EP2234918A1 - Reacteur et procede de production de dioxyde de chlore - Google Patents

Reacteur et procede de production de dioxyde de chlore

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Publication number
EP2234918A1
EP2234918A1 EP03738905A EP03738905A EP2234918A1 EP 2234918 A1 EP2234918 A1 EP 2234918A1 EP 03738905 A EP03738905 A EP 03738905A EP 03738905 A EP03738905 A EP 03738905A EP 2234918 A1 EP2234918 A1 EP 2234918A1
Authority
EP
European Patent Office
Prior art keywords
reactor
chlorine dioxide
reaction chamber
reactants
delivering
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03738905A
Other languages
German (de)
English (en)
Other versions
EP2234918A4 (fr
Inventor
Wilfried J. Schmitz
David Francis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BCR Environmental Corp
Original Assignee
SCHMITZ Wilfried J
BCR Environmental Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SCHMITZ Wilfried J, BCR Environmental Corp filed Critical SCHMITZ Wilfried J
Publication of EP2234918A1 publication Critical patent/EP2234918A1/fr
Publication of EP2234918A4 publication Critical patent/EP2234918A4/fr
Withdrawn legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2/00—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor
    • A61L2/16—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor using chemical substances
    • A61L2/20—Gaseous substances, e.g. vapours
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B11/00—Oxides or oxyacids of halogens; Salts thereof
    • C01B11/02—Oxides of chlorine
    • C01B11/022—Chlorine dioxide (ClO2)
    • C01B11/023—Preparation from chlorites or chlorates
    • C01B11/024—Preparation from chlorites or chlorates from chlorites
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
    • C02F1/763—Devices for the addition of such compounds in gaseous form
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/001—Upstream control, i.e. monitoring for predictive control
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/08—Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD]
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/20—Total organic carbon [TOC]
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/29—Chlorine compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/04—Disinfection

Definitions

  • the present invention relates to a novel chlorine dioxide production apparatus, or reactor, to a novel system for production of quantities of chlorine dioxide from commercial and other grades of starting materials, and to methods of using the reactor in situ, for example within a pipe containing a liquid, or separately from that pipe but air-cooled or water-cooled as needed, for bleaching, and for disinfection, decontamination, and sterilization of flows of water or other liquids.
  • chlorine dioxide destroys viruses, bacteria, and other microscopic organisms as it oxidizes compounds having a lower oxidation potential than itself.
  • chlorine dioxide is preferably added after the sedimentation tank or basin.
  • Chlorine dioxide (C1O2; CASR n 10049-04-4) is a greenish-yellow gas at room temperature that is stable in the dark but unstable in the light. As noted, it is recognized as an extremely powerful biocide, disinfectant agent and oxidizer.
  • EPA United States Environmental Protection Agency
  • Chlorine dioxide kills microorganisms by disrupting transport of nutrients across the cell wall. Chlorine dioxide can be generated in a gas or liquid form and smells like chlorine bleach. However, chlorine dioxide is not to be confused with chlorine gas. They are two distinct chemicals that react differently and produce by-products that also have little in common. Chlorine dioxide, CIO2, offers the following benefits. First, ClO 2 functions via an oxidative rather than chlorinating reaction, the mode of action of chlorine gas. This virtually eliminates the fomiation of chlorinated organic compounds that are suspected to increase certain cancer risks. Second, CIO2 when generated on site, eliminates the need for site storage of chlorine and/or transportation thereof.
  • a typical solution taught by U.S. 6,325,970B1 is a mixture comprising about 10 percent of a 28 percent sodium chlorite solution, about 10 percent of a 12 percent sodium hypochlorite solution, about 1.5 percent of a sodium hydroxide solution, and about 80 percent water.
  • acid is added; the release of chlorine dioxide is stated to be faster with stronger acid solutions.
  • the molar ratios of the chlorite and chlorine donor are set such that substantially no gaseous chlorine dioxide is formed. It appears another factor is the relatively low concentrations of the reactants, and the overall reaction conditions. While this approach provides a margin of safety by avoiding the generation of gaseous chlorine dioxide, it is limited to producing relatively low concentrations of chlorine dioxide. For instance, it is stated that a preferred embodiment yields 20,000 to 50,000 parts per million (ppm) of chlorine dioxide before dilution. This is less than five- percent active chlorine, which is very dilute for industrial and municipal bleaching and disinfection operations, respectively.
  • chlorine dioxide delivered in solution is relatively safer than chlorine gas, the gas form is more toxic and dangerous.
  • the economics of production favor the generation of the gas, there is a need to develop a system using chlorine dioxide gas in which the chance of leakage or exposure is minimized.
  • the present invention advances the art by providing a reaction chamber, a system, and methods for the production of chlorine dioxide gas for oxidation and disinfection piuposes. As described below, it advances the art by meeting 15 the needs stated immediately above.
  • the present invention relates to a novel reaction chamber useful in the 20 high-yield production of chlorine dioxide gas from commercial and technical grade reactants.
  • the present invention also is directed to a process of generating chlorine dioxide gas in the novel reaction chamber, or reactor, which preferably includes operating the reactor at specified elevated pressure and/or temperature.
  • the invention also includes systems useful for the addition of chlorine dioxide to flows in need of such compound in 25 which more than one point of addition is provided, and monitoring of more than one point along the flow provides for replenishment of chlorine dioxide at points after the initial point of addition.
  • one object of the present invention is to advance the art of chlorine dioxide generation with a new design of a reaction chamber in which commercial and technical grades of common reactants are driven to react to completion or near completion to generate high yields of chlorine dioxide gas.
  • a related object is to have the reaction chamber with an adjustable volume, which in certain embodiments permits adjustment of the chamber volume to conelate with the relative production levels of chlorine dioxide required in a particular application of the chamber. This permits a single chamber to function to produce chlorine dioxide across a wider range of outputs.
  • Another object of the present invention is to practice a method of chlorine dioxide production which involves reacting commonly available commercial and technical grade reactants under pressure and within a specified temperature range to generate high yields of chlorine dioxide gas.
  • Another object of the invention is to use the same reactor to produce oxidant species other than chlorine dioxide by using the reactor system at elevated pressure and at a selected temperature range to drive other compounds to yield desired strongly oxidizing species.
  • Another object of the present invention is to provide a means to produce chlorine dioxide in a place close to its use for disinfection of a stream of water or other liquid, to reduce the risks of toxics release and harm to workers, the environment, and nearby persons.
  • Another object of the present invention is to advance the art of production of chlorine dioxide through its production at elevated temperature and pressure by combining a chlorite source, for instance sodium chlorite solution, with an acid source, such as sodium bisulfate, and optionally also adding a halogen donor, such as sodium hypochlorite.
  • a chlorite source for instance sodium chlorite solution
  • an acid source such as sodium bisulfate
  • a halogen donor such as sodium hypochlorite
  • Figure 1 presents a generalized depiction (not to scale) of a water system to which an embodiment of the chlorine dioxide system of the present invention.
