may be made of wire, plastic or the like and may be a coarse screen. For example, it may merely be a screen grid with members on approximately one-inch centers of coarse wires having a dianleter of approxiInately 1/16 oi an inch. Of course, the size of the grid and wires may vary. The important factor is that a grid be utilized which ensures the reduction of any velocity gradients. These gradients are likely to be found in discharge sections of fans, blowers, and fittings such as elbows.
Loc.ated downstream of grid 304 is a high turbulence causing de-vice such as a flat plate orifice indicated by the numeral 306 and described herein. Generally, the turbulence causing device can be located at an elbow, union, tee or the like as previously noted. Preferably, the treating fluid is injected into the vicinity of the orifice so that rapid and thorough iX;ng quickly takes place. Desirably, this can be accom-plished through a nozzle 308 which extends into the central portion of the flat plate orifice or turbulence causing device at slightly downstream as in the vena contracta caused by the orifice. Generally, the orifice diameter ranges from about 0.7 to about 0.9 of the conduit diameter. A ;ni ratio of 0.5 may be used if high pressure drops can be accommodated.
The location of the vena contracta is usually about 0.25 to 0.5 conduit diameters downstream from the orifice plate, pre-ferably at 0.3 to 0.39 and it is at this region where the nozzle is preferably located. To further ensure thorough and complete ; ng, at least one or a second turbulence causing device may bè located downstream such as a flat plate orifice indicated by the numeral 310. The second turbulence causing device may be identica} to the first device and preferably is located downstream at least a distance of 25 to 40 conduit diameters or greater and preferably at least 40 diameters. This is to ensure that a proper length exists for adequate or thorough - mixing. The second turbulence causing device further ensures thorough mixing and hence derives the maximum contact proba-bility for efficient purification of the gas. The treated or purified gas may then be hAn~led in any conventional -nner such as by extended contact possibly followed ...............
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_79_ .... . . ............................ .
, . : . . , ~0727Z5 by exhausting to the atmosphere, by recirculation, or by the addition to a process or the like.
Although the nozzle may generally be a thin pipe or tube, a preferred nozzle is shown in Fig. 19 generally indicated by the numeral 350. Nozzle or distributor 350 generally has a first portion having an average thickness indicated by the numeral 352. Ihe diameter of the nozzle in a second portion proportionally increases until a very thin annulus 353 exists at the tip generally indicated by the arrow 354 of the distributor. The slope of the tapered portion of the distributor is genera-lly less than 7 and prelerably about 2 to about 3. A desirable thick-nexx of the annulus at the tip of the distributor is about 0. 01 inches. The diameter, as indicated, generally increases at proportional rate to accomodate pressure drop of a fluid such as a gas and moreover to en-sure good strength and rigidity of the distributor portion. Such a dis-tributor also tends to reduce the flow of the gas. Due to the provision of a very thin annulus at the tip of the nozzle, the injected fluid such as a gas is in very close vicinity to the conduit fluid and thereby tends to reduce any eddies as normally encountered with thick walled nozzles.
Moreover, additional shearing action is encountered due to the lack of eddies and thus promotes efficient and thorough mixing of the injected fluid as in the vena contracta region of a turbulence causing device such as a flat plate oFifice.

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In general, the high turbulence purification or treatment system may be applied to any type of fluid and treated with a sufficient amount of a second fluid to effect purification. Purification or treatment may be obtained by absorption or high solubility fluids, chemical reaction, or the like and involve detoxification, deodorization, and the . .
like. Additionally, the fluids may either be liquid-liquidi liquid-gas, -., .
gas-liquid, or gas-gas.
The high turbulence purification or treatment system iB
of particular significance with respect to waste or sewage treatment facilities wherein noxious or toxic gases are encountered such as ozone, ~ -~
chlorine, hydrogen sulfide, various organic odors, ammonia and the like.
~.
Thus, after sterlization or deodorization, should the fluid to be treated , . . .
comprise ozone in oxygen or ozone in air, the treating fluid may be an : ~ ~ oxidizing agent, a reducing agent, or an absorbing or high solubility ` fluid agent, as set forth above with respect to their uti1i7~tion in a cross flow scrubber or washer. Thus, an absorbant compound such as propionic acid could be added through nozzle 308 and emitted in the vena contracta portion downstream from a first flat plate orifice device with furthqr turbulence or mixing occurring at least 25 or more flow conduit diameters downstream as caused by a second flat plate orifice 310.
; ~ Similarly, as will be apparent to one skilled in the art, other compounds may be added to treat the ozone through nozzle 308. In a similar manner, sulfur dioxide may also be purified. Thus, treating fluid would be used in the scrubber.

~o7Z725 The invention will be better understood by reference to the following tables which set forth the minimum flow rate required for turbulence flow conditions or thorough mixing, Table I, for a 1uid-fluid system wherein the larger length according to either 40 seconds contact time or a transistor length of 40 diameters is utilized and similarly in Table II for a gas-liquid system w.herein turbulence causing devices such as a flat plate orifice is utilized.

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TABLE I
~,:
~TNTMT~ FLOW DESIGN PARAMETERS FOR TURBULENT
FLUID-FLUID, INJECTION - MIXING SYSTEMS
Diameter N. 8 16 24 36 50 60 Q, cfs 2.8 5.6 8.4 12.5 17.5 21.
Q, cfm(l) 167. 335. 502. 750. 1050.1256.
Length, ft. (2) 320. 160. 106. 70.7 51. 43.
Length, ft., mix ( ) 27. 53. 80. 120. 167. 200.
Velocity, ft. min 480. 240. 160. 106. 77. 64. ~
Pressure Drop, in. H2O/100 ft. .06 .0057 .0015 .00038 .000135 .000078 Pressure Drop, in. H20/Inj. Mix .35 .11 .06 .03 .01 .005 ~-Pressure Drop, in. H20/Contact Total Ozone Req'd, gm/hr. ( ) 12.8 Oxygen Req'd, cfm (5) .11 (1) Based on DV = 64 r;n; flow to ensure turbulence, D. inches, V. ft per sec.
(2) Based on 40 seconds contact time.
(3) Based on 40 D.

(4) Based on 5~ ozone in oxygen from ozonator.

(5) Based on 6 ppm ozone from oxygen in air.

TABLE II
CHARACTERISTIC DESIGN PARAMETERS
FOR OXYGEN OR AIR, GAS-LIQUID, INJECTION-MIXING SYSTEMS
- Note That Data Are For ~i n; Capacity To Ensure Turbulent Flow Diameter In. 1 2 4 6 12 18 Q min., cfs (1) .027 .054 .108 .162 .324 .486 Q gpm, 'ni 12.2 24.4 48.8 73.2 146.5 219.7 Length, ft. (2) (3) 200. 100. 50. 33.3 16.7 11.1 Length, ft., injection-mixing stage 1 12.5 25. 50. 75. 150. 225.
Velocity Min., ft.sec.-( ) 5. 2.5 1.25 0.83 .416 .28 Air Req'd., N2 sat'n., cfm(4) .030 .060 .12 .18 .36 .54 (O at 0.56 ppm) Ozone Feed, lb./day f (5) .082 .16 .33 .49 .98 1.5 Oxygen Req'd., 2 sat'n .049 .098 .196 .30 .60 1.20 I (03 at 1.25 ppm) -- Ozone Feed, lb./day .183 .37 .73 1.1 2.2 3.3 -- Pressure Drop, ft., injection-mixing stage 1.43 .68 .15 .07 .03 .005 Pressure Drop, ft., contact stage 16. 1.12 0 0 0 0 ~i Pressure Drop, ft., total 17.5 1.8 .15 .07 .03 .005 C~

(1) Based on Reynolds Number limitation for turbulent flow, DV = 5.
(2) Based on 40-seconds contact time.
--- (3) Based on 150 diameters - (4) Based on 2.5% 03 in air and a dose corresponding to nitrogen saturation which yields --- an 03 in liquld concentration of 0.56 ppm.
(5) Based on 5~ 03 in 2~ 40 ppm saturation of oxygen.

