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 an aerobic biological oxidation zone and therein oxidizing a portion of the BOD and converting a portion of the BOD into additional suspended solids; 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 having reduced BOD and suspended solids, and sludge containing suspended solids; passing a portion of the sludge formed in the settling zone to an anoxic/anaerobic zone and therein increasing the extracellular polymer content of said sludge; and recycling an effective amount of the effluent from said anoxic/anaerobic zon

Abstract: The present invention refers to a process for wastewater treatment, wherein the amount of soluble organic matter is reduced by means of addition of nitrate. A relief of the wastewater treatment plants is obtained by the fact that the agent is added as early as possible in the pipe line net. The addition of nitrate may be controlled by measurement of the redox potential.

Abstract: Wastewater containing impurities refractory to secondary treatment is first introducted into an aerobic biological treatment stage operating with an oxygen-enriched stream and subsequently into a precipitation stage where the biologically treated wastewater is combined with Ca(OH).sub.2 to precipitate Ca(OH).sub.2 CaCO.sub.3 sludge which adsorbs or occludes impurities. The clear liquid, separated from the resultant sludge, is passed to a second precipitation stage where it reacts with a CO.sub.2 and oxygen-containing waste gas at least in part from the aerobic biological treatment stage, thereby forming additional CaCO.sub.3. Waste gas withdrawn from the second precipitation stage, being enriched in oxygen is recycled to the aerobic biological treatment stage.

Abstract: An adaptive filter concentrate flow control system and method includes a filter system, a pumping system driving feed fluid, concentrate and filtrate flowing through the filter system and a flow control system controlling the pumping system to maintain optimum filtrate flow rates or minimum feed flow rates along a control surface in a three dimensional transmembrane pressure--feed fluid rate--filtrate flow rate space. Actual sensed operating point data is used to locate the control surface so as to assure an optimized filtrate flow rate or minimized feed flow rate at which reversible blocking of the membrane has begun to occur without irreversible blocking or plugging. The system is advantageously employed to control and maximize the flow of plasma in a plasmapheresis system or to minimize the rate at which blood is withdrawn from a donor and introduced into the system while achieving a fixed rate of plasma flow.

Abstract: A method of treating wastewater using an aeration tank of the type having an interior divided into at least a first chamber and a last chamber with each of the chambers having a lower portion and an upper portion and having liquid passageways in the lower portions of each of the chambers and gas passageways in the upper portions of each of the chambers for allowing liquid and gas to pass sequentially through each of the chambers from the first chamber to the last chamber, having an effluent outlet associated with the last chamber of the aeration tank for allowing treated water to exit the aeration tank; and having agitator means to enhance oxygen transfer from the upper portion to the lower portion of the aeration tank.

Abstract: A fluidized-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fluidized-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fluidized-bed bioreactor.

Abstract: In a process for the biological purification of wastewater, the wastewater is mixed with activated sludge in an aeration basin in the presence of carrier particles for microorganisms and is aerated with an oxygen-containing gas. Treated wastewater and free activated sludge are discharged from a discharge zone of the aeration basin downstream of an initial zone at least 20% up to 70% of the length of the aeration basin.

Abstract: Abnormally lowered reduction in the rate of phosphorus removal from influent wastewater in an activated sludge system, occurring particularly following periods of increase in flow rate of wastewater entering the system, is avoided by controlling the maximum F/M in that portion of the system in which oxidation is occurring so as not to exceed 0.9 and maintaining a defined relation between the maximum and minimum F/M during any 24 hour operating period.

Abstract: The present invention concerns a process and an installation for the treatment of waste waters issuing from the manufacture of sauerkraut, this process and installation comprising a biological treatment step for treating waste waters leading to the formation of a precipitate, and the subsequent treatment of the aqueous separated phase in a reverse osmosis apparatus.

