Abstract: A process for optimizing the rate of oxidation using halogen, e.g. chlorine donors to prevent the accumulation of undesirable chlorinated by-products. The feed rate of a chlorine donor is controlled for maintaining a desired ORP, the rate of oxidation is sufficient to prevent the accumulation of the undesirable by-products. Treatment removes the by-products from the water and surrounding air by maintaining continuous breakpoint halogenation conditions.

Abstract: This invention provides a process for the biotreatment of wastewater from pulping industries. Sulfides are removed by a number of strains of bacteria from the genus Thiobacillus or Thiobacillus denitrificans. COD and BOD are concurrently removed with the sulfides by an improved co-cultural blend comprising co-cultures of a number of strains of the Thiobacillus or Thiobacillus denitrificans bacteria with heterotrophs. At least approximately 20%, and preferably between approximately 40% and approximately 60%, of the improved co-cultural blend comprises the co-cultures of a number of strains of the Thiobacillus or Thiobacillus denitrificans bacteria with the heterotrophs. Acclimation of the heterotrophs to the species to be removed is accomplished with biological acclimation reactors which reduce mycell toxicity for the heterotrophs. To control pH of the heterotrophic reaction with inorganic and organic sulfides, magnesium oxide (MgO) is utilized along with caustic.

Abstract: In treatment of water by injection of ozone into the water for removal of harmful matters, odor matters, and color matters therein, either or both of a nonyl phenol and a cresol are added to the water to be treated. The nonyl phenol is added together with a lower alcohol or acetone to the water to be treated. The cresol is added together with a lower alcohol or acetone to the water to be treated. A p-nonyl phenol is added as the nonyl phenol for treatment. As the cresol for addition, a p-cresol is added. As the nonyl phenol for addition, a nonyl phenol is used such that two molecular weights of 220 and 107 are detected when measured by either or both of gas chromatography and mass spectrometry. By the above treatment, the decomposition reaction of ozone can be accelerated, and thereby it becomes possible to accelerate the oxidative decomposition reaction of organic matters, the amount of ozone required for the decomposition of harmful matters can be reduced with the decomposition time.

Abstract: The present invention is generally directed to a process and system for treating animal waste. More particularly, the present invention is directed to a process and system for treating animal waste effluent with ozone to decompose the organic material within and improve the odor of the animal waste. The process of the present invention also reduces biochemical oxygen demand, chemical oxygen demand, total bacterial content and coliform bacterial count of the animal waste. The process of this present invention comprises collecting an animal waste solution, containing a mixture of water and animal fecal material; contacting the waste solution with ozone in an amount sufficient to oxidize at least a portion of the organic material contained within; and feeding the ozone treated waste solution to a solids separating device prior to collecting the waste solution in a biobasin or, alternatively, recycling the ozone treated waste solution for use as a source of irrigation or flushwater.

Abstract: Hydrogen sulfide is removed from water by methods and apparatus that cause sufficient oxygen to be dissolved in the water for sufficient time at sufficient pressure to precipitate out solid elemental sulfur and other solid sulfur particles.

Abstract: A method and system for wastewater treatment is described and is particularly suitable for manure lagoons and pits. Specifically, an ozone gas is homogeneously distributed through an upper stratum of a contained liquid thereby creating an aerobic "cap", while still maintaining an anaerobic lower stratum. A perforated tube or plurality of tubes fixed within the upper stratum serves to distribute the ozone. Alternately, a buoyant vehicle propelled across the surface of the liquid may also serve to distribute the ozone and create the ozonated "cap". The vehicle provides an additional benefit of crust fragmentation and prevention thereby inhibiting and eliminating fly propagation, and hygienically improving lagoon or pit operation. In either embodiment, the ability to create an aerobic and anaerobic balance within the liquid facilitates a reduction in odor, a significant improvement of organic digestion and solids control, and a reduction in pathogens sometimes found in water recycled from the containment area.

Abstract: A process is disclosed for the removal of algae-associated odorant from fresh water by contacting such water with cyclodextrin and recovering the water so contacted.

Abstract: A method of reducing sulfide odors in wastewater collection and treatment systems. The method includes adding nitrate ions in the form of a controlled release composition and microbes to the wastewater effective to reduce hydrogen sulfide levels. The controlled release composition can be in the form of a water-in-oil emulsion. The microbes can be aerobic and facultative Bacillus species.