`107Z7;~ .

Table No. III sets forth data showing the execellent mixing obtained when a turbulence causing device is utilized in a conduit of a fluid-fluid system. In order to determine the extent of mixing, five samples were taken at 30 conduit diameters downstream of the location in the fluid-fluid system where water vapor (gas) was injected into air (gas) in the vena contracta portion of a flat plate orifice. The first location ; being at a radius wherein the area of the succeeding circle or annulus was equal to one quarter of the total area. The ori-~ 10 fice ratio with respect to the conduit diameter was 0.75. The -;~following data was obtained.
TABLE III

Location, R Test/R
~;~ Total 0 .354.61 .788 .g32 DBT, C 18.2 18.2 18.2 18.2 18.2 ~ ~, WBT, C 15.8 15.8 15.9 15.9 15.9 Grains llb. 72. 72. 71.1 71.1 71.1 Comp, ppm 10,286. 10,286. 10,157. 10,157. 10,157.

As readily apparent from the above data, very, very small differences in concentration were obtained at various :: .
-~ 20 locations along a radius. Additionally, the concentration .
variation was generally 1% less than the concentration average.
This table thus conclu~ively establishes that excellent mixing is obtained even after a transition length-of 30 diameters. This ' ~ !

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is in comparison with applicant' 6 preferred ; ni _ trangition length of 40 diameters which neeessarily would give better mixing. Of eourse, applieant's invention al~o relate~ to the incorporation of additional downstream turbulence causing devices to ensure thorough mixing throughout the system. More-over, it establishes that a flat plate orifiee having an ori-fice ratio of 0.75 based upon the eonduit diameter establishes good turbulence mixing conditions.
As should be apparent to one skilled in the art, many different types of fluids such as gases may be treated. Mo~e-over, a singular advantage of the in line reaetor or flow con-duit for generating chemical reactions involving gas-liquid systems is the --n~hility to variation in pressure and/or temperature in the pipe line reactor in eomparison with that which is available in reaction kettles, p~cked beds or the like.
Illustrative of industrial processes which are of importance ~ `
and which involve gas liquid reactions are the various examples set forth in "Examples of Proeesses of Industrial Importance where Gas Absorption is Aeeompanied by Chemical Reaction", Gas-Liquid Reaetions, P. V. Danekwerts, F.R.S., McGraw-Hill Series in Chemieal Engineering, 1970. An abstract of this article which sets forth illustrative examples is as follows:

'' 107'~7ZS

1. CO2, COS, H2S, C12 (i) Absorption of CO2 and C12 in aqueous solutions of barium sulphide for the manufacture of BaCO3 and BaC12, respectively; see Gupta, R.K. and M.M. Sharma: Ind. Chem. Engr. 9 (1967) Trans.
98.
(ii) Absorption of CO2 in aqueous suspensions of line for the manufacture of precipitated CaCO3;
see Morris, R.H. and E.T. Woodburn: South Afri-can Chem. Processing (June-July 1967) CP 88.
(iii) Absorption of CO2 in aqueous suspensions of MgO
for the manufacture of basic MgCO3; see (a) Shreve, R.N.: Chemical Process Industries, 3rd Ed., McGraw-Hill, 1967.
(b) Faith, W.L., D.B. Keyes, and R.L. Clark, Industrial Chemicals, 1965, 3rd ed., John Wiley and Sons, Inc., New York.
(iv) Absorption of CO2 in aqueous suspensions of CaS;
see Chem. Engng. 75 (1968) 94.
(v) Absorption of CO2 in aqueous solutions of sodium silicate; see Dalmatskya, E.J.: J. Appl. Chem.
USSR 40 (1967) 464 (Engl. Trans.) (vi) Absorption of CO2 in aqueous solutions of Na2S.
(vii) Absorption of CO2 in aqueous solutions of po-tassium carbonate of amines, for removal of CO2 from synthesis gas; see Danckwerts, P.V. and M.M. Sharma: Chem. Engr. (October 1966) CE 244 (see 10-1).

,: . ::

2. CS2 Absorption in aqueous amine solutions for the manu-facture of dithiocarbamates; see Kothari, P.J. and M.M. Sharma:
Chem. Engng. Sci. 21 (1966) 391.

3. 2 (i) Absorption of 2 in aqueous solutions of CuCl for conversion to CuC12 and copper oxychloride;
see Jhaveri, A.S. and M.M. Sharma: Chem. Engng.
Sci. 22 (1967) 1 (see 10-3) (ii) Oxidation of Na2SO3 by air or oxygen; used for establishing the charactertistics of absorption equipment (see 10-3) (iii) Air oxidation of acetaldehyde, butyraldehyde, etc., for the production of corresponding acids and acid anhydrides; see (a) Marshall Sittig: Organic Ch ; CA 1 Process Encyclopedia, Noyes Develop. Corp., U.S.A., 1967.
(b) Vrbaski, T., and I. Brihta: Arhiv. Rem.
24 (1952~ 111; C.A. 49 (1952) 163.
(c) Kostyck, N.G., Loov, S.V., Falkovski, V.B., Starkov, A.V., and N.M. Levina: Zh. Prikl.
Khim. 35 (1962) 2021, J. Appl. Chem. USSR
35 (1962) 1939 (Engl. Trans.) (iv) Oxidation of cyclohe~Ane to adipic acid; see Steeman, J.W.M., S. Kaasemaker, and P.J.
~oftijzer; 3rd European Symp. Chem. Engng. Chem.
Reaction Engng. Oxford, Pergamon Press, 1961, pp. 72-80.

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(v) Air oxidation of cumene to cumene hydroperoxide (precursor for phenol); see (a) Low, D.I.R., Canad. J. Chem. Engng. 45 (1967) 166.
(b) Maminov, O.V. et al.; Khimiya i Tkh. Topliv., Masel (1967) (12), a (Brit. Chem. Eng.
Abstract 1968 May, p. 712) (vi) Air oxidation of toluene to benzoic acid; see Faith, E.L., D.E. Keyes, and R.L. Clark:
Industrial Chemicals, 3rd Ed., 1965, John Wiley and Sons Inc, New York.
4. C12 A. Addition Chlorination (i) Reaction between C12 and C2H5 in C2H4C12 medium; see Balasubramanian, S.N., D.N.
Rihani, and L.K. Doraiswamy; Ind. Engng.
Chem. (Fundamentals) 4 (1965) 184.
(ii) Reaction between C12 and C3H6 in C3H6C12 medium; see Goldstein, R.F., Petroleum Chemica~ Industries, 2nd Ed., 1958, London, E. & F.N. Spon Limited.
(iii) Reaction between C12 and C2H2 to tetra-chloroethane; see Marshall Stittig;
Organic Chemical Process Encyclopedia, Noyes Develop. Corp., U.S.A., 1967.
(iv) Reaction between C12 and trichloroethylene to give pentachloroethane (precursor of perchloroethylene); see Goldstein, R.F.;
Petroleum Chemicals Industries, 2nd Ed., 1958, London, E. & F.N. Spon Limited.

