Abstract: An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. A baffle and long folded ribbons inside the chamber promote mixing of the developer and fixer. A source of iron ions such as fine steel wool is immersed in the fluids. Ion exchange between the steel wool and the photographic fixer recovers silver from the fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber.

Abstract: Method for treating drilling effluents containing ligno-sulfonates wherein, successively, sulfuric acid is injected in order to cause coagulation, a cationic polyelectrolyte is injected to cause a flocculation and solids are separated from the liquid by centrifugation or dewatering compaction.

Abstract: Biological decontamination and the avoidance of accumulation of dissolved solids are both achieved in captured and recirculated water systems by a continuously operating system involving the use of a chemical filtration unit, removal of dissolved solids as they are concentrated at the filtration unit, a disinfectant treatment, and the protection of the chemical filtration unit from degradation by the disinfectant where necessary.

Abstract: A compact waste treatment facility comprises an optional surge basin, an aeration basin, a settling basin, and a digester basin. The basins are interconnected in the order named for therewith providing a sequentially arranged waste treatment facility. Each of the basins is comprised of six integral walls which are substantially equiangularly disposed one to the other so that each basin is hexagonally shaped in plan. Each basin has a wall common with the basin interconnected therewith. Each basin has an assembly for supplying fluid treated therein to the next interconnected basin. An aerator is provided in the aeration basin for causing fluid flow thereabout.

Abstract: Plant to precipitate suspended matter out of water, such as surface run-off water, industrial waste water, biologically treated waste water and landfill leachates with in-pipe flocculation, a filter filled with granular filter material situated above the sedimentation tank of the plant the direction of flow through which is from top to bottom and a backwash tank and whose subsequent sedimentation and filtration stages comprise the following features: that the backwash tank for filtered water is situated above the filter; that a float seals off an aperture with an enlargened cross-section connecting the filter with the backwash tank in a position raised by buoyancy; that a bypass directs the treated filtered water past the float to the backwash tank if the said aperture is closed off; and that the sludge outflow pipe in the floor of the sedimentation tank and the sludge valve in the sludge outflow pipe are directed against gravity to such an extent that when the sludge valve in the sludge outflow pipe is opene

Abstract: A dewatering porocess and apparatus for recovering water from waste drilling fluid for concurrent reutilization in an active drilling operation includes a storage area, an intermixer for introducing treatment chemicals into the waste drilling fluid and a centrifuge. Flocculation is chemically induced in the waste drilling fluid as it passes through the intermixing means for introducing treatment chemicals into the waste drilling fluid. The waste drilling fluid is then transferred to the centrifuge wherein it is separated into solid waste and clear reuseable water. The water is returned to the storagge area and may be chemically adjusted prior to being returned to the drilling rig.

Abstract: A process and apparatus for reducing sludges, especially those sludges containing heavy metals and generated in electroplating, to a solid state where the toxic constituents of the waste are prevented from leaching. The process involves mixing a metallic soap with the sludge and then using low-temperature induction heating to form coacervate bonds that encapsulate the toxic waste particles in a pumice-like matrix. The apparatus allows a small amount of metallic soap to be thoroughly mixed through sludge and a continuous ribbon of the resulting putty-like waste to be fed into a series of microwave drying ovens and evacuation chambers. After the drying and dewatering sequences, the apparatus extrudes a pumice-like solid suitable for disposal in accordance with EPA regulations.

Abstract: A method and apparatus for treating a liquid mixture to separate a clarified fraction therefrom leaving a concentrated sludge fraction involve injecting a flocculent material into the liquid mixture; and inletting the liquid material and the flocculent maerial tangentially into a vertical tank having a perforated plate spaced from its upper end dividing the tank into an upper chamber and a lower chamber, a to produce a flow in the lower chamber having a rotational velocity in the horizontal direction adjacent the outer periphery of the lower chamber, and a lower rotational velocity in the horizontal direction adjacent the center of the lower chamber. The holes in the perforated plate define reduced-area passages from the lower chamber to the upper chamber producing a vertical flow of low velocity in the lower chamber and of higher velocity through the passage in the perforated plate.

Abstract: A device for separating a moving fiber from processing fluid is disclosed and claimed. A chamber defining hydrophilic and hydrophobic flow paths respectively is exemplified. The device is placed so that substantially all water associated with processing exits via the hydrophilic path while the fiber exits via the hydrophobic path.