Abstract: A process for the biological treatment of a spent caustic solution containing sulphides is disclosed, wherein the solution is introduced into an aerobic reactor containing sulphide-oxidising bacteria, and the sulphides are partly converted to elemental sulphur and partly to sulphate by controlling the redox potential in the reactor at a value below -300 mV (against an Ag/AgCl reference electrode), or below -97 (against a H.sub.2 reference electrode). Also disclosed is process for the biological treatment of an aqueous solution containing sulphides and/or mercaptans in an aerobic reactor, wherein the solution is treated in the presence of bacteria of the new species Methylophaga sulfidovorans.

Abstract: A method for accelerating the treatment of chemical wastes, particularly recalcitrant wastes such as spent caustic, from the oil, gas, chemical, and petrochemical industries, in which normally slow physical mass transfer of different fluid phases, as well as other chemical reactions, are facilitated. The method involves mixing together the different fluid phases and delivering the mixture to a reaction vessel in the form of an aerosol and froth which provides a large surface area between the phases. The aerosol and froth mixture is maintained and replenished for a period of time sufficient to effect mass transfer and stripping of the contaminants to a selected level of completion. The method enables the provision of more environmentally acceptable wastes for disposal.

Abstract: Process for the photocatalytic purification of waste water contaminated by tetrahydrothiophene, applicable to the purification of condensation water collected along gas distribution lines for household and industrial use.

Abstract: The present invention relates to an improved method for treatment of feed water for swine to reduce odor and water pollution arising from lagoon slurry while at the same time improving live performance and carcass data. The inventive method comprises the steps of a) producing a gaseous mixture supply of ozone and oxygen gas from ambient air; b) effecting directing contact between said gaseous mixture derived from step (a) with a supply of water by means of a venturi injector device to produce a solution of said gaseous mixture and said supply of water; c) continuing said contact between said gaseous mixture and said water supply until the content of ozone in said water supply is within a range of from about 0.5 parts per million to about 10 parts per million, and the content of oxygen is about 80-97% saturation; and d) providing the resultant water supply from step (c) for use as feed water to swine.

Abstract: A method and composition are provided for controlling odor from waste products. The composition comprises a combination of chlorite salt and nitrate salt. The method includes the step of contacting the waste products or their surrounding airspace with the composition.

Abstract: The effluent gas stream from anaerobic waste water treatment digesters is treated to remove trace amounts of hydrogen sulfide and other contaminants. The chemical equation involved relies on the reaction of hydrogen sulfide with oxygen to form water plus elemental sulfur. The removal system includes a variable control line for adding air to the effluent gas stream; a filter for removing solids, entrained liquids and bacteria from the oxygen-enriched gas stream; a blower for directing the filtered gas stream into a potassium promoted activated carbon bed wherein the above chemical reaction takes place; and sensors for measuring the content of oxygen and hydrogen sulfide at the entrance and exit of the activated carbon bed. When the hydrogen sulfide content of the exiting gas stream exceeds a predetermined level, the amount of air added to the gas stream is increased until the predetermined level of hydrogen sulfide is achieved in the exiting gas stream.

Abstract: Owing to the concomitant storage, transport, material and handling problems and the unsatisfactory retarding of reinfection, the use of commercially available peracetic acid solutions with a high peracetic acid (PES) and acetic acid content for disinfecting large quantities of aqueous solutions, e.g. purification plant outlets, has been closely limited. It is possible to disinfect even large quantities of aqueous solutions economically and at the same time retard reinfection by using a peracetic acid solution containing 1.5 to 2.5 wt. % peracetic acid and 40 to 60 wt. % hydrogen peroxide and under 2 wt. % acetic acid as a disinfectant. The use of a peracetic acid solution with less than 1 wt. % acetic acid is preferred.

Abstract: Nuisance concentrations of hydrogen sulfide and other malodorous compounds are controlled in liquid and sludge waste systems by adding alkaline iron. The process removes immediate sulfide and suppresses the formation of further nuisance sulfide with a single application. As the sulfide and other malodors are being mitigated in this process, alkalinity is added to the waste as a reaction by-product, which acts to increase the waste pH, decreasing corrosivity and promoting biological treatability and purification of the waste.

Abstract: The present invention relates to a method of manufacturing filtering aids, coagulants or clarifying agents, and odor suppressants and a using a protein-polysaccharide complex composition as a filtering aid, coagulant or clarifying agent, and odor suppressant for in the processing of fluids including gases and liquids to absorb a variety of separable components.

