Abstract: A system for regulating the addition of lime to reduce water alkalinity includes two sensors for measuring the conductivity of the water prior to and after addition of lime, a pump for adding lime to the water, and a controller for regulating the pump. The controller periodically samples the conductivities measured by both sensors and computes the ratio of the conductivities for each sample as well as the slope of the ratio between samples. The controller turns the pump off when the conductivity ratio exceeds a predetermined maximum set point and the slope is positive, and turns the pump on when the conductivity ratio falls below a predetermined minimum set point and the slope is negative.

Abstract: Suspended substances, such as active sludge, in a liquor is treated in an apparatus for treating the liquor by predicting a suspension state on the basis of an amount of existing suspended substances in the liquor.

Abstract: A flocculation system for water treatment facilities comprises a flocculation tank having a plurality of baffles which divide the interior of the flocculation tank into a plurality of compartments. The baffles are arranged to provide intercompartmental openings between adjacent upstream and downstream compartments, which, in turn, are arranged to provide a serpentine flow path through the flocculation tank. A mechanical mixer is mounted in each compartment for supplementing the mixing energy provided by the serpentine flow, particularly during periods of low water flow rates.

Abstract: Method of processing water including bath water and water employed in air treatment plants, which is conveyed in a circuit containing a contaminating point and a processing plant, the water exiting the contaminating point being contaminated water having a redox potential which is measurable and the method including, in the order recited, continuously measuring the redox potential of the contaminated water at the inlet of the processing plant; introducing into the contaminated water an auxiliary processing agent which is a mixture including a flocculating agent which promotes deposition of corpuscular pollutants and a halide which reduces ozone and disinfects the contaminated water as a function of the redox potential in such a way that the auxiliary processing agent is introduced in proportion to a drop in the redox potential; treating the water with ozone from an ozone generator in a spatial region defined within the processing plant and forming flocks including the corpuscular pollutants; and filtering the

Abstract: A system is disclosed for controlling the amount of treatment composition, e.g., cationic coagulant, to be introduced into an aqueous medium, e.g., a laundry waste water, having a content of non-solid fats, oils and/or grease (FOG) which is to be reduced. This system comprises a detector adapted to determine the electric charge value of a material comprising the aqueous medium having a FOG which is to be reduced and to provide a signal indicative of this electric charge value and an automatic processor provided with a relationship of the amount of treatment composition to be introduced into the aqueous medium to reduce the FOG of the aqueous medium to a given level as a function of the signal, and adapted to receive the signal and to provide a control signal to a source of treatment composition to control the amount of treatment composition introduced from the source of treatment composition into the aqueous medium.

Abstract: The concentration of amorphous silica in an aqueous solution is monitored to determine a concentration above which silica will precipitate. The precipitation concentration is data processed with a means for data processing by solving the Setchnow equation for aqueous solutions containing silica. The means for data processing generates a signal that, if need be, can be used to automatically adjust the parameters of the system to prevent silica precipitation or to carefully control the precipitation rate. An alternative embodiment provides a method for determining amorphous silica concentration, then data processing the solution to the Setchnow equation, generating a signal, and adjusting the parameters of the system. The apparatus and method of this invention are particularly useful in geothermal power plants.

Abstract: A process is provided for preparing preferred iron humate products. The preferred iron humate products provide iron and other nutrients and organic matter for vegetation. The preferred iron humate products are produced by using an iron salt coagulant that is relatively free of heavy metal contaminants and reacting the iron salt coagulant with naturally occurring humic substances such as those found in natural surface waters used in drinking water treatment facilities. According to the invention, iron is stoichiometrically reacted at a controlled pH with the humic and fulvic acid fractions in the water to precipitate an iron humate product precipitate. A preferred concentration of iron salt coagulants is used in order to minimize the formation of iron hydroxides which generally provide low iron availability to the plant. A more readily soluble iron humate complex is produced by the reacting and or blending of the iron humate residue with various nitrogen containing sources.

Abstract: A process and system for continuously recovering industrial waste water characterized as divergent hydro-lipophilic waste streams for industrial reuses to enhance water conservation and to reduce environmental pollution is disclosed. The process and system are especially suited for reclaiming animal and food processing discharge water having blood, fat, oil and grease contaminants in the water, for industrial reuse in evaporative condensers, hydraulic system cooling and equipment, non-food contact vehicles and plant or factory area wash-downs. The process can operate continuously for supplying water for such industrial uses, but also includes an automatic shut down if the incoming influent to be treated is too turbid. The process includes chemical pH adjustment, separation of fat, oil and grease (FOG) from the influent and particulate removal in polishing filters. Sensors are used to monitor the pH and component internal water pressures throughout.

