Abstract: A method for treating waste water which contains organic and inorganic compounds, particularly waste water from the synthesis of epichlorohydrins, in which the waste water is subjected toa) thermal-alkaline treatment,b) biological treatment, andc) optionally to chemical-oxidative treatment.

Abstract: The invention provides a method for removing sulphur compounds from water by anaerobic reduction of the sulphur compounds to sulphide, followed by a partial oxidation of the sulphide to elementary sulphur. The anaerobic reduction is carried out at elevated temperature, either continuously at a temperature of 45.degree.-70.degree. C., or periodically at a temperature of 55.degree.-100.degree. C. If the reduction is carried out periodically, a single rise in temperature for a few hours to several days over a period of 3-6 months can suffice. The method is particularly applicable to the removal of sulphate, sulphite and thiosulphate.

Abstract: The present invention relates to a process for the production of hydrogen comprising treating in an anaerobic condition a substrate such as waste water including organic matter using sludge compost, whereby stable hydrogen generation at a higher efficiency for a longer period of time is attained together with the treatment of waste water.

Abstract: A vehicle refueling station has a water treatment system for the vehicle washing installation which utilizes mechanical flotation and an aerobic treatment of the flotage to minimize sewer discharge. The gas from the anaerobic treatment is used to fuel a thermal electric converter which can also be fueled by vapors from the fueling operation. The thermal energy can be used to heat the water for car washing or for space heating purposes. The electrical energy can drive the electrical equipment at the refueling station.

Abstract: A composition and process for the degradation of fibrous materials is provided. More particularly, a composition comprising cellulase, sodium bicarbonate and citric acid, wherein the combination of sodium bicarbonate and citric acid unexpectedly increases the cellulase activity and thus improves the breakdown of toilet tissue in waste holding tanks, is set forth. The composition of the present invention may also include other additives known to those skilled in the art.

Abstract: A pure bacterial culture, designated herein as M91-3, has been isolated which rapidly degrades certain s-triazines, particularly halogenated s-triazines. The M91-3 degrades s-triazines, particularly atrazine, beyond the point of ring cleavage, leading to complete mineralization of the atrazine. The ability of M91-3 to completely degrade atrazine appears to be unique among bacteria. The M91-3 is capable of degrading s-triazine in solution and in presence of soil or sediment. The invention also relates to a method for degrading s-triazines, particularly atrazine.

Abstract: An in situ method of cleaning soil and/or water contaminated with a contaminant comprising one or more compounds selected from the group consisting of metal compounds, sulfur compounds and cyanide compounds comprises breaking up contaminated soil, admixing soil with water and a biodegradable detergent in a proportion effective to obtain an aqueous slurry where the soil, any contaminant and the detergent interact to form contaminant-detergent formations, allowing the slurry to stand under conditions effective to permit any contaminant-detergent formations to rise in the aqueous slurry, separating the contaminant-detergent formations from the aqueous slurry now comprising partially decontaminated soil and water, separating the soil from the water, repeating the cleaning and separation steps until the soil has less contaminant than a predetermined value, typically a 80-90% decrease, admixing the soil having a lower contamination level with water and an activating agent for microorganisms capable of removing the

Abstract: A method for treatment and disposal of propellant wastewaters, soil washwaters or groundwaters having dissolved perchlorate salts is described, which comprises adding to the contaminated water in an anaerobic reactor a mixed bacterial culture containing a specific bacterium, HAP1, which uses perchlorate as its terminal electron acceptor and thus reduces the perchlorate ion to chloride in the water; maintaining the proper nutrient and environmental conditions for HAP1 to optimally reduce perchlorate in the water and discharging effluent wastewater from the anaerobic reactor to an aerobic reactor and maintaining proper nutrient and environmental conditions for the optimal conversion of soluble organics to carbon dioxide and sludge and reduction of BOD, COD, ammonia and odor in the effluent water.

Abstract: A method for aerobically treating water-containing organic wastes is provided. This process may be conducted in a closed reactor with suitable controls to prevent any adverse environmental impact, and involves mixing the wastes with an inert and non-friable bulking agent comprising a substantial component having a density less than water in the presence of an active biomass. An oxygen-containing gas is passed through the reaction mixture to assist in the removal of excess (free) water from the wastes to form a wetted high solids content reaction mixture containing the waste solids mixed in a bed of bulking agent. Effective aerobic reaction conditions are employed to convert the wastes to a treated waste.