  • Figure 2 is a cross-sectional view of one embodiment of the reactor of the present invention, shown within an enlarged area of a water flow pipe into which the chlorine dioxide produced in the reactor is released.
  • Figure 3 is a view pe ⁇ endicular to the view of Figure 1, taken along the A-A axis in Figure 1, viewing toward the chamber discharge end, and bisecting each of the three reactant supply pipes.
  • Figure 4 shows a cross-sectional view of one embodiment of the reactor having an adjustable volume reaction chamber.
  • Figure 5 is a cross-sectional view of an embodiment of the reactor of the present invention, shown within an enlarged area of a water flow pipe into which the chlorine dioxide produced in the reactor is released.
  • the reactant supply lines enter the reactor chamber from one end, and the release nozzle (releasing chlorine dioxide) is at the opposite end of the reaction chamber.
  • Figure 6 is a cross-sectional view of an embodiment of the reactor of the present invention, shown within an enlarged area of a water flow pipe into which the chlorine dioxide produced in the reactor is released.
  • the reactant supply lines enter the reactor chamber from one end, and the release nozzle (releasing chlorine dioxide) is at the opposite end of the reaction chamber.
  • FIG. 7 depicts an embodiment of a reaction chamber of the present invention, which additionally comprises a bottom-positioned drain line that is suited to drain settled material from the reaction chamber and a rear positioned flushing line to be used either during operation or during clean-up of the chamber at shut-down.
  • Figure 8 is a cross-sectional view of an embodiment of the reactor of the present invention, shown within an enlarged area of a water flow pipe into which the chlorine dioxide produced in the reactor is released.
  • the reaction chamber is positioned into one of three legs of a PVC "Y' coupling, hi this particular embodiment, the reaction chamber is constructed of one piece of plastic material (such as CPNC or PTFE) that has been machined to provide the hollow cavity as a reaction chamber and three bored chemical feed entrances to this cavity. Also, spaces for check valves are provided in this single piece, and check valves are placed therein. Water inflow and outflow are through the other two legs of the "Y' coupling.
  • Figure 9 A is a cross-sectional view of an embodiment of the reactor of the present invention. This reactor embodiment is machined from a CPNC or other appropriately chemically resistant plastic block, providing three channels through which water flows, cooling the reaction chamber.
  • the chemical injection points are through three bored chemical feed entrances positioned at 120 degrees relative to each other.
  • the chemicals directly impinge and mix at a central point.
  • spaces for check valves are provided in this single piece, and check valves are placed therein.
  • Figure 9B depicts a reactor also machined from a CPNC or other appropriately chemically resistant plastic block, however machined to provide a single large channel through which water flows, cooling the reaction chamber.
  • the chemical injection points are through three bored chemical feed entrances positioned in line relative to each other. The chemicals enter in a sequential arrangement in relation to either end of the reaction chamber.
  • spaces for check valves are provided in this single piece, and check valves are placed therein.
  • Figure 10 is a diagrammatic view of an embodiment of the present invention which uses a positive-displacement pump to draw the reactants into a reaction chamber of the present invention.
  • the reactants mix, react, and the end-products, largely chlorine dioxide gas, are pumped out by the same pump.
  • Figure 11 is a diagrammatic view of an embodiment of the present invention which utilizes commercially available CPNC pipe fittings to form a reactor of the present invention.
  • a standpipe is at the gravitational bottom of the reactor so constructed, providing for a pooling or mixing effect at the bottom of the reaction chamber.
  • chemical reactant liquids are pumped into the chamber, they accumulate or pool at the bottom, react, forai chlorine dioxide which is in gas and solution form. Gas and liquid from this chamber are expelled through the opening of the standpipe, and go therefrom into the stream of the water to be disinfected.
  • Figure 12 diagrams a large water flow being disinfected at more than one point by inputs of chlorine dioxide, where the amounts added at the inputs are controlled by a centralized processing system that receives data from more than one point along the large water flow.
  • One aspect of the present invention is a novel reactor, having as a key component a reaction chamber, which are engineered to optimize the production of chlorine dioxide gas from reactions among various combinations of reactants.
  • reactants, pre-cursor chemicals, pre-cursor materials, and starting materials are defined to mean the same thing, namely, the chemicals that are passed into the reaction chamber for reaction to form the one or more products, or end-products, of the reaction.
  • pipe has its normal meaning, and "flow channel” is taken to mean a pipe as well as any open channel through which a fluid passes.
  • Typical embodiments of the chlorine dioxide system of the present invention utilize an acidified chlorite solution with the addition of an additional halogen to hasten the chlorine dioxide generation process.
  • this system utilizes a raw water pump to supply the water (carrier media) to an in-situ chemical reactor (also refereed to as a reaction chamber or generator).
  • the carrier water pump runs once the system is powered up and wastewater is flowing through the main wastewater conduit (pipe, channel, etc) of the waste stream that is being treated.
  • input data from a ClO monitor and the flow switch signal the system controller to drive the chemical feed pumps.
  • the chemical feed pumps draw their individual chemical solutions up from their storage tanks and deliver them to the chemical reactor.
  • this reactor is located within the flow of the water supplied by the raw water pump. This is done as a safety feature to assure that the chlorine dioxide goes into immediate solution preventing any potentially explosive conditions from occurring.
  • a flow switch in the raw carrier water line has the function of halting the chemical feed, hence stopping ClO 2 generation, should a loss of carrier water occur. It should also be noted that as the reactor is positioned within the carrier water stream any potential leaks or feed line ruptures will not allow escape of the chemicals beyond the contained feed water piping system and not to the atmosphere.
  • each of the chemical feed lines is equipped with a flow switch connected in series with the other flows' flow switches, so that if one flow is interrupted, all flows cease.
  • Additional safeguards that may be inco ⁇ orated into these or other embodiments include, but are not limited to: (1) high, low, and critically low level indicators on the chemical storage tanks, (2) check and foot valves on either side of the chemical feed pumps as well as chemical flow switches to assure that all three reactants are supplied to the reactor equally, (3)calibration columns on the discharge side of the chemical feed pumps, (4) check valves and a bypass arrangement around the reactor/injector to allow for service and inspection and (5) bi-directional telemetry to relay signals of the above and/or other parameters to a remote location, and to send back commands to pumps, etc. (such as for control, decision-making), and numerous other features that add to the performance of the system. Such additional features add to system reliability and safety in typical industrial workplace environments.
  • Figure 1 provides a general operational diagram of a portion of a wastewater treatment (not to scale) that shows the reactor of the present invention positioned in a wastestream.
  • Figures 2-11 only the reactor is shown; however, it is to be understood that the necessary supplies (i.e., from tanks such as shown in Figure 1) are connected appropriately to such reactors.