Abstract: A device for detecting and monitoring the charge condition of finely divided solid charged particles in a fluid-flow is so devised as to accept the continuous and full volumetric flow of the fluid and to automatically and repeatedly sample and measure the charge condition. The full flow is accommodated without restriction in a passageway which intersects a bore wherein a streaming current detector (SCD), located below the passageway, is caused to cyclically sample and measure the charged-particle content of the flow; and at a passageway location downstream from the point point of cyclical sampling a head-creating formation assures that the fluid level will be raised to maintain a filled condition of the sampling bore. The device is further illustratively disclosed in use in a fluid-treatment system, wherein the SCD produces a signal to control flocculant added to the full flow of the fluid.

Abstract: A method for treating and resolving a phosphorus containing oily waste emulsion is described. The treatment uses an emulsion destabilizing cationic polymer of low molecular weight in combination with filter aids to form a coacervate slurry. The coacervate slurry can be optionally treated with either high molecular weight anionic or cationic coagulents, or combination thereof. The suspended solids formed by the above treatments are removed from the slurries and wasted or discarded or incinerated. The remaining liquids may be recycled, reused, or treated as effluent meeting environmental standards.

Abstract: The optimum antifoulant concentration and cleaning interval for reverse osmosis membranes is determined by providing samples of a liquid to be purified in a reverse osmosis system, the samples having a range of antifoulant concentrations added. The zeta potential for each sample is measured, and the amount of antifoulant that provides the lowest (most negative) zeta potential is selected as the preferred antifoulant concentration. A cleaning frequency sample of the liquid to be purified with the preferred antifoulant concentration is prepared and passed across a cleaning frequency membrane that passes dissolved matter in the permeate but does not pass colloidal material. The rate of change in flow of the permeate of the cleaning frequency sample is measured as a function of time, and the cleaning frequency of the cleaning frequency sample is determined.

Abstract: Optimum amounts of demulsifiers for breaking oil-in-water emulsions with low salt contents and high surfactant contents are determined by measuring the streaming potential in the emulsion to be broken.

Abstract: A method of treating sewage sludge is provided, in which the sludge is mixed with an alkaline material in such a way as to provide intimate surface contact that enables the alkaline material to permeate even small particles of the sludge, and to deliver the resultant product in a granular, scatterable form. The sludge and alkaline material are delivered to a mixing chamber and are confronted therein with a screw type mixer having generally helical flighting carried by a shaft, with the mixer being rotatably driven in generally horizontal arrangement to convey the mixture toward an outlet, with the mixture that is being mixed being maintained at a level in the mixer such that a spiral rolling action is imparted to the sludge and alkaline additive by the flighting engaging particles of sludge and rolling those particles up over the rotating shaft of the screw mixer.

Abstract: An apparatus for coagulating treatment which is capable of controlling the amount of addition of a coagulant to the optimum level thereby minimizing the water content of the dehydrated cake comprises coagulant adding devices (6), (7), and (8) for causing the coagulant to be added in a variable amount to a liquid subjected to the coagulating treatment, a heat transfer detecting meter (12) disposed so as to contact the liquid to which the coagulant is to be added, the liquid to which the coagulant has been added, or the filtrate from the liquid to which the coagulant has been added and adapted to detect a feeble change in the physical property of the liquid in the form of a change in voltage, and a control device (16) for controlling the amount of addition of the coagulant in the coagulant adding device (8) so that the value of detection of the heat transfer detecting meter (12) is minimized or kept within a desired range.

Abstract: Concentrations of cobalt and copper of electrolysis solution for electrowinning of zinc can be measured any time during electrowinning operation by continuously sampling the solution, diluting it, adding coloring reagent to the flow of the solution and spectrophotometrically analyzing the solution.The cobalt and copper as deleterious impurities can be removed continuously and automatically by measuring their concentrations by the above method and adding precipitation reagents for them in an amount calculated by a microcomputer on the basis of said analysis.

