DE3138246A1 - METHOD AND DEVICE FOR TREATING WASTEWATER - Google Patents

Description

Method and device for the treatment of

Sewage . . . .

The invention relates to a method for treating waste water and the device for carrying out this method. In particular, the invention relates to an improved method for treating waste water, in which the separation ,, the concentration and treatment of poorly settable and colloidal solids by fine sand filtration is increased, thereby increasing the energy generation potential of the treatment process and the subsequent The need for biological treatments is reduced or eliminated. Through the invention capital expenditures and energy costs are reduced.

Solids contained in wastewater can either be suspended or dissolved. They can be filterable or be infiltratable, volatile or inert and can be biodegradable be or not. These provide solids as well as fats and oils that are typically found in wastewater are generally the major environmental pollutants, and it is these harmful materials must either be removed or treated in the wastewater treatment process.

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The suspended solids range in size from 10 µm (microns) to 100 µm (microns) and larger. In general solids of 10 µm (microns) and larger are settable and can be removed by gravity separation. Fixed-

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Substances of 10 µm to 10 Pa (microns) normally settle do not decrease and generally require coagulation or flocculation for removal. Solids of 10 pm (Microns) and smaller are generally considered to be dissolved solids.

Most biological wastewater treatment systems and processes are designed to facilitate the separation of the large insoluble particles and the biological treatment of the particles, that do not settle affect. Many of these systems operate erratically because of their general inflexibility the known methods, i.e. primary classification and / or sieving.

Primary procedures can respond to a very wide range of fluid and / or subject to organic pollution, which leads to an effluent of varying quality. The biological Systems that are subsequently used must operate within this variation in load, thereby increasing effectiveness of the biological system can be reduced to a minimum.

The suspended and colloidal solids that were not separated by sieving or clarification must be above can also be treated by one or more biological systems to match levels of secondary treatment. The energy, capital, and maintenance costs of such systems are significant.

Two such commonly used biological systems are the suspended growth modifications of the process activated sludge and the system of modifications of the fixed growth of the trickle filter method. These systems can vary from very simple to very complicated procedures depending on the size of the facility and the one used Equipment. The requirements for downstream nitrification

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They also complicate the process and add capital and energy costs to additional equipment.

Numerous "attempts have been made to the treatment methods to modify in order to reduce the energy costs of biological systems. This has generally been attempted by Modifying the process and changing the design of various mechanical components to improve effectiveness to improve the solids separation of the sewage treatment plant. An effective technique for solids separation used has been Addition of a chemical coagulant to the incoming water, which flows into the gravity settler or the sewage treatment plant enters. This technique increases the amount of separated solids materially and the organic ones The burden on the biological system or the subsequent treatment systems is reduced.

This reduction in stress leads to a reduction in the energy required for the biological processes is. Physico-chemical processes recommended for the treatment of wastewater generally draw the suffix a coagulant and flocculation of the suspended particles into consideration. This will be common to either carried out in a zone within the sewage treatment plant or in front of the sewage treatment plant in order to settle the suspended To improve solids. The treated wastewater can then be treated in a number of ways, such as by absorbing it on activated carbon or even re-filtering, followed by carbon absorption.

However, the addition of a chemical flocculant works and / or a coagulant at an additional chemical cost and in many cases leads to serious problems that are essential greater than the benefits obtained by reducing the suspended solids that are in the biological System are discharged.

The precipitation of the coagulant leads to a chemical Sludge, and it can be very difficult and very costly to treat and drain. aside from that the chemical sludge generally adversely affects the generation of sludge gas.

/ Biologically treated in an activated sludge system organic material generally creates new and additional cellular material. This highly structured cell material eventually leads to the possibility of secondary pollution and must therefore be careful separated and removed in such a way that it does not affect the environment. Therefore, in most biological system of the activated sludge or the trickle humus, both of which are mainly made up consist of new cell material from which wastewater is separated. This is generally achieved through second or secondary Sewage treatment plants. The settled sludge can be returned to a digester for further biodegradation will. The digested sludge is then drawn off and dewatered in various ways. That Digestion, dehydration, and removal of the new cellular materials are difficult and costly processes.

Granular media filters are currently used to remove suspended particulate matter from wastewater, following other stages of treatment. Such a filter effectively used for such purposes is disclosed in US Pat U.S. Reissue PS 28,458, dated July 1, 1975. Improvements are described in U.S. Patent 3,817,378 issued June 18, 1974 and U.S. Patent 3,840,117 issued October 8, 1974.

An effective method and device for cleaning fats and oils from the media of granular media filters is described in U.S. Patent 4,032,443 issued June 28, 1977.

An apparatus and method for separation and concentration solids from filter backwash fluids is described in U.S. Patent No. 3,792,773.

An object of the invention is to make many of the disadvantages more common Overcoming wastewater treatment systems by removing and collecting organic solids from wastewater, the household wastewater contains, without the application of coagulant chemicals, a major improvement is the added energy potential the increased amount of chemical-free primary sludge. Another major benefit is a corresponding reduction the creation of new cellular plant material.

The invention relates to a method for treating waste water to remove suspended and / or colloidal materials, including possible fats and oils, from beforehand untreated wastewater containing household wastewater, which has the following stages:

a) Feeding the wastewater containing household wastewater to a clarifier or sieve device to remove some of the materials and to clarify the waste water, without essential chemical additive;

b) Channeling the treated wastewater without the addition of significant chemicals through a granular media filter in a filter canister to an underflow cavity, for formation a filtrate containing less than 40% of the suspended solids present in the untreated Wastewater are included;

intermittently directing air upward through the granular medium to reduce drag through the medium and to inhibit anaerobic biological activity therein without compromising the integrity or the Destroy the integrity of the filter; and

d) this filter intermittently with part of the filtrate and backwashing a surfactant and / or oxidizing agent to remove accumulated harmful materials to remove.

So wastewater that contains household wastewater is turned into a Device, such as a net, a sieve and / or a primary sewage treatment plant passed through a granular medium filter without previous biological chemical or physico-chemical treatment. Alternatively, the device can be used for removal the solids are omitted entirely; Waste water is fed directly into the inlet of the filter and is not settable and colloidal solids are captured by the filter media and off the surface of the filter media adsorbed.