lO'~Z725 B. Substitution Chlorination (i) Chlorination of a variety of organic com-pounds such as benzene, toluene (side chain as well as nuclear), phenals, etc. See, e.g.
Hawkins, P.S.: Trans. Instn. Chem. Engrs.
43 ~1965) T.287.
C. Miscellaneous (i) Reaction of C12 with sulfur or sulfur mono-chloride to give sulfur monochloride and i0 sulfur dichloride.
(ii) Reaction of C12 with SO2 to give sulfuryl chloride; see Kirk and Othmer: Encyclopedia of Chemical Technology, Vol. 13, 2nd Ed., ; 1967, New York, Interscience Publishers, pp.
319, 403.
(iii) Reaction of C12 with PC13 to give PC15;
see Idem., Vol. 10 (p. 477) - (iv) Reaction of C12 with FeC12 to give FeC13;
see Gilliland, E.R., R.F. ~addour, and P.L.T.
Brian: A.K. Chem. ~.J. 4 (19583 223 (see 10-2).
5. SO3 Absorption of SO3 in H2SO4 for the -nufActure of Oleum; see Duecker, W.W. and J.R. West: The manufacture of ' sulfuric acid, Re;nhold Publi.shing Corp., New York, 1959.

6. NO2 Absorption in water for the production o~ HNO3; see (a) Andrews, S.P.S. and D. Hanson: Chem. Engng. Sci. 14 (1961) .. .
105; (b) Kramers, H., M.P.P. Blind, and E. Snoeck; Chem.

Engng. Sci. 14 (1961) 115.

.

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:: ,

7. COC12 Absorption of COC12 in alkaline solutions~ see Monague, W.H. and R.L. Pigford: A.I. Chem. E.J. 6 tl960) 494.

8. H2 Hydrogenation of a variety of unsaturated organic c~ ds in the presence of catalysts; see (a) Satterfield, C.N. and T.K. Sherwood: The Role of Diffusion in Catalysis, Addison Wesley, 1963.
~; (b) DeBoer, J.H. et al.: The Mechanism of Hetero-geneous Catalysis, Amsterdam, Elsevier Publ;shing Co., 1960.

9. Deuterium -Ammonia-hydrogen process for deuterium separation, see (a) Bourke, P.J. and J.C. Lee: Trans. Instn. Chem.
Engrs. 39 (1961) 280.
(b) Bourke, P.J. and D. Pepper: Trans. Instn. Chem. ~-Engrs. 41 tl963) 40.

10. Olefins -~
(i) Absorption of isobutylene in aqueous solutions of H25O4 for the manufacture of tertiary butanol and for poly-merization to di-iso and tri-isobutylene; see Gehlwat, J.K.
and M.M. Sharma; Chem. Engng. Sci. 23 (1968) 738.
(ii) Absorption of isobutylene in phenols and sub-stituted phenols in the presence of H2SO4 as a catalyst for the manufacture of the correspon~ing alkylated products;

.

., --91--(a) DeJong, J.I.: Rec. Trav. Chem. 83 (1964) 469.
(b) Whitney, W.: Ind. Bng. Chem. 35 (1943) 264.
(c) Jelinek, J.: Chem. Prumysl 9 (1959) 398; C.A.
54 (1960) 8696.
(iii) Absorption of but~ ne in cuprous ammonium complexes; see Morrell et al., Trans. A.I. Chem. E. 42 (1946) 473.
(iv) Absorption of butenes in sulfuric acid for con-version to secondary butanol; see Rustanov, K.R. and N.M.
Chirkov: Zhur. Fiz. Khim. 30 (1956) 261; C.A. 50 (1956) 11081.
(v) Absorption of acetylene in aqueous CuCl solutions to convert it to vinyl acetylene; see Marshall Sittig: Organic Chemical Process Encyclopedia, Noyes Develp. Corp., U.S.A. 1967.
(vi) Absorption of ethylene in benzene to produce ethyl benzene using AlC13 catalyst; see Marshall Sittig:
Organic Chemical Process Encyclopedia, Noyes Develop. Corp., U.S.A. 1967.
(vii) Absorption of acetylene in arsenic trichloride dissolved in C2H2C14 for the manufacture of chlorovinyldichloro-arsine; see Whitt, F.R.: Brit. Chem. Eng. 12 (1967) 554.

:. .
: ' ' ~ ' " ';
, ,. . . ~ . .

-~0727ZS

(viii) Absorption of ethylene in sulfor mono- or dichloride dissolved in benzylchloride for the manufacture of dichlorodiethysulfide; see Whitt, F.R.: Brit. Chem. Eng. 12 (i967) 554. (Some other examples are also given in this paper).
1 1 . SO2 (i) Absorption of S02 in aqueous solutions of NaHS03 and Na2S03 in the presence of zinc dust to manufacture dithio-nite; see Suzuki, E., EØ Shima, and S. Yagi: Kogyo Kagaku Zasshi 69 (1966) 1841.
10(ii) Reduction of S02 in S03 = /HS03 - buffer by NaHg amalgam.
(iii) Absorption of S02 in aqueous solutions of NaN02 and zinc dust for the manufacture of hydroxylamine.
12~ HCl and HBr (i) Absorption of HC1 and HBr in higher alcohols for the manufacture of the correspon~ing alkyl halide (e.g. lauryl ~;~ alcohol to lauryl chloride or bL~ e); see Kingsley, H.E.
and H. Bliss, Ind. Eng. Chem. 44 (1952) 2479.
(ii) Addition of HBr to alpha-olefins for the manu-2:0 facture of alkyl bromide (with terminal bromine atom), e.g.methyl undecylenate reacting with HBr.
(iii) Addition of HCl to vinyl acetylene for the manufacture of chloroprene.

.

`` 107Z7ZS

In lieu of a conduit having multiple turbulence causing devices therein, additional embodiments include abruptly changing the diameter of a pipe or flow conduit as well as the provision of a mani-fold takeoff. Either of these will help to reduce the total system length otherwise required for thorough mixing and hence greatly reduce the physical space required. Considering the abrupt diameter change, a turbulence causing device such as a flat plate orifice is preferably located at the end of a constant diameter pipe which is connected to a constant diameter pipe or flow channel of a larger diameter. For ex-ample, a 4 foot pipe with a flat plate orifice at the end thereof of diameter ratio sufficient to remove the boundary layer fully may be connected to a 7 or 8 foot diameter pipe. Such an orifice at an abrupt change in diameter ensures thorough mixing and hence suppression of any radial concentration gradients. In such a situation, any subsequent downstream turbulence causing device being at a distance of at least 40 pipe or conduit diameters.
Considering the manifold arrangement, it consists of a pipe or flow conduit which is abruptly converted into several pipes of smaller diameter with a larger overall total conduit flow area if it is desired to maintain the same pressure drop per foot as to the large conduit. For example, a single 4 foot diameter pipe may be abruptly transitioned by manifolding into 24 one foot diameter pipes.
The first turbulence causing device such as a flat plate _94 ., `'; :'`.`. " :

orifice is preferably located in eaeh manifold relatively near the conversion from a single pipe into the multiple pipes.
Aceording to such an embodiment, the transition length may be reduced from 40 diameters, i.e. 40 x 4 feet to 40 x 1 foot, a reduetion of 120 eet. Of course, other turbulence causing devices may be located downstream as before.
Regardless of type of alternate embodiment in point, the admission of a treating fluid may be carried out in accor-dance with the above set forth disclosure.
In the conveying of fluid from one area of the system such as a treating portion to another area, the diameter of the flow ch~nnels may be changed, as desired. Fox gradual transi-tions to deeelerate subsonic flow, the diffusex transition should not exeeed a slope of approximately 7 to ensure that boundary layer separation is suppressed. This slope is not eritieal for transition nozzles which accelerate subsonic flow.
Preferably, following a fluid phase treatment station, ineluding downstream mixing as through second or third turbu-lenee eausing devices, a contaet ch~ r may be provided. The purpose of such a eh '-?r is to extend the detention time of the treated fluid after ideal mixing has been developed.
; OZONE PRODUCTION
According to the concepts of the present invention, an .. : . , ~ .