Abstract: A method is provided for bioremediating aged PCBs such as Aroclor 1260 in aquatic sediments under anerobic conditions by stimulating the dechlorination of the aged PCBs through addition of brominated or iodinated biphenyls or through the addition of a microbial inoculum from another location in addition to brominated or iodinated biphenyls.

Abstract: A method for aerobically treating a low solids water-containing oily sludge which comprises combining said sludge with a biologically inert, non-friable bulking agent characterized by having a substantial component with a density less than water to form a mixture, passing an oxygen-containing gas through said mixture to separate excess water and form a high solids content reaction mixture, reacting said high solids content reaction mixture in the presence of an aerobic biomass under effective aerobic conditions to form a treated sludge and an active biomass-coated bulking agent component having a density less than water in said high solids content reaction mixture, separating said biomass-coated bulking agent component from said treated sludge, and recovering said treated sludge from said reaction mixture has been provided.

Abstract: A system for the treatment of nitrate-containing wastewater from home or commercial, not municipal, sources is described in which the wastewater is contacted underground by denitrifying bacteria introduced to the treatment zone periodically; the treatment zone being maintained at or above the temperature at which the bacteria are active on a year-round basis by the ground temperature.

Abstract: An apparatus for determining transport characteristics across membranes and tissue sections comprises a plurality of cell blocks, where each cell block includes a pair of half-cells which hold the membrane or tissure section therebetween. A circulation path is provided in each half-cell block for exposing a fluid to one side of the membrane or tissue section. The cell blocks are maintained linearly within a base unit including a front plate and a back plate. The front and back plates are heated to maintain the cell blocks at a desired temperature.

Abstract: A temperature monitoring method and apparatus for monitoring the temperature within a mass of organic matter moved through a composting vessel. An elongated, stationary probe extends through the vessel from one end toward another end thereof. A plurality of temperature measuring devices are mounted along the probe. The probe may extend through a compaction ram and be provided with a sleeve for accommodating movement of the ram relative to the probe. A decoupling device provides for decoupling of the probe from a mounting base and an extraction device permits the probe to be extracted from the vessel for replacement thereof. The probe provides a method of monitoring temperature in the mass and a method of composting by monitoring temperature in the mass and regulating the temperature of the mass in response thereto.

Abstract: A method and apparatus are disclosed for dehalogenating and further biodegrading organic compounds, including halogenated organic compounds, present in an aqueous mixture, the mixture comprising the waste effluent produced in a continuous high flow rate by an industrial plant such as a bleach pulp or paper mill using chlorine and chlorine compounds. The aqueous mixture is passed through at least one combination of a first oxygen-enriched liquid zone and a second zone containing a mixed population of methylotrophic and heterotrophic microorganisms supported on a substrate bed. A first gas including oxygen is flowed through the first zone and second gas consisting substantially of a low-molecular-weight alkane is flowed through the second zone as the aqueous mixture passes through the first and second zones.

Abstract: The invention relates to a method and apparatus for treating waste material mass in a reactor comprising gas distribution members (2, 22), heating members (4, 23) and mixing members (6, 25) for the waste material mass, as well as a waste mass feed member (9, 31) and discharge opening (11, 34). According to the invention, the decomposition of the waste mass is intensified by heating the mass by means of the heating members (4, 23) connected to the gas distribution members (2, 22), by conducting gas onto the surfaces of the heating members (4, 23).

Abstract: A method is for operating a boiler to heat a bioreactor with gases produced from the bioreactor, while supplying excessive hot water to outside of a system. In the method, the boiler is operated to turn on and off depending upon temperature of a hot water tank when a level of a gas holder is higher than an intermediate level H.sub.1. Hot water is unconditionally supplied to the outside of the system when the level of the gas holder is higher than a high level H.sub.2, and hot water is supplied to the outside when temperature of the hot water tank is higher than an intermediate temperature L.sub.1 and the level of the gas holder is between the high level H.sub.2 and the intermediate level H.sub.1. The supply of the hot water is stopped when the level of the gas holder is less than the intermediate level H.sub.1.

Abstract: Addition of alkaline proteolytic enzymes derived from Bacillis licheniformis in the anaerobic stage of bacterial digestion processes to improve the settling properties of the bacterial biomass.