The effectiveness of removing these non-settling solids is a function of the extent of application or the physical characteristics of the medium, typically sand. Generally at least 60% of the suspended material will be removed by a single filter. Solids can collect or accumulate in the filter medium until the resistance through the filter medium leads to the The water level above the medium has reached a predetermined level, at which point the filter is backwashed and harmful materials that have previously been entrapped and adsorbed are rinsed from the medium and washed will.

The invention also provides an improvement in interception and the storage of the colloidal and suspended particles by periodically reducing the resistance of the filter medium, body and surface achieved by conduction of air in an upward direction through the medium, in an intermittent manner, to improve the porosity and the anaerobic To stop decomposition. This air is created by lifting the

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Filtrate in the underflow cavity and displacing the air, directed upwards. The upward movement of the air is enough designed to move harmful materials into the interior of the filter bed, where such materials are temporarily stored, without disturbing the wholeness or integrity of the filter medium.

According to another feature of the invention, a method provided for backwashing, in which vertical liquid or hydraulic jets are applied intermittently with air be a high speed movement and a medium movement with variable under the resuspension lying extent (subfluidized) to improve the effectiveness. the backwash system and under application a minimal amount of backwash water.

According to a further feature of the invention, the backwashed Water led to a receptacle in which the previously non-settling particles that are now in the backwash water, agglomerate and settle. Fats and oils are also allowed to be skimmed off agglomerate. The settled solids can generally concentrate without the addition of chemicals. According to a further feature of the invention, the backwashed Solids to a digester for the anaerobic stabilization of the organic material and for the biological Pumped generation of methane and carbon dioxide fuel gas.

According to a further feature of the invention, clarified backwash water can be returned to the inlet of the filter for renewed Filtration can be performed and under certain conditions can lead to a Aufnähmestrom or a watercourse, such as a lake, a river, a sea, etc.

The environmental pollution characteristics of the filtrate will be

significantly reduced by removing the colloidal and non-settling solids in the treated wastewater available.

According to a further feature of the invention, oxygen is added to the bulk liquid by impingement, diffuser and added by pulsing through the filter medium. to the normal oxygen deficiency of the treated wastewater au Minimize and counteract anaerobic conditions in the medium and the liquid filter body.

According to a further feature of the invention there is provided an improved medium regeneration cycle which Fat, oil and biological materials that adhere to the surface of the medium by emulsifying and hydraulically and pneumatically induced movement of the media bed. In addition, an oxidizing agent such as hypochlorite is used used with or without a surfactant to regenerate medium surfaces. Preferably however, a non-halogen oxidizing agent such as hydrogen peroxide, oxygen-containing gas or gas is used Liquid, or ozone, either with or without a detergent or detergent or surfactant used, whereby the formation of chlorinated hydrocarbons is avoided.

Another key feature of the invention is that it can be carried out in stages the filtration process to determine the amount of unsettled or colloidal solids that are released from the wastewater removed to enlarge. Typically, in a two-stage filter system, the secondary filtrate will contain less than 25% of the suspended solids in the untreated water and has the associated low BOD on. Such filtrates can generally be used directly can be emptied into a watercourse without prior biological treatment.

Another feature of the invention is application very small amounts of coagulant between the stages of the filtering process, in addition to the very small particles further reduce, which are neither captured nor adsorbed by the medium surface. The chemical used for Coagulation is rapidly mixed with the primary filtrate and sent to the second filter without a flocculation step. Such a procedure typically results in a secondary filtrate that suspended less than 20 mg / l Has solids and may contain less BOD than is normally attributed to secondary processes. The first filter stage removes most of the solids, and only very small amounts of coagulant are required for the second stage. This is how the effect is such chemicals on the subsequent sludge treatment are negligible.

Another object of the invention is the use of a filter for treating excessive flows, which can adversely affect an existing or fixed biological system by diverting excess Currents around the biological system through a fine medium filter and removing sufficient amounts of it suspended solids from this diverted wastewater, as well as from the biologically treated wastewater. this makes possible filtering the treated and untreated wastewater to meet drainage regulations. According to the invention the effectiveness of the biological process is retained. The biological process is against fluid overload protected, and the overall performance is ensured.

Another feature of the invention is the combination of two-stage filtration within a single vessel under varying level conditions depending on the flow rates, which is designed in such a way that a part is extremely rigid

ker flows can be absorbed by coarser filter media.

The two-stage filter allows the use of more than one size of sand and different application rates or speeds for a given filter load.

Another feature of the invention is the washing or rinsing of the vertical walls of the filter container on one automatically selected base during a back wash. A cleaning agent such as a laundry detergent, and an oxidizing agent or, alternatively, a surfactant and an oxidizing agent can be added to the backwash water to further clean the walls. The addition of detergent can be controlled manually or on an automatic choice basis. Preferred is a non-halogenated oxidizing agent.

Another feature of the invention resides in the addition of an oxidizing or sterilizing liquid to the backwashing liquid at the end of the backwash cycle to control the growth of biological materials. This sterilizing or oxidizing liquid also leads to oxidation, emulsification or removal of the previously adhered organic substances on the medium surfaces, resül * due to the filtration of the treated wastewater through the medium of fine sand. The medium surfaces are used effectively to absorb some of the organic components that make up soluble BOD.

Another feature of the invention resides in the ability to reduce deleterious effects of the colloidal and suspended particles, which clog the pores of activated carbon and cover the carbon surfaces with organic substances that cause the Limit the effective use of activated charcoal to a minimum.

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Another feature of the invention is an improved one Under-drainage system or under-drainage system, which effectively feeds the oxidizing or sterilizing liquid into the Filter medium distributed without prior mixing with the backwash liquid and the detergent or surface-active Middle.

The figures are briefly explained below.

FIG. 1 shows a schematic flow diagram of a conventional sewage system, the main elements of which are a primary clarification device, a biological treatment system, a final clarification device and a sludge digester.

Figure 2 is a schematic flow sheet of the preferred embodiment of the invention illustrating the various alternative treatment systems that may be employed.

Figure 3 is a flow sheet of the invention combined with biological treatment.

Figure 4 is a flow sheet of the invention combined with a biological treatment system followed by a second filter.

Figure 5 is a diagram of a physico-chemical treatment process that is used between two filters »

FIG. 6 is a diagram showing the application of the invention to a waste treatment system which is subject to large changes in the incoming flows and illustrates the possibility of treatment by means of bypass flows.

FIG. 7 is a cross section of the device according to the invention, which is used in the treatment of bypass currents

is turned.