Abstract: A method is provided for removing a solid phase from a liquid substance, which is kept in a continuous turbulent flow. The method is characterized by adding simultaneously at consecutive places in the flow direction of the liquid substance, cement, iron (III)-chloride-sulfate and an anion polyelectrolyte. Cement is added at a first place, iron (III)-chloride-sulfate at a second place and anion polyelectrolyte at a third place.

Abstract: The fluidized bed reactor for biological treatment of effluent essentially comprises a container (1) over the base 2 of which elongated gassing units having gas exit apertures (5) are arranged parallel to one another, in such a way that in each case two neighboring circulating currents (8, 9) in mirror-image symmetry are produced in the reactor. In addition, the reactor (1) is supplied with a retention system (16) arranged on the outside for the separation of carrier particles for biocatalysts suspended in the effluent.

Abstract: A friction-reducing lubricating-oil filter for Internal Combustion Engine and in which a solid-lubricant-feeding equipment is equipped on the lubricating-oil duct where the lubricating-oil has been finely cleaned and has not got to the friction parts, which is wholly sealed and is filled with solid lubricant, on which there are several holes evenly arranged; when the lubricating-oil flows over the outside surface of said solid-lubricant-feeding equipment and said holes, because the static pressure of the flowing liquid is lower, the solid lubricant in the solid-lubricant-feeding equipment is drawn out through said holes and mixes with the lubricating-oil. This friction-reducing lubricating-oil equipment doesn't need any other driving equipment and can transfer the solid lubricant to the friction parts without filtering out by the filter, and therefore is not only simple in structure, but also very effective in friction-reducing.

Abstract: An apparatus and method for stabilizing sludge such as the sludge produced by municipal waste water treatment plants includes thickening of the sludge to a dry solid content in the range of 3% to 8% before feeding it to at least one comparatively small reactor tank that extends horizontally and has an inlet and outlet adjacent opposite end walls. The system preferably utilizes multiple tanks stacked one above the other and connected in series. The tanks have an in-built mixer that sweeps through the interior of the tank. The mixer is eccentrically mounted so that its mixing members carry the sludge through the uppermost portion of the tank interior and are spaced from the bottom surface of the tank. A sparger is located either in the inlet or in the bottom clearance of the tank to introduce microscopic bubbles of oxygen and ozone into the sludge. A pressure regulating valve controls the flow of the stabilize sludge from the uppermost reactor tank.

Abstract: A mobile tank for decontamination of waste or ground water contains multiple cells for biological treatment and clarification of the water. Systems are provided for aerating the treatment cells and for recycling activated bacteria from the clarifier cell to the primary treatment cell.

Abstract: A method and system for biofouling control of fluid containing structure of susceptible biofouling, wherein chlorine, hot water and/or some other control agent is injected by plural stages into the boundary layer, and chlorine residual, water temperature, or some other respective control parameter is maintained in the boundary layer just upstream of the next injection point.

Abstract: An activated-sludge sewage treatment plant employs a hybrid aeration chamber comprising a primary, complete-mix section to which sewage influent and recycle sludge are introduced and treated by aeration and mixing sufficient to provide an effluent having biological oxygen demand in the range of approximately 15 to 75 parts per million, and a secondary hydraulic plug-flow section which receives the effluent. In the secondary section the effluent is treated by incrementally introducing air thereto as the same flows through the secondary section to progressively reduce the biological oxygen demand and thereby provide a final, treated effluent having a biological oxygen demand of approximately 5 parts per million.

Abstract: A thickener well is provided in one end of a digester orbital ditch having a pair of channels and an elongated center partition spaced from a pair of ditch endwalls, the overall ditch forming a basin for digestion of wasted sludge. A curved endwall of the ditch provides a common curved top outer peripheral wall of the thickener well. The remainder of the well has a cylindrical configuration integral with the orbital ditch bottom and extending downwardly therefrom to a position below the horizontal plane of the ditch bottom. A sludge raking structure is positioned at the bottom of the well for periodically raking settled sludge into a sludge outlet at the bottom of the well. A surface aerator is provided between and spaced from the other ditch endwall and a juxtaposed end of the partition or other aeration apparatus mounted in a channel(s) to aerate and propel a liquid-solids sludge mixture wasted from a secondary treatment apparatus and fed into the orbital ditch.

Abstract: The invention relates to an installation for aerobic biological purification of pollutant-containing water, which installation consists of an axial-flow submerged reactor and a sedimentation tank for separation of the biosludge from the purified water. The reactor is a pipe containing a two-stage activated-sludge chamber, which pipe contains (a) a first activated-sludge stage in which a driving-jet nozzle is disposed at the downstream end for the dispersion of the air and the microorganisms in the waste water to be purified, and (b) a second activated-sludge stage in which internals are disposed for homogeneous dispersion of the gas bubbles and the microorganisms as well as for immobilization thereof.