Abstract: The application relates to a process for removing nobler metal ions than iron, especially copper ions, from acidic process and waste waters by reduction under an inert gas atmosphere with carbonyl iron powders which have previously been subjected to a thermal treatment with hydrogen to remove nitrides and carbides. This process results in residual metal ion content <0.5 ppm and thus complete removal of the metal ions to be reduced.

Abstract: A method of detecting the initial concentration of a water-treatment chemical present in a diluted aqueous system, by (1) incorporating into the aqueous system, a mixture including a known amount of the active ingredient and a known amount of an ultra-violet sensitive compound having the formula (I): ##STR1## wherein halogen is chlorine or bromine; X is ##STR2## and a and b, independently are 0 or 1; M is hydrogen or an alkaline metal ion; and (2) detecting the concentration of the compound of formula I, by exposing to ultra-violet light a sample of the aqueous system so treated.

Abstract: A system is disclosed for controlling the amount of treatment composition, e.g., cationic coagulant, to be introduced into an aqueous medium, e.g., a laundry waste water, having a content of fats, oils and/or grease (FOG) which is to be reduced. This system comprises a plurality of detectors each of which is adapted to determine a parameter, other than the FOG level, of a material comprising the components of the aqueous medium and to provide a determined signal indicative of the determined parameter; and an automatic processor provided with a relationship of the amount of treatment composition to be introduced into the aqueous medium to reduce the FOG of the aqueous medium to a given level as a function of the plurality of determined signals, and adapted to receive the plurality of determined signals and to provide a control signal to a source of treatment composition to control the amount of treatment composition introduced from the source of treatment composition into the aqueous medium.

Abstract: Simplified single cell fluid flow apparatus for flotation removal of suspended impurities and liquids are provided wherein the method and apparatus are directed to an induced gas liquid coalescer for flotation separation of suspended impurities. The apparatus provides for a separation vessel which can be fabricated to withstand internal pressure requirements experienced in flotation separation devices wherein the apparatus induces maximum gas volumes consistent with optimum mass transfer of gas medium to suspended impurities in the liquid while controlling intercell or vessel chamber turbulence. Such maximum gas induction achieved without turbulence is through the use of microscopic gas bubbles. Such microscopic gas bubbles provide massive surface area with which the suspended impurities adhere and allows for various apparatus utilization.

Abstract: An on-line monitoring/control method for a separation process used to remove solids from a carrier liquid, wherein a portion of an influent stream containing both the carrier liquid and solids is diverted through a tube after addition of a separation agent, causing slugs of solids to form in the tube which are carried through the tube by clarified carrier liquid in plug flow, and wherein the clarity of the clarified carrier liquid is used to monitor or control the separation process.

Abstract: A beltpress controller performs on-line measurements of output sludge cake thickness. A controller takes a product of the measured cake thickness with belt speed, moisture content and belt width to determine a rate of dry solid output per unit time. The calculated rate is compared with a desired rate and the sludge flow rate is adjusted by adjusting the speed of a sludge feed pump to obtain the desired dry solid output rate. In systems which mix polymer with the sludge to increase the dewatering efficiency, the sizing of a mixing orifice through which the sludge and polymer is provided is adjusted to maintain a substantially constant mixing energy. This prevents errors in the streaming current detector which measures the amount of excess polymer in the filtrate and the controller adjusts the speed of a polymer dosing pump accordingly.

Abstract: Sedimentation in an inherently colloidally stable mixture comprising a suspension of solids in a liquid is controlled by a five-step process. In the first step a mathematical model representing a relationship between certain parameters, namely area product, viscosity and a parameter related to zeta-potential, is created. In the second step, zones in the model in which there is undesirably high viscosity are identified, In the thrid step, a model sedimentation path which skirts the high viscosity zones is superimposed on the model. In the fourth step, the actual mixture under consideration is monitored during a sedimentation process to obtain actual measured values of any or all of the critical parameters. In the final step, the parameters are adjusted as necessary to fit actual measured values to values on the model sedimentation path.

Abstract: A simplified single cell fluid flow apparatus for flotation removal of suspended impurities and liquids are provided wherein the method and apparatus are directed to an induced gas liquid coalescer for flotation separation of suspended impurities. The apparatus provides for a separation vessel which can be fabricated to withstand internal pressure requirements experienced in flotation separation devices wherein the apparatus induces maximum gas volumes consistent with optimum mass transfer of gas medium to suspended impurities in the liquid while controlling intercell or vessel chamber turbulence. Such maximum gas induction achieved without turbulence is through the use of microscopic gas bubbles. Such microscopic gas bubbles provide massive surface area with which the suspended impurities adhere and allows for apparatus utilization which is smaller and more compact for comparative treatment volumes.