Figure 8 is a cross section through the inventive device, showing the Wandungswäsche and the pulsating bed system.

Figure 9 is a cross-sectional view of the sub-drain support system described in accordance with the present invention.

Figure 10 is a detail section of an outlet nozzle of the sub-drain support system described in accordance with the present invention.

Figure 11 is a cross-sectional view of an alternative to the nozzle detail of the sub-drain support system described in accordance with the present invention.

A preferred embodiment of the invention will now be described. The reduction in total biochemical oxygen demand (BOD) of suspended solids and soluble BOD of household clarified wastewater by parallel granular media filters are illustrated in Table I, wherein the granular media used in the filters are made of quartz with an effective size of 0.35 mm and 0.45 mm, respectively, at a sand depth of 25.4 cm (10 inches) and application rates of 80 liters per minute per m (2 gpm / ft ² ).

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Table I.

filter i 46 filter filter 131.5 number 1 No. 2 . A stream . Outflow Outflow Sand size, mm 35.3 0.35 0.45 Suspended solids, mg / l 81.3 20.8 25.7 Removal effectiveness ^,! (74.6) (68.6) Turbidity FTU 23 24 Total BOD, -, mg / 1 49.0 53.9 Removal effectiveness, * (62.7) (59.0) Soluble BOD ₅ mg / 1 23.3 24.9 Removal efficiency% (34.0) (29.3)

Average filter run length, h backwash to filtrate ratio 1/1

3.0

0.168

6.0

0.088

A major factor that is generally overlooked in the construction and development of wastewater treatment systems is
lies in the fact that the main part of the organic polluting pollution in waste water, represented either as theoretical oxygen demand (TSB), chemical oxygen demand
(COD) or biochemical oxygen demand (BOD) in the
non-settable suspended and colloidal solids
is included. Such solids are found in household wastewater. For example, sewage solids have the
separated by their size, which are listed in Table II
Organic pollution shown on «Basic is 66%
the organic pollutant load in the suspended solids with the particle size of 8 µm (microns) and less as measured by the COD. Generally goes

it is believed that suspended solids of 8 µm (microns) and less are not self-settling.

The importance of the polluting load of clarified or settled sewage can be further illustrated by a size and weight analysis of a clarified Wastewater sample. The sample of Table II was taken from the sewage treatment plant Taken in Lorain Ohio and is typical of treated wastewater that includes domestic wastewater Wastewater samples were filtered successively through membrane filters with increasingly smaller pores. The ones in everyone The amount of solids retained by the filter was then determined, as was the chemical oxygen demand (COD) was determined for the retained solids.

Tabel'le.XI

Primary effluent from Lorain Ohio settled wastewater TSS 84.5 mg / l; COD 182 mg / 1

Filter pore TSS, retained COD, which is the fiI size, pn passed through the filter, mg / 1 ter, mg / 1

8.00 38.4 121.0

3.00 14.7 80.9

1.20 10.7 62.7

0.80 11.5 62.7

0.45 7.6 65.9

0.22 1.6 48.9

The reduction in soluble BOD is a further feature of the invention. The reduction in soluble BOD by

Fine sand filtration is of great importance and becomes even more important with lower liquid application quantities. For example, research has shown that the reduction in soluble BOD is in the range of as high such as a 34% reduction to as low as 5.6%. Of the Soluble BOD is more of a definition than a proper description. Colloidal particles passing through a filter of 0.45 ρ (microns) can be run as a part the soluble fraction, which is measured as soluble BOD.

A substantial amount of the colloidal material that passes through

running a 0.45 µm (micron) membrane filter remains by itself

adhere and will stick to the grain surface in a granular medium filter adsorbed. Some of the organic materials in the solution also rapidly become biologically in Biomass converted when the wash water passes through a granular bed. The removed set represents a function the extent of use or the speed and the size and depth of the sand.

Table III shows a specific series of tests and illustrates the effectiveness of the removal of the soluble BOD by the invention. Thus, through a single or multi-stage filtration, not only the measurable, Solids content that cannot be deposited is removed, but the soluble fraction of the organic load is also essential decreased.

Table III

Soluble BOD reduction ₅ (%)

Flow rate or _n ,,. _{mrn n ΑΚ mm}

Speed 0.35mm 0.45mm

2
40 l / min / m 34 (2GPM / FT ² ) 2
200 l / min / m 18.3 (5 GPM / FT ² ) 320 l / min / m ² 7.2 (8 GPM / FT ² )

29.5

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5.6

In the drawings, preferred embodiments of the Invention shown without representing a limitation.

A conventional biological wastewater treatment process is shown in FIG outlined. The raw sewage inlet line 10 leads to the crushing or screening device 20 and through a line 11 to the first settling device or first clarifier 100. The clarified liquid is conveyed through line 110 to the biological process where the waste is biologically treated, with the formation of new cellular material, and is passed through the pipe led to the last settling tank 500. A majority of the sludge solids settle in the clarifier 500 and withdrawn through line 520. Part of the mud is recycled to the biological process via line 521. The excess or waste sludge is then with mixed with the sludge that was withdrawn from the first sewage treatment plant 100 through line 120 and the mixture of the Sewage sludge and the primary sludge is

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device 121 to the digester 800 / where the sludge is further treated and some of the organic materials are converted into methane and carbon dioxide. The excess Wastewater sludge from the sewage treatment plant 500 can be fed directly into the Digestor 800, avoiding the mixing process on line 121, depending on the will of the operating personnel.

FIG. 2 shows a schematic block diagram of the invention in which a filter system 200 is applied to a primary settling tank or a sewage treatment plant 100 follows. The sewage treatment system includes a sewage inlet line 10 in which sewage for comminution and / or coarse screening device 20 and then through line 11 to a primary Sewage treatment plant 100 is performed. The clarified effluent exits primary treatment plant 100 through line 110 to the inlet of the filter 200.

As shown in Figure 2, the filtrate in line 210 is passed to one or more subsequent treatment elements, such as biological treatment, which can be either the suspended growth system or the attached growth system. Alternatively, _au f the filtration followed by a second filtration stage and then a treatment with activated carbon or a biological treatment for the removal of organic material and / or nitrogen, or can be discharged into a receiving stream or any other device for treatment or reuse. The need for the optional second stage filtration is a function of the sewage quality and particle size distribution, as well as government sewage regulations. In many cases the feed to the biological system is reduced so that an adequate biological treatment is achieved, for example in a trickle filter, without any recirculation.

