Abstract: Disclosed herein are systems and processes for treating a Waste Stream comprising biosolids, the Waste Stream provided at varying flow rates and solids concentrations so as to achieve an SOUR of 1.5 mg O2/g/hr or less and an ORP of at least +300 mV. The system includes a biosolids manipulation device to adjust the volume of suspended solids as a percent of the total volume of the Waste Stream to five (5) percent or less; a chemical oxidant feed device to dose the Waste Stream with an oxidant such as chlorine dioxide, ozone, or similar oxidant, and a treatment vessel associated with said chemical oxidant feed device through which said Waste Stream flows, wherein said chemical oxidant feed device and said treatment device are configured so as to achieve a dose rate between 25 and 200 parts per million of the Waste Stream and substantially complete mixing of the oxidant within 30 seconds of dose delivery in the treatment vessel.

Abstract: Disclosed is a bioreactor for treating sewage comprising an aerobic tank including a mixing cell for receiving sewage to be supplied from an inlet and mixing the sewage with activated sludge and an aerobic reactor tank in which the activated sludge adsorbs organic substance existing in the sewage; a backwashing cartridge filter for removing floc resulting from growth of the activated sludge adsorbing the organic substance; and an anaerobic tank for carrying out a denitrification process for denitrifying treated water flowed through the backwashing cartridge filter using anaerobic ammonium oxidation (anammox) bacteria wherein the backwashing cartridge filter allows the sewage discharged from the aerobic tank to pass through the cartridge filter and separates the floc and the treated water using difference in size between the floc contained in the sewage and pores in the cartridge filter, and wherein foreign matter adsorbed on the cartridge filter is easily removed by means of washing water to be injected into

Abstract: The present invention concerns a process for treating waters containing at least two different dissolved inorganic salts which do not precipitate and/or crystallize in the same conditions by precipitation and ballasted flocculation, in which the ballast is produced in situ.

Abstract: Increased control and efficiency over the wastewater purification can be achieved through creating conditions that allow selective prioritization of the digestive function of microorganisms in the activated sludge. The gas-dispersion return sludge is created using pure oxygen or oxygen containing trace amounts of ozone as a reactive gas, which is blended with return sludge to create a mixture of gas and liquid, which is passed through an atomizer or a cavitation pump to instantly render the reactive gas in the mixture to an ultra-fine bubble state. At least a portion of the ultra-fine bubbles dissolve within the gas-dispersion return sludge, activating the dormant microorganisms. Due to a complete or an almost complete absence of digestable organic material in the gas-dispersion return sludge, the microorganisms prioritize their digestive function, and when exposed to organic pollutants present in wastewater, digest the pollutants into water and carbon dioxide at an increased rate.

Abstract: A circulating moving bed biofilm method for biological purification of waste water in a continuous process includes receiving a pretreated waste water inlet stream in an anaerobic zone of a reactor wherein micro-organism culture exist on free flowing biofilm carriers, letting the waste water stream with the biofilm carriers into an aerobic zone aerating the waste water stream and carriers received from the anaerobic zone, at an end of the aerobic zone, transferring the biofilm carriers to the anaerobic zone without transfer of water, and discharging the water through an outlet to a sludge separation process.

Abstract: The present invention relates to an anaerobic reactor (10) for the treatment of industrial and other wastewaters at psychrophilic temperatures, the reactor comprising a mixing chamber (12) in which is located, during use, a granular sludge fluidized bed, the reactor further comprising a biofilm chamber (16) fed from the mixing chamber and housing a biofilm colonized pumice-based carrier material, and a separation chamber (18) in fluid communication with the biofilm chamber and in which treated effluent and biogas produced within the reactor are separated.

Abstract: The present invention provides a method for efficiently separating cesium ions in a short time from an aqueous solution with the number of human working steps being reduced as much as possible and recovering the cesium ions, and an apparatus therefor. Cesium ions in an aqueous solution are removed by preparing a cesium ion-containing magnetic particle in a cesium-containing aqueous solution and filtering or magnetically separating the magnetic particle.