Abstract: A process and apparatus useful for decanting suspensions at temperatures at and above the atmospheric boiling point of the liquid of the suspension are disclosed.

Abstract: To improve the dewaterability of sludge, which is dewatered in a dewatering device, in particular a plate filter press, a polymeric filter aid is added to the sludge. Since the flocs require a certain ripening time to form, a part stream of the unfiltered sludge is to be taken off according to the invention at the point opposite the feed and recycled into the main stream. The recycled flocs serve as flocculation nuclei. A further advantage of the sludge recycle is that the floc structure and/or size can then be scanned in the recycled part stream. The representative measured results are utilized for changing parameters which determine the dewaterability.

Abstract: The content of halo-organic pollutants in water is lowered to residual AOX values below 1 mg/l, preferably below 0.1 mg/l by adjusting the Fe.sup.2+ comtent of the water to 20 to 1000 mg/l, adding a precipitated or pyrogenic silicic acid, converting 20 to 1000 mg of the Fe.sup.2+ into Fe.sup.3+ by adding in an oxidation agent, preferably hydrogen peroxide, and separating the iron (III) hydroxy complexes formed and the silicic acid, which contain the halo-organic pollutants in an adsorbed state, at pH 5-10. The method can be controlled in a simple manner as regards the addition of Fe.sup.2+ and oxidation agent via the Fe.sup.2+ /Fe.sup.3+ redox potential.

Abstract: In a flotation system, the generated quantity of foam is determined and, independent thereof, process parameters which directly or indirectly affect the generated foam quantity are reduced in their quantity depending on foam quantity. This is brought about by reduction of specific substance flows and also such substance flows that circulate in a flotation system. Production waters used for dilution are partly replaced by fresh water. This precludes an excessive amount of generated foam from causing difficulties in the operation of a flotation system.

Abstract: Waste water treatment for the removal of heavy metals is optimized by continuously removing and filtering a sample flow of treated waste water subject to pH level control to determine the presence of remaining metals in solution to be precipitated. Filtering of the sample removes metals precipitated by pH level control. Optimized pH level control can cause precipitation of most non-chelated and/or non-complexed metals, so that controlled feeding of a precipitating agent, preferably a calcium dithiocarbamate, to the treated waste water is effectively determined by only those metals remaining in solution, which are typically either chelated and/or complexed heavy metals. The filtered sample is injected with a diluted solution of the precipitating agent, and then a turbidity meter is used to determine the degree of turbidity of the injected clear sample. The resulting degree of turbidity corresponds to the level of precipitation caused by injection of the diluted precipitating agent.

Abstract: A method of treating lake water to remove suspended solids and to precipitate and inactivate phosphorus comprises adding aluminum hydroxide sulfate to the water in a concentration such that the pH of the water is maintained at a level of greater than 6.0 and precipitation of suspended solids and precipitation and inactivation of phosphorus occurs. This invention is advantageous in that it provides a method of removing suspended solids as well as precipitating and inactivating phosphorus in water while simultaneously preventing the solublizing of toxic amounts of aluminum into the water with subsequent detrimental effects to aquatic life.

Abstract: During conditioning of a suspension to be dewatered through incorporation of flocculant, the optimum dewaterability depends on the amount of added flocculant and on the mixing energy expended. According to the invention, the sludge flocs present or formed in the suspension after incorporation of the flocculant are determined metrologically, and the amount of flocculant and/or the mixing energy expended and/or the location of flocculant addition is controlled as a function of the floc number, size and/or structure.

Abstract: An apparatus for extracting liquid from a sludge/conditioning agent mixture which comprises a first endless belt (10) of filter material; a second endless belt (12) of filter material; and rollers (20, 21, 22, 23, 24, 25, 26, 27, 13, 14, 15) for the belts (10, 12). That part of the belt (10) between the rollers (20, 23) is defined as a gravity de-watering zone; the part of the belts (10, 12) between the rollers (21, 13, 14, 15) is defined as a pressure de-watering zone. Filtrate is collected in a tray (17); liquid is collected in a tray (35). Monitoring means monitors a characteristic of the filtrate and the liquid to enable a rate of change in the characteristic of the filtrate/liquid to be determined. The apparatus functions at its optimum at a loading rate for the mixture which is just less than that which causes extrusion of the liquid in the pressure de-watering zone.