Abstract: An electrolytic ion generator (A) supplies reverse polarity current to an electrode unit (B) having metallic electrodes (20, 22). The electrodes are composed of lead, tin, and copper in the approximate proportion of 2, 10, and 88 percent. A timer (52) reverses current to the electrodes periodically to reduce ion bridging and electrode shorting and wear.

Abstract: A pump driven by air only is disclosed for providing simultaneous aeration and flow at right angles to the rising air. The pump produces in a shallow tank particle-suspending turbulence which is particularly useful for growth of marine organisms in a sun-exposed tank confined shallow brine solution. The pump is preferably installed in a rectangular tank divided by a baffle between the two tank side walls. The baffle extends parallel to the major axes of the rectangle and stops short of both tank end walls. The fluid is pumped around this baffle in an oval flow pattern. On the shallow bottom of the tank on both sides of the baffle, there is a repeating foil shaped bottom with a manifold for discharging air. The foils of the bottom are generated at right angles to the baffle and oriented from leading edge to trailing edge in the direction of intended fluid rotation around the baffle in the tank. Air is pumped and discharged from the manifold in a rising curtain.

Abstract: A solution of water soluble conveyor lubricant is continuously recovered from a moving conveyor through a suction bar. The lubricant is treated with a bactericide and the pH is adjusted as needed. The solution is then recycled at least once to obtain about a 50%-90% recovery.

Abstract: A solution of water soluble conveyor lubricant is continuously recovered from a moving conveyor through a suction bar. The lubricant is treated to reduce suspended solids, heat sterilized, the pH adjusted, and a bactericide is added. The solution is then recycled at least once to obtain about a 50%-90% recovery, and then is discharged. The process saves a significant amount of water, in addition to lubricant.

Abstract: Cleaning of multi-pore diffusion elements in place with cleaning gases while submerged in liquid media by applying said cleaning gases intermittently or continuously to said diffusion elements between predetermined limits of operating pressure and flow through flow regulation means and plenums for the respective diffusion elements.

Abstract: Water supply in aircraft for on-board use in conjunction with water outlets in lavatories and a galley, includes a waste water tank connected to at least some of the waste discharge outlets on board of the aircraft; a water purifying plant connected to and receiving water from the waste water tank; and a fresh water tank having outlet means, connected at least to some of the water outlets, and having an inlet connected to said water purification plant, for receiving therefrom purified waste water; an additional tank for drinking water may be provided as well as a separate supply line therefrom leading to drinking water outlets on board of the aircraft.

Abstract: A separator comprises a vessel having an outer wall (2) and an end wall (3). A body (14) adjacent the end wall (3) defines with the end wall (3) an annular opening (15). In use, a mixture of, for example water and solid material, is introduced into the vessel through a first inlet (4). A circulating motion takes place in the vessel and the solid material falls to the end wall (3) and is removed through the opening (15) to an outlet (6) while clean water flows from the top of the vessel through an outlet (8). In order to increase the energy in the lower region of the vessel so as to assist removal of the solid material, water from the outlet (8) is passed through a pump (P) and reintroduced as energizing fluid to the vessel through a recirculating port (44). Energizing fluid may be taken from sources other than the outlet (8). Various alternative forms of separator are disclosed.

Abstract: A method and apparatus for degrading biodegradable waste through bioaugmentation, the waste treatment apparatus comprises a waste treatment tank including a multistage waste treatment section and a waste settling section, the multistage waste treatment section comprises a plurality of waste treatment chambers, a blending device to emulsify and aerate the waste in at least one waste treatment chamber, a transport system to selectively supply bacteria to the multistage waste treatment section, to selectively transfer waste and bacteria to and from the multistage waste treatment section and to selectively transport sludge to and from the waste treatment tank and a fluid transfer port formed between the final waste treatment chamber and the waste settling section to transfer reduced waste to the waste settling section, the method comprises reducing the biodegradable waste treatment section aerating and emulsifying the bacteria and waste and selectively circulating the bacteria and waste between the waste treatmen