Abstract: An ion-exchanged purified water having an odor substance generated from a double bed type purified water producing apparatus and a mix bed type purified water producing apparatus is flowed through a hydrogen type weak acid cation exchange resin to obtain an odor-free refined purified water. Moreover, an original water is passed through a single ion-exchange tower in which a mix resin layer of a regenerated mix bed type purified water producing portion is arranged at an upper portion and a hydrogen type strong acid cation exchange resin of a polisher portion is arranged at a lower portion, so that an odor substance in the ion-exchanged purified water generated from the mix bed type purified water producing portion is removed by the polisher portion and the odor-free purified water is obtained.

Abstract: A method is provided for improving the dewatering and odor reduction characteristics of a liquid wastewater sludge, sediment, or soils to ultimately form a dewatered solid residual that includes nutrition enhancement of a resultant material that is suitable for distribution and marketing, and for incorporation in a fertilizer blend. The material meets Class A pathogen reduction by achieving disinfecting conditions. The method includes the addition of selective acids and bases to the liquid sludge which forms insoluble precipitates, and enmeshes the solids in the sludge to form a granular product. The method's applicability includes municipal, agricultural, food processing, industrial liquid and semi-liquid sludges, sediments, and soils.

Abstract: The present invention relates to a process for the purification of a medium containing organic waste. The process according to the present invention is characterized in that the starting medium (or effluent) containing the organic waste is subjected to the following stages: (i) treatment with at least one oxidizing agent; (ii) treatment with at least one flocculating agent; (iii) treatment with at least one polyelectrolyte, and in that the effluent obtained on conclusion of all of these stages is subjected to a filtration stage (iv), whereby a filtration cake and a filtrate are obtained. The process according to the present invention is more particularly useful for the treatment of pig manure.

Abstract: There is provided in the present invention a small bore sewer system comprising a clarifier tank for receiving sewage, separating liquid and solid sewage and retaining the solid sewage; and a collection device connected to the clarifier tank for receiving the liquid sewage and carrying it to a sewage treatment plant. The system may further include pumping stations and gravel and sand odor filters.

Abstract: A water aerator (1) has a vertically oriented aerator tube (2) with a plurality of water-inlet apertures (3, 16) that preferably are downwardly slanted intermediate an air-inlet end and a water-outlet end of the aerator tube. The aerator tube is positioned linearly inside of a water-input sleeve (4) having a water-input aperture (5) that is proximate a top of the aerator tube. A bottom end of the water-input sleeve is sealed to a portion of the aerator tube that is vertically below the plurality of water-inlet apertures. A one-way air-inlet valve (7, 14) can be provided in an air-inlet conveyance (6) to the aerator tube to prevent possible excess input of water from escaping through the air-inlet conveyance. Pluralities of air-inlet conveyances and aerator tubes can be provided.

Abstract: Wastewater lagoons are treated with chlorine oxygen compounds to react with odorous sulfides and mercaptans emanating from the lagoon. A fine spray of an aqueous solution of the chlorine oxygen compound (HOCl, NaClO.sub.2, or NaOCL) is applied over the lagoon. The chlorine oxygen compounds react with the sulfides in the vapor zone above the lagoon, converting the odorous compounds to non-odorous compounds.

Abstract: A method of treating sludge to provide a stable product for use as a beneficial soil or fertilize for agricultural lands is disclosed which includes the steps of:(a) mixing sludge with at least one alkaline material in an amount sufficient to raise pH of the mixture to a level of at least 12 and to increase percent of solids in the mixture to at least 40% by weight, and such that odorant sludge organics and inorganics are bound to adsorbent particles of the alkaline material,(b) aerating and drying the mixture by agitation and heating to stabilize the mixture and increase the percent solids to at least 50% by weight, and(c) pasteurizing the dried mixture at a temperature at or above 52.degree. C.

Abstract: The method of treating wastewater or bioorganic sludges containing odor, animal viruses, pathogenic bacteria, and parasites to produce a bioactive but stabilized product that is useful as a soil substitute or as a fertilizer which can be applied directly to lands which consists essentially of the following steps: mixing said sludge with at least one alkaline material, wherein the amount of added material mixed with said sludge is sufficient to raise the pH of said mixture to pH 12, and raise the conductivity to disinfect and stabilize the sludge, and adding green waste at different process locations so that a biological action occurs converting the greenwaste into a soil-like granular product with improved odor over that of the treated municipal sludge alone or a composted greenwaste alone.

Abstract: A method for reducing and controlling the formation and release of acid gases and odors associated therewith, particularly from hydrogen sulfide, in sewerage or waste water, wherein magnesium hydroxide and/or magnesium oxide are added to the sewerage or waste water.