• «Another embodiment of the invention consists in one Wastewater treatment processes for the removal of suspended and colloidal materials, including fats and oils, protein-containing compounds and ammonia nitrogen from previously untreated wastewater, household wastewater contains where

a) the wastewater, which contains household wastewater, to a Clarifying or sieving device is carried out to remove some of the materials and to clarify the wastewater, without the addition of chemicals;

b) clarified wastewater without the addition of chemicals through a first granular filter within a first filter container is passed to a first sub-drainage cavity to form a primary filtrate;

c) the primary filtrate through a fixed media filter, such as a trickle filter, with nitrifying microorganisms, which grow on the fixed media, is passed to convert the nitrogen in the primary filtrate to nitrate and nitrite oxidize;

d) the nitrified primary filtrate is passed through a second granular medium filter with a second filter vessel to a second sub-drainage cavity to form a secondary filtrate containing less than 20 mg / 1 suspended solids and 20 mg / 1 BOD ₅ ;

e) air is intermittently passed upward through each granular medium to reduce the resistance to flow through the media to decrease and inhibit anaerobic biological activity therein;

f) intermittently the first filter with a portion of the primary filtrate and a surfactant and / or

backwashing oxidizing agent to remove accumulated harmful material;

g) intermittently the second filter with part of the Secondary filtrate and a surfactant and / or oxidizer is backwashed to remove accumulated harmful material.

Such treatment tends to result in a secondary filtrate containing less than 20 mg / 1 suspended solids and 20 mg / 1 BOD ₁ . even if the pinned media

2 filters at a rate equal to or greater than 13.6 l / min / m (0.34

GPM / FT) is operated without recirculation. The secondary

filtrate contains less than 1.5 mg / 1 NH.-N, if the wastewater temperature Exceeds 20 ° C.

The backwash from filter 200 is emptied through line 220 to clarifier 300, where the backwashed Solids can settle and the supernatant liquid of the sewage treatment plant is to the inlet of the filter 200 through the Line 310 and filter inlet line 110 returned. The quality of the supernatant liquid can be increased by adding coagulating chemicals. The deposed Sludge from clarifier 300 is withdrawn through line 320 and to sludge discharge line 122 guided, which transports the sludge from the primary clarifier 100 through the line 120.

The filtrate quality depends on the rate of wastewater application, the wastewater contaminant concentrations, and the bed depth the mean grain size used in filter 200. The filtrate quality can be further followed by several optional treatments are increased depending on the final water quality required.

The energy required for the subsequent treatment of the

treated wastewater is considerably reduced by the reduction the organic pollution of the treated wastewater, which is achieved by the filter 200.

Additionally, the sludge created by the concentrated Contaminants in the backwash water obtained from the filter 200 are added to the sludge that is in the primary settling tank or the sewage treatment plant or treatment facility 100 is removed. The total amount of primary sludge is the sum of the primary sludge, which is developed both in the gravity sewage treatment plant 100 and in the filter 200. The fact that neither Adding a coagulant to the inlet of the primary settling tank or the filter ensures that the Total sludge that is withdrawn contains a minimum of treatment chemicals.

The anaerobic biological production of fuel gas methane from water sludge is known to proceed faster and more effectively away when the ratio of primary sludge to secondary biological sludge is high! The invention leads to considerably increased amounts of primary solids and considerably reduced amounts of secondary solids.

For example, typical household sewage includes 160 mg / 1 suspended solids, half of which can be removed by a simple primary treatment without chemicals will.

The treated wastewater typically shows the following analysis:

suspended solids 80 mg / 1 BOD ₅ 130 mg / 1

In a standard treatment, the clarified wastewater is subjected to a treatment with activated sludge to avoid secondary

Meet government standards. Approximately 70 mg / 1 biological sludge solids are produced. The biological solids are almost half of the total solids load that is normally digested anaerobically.

According to the invention, the clarified wastewater is granular Medium filtered to meet secondary standards, replacing the biological level, the high j Requires equipment and operating costs.

In addition, no solids from the biological treatment are fed to the anaerobic digester; therefore be the gas production and the reduction of the solids as well as the subsequent solids dewatering increased in each case.

The biological treatment goes through a filtration granular medium precedes the greatly reduced Amount of new cell material results in a significantly improved digestor efficiency.

In FIG. 2, the line 151, which follows the second filtration stage, can pass the filtrate to a contact device lead with activated charcoal. The filtrate can alternatively be treated in a biological system, as further shown in Figure 3, or emptied into a stream or reused. Alternatively, the second filtration stage can be omitted and a one-stage filtrate can be routed to the alternative processes mentioned.

A major advantage of the invention is the reduction in organic pollution for all subsequent ones Treatment systems through filter 200, thereby reducing energy and capital requirements.

In FIG. 3, the same type of secondary biological process is illustrated as in FIG. 1,

the process in the secondary treatment plant now being modified by the use of a filter can be installed in line 110 for the clarified effluent is. The filtrate contained in outlet 210 requires significantly reduced biological treatment. The biologically treated wastewater can be fed to a final settling device or a sewage treatment plant 500 or a subsequent filter 700, such as illustrated in Figure 4, and then to the chlorine contact tank 600.

According to the invention, too, the primary sludge is made from the primary Settlement tank 100 withdrawn through line 120. The generally non-settable and colloidal solids in The clarified wastewater is then collected by the filter 200, with the filtrate from the filter 200 then passing through the line 210 is led to the biological process 400. The backwash water in line 220 becomes the inlet the backwash separator 300 out, where the backwashed solids can settle and emptied and will be mixed with the solids of the primary settling tank 100, thereby reducing the total primary solids that are made up removed during the procedure.

The organic feed to the biological process is enhanced by the greater removal of organic solids considerably reduced. Again depending on the application and the medium size, the remaining organic Feeding to the biological process can be reduced to a point where the new cell growth effectively intercepted by a second filter of generally the same type as that used in filter 200, and a final settling device is not required. The filter 700 then traps the mixture of solids and new cells and passes these solids to the inlet of biological process 400 through conduit

721, as shown in Figure 4, back excess sewage solids are then drained to backwash separator 300 through line 722.

According to the invention the potential for the growth of new cell material through the reduction in suspended and non-settable material through the granular medium filtration limited. The growth of new cells is proportional to the organic load in the Waste water entering the biological process through line 210.