  • reaction I the hypochlorite reacts with sodium bisulfate to produce hypochlorus acid.
  • reaction II the hypochlorus acid so formed in reaction I reacts with additional free hydrogen ion to produce chlorine gas in solution.
  • the excess free hydrogen ion is a result of the acidic reaction condition in the reaction chamber.
  • reaction 1H the chlorine gas reacts with the sodium chlorite to produce chlorine dioxide.
  • the chlorine dioxide gas given the pressure in the reaction chamber, flows out through a pressure relief valve or other suitable orifice that allows maintenance of the desired pressure in the reaction chamber. Once in the stream of water outside the chamber, the chlorine dioxide gas dissolves in the water. Partial reaction products and reaction byproducts also exit the reactor chamber via this route, or, alternately, are removed via a passage toward the gravitational bottom of the reaction vessel.
  • the term "acidifying reactant” is used to mean and include sodium bisulfate, urea sulfate and an organic acid or a blend of two or more organic acids which, when provided to said reaction chamber, reacts with other components therein, including the aqueous media and hydrogen ions, to form or remain an acid, and thereby to maintain a desired low pH in the reaction chamber. While a preferred acidifying reactant is sodium bisulfate, and this compound is used in the examples provided below, this is not meant to be limiting to the broader scope of the invention, and of the claims in which the term "acidifying reactant" is used.
  • organic acids include, but are not limited to: acetic acid; glacial acetic acid; citric acid; lactic acid; and malic acid.
  • inorganic acids such as hydrochloric acid, may be used in place of the acidifying reactant as defined above, in the present invention. However, it has been observed that when such inorganic acid is used, the reaction is less stable.
  • Sodium Bisulfate ( ⁇ sodium acid sulfate): Typically used at 5% to 33% concentration of graduals to water by weight.
  • Sodium Chlorite Typically used at 2% to 40% of granules to water by weight. It is noted, however, that only 80% of technical grade sodium chlorite is available as sodium chlorite. That is, technical grade sodium chlorite contains about 80 percent sodium chlorite, about five percent Na2CO 3 , about two percent NaClO 3 , and about 13% NaCl.
  • Sodium hypochlorite 3%to 15% available chlorine concentrations.
  • the sodium bisulfate is an example of an acid source for the reaction
  • the sodium chlorite is an example of a chlorite source/donor for the reaction
  • the sodium hypochlorite is an example of a halogen donor for the reaction.
  • the latter is an optional, preferred reactant.
  • various substitutions by other chemicals can be made.
  • Any halogen donor can be used as a replacement to hypochlorite acid , but it has been found that the hypochlorite is more economic ,to use and readily available.
  • the injector with the occasional clean out mode removes the scaling that is formed by calcium deposits when using calcium hypochlorite as the halogen donor.
  • the system and reaction vessel may be operated either in a continuous mode, or in a pulse mode.
  • the general operating parameters of a typical reaction and reactor are as follows.
  • the input flow rate of the reactants, the reaction chamber volume, and the outflow from the reactor are adjusted so that the chamber attains a pressure at least greater than the ambient pressure of the liquid in the pipe surrounding the reactor, hi this way the reaction products (i.e., chlorine dioxide gas, minerals in solution or expelled as a diluted slurry, chlorine dioxide dissolved within the aqueous phase that largely is comprised of the combined water component of the chemical reactant solutions) are readily released into that stream of liquid on a desired continuous, semi-continuous, or pulsed basis.
  • a pressure relief valve on the reactor set to 65 p.s.i. works suitably, and is greater than the pressure in the ambient wastewater flowing around the reactor.
  • a suction pump has been effective in drawing the reactants into the reaction chamber, and pumping the products from the reaction chamber into a stream of liquid to be treated, without the requirement for an absolute positive pressure developed in the reaction vessel.
  • a positive pressure in the reaction chamber is not an absolute requirement.
  • aqueous chemical solutions that contain the reactants of the present invention's method for the production of chlorine dioxide.
  • one alternative is to procure or to prepare aqueous chemical solutions at concentrations such that pumping these at 1 : 1 (where a halogen donor is not added), or 1 : 1 : 1 (where a chlorite source, an acidifying chemical, and a halogen source are added) ratios. These solutions are then added at this simple ratio to generate chlorine dioxide.
  • a single positive displacement pump is capable of providing all three chemical solutions to a desired container for the reaction to produce chlorine dioxide. This also simplifies the adjustment of chlorine dioxide production when such production is being controlled by a feedback loop system - a signal to a single pump adjusts the levels of all two or three chemical reactants. Also, the system is less likely to operate out of the desired range of chemical reactant ratios, as may occur when each chemical reactant is supplied to the reaction container and one pump fails or deviates from its pre-set or pre- calibrated flow rate.
  • the ratio of the final reactant solutions are maintained at 1:1 or at 1:1:1, but the concentration of the chlorite source is lowered.
  • sodium hypochlorite is the halogen donor
  • sodium bisulfate is the acidifying reactant
  • sodium chlorite is the chlorite source
  • a stock solution of about 31.25 percent sodium chlorite (nominal strength) is diluted to about five percent (i.e., a 6.25-fold dilution).
  • a stock solution of 30% (nominal strength) of sodium bisulfate is used without dilution, and a 12% (nominal strength) stock solution of sodium hypochlorite is used without dilution.
  • a disadvantage to the above method is that dilution of one or more chemical reactants to adjust to the desired 1 : 1 or 1 : 1 : 1 mixing ratio results in having a larger than needed volume of that adjusted aqueous chemical reactant solution. This may be problematic at certain facilities.
  • Another operational alternative is to obtain chemical reactants at a concentration that is determined suitable for the expected pumping rates (which is determined partly on the available pumps, their accuracy, and the expected demand of chlorine dioxide from the process), and then pump such suitable concentrations separately, at ratios other than 1 : 1 or 1 : 1 : 1.
  • an option is to monitor flow rate cessation by each chemical reactant solution pump, and shut down the entire system shut down if one fails.
  • Another control mechanism is to have a control feedback loop that adjusts the pumping rate of one or more pumps based on a parameter of the system being out of a desired range.
  • the actual concentration of the halogen donor when sodium hypochlorite is the halogen donor, may vary and not adversely affect the output of the method. For instance, it is recognized that sodium hypochlorite is unstable and a 12 percent nominal strength stock solution tends to test at a lower actual concentration over time. However, at a pumping ratio of 1 : 1 : 1 , it has been established that even when the actual sodium hypochlorite concentration of the 12 percent nominal strength stock solution drops to as little as 2.5 percent, a reaction still proceeds favorably when this is mixed at the 1:1:1 ratio with 30% (nominal strength) sodium bisulfate and 31.25 percent (nominal strength) sodium chlorite.