Abstract: A composition and a process for substantially reducing or removing sulfide from a sulfide-containing fluid are disclosed. The composition comprises, or is prepared by combining components comprising, a sulfide-containing fluid and a sulfide-scavenging amount of a sulfide scavenger selected from the group consisting of bromates, iodates, and combinations of two or more thereof. The process comprises contacting a sulfide-containing fluid with a sulfide-scavenging amount of a sulfide scavenger under a condition sufficient to substantially reduce the sulfide concentration in the fluid.

Abstract: A method of remediating methyl amine and/or methyl amine derivative odors in aqueous systems by contacting the methyl amine or methyl amine derivative with a compound having amide or imide functionality, such as a hydantoin composition, in the presence of hydrogen peroxide. The amide/imide composition is preferably a non-halogenated, singe-ring hydantoin that binds methyl amines to the amide or imide functional group of the hydantoin.

Abstract: A method and apparatus for treating nuisance odor streams is provided. One embodiment of the invention is directed to a method and apparatus in which deodorizing chemical agents are applied to an evaporative reaction pack situated within a gas chamber having an air stream running therethrough. The evaporative reaction pack provides a reaction zone within which the chemical agent is evaporated to facilitate a gas-gas or vapor phase interaction between the chemical agent and odoriferous compounds contained in the air stream. Another aspect of the present invention relates to a method and apparatus for batch processing of sewage treatment agents within a wet well to prevent the formation of undesired compounds. In one embodiment, a predetermined amount of chemical agent, sufficient for treating the amount of sewage that the well can hold, is added to an evacuated wet well in coordination with the pumping of sewage from the wet well.

Abstract: An apparatus for removing dissolved hydrogen sulfide from water including an atomizing tank defining an open end. A manifold is positioned adjacent the open end. The manifold defines an inlet channel having a first inlet port and a second inlet port. The first inlet port is in communication with aerated water containing dissolved hydrogen sulfide. An atomizing nozzle is in communication with the second inlet port for atomizing the water to cause the dissolved hydrogen sulfide to react with oxygen in the air to form sulfate in the atomizing tank. At least one filtering tank is in communication with the atomizing tank for filtering the sulfate from the water. The method of the present invention includes the steps of: (a) aerating water containing dissolved hydrogen sulfide with air at a predetermined pressure; and (b) atomizing the water to cause the dissolved hydrogen sulfide to react with oxygen in the air to form sulfate.

Abstract: A method for the treatment of waste water, which comprises treating waste water containing at least a sulfide-type malodorous substance, in the presence of a transition metal compound and hydrogen peroxide or a hydrogen peroxide-forming compound, wherein at least an iron family element compound and a vanadium family element compound are used as the transition metal compound.

Abstract: A method and apparatus for the treatment of sediment. The apparatus provides a plurality of injection sites for injecting a biochemical oxidant into the sediment. The oxidant is useful for oxidizing a bacterial growth inhibitor to a non-inhibiting form thus permitting bacterial growth and thus greater numbers for sediment detoxification.

Abstract: An improved method and apparatus for treating a gaseous medium polluted with volatile organic solvents to produce a purified gaseous medium and a separate methane-rich and combustible gas. The method involves wet-scrubbing the gaseous medium with a liquid stream in a countercurrent wet scrubber to produce a purified gaseous medium and a separate liquid stream loaded with the volatile organic solvents; channelling the liquid stream loaded with the volatile organic solvents to an anaerobic bioreactor consisting of a sealed vessel containing a biomass having methanogenic bacteria adapted to transform the volatile organic solvents into a methane-rich and combustible gas and a separate liquid stream output substantially free of the volatile organic solvents; recovering the methanerich and combustible gas by collecting the gas from the anaerobic bioreactor.

Abstract: The apparatus for waste water treatment has, in a tank, a contact circulation part in which Bincho charcoal is accommodated, a sprinkling circulation part which is disposed above the contact circulation part and in which black coal is accommodated, air lift piping for lifting treatment-object water from the contact circulation part to the sprinkling circulation part, a water-sprinkling tube for sprinkling the treatment-object water onto the sprinkling circulation part, an aquatic plant cultivation bed disposed between the contact circulation part and the sprinkling circulation part, and air-diffusing tubes for introducing malodorous gas. Small quantity of surfactants and colorants are adsorbed by the Bincho charcoal and the black coal and decomposed by microorganisms that have grown in the Bincho charcoal and the black coal. The microorganisms act to biologically decompose the malodorous gas.