improved process for the produation of ozone may be utilized.
In general, an ozonator requires a feed of ~ygen containing gas, a voltage potential and a ~ n~ amount of pressure.
Upon application of the voltage, oxygen in the feed gas which is under pressure is partially converted to ozone. It is known that the production of ozone can be oxir;zed at high gas feed rates. These yield relatively low ozone in gas concentrations.
It is also known that ozone can be produced by varying the feed rate of oxygen and the voltage. It has been found that this can be done in such a way so as to -x;~;ze the ozone co~ce~tra-tion which may be dissolved in a treated fluid. To do this requires a departure from standard teaching. A sacrifice is ~ required in the electrical energy consumption in kilowatt hours ;~ per pound of ozone produced. Specifically, the feed or amount of oxygen containing gas fed into the ozonator is reduced to the i ni required amount and the voltage is increased to the maximum amount possible with the particular unit. The ef-fect is to obtain less than maximum or rated ozone production.
However, this sacrifice in ozone production is more than offset by a gain in efficiency of gas liquid injection and mixing derivable in the following step. This mode of opera-tion of an ozonator enhances ozonation by allowing higher ozone concentrations in a treated fluid within the limit of the satu-ration quantity of any component of the carrier gas in the :

10 ~ 7~S ~

treated fluid. For example, an air feed, an ozone concentra-tion of 2.5% is possible. From air, the nitrogen solubility in water i8 18 ppm. The air feed is proportioned to provide this quantity of nitrogen. The quantity would be 22.5 ppm of air, of which 2.5% would be ozone. The 02 and 03 fed would stabilize at 4.5 ppm unless oxidation reactions deplete the !
ozone. The correspo~;ng ozone concentration in the treated fluid would be 0.56 ppm. Ozone-fluid solutions are bacterici-dai and viricidal at ozone concentrations of O.S ppm or greater.
O Thus, this technique achieves disinfection without entailing an Inherent 10ss of ozone in gas blown through~the fluid sys-tem owing to gas-fluid saturation in the treated fluid. It should be recognized that gas feeds~at rates above these cor-responding to saturation of any gas component in the fluid will and~mu-t be followed by gas~blow through. In blow through, ozone~and non-saturated c ~n~nts of gas will be lost. It `follows that the operatingiprinciple is to feed gas or gas mixtures~at the lowèst possible rate,~pr-ferably at component ga6~saturation 1imits or less. Potential loss of osone from 20- inef~f~icient gas-fluid mixing is many~times greater than the 1088 in~ozone productive capacity lr.d~ced by ozonator operation at maximum practiaal ozone in oxygen con~Aining gas concentra-tioni3~ P~oo~n1zing~this~ it follows that ozonator improve-ments focused on sus~A;n;ng hwh/pound of ozone pro~uce~ at maximum poss;ble ozone conc~trations in oxygen containing gas , ~ -97-: -~: :
.. ~, . ... . . .. . . . . . . .

107'~725 are most desirable. The ozone, of course, can be used in anysubsequent process such as in sewage or waste treatment plants hereinabove described as well as for any other conventional uses. The important factor is that the process only requires the smallest possible amount of oxygen as feed so that upon the application of the voltage, a -~i concentration and amount of ozone is produced.
OZONATOR CHARACTERISTICS
Production Rate. The production rate of an ozonator depends primarily upon the applied energy~ Operating controls usually provide for a broad range of input gas flow. The gas must contain oxygen. An increase in oxygen concentration to twice that for air approximately doubles the ozonator produc-tion rate. For a 100% oxygen feed, little increase in produc-tion rate is observed above that for oxygen-enriched air at 40 oxygen concentration.
As the gas feed rate to an ozonator increases, the ozone concentration in the ozonated output flow decreases. The decrease is almost exactly inversely proportional to the input input gas feed rate. Thus, for a gas feed rate Wg in pounds per minute and an ozone concentration, C, in parts per million, in the output gas, the ozonator production rate WO in pounds per minute is almost a constant. This is shown in the Fig. 30.
Note there that the volumetric feed rate is used instead of the weightfeed rate. However, the relationship on log-log coordinates is almost linear. The relationship, Wg . C = WO
as defined before, would plot as a straight line. The dotted line illustrates this relationship.

, `~ 10'7~ 7~5 The illustration also shows how a reduction in energy supplied to the ozonator can reduae the production rate of ozone. Practicably, this is the only control on ozone output except for a change in oxygen enrichment of the ozonator feed gas.
Fig. 36 also shows energy requirements for ozonation only. Additional energy is required to dry and compress the ozonator~feed gas~ From pr~ae~;ng discussion, it is apparent that axi~ ozone production occurs near the mid-range of any lO~ plot.~ However, ozone produation at the lowest range of any plot is not materially less than that for the maximum condition.
Th1s`lowest range of gas feed rate corresponds to the maximum ozone concentration. Elsewhere in this specification, it has bèen~indicated that gas-lqiuid-mixing efficiency is potentially greàtest ae~the highest ozonator ou~pu~ ozone concentration achievable.~Thus,~ overall~ozone-applied efficiency is deri-," . ., ~
vabie~by~ozonàtor operation at m;n1-` gas flow eed rates.
Th~es- compromise ozone~production slightly. ~ The c _. ise is more~;~thàn compensated for by the improved injection i~;ng 20~ ;eficiency.
~a~ ' Further, under this rec~-r ~ ed mode of operation, the totali-nergy~required per poùnd~of ozone generated and ~'''`'?~ ' applied within the overall system is reduced. This is so owing to the~~rkP~ reduction in $eed gas drying and compres-sing energy which is necess~ry at minimized ozonator gas feed rates. One actor whiCh contributes to this ortuitous cir-cumstance is the moderate efect of nitrogen in ozonator feed , ~
gas on production rate. To about 60% nitrogen in oxygen o ~ the feed gas, nitrogen does not materially degrade the ozone :~ `30 production rate.