  • the most preferred pH range, particularly for continuous operation reactors is from about 2.0 to about 2.5 pH units. It is noted that for semi-continuous and pulse reactor regimes, the pH fluctuates as the acidifying reactant enters and reacts in the chamber. Also, it has been observed that, when all other parameters are held constant, an increase in the volume of the reaction chamber results in an increase in pH of the chemical mixture in the reaction chamber.
  • a prefened range of operating temperature is between about 40 degrees Fahrenheit and about 155 degrees F.
  • a more prefened range is from about 60 to 120 degrees F, a more preferred range is from about 60 to 100 degrees F, and the most prefened temperature range is from about 80 to about 90 degrees F.
  • sodium bisulfate stock solution should be maintained at or above about 45 degrees Fahrenheit. This has been found to prevent precipitation of salts, and eliminates crystallization in the stock solution storage container and in the feed lines.
  • the reactants may at times yield a build-up of calcium or other metals within the reactor. This may be caused where the water to be treated contains high levels of calcium and/or other metals, such as iron. These metals may precipitate out and build up as scale within the reactor.
  • an additional input, or feed line is introduced into the reactor. This allows for a chemical flushing of the reactor. Such flushing is done with an acid such as the bi-sulfate used in the reaction process. The frequency of the flushing is dependent upon the levels of precipitants in solution.
  • sodium bisulfate in the production of chlorine dioxide is unexpected, as sodium bisulfate is known to be useful in the reduction and removal of chlorine disinfectant compounds. Accordingly, it is counter-intuitive to use sodium bisulfate as a component in the production of chlorine dioxide. Further, in that the reactions described in this invention are far less exothermic than other reactions used to produce chlorine dioxide, the reactions and reaction systems of the current invention are more amenable to in situ and small scale, efficient, and cost-effective production of chlorine dioxide.
  • the present invention is described in certain examples below as being used to disinfect the effluent in wastewater treatment plants, it is recognized that the present invention has numerous other applications and is quite versatile.
  • the reactions, apparatuses, methods and systems of the present invention maybe used to dismfect or otherwise treat not only the effluent of wastewater treatment plants, but also the following:
  • ballast water of ocean-going ships to kill the larval and adult stages of exotic species that may have been pumped into the bilge at a foreign port, prior to discharging such ballast water at another port (to prevent environmental problems such as the zebra mussel in the United States);
  • SARS severe acute respiratory syndrome
  • the reactor, 20, is comprised of a reactor body, 3, which is preferably cylindrical in cross-section but may be of any three-dimensioned shape such that it has sufficient space for the reaction, and sufficient strength to withstand pressures and temperatures to which it is exposed.
  • the reactor, 20, also is comprised of a reaction chamber, 22, situated within the reactor body, 3. Insulation, 24, fills the space between the outer walls of the reaction chamber, 22, and the inner walls of the reactor body, 3. It is noted that in other embodiments the reactor body, 3, serves as the reaction chamber itself, and there is no space for intervening insulation.
  • a heater, 6, is provided. As shown in Figure 2, there is no insulation between the heater, 6, and the adjacent bottom surface of the reaction chamber, 22. It is noted that in other embodiments a heater is not present and insulation may occupy all spaces between the reactor body, 3, and the reaction chamber, 22, except where there are structural supports, inlets and outlet pipes, and other structural or control features.
  • each of the three pipes, 1, 4, and 5 pass through the reactor body, 3, and open into the reaction chamber, 22.
  • each of the three pipes, 1, 4, and 5 carry a different reactant into the reaction chamber, 22.
  • these pre-cursor chemicals are delivered under pressure to the reaction chamber, 22, and the reaction chamber, 22, also is under pressure.
  • an adjustable pressure actuated check (one-way) valve (not shown in Figure 2) is present in each of the supply pipes supplying the reaction chamber, 22.
  • the reactor, 20, is oriented to have a functional top and bottom. As shown in
  • FIG. 2 the bottom is where the heater, 6, is located. Emanating from the top area of the reaction chamber, 22, is an exit pipe, 26, that passes through the reactor body, 3. Attached at or near the end of the exit pipe, 24, is a discharge check valve, 2. Preferably, this discharge check valve, 2, is adjustable as is the one in Figure 2. Other orientations as could be designed by one of skill in the art can be envisioned that are within the scope of the present invention. For instance the reactor could be positioned in a generally horizontal fashion and have an exit pipe curved upward with a discharge check valve positioned at the distal end of the pipe. This would represent the functional top (the point at which the product is released under pressure), while the adjacent side closest to the ground or floor would represent the functional bottom.
  • the reactor, 20, is positioned within an expanded section of pipe carrying water that is to be disinfected by the chlorine dioxide produced in the reaction chamber, 22.
  • the expanded pipe section, 7, has an approximate diameter that results in a cross-sectional water flow area in section 3O that is about the same as the cross-sectional water flow area of the inflow and outflow pipes, 32 (not shown) and 34, respectively, that are before and after the expanded pipe section, 7, that contains the reactor, 20.
  • the respective cross-sectional areas of areas 30, 32, and 34 are set to help effectuate the desired level of laminar flow or non-laminar turbulent flow, and the consequent speed of mixing of the liquid with the chlorine gas.
  • Other methods of controlling laminar flow and/or turbulence as are known in the art of hydraulic flow mechanics, may also be applied.
  • Figure 3 depicts a cross-sectional view of the reactor, 20, and associated structures taken along lines A-A of Figure 2. Shown in Figure 3 are the cross-sections of the expanded pipe section, 7, the reactor body, 3, the reaction chamber, 22, the exit pipe, 26, and the discharge orifice, 11. Laterally bisected in this view are three supply pipes, 1, 4, and 5.
  • the reactor, 20, described above operates in one embodiment of the methods of this invention as follows.
  • Three pre-cursor chemicals one from each of the three supply pipes, 1, 4, and 5, are pumped into the reaction chamber, 22, under pressure.
  • the three pre-cursor chemicals are sodium hypochlorite (a halogen donor), sodium chlorite (a chlorite donor), and sodium bisulfate.
  • the sodium bisulfate is acidic and its relative level of addition is adjusted to help control the rate of the reaction to chlorine dioxide. Further, while not being bound to a particular theory, laboratory experiments and field trials appear to indicate that the addition of sodium bisulfate reduce the levels of undesirable residuals in the product mixture.
  • the relative concentrations of the three pre-cursor chemicals are sodium chlorite, sodium bisulfate, and sodium hypochlorite, are adjusted to permit a desired outcome as far as the concentration and yield of chlorine dioxide, and the nature of the reaction byproducts.
  • urea sulfate, or any organic acid blend can be substituted for sodium bisulfate.
  • hypochlorous acid may be substituted.
  • the pumps used to pump the pre-cursor chemicals through pipes, 1, 4, and 5 are positive displacement pumps, or other pumps capable of delivering the pre-cursor materials (typically solutions) under pressure against a back pressure in the reaction chamber, 22. This serves to build pressure to a desired level.