Abstract: A control system having opto-electric detectors responsive to different solids concentrations and character of the solids of a slurry, the output of the detectors controlling the addition of a flocculants to the slurry to optimize coagulation of the materials in the slurry. The detectors having outputs sensing different slurry conditions with the detector outputs being processed to control the addition of different flocculants to the cell.

Abstract: A system and method for removing heavy metals, such as hexavalent chromium from water. The system comprises at least two reactor containers for independently mixing chemicals with water. The system further comprises a flocculator and a clarifier whereby each container can separately treat water therein and separately transfer the treated water to the flocculator such that water treated in batches at the containers can be treated in a relatively independent manner with relatively constant results. The method of chemically treating the water in the containers includes decreasing the pH value, adding a reducing agent and then increasing the pH value in preparation for precipitating the heavy metals in the clarifier.

Abstract: A chemical mixture for treating spent dryfilm stripper and developer solutions by mixing the spent solutions with a solution of aluminum sulfate and borax in controlled amounts causing a surface absorption reaction which results in a slurry of a non-sticky, benign precipitate in a supernatant liquid. The supernatant liquid contains the dissolved heavy metals. The non-sticky precipitate does not interfere with the ph measurement which indicates when the reaction is complete, and the benign precipitate can be filtered out for disposal.

Abstract: Waste water treatment for the removal of heavy metals is optimized by continuously removing and filtering a sample flow of treated waste water subject to pH level control to determine the presence of remaining metals in solution to be precipitated. Filtering of the sample removes metals precipitated by pH level control. Optimized pH level control can cause precipitation of most non-chelated and/or non-complexed metals, so that controlled feeding of a precipitating agent to the treated waste water is effectively determined by only those metals remaining in solution, which are typically either chelated and/or complexed heavy metals. The filtered sample is injected with a diluted solution of the precipitating agent, and then a turbidity meter is used to determine the degree of turbidity of the injected clear sample. The resulting degree of turbidity corresponds to the level of precipitation caused by injection of the diluted precipitating agent.

Abstract: The invention involves a method for making uniformly sized particles from solid compounds. First, a suitable solid compound is dissolved in a suitable solvent. Then, a precipitating liquid is infused, precipitating non-aggregated particles with substantially uniform mean diameter. The particles are then separated from the solvent. Depending on the solid compound and the desired particle size, the parameters of temperature, ratio of non-solvent to solvent, infusion rate, stir rate, and volume can be varied according to the invention. The precipitating liquid may be aqueous or non-aqueous, depending upon the relative solubility of the compound and the desired suspending vehicle.

Abstract: A method for monitoring and/or controlling a liquid/solid separation process is described. The method utilizes photodetectors to view the surface of the composition being dewatered, and correlate the corresponding signals from the photodetectors to dryness values.This is a continuation of application Ser. No. 122,976, filed Nov. 19, 1987 now abandoned.

Abstract: Continuous monitor to determine effective performance of a flocculant used to dewater a sludge stream, in which a voltage waveform of water clarity, generated by a sensor opposed to a light beam transmitted across the stream, is digitized by a comparator; the comparator is insensitive to sludge flow rate.

Abstract: A process for demulsifying oil/water emulsions using an organic demulsifier which is added in the optimum amount by means of a controlling device for the metered addition, wherein the demulsification reaction is carried out at a temperature of from 60.degree. C. to 90.degree. C. with mixing.

Abstract: Precipitation (conversion) of dissolved heavy metals in waste effluents is achieved with the addition and mixing of a solution of sodium polythiocarbonate with a solution containing dissolved heavy metals. The solution of sodium polythiocarbonate has been pH buffered to a pH of 12.5 or less in the manufacturing process. Precipitation of the dissolved heavy metals with the buffered sodium polythiocarbonate is complete by the formation of a stable, unleachable [as defined in 40 CFR 190.01, Part 261 Appendix II (Code of Federal Regulations)], extremely insoluble metallic polythiocarbonate particle.

