Abstract: A method and apparatus for removing selenate from waste water through the use of selenate respiring microorganisms under substantially anoxic conditions is described. The method includes a first zone for removing nitrate by assimilation into biomass. The first zone is maintained under aerobic conditions and is separated from a second zone where selenate is respired to elemental selenium by selenate respiring microorganisms under anoxic conditions. Biomass produced in the first zone may be processed to provide nutrients and electron acceptors for the maintenance of selenate respiring microorganisms when selenate becomes growth limiting. An optional sulfate reduction zone is provided in the method and apparatus where hydrogen sulfide is produced. The hydrogen sulfide so produced is circulated to the second zone and may be used to reduce residual selenite to elemental selenium.

Abstract: An installation for the filtration and cleansing of liquids, notably water, of the type having a loop for the circulation of the water to be treated, including at least one tangential filtration membrane, comprising a new tangential membrane filtration installation, with ozone injection, enabling the surface, internal and chemical clogging of the membrane to be restricted. The installation includes means for the addition of an oxidizing gas to the liquid to be treated, in the loop upstream of the membrane, so as to form microbubbles of said gas with a size such that they create turbulence in the liquid at the membrane and this turbulence, combined with the phenomenon of oxidation, restricts the clogging of said membrane and leads to an improvement in the flow rate and in the physical/chemical qualities of the filtrate. If necessary, it includes means for the injecting of chemical reagents and/or absorbents into the filtration loop.

Abstract: In a process for biodegrading under highly alkaline conditions organics in a waste stream derived from a Bayer processing system for producing aluminum oxides,i) the waste stream being typical of oxalate waste streams resulting from alkaline treatment of bauxite, the oxalate waste streams being rich in oxalates, formates, acetates, benzoates and sodium ions and having a pH in excess of 8,ii) treating the highly alkaline waste stream to neutralize and thereby lower pH and to reduce sodium ion concentration prior to introducing the waste stream into a bioreactor,iii) biodegrading the oxalates in the bioreactor by use of Pseudomonas genus microorganisms, andiv) discharging at least a portion of the biodegraded waste stream, the improvement being characterized by:a) introducing the highly alkaline waste stream rich in sodium ions to the bioreactor to avoid the treatment of step ii),b) biodegrading the organics in the waste stream with the Pseudomonas genus microorganisms characterized by ATCC 53883 deposited micr

Abstract: Waste sludges containing up to 35% weight percent hydrocarbon contaminants and up to 50% weight percent inorganic materials are treated to induce acclimation of indigenous microbes present therein, the acclimated indigenous microbes thereby releasing extra-cellular enzymes capable of catalyzing hydrolysis of at least the hydrocarbon contaminants in the waste sludges. This step is pursued until a substantial increase of biological activity takes place in the waste sludges. Biological activity is allowed to continue at an increased rate until the hydrocarbon contaminants are substantially biodegraded.

Abstract: A biological process is described involving the conversion of SO.sub.2 to H.sub.2 S using sulfate reducing bacteria in co-culture with facultatively anaerobic heterotrophs under anaerobic conditions in a maintenance medium which includes a substrate fermentable by the facultatively anaerobic heterotrophs to produce an end product which acts as the carbon and energy source for the sulfate reducing bacteria. Glucose and sewage sludge are the two fermentable substrates described. The process is described as being used in conjunction with a process for removing SO.sub.2 from a flue gas and then converting the SO.sub.2 to H.sub.2 S. The H.sub.2 S may be reacted with some remaining SO.sub.2 in a Claus reactor to produce elemental sulfur or the H.sub.2 S may be used as a reducing gas to regenerate the sorbent being used to remove the SO.sub.2 from the flue gas.

Abstract: A method for treating soil contaminated by organic compounds wherein an ozone containing gas is treated with acid to increase the stability of the ozone in the soil environment and the treated ozone applied to the contaminated soil to decompose the organic compounds. The soil may be treated in situ or may be removed for treatment and refilled.