Abstract: A method of treating wastewater includes removing BOD and ammonium from the wastewater. The wastewater is directed into a tank where it is mixed with mixed liquor or activated sludge from an activated sludge wastewater treatment system. The mixture of wastewater and mixed liquor or activated sludge forms a mixed liquor stream. The mixed liquor stream is directed to a ballasted flocculation system where suspended solids is removed from the wastewater. This produces a clarified effluent that is directed to a zeolite tank. Clarified wastewater from the ballasted flocculation system is directed into the zeolite tank and mixed with zeolite. Zeolite is effective to remove ammonium from the wastewater. Thus, the process as a whole is effective in removing suspended solids, soluble BOD as a result of mixing the mixed liquor or activated sludge with the wastewater, and ammonium.

Abstract: A process and system for treating wastewater is described. The invention degrades sludge produced by treatment of the wastewater to reduce or eliminate the need for sludge dewatering and disposal. The invention also reduces the amount of nutrient additives required to sustain the aerobic wastewater treatment process. In one embodiment the invention includes the steps of (a) providing an aerobic treatment system receiving a supply of the wastewater; (b) treating a supply of the sludge to rupture microbial cells present therein to produce treated sludge having an increased liquid:solid ratio and an increased degradation potential in comparison to untreated sludge; (c) conveying a supply of the treated sludge to the aerobic treatment system; and (d) substantially degrading the supply of treated sludge in the aerobic treatment system. The treated sludge may optionally be subjected to anaerobic digestion prior to delivery to the aerobic treatment system.

Abstract: An apparatus and method for selecting, retaining or bioaugmenting solids in an activated sludge process for improving wastewater treatment using screens. The screens can be used to separate and retain solids based on size, compressibility or shear resistance. The screens are used to separate and select slow growing organisms, faster settling organisms, or materials added to absorb, treat or remove constituents in the activated sludge process. A swapping screen arrangement provides another means of selecting various particles. The exposed shear rate or time, particle compression, or SRTs can be adjusted manually and/or automatically in response to detected readings from an instrument such as a spectrophotometer or other optical approaches to optimize selection of organisms.

Abstract: The wastewater treatment method includes, when raw water is subjected to an activated sludge treatment, performing a first sludge returning step: a step of returning sludge, which was previously aerated and stirred in a first excess sludge tank or sludge retention tank equipped with an aerator and a stirrer, to an treatment tank, a sequencing batch reactor or an anaerobic tank; an optional step of returning sludge, which was previously aerated and stirred in a second excess sludge tank or thickened sludge retention tank equipped with an aerator and a stirrer, to a treatment tank, a sequencing batch reactor or an anaerobic tank; and maintaining genus Bacillus bacteria in the treatment tank, the sequencing batch reactor or the anaerobic tank, to which the sludge has been returned, at 2.0×105 to 22.5×105 cfu/mL.

Abstract: Waste-treatment processes are enhanced through generation and introduction of specific biological populations customized to perform or favor specific tasks either during the main process, for the formation or precipitation of certain biological nutrients, or to accomplish solids formation reduction in a post-treatment process. These bacteria may be grown from specialized mixes of activated sludge and waste influent by exposing these materials to controlled environments (e.g., in an off-line treatment area). They may then be returned to the main process to perform certain tasks such as converting particulate cBOD into soluble cBOD for utilization, to reduce high solids yield organisms by supplementing the population characteristics with low yield organism characteristics, to provide biological nutrients or oxygenation assistance, to improve nitrification/denitrification efficiency, or to disfavor filamentous biology such as Norcardia sp.

Abstract: A method for treating waste-activated sludge comprises adding (1) a pozzolanic material to waste-activated sludge to form a mixture. The mixture is homogenized and aerated (2). The pozzolanic material reacts with the waste-activated sludge. The mixture is allowed to settle (3). A portion of the mixture is recirculated (4) from a downstream location to an upstream location. The recycled mixture includes pozzolanic material. Some embodiments provide advantages over existing wastewater treatment methods which may include: reduction or elimination of unpleasant odours, reduction of overall costs, conversion of waste into useful products, and/or reduction or elimination of discharged bacteria or other undesirable materials.

Abstract: Wastewaters are treated by an activated sludge process that includes combining wastewater with bacteria-laden sludge in an activated sludge tank to form a mixed liquor, separating the mixed liquor into a clear effluent and activated sludge stream, pretreating at least a portion of the activated sludge stream in a conditioning tank, transferring at least a portion of the activated sludge stream in the conditioning tank to an interchange bioreactor operating in batch or continuous flow mode, processing the activated sludge stream within the interchange bioreactor by selecting desired growth conditions to cultivate at least one type of bacteria in the activated sludge stream, and returning at least a portion of the activated sludge stream in the bioreactor to the activated sludge tank. The process may further include a sidestream reactor to remove phosphates from the activated sludge stream leaving the interchange bioreactor.