Abstract: Asphaltenes and/or wax and/or water are removed from crude oil by contacting the crude oil with an organic solvent to dissolve the crude oil and precipitate asphaltenes and/or wax and separate the oil and water. Solvent is then separated from the deasphalted and/or dewaxed and/or dehydrated crude oil.Removing asphaltenes, wax and/or water reduces the viscosity of the crude oil and it can then be transported, e.g. by pumping through a pipeline, with less expenditure of energy.

Abstract: Specific new polyurea-modified polyetherurethanes and their uses as breakers for water-in-oil emulsions, in particular as breakers for water-in-oil emulsions.

Abstract: The flow of waste water sludge flocculant to a dewatering system is regulated by a surface proximity sensor located downstream of the flocculant addition point. Depth, variability and continuity of a partially drained sludge mat are evaluated by a depth sensor signal processor/analyzer. Signal characteristics representative of an optimally flocculated sludge mat are referenced by the processor/analyzer to establish high and low control set-point values. A variable speed flocculant supply pump or flow control valve is adjusted in response to an operational signal from the depth sensor which exceeds the set-point range.

Abstract: Method for dewatering sewage sludge with the aid of organic polymeric flocculating agents (polyelectrolytes) made preferably by emulsion polymerization. To obtain optimum dewatering results, a substantial amount of the aqueous phase of the sludge is removed by decantation after flocculant addition prior to the dewatering treatment proper. The flocculated and thickened sludge may then be dewatered much more quickly with the dewatering behavior improved additionally by causing a reactivating flocculation to take place on the delivery side of the sludge feed pump. The Figures show a preferred embodiment of the inventive sludge dewatering system using a recessed plate press.

Abstract: A method of treating spent dryfilm stripper and developer solutions by mixing the spent solutions with a solution of aluminum sulfate and borax in controlled amounts causing a reaction which results in a slurry of a non-sticky, benign precipitate in a supernatant liquid. The supernatant liquid contains the dissolved heavy metals. The non-sticky precipitate does not interfere with the ph measurement which indicates when the reaction is complete, and the benign precipitate can be fillered out for disposal.

Abstract: Apparatus for controlling the coagulant dosage rate includes a charge sensor located adjacent a coagulant pump for measuring the net electrical charge on coagulated water before water treatment and a turbidity meter for measuring the effluent turbidity after water treatment. A programmable controller responds to the output signal of the charge sensor to continuously adjust the dosage rate to maintain a set point of charge value in the coagulated water corresponding to a desired effluent turbidity. To maintain calibration of the charge sensor, the controller is also responsive to the output signal of the turbidity meter to adjust the charge value set point as required so that the it corresponds to a preselected effluent turbidity.

Abstract: A method for using alkali for recovering amine used in a process for breaking emulsions and sludges. The amine has an inverse critical solution temperature with water. The process breaks a sludge into a water component containing residual amine and oil component if oil is present in the original sludge, and a solid matter component. The present invention uses alkali to minimize the amount of amine lost in the water component and in the solid matter component.

Abstract: The invention involves a method for making uniformly sized particles from water-insoluble drugs or other organic compounds. First, a suitable solid organic compound is dissolved in an organic solvent, and the solution can be diluted with a non-solvent. Then, an aqueous precipitating liquid is infused, precipitating non-aggregated particles with substantially uniform mean diameter. The particles are then separated from the organic solvent. Depending on the organic compound and the desired particle size, the parameters of temperature, ratio of non-solvent to organic solvent, infusion rate, stir rate, and volume can be varied according to the invention.

Abstract: In a filtration apparatus in which a flocculant is added to promote flocculation, efficient use of the flocculant is ensured by measuring an operational parameter of the apparatus dependent on the degree of flocculation, and adjusting the amount of flocculant being added to the minimum that causes maximum flocculation. As the operational parameter, measurement can be made of the depth of a pool of the material at the lower end of an upwardly inclined filter belt, or of the resistance to movement of a part of the apparatus e.g. the torque required to rotate a filter drum.

Abstract: An improved apparatus and process for feeding hypochlorite solution from a source of the solution to a device for removing impurities from water in a water treatment system is disclosed. The improvement comprises a first means for continuously measuring the oxidation/reduction potential of the effluent water of the device, and a second means operatively connected to the first means and the pump means continuously controlling the feed-rate of the pump means in response to the measured oxidation/reduction potential of the effluent water, thereby maintaining a predetermined oxidation/reduction potential in the effluent water of the device.