If, for example, one assumes an extent for the growth of new cells of 0.4 kg (or Ib) new cells per kg (or Ib) removed BOD, the filtrate residue, which contains 50 mg / 1 BOD ₅ , would only be 20 mg / 1 create new cells. Wastewater with a suspended solids content of less than 30 mg / 1 solids and corresponding values for the biochemical oxygen demand can be classified as secondary runoff. If the suspended solids exceed the allowable flow requirements of the particular watercourse, a second filter can be added and the 20 mg / l new cells can be easily separated by the filter and the filtrate through line 710 then conforms to low solids flow regulations. If the flow regulations are such that the solids to be removed do not go beyond this regulation, no further treatment is required.

In FIG. 5, a separated primary effluent becomes the first filter stage 200 out, and the filtrate is passed through line 210 to the mixing chamber 30, where very little Concentrations of coagulant are pumped from the vessel 40 into the mixing chamber 30 through the line 50. The coagulant is mixed in the mixing chamber 30 with the filtrate of the first stage from the filter 200 and

the coagulant-filtrate mixture becomes the filter 700 emptied through line 211 without a flocculation step. The coagulant-filtrate mixture is then through the Filter 700 is filtered and the second stage filtrate is drained through line 710. The backwash liquid from the first filter stage 200 is emptied to the backwash receptacle 300 through line 220, and the backwash from filter 700 also goes to the same backwash solids separator through the Line 720 led. The settled sludge in the vessel 300 is emptied through line 320 and with the sludge which is removed from the primary vessel 100 through line 120, and the combined volume of sludge becomes the digester 800 through the line 123 passed.

The effluent from the line 710 can then optionally in a number of ways depending on the requirements for the final Application or to be treated for the emptying of the treated wastewater. Water that is filtered again is, as shown in FIG End use and requirements or regulations. This type of system reduces the biological cell growth material, which is normally present in biological treatment plants, goes strong or completely switches it off and a high quality effluent is formed at the same time. The limit, of course, lies with the soluble ones Components that can now not be removed by filtration. The effluent effluent from which the suspended solids and colloidal solids removed by filtration can easily come into contact with activated carbon for adsorption be guided by remaining organic components. This type of pretreatment can be effective in large space and space Saving energy requirements and leading to an effluent with controlled quality. This is particularly true many areas of water reuse too.

The filtration process leads to a reduction in the energy requirement that is normally associated with conventional wastewater treatment, which leads to a similar performance.

In Figure 6, the first filtration can be successfully applied to wastewater treatment systems that are extremely subject to high flow changes, such as during storms, where known biological processes are controlled by a hydraulic or fluid overload are threatened. In FIG. 6, the inflow line 10 represents the inflow line for wastewater, including various volumes of storm water passing through a crushing or screening device 20 arrive and then through an alternative flow diversion chamber and an excess flow weir 60 are passed into the primary settling chamber 100. The clarified effluent in the line 110 becomes the hydraulic control chamber 80 led where an excess flow of the first stage is routed around biological process 400 and final sewage treatment plant 500 into line 510 which is the inflow line in the filter 200. The backwash water is from the filter 200 to line 220 to the sedimentation vessel 300 led. The supernatant liquid from settler 300 is returned to line 510 through line 310. The settled sludge is through the pipe 320 and mixed with the settled sludge from the sewage treatment plant 100 through the line 120 and for further treatment through line 124 to a digester or "other sludge treatment process."

According to the invention, the excess currents around the biological Procedure diverted in order to protect the entire biological process from a hydraulic shock or liquid shock and, in addition, the biochemical oxygen demand of bypass current by passing it through line 90 under the action of filter 200

to reduce the suspended solids.

In Figure 6, excess flows can also be diverted around the primary sewage treatment plant 100 if there are signs that the maximum fluid conditions of the sewage treatment plant 100 would be exceeded. Therefore, a bypass chamber 60 can be installed at the beginning of the primary sewage treatment plant 100 and the flows in excess of the intended values can be directed through line 70 into bypass line 91 to line 510 in filter 200 for further improvement by removing suspended solids by filtration.

Another feature of the invention is capability the filter device to meet different filtration requirements when the inflowing volumes through the The effects of storm water currents and dry weather currents can be changed. During dry weather when the sewage flows are low, the residence times of the solids in the sewer lines are relatively long, what leads to significant dissolution of the contaminating material. The wastewater BOD - is high.

On the other hand, higher water levels flush during periods of wet weather the sewers quickly. The wastewater is not only diluted by the extra water, but is "fresher", i.e. a lower resolution has occurred.

It is true that strong currents prevent the normal biological operation from operating Treatment systems, however, are the contaminating materials in such high-flowing sewage More accessible to removal by granular medium filtration than is contamination in weakly flowing wastewater are. Hence, it remains with the diversion of excess flows of sewage around biological treatment systems around to a granular medium filter a high biological

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Treatment level obtained during the excess currents a highly effective filtration treatment becomes its own. A useful effluent is obtained at a point in time when the effluent quality is usually deteriorated.

According to another embodiment, this results in one run Granular medium filter of Figure 7 an effective and sufficient treatment of wastewater with very widely varying Flow rates. In FIG. 7, the treated and diverted inflowing flows to the filter vessel 200 - through the line 510, as illustrated above in Figure 6, guided. In FIG. 7, a flow indicator 530, which is located in line 510, indicates the amount of Flow to the filter on. Valve 512 remains open within the existing limits and in the lower level range, and valve 514 remains closed. The current in dry weather with low water level from the pipe 510 enters filter 200 when the upper liquid level is low above filter media 250. With increasing Flow signals flow meter 530 to close valves 512 and open valve 514, and the water level it becomes possible to enter the filter 200 at a higher point.

Simultaneously, the flow indicator 530 changes the operating level from the current operating level indicated at 240 becomes, to level 242 and possibly up to 244, whereby the capacity of the filter is increased. If the If flow continues to increase, the signal from flow indicator 530 then limits flow through the flow distribution chamber 516 to filter 200 and causes a corresponding Flow through conduit 518 is brought into filter vessel 200A, which is entirely within the confines of of the filter vessel 200 is located. The filtrates from the filter 200 and from filter 200A passing through lines 223

O I J Ö / 4 U

and 223Α are then run in a single line mixed with one another, to the effluent from the plant. The levels of work within the filter 200 are in turn changed proportionally to the flow requirement, as determined by the Flow indicator 530 is controlled.