Abstract: A method is provided in accordance with this invention for treating wastewater in a tank having comminute, mix and settle sections. The method comprises receiving wastewater in the comminute section, comminuting solids in the wastewater, mixing the wastewater with air in the mix section, mixing the wastewater without further addition of air, mixing the wastewater with air again, directing wastewater to the settle section, separating solids from the wastewater, returning the solids to the mix section, and discharging the effluent from the tank. In another aspect, this invention relates to an improved apparatus for carrying out the method of this invention.

Abstract: A complete mix activated sludge basin is operated as a Sequence Continuous Reactor by cyclically aerating the mixed liquor to form an aerobic cycle at selected high dissolved oxygen levels, during which nitrification takes place, and cyclically mixing the liquor without aerating to form anoxic cycles at selected low dissolved oxygen levels, during which denitrification takes place. Field adjustments can be made by the operator in the dissolved oxygen levels and in the duration of the aerobic and anoxic cycles, whereby ammonia removal, nitrification, and denitrification can continue to be done efficiently during both summer and winter temperature conditions, during conditions varying from warm to cold inlet wastewater temperatures, during extreme variations in food supply, and during pronounced variations in biomass concentration and activity.

Abstract: A floating aquatic plant water treatment system (31) utilizes a serpentine channel (36) defined by dividing walls (34). Floating plants (72) are distributed across the water surface by a floating grid structure (32). The grid structure (32) is preassembled into Z-fold bundles (88) which are towed onto the water and unfolded. The treatment system uses sprayers (62) to control growth conditions. Porous baffles (46) are placed along portions of the channel (36) to provide intimate contact with a larger portion of the water while allowing free flow.

Abstract: A waste liquid treatment system (10) includes an aeration chamber (10A) and a settling chamber (13). An aerator (11) is disposed within the aeration chamber (10A). A conduit (12) delivers liquid from the aeration chamber (10A) to the settling chamber (13). A gas pocket (P) is provided in the aerating chamber (10A), with at least a portion of the gas pocket (P) being situated beneath the liquid level line (L.sub.13) of the settling chamber (13). Conduits (18 and 19) are provided for delivering liquid from the settling chamber (13) to the aeration chamber (10A). The conduits (18 and 19) have respective outlets (24, 26) which empty into the gas pocket (P) at an elevation below the settling chamber liquid level line (L.sub.13). In one embodiment, a gas pocket (P) is provided in the interior of a tubular component (23) of the aerator (11). In another embodiment, a gas pocket (P') is provided beneath a concave hood (32) which traps gas bubbles (30) introduced into an aeration chamber (110A).

Abstract: A filter device for use in the treatment of water to render it potable, which is of particular value in emergency situations, comprises exo-polysaccharide producing, gram-negative bacteria supported upon a water-permeable material which is non-toxic to microorganisms and to human beings, is resistant to temperatures within the range from -15.degree. C. to +65.degree. C., and is not readily biodegradable. The device may be freeze-dried to enable it to be stored until it is required for use and may then be reactivated by the addition of water. It may be used as the surface layer in a slow-sand filter.

Abstract: A process for purifying water, which comprises passing water contaminated with halogenated compounds through one or more fixed or fluidized bed reactors which are connected in series and packed with an adsorbent material which is inoculated with one or more microorganisms. The process results in almost complete elimination of the halogenated hydrocarbons.

Abstract: A biological denitrification is provided in which ammonium ion is used as an electron donor in the denitrification. The process may advantageously be used under conditions of high ammonium ion concentrations in waste water or to remove ammonium ion from manure, soil or surface water. Microorganisms are described which may be used in these processes.