  • the discharge check valve, 2, sets the high end of pressure in the reaction chamber, 22, in that once pressure builds as a result of the pumps delivering the pre-cursor materials, and as a result of the reactions taking place in the reaction chamber, 22, the discharge check valve, 2, opens at its set pressure point, releasing chlorine dioxide (and, typically, water in the form of steam or spray liquid, which was the solvent for the pre-cursor chemicals supplied through pipes, 1, 4, and 5).
  • the reaction chamber can be operated by setting the rates of the pumps delivering the pre-cursor materials (reactants), by monitoring the level of chlorine dioxide that is discharged, and by periodically adjusting the pump rates for each of the pre-cursor materials (reactants) until a desired, acceptable or targeted production rate and/or efficiency is obtained.
  • a microprocessor, a special-p pose computer, or a general-pu ⁇ ose computer appropriately programmed for the ptupose may be operatively linked to the pumps, and to one or more detectors or sensors of chlorine dioxide (or other parameter, including but not limited to total oxygen demand, chemical oxygen demand, total organic carbon, or biological oxygen demand) downstream of the discharge of chlorine dioxide into the flow of liquid into which it was discharged from the reaction chamber. So linked and programmed, this can automatically monitor the desired endpoint parameter and adjust the rates of inputs of the reactants to reach and/or maintain a desired, acceptable or targeted production rate and/or efficiency.
  • a delivery tube is added for the addition of solids as needed.
  • the range of operating temperature is about 40 to about 185 degrees Fahrenheit.
  • a narrower but acceptable operating range is about 75 to about 145 degrees Fahrenheit, and an even narrower but acceptable operating range is about 75 to about 120 degrees Fahrenheit.
  • the operating temperature range for a particular application of the reactor of the present invention will depend upon a number of factors, including but not limited to the quality and grade of the pre-cursor chemicals, the types and levels of particular contaminants, the desired output (balancing yield with production of certain byproducts, etc.), the system into which the product is being dispersed, and the regulations in place regarding levels of residuals and contaminants.
  • the range of operating pressure is about 25 to about 200 pounds per square inch (psi).
  • a narrower but acceptable operating range about 30 to about 90 psi, and an even narrower but acceptable operating range is about 40 to about 75 psi.
  • the operating pressure range for a particular application of the reactor of the present invention will depend upon a number of factors, including but not limited to the quality and grade of the pre-cursor chemicals, the types and levels of particular contaminants, the desired output (balancing yield with production of certain byproducts, etc.), the system into which the product is being dispersed, and the regulations in place regarding levels of residuals and contaminants.
  • the level of chlorine dioxide output can be regulated by modulation of the amount of sodium hypochlorite (a halogen donor), by adjusting the strength of this solution entering the chamber, the delivery rate by the pump inputting this pre-cursor material, or by any other mechanism of modulation known to those of ordinary skill in the art.
  • Another approach to control output is to adjust the volume of the reaction chamber itself. One way to do this is shown in Figure 4, in which a bottom section, 302, of the reaction chamber, 22, is rotatably screwable into the body of the reactor body, 3.
  • the volume of the reaction chamber, 22, is adjusted initially by screwing the bottom section, 302, inward or outward to decrease or increase the volume of the reaction chamber, 22. Further adjustment may be made as needed after the performance of the unit is assessed.
  • This type of adjustment which is not limited to the disclosed screw-bottom mechanism, permits a single chamber to function to produce chlorine dioxide across a wider range of outputs.
  • chlorine dioxide can be produced through the reaction of only two reactants, namely sodium chlorite and sodium bisulfate. For instance, using stock nominal concentrations of 20 percent or 31.25 percent sodium chlorite in combination with 22 percent sodium bisulfate, chlorine dioxide was produced in the reaction chamber. Thus, a halogen donor is not an absolute requirement when these reactants are used at or around these concentrations. Therefore, it is believed that over a range of concentrations and conditions, such as can be determined without undue experimentation by one of ordinary skill in the art, a wide range of respective concentrations for sodium chlorite and sodium bisulfate can be determined at which acceptable yields of chlorine dioxide are obtained, without the need to add a halogen donor.
  • a halogen donor such as sodium hypochlorite or hypochlorous a-cid may be used initially, and then its addition suspended once the reaction is established and a sufficient quantity of halogen donors (formed as products) exist in the reaction chta ber.
  • substitution of urea sulfate, or any organic acid blend, for sodium bisulfate may also yield chlorine dioxide when combined with sodium chlorite.
  • the reactor and the system can be modified to provide suitable species of residual chlorine.
  • chloramine species may be desirable to provide more persistent second-ary disinfection well beyond the chlorine reactor, 20.
  • one variation of the above method is to add a proportionate amount of ammonia. This typically is done with a separate supply pipe, entering the water stream downstream of the reaction chamber, 22, going directly into the flow of liquids after the chlorine dioxide has been added from the reaction chamber (not shown in Figure 1).
  • the location of the supply pipe for such addition of ammonia typically is placed at a downstream point at which the chlorine dioxide has become well dispersed into the flow. While not being bound to a particular theory, it is believed that the ammonia binds with excess free chlorine and thereby forms chloramines. These chloramines are preferable to more toxic undesired byproducts, such as TTHMS and HAAS, and as noted perform as a residual chlorine species to provide secondary disinfection in the distribution pipes.
  • FIG. 1-3 placed the reactor within a larger pipe carrying the flow of liquid which was the major flow to be treated with the product of the reactor. This adds a safety factor in that the product is produced very close to where it is substantially diluted to the final concentration for disinfection, bleaching, etc.
  • the reactor alternatively can be placed apart from the major flow pipe or channel into which the product is to be distributed.
  • the reactor can be outside of any pipe carrying a liquid into which the product is released.
  • the point of release of the product for instance chorine dioxide as described in the reactions above, can be situated within a flow of liquid. This is done, for example, by positioning the reactor close to the pipe or channel carrying the flow of liquid, and positioning a pipe bearing the reactor discharge pipe in that flow of liquid.
  • flow of liquid may be the major flow pipe or channel (i.e., the , ultimate destination, in which the final diluted concentration is achieved), or that flow of liquid may be an intemiediate stream which is thereafter distributed to a larger flow as a "stock solution” or “concentrate” of the product, hi the latter case, the intermediate stream is then distributed to one or more entry points of the larger flow (e.g., the ultimate destination).
  • introduction of product into a "stock solution" intermediate flow stream this can be done as described above, from a reactor not positioned within the pipe carrying this flow stream, or, alternatively, the reactor can be placed within the pipe or other vessel carrying the intermediate flow stream.
  • the intermediate flow stream is directed to one or more sites of release into a larger flow stream, at which point the product becomes accordingly diluted.
  • the reactors, 20, are shown in expanded regions of pipe, i.e., the expanded pipe section, 7.
  • the water pipe need not be expanded at the section where the reactor, 20, is placed.