Abstract: A biological treatment method and device for organic wastewater, whereby the amount of minute organisms which reduce the amount of excess sludge and held within an activated sludge tank can be stabilized so that the treatment can be stabilized, are provided. Substrates for growing dispersed bacteria and/or dispersed bacteria are supplied to a sludge treatment tank 51 which reduces the sludge by the minute organisms, so that the minute organisms grow stably and reduce the sludge. Specifically, a first and a second biological treatment step are conducted respectively in a first activated sludge tank 21 and a second biological treatment tank 31. The sludge included in effluent which flows from the biological steps is separated in a sedimentation tank 41. The generated sludge obtained is supplied to the sludge treatment tank 51.

Abstract: The invention provides a side stream type membrane bioreactor process which does not cause an excessive fall in the MLSS concentration in a bioreactor, does not require any additional effluent treatment facility for discharging backwash effluent, and can further ensure the stability of the membrane filtration performance of a separation membrane. According to the invention, in a side stream type membrane bioreactor process, a backwash effluent containing foulants that are generated by backwashing a separation membrane is collected in a backwash effluent tank, and subjected to ozone treatment, and the resultant is returned to a bioreactor. By this ozone treatment, the foulants close to the membrane pore size of the separation membrane are made fine or are made into a state be easily taken into activated sludge flocs. Therefore, even when the treated effluent is returned to the bioreactor, the membrane filtration performance of the separation membrane is not deteriorated.

Abstract: Wastewater treatment system and process in which the influent is passed through a mixing chamber and then through a series of filters of progressively smaller size to separate the materials carrying the colonized bacteria from finer solids in the influent and separate the materials according to size. The materials from the filters are progressively reduced to a smaller size, the materials of smaller size are returned to the mixing chamber, and new influent is inoculated with the colonized bacteria carried by the materials returned to the mixing chamber.

Abstract: Already-treated sludge is fed back into incoming sewage, and is effective to supply nutrients needed for the microbiological breakdown of the sludge. The feedback sludge has a solids content of 10% or more, and has been sheared and heated to drive its viscosity down to 10,000 cP or less. In sludge done that way, nutrients are preserved and presented to the sewage to be treated in highly liquidised and solubilised form, whereby the nutrients are very bio-available to the microbes in the sewage. Large improvements in the elimination of biomass can result.

Abstract: Waste-treatment processes are enhanced through generation and introduction of specific biological populations customized to perform or favor specific tasks either during the main process, for the formation or precipitation of certain biological nutrients, or to accomplish solids formation reduction in a post-treatment process. These bacteria may be grown from specialized mixes of activated sludge and waste influent by exposing these materials to controlled environments (e.g., in an off-line treatment area). They may then be returned to the main process to perform certain tasks such as converting particulate cBOD into soluble cBOD for utilization, to reduce high solids yield organisms by supplementing the population characteristics with low yield organism characteristics, to provide biological nutrients or oxygenation assistance, to improve nitrification/denitrification efficiency, or to disfavor filamentous biology such as Norcardia sp.

Abstract: A method for removing inert solids from low-yield wastewater treatment processes. The method includes combining wastewater with bacteria-laden sludge in a mainstream reactor to form a mixed liquor, separating the mixed liquor into a clear effluent and activated sludge, returning a first portion of activated sludge to the mainstream reactor, treating a second portion of activated sludge in a sidestream bioreactor prior to returning the second portion of activated sludge to the mainstream reactor, and employing a screening device within the wastewater treatment process to remove inert solids.

Abstract: A system and method for the ozone treatment of wastewater is disclosed. The disclosed wastewater treatment system includes a high selectivity reactor coupled to an activated sludge treatment basin. The high selectivity reactor is adapted to receive a stream containing sludge diverted directly or indirectly from the activated sludge treatment basin. The disclosed wastewater treatment system and method is adapted to inject a chemical agent, such as ozone-enriched gas, into the diverted stream for treatment within the high selectivity reactor for purposes of sludge reduction, foam control, or bulking control. The treated stream is then returned to the activated sludge treatment basin.