_99_ . ~,;

:lO~Z725 It is useful to consider the comparative perfoL -nce of an ozonator on oxygen enriched air feed at the recc- n~ed low gas feed rate with that for the normal flow rate. The comparative ozone concentrations are 55. mg/l and 25. mg/l.
These correspond to ozone concentrations in the ozonated gas output of 4.6% and 2.1% respectively.
This comparison appears in the table which follows.
There, the production rate column shows that ozone output is slightly greater at the relatively low ozone concentration of 2.1%, 25. mg/l. This occurs at the highest feed gas rate.
The specific energy column reveals that this high gas rate ; corresponds to high energy penalties for drying and compressing the ozonator feed gas.
Compare these conditions with those for production at 55. mg/l, or 4.6% ozone concentration in the ozonator output.
There, the lowest ozonator feed gas rates prevail. At 200 watts, the ozone production rate is 14.6 g/h at low gas rates.
It is 17.3 at the high gas feed rates. This is a reduction of ,~ .
about 16%. However, the specific energy for the low gas rate is 8.5 kwh/lb. The high gas rate exhibits a specific energy of 11.3 kwh/lb. The reduction in specific energy is 25%. It is logical therefore to sacrifice 16% in rated production for a 25% saving in energy.
-In addition to this economic advantage, the high ozone concentration enables markedly increased ozone input to the treated fluid. Thus, the overall system efficiency is increased greatly while the energy requirement is reduced 25%.
Finally, the oxygen-enriched air feed gas contributes Lr, co x Ln u~ I~ I~ O ~ o oo u~
...............

I r~
~1 n ~.
.
.
t . ~ o In~ ~ o O
~n U~
e~ ~ o o o coIn ~ O ~ O1`1`In ~ ~ ~.
~rC
~ X
L: ~
U~

.
~3 ~. . . . . . . . . . . . . .
Z;
~;
O r, ~;
o O ~
~3 ~r -'I O O OO o O O o O o o o o O O o ~; I O ~D ~CO O ~ O~D~`I000 ~ ~ ~
r~ 1r lr I ~r lr l ~ r l r l -I a, u~ r ~ ooo N ~ ~r ~ Oa~ ~(~ 00 CO
u~ o ~') ~ co oo o a~ o 1~ o P r l N ~ r~l ~ ~ ~ r~ ~ ~ ~ ~ r l r l r ~.>`
r r W
~a ~ ~r ~ ~ ~ O

-~07Z725 further advantages. Oxygen enrichment at 40% oxygen, 60% ni-trogen almost doubles ozonator production compared to produc-tion on air.
Less oxygen enrichment is proportionately beneficial.
One particular enrichment is of interest. In this specification, it has been noted that air-saturated water exhibits a dissolved gas distribution of one part oxygen to two parts nitrogen. This has shifted from the input gas distribution, in air, of one part oxygen to four parts nitrogen.
It might be expected that oxygen enrichment of air to 33% oxygen, 66~ nitrogen would be in equilibrium with the one to two ratio noted above. This is not so. As the oxygen con-centration in the fluid saturating gas increases so does the oxygen concentration in the dissolved gas. For this reason, the preferred range o oxygen-enriched air feed for ozonation is from one-third to two-fifths oxygen.
Under these condition, recycling of the desorbed :::
~ozonated carrier gas is possible at in; um oxygen feeds to sustain desired enrichment of feed gas. This mode of ozonator operation, i.e. low feed gas, flow, recycling, high ozone con-centration and oxygen enrichment of air feed comprises the optimum overall system for generating and dissolving ozone in treated fluids. These system operating conditions are optimum in terms of overall cost of ozonation per unit weight of ozone dissolved in the treating fluid.
In the foregoing system, small quantities of oxygen makeup may be required. This may be supplied from on-site oxygen generators, from LOX storage or from gas-phase storage.
Since the equilibrium concentrations ...... ~

~' 1(~72725 of dissolved gas in air-saturated water are 33% oxygen, 66% nitrogen an alternative source of makeup feed gas is possible. Pressurized water is saturated with air. The saturated water i9 decompres~ed. Desorbed gases are recovered. These gases will be comprised of 33% oxygen and 66% nitrogen. They represent a near ideal ozonator feed gas. This feed gas could be enriched with oxygen, if desired.
A typical system for the production of ozone is shown in Fig. 37. Numeral 710 is a compressor which feeds the fluid, prefera-bly air through a length of piping containing turbulent producing devices to insure complete mixing such as flat plate orifices set forth above separated by at least 40 pipe diameters. The fluid is then held in a high pressure tank 715 which contains an atmosphere rich in nitrogen.
The fluid is then fed through an expansion valve 716 which may be a hydraulic turbine generator to recover energy in the form of eléctrical or mechanical energy to a low pressure desorber 720 which contains an atmosphere rich in nitrogen. Each tank contains water. Part of the water from the second or low pressure desorber is recycled through a pump 721 and pipe 722. The air or fluid is then fed via line 723 to dryer 725 which may be silica beds wherein the air is alternately fed to one tank and not the other. This procedure is generally preferred to drying by refrigeration below the dew point. With respect to the liquid in `
tank 715 and 720, water may be utilized as noted but generally any liquid having higher solubility for oxygen than nitrogen may also be utilized. The air`, after drying, is then fed to an ozonator as herein-above described via pipeline 728. The fluid containing a high concentra-tion of ozone is then fed to a contact tank 740 via a pipeline 735 wherein mixing devices are contained auch as flat plate orifices. After the contact tank, part of the gas or fluid is recycled to the dryer whereas the liquid in the contact tank such as water may be pumped out at will.

- 1 03a-.. .
; '. ' '' ROTARY DISTRIBUTOR ARM AND NOZZLE
FOR TRICKLING FILTER
In a trickling filter, the bed beneath the distributor arm should be dosed with liquid at a uniform flow over its area, expressed in gallons per square foot per day. A usual -~;
rate is 1,000 gallons per squa~e foot per day. It is necessary for efficiency and economy of operation that the dose rate be uniform with radius at any impressed total flow on the system.
The reason for this is that at any impressed flow rate, the flow from the distributor must dose the trickling filter media with equal quantities of flow per~square foot of surface. 5ince the :
surface of the filter goes up as the square of the radius it is underst~n~h~e that the flow is going to have to go up quite a ~-bit at the outside edge. Unless some provision is made for chAnnçling the flow, the tendency in an actual operating filter is to make the flow distri~ution speed dependent. This will tend to unwater the central section of the arms and to shift major flow towards the outer radii of the distributor arm. It is particularly a problem to insure uniform flow at low flow 20 rates. ..

.. . .

~: .
:::

~ -104-, . . . ,, , , : , ~07;~7~S

Now referring particularly to Figs. 20 - 23 of the drawings, the distributor arm is indicated by numeral 399. A
dotted line 400, as seen in Fig. 22 runs down the centerline of arm 399, and this represents a closure which isolates a ch~nnel allowing only half the total chAnnel to be available for flow in the filter distribution arm for a lower portion of the section. Fig. 25 better shows the cross-sectional configu-ration, and clearly indicates the divider section 400, as well as a horizontal divider section 402 which will be discussed in further detail hereinafter. Note in Fig. 25 that the upper surface of divider 402 is at substantially the same level as ~ the centerline 404 of the orifice opening 405 (orifice 410 not ; shown in Fig. 25). The orifice locations are present in the -~; number for which space is available and they allow effluent to be removed from the distributor arm.
Now with reference to Fig. 25, the construction is provided to isolate the flow of effluent until the level builds up to the top surface of divider 402. First in considering this buildup of level, it must be assumed that flow occurs at a variable rate as it i8 distributed by the distributor arm.
This flow rate depends on the rotative speed of the distributor .
arm. A usual maximum rate is 1,000 gallons per square foot per day. However, by doubling the width of the channel above ` the divider 402, ............................................