Abstract: An aerobic wastewater treatment system including an aeration tank, the interior of the aeration tank being divided into at least a first chamber and a last chamber, each of the chambers having a lower portion and an upper portion; structure for allowing influent wastewater to be treated and return sludge to enter the lower portion of the first chamber of the aeration tank; structure for allowing mixed liquor to flow sequentially through the lower portions of each of the chambers; an effluent outlet associated with the last chamber of the aeration tank for allowing mixed liquor to exit the aeration tank; agitator structure associated with each chamber of the aeration tank for enhancing oxygen transfer from the upper to the lower portions of each chamber; structure for introducing high-purity oxygen into the first chamber of the aeration tank and for maintaining the pressure in the upper portion of the first chamber of the aeration tank to at or below existing atmospheric pressure; structure for controlling gas

Abstract: A method and apparatus for the removal or reduction of inorganic contaminants, hardness, radionuclides, organic contaminants, odor, turbidity, discoloration, and objectionable taste from water, subjects the water to lime-phosphate softening, aeration, sedimentation, filtration and ion exchange in an automatic cycle especially suited for home and small commercial usage. The raw water, such as well water, is first subjected to a cold lime softening and aeration treatment, then to a phosphate treatment followed by settling and filtering. The thus treated water is supplied to a pressurized tank feeding a conventional ion exchange water softening unit as the water is tapped for use. No heat input is needed but the treated water can be heated as desired for use. An electrical control system regulates the water and chemicals input agitation, aeration, the time of chemical treatment in successive stages and the maintenance of a desired head pressure for the treated water.

Abstract: Apparatus and methods are disclosed for intimately mixing and contacting first and second fluids for purposes of scrubbing and cleaning one of the fluids with the other. The apparatus includes a venturi mixer device having a nozzle and feed conduit for mixing two fluid streams together. In addition, the venturi mixer device has an impingement member upon which the mixed stream of fluids impinge immediately following the mixing of the streams of fluid. The venturi mixer devices are preferably arranged in a cascade arrangement with subsequent devices being spaced a vertical distance from the previous respective devices. First and second fluids are mixed together in the initial venturi mixer device. The mixed effluents from the initial and intermediate venturi mixer devices are used as the drive fluid for subsequent, respective, downstream venturi mixer devices to further mix additional second fluid to the mixed effluents.

Abstract: In the method of treating high-concentration organic waste water in dependence upon microorganism, waste water is first anaerobically treated in an anaerobic operation tank in dependence upon anaerobic bacteria groups and methane bacteria groups; in the second step, the waste water is further aerobically treated repeatedly in an aerobic operation tank, and an organic substance as hydrogen donor (raw waste water) is supplied to the aerobic operation tank before the succeeding aerobic treatment; in the third step, ozone treatment is effected to decolor the treated water. Two speed bacteria culture tanks for sludge bacteria and methane bacteria are provided separately to supply bacteria to the anaerobic operation tank for providing further reliable decomposition and denitrification of organic substance into methane and nitrogen gasses.

Abstract: The instant invention relates to an apparatus for treating wastewater containing bentazon by decomposing the bentazon therein and thus eliminating or substantially reducing the bentazon content. This apparatus includes means for adjusting the pH of the wastewater to a value of less than 7 and heating it to a temperature of at least about 60.degree. C.

Abstract: Double valve apparatus is used in a swimming pool chlorinating system for injecting chlorine gas into a swimming pool when a swimming pool pump is operating. Two valve elements move on and off two valve seats for preventing air from bleeding back to the water pump when the pump is not operating and for preventing back pressure in the system from introducing water into the chlorine gas line.

Abstract: Apparatus for use in removing waste from a fish culture system including a tank through which water from the system may be circulated, filters mounted in upright and spaced apart relation across the tank so that the water circulates successively through them, and tubes for injecting air into the water on the upstream side of each filter.

Abstract: Ozonization of the bath water taken from the reservoir (1) occurs according to the invention utilizing only 1% of ozone while using from 1 to 1.2 g/h of ozone in 700 l/h of (untreated) air from a convenient-to-handle ozonizer (7) of this capacity per 100 m.sup.3 of natural water. Ozonization occurs without ozonization reactors and ozone destroyers under pressure directly in the conduit (2) of the natural water stream Q. For this purpose. the ozone air is whirled with a partial stream (q) of the natural water in a flow spiral (9) to form an aerosol-like mixing condition and is blasted into the main stream of natural water. The high phase interfaces thus achieved effect rapid ozonization with quantitative ozone consumption. After the uncomplicated conversion of the baths with original pure chlorination operation to the ozonization-chlorination technique according to the invention, the chemical costs can be reduced by up to 70% with a simultaneous improvement in the water quality.