Abstract: A method for the physical and biological treatment of an organic effluent, which is decomposed by microorganisms in a biological treatment zone, includes recovering a fraction of the biomass derived from the biological treatment, filling a compression reservoir with the biomass fraction, isolating the compression reservoir, and subjecting the filled compression reservoir to a very high pressure so to destroy or damage the microorganisms in the biomass fraction. Thereafter, the compression reservoir is returned to atmospheric pressure and the treated biomass fraction is reinjected into the biological treatment zone or into another biological treatment zone.

Abstract: A method for managing multivalent metal ion concentrations in low-yield wastewater treatment processes. The method includes combining wastewater containing BOD with bacteria-laden sludge in a mainstream reactor to form a mixed liquor, separating the mixed liquor into a clear effluent and an activated sludge stream, returning a first portion of the activated sludge stream to the mainstream reactor, processing a second portion of the activated sludge stream in a sidestream bioreactor, returning at least a portion of the activated sludge stream in the sidestream bioreactor to the mainstream reactor, and adding multivalent metal ions to at least one of the wastewater, the mixed liquor, the activated sludge stream and combinations thereof to reduce the generation of waste activated sludge.

Abstract: An efficient system and process for removing nitrogen from wastewater while enriching seed sludge in the mainstream treatment process. Bioaugmentation of seed autotrophic organisms facilitate the nitrification reactions by enhancing the rates of reaction advantageously within a smaller volume or within a shorter activated sludge solids retention time. Likewise, bioaugmentation of seed denitrification organisms will also enhance rate of reaction within a smaller volume or shorter activated sludge solids retention time. Separate treatment of high ammonia digester reject water is an efficient method to treat nitrogen in recycle streams as well as to enrich the seed nitrifying and denitrifying cultures.

Abstract: A system and method for the ozone treatment of wastewater is disclosed. The disclosed wastewater treatment system includes a high selectivity reactor coupled to an activated sludge treatment basin. The high selectivity reactor is adapted to receive a stream containing sludge diverted directly or indirectly from the activated sludge treatment basin. The disclosed wastewater treatment system and method is adapted to inject a chemical agent, such as ozone-enriched gas, into the diverted stream for treatment within the high selectivity reactor for purposes of sludge reduction, foam control, or bulking control. The treated stream is then returned to the activated sludge treatment basin.

Abstract: A method for managing multivalent metal ion concentrations in low-yield wastewater treatment processes. The method includes combining wastewater containing BOD with bacteria-laden sludge in a mainstream reactor to form a mixed liquor, separating the mixed liquor into a clear effluent and an activated sludge stream, returning a first portion of the activated sludge stream to the mainstream reactor, processing a second portion of the activated sludge stream in a sidestream bioreactor, returning at least a portion of the activated sludge stream in the sidestream bioreactor to the mainstream reactor, and adding multivalent metal ions to at least one of the wastewater, the mixed liquor, the activated sludge stream and combinations thereof to reduce the generation of waste activated sludge.

Abstract: A method and system for treating water or wastewater to remove both soluble BOD and suspended solids. The method entails a ballasted flocculation process where a flocculant and insoluble granular material is added to the water or wastewater to be treated causing solids in the water or wastewater to aggregate around the granular material to form ballasted floc particles. In a settling zone, ballasted floc particles form settled sludge and the settled sludge is separated from clarified effluent. At some point in the process, activated sludge, in the form of return activated sludge or mixed liquor, is mixed with the water or wastewater being subjected to the ballasted flocculation process. The addition of activated sludge enables the process to remove soluble BOD.

Abstract: A method and apparatus for building a lagoon based advanced treatment system or upgrading an existing lagoon system for advanced treatment of wastewater. The lagoon is provided with a baffle to create a complete mix zone in which an aeration system and bioconcentration modules are installed. Biological solids are concentrated in the modules and drop through their open bottoms where the solids are recirculated and mixed by the aeration system. Once a biomass equilibrium is reached in the complete mix zone, excess solids are passed into the rest of the lagoon for standard treatment there. The complete mix zone is operated as a low rate activated sludge process with a detention time much less than for the rest of the lagoon, maintaining sufficient heat and sludge aging to effect complete biological nitrification and/or denitrification.

Abstract: There is disclosed a method of recovering factor VIII/vWF-complex which is characterized in that factor VIII/vWF-complex from a protein solution is bound to a cation exchanger and is recovered by step-wise elution of factor VIII/vWF-complex, which particularly contains high-molecular vWF multimers, as well as a factor VIII/vWF-complex obtainable by means of cation exchange chromatography.