  • a relatively large pipe diameter, where the reactor's cross-sectional area is less than twenty percent of the water pipe's cross-sectional diameter the water pipe preferably is not expanded at the section where the reactor, 20, is placed.
  • Figure 4 is a cross-sectional view of an embodiment of the reactor of the present invention, shown within an enlarged area of a water flo V pipe into which the chlorine dioxide produced in the reactor is released, hi this embodiment the reactant supply lines, 1, 4 and 5, enter the reactor chamber from one end, and the discharge check valve, 2 (releasing chlorine dioxide), is at the opposite end of the reaction chamber.
  • the exit pipe, 26, is centrally located at one end of the reaction chamber, 22.
  • FIG. 5 is a cross-sectional view of an embodiment of the reactor of the present invention, shown within an enlarged area of a water flow pipe into which the chlorine dioxide produced in the reactor is released.
  • the reactant supply lines enter the reactor chamber from one end, and the release nozzle (releasing chlorine dioxide) is at the opposite end of the reaction chamber.
  • Two reactant lines i.e.., supply lines
  • 4 and 5 empty into the reaction chamber closer to the far left end of the reaction chamber, 22, allowing a longer and earlier reaction association of the chemicals from these reactant supply lines, 4 and 5.
  • the third line supply line, 1, empties into the reaction chamber at a position farther into the reaction chamber.
  • Such orientation of the feed lines is appropriate where it is desired to have two reactants, such as a the chloride source, like sodium chlorite from supply pipe 4, and an acid source like sodium bisulfate from supply line 5, initially react for a period prior to exposure to the chlorite donor, such as sodium chlorite, which enters more centrally in the reaction chamber, 22, through supply pipe 1.
  • This sequencing of reactants also is shown in Figure 6.
  • Figure 7 has both a top-positioned fourth supply pipe, 60, and a bottom-positioned drain line, 62 that is suited to drain settled material from the reaction chamber.
  • the drain pipe, 62 may operate either during operation or during clean-up of the chamber at shut- down. For instance, it may be used in conjunction with the periodic addition during operation of a strong acid via the top-positioned fourth supply pipe, 60. This periodic addition serves to dissolve and remove build-up of mineral deposits (svich as when a calcium bisulfate or a calcium chlorite is used) that may be occurring within the reaction chamber, 22.
  • the top-positioned fourth supply pipe, 60, and the bottom-positioned drain line, 62 may be added independently or together to any configuration of reaction chamber in which their respective functions are needed.
  • Figure 8 is a cross-sectional view of an embodiment of the reactor of the present invention, shown within an enlarged area of a water flow pipe into which the chlorine dioxide produced in the reactor is released, h this embodiment the reaction chamber is positioned into one of three legs of a PNC "Y' coupling, hi this particular embodiment, the reaction chamber is constructed of one piece of plastic material (such as CPNC or PTFE) that has been machined to provide the hollow cavity as a reaction chamber and three bored chemical feed entrances to this cavity. Also, spaces for check valves are provided in this single piece, and check valves are placed therein. Water inflow and outflow are through the other two legs of the "Y' coupling.
  • plastic material such as CPNC or PTFE
  • Figure 9 A is a cross-sectional view of an embodiment of the reactor of the present invention.
  • This reactor embodiment is machined from a CPNC or other appropriately chemically resistant plastic block, providing three channels through which water flows, cooling the reaction chamber.
  • the chemical injection points are through three bored chemical feed entrances positioned at 120 degrees relative to each other. The chemicals directly impinge and mix at a central point. Also, spaces for check valves are provided in this single piece, and check valves are placed therein.
  • Figure 9B depicts a reactor also machined from a CPNC or other appropriately chemically resistant plastic block, however machined to provide a single large channel through which water flows, cooling the reaction chamber.
  • the chemical injection points are through three bored chemical feed entrances positioned in line relative to each other.
  • the chemicals enter in a sequential arrangement in relation to either end of the reaction chamber.
  • spaces for check valves are provided in this single piece, and check valves are placed therein.
  • Figure 10 is a diagrammatic view of an embodiment of the present invention which uses a positive-displacement pump to draw the reactants into a reaction chamber of the present invention.
  • the reactants mix, react, and the end-products, largely chlorine dioxide gas, are pumped out by the same pump.
  • FIG 11 is a diagrammatic view of an embodiment of the present invention which utilizes commercially available CPNC pipe fittings to form a reactor of the present invention.
  • a standpipe is at the gravitational bottom of the reactor so constructed, providing for a pooling or mixing effect at the bottom of the reaction chamber.
  • chemical reactant liquids are pumped into the chamber, they accumulate or pool at the bottom, react, form chlorine dioxide which is in gas and solution form. Gas and liquid from this chamber are expelled through the opening of the standpipe, and go therefrom into the stream of the water to be disinfected.
  • Figure 12 diagrams a large water flow being disinfected at more than one point by inputs of chlorine dioxide, where the amounts added at the inputs are controlled by a centralized processing system that receives data from more than one point along the large water flow.
  • the flow of water passing the in situ reactor may be from either direction, that is, from the non- nozzled end or from the nozzled end.
  • a reactor, 400 is positioned along a pipe, 402, that originates from a source (i.e., a well or municipal supply system).
  • a pump, 406 pressurized the system if the pressure is not sufficient from the source, 404.
  • Chemical inputs (not shown) supply the reactants to the reactor, 400, and the product, chlorine dioxide, is added to the pipe, 402, at or near the site of the reactor, 400 (depending on which of the above described configurations are used to position the reactor in relation to the pipe).
  • a major flow channel, 410 in need of receiving the product, in this example being chlorine dioxide, receives a primary dosage of product through pipe 420.
  • the flow of intermediate concentration liquid from pipe 402 through pipe 420 into point A of the flow in major flow channel 410 is controlled by a controller, 422.
  • the controller may be a metering pump, a solenoid controlled valve, a metering valve, or any other means of regulating fluid flow such as known to those of ordinary skill in the art.
  • the chlorine dioxide is consumed as the flow moves to sampling point 426. At that point samples as taken, filtered as needed through an appropriate filter, for instance a 10-micron particle filter, and analyzed in detector Dl for residual levels of chlorine (in the form of chlorine dioxide). Signals of such results are transmitted to 415.
  • a signal is sent, as needed, to boost the level of chlorine dioxide in the flow in 410 by adding additional concentrate from pipe 402 through pipe 430, which is controlled by controller 432.
  • the controller receives signals from 415, which regulates how much, if any, concentrate is added through pipe 430.
  • the signals from the detectors or from other sensors may be communicated by any way known to those of skill in the art.
  • the signals can be communicated by conventional means, such as by sending electrical impulses along a conducting wire, fiber optics, by more sophisticated means, such as by converting the signals into radio waves and transmitting these waves such that a receiver receives the signals and thereafter sends them to the microprocessor (i.e., any means of telemetry), special-pmpose computer, or general pu ⁇ ose computer represented in Figure 12 as 415, or by any other way now known or later developed.