Abstract: The process for the disinfection of sewage sludge prior to introducing same into an anaerobic sewage sludge processing step involving the recovery of methane gas by heating the sewage sludge in a preceding disinfection step at from 50.degree. C. to 70.degree. C., and preferably at from 55.degree. C. to 65.degree. C., for a period of from 1 to 72 hours, and preferably of from 12 to 36 hours, while throughly mixing the sewage sludge with an oxygen-containing gas is carried out by using, as the oxygen-containing gas, a mixture comprising from 10 to 70% by volume of fresh air and 30 to 90% by volume of vent gas from the disinfection step, the oxygen contents of the gas mixture being maintained within the range of from 5 to 15% by volume, and preferably of from 7 to 12% by volume.

Abstract: An improved anaerobic fermentation process and apparatus for converting an influent liquid containing suspended organic matter to effluent gas and liquid products are provided. The influent liquid is introduced into and maintained in an anaerobic fermentation reactor containing anaerobic microorganisms at a temperature and a first pressure and for a time sufficient to form a gas containing methane and to form a liquid containing dissolved gas and suspended bacterial cell mass particles. The liquid is introduced into and maintained in a flotation vessel at a temperature, at a second pressure and for a time whereby gas dissolved in the liquid is liberated forming solution gas bubbles which rise and cause the suspended bacterial cell mass particles to be floated to the surface of the liquid. The floated bacterial cell mass particles are withdrawn from the surface of the liquid and from the flotation zone and recycled to the fermentation zone.

Abstract: An anaerobic process for the digestion of organic wastes, and novel anaerobic digester. In digestion of the organic wastes in the presence of anaerobic microorganisms, at anaerobic conditions, the carbon:nitrogen and nitrogen:phosphorus ratios of the digestion are adjusted to optimize the rate of anaerobic digestion, generally only about 12 to 72 hours, or less, being required to produce a stabilized low solids sludge and clean liquid effluent. The anaerobic digester is designed to facilitate this process, and is transportable from site to site.

Abstract: The invention relates to a method and apparatus for the reduction in the quantity of low activity organic wastes from nuclear power plants. This is accomplished using anaerobic fermentation in a bioreactor. The waste from the nuclear power plant is subjected to a pretreatment such as comminution and suspension, hydrolysis and/or physical dispersion, such as by a irradiation, heat treatment or the equivalent. The pretreated waste is subjected to anaerobic decomposition in a bioreactor, the anaerobic decomposition taking place in two stages, namely an acid stage and a methane stage. The gases produced in the decomposition process are conducted from the methane stage to a gas burning stage and the undecomposed waste is removed, concentrated and packed in barrels or the like for storage.

Abstract: A method and apparatus for an anaerobic process to reduce caustic requirements and to facilitate dissolution of organic acid having limited solubility by combining effluent from an anaerobic reactor having dissolved carbon dioxide with fresh feed containing the organic acid and stripping the carbon dioxide from the mixture to raise the pH.

Abstract: A closed water purification and recycle system processes domestic wastewater to produce potable water for cooking, drinking and dishwashing and water suitable for general household use, such as washing clothes and personal hygiene. The system consists of septic tanks, a biological sand filter, an ultrafilter, a disinfection unit, pumps, valves, water quality and quantity sensors to monitor and control the process. The system also includes an incinerator toilet to eliminate the need for toilet flush water. Water for cooking, drinking and dishwashing is produced by a still using some of the recycled water for feed. The quality of the recycled water is monitored to assure the product water is suitable for the intended uses. Water thus produced is stored until reused. The system will be automatically shut down if the final product water quality does not meet specifications.

Abstract: A non-mixed vertical tower anaerobic digester and anaerobic digestion process provides passive concentration of biodegradable feed solids and microorganisms in an upper portion of a continuous digester volume and effluent withdrawal from the middle to bottom portion of the digester, resulting in increased solids retention times, reduced hydraulic retention times, and enhanced bioconversion efficiency. In addition, due to passive concentration of solids, the non-mixed anaerobic digester accommodates high solids loadings and provides separation of microbial phases within the continuous digester volume to achieve substantially complete bioconversion of biodegradable feedstock components.

Abstract: The ammonia concentration present in waste water is reduced by treating the waste water with a suspended growth microbial system such as an activated sludge containing organisms of the genus Nitrosomonas and organisms of the genus Nitrobacter, but in which the microbial activity of Nitrobacter is effectively inhibited. The process includes a step of treating the microbial system under conditions effecting inhibition of the Nitrobacter but substantially unaffecting the growth and metabolic characteristics of the Nitrosomonas, and subjecting the ammonia containing waste water to the so treated microbial system for a hydraulic retention time which is less than the recovery time of the inhibited Nitrobacter. As a result, the retrograde step of nitrite-nitrate conversion in the overall denitrification process also is reduced or eliminated, with consequent energy and cost savings.