Abstract: An activated sludge process for the clarification of wastewater comprising introducing the wastewater into a reactor where microorganisms consume organic material in the wastewater to form a mixed liquor comprising water, the microorganisms and an activated sludge; separating clarified water from the mixed liquor by filtration through a microfiltration or ultrafiltration membrane; separating the activated sludge from the mixed liquor; adding to the activated sludge at least one high molecular weight water soluble polymer to form a mixture of water and coagulated and flocculated solids; dewatering the coagulated and flocculated solids to form a mixture of dewatered solids and filtrate water; and recycling the filtrate water into the mixed liquor and a method of controlling polymer dosage, preferably using fluorescence emission spectroscopy.

Abstract: According to this wastewater treatment apparatus, wastewater can be treated by novel action by a foaming tank 7 in comparison with a treatment method solely using a biological treatment tank 1 constituting an aeration tank. That is, wastewater can be treated by action achieved by combining (1) action solely of a biological treatment tank 1 and (2) action of a foaming tank 7. Specific action in this foaming tank 7 includes supply of dissolved oxygen to wastewater and oxidation by bubbled air (micro air) under a favorable condition with a shallow water depth. According to this wastewater treatment apparatus, energy to be consumed can be saved and toxic chemical substances such as dimethylformamide as a toxic chemical substance can be completely decomposed by unlimited microorganisms.

Abstract: The invention offers a method and apparatus for solubilizing excess sludge, having a high solubilizing ability, a low total cost, and capable of reducing the size of facilities. The method for reducing excess sludge comprises adding a solubilizing agent to excess sludge generated by microbial treatment of organic sewage, applying ultrasonic waves, applying a reduced pressure swelling step, then returning the result to the microbial treatment, whereby the volume of the excess sludge can be reduced. The apparatus for reducing excess sludge comprises means for adding a solubilizing agent to excess sludge generated by applying a microbial treatment to organic sewage, ultrasonic wave applying means for applying ultrasonic waves, and reduced pressure swelling means provided downstream of the ultrasonic wave applying means for applying a reduced pressure swelling process to the excess sludge.

Abstract: A process is described for the biological treatment of waste water containing a specific component such as ammonia, wherein the waste water together with surplus sludge from an activated sludge reactor is treated in a bioaugmentation reactor, applying a hydraulic retention time in the continuously or discontinuously operated reactor which is shorter than the sludge retention time by retaining part of the sludge in the reactor and continuing the use of the separated part in the reactor. The non-retained part of the sludge, together with the effluent of the bioaugmentation reactor, is added to the activated sludge reactor.

Abstract: There is provided a process for treating industrial wastewater that substantially eliminates the generation of excess solids in the system requiring mechanical removal. The wastewater undergoes an equalization step wherein hydraulic flow is smoothed and the pH of the wastewater is adjusted to near neutral pH conditions. The equalized wastewater is then transferred to aeration tanks where the organic process wastes are absorbed, metabolized, or otherwise biodegraded by the microorganisms in the mixed liquor in the aeration tanks. After the aeration step, the wastewater is separated by gravity in a clarifying step to separate the wastewater into a liquid phase and a semi-solid phase. The clarified liquid phase is withdrawn from the clarifier and discharged, while the semi-solid phase is transferred either directly back to the aeration/biological treatment step, as recycle-activated sludge, or into a bioreactor as waste-activated sludge. In the bioreactor the semi-solid phase is subjected to active aeration.

Abstract: A method of preparing a microbial culture for wastewater treatment comprising the steps of supplying an aerated material derived from an aeration tank (13) to a bioreactor (17) and cultivating a microorganism existing in the aerated material by adding a culture having a relatively long preservation time and a large number of effective microorganisms.

Abstract: A method and apparatus are disclosed for treating an organic waste water which are capable of utilizing compact equipment by reducing the quantity of a sludge to be treated. Organic waste water (A) is subjected to an aerobic biological treatment in a biological treatment tank (3). Then, solution (B) obtained by the treatment in the biological treatment tank (3) is solid-liquid separated into treated water (C) and sludge (D) in precipitation tank (5). A portion of the sludge (D) separated in the precipitation tank (5) is returned to the biological treatment tank (3) through a route (6). A portion (E) of the sludge separated in the precipitation tank (5) is concentrated by a concentration device (8). Thereafter, the concentrated sludge (E) is solubilized by thermophilic bacteria in a solubilizing tank (10).