, ; -105-. ~
. ., , . . .: . .

:
~: 107Z7z5 what has been achieved is in effect allowing a further increase in flow to occur with a reduced change in level on the dis-charge orifice. This reduces the range in one variable. Other means that may be used to vary the distribution rate are to vary independe~tly the diffusing nozzle to improve control of thrust, speed of rotation and diffuser flow such that the dose rate is uniform within the radius at any impressed total flow. Hence, , "~; unless some provision is made for chAnneling the flow, the tendency in an actual operating filter is to make the flow distribution speed ~ep~n~ent. Therefore, I have found that by block;ng off the lower part of the section by divider 402, the flow at low rate is insured and it reduces the effect of in-creased flow at high rates by accommodating it with a _ ~lle-r change head.
An additional feature of the distributor arm 339 which;~is interesting is that its diffusing orifices indicated g-nerally~by numerals 410~and shown in Fig. 24 are positioned ; ;~
;at~various~locations along the length of the distribution arm 1n~F1gs.~ 22~and 23,~are variable in elevation, that is, by 20~ ~rotation, the flow pAssAgQ can be modified by rotating the orifice.~ In this way, dere~ding on orifice configuration, ro-tation may be used to vary the head and flow or momentum chAnge.
The~mcmentum change develops thrust. This effects distributor speed. Sp ed effects the~head along the distributor radius.
Thus~it is important to be able to change head, flow and changes in an orifice indep ndently, and the orifices ' ~:: ~ ..

~:

.~'','~';''.'.' ' ":"'' ''""'','' ,' ' ' ,''' '',,.''.'""' ;' '. ' '"' ' ` .' 210 as seen in Fig. 28 incorporate a hex nut 212 to allow the orifices to be mechanically ~twisted to vary the directlon of their thrust.
Figs. 29 and 3a represent a modified orifice com-prising a 90 elbow. This may again be rotated by means of the hex nut 212a either using a wrench or hand pressure. It may be rotated to discharge vertically upward or downward. The head and flow would thereby be varied greatly. The change in ~ -ntum would be a function of the velocity of the liquid, as 10 well as the angular position of the orifice.
Again referring to Fig. 28, each nozzle 210 incorpo-rates a slot 214 milled into a circular pipe section 216 com-prising the nozzle. Further, an end cap 218 has a slot 220 cut therein so that in effect two separate slots for control purposes are available. Preferably the slot 220 is elongated and~circular on the ends but as it can be seen it is eccentri-cally offset from the centerline 222. Thus by rotating the slot 214 upwardly, the flow is reduced because the head is reduced. In this instance as shown in Fig. 28 you could have r 20 a lot of flow coming out the slot 220, but none coming out of the slot 214. Now again looking at the slot 214, if this is rotated down, then the slot 220 in the end of the cap will be .::
rotated up so that there is no flow directly out the end of the cap, but all or substantially all of the flow drops down onto the filter bed from the slot 214 in the short nipple section of the nozzle. Considering the desire to change indep~ndently the relative flow and the propulsive , .. . . ,..... .,.............. . , ~,, ... , .. . ~ -effort at the same time, this is possible by mutual changes in the angular settings of the two rotatable elements, namely, cap 218 and nut 212 and pipe section 216 which comprise the nozzle 210.
The rotation of the nozzle elements can be done manually, but most conveniently, it can be done using an appropriate wrench.
Primarily the idea of adjusting the angular position of the `
slots for flow control is to accommodate changes in flow which occur progressively on a plant, usually towards an increasing flow, which would occur over a long period of time, rather than daily incremental changes without effecting the radial uniformity of dose to the filter bed.
It must also be understood that the speed of the distribu-tor arm is important in that the distributor rotates by reason of propulsive effort. As the speed changes, an effect on the pressure distribution in the distributor arm occurs. This is apparent from the fact that the liquid surface in a rotating vessel is paraboloidal. Thus, the virtual head approaching the distal tip of the distributor is hi:gher than that at the center by the difference in magnitude of the paraboloidal ordinates. The general effect of the increased head towards the distal tip of the arms would be to increase the flow dispro-portionately in the region. This is one reason why I have determined to take the measures with respect to the nozzle slots to control the rotative speed of the distributor, and also .. ,, - ~
. :.
, the measures to control the flow channel as seen in Fig. 25, which was discussed above. Therefore, this distributor in the embodiment shown in these drawings will accommodate with independent means and provide the adjustment necessary to achieve the basic objectives of making uniform over the range and radius the proper flow distribution per unit area of receiving media below the arm.
As a further result the rotatable cap 418 facilitates cleaning of material which may become entrained in the orifices or slots 414 and 420. It should be noted with respect to Fig.
24 that the nozzles 410 are actually placed in the closest pos-sible spacing such that you can -~;~;ze the number of slots or orifices which are inserted into an arm.
A further point that should be noted with respect to Figs. 20 - 23 is that the nozzles appear on the upstream face of the distributor arm as well as on the downstream face, and this is seen in Figs. 22 and 23. The purpose of the upstream orifices or nozzles is to enable further control over the pro-pulsive effort and the speed which is developed in the distri-butor without compromising the uniformity of flow dosage perunit area of receiving media beneath the filter.
Another possibility with the type of distributor arm defined above is to insert instead of spray head nozzles such as shown in Fig. 28, some type of closure plug which in this way adjuststhe flow independently of the orifices. That is, by removing nozzles and placing in a substitute blanking nozzle, which is a standard pipe plug, tbe flow can be controlled.

... . .. .

A further detail in the construction of the distri-butor is a vent to prevent the formation of a vacuum. Such vents 430 are shown in Figs. 22 and 23.
A further feature of the structural requirements of the arm is to have tie rods indicated generally by the çh~nnel 432 and best seen in Figs. 20 and 21 extending from various points along the length of the arms back to the central support post 434 to support the arms in cantilevered fashion from the central distributing head 436. Such tie rods 432 compensate for horizontal forces which occur by reason of an acceleration or deceleration, and the sbructure o the arms themselves is that they function as a variable section-modulus beam from zero radius to the radius of the distal tip so that they are suppor-ted at independent points by the rods 432 which are adjustable so that the distributor may be trimmed when it is ins~alled to operate in a horizontal plane without a stress which would occur with a cantilevered arm.
`The multiplicity of tie rods and the stress analysis of such a distributor is based on approximations concerning intermediate structures involving a continuous beam supported - on three inte ?~i Ate supports. It can be utilized analyti-cally at least as a first approximation as a constant section beam. Subsequently the analysis needs to be-refined-for chec-king. It should be strongly pointed out and is clear from the drawings that the section-modu1us varies continuously along the length of these arms from a larger cross-sectional configu-ration near to the hub 436 to a much smaller cross-sectional configuration at the distal tip, and hence the section-modulus and the stress analysis needs to be made more sophisticated to ..
. . ~ ~, .- . . .
.. . . .