Abstract: A high rate reactor for the treatment of biosludge has been designed which combines the processes of landfarming, sand bed dewatering, and forced aeration composting. The reactor is essentially a sand bed overlying a drainage system housed in an inflatable, pressurized building.The high rate reactor can effectively treat biosludge through dewatering and biodegradation. Volume reduction, stabilization, and solidification are achieved at improved rates over conventional practices. The reactor operates independent of climate and is a closed system minimizing environmental monitoring.

Abstract: The bioconverter includes a collecting vessel having a plurality of stirring shafts rotatably mounted therein, each of which is driven by a separate electric motor. Adjacent shafts operate in opposite directions and stirring arms are oriented relative to each shaft moving the carrier mixture within the vessel which is in close proximity to a shaft in opposite directions along adjacent shafts. A moisture sensing device is adapted to be located below the level of the carrier mixture within the vessel for sensing the percentage moisture content of the mixture and waste material added thereto. A first fan is provided for exhausting the air from the vessel and a second fan is provided for moving the air over the surface of the mixture within the vessel. A first heating coil is located on the bottom of the vessel for heating the mixture within the vessel, and a second heating coil is provided adjacent the second fan for heating the air which is blown over the upper surface of the mixture within the vessel.

Abstract: A process for removing immunosuppressive substances from the blood serum of cancer patients comprises contacting the serum at a temperature below room temperature and preferably not greater than 5.degree. C., with Protein A of S. aureus immobilized on a substrate. Conducting the immunoabsorption at low temperature reduces the amount of anaphylatoxins produced in the process and thereby reduces the side effects of immunoperfusion treatment. An apparatus for low-temperature immunoperfusion treatment comprises a chamber for containing the immunoabsorbent, inlet and outlet tubes connected to the chamber, and a cooling jacket surrounding the chamber and at least a portion of the inlet tube.

Abstract: An anaerobic apparatus for treating wastewater is disclosed. The treating apparatus comprises a reactor housing a media having a plurality of surfaces for receiving bacteria. The wastewater that is to be treated, is introduced into the bottom of the reactor and forced up over the surfaces of the media, whereby the bacteria on the surfaces of and in the voids of the media consume the organic materials in the wastewater by an anaerobic digestion process to produce methane and a biological sludge. The biological sludge is collected and stored in a bottom storage portion of the reactor, whereby further digestion occurs to condense the mass of such sludge. A first conduit array is disposed above the media for withdrawing the treated wastewater. A second conduit array is disposed in communication with the storage portion for withdrawing biological sludge from the reactor.

Abstract: A method for improving the waste treatment of industrial bakery plant effluent by taking clarified effluent which has been subjected to pH changes to form sludge in a primary clarifier, removing said effluent from the initial sludge in the clarifier, and circulating it after sludge separation therefrom into a series of three underground tanks where a solution of activated anaerobic bacteria is metered. The residence time, for the effluent and bacteria in said tanks is 48 to 72 hours at a temperature of 28.degree. C. to 48.degree. C. Thereafter, the treated effluent is recirculated once again to a lower clarifier which feeds any sludge formed into a sludge concentration tank, while the aqueous effluent remaining is further processed in a sand filter, an ozonator, and a reverse osmosis unit to achieve a BOD level of below 150 (mg/l) and a COD level of below 80 (mg/l).

Abstract: An industrial waste anaerobic digestion process takes place in a digester having separate sections within the digester, in which the acid forming and gas forming phases of the digestion process can occur separately under conditions optimized for each phase. A rotating biological contactor is provided in each section for increasing the liquid/gas interface to facilitate the anaerobic reaction. A series of partitions is provided in each section to create zones in which the waste concentration is extremely high and on which the biota can react at maximal reaction rates. The CO.sub.2 produced in the acid forming phase is used in both acid and gas forming sections to mix and achieve pH adjustment, and the methane can be used in the gas forming sections for mixing. A thermophilic chamber in the center of the tank is surrounded by the mesophyllic chamber to minimize and utilize conductive heat loss.