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: In the biological purification of wastewater containing organic impurites, wherein the wastewater is passed through a reaction (1), e.g., continuous flow-stirred tank having circulating means (12) to achieve thorough mixing therein, or a fluidized bed or suspended bed type reactor, the wastewater is aerated in the presence of activated sludge with an oxygen containing gas fed through a gas feed conduit (9), and in a post clarification stage (5), the wastewater-activated sludge mixture from the reactor (1) is separated into purified water and sludge, the improvement comprises conducting the biological purification in the reactor (1) in the presence of a carrier material for microorganisms. The carrier material comprises particles of macroporous material having a low specific gravity, and in piece and/or granulated form in an amount such that the suspended individual particles are freely movable in the wastewater. Soft polyurethane foam particles are especially preferred as the carrier materail.

Abstract: An integral clarifier is provided that operates without a pump by deriving the clarifier feed stream and its accompanying pump head from the flow being pumped through the draft tube of a draft tube circulator/aerator assembly in a complete mix system or in a basin oxidation ditch. The clarifier feed stream is delivered to the clarifier with this pump head substantially intact to create a differential hydraulic head between the surface of the clarified liquor within the clarifier and the surface of the mixed liquor within the complete mix tank or within the endless channel of the barrier oxidation ditch. The clarifier may be located in any suitable place but is preferably alongside the complete mix tank or alongside the discharge channel of the barrier oxidation ditch, within the discharge channel so that its upstream side forms the barrier, or surrounded by the endless channel, particularly if the clarifier and the ditch are circular in shape.

Abstract: Method for cleaning waste water, wherein the waste water (19) and oxygen gas (31) are flowing in opposite directions through a cylindrical multireactor (20) having a central rotatable pipe (24), the multireactor comprising a number of bioreactors and at least one separation chamber (75). The average pressure difference between two successive bioreactors is at most seven meter water column. The bioreactors are separated from each other by stationary walls (40, 41, 48, 55, 60), and each bioreactor has its own mixing device (50) for mixing waste water and oxygen gas.

Abstract: Sewage is oxygenated and clarified in a tank having an open-bottomed stilling chamber located above an open-topped chamber. Oxygenated sewage is discharged into the stilling chamber where its velocity is reduced, with sewage passing from the stilling chamber into the open-topped chamber being precluded from flowing horizontally along the tank bottom, and upwardly into the clarified sewage.

Abstract: A substantially constant loading waste water treatment process and apparatus subjects the waste water to treatment with recycled sludge and oxygen in an activation basin. The suspension is separated into sludge and effluent and a portion of the recycled sludge, when the waste loading exceeds a threshold value, is aerated before being introduced into the activation basin in a separate aerating basin.

Abstract: In a process and apparatus for conducting an activated sludge process in an activation basin having multiple sections, preferably at least three sections are provided for conducting the process with each succeeding section being larger in volume than the previous section by an amount about equal to the volume of the first section. It is preferred that the process be conducted in the first section by feeding the first section with an oxygen enriched gas, and with the next section in line fed with the exhaust from the first section, and the third section being aerated with air. In a specific refinement, there are provided four sections with the first two sections sealed with respect to the atmosphere.

Abstract: A process for the secondary treatment of wastewater by a modified air activated sludge system comprising aerating wastewater containing bacteria until the BOD level of the wastewater is reduced by at least 90%, the food to microorganism ratio of the wastewater being greater than one, introducing the aerated wastewater under pressure to a flotation cell to separate suspended solids including bacteria from the pressurized wastewater by dissolved air flotation clarification, recycling said suspended soilds and bacteria to said aeration step in an amount sufficient to maintain said food to microorganism ratio and removing and disposing of the remaining reduced BOD level wastewater.

Abstract: In a long vertical shaft bioreactor for the treatment of degradable wastes in a circulating loop, a process is provided for separating and treating the slowly biodegradable components of the waste. The process comprises the steps of aerating and oxidizing the waste liquor in the reactor to produce an effluent and a foam which foam contains the slowly biodegradable components, which have not been degraded in the oxidizing step, separating and collecting the foam, collapsing the foam and subjecting the collapsed foam to further aeration/oxidation treatment to produce a treated effluent. The thus further treated effluent is returned to the bioreactor for reprocessing.