Abstract: The invention relates to a method for purifying protein containing waste water, In which a) a first insoluble material is caused to form in the waste water, b) the mixture obtained in step a) is separated to form pre-purified waste water, c) the pre-purified waste water is treated with aerobic microorganisms and d) the mixture obtained in step c) is separated to form finely purified waste water, and in which step b) and step d) are carried out in the same device. Preferably, steps b) and d) are alternately carried out in the same device.

Abstract: A wastewater treatment process having improved solids separation characteristics and reduced biochemical oxygen demand (BOD) in the purified wastewater comprising the steps of: passing wastewater through a main aerobic biological oxidation zone and therein oxidizing a portion of the BOD a portion of the ammonia nitrogen content (NH.sub.

Abstract: A process for treating a water containing chlorinated organic compounds, wherein a microorganism is introduced from a degradation tank to a separation tank and an energy source is supplied to the microorganism separated in the separation tank. A water-treatment apparatus having a structure capable of continuously introducing water to be treated through a degradation tank, a separation tank and a reactivation tank. A loss of the energy source such as methane or propane discharged from the separation tank can be reduced. A water-treatment apparatus having a degradation tank and a separation tank, wherein a microorganism can be cultivated in the separation tank. The reactivation tank can be omitted, whereby the entire size of the apparatus can be reduced.

Abstract: A process for reducing the amount of excess sludge by aerobically treating an aqueous organic waste in an aeration tank in the presence of a biosludge containing aerobic microorganisms, subjecting the resulting mixed liquor to a solid/liquid separation, the so-separated liquid phase being discharged as treated liquor, and supplying at least a part of the separated biosludge, after having been treated with ozone, to the aeration tank, wherein the ozone treatment is realized by passing a mixed flow of a biosludge-containing liquor to be treated or a liquor containing the ozonized biosludge and of an ozone-containing gas through a flow-down pipe in a downward flow and introducing the flow into an ozone-treating vessel in a state in which the ozone-containing gas is dispersed as finely disintegrated bubbles, whereby the clogging of a gas diffuser due to the adhesion of the biosludge is avoided and ozone treatment is attained at a high ozone yield.

Abstract: This method measures the soluble phosphorus concentration in the treated water for at least two different places of the treatment line: at the intake of the secondary clarification step to obtain a measurement P1 and at the outlet of the treatment line to obtain a measurement P2, the measurement P1 determining the amounts of the product precipitating the phosphorus in the liquor of at least one of the tanks in which the anoxic or aerobic steps are carried out upstream of the secondary clarification. The measurement P2 is continuously compared to the measurement P1 so as to detect a possible salting out of the phosphorus at the level of the secondary clarification. When the difference between these two measurements (.DELTA.P1-P2) is noted, one of the two following measures occurs: supplementary injection of the precipitating product, before the secondary clarification, or modification of the flow rate of recirculation of the sludge of the clarification step towards the first anaerobic step.

Abstract: A process for reducing the production of biomass during activated sludge treatment of pulp and paper mill effluents, involving a conditioning of the recycled activated sludge (RAS) prior to its return into the aeration tank is described. The conditioning is typically performed within the sludge return line and involves RAS exposure to a waste acidic effluent originating from bleach plants of kraft, sulphite mills or other mill sources.

Abstract: An aerobic treatment process is operated to reduce overall oxygen requirements, to maintain general pH balance and to produce a low-coliform solids effluent. From the system's clarifier a slurry of concentrated solids is moved to a premix basin, where the slurry is vigorously aerated for a sufficient time to raise microbial activity and dissolved oxygen content. The aerated, microbially active sludge is then moved to a gravity thickener basin, in which solids are allowed to settle to the bottom without aeration, to establish a quiescent state in the settled sludge and also an anoxic stage. This causes the sludge to be denitrified by microbial action, raising and stabilizing the pH of the sludge. Separated supernatant liquid is decanted and removed from the gravity thickener. The sludge is moved into an aerobic digester, where the sludge is aerated and nitrification occurs but using less aeration than normally required in a digester, due to the effect of anoxic/aerobic phases.