In FIG. 7, the backwash through the filter 260 is above the filter sand 250, and the water level is before the backwash 240 lowered to the level of the backwash by the weir 262. According to the prior art, this water volume is added to the volume of backwash water above the filter through weir 262, thereby increasing the amount of backwash water to be treated is increased.

If the operating water level is due to the flow indicator increased to 242 or 244 or intermediate levels, of course, the volume of waste water is increased.

A feature of the invention is to locate the filter cell 200A entirely within the confines of the filter 200, whereby the volume of water above the filter bed 150 (or 250) is reduced without the effectiveness of the filter system to reduce. The volume of the wastewater is thus reduced.

Another feature of the invention is to divert the volume of water via weir 262 into a separate emptying chamber 270 to drain before the backwash pump 222 is put into operation, increasing the volume of the to be treated Backwash water is greatly reduced. The order of the backwash process is indicated by a backwash demand signal from the level sensor 352, 354 or 356 according to the appropriate water level 240, 242 or 244, as controlled by the signal from the flow indicator 530, initiated. At the signal, the valve 277 opens and allows the water to pass through the pipe via the weir 262

266 to the sewage emptying chamber 270, wherein the total volume of the liquid above the weir 262 is now is included. After the liquid is over the weir 262 as brought about by a signal from a timer device is drained, the valve 277 is closed and the valve 278 is opened, the backwash pump 222 is then energized, valve 226 is opened, valve 225 is closed, and the backwash liquid is then into the sub-drainage cavity (or sub-drainage cavity) 208 and through the sand bed 250 directed towards overflow weir 262. The backwash liquid is then directed to the backwash receptacle 290 and can be further treated as described in commonly assigned US Pat. No. 3,792,773. The liquid one Volume that is now in the container 270 is pumped into the filter 200 by the pump 272 after the pump 222 was turned off, the valve 226 was closed and the valve 225 was opened and the filtrate from the Filter 200 is again led to the filtrate receiving container "Klärbrunnen" 280.

The volume of liquid above weir 262 contains less solids than the backwash liquid. By mixing this volume increases the total liquid volume, and the cost of treating the volume of liquid by diluting the backwash mixture is increased. This dilution reduces the possibility of mixing to achieve an auto-flocculation point without the addition of Chemicals. Auto-flocculation or self-flocculation or agglomeration takes place more easily with increased solids concentration.

The upper water drain of the filter chamber, which is part of the filter system in FIG. 7 with other features of the invention shown can be used independently. This feature leads to the reduced volume of the headwater

to an improvement in operating costs and performance in any filtration system where volumes of water are stored above the level of the backwash weir.

By modifying the pipeline, this filter can · also to treat wastewater in two consecutive Stages are used. In this case the wastewater is first passed through the upper filter bed 250A and then through the Filter bed 250 passed. The granular medium in the first bed 250A will be relatively coarse while the bed 250 is out finer granules will exist.

Another embodiment of the filter is shown in FIG 200 illustrates. A circumferential wash ring 226 is attached to the top wall of the filter 200, with nozzles 228, which are attached so that they 'clean the walls of the filter 200. The supply line 224 for the wash ring . communicates with backwash pump 222, and chemical feed pump 262 by line 266. A The feature of this invention is the use of a special cleaning solution for backwashing the walls of the filter predetermined time periods. By filtering the primary wastewater, heavily contaminated biological wastewater is in introduced the filter cell. The biological waste covers the walls where biomaterials can grow. at in the absence of oxygen, unpleasant growth and smells occur. Effective cleaning and disinfection the walls is necessary for the overall operation of the filter systems to improve.

Another feature of the invention resides in the improved backwashing system for removing the particles that are tough on the Sticking medium grains and the introduction of a cleaning and disinfecting solution into the medium at preselected times, to stop biological growth.

In FIG. 8, reference is made to the backwashing technique a high pressure air system is alternately provided by air pressure pump 280 that supplies air through line 282 static mixer 284 where air and backwash water are mixed and this mixture to the sub-drainage cavity 208 is directed.

The air that is intermittently fed into the static mixer 284 causes additional agitation of the medium 250 by the pulsating vertically ascending rays 292 in the sub-drainage system. This is how the backwash cleans it Medium more carefully than was previously possible and puts on the need for frequent chemical cleaning a minimum. However, the same system is designed so that the chemical enters the sub-drainage system from the chemical holding tank 260 can be fed to adequately disinfect the filter media, thereby the build-up of biological materials is stopped either in the medium or on the filter surface.

The main problem associated with the filtering process of wastewater is the adsorption and accumulation of colloidal ones Fats and / or oil films on the surface of the medium grains. This particular problem is exacerbated by the high percentage on colloidal fat or oil present in primary currents or combined storm and primary currents are. Contact with and backwashing with a washing solution or detergent solution or an oxidizing agent and a surfactant effectively removes colloidal fat and oil from the surface of the grains of the medium.

Thus, another feature of the invention is improvement the sub-drainage system described in commonly assigned U.S. Patent 3,840, as well as in one Improvement on the chemical cleaning system described in commonly assigned U.S. Patent 4,032,443.

Using frequent or excessive dry cleaning cycles Halogenated compounds can be detrimental to the operation of a biological system or to its quality of the filtrate from the wastewater treatment system. Halogenated compounds, such as those containing bromine or chlorine, can combine with hydrocarbons, which are present in the wastewater, with the formation of trihalomethanes, which are used by the environmental protection authorities as carcinogens are designated. Bromoform and chloroform are examples of halogenated hydrocarbons that result from the application halogenated compounds can resuMeren.

In Figure 9, a preferred embodiment is this Characteristic of the invention shown. An improvement to the sub-drainage system of U.S. Patent 3,840,117 is illustrated, which includes the addition of oxidation chamber 1000, inlet conduit 1100, and composite sleeves 1200 includes. The chamber 1000 is formed from an upper plate and a lower plate, which are generally in are of the same extent with a network of horizontal bars and support them. The bars in turn support the mesh, and the mesh supports the bed of granular medium. The panels are in parallel relationship by non-limiting Separate spacers. Evenly spaced sleeves 1200 extend perpendicularly through both the upper as well as the lower plates to allow the flow of a liquid or a gas in either an upward direction or in the downward direction.

Evenly spaced air distribution chambers 208 are open at the lower end and are closed at their upper end by the lower plate of the oxidation chamber.