Abstract: A method and apparatus is disclosed for purifying the waste water in an avated sludge-waste water mixture. In dependence upon the state of purification of the waste water, the mixture is ventilated in automatically controlled manner by a gas comprising molecular oxygen. The automatic control of ventilation is exercised by the use of a monitoring device which measures the visible depth of the waste water and, depending upon the measured value, starts-up or switches-off the ventilation.

Abstract: In the process for decreasing the COD-content of effluent by treating with hydrogen peroxide in the presence of a transition metal compound, the improvement which comprises adding to the effluent about 5 to 40% of the calculated quantity of H.sub.2 O.sub.2 required for the total oxidation of the total COD-content of the effluent, the transition metal compound being dissolved in the effluent in an amount such that the molar ratio of H.sub.2 O.sub.2 to transition metal is from about 30:1 to 3:1, bringing the pH initially to about 2 to 9, maintaining the effluent at about 5.degree. to 100.degree. C., and separating from the effluent whatever material has flocculated. Thereafter the effluent can be subjected to conventional biological degradation such as by the activated sludge process.

Abstract: In a long vertical shaft activated sludge bioreactor for the treatment of waste water and the flotation/separation of solids therefrom, an improvement is provided whereby fluctuations in flow through the bioreactor are maintained level without the use of complex control mechanisms and whereby separation from the effluent of dispersed air bubbles occurs directly in the flotation/separation vessel rather than in the shaft or an auxiliary vessel. The improvement provides for the installation of a holding reservoir between the shaft and the flotation/separation vessel. Influent passes through the reservoir on its way to the bioreactor and some make-up effluent from the flotation/separation vessel is directed into the holding reservoir as the level of liquid in the reservoir falls. In addition, means are provided in the separation/flotation vessel to split off large dispersed gas bubbles which would otherwise disrupt sludge flotation.

Abstract: An activated sludge treatment method of waste water which comprises (a) the step of micronizing as far as possible the sludge in the waste water containing the BOD component to a degree not to have the cells of the microorganisms therein broken or destroyed and adsorbing the BOD component to the micronized sludge, and (b) the step of oxidizing the BOD component adsorbed to the sludge by blowing in an oxygen-containing gas and flocculating the sludge. By this method, the treatment of waste water is accomplished with a shortened residence time of the waste water in an installation for the treatment and with the production of excess sludge in a considerably reduced amount.

Abstract: A process for digestion of sludge wherein the sludge is oxygenated in a first digestion zone at temperature of from 35.degree. to 75.degree. C. to partially reduce the biodegradable volatile suspended solids content of the sludge. The partially stabilized sludge is anaerobically digested in a covered second digestion zone at temperature of from 25.degree. to 60.degree. C. to further reduce the biodegradable volatile suspended solids content of the sludge, to less than about 40% of the biodegradable volatile suspended solids content of the sludge introduced to the first digestion zone.

Abstract: For the treatment of wastewaters containing substantial BOD and substantial calcium ion concentrations, e.g., effluents from the washing and flushing cycles of sugar manufacturing plants, by an activated sludge process, under aeration with an O.sub.2 -containing gas, the improvement which comprises introducing a CO.sub.2 -containing gas having a concentration of CO.sub.2 higher than that of air into liquid present in the activated sludge system to precipitate calcium ion as calcium carbonate thereby lowering the pH of the liquid and facilitating the separation of the activated sludge solids and the bacterial action of the activated sludge process.

Abstract: A process and apparatus for the treatment of aqueous waste materials or effluents, particularly the aqueous waste materials of bottling plants and installations, in which a trickling element is employed for the basic rough processing to effect the removal of biological oxygen demand (BOD). The discharge stream of effluent from the trickling element is conveyed into an oxidation-reaction tank, providing for the chemical oxidation of light organic floc resulting from biological action in the trickling element and further BOD reduction, and for the oxidation of any biomass sloughing off the media in the trickling element. The treated waste material or effluent discharge emanating from the oxidation-reaction tank is conducted through a mixing tank which is adapted to simultaneously receive the final rinse waste effluent from the bottling plant, and to intermix the two effluents and subject these to further oxidation treatment through the intermediary of admixing air therewith.