Abstract: A sewage treatment pond has an inlet for introduction of sewage into the pond and an outlet for removal of sewage from the pond. A first baffle extends from the surface of the pond to the bottom of the pond and between the inlet and the outlet. The first baffle has an opening located a first distance from the surface of the pond so that sewage can pass through the opening. A second baffle is located between the inlet and the outlet. The second baffle extends from the surface of the pond to the bottom of the pond. The second baffle has an opening located a second distance from the surface of the pond.

Abstract: The invention is a method for using periphyton to treat flowing water in a waterway. The periphyton reduces the quantity of undesirable chemicals polluting the water. Fish, in turn, control the density of periphyton by grazing on the periphyton and convert the undesirable chemicals associated with the periphyton into removable forms such as fish tissue or fish feces.

Abstract: An improvement in the biological method for treating wastewater is provided. The method is featured by adding to the reactor an amount of floating porous biomass carrier which can be mixed thoroughly with the wastewater to be treated. By the utilization of the carrier, the microorganisms can be retained in the reactor in a high concentration and the mass transfer can be adjusted so that various phases of microorganisms are provided within the reactor. The method is also characterized in that the reactor is operated under aerobic, anoxic and/or anaerobic conditions which are sequentially provided in an appropriate order depending on the type of pollutant to be treated. The method can remove organic substances, and nitrous and phosphorus materials effectively in a single reactor, and reduce the volume of the resultant sludge and the capital investment greatly as compared with the prior art methods.

Abstract: A method and apparatus is disclosed for oxidation of aqueous mixtures of organic material, including toxic material in the presence of inorganic materials, by reaction of said material with water and oxygen at supercritical conditions. Oxygen and the aqueous mixture are separately pressurized to greater than about 218 atmospheres, combined to form a reaction mixture and then directed through a tubular reactor having a substantially constant internal diameter. The velocity of the reaction mixture is sufficient to prevent settling of a substantial portion of solids initially present in the reaction mixture and of solids which form during passage through the reactor. The mixture is heated to temperature above about 374.degree. C. in the tubular reactor. A substantial portion of the organic material in the reaction mixture is oxidized in the tubular reactor to thereby form an effluent mixture.

Abstract: A BOD-containing wastewater also containing unacceptable levels of phosphorous, nitrogen or mixtures thereof is introduced into and mixed with recycled activated sludge in a first aeration zone including at least one partially submerged rotatable biological contactor under conditions whereby the overall dissolved oxygen content of the mixed liquor in the first aeration zone is about 0.7 to about 1.5 mg/l so as to cause microorganisms capable of storing phosphates under oxidizing conditions to release soluble phosphates into the mixed liquor, the mixed liquor from the first aeration zone is transferred to a subsequent aeration zone and aerated under conditions whereby the overall dissolved oxygen content of the mixed liquor is greater than about 1.

Abstract: This invention relates to a sewage sludge treatment system resulting in an oxygenated and/or ozonated treated sludge containing substantially no pathogens. The system includes apparatus and a process for mascerating raw sludge, adjusting the pH to about 2.5 to about 3, adjusting the solids content to about 2.5% to about 4%, adjusting the temperature, if necessary, to about 20.degree. C. to about 40.degree. C., mixing an oxygen-rich gas, such as oxygen and/or ozone with the sludge as the sludge is mixed or recirculated through a hyperbaric vessel and simultaneously injecting the oxygen-rich gas into a combination gas and sludge mixing and dispersing assembly in an upper portion of the hyperbaric vessel. Such injection causes mixing of the gas and sludge and dispersement of such mixture in a plurality of streams to atomize and oxygenate the sludge.

Abstract: A method is disclosed for detoxifying an aqueous waste solution containing cyanide. The method involves adding a source of silicon oxide to the cyanide containing aqueous waste solution in a concentration of 0.001 to 10 g silicon dioxide/liter aqueous waste solution, at an alkaline pH and a temperature of from 10.degree. to 100.degree. C. Hydrogen peroxide or another peroxygen compound is added in a sufficient quantity to convert the aqueous waste solution containing cyanide to an aqueous solution containing environmentally less toxic materials.