A detergent, generally a linear one Alkyl sulfonate, is placed in the sub-drainage device.

leads. After a predetermined amount of detergent has been introduced into the sub-drainage cavity, an oxidant solution, such as hydrogen peroxide, or a gaseous oxidizing agent such as ozone, in line 1100, introduced into the chamber 1000, into the nozzle 1400 through the opening 1420 and mixed with the detergent and the filtrate solution and pushed into the air distribution chamber 208 and through the opening 1450. Alternatively, the construction of the Sleeves 1200 and the position of the openings 1450 are shown in FIGS. 10 and 11.

The detergents or detergents or surface-active agents Agents like L.A.S. are biodegradable, and oxidizing solutions, which are strong, such as hydrogen peroxide or ozone, for example, reduce the power of the mixture when they are in front upon entry into the granular medium and maintained in the mixed state prior to application in the medium will. This device protects the power of chemicals and the use of a biodegradable detergent with a strong oxidizing agent by mixing them immediately before, during or immediately after the subsequent Passing the filtrate into the medium, and yet results in a uniform Distribution of the mixture into the medium. This procedure reduces the cost of dry cleaning, excludes the formation of any trihalomethanes and the problems with emptying non-biodegradable detergents or phosphate type detergents. The chemical cleaning system quickly emulsifies any remaining Grease coating on the medium grains and washes the surface of the grains free of any fat or oil residue.

Another feature of the invention, as shown in Figure 9, is the ultimate entry of air into the sub-drainage system through line 1500 and intermittently operated valve 1510 into line 1100, resulting in a Pulse beam formation leads. This pulsating blasting removes the grease and oil film from the sand medium even more effectively.

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Claims (1)