  • signals between 415 and each controller may likewise be communicated by any way now or later developed.
  • the present system and methods include a step of destroying excess chlorine dioxide or other oxidants present in a flow of liquid by exposing such flow to ultraviolet light of sufficient intensity.
  • a need may exist in a particular application of the present reactor, system and methods of production of chlorine dioxide, to reduce the level of chlorine dioxide after a certain point in the system. For instance, after sufficient residence time of exposure to chlorine dioxide, a liquid maybe effectively disinfected. Excessive reactive chlorine dioxide in the liquid stream after that point may lead to excessive corrosion, toxicity to users, or other undesired consequences.
  • a preferred way to reduce the concentration of chlorine dioxide in this case is to outfit a vessel or tank or chamber with a single or an array of ultraviolet lamp(s) mounted to expose the flow of the liquid to ultraviolet radiation at sufficient levels, based on the flow rate and depth of the flow past the lamp or lamps, to remove the necessary quantity of excess chlorine dioxide. It is widely known that ultraviolet radiation does not effectively penetrate water beyond a certain depth, depending on the intensity of the radiation and other factors. Accordingly, the flow and depth are adjusted to provide the necessary exposure time to the ultraviolet radiation to be effective.
  • a patent, U.S. patent number 6,171,558, deals with the use of ultraviolet radiation for another application. For the background provided in that patent, it is inco ⁇ orated by reference into this disclosure. Further, based on the information in U.S. patent number 6,171,558, the frequency of ultraviolet radiation to break up chlorine dioxide into chlorites and chlorates, to control high levels of chlorine dioxide, is likely above 30 nannohertz.
  • a two-phase on-site study investigated embodiments of the presently described invention system and apparatus for generating aqueous chlorine dioxide (ClO 2 ) for the disinfection of municipal wastewater.
  • the first phase described in this example, was directed to preliminary testing to target dosage levels that would provide sufficient disinfection whilst obtaining acceptable end-of-pipe, effluent toxicity based on bioassays using representative marine/estuarine test organisms.
  • the first phase also included the testing of a small-scale replica of the plant operation (post clarifier).
  • the second phase described in the next example, used embodiments of the system and apparatus of the present invention to disinfect the actual wastestream of a municipal wastewater treatment plant ("WWTP"). This study took place on site at two WWTPs in Florida.
  • CIO2 was injected into post clarifier effluents in a laboratory environment to determine the dosing requirements needed for effective bacterial control. After the desired disinfectant levels were achieved, marine organisms were subjected to these treated effluents to observe their survivability.
  • post clarifier a small-scale replica of the plant operation (post clarifier) was constructed as a side stream project. This small-scale pilot successfully operated under a wide range of actual operational variables that occu ⁇ ed in the plant during numerous test periods. Desired disinfectant levels were maintained during these tests without impacting the plant's final discharge water quality.
  • the initial study began with the sampling of post clarifier effluent to determine the bacterial count prior to standard chlorination at the WWTP. Numerous samples were taken over several weeks and diluted with de-ionized (Dl) water at a 100 to 1 ratio. These samples were then cultured, incubated and analyzed for their bacterial concentrations. It was determined that the bacterial count was ranging from 12,000/lOOml to 24,400/ml.of effluent, or an average of approximately 18,000/100ml of effluent. With this information, samples of the post clarifier effluent were dosed with CIO2 in the laboratory to determine the most effective dosage rate to effectively control bacteria. The dosing ranged from 0.3 ppm to 3.0 ppm.
  • Samples were again taken over a 7-day period to assure repeatability and to accurately determine the CIO2 dosing rate for the eventual side stream pilot.
  • Test species were the mysid shrimp, Mysidopsis bahia, and the inland silverside minnow, Menidia beryllina. With this accumulated data, the plant's operation (post clarifier) was replicated in scale. The source water for the side stream pilot was water coming from the clarifier. This water was then to be dosed to evaluate the effectiveness of the CIO2 generator and its ability to replicate the dosing rates established earlier in the laboratory samplings.
  • the pilot consisted of the following equipment: (1) a raw water pump, (2) the CIO2 generator, (3) a mixing chamber, (4) a contact chamber with 2 and 5 minute sampling points, (5) contact reservoir to allow an additional 30 minutes of contact time, and (6) an aeration basin.
  • the reactor used was constructed of CPNC pipe of 2 inch nominal diameter, and was approximately 3-4 inches long. This was placed within a water flow pipe having a nominal diameter, in the expanded section, of 4 inches (before and after which, the water pipe diameter was 2 inches). This carrier water was set to 15 gpm.
  • the chemical reactant feed pump was set at approximately 40-50 strokes per minute, with a per stroke volume about 0.8 mL.
  • the sodium bisulfate stock was approximately 30% technical grade solution, the sodium chlorite stock solution was approximately 18%, and the sodium hypochlorite nominal concentration was between about 4 and 12.5 %.
  • the wastewater stream being treated averaged about 1.8 MGD.
  • the flow rates of chemicals to the reactor of the present invention was set to achieve a complete fecal coliform kill, which was based on data from previous post clarifier testing. At this time, samples were taken from the 2- minute and the 5-minute contact point in the replicated contact chamber. These samples were studied for their disinfection characteristics and for their fecal coliform kill. Although most of the samples tested confirmed effective kills, some of the samples did not.
  • Tables l(b, c, d) illustrate the fecal kills at the variable dose rates along with the pH and the residual at the 5 minute contact time mark.
  • PH (I) is the initial pH, pH at the 48-hour mark, pH (R) after the renewal, pH at the 96-hour mark.
  • Salinity is indicated in parts per thousand initially at the 48-hour mark.
  • Cond. stands for conductivity in microhms.
  • Alk. is alkalinity.
  • Table 3(c) illustrates the survivability of the organisms at the 96-hour end-point in the test for each of the 4 samples taken (samples indicated by date and time each sample was taken.).
  • WWTP 2 was of approximately the same size as WWTP 1, operated under much the same criteria, and discharged much of its effluent into a marine estuarine water body and therefore also had mysid shrimp and silverside minno ⁇ vs as the bioassay test species. Discussion and results of the pilot evaluation at WWTP 2 are provided in Example 6, below.
  • WWTP 1 with the exception of the post clarifier bacterial counts.
  • WWTP 1 averaged a count of 18,000 cfus/lOOml, while the WWTP 2 had an average of 8,500 cfus/lOOml. This was determined to be the result of the improved aeration process (by diffused air) resulting in an improved nitrogen cycle. The ammonia levels at this plant seldom exceeded 0.2 p/ml and the chloramine formation was considerably less.
  • Clarifier Sample points 1 through 4 are the following: 1 is at the beginning of the chlorine contact chamber, 2 is at the mid-point of the chamber, 3 is at the end of the chamber and 4 is at the aeration basin.