Abstract: A method of purifying waste water biologically, in which at least one biological reaction is performed in at least one biological reactor containing microorganisms in activated sludge, and the waste water is separated from the activated sludge in a clarification basin, with at least a fraction of the activated sludge from said biological reactor being recirculated, wherein, prior to admitting the waste water to be treated into said biological reactor, at least a fraction of the polluting particles in suspension therein are separated out therefrom, the separated polluting particles are sent to a sludge activation reactor that is separate and disposed in parallel, the separating polluting particles are used as the main substrate for the development of microorganisms in strict aerobiosis, and the superactivated sludge obtained in this way is injected into the biological reactor(s).

Abstract: A method is described for the continuous disintegration of microbial sludge in a sewage clarification or sewage treatment plant wherein the microbial sludge is decomposed biologically by bacteria and the resultant sludge (5) is exposed to sonic radiation in a treatment vessel (1) in order to split the cell walls of the microorganisms. With that, the sonic radiation shall be generated asymmetrically in the treatment vessel (1). The intensity of the sonic exposure lies-in an area of 500 to 1500 W/m2 and the sludge (5) is fed with a mean dwell-time of 2 to 4 minutes in counter-flow through the treatment vessel (1). The device for carrying out the method possesses a treatment vessel (1) with an eccentrically arranged sonic resonator arranged within (7).

Abstract: A method and apparatus for wastewater treatment is provided which can prevent any decrease in permeation efficiency of a submerged membrane without involving an increase in operating cost and sludge generation, and which can treat high concentration organic wastewater efficiently and without dilution. The wastewater treatment method has the steps of: concentrating domestic sludge by means of a first submerged membrane to produce thick sludge; mixing the thick sludge into a water to be treated, and introducing the water to be treated which is so mixed with the thick sludge into an anaerobic treatment portion for anaerobically treating the same; and introducing the anaerobically treated water from the anaerobic treatment portion into an aerobic treatment portion having a second submerged membrane disposed therein to subject the water to aerobic treatment.

Abstract: A wastewater treatment process having improved solids separation characteristics and reduced biochemical oxygen demand (BOD) in the purified wastewater comprising the steps of: passing wastewater containing suspended solids and biodegradable organic substances through a main aerobic biological oxidation zone; passing the effluent from said aerobic biological oxidation zone to an aerobic/mixing zone and therein mixing said effluent with effluent from the anoxic/anaerobic zone; passing the effluent from said aerobic/mixing zone to a settling zone and therein separating purified wastewater and sludge containing suspended solids; passing a portion of the sludge formed in the settling zone and volatile acids to an anoxic/anaerobic zone; and recycling an effective amount of the effluent from said anoxic/anaerobic zone to said aerobic/mixing zone.

Abstract: A method for treating wastewater is useful in treatment of biomass (sludge) resulting from wastewater treatment, particularly for biological sludges of aerobic, facultative and/or anaerobic origin. The invention relates fractionation of microorganisms and organic materials within the sludge by mechanical shearing, in combination with heat, chemical and/or biochemical treatment to improve waste treatment and to release nutrients for recirculation for use by microorganisms in the waste treatment system.

Abstract: The present invention entails a method and system for enhancing biological nitrification in a wastewater treatment process. The process entails both a mainstream wastewater process and a sidestream process wherein the sidestream process produces an abundant supply of supplemental nitrifiers that are in turn directed into the mainstream for assisting in carrying out the nitrification process in the mainstream. Specifically, the sidestream process includes directing a liquid stream (such as a dewatering liquid) having a high ammonia concentration at an elevated temperature into a sidestream nitrification zone which is operated at conditions which maximize production of nitrifiers therein. Afterwards, the resulting nitrifiers produced in the sidestream nitrification zone are directed into the mainstream where the nitrifiers function to enhance nitrification in the mainstream and allows operation at low sludge retention time conditions where nitrification otherwise could not be sustained.

Abstract: A wastewater treatment process having improved solids separation characteristics and reduced biochemical oxygen demand (BOD) in the purified wastewater comprising the steps of: passing wastewater containing suspended solids and biodegradable organic substances through a main aerobic biological oxidation zone and therein oxidizing a portion of the BOD and converting a portion of the BOD into additional suspended solids and at least a portion of the ammonia nitrogen content (NH.sub.3 --N) of the wastewater is oxidized to nitrate nitrogen (NO.sub.