a λ β β » Dr. F. Zumstein Sr. - Dr. E. Assm ^ jn .-. Pr. Dipl.-Ing. F. Klingseisen - Dr. F. Zumstein jun. PATENT LAWYERS STERLING DRUG INC. New York, V.St.A. Case 4665 B. Method and device for the treatment of sewage Claims 1. Process for the treatment of waste water for the removal of suspended and / or colloidal materials including possible fats and oils from a previously untreated one Waste water containing household waste water, characterized in that one a) the wastewater, which contains household wastewater, to a Clarifying or screening device directs to remove some of the materials and clarify the wastewater, without significant addition of chemicals; b) the clarified wastewater without significant addition of chemicals through a granular medium pilter within * a filter container to an underflow cavity ξ leads to form a filtrate containing less than 40% of the suspended solids present in the untreated Sewage is present; c) intermittent air up through the granular Medium conducts to reduce the flow resistance through the medium and the anaerobic biological Inhibit activity therein without destroying the integrity of the filter medium; and d) intermittently the filter with a portion of the filtrate and a surfactant and / or a Oxidizer backwashes to remove accumulated harmful materials. 2. Wastewater treatment process for removing suspended matter and / or colloidal materials, including possible fats and oils, from a previously untreated one Wastewater containing household wastewater, characterized in that that he a) the wastewater, which contains household wastewater, to a Wastewater treatment plant or screening device leads to remove some of the materials and to clarify wastewater, without substantial addition of chemicals; b) the clarified wastewater without substantial addition of chemicals through a first granular medium filter passes into a first filter container to form a primary filtrate; c) the first primary filtrate without any substantial addition of chemicals through a second granular media filter in a second filter canister to produce a secondary filtrate that is less than 25% 3Ί38246 _ ₃ - which contains suspended solids present in the untreated wastewater; d) intermittently air upward through the granular medium conducts in each filter in order to reduce the flow resistance through the medium and the anaerobic to inhibit biological activity therein without destroying the integrity of the filter medium; e) intermittently the first filter with a portion of the primary filtrate and a surfactant and / or backwash oxidizers to remove harmful materials; and f) intermittently the second filter with part of the Secondary filtrate and a surfactant and / or oxidizing agent backwashes to remove harmful Remove materials. 3. Wastewater treatment method according to claim 2, characterized in that that the effective medium grain size of the second filter is smaller than the effective medium grain size of the first filter. 4. A method for wastewater treatment according to claim 2 or 3, characterized in that the secondary filtrate is less as 30 mg / 1 suspended solids and 30 mg / 1 BOD-contains. 5. A method for wastewater treatment according to any one of claims to 4, characterized in that the medium of the second Filter is activated carbon. 6. Process for wastewater treatment to remove suspended matter and / or colloidal materials, including possible fats and oils, from a previously untreated one Waste water containing household waste water, characterized in that one a) the wastewater containing household wastewater, one Sewage treatment plant or screening device to remove some of the materials supplies to the wastewater clarify without significant addition of chemicals; b) the clarified wastewater without substantial addition of chemicals through a first granular medium filter in a first filter canister to a first sub-drainage cavity leads to the generation of a primary filtrate? c) Quickly use a coagulation chemical with the first The filtrate is mixed, and the filtrate is passed through a secondary granular media filter without a flocculation step in a second filter container leads to a second sub-drainage cavity, to create a Secondary filtrate which is less than 10% of the suspended Contains solids contained in the untreated wastewater; d) intermittently air upward through the granular medium each filter conducts to reduce the flow resistance through the medium and the anaerobic biological Inhibit activity therein without destroying the integrity of the filter medium; e) intermittently the first filter with part of the Primary filtrate and a surfactant and / or oxidizing agent is backwashed to remove accumulated harmful remove borrowed materials; and f) intermittently the second filter with part of the Secondary filtrate and a surfactant and / or oxidizer backwashed to accumulate remove harmful materials. 7. A method for wastewater treatment according to claim 6, characterized in that the secondary filtrate contains less than 20 mg / 1 suspended solids and 20 mg / 1 ₅ BOD. Methods of wastewater treatment to remove suspended and / or colloidal materials, including possible fats and oils, and reduced forms of nitrogen from previously untreated wastewater, that Contains household wastewater, characterized in that one a) the wastewater, which contains household wastewater, to a Sewage treatment plant or screening device, to remove part of the material and to clarify the wastewater, without significant addition of chemicals; b) the clarified wastewater without substantial addition of chemicals through a first granular medium filter in a first filter vessel to a first sub-effluent cavity to form.ein primary filtrate; c) the primary filtrate through a solid media or fixed Media filter conducts, whereby nitrifying microorganisms grow on these solid media, to the nitrogen in the primary filtrate to nitrate and nitrite oxidize; d) passing the nitrified primary filtrate through a second granular medium filter in a second filter vessel to a second sub-drain cavity to produce a secondary filtrate containing less than 20 mg / l suspended solids and 20 mg / l BOD ₅ ; e) intermittently air up through each granular ■ Medium passes to reduce the flow resistance through the media and to inhibit the anaerobic biological activity therein; f) intermittently the first filter with part of the Primary filtrate and a surface-active agent and / or oxidizing agent to remove accumulated backwashes harmful material; and g) intermittently the second filter with a portion of the secondary filtrate and a surfactant and / or backwashes oxidizers to remove accumulated harmful material. 9. A method for wastewater treatment according to claim 8, characterized in that the primary filtrate through the Solid medium filter with a surface loading rate equal will. equal to or above 13.6 l / min / m ² (0.34 GPM / ft ² ) 10. A method for wastewater treatment according to claim 8 or 9, characterized in that the primary filtrate through the Solid media filter is passed in a single pass without recirculation. ι. na «β ν _{Wl [} ^ j _mm · ' 11. A method of wastewater treatment according to any one of claims 8 to 10, characterized in that the temperature of the untreated wastewater is above 20 ° C (68 ° F) and the secondary filtrate contains _{less than 1.5 mg / 1 NH 4 -N.} 12. A method for wastewater treatment according to one of the preceding Claims, characterized in that the fiI-entered a natural water source without further biological Treatment other than disinfection is drained. 13. Process for wastewater treatment according to one of the preceding Claims, characterized in that the harmful materials removed from the filter or filters be removed, any carbon or carbon particles from the abrasion of the filter media originate, contained, concentrated by gravity thickening and digested anaerobically together with suspended solids removed by the sewage treatment plant or sieve device to form of fuel gas. 14. A method for wastewater treatment according to claim 13, characterized characterized in that a coagulant is added to the harmful materials removed prior to gravity thickening is added. 15. Method of wastewater treatment according to any of the preceding Claims, characterized in that the oxidizing agent is hydrogen peroxide, ozone and oxygen-containing Contains gas or a halogenated compound. 16. A method for treating waste water according to any one of the preceding claims, characterized in that the air bubbled up through the granular medium by lifting the filtrate within the Under-drain cavity is created by replacing the air in the upward direction. 17. A method for treating waste water according to any one of the preceding claims, characterized in that the filtrate from step b) has a significantly reduced potential for the production of new cell material the anaerobic biological treatment stage the biological solids are brought into contact with the filtrate. 18. A method for treating waste water according to claim 17, characterized in that the aerobic biological treatment stage includes passage through a trickle filter without recirculation of the trickle filter effluent. 19. The method according to any one of the preceding claims, characterized characterized in that the surfactant is added to the portion of the filtrate with which the filter is added is backwashed, and that the oxidizing agent is in a stream of the filtrate immediately before, during or immediately following the passage of the filtrate into the granular medium. 20. The method according to any one of the preceding claims, characterized in that the backwash is a simultaneous Spraying of filtrate and / or oxidizing agent onto the wall surfaces of the filter container for cleaning ψ ο α »· ι and disinfecting these walls. 21. The method according to any one of claims 1 to 19, characterized in that that the backwashing th of the filtrate and air with the formation of agitation at high speed and medium movement at a variable extent under the fluidization (subfluidized) includes. 22. Filtration device with granular media for removal of suspended and / or colloidal material, including fats and oils from wastewater by a first filter vessel having a bottom and side walls; a first filter bed of particulate! Material that is adjacent to the bottom of the first filter vessel and has a top surface; Sewage inlet facilities; an under-drainage cavity, under and generally coextensive with the first filter bed; Means for drainage or drainage from the sub-drainage cavity filtered wastewater after the filtered wastewater has passed through the first bed; a second filter vessel, which is smaller than the first filter vessel, with a bottom and side walls, is attached within the first filter vessel, above the first filter bed; a second filter bed of particulate! Material, adjacent to the bottom of the second filter vessel and having a top surface; a second sub-drainage cavity below and generally coextensive with the second filter bed; Means for the drainage or drainage of filtered waste water from the second sub-drainage cavity after the wastewater has passed through the second bed; Filtrate tank facilities for receiving and storing part of the filtered wastewater coming from the first and the second sub-drainage cavity has drained; Pump devices for backwashing both filter beds separately or simultaneously with filtered waste water the filtrate container devices for cleaning the filter beds and for suspending harmful material in the backwashed filtered wastewater over the two beds; Piping means for draining the backwashed filtered wastewater from over the filter beds to one separate treatment stage; Piping means for draining excess unfiltered wastewater from above the filter beds a sewage dump chamber before backwashing begins; and Pump devices to return the excess, unfiltered wastewater from the wastewater discharge chamber the inlet devices for the wastewater to be filtered. Oil «· ·· - 11 - 23. Apparatus according to claim 22, in which the waste water inlet means a sewer pipe in connection with a flow indicator, a flow indicator outlet, this outlet communicating with pipe means to the first and second filter vessels, flow control valves in the pipeline facilities, and further includes control devices in which these flow control valves are placed on the flow indicator respond and a waste water flow, which goes beyond a certain extent, to the second filter vessel conduct. 24. Lower drainage structure to support a granular medium filter bed carrier screen, this structure being above an underdrain cavity is erected in a lower part of a filter chamber, characterized by a network of transversely extending bars arranged horizontally to support the screen, an oxidation chamber formed from an upper plate and a lower plate, generally generally equal extent with and supporting the network of rods, these plates being separated by several parallel are non-limiting spacers, Evenly spatially separated sleeves or sleeves, which run vertically through the upper and lower Plates extend to allow liquid or gas to flow either up or down, evenly spatially separated air distribution chambers with lower open ends and upper ends that are generally closed by the lower plate, Means for injecting one or more Oxidizing agents, consisting of air, oxygen, ozone or other gaseous oxidizing agents or solutions of hydrogen peroxide or halogenated compounds in the oxidation chamber, and Means to immediately advance the oxidizing agent from the oxidizing chamber into the liquid upstream its passage through the screen and into the filter bed. 25. Undercross structure according to claim 24, in which the sleeves or Sleeves have through openings to enable the oxidizing agent from the oxidizing chamber - flow through the openings in the liquid upward flow.