Abstract: A method is disclosed for the biological aerobic purification of waste waters wherein a temperature from 30.degree. to 60.degree. C. is maintained in a first process stage and a temperature from 20.degree. to 40.degree. C. is maintained in a second process stage, with the temperature in the first process stage always being higher than the temperature in the second process stage and wherein a part of the activated sludge of the second process stage, after being seperated, is returned to the first process stage. The process provides a high decomposition output and produces an activated sludge which exhibits good sedimentation behavior.

Abstract: Non-organic substances are separated from household garbage and the organic substances are fed in proportioned manner into a mixing tank (5) and converted into slurry by adding liquid. The slurry is crushed for homogenization purposes in a crushing means (10, 11) and passed into a closed holding container (13). It is then fed over a heat exchanger (15) and heated to 55.degree. to 60.degree. C. The slurry passes into a plurality of reaction vessels (16) in which the methane gas and carbon dioxide are produced. In a separating plant (22), the mixture of gaseous products is broken down into its components and some of the methane gas is recycled by bubbling it through both the holding tank and the reaction tank, the remainder being stored in gasholders (23). The organic substances are degraded much more rapidly through increasing the degradation temperature and as a result constructional expenditure can be reduced.

Abstract: A method for environmentally upgrading waste water containing formates, cyanides and ammonia is disclosed. Formates and cyanides are biodegraded by aerobic bacteria immobilized on the disks of a rotating disk contactor. Ammonia is air stripped.The present method eliminates the steam stripping stage of conventional processes as well as the lime addition and precipitation stages.

Abstract: A wastewater treatment system and process utilizing a trickling filter with a rotary distributor extending thereover for the distribution of wastewater over the filtering medium. A sealed insulating dome overlays the filter to provide a closed environment. An underdrain system extends underneath the filtering medium covering the floor of the filter and includes perforated sections into which the applied wastewater flows. The perforated sections extend into an underdrain gallery which collects the applied wastewater to be recycled by the pump through the distributor or expended out of the filter. Controllable air recirculation system for selectively moving air under the dome through the filtering medium includes a blower in communication with the gallery which directs air through the gallery from under the dome, through discharge conduits and into the filtering medium. The direction of air flow is reversible and the introduction of atmospheric air is provided after passing through a controllable heater.

Abstract: This invention relates to a process for the biological purification of phosphate-containing wastewater wherein the wastewater is gas-treated, i.e. aerated, in an oxygenation tank in the presence of activated sludge for degrading organic hydrocarbon compounds and absorption of phosphate by microorganisms present in the activated sludge. The wastewater-activated sludge mixture is then withdrawn from the oxygenated tank and divided, in a post clarification stage, into purified, essentially phosphate-free water and phosphate-containing sludge. The phosphate-containing sludge is recycled, at least in part, into the oxygenation tank. A partial stream of wastewater-activated sludge mixture is branched off from the oxygenation tank, and/or recycle sludge is branched off as a partial stream from the post clarification stage, and the mixture is subjected to flotation treatment for thickening. A thus-obtained, low-phosphate flotage, i.e. subnatant liquor, is discharged from the flotation unit.

Abstract: Waste liquors containing high concentration of phenol and waste liquors containing methanol and formaldehyde in addition to phenol can economically be treated by a microorganism of geneus Aureobasidium to prevent water-pollution.

Abstract: A method and apparatus for operating a biological sewage purification plant wherein the water to be treated is aerated in a tank containing bacteria by means of a rotating impeller or the like, characterized in that a heating medium, preferably steam, is fed onto the surface of the water to maintain it at the optimum temperature for facilitating decomposition by bacteria without excessive heating and resultant destruction of the bacteria.

Abstract: Process for removing biorefractory compounds from contaminated water (e.g., oil shale retort waste-water) by contacting same with fragmented raw oil shale. Biorefractory removal is enhanced by preactivating the oil shale with at least one member of the group of carboxylic, acids, alcohols, aldehydes, ketones, ethers, amines, amides, sulfoxides, mixed ether-esters and nitriles. Further purification is obtained by stripping, followed by biodegradation and removal of the cells.

Abstract: In the operation of a recycling anaerobic filter for treating aqueous waste streams, the rate of production of methane is measured continually at frequent intervals and the COD feed rate is varied to maintain a predetermined, timed, relationship between that varied feed rate and the measured methane production rate.