Abstract: A scrubber apparatus and controller includes an outlet gas sensor, and a processor operatively connected to the outlet gas sensor and a treatment chemical supply pump for controlling a level of treatment chemical in scrubbing solution responsive to the sensed undesired constituent, such as hydrogen sulfide and/or other odorous gases associated with wastewater. Accordingly, the controller enhances reduction of the undesired constituent in the gas being treated and while conserving consumption of treatment chemical. To enhance the operating life of the outlet and inlet gas sensors, the processor preferably only periodically exposes the gas sensors to gas, and also periodically supplies purging air to the gas sensors. The controller preferably includes an environmentally resistant housing containing the processor means and the outlet gas sensor. In addition, the inlet gas sensor is also preferably included to provide feed forward control and also to provide a log of both inlet and outlet gas readings.

Abstract: A scrubber apparatus and controller include a gas sensor, and processor for controlling treatment of gas responsive to the sensed undesired constituent so as to enhance reduction of the undesired constituent. The processor further determines a sensor fault and may generate an alarm signal responsive to the sensor fault. The gas sensor is preferably an electrochemical cell comprising an electrolyte and a pair of electrodes associated with the electrolyte. A sensor fault may be determined based upon an impedance of the electrolyte and the pair of electrodes. In addition, the electrochemical cell may include a gas permeable membrane and a pair of electrodes on opposing sides of the membrane to permit determination of damage to the membrane based upon an impedance measurement using the pair of electrodes.

Abstract: A process for removing both color and odor from wastewater effluent that is contaminated from dye complexes, such as azo dye complexes, used for dyeing textiles to be various colors. The process requires treatment of the effluent with alkali metal permanganate, followed by treatment with hydrogen peroxide, followed by treatment a primary coagulant as a flocculation initiator (together with pH control so that the pH is basic), followed by treatment with a water soluble polymer, and followed by separating precipitated flocculated material from the effluent to obtain a clear effluent free of color and odor.

Abstract: A sewage purification method which includes a first step in which at least two kinds of flocculants are introduced in sewage for stirring and mixing therewith so as to float and settle inorganic and organic materials. The first step is sequentially repeated more than one time. Next, at least three kinds of flocculants are introduced into the supernatant obtained in the first step for stirring and mixing therewith so as to further float and settle remaining inorganic and organic materials. At least one of the first and second steps is sequentially repeated more than one time. In the above way, middle water, drinking water and super-pure water can be obtained from sewage. Purification of exhaust gas is also possible by introducing such exhaust gas in one of the above steps.

Abstract: Process for purifying gaseous or liquid effluents containing sulphur-containing derivatives (H.sub.2 S, alkyl mercaptans, SO.sub.2).This process comprises: (i) basification of the effluent to be treated at a pH >9 in the presence of a base of general formula M--OH, in which M represents an alkali metal, an alkaline-earth metal, an agent for condensation between the organic part of the compound of formula I below and the sulphur-containing derivative or a phase transfer agent and especially a quaternary ammonium or a ligand; (ii) placing of the product obtained in (i) in contact with a compound of general formula I: X--(CH.sub.2).sub.n --CO--R, in which: X represents: a halogen, a sulphonyl halide of formula X'--SO.sub.2 --R', in which X' represents a halogen and R' represents a C.sub.1 -C.sub.20 alkyl group or an optionally substituted aryl group, an OH group; R represents: a C.sub.1 -C.sub.

Abstract: The invention relates to a method for removing hydrogen sulphide (H.sub.2 S) from oil-containing water and equipment therefor. Oil-containing water and nitrate is conducted through a bioreactor to remove H.sub.2 S. Nitrate is added to the oil-containing water in a dose ratio (sulphide:nitrate) of 1:10 to 1:40. The retention time in the reactor tank is 10-60 minutes. After this treatment, purified water where >90% of the H.sub.2 S-amount is removed are taken out of the tank. The equipment for performing the method is based on a bioreactor having a large density of denitrifying bacteria. The reactor tank 1 is filled with carrying material providing large contact area. Even distribution of oil-containing water and nitrate over the carrying material which already may be covered by septic mud, forms an active sulphide oxidizing biofilm having a large surface. This biofilm is extremely effective for removing sulphide from oil-containing water.