" 107Z7Z5 accommodate the variation in section-modulus as a function of radius of the distributor. In other words it is a feature of the invention that the arms are tapered or decrease in cross-sectional area all the way along the whole length uniformly.
The tapered configuration to the arms makes them less sensitive to changes in rotative speed of the distributor and to short term changes in distributor flow, and pronounces the effect of getting a greater volume flow out the nozzles the further they are away from the center of the hub because it is that area of the filter medium that needs a greater flow because a greater area is being covered the further they are away from the center of the hub. r Now again referring to the cross-sectional configura-tion of the arm which is substantially rectangular as seen in . ~ ~
Fig. 25, the divider web 400 furthermore serves as a reinforce-ment between the upper and lower flanges 401 and 403 of the distributor arm which functions as a stiffening beam web. Note that the web 400 is interrupted periodically with holes through it such as at 405. These holes 405 a}low fluid to enter into ~the upper ch~n~el of the blocked off section as well as in the normal ç~hA~nn~l.
Now referring particularly to Fig. 26, this represents the same cross-sectional configuration of Fig. 25 except sub-stantially doubled in heigth with the blocked off regions 440 and 442 blocked in both the upper and lower chAnnels. The upper h~nnel (overload flow chAnnel ) iS separated from the lower chAnnel (normal flow chAnn~l) by a horizontal divider 443. The intention here is to have the upper section function under high conditions of plant flow ............. ~

:

, . . , .. .: .

3~7Z7ZS
and insure the proper distribution of flow along the radius of the distributor regardless of the level of flow. One must be particularly careful about how this is occurring in that an extremely high flow rate would normally make a trickling filter distributor rotate excessively fast. High speed would throw the liquid out to the outside radii of the distributor making the flow distribution through the media not a unifor~
flow per unit of surface area exposed. With the embodiments shown in Fig. 26, however, this distributor section would maintain approximately the same width-to-height ratio in the cross-section as in Fig. 25 for the normal distributor. In other words, the height and width ratio would be the same in the double channel distributor arm as in the single channel.
In order to understand how the double channel or overload flow configuration of Fig. 26 would work, reference should be made to Fig. 27 where the numeral 435 represents the central column of the trickling filter with flow coming in as indicated by the arrow 450. The normal flow for the effluent will be directly into the normal flow channel of the distributor arm or as indicated by arrow 452. However, when the flow builds up over the weir-type pipe section 454, overflow will occur in the direction of the arrow 456, and thence down into the overload flow channel of the distributor arm as clearly shown in Fig. 27. The weir equation that is pertinent is Q = 3.33 x c x H3/2 ft. The sketch of the cfs ft.
diagram of Fig. 27 indicates ho which is the weir head eleva-tion of the weir with no flow over it. Basically, the above equation gives the weir flow which would be accommodated in the upper channel when the flow overflows the overflow weir.
The flow then in the lower channel or the normal flow channel A

` 107Z7Z5 would then increase less at any leveI of flow beyond that cut-off for the particulary head ho. After the head ho is rePcheA, the overflow of the weir all would pa8s into the upper or over-flow ch~nnel in quantities or at flow rates as given by the equation. The head on the weir would be the actual head of water level of the edge of the weir which is marked on Fig. 27 as hl -~ning the head of the liquid, in feet.
Hence, in summary, the flow in the rotating distribu-tor arm is governed by two things. These are the nozzles that are present and the rotative speed of the distributor. These are the only factors that influence the pressure distribution along the length of the arm. So this method of controlling an overflow and ch~nnelling it into the upper level of a two level distributor with the same tapered configuration to the beam ` ; ;~ cross-section as clearly shown in the enlarged Figures 20 - 23 can function on a single level or a double level distributor arm.
Referring again to the alternate sweep elbow of Figs.
~: ~
29 and 29A, the distance e in Fig. 29 represents the displace-~h 20 ment of the end of the nozzle from the centerline of input to ::
indicate that rotation of the nozzle will change the head.
It should also be seen as shown in Fig. 29A that the i; end of the nozzle at 460 is flattened to spread the flow of fluid upon discharge from the nozzle to accomplish an overlap in the falling streams of adjacent nozzles.
The graph of Fig. 30 illustrates a curve 470 with the ordinate representing the percent of turbidity and the abscissa representing concentration levels of polyelectrolyte .:: . . , : .. ,. :... -:, feed. This curve therefore shows the optimum concentration of polyelectrolyte feed for r~;mllm removal of su~pended mat-ter. This is important with respect to the further operative ;`
embodiments of my system which utilizes polyelectrolyte feed for removal of suspended matter.
INJECTION MIXING SYSTEM WITH CONTACT TANK
The injection mixing system with a contact tank isseen in Figs. 31 - 34 of the drawings. With reference to these figures, the numeral 500 indicates generally a large contact tank of substantially rectangular section which incor-porates an influent trough 502 as best seen in Fig. 32, a contact tank or trough 504 and an effluent trough 506. An influent pipe 508 directsinfluent into a bundle of pipes in-dicated generally by numeral 510 through an appropriate valve manifold arrangement indicated generally by numeral 512. The pipe bundle 510 receives the influent from the pipe 508 and first of all passes the influent through a respective injection mixing elbow 514, as best seen in Fig. 34, and described more fully hereinafter, and thence through downstream flat plate ; 20 mixing orifices 516 and 518, and thence to the influent trough ` 502 for discharge thereinto through a hypobolic transformed diffuser 520. The flow from the influent trough 502 into the contact ch. ~r 504 is by appropriate sluice gates 522, as controlled by an operator station 524 as understood by those skilled in the art. The flow from the contact tank 504 into the effluent trough 506 is past an overflow weir 526.

. .:

-The details of the injection mixing eIbow 514, as seen in Fig. 34 comprises a 90 pipe elbow 530 with a flat plate orifice 532 connected at the downstream end of the pipe separate between the flanges between the eIbow 530 and the next downstream pipe section 534. In order to achieve effi-cient mixing of ozone for example as a typical disinfection medium, injection is achieved through an injection tube 536 positioned on the axis of flow of pipe 534 but extending from the elbow 530 as illustrated in Fig. 34, this type of injection mixing being described in my above-identified earlier patents.
The flow is indicated by arrows 538.
Because of the system parameters for which the par-ticular injection mixing system shown in Figs. 31 - 34 was ~; designed, the influent pipe 508 was a 48" diameter duct and it was manifolded into twelve indepen~nt lines indicated by ~ -the pipe handle 510. It is to be noted that the manifold is ~; approximately 4' 6" off the floor of the contact tank 504, and the pipe bundle 510 are comprised of 12-inch diameter pipe proposed to be made of polyvinyl chloride. They are located Z0 12 inches off their centerline above the floor of the tank.
In addition to the injection i~; ng orifice in the ;
injection mixing elbow 514 as described above, there are 50 feet downstream which is 50 diameters of the pipe (anything in excess of 40 diameters being preferred) subsequent flat plate mixing orifices 516 and 518 are provided.
The influent then after having a full injection mix-ing through elbow 512 and flat plate orifices 516 and 518 has a ~0727Z5 ;`
t`horough concentration of ozone or any other injected medium, ànd thence the flow proceeds to the normal influent trough location 502 at the end of the contaat tank. The influent mixing lines move vertically up through the contact chamber 504 and traverse the wall between the influent trough and the contact tank. At the bottom edge of the injection mixing pi-ping, the flow out into the influent trough 502 is through the hyperbolic transform diffuser 520, which directs flow out-ward from the pipeline onto the wall, and which generates a ~; I0 hyperbolic sheet on the wall with mixing of the material pre-sently in the influent trough 502. The resultant mixed product then traverses the sluice gates 522 into each of the four independent chAnnels as divided by the divider walls 504a, and best seen in Fig. 31, in the contact tank 504.
The effluent trough 506 discharges to a 6' diameter effluent pipe 560 as seen in Figs. 31 and 32. It should also be understood that sampling connections may be made on the pipe b~n~l e 510 for the sampling of dissolved oxygen and pressure.
Normally, the effluent channel itself would be sampled for dis-solved oxygen and/or for biological testing to confirm theabsence of fecal coliforms in excess of specification require-ments. A typical specification requirement might be 200 fecal coliforms per 1`00 ml. This is a very high level and it is possible to achieve less than 2 fecal coliforms per 100 ml utilizing a one percent concentration ozone injection at elbows 512.
Referring again to the hyperbolic difuser S20, it should be understood that this section is a transformed hyper-bolic section which decelerates the flow. The flow impinges on the influent trough wall where it mixes with the trough contents before the mixture passes through the sluice gates of the influent trough and into the contact tank proper. The diffuser 520 actually increases in area along the flow path and the elbow section in such a way as to decelerate the flow.
The deceleration is intentional and is intended to produce a hyperbolic sheet on the impinging wall. The diffuser should not diverge more than 7 in the channel, otherwise boundary layer separation will occur. However, for practical economic reasons it is more convenient to use a conventional elbow dif-fuser instead of fabricating a special piece of equipment for this purpose. It should be understood that most of the necess~ry injection mixing and contact-has occurred in pre-ce~ing sections of the 12" diameter lines i.e. the pipe bundle S10, which are the actual elements utilized for injection mixing, and contact of whatever disinfectant which is used, which~may be either the ozone systems described previously, or chIorine solutions in water.
In the configuration described above with reference to Figs. 31 - 34, the number of elements passing through the contact tank in an actual system design was proportioned on the basis of an available head o 12 1/2 pounds per square inch, which corresponds to approximately 26' of water. Of the available 26' of water head, 16' of water was utilized in the actual pressure drop in the 12" pipes, of which there are 12, in the condition where the flow is -xi for the plant. The m~;m-lr design flow for this configuration is one hundred million gallons per day. Thus, the pressure drop i8 a rela-tively conservative figure under the circumstances and the pressure excess is available because this is a physical treat-ment plant. Where the pressure drop might be more conserva-tive, the pressure could be controlled and a reduction in the number of pipes would be possible, that is in the 12 elements of pipe, by changing the diameter from, for example, 12", up to perhaps 16" or larger. But, consideration must be given to the necessity of having preferably at least 40 diameters between mixing orifices so that the overall system length i5 of the order of 120 to 150 diameters.
A further limitation and consideration that must be incorporated into all plant designs is a possible requirement for de-oxygenation of the final effluent. This can be done in a number of ways. One way would be to inject sulfur dioxide, which would de-oxidize the ozone or chlorine in the final effluent, and would furtharmore remove the oxygen excess present. A second possibility is to use thiosulfate, a chemi-cal reagent which destroys ozone and/or chlorine and willreduce the oxygen concentrations. A third possibility would be to use a mechanical type de-aerator, such as a Cochrane Feed-Water Heater De-Aerator, used conventionally on boiler feedwater systems. The dissolved oxygen specification ~x;r~lm for this design is presently at a no~;n~l value of 20 milli-grams per liter. This would either restrict the ozone capa-city available for feed, or would require de-oxygenation by the means set forth above.

`` 107Z725 ACTIVATED SLUDGE AERATION SYSTEM
Fig. 35 illustrates an activated sludge aeration system in schematic form. It should be understood that for normal aeration in an activated sludge system approximately 15,000 cubic feet per pound is utilized, which means 100 pounds of air per pound of BOD or 20 pounds of oxygen per pound BOD, and in effect represents 5% efficiency. With the system described hereinbelow 75 to 150 cubic feet of air per pound is utilized which means S to 10 pounds of air per pound of BOD or 1 to 2 pounds of oxygen per pound of BOD or a 50%
to 100% efficiency range.
Referring to Fig. 35, the numeral 600 represents an activated sludge tank. Suction is taken from one or more places on the tank near to the bottom outside edge by one or more appropriate low head centrifugal pumps indicated by nu-meral 602 through suction iines 604. Pump 602 then discharged through lines 606 back into a substantially central and upward-ly directed outlet or discharge line 608 near the bottom center of tank 600. This creates a vorter flow in the eliptical paths shown by arrows 601 and insures that all liquid in the tank ~ ~ :
will tend to flow or move around the path. There should not be any stagnant areas.
In order to inject air then into this configuration, appropriate air compressors 610 are connected by line 612 to direct air into the discharge line 606 through approximately the same type of injection mixing system shown in the injec-tion elbow 514 of Fig. 34. This achieves ~x; Im diffusion of the air within the effLuent from the pumps 602, suppresses radial concentration gradients, and gives an extremely effici-ent way of aerating the activated sludge. Normally the pump 602 will be a low head, high volume pump which is convention-ally available.

'

Claims (12)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An apparatus for the treatment of a fluid by a treating fluid which is characterized by a flow pipe for a fluid having a Reynolds Number of at least 3,000, said flow pipe having a flat plate orifice located therein, a vena contracta portion located in said fluid in said flow pipe at a distance of from 0.25 to 0.5 pipe diameters downstream from said flat plate orifice, the internal diameter of said flat plate orifice ranging from about 0.7 to about 0.9 of the internal diameter of said pipe, and a thin injection nozzle means for introducing a treating fluid into said flow pipe, said injection nozzle extending through said flat plate orifice, said nozzle having a thin tip, said treating fluid flowing through said nozzle tip, said nozzle tip located in said vena contracta portion so that said treating fluid is dispersed into said fluid, said nozzle tip being located at about 0.25 to about 0.5 pipe diameters downstream from said flat plate orifice so that said fluid is thoroughly treated with said treating fluid.

2. An apparatus according to Claim 1, wherein said fluid is a gas and said treating fluid is a gas.

3. An apparatus according to Claim 1, including a downstream flat plate orifice located at least 40 conduit diameters downstream, said downstream flat plate orifice having a diameter of from 0.7 to 0.9 conduit diameters.

4. An apparatus according to Claim 1, including an abrupt change in diameter of said conduit diameter, said abrupt change located downstream from said flat plate orifice.

5. An apparatus according to Claim 2, including an abrupt change in the diameter of said conduit diameter, said abrupt change located downstream from said flat plate orifice.

6. An apparatus according to Claim 1, including another flat plate orifice located at least 25 conduit diameters downstream, said downstream flat plate orifice having a diameter of from 0.7 to 0.9 conduit diameters.

7. An apparatus according to Claim 2, including another flat plate orifice located at least 25 conduit diameters downstream, said downstream flat plate orifice having a diameter of from 0.7 to 0.9 conduit diameters.

8. An apparatus according to Claim 6, wherein said nozzle tip is located from about 0.36 to about 0.39 conduit diameters downstream from said flat plate orifice.

9. An apparatus according to Claim 7, wherein said nozzle tip is located from about 0.36 to about 0.39 conduit diameters downstream from said flat plate orifice.

10. An apparatus according to Claim 6, wherein said nozzle tip has an outwardly tapered portion, said taper being less than 7 degrees.

11. An apparatus according to Claim 7, wherein said nozzle tip has an outwardly tapered portion, said taper being less than 7 degrees.

12. An apparatus according to Claim 8, wherein said nozzle tip has an outwardly tapered portion, said taper being less than 7 degrees.