Abstract: Purification of liquid agricultural wastes, such as, in particular, liquid anure, by means of an algae/bacteria mixture culture and a subsequent rotifer culture in a separate stage. The pH-value of the algae/bacteria mixture culture is controlled, especially by the waste water charging thereof, in such a way that a multiplication of rotifers in this stage is inhibited or precluded. The algae/bacteria mixture culture preferably occurs in shallow open air ponds for a period of time which depends upon the temperature and can amount to three to six days at a mean temperature of approximately 18.degree. C. The hold time of the algae/bacteria suspension which is in the rotifer container and is adjusted to a pH of 6 to 8 can range from two to four days at a temperature of approximately 20.degree. C. A waste water treatment plant or system for the foregoing includes at least one algae/bacteria mixture culture reservoir and at least one rotifer reactor.

Abstract: Composition for stimulation of aerobic bacteria in sewage or in soil from combination of B vitamins and an agent derived from digestion of milch cow excrement; and method of treating sewage or soil to stimulate the growth of aerobic bacteria to improve the condition of sewage for disposal or availability of soil nutrients for plant growth by addition of the composition to sewage or soil.

Abstract: A method for purifying wastewater of biodegradable organics by converting the organics to methane and carbon dioxide gases is disclosed, characterized by the use of an anaerobic attached film expanded bed reactor for the reaction process. Dilute organic waste material is initially seeded with a heterogeneous anaerobic bacteria population including a methane-producing bacteria. The seeded organic waste material is introduced into the bottom of the expanded bed reactor which includes a particulate support media coated with a polysaccharide film. A low-velocity upward flow of the organic waste material is established through the bed during which the attached bacterial film reacts with the organic material to produce methane and carbon dioxide gases, purified water, and a small amount of residual effluent material. The residual effluent material is filtered by the film as it flows upwardly through the reactor bed.

Abstract: The invention relates to a microbial process for the degradation of cyanuric acid in waste water containing cyanuric acid. The essential feature of the process is that a fungus of the Sporothrix genus, particularly a fungus of the Sporothrix schenkii variety is used for degrading the cyanuric acid. According to a variant of the process, it is possible to degrade, in addition to cyanuric acid, also any ammeline and ammelide present by using, besides a fungus of the Sporothrix genus, a second microorganism which is compatible with the fungus and which effects degradation of ammeline and ammelide to cyanuric acid. Waste water such as that accumulating in the commercial production of triazine herbicides can be purified by the process according to the invention.

Abstract: Organic wastes, such as animal manure, are fed into an elongated digester tank at one end thereof in slurry form. The slurry slowly moves to the other end of the tank for subsequent disposal. During the residence time in the tank decomposition of the waste occurs yielding methane gas and carbon dioxide. A cover over the digester collects the gas generated. A heat exchange arrangement causes transverse stirring of the slurry as it passes through the tank enhancing the decomposition process. Scum suppressors on the surface of the slurry prevent interference with the formation and release of the methane gas. The settling of solids is controlled by the use of gas jets disposed along the bottom of the tank.

Abstract: An on-site system in which means for treating domestic sewage generated within a building located thereon are totally integrated with means for modifying space temperatures and for heating water for sanitary and other purposes therein to form a matrix of interrelated and interdependent functions acting together to deliver only non-polluting products to the environment and to achieve maximal energy conservation.

Abstract: The disclosed invention is a continuous bioconverter or dry closet and method capable of aerobically and bacteriologically converting human and other organic wastes to principally carbon dioxide and water vapor. The closet comprises a collecting vessel containing a medium suitable for supporting aerobic decomposition. In accordance with the invention, the decomposition is a substantially total conversion of organic wastes to gases. In a preferred embodiment in the closet are two parallel shafts, each supporting a rotationally mounted pair of opposing auger-type blades (see FIGS. 1, 2 and 3) which provide a most efficient stirring action, resulting in a complete and continuous aeration (oxidation) of the aerobic bacteria in the chemically reactive organic mixture.

Abstract: In the disclosed method, organic waste material of a water content of at least about 50% and a solid content of at least about 15% is biologically digested into compost. The organic waste material contains a flora of different species of microorganisms having different oxygen consumption requirements and different metabolism. The organic waste material is introduced into an aerating reactor with top inlet and bottom discharge so as to form an air permeable material column in the reactor. Air, which may be enriched with oxygen, is blown through the column in an upward direction without mechanical agitation of the column. Since the flora of microorganism species present in the material has different oxygen consumption requirements and different metabolism, the air flow is controlled in such a way that the microorganisms can settle at distinct levels within the reactor space where the environmental conditions are most favorable.