Abstract: A low concentration (0.1 to 0.5 mM) of aluminum ions is added to an organic wastewater to selectively raise specific bacteria which can grow without producing unpleasant odors. The bacteria is used for treating the organic wastewater of high density without producing odors thus contributing to the minimum size of a wastewater treatment system. Then, increase of the aluminum ions to a high concentration (more than 4 mM) accelerates flocculation and precipitation of the bacteria for disposal. When a proper mineral is added to the wastewater, a lower concentration (more than 1 mM) of the aluminum ions can encourage the flocculation and precipitation of the bacteria and also, a resultant sludge will be reduced in amount for ease of maintenance.

Abstract: Dry, free flowing solids, suitable for handling, transportation and/or disposal are produced from messy biologically treated sludges. In the process, the sludge feed is pressurized and heated, then flashed, in order to vaporize a portion of the water; the residual liquid, containing the solids and sometimes heavy metals, is contacted with a chelating agent, if needed, and a flocculating agent over a brief reaction period in order to precipitate a concentrated solid precipitate; and the precipitate is separated from the residual liquid water.

Abstract: A method of removing noxious odors and preventing erosion within waste water headworks, said headworks including a headworks structure for waste water, an inlet line, an outlet line and a vent line; a method of removing noxious odors and preventing erosion within said headworks structure, comprising the step of introducing into a vapor space above the level of said waste water in said headworks structure, a low turbulence flow of ozonated air in sufficient volume of said ozonated air to form a blanket above said level of said waste water in said headworks structure and in an ozone concentration effective to prevent the formation of a biofilm, said introduction of ozonated air further being of a sufficient volume and ozone concentration to substantially react with malodorous gases present in said headworks structure without causing substantial erosion of said headworks structure by said ozonated air.

Abstract: A process for the catalytic deodorization of and reduction of the nitrogen content in liquid manure tank effluents comprises:(a) in a basic medium catalytically oxidizing mercaptans into disulphides while simultaneously forming salts of hydrogen sulphide,(b) catalytically post combusting ammonia and amines to form nitrogen oxide,(c) catalytically reducing nitrogen oxides in the presence of a gaseous stream containing ammonia and amines.

Abstract: A method of removing dissolved iron or sulfur from water comprising the steps of pumping water containing the dissolved impurities through a conduit. Air is added to the water and is thoroughly and intimately mixed with the water in a closed mixing container. The iron or sulfur is chemically reacted with the oxygen to form a filterable precipitate which is filtered from the water.

Abstract: A method of animal waste treatment which provides the introduction of a solid material in the animal waste, having the following characteristics; a solid geometric shape, a solid which floats in the animal waste, a solid which is biodegradable, a solid which includes at least resins with formaldehyde and ferrous sulfate.

Abstract: A limited amount of grey water is collected in a storage tank for use in flushing toilets. During use, the grey water in the storage tank is stirred to discharge small particulate solids with the grey water supplied to a toilet. The stirring also prevents the grey water from stratifying and preventing disinfectant from reaching stratified grey water which in the absence of disinfectant and stirring could become stagnant. The stirring action of the grey water also makes the system self cleaning.

Abstract: Malodorous/foul smelling paper mill effluents are deodorized by treating same with an effective deodorizing amount, e.g., from 0.01% to 5% by weight thereof, of an alkyl or polyoxyalkylene ester of undecylenic acid, for example methyl undecylenate or a polyoxyethylene undecylenate having 8 or 10 ethylene oxide recurring structural units.

Abstract: A method of removing noxious odors and preventing erosion within waste water enclosures is provided comprising the step of administering a flow of ozonated air into a vapor space above the level of the waste water in the enclosure, wherein the volume of the ozonated air and the concentration of ozone in the ozonated air are sufficient to prevent the formation of biofilm on the ceiling and walls of the enclosure. The method is intended to produce a blanket of non-turbulent, ozonated air directly above the surface of the waste water so that escaping undesirable chemicals, such as hydrogen sulfide, are caused to fully react with the ozone. The reaction with ozone minimize odors emanating from the enclosure and it deprives the bacteria forming the biofilm of the chemicals needed to sustain them. Residual, unreacted ozone also serves to eliminate the biofilm by directly reacting with the bacteria within the enclosure.

Abstract: Removal of dissolved hydrogen sulfide and a reduction in BOD is achieved by the addition of nitrate ions to waste systems in an amount sufficient to stimulate growth of bacteria which utilize dissolved hydrogen sulfide in their metabolism. Specifically, about 2.4 lbs. .Iadd.nitrate .Iaddend.oxygen per lb. of sulfide is required.