Abstract: A water treatment system having an apparatus (2) for the intensive pretreatment of the untreated water with ozone, having a downstream filter (3) with reducing action, and also having an apparatus (4) for the post-disinfection is improved in that the excess ozone which accumulates in the upper part (17) of the filter tank and which is added to the water during the pretreatment is removed anhydrously and fed into the apparatus for the post-treatment of the filtered water. The post-treatment takes place preferably in a retention vessel (4) filled with packing material (15) in which the water comes into contact with ozone by surface contact. The water level (24) is kept constant by regulating the gas discharge from the retention vessel (4). (Illustrated by drawing).

Abstract: In the particular embodiments of the waste water treatment system described in the specification, a waste water treatment basin has spaced-apart, moving aerator chains extending across the basin in a direction transverse to the flow of waste water through the basin. When an aerator chain is provided with air, bottom aerators suspended from the chain adjacent to the bottom of the basin move with respect to the basin to mix sludge collected on the basin with the waste water and to supply air to the waste water. A control system supplies air selectively to the aerator chains to provide zones of full aeration and intermediate zones with little or no aeration and the selection of the aerator chains is changed periodically in a progressive manner along the basin so that the zones move progressively through the basin.

Abstract: An arrangement for separation by flocculation of flocculable substances contained in a suspension, as such is used particularly for purifying the backwater of deinking installations for waste paper processing, comprises a container supplied by a conduit with a suspension coming from a reservoir and admixed with flocculating agents and with air. The container contains a rotor with vertical shaft from which two arms extend outwardly at different heights. The suspension to be purified is delivered by the shaft and the upper arm, and by means of the lower situated arm leading the upper arm at an acute angle the purified water is removed. The floated-up flocculated substances are withdrawn from the surface as flotation scum and optionally by means of a conveying device through a scum conduit.

Abstract: A mobile apparatus for chemically decontaminating PCB-contaminated dielectric fluids utilizes three reactors through which the contaminated fluid is processed on a repetitive, sequential batch basis automated by a programmable controller. The processing of each reactor batch includes a charging cycle during which a reactor is filled with contaminated fluid, a reaction cycle during which the PCBs are destroyed by reaction with reagents introduced into a reactor, and a discharging cycle during which the reactor is emptied of decontaminated fluid and reaction by-products into a decanting tank for ultimate separation. The controller coordinates the sequential batch processing through the three reactors in 120.degree. time phased relation such that a charging cycle of one reactor batch, a reaction cycle of a second reactor batch and a discharging cycle of the third reactor batch are all coincident in time during normal operation.

Abstract: A system (10) is provided for treating wastewater discharged from airplane manufacturing operations. The system (10) includes a variety of sequential chemical adjustments to the waste stream which can remove substantially all toxic organics and heavy metals therefrom.

Abstract: A process and apparatus for separating a water emulsion from a hydrocarbon fluid is disclosed. The invention is practiced by conveying the fluids into contact with a metal which has a nickel content greater than seventy-five percent. The invention separates the water from the hydrocarbon fluids and reduces the quantity of paraffin solids which accumulate.

Abstract: Lubricant filter for internal combustion engines, particularly for motor vehicles, of the screwed-on type, both for full flow and bypass filtering, the latter being obtained by superimposed filter cartridges with separation of the flow of filtered lubricant. The filter comprises an incorporated reservoir for reserve additives to be admitted to the lubricant at an appropriate time to reintegrate the original additives which are degraded or exhausted after a certain period of operation. The reservoir communicates with the rest of the filter through a discharge duct, normally closed by an on-off piston valve actuatable by means of an outer control knob, and through a feed hole normally closed by a check valve. When the on-off valve is opened, with the engine idling, the check valve is opened, too, and the reservoir of the additives is brought into communication with the rest of the filter, thus causing mixing of the additives with the lubricant which is fed directly to the oil sump.