  • TNTC too numerous to count Wednesday 31 July 2002
  • a chlorine dioxide reactor of the present invention with all needed supply tanks, feed lines and pumps, was set up at the WWTP 2 in much the same position as it was at WWTP 1 (post clarifier at the contact chamber).
  • the point of the ClO 2 injection is refened to as the Parchall flume.
  • the water leaving the clarifiers enters a chamber and spills over through the nanowmg Parchall flume where the CIO2 is mixed into the water
  • B Bromoform
  • C Chloroform
  • BDC Bromod ⁇ chloromethane
  • CDB Chlorod ⁇ bromomethane
  • TTHMS (Total THMS)
  • Tables 11, 12 are summaries of the results of the bioassay data from Laboratory 4. The complete toxicological study as reference is included as attachment at the end of this study.
  • Table 11 is a summary of the Toxicity data from Laboratory 4.
  • Table 13 is water quality data for the second set of Bioassays
  • Tables 14 and 15 are summary data from Laboratory 4. The complete toxicological results are provided at the end of this study as attachments.
  • WWTP 1 treats wastewater at one location.
  • the plant is a 5.0 mgd AADF complete mix activated sludge wastewater treatment facility consisting of two (2) 1.2 mgd aeration basins, two (2) 0.76 mgal secondary clarifiers, with chlorine disinfection and de- chlorination.
  • the permitted capacity has been 4.5 mgd, and is being changed to 4.950 mgd for the new permit period.
  • Residuals are aerobically treated in two (2) 0.36 mgal sludge holding tanks, dewatered and hauled to several locations as Class B Sludge.
  • the plant is capable of feeding 2,000 pounds per day (lbs/d) of chlorine, which is delivered and stored in one (1) ton steel cylinders. These cylinders are pressurized; therefore, the chlorine is mainly in the liquid state, with a gaseous headspace.
  • the gaseous chlorine is drawn from the cylinder, piped to the chlorinator, dosed into the stream and maintained in the chlorine contact chamber where some is used within the plant and the rest is de-chlorinated with sulfur dioxide.
  • the average design dosage for the facility is 0.5 to 1.0 mg/1 (ppm) in the chlorine contact chamber and a de-chlorinated residual of 0.01 mg/1 (ppm). This plant is permitted to surface discharge its final effluent into the Matanzas River (Class HI Marine Waters).
  • WWTP 2 is described as a 4.0 mgd.
  • AADF complete mix activated sludge wastewater treatment facility with chlorination disinfection, dechlorination and post aeration.
  • the facility includes tertiary up flow filters to a 0.8 mgd.
  • AADF for effluent for a part m (non restricted public access) reuse followed by chlorine injection to meet high- level disinfection requirements.
  • Disinfection is accomplished using a sodium hypochlorite solution. Residuals are thickened with a belt thickener and stored in an aerobic digester prior to dewatering with a belt filter press. The dewatered residuals are hauled to a regional residuals disposal facility.
  • Recent instrumentation changes that have been implemented at the facility are the installation of a turbidimeter and a total chlorine analyzer at the secondary treatment contact chamber, a pH meter/analyzer at the secondary treatment aeration basin, and a total residual chlorine analyzer and pH meter/analyzer at the Marsh Creek Country Club Golf Course Reuse Pond.
  • This facility is permitted to surface discharge to the Matanzas River (Class HI Marine Waters) and a slow-rate public access reuse (R001) system for the irrigation of the Marsh Creek Country Club Golf Course.
  • Chlorine has historically been the primary choice for disinfection of wastewater in the United States. The advantages to using chlorine are primarily cost, availability, and its known performance as a disinfectant. There are, however, certain drawbacks to the use of chlorine. Chlorine interacts with organic compounds present in wastewater to fonn undesirable disinfection byproducts THMs and HAAs. Many of these byproducts, such as chloroform, bromoform, di and tri chloro acetic acids, have carcinogenic properties and have been linked to potentially harmful long-term health effects. Chlorine's effectiveness is greatly diminished when it is used outside a narrow pH range (from pH 7-8).
  • Bio-Chem Resources' new method of CIO2 generation is a highly effective disinfectant that meets and exceeds the requirements of WWTP 1 and WWTP 2 for bacterial control in wastewater. Desired disinfectant levels were achieved and maintained over a wide range of operational variables that occurred at these facilities during testing periods. It should be noted, however, to achieve maximum benefit from chlorine dioxide disinfection (or any other disinfection process), a treatment plant needs to maintain good operational procedures. Disinfection by-products (THM's and HAA's) were also significantly reduced during these same test periods. Furthermore, repeated tests of subjecting marine organisms to the above CIO2 treated effluents showed no toxicological effect.

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Abstract

La présente invention a trait à un nouvel appareil ou réacteur de production de dioxyde de chlore. Le réacteur reçoit des réactifs en provenance d'au moins deux conduites d'alimentation sous pression, et les réactifs réagissent dans une chambre de réaction qui fonctionne sous une pression élevée et à l'intérieur d'une plage de température déterminée. Un produit gazeux, tel que le dioxyde de chlore, est généré et délivré directement dans une flux liquide pour le blanchiment, la désinfection, et à d'autres fins. L'invention a également trait à un nouveau système pour la production de quantités de composés chlorés à partir matériaux de départ de qualité commerciale, et à des procédés d'utilisation du réacteur in situ pour le blanchiment, et pour la désinfection, la décontamination, et la stérilisation de débits d'eau ou d'autres liquides. L'invention a trait en outre à un système automatisé pour une pluralité de points d'addition de dioxyde de chlore à un flux sous traitement.
EP03738905.3A 2003-05-23 2003-05-23 Reacteur et procede de production de dioxyde de chlore Withdrawn EP2234918A4 (fr)

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WO2009077213A1 (fr) * 2007-12-19 2009-06-25 Infracor Gmbh Procédé de traitement d'eau avec du dioxyde de chlore
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WO2011086579A1 (fr) * 2010-01-18 2011-07-21 Prophylaxis Procédé de production d'une forme liquide stable et pure de dioxyde de chlore
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US11535541B2 (en) 2017-02-27 2022-12-27 Ecolab Usa Inc. Method for onsite production of chlorine dioxide
TWI751311B (zh) 2017-03-24 2022-01-01 美商藝康美國公司 低風險的二氧化氯現場產生系統
UY37638A (es) 2017-08-17 2019-02-28 Ecolab Usa Inc Sistema de generación in situ de dióxido de cloro de bajo riesgo
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CA2539984A1 (fr) 2005-09-22
EP2234918A4 (fr) 2015-02-25
WO2005087657A1 (fr) 2005-09-22
MXPA05012626A (es) 2006-08-23
WO2005087657A8 (fr) 2005-12-15
WO2005087657A9 (fr) 2005-10-27
AU2003245268A1 (en) 2005-09-29

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