Abstract: An apparatus for conditioning stratified water bodies having epilimnion, metalimnion and hypolimnion layers is disclosed comprising a reservoir for containing water so as to define a gas-liquid interface, at least one upwelling conduit adapted for generally vertical disposition within the water body and having an upper discharge end fluidly connected to the reservoir and a plurality of intake ports longitudinally spaced along the conduit so as to afford fluid communication with predetermined depth levels of the epilimnion, metalimnion, and hypolimnion layers of the water body, flow controllers for selectively alternately opening and closing off the intake ports of the upwelling conduit, at least one return conduit adapted for generally vertical disposition within the water body and having an upper inlet end fluidly connected to the reservoir and a plurality of discharge ports longitudinally spaced along the return conduit so as to afford fluid communication with predetermined depth levels of the epilimnion, m

Abstract: A cloudy liquid to be clarified is inserted, after twice receiving flocculation additive, into the bottom of a belt of sludge (4a) in a clarification chamber (4) via a plurality of injectors (22) distributed over the area of said chamber. Uniform distribution of overall flow between these injectors is ensured by internal head loss. The clarified liquid is removed via an upper overflow (4b). Each injector is constituted by a flat cyclone and forms a jet which is highly diverting from its vertical axis in such a manner that the injected flowrate spreads out over an expansion zone belonging to said injector and meeting the expansion zones of adjacent injectors. Further, these jets set up swirling motion which prevents the formation of a layer of sludge having insufficient permeability. The sludge formed in the chamber (4) is directed via a central well (7) towards a secondary clarification stage (3) situated beneath said chamber and supplying both clarified liquid and dense sludge.

Abstract: Chemicals are added to a fluid such as sewage to flocculate and precipitate solids therefrom which are deflected downwardly and sink by gravity to the base of an elongated chamber so that the substantially clarified fluid flows over a weir at one end of the chamber with the flocculated and precipitated material forming a sludge in the base thereof whereafter it may be removed either through a fluid lock device or pressurizing the system to stratify the flow and provide still areas for the sludge to settle through the fluid and be removed as required.

Abstract: Apparatus for purifying water containing material dissolved and/dispersed therein. The apparatus comprises an upflow reactor in which, while maintaining a sludge blanket, the water to be purified can be contacted with one or more agents bringing the dissolved and/or dispersed material into a form in which it can be separated from the water; means for the discharge of the purified water from the apparatus; and an influent distributing system to be connected to a central water supply system. The influent distributing system includes a plurality of tube members assembled to form one or more strings. The strings have outlet openings through which the water to be purified can be introduced into the reactor space at a plurality of spaced locations.

Abstract: This apparatus and method consists of serially or in parallel of contacting a contaminated water countercurrently with air, preferably containing ozone, to remove dissolved organics from the water. It is also desirable to pass the treated water through a carbon adsorbent bed prior to use.

Abstract: A system for dissolution-purification of Zn-containing materials which comprises a dissolving means for dissolving the Zn-containing materials and an ion-exchanging means for separating heavy metal ions included in the solution resulting from the dissolving means. In these means, the liquid or slurry to be treated is subjected to the dissolution and ion-exchanging operation countercurrently and the treatment residue including impurities is separated from the liquid or slurry to be treated so as not to contaminate the liquid or slurry with impurities and to improve the solubility.

Abstract: A mobile water treatment plant capable of handling a high volume of sewage confined within the dimensions of a conventional truck-hauled container comprises:(1) a screen to separate gross solids from liquids;(2) a holding chamber between features 1 and 2 in which the liquid is aerated;(3) a flocculating chamber for the liquid;(4) a lamellar separator (bottom fed with intermediate auxillary lamellae extending 1/2 to 1/3 of the length of the main lamellae); and(5) treatment of the water from the lamellar separator with "activated oxygen" as described and claimed in U.S. Pat. No. 4,214,962.A preferred subsidiary feature is to recycle a controlled amount of the sludge separated at point 1 to the holding tank.

Abstract: A sewage treatment equipment with activated sludge process beds comprising a plurality of treatment tanks arranged in a row, each communicating with an adjacent tank through a passage and being provided with an aeration tank connected with an air in-flow pipe and a plurality of activated sludge process beds disposed vertically above the aeration pipe and in each of which a mesh-like or grid-like outer periphery of a cylindrical core is wrapped with a porous member of a certain thickness and further tightened with tightening belts, characterized in that an outer peripheral area of the cylindrical core is increased tank by tank to give variety to kind of bacteria, bredding ratio between bacterias and distribution thereof.

Abstract: A wastewater treatment apparatus is disclosed in which a rotating biological contactor rotatably mounted on a horizontal shaft is deeply submerged in a wastewater tank, so that a substantial portion of attached biomass does not come into contact with the ambient air. A plurality of gas conduits are disposed in the tank beneath the rotating contactor and are positioned to provide rotational energy to the contactor, to serve as the principal source of oxygen for the submerged biomass and to regulate the rotational velocity of the biological contactor so that the oxygen containing air bubbles are caused to rise into the central region of media rather than being swept along and confined to the outer radius of the media as it rotates.