Abstract: Wastewater treatment tank for achieving hydraulic flow equalization and high efficiency soluble biological oxygen demand (BOD) removal. The wastewater treatment tank provides a compact arrangement of at least one dissolved air flotation (DAF) cell and an equalization reactor cell. The tank achieves regulatory wastewater pretreatment requirements for reducing total BOD concentrations below 250 to 300 mg/L.

Abstract: An anaerobic lagoon wastewater treatment system, which includes a plurality of wastewater treatment zones. The treatment zones are either formed by providing a plurality of separate lagoons or by providing one or more partitioning elements within one lagoon. One or more treatment zones may also be provided in the form of an anaerobic tank. The first wastewater treatment zone in the direction of wastewater flow has a smaller volume than the second wastewater treatment zone. Further, the first wastewater treatment zone achieves a significant reduction in fat, oil and grease removal, as well as in total suspended solids removal, but only a modest reduction in biological oxygen demand. An effluent from the first wastewater treatment zone is mixed with an effluent from the second wastewater treatment zone such that a predetermined ratio of carbon to nitrogen is maintained within the mixture of first and second effluents.

Abstract: An upflow continuous backwash deep bed sand filter (UCBF) having a recycle line for returning carbonaceous denitrifying bacteria attached to biomass to the influent of the UCBF. The recycle line returns the biomass to the treatment process at a location upstream of the upflow continuous backwash filter. Further, a liquid level control unit is provided that reduces fluctuations and significant drop in the liquid level upstream of the upflow continuous backwash filter, thereby avoiding or minimizing flow turbulences, air induction, and undesirable wastewater aeration resulting in the need to dose excessive carbon source to remove dissolved oxygen in the aerated wastewater.

Abstract: Method for treating wastewater, in particular municipal wastewater, in which the wastewater is initially received in an equalization basin reactor for performing an infiltration and inflow equalization process. The equalization basin reactor has sufficient capacity for the increased inflow of wastewater received under wet weather conditions. However, the increased inflow is not merely stored in the equalization basin reactor for later processing, but the wastewater treatment process continues throughout the wet weather period with the first stage wastewater treatment being performed in the equalization basin reactor, which further provides a substantially constant outflow of partially treated wastewater for subsequent treatment stages.

Abstract: An anaerobic lagoon wastewater treatment system, which includes a plurality of wastewater treatment zones. The treatment zones are either formed by providing a plurality of separate lagoons or by providing one or more partitioning elements within one lagoon. One or more treatment zones may also be provided in the form of a tank. The first wastewater treatment zone in the direction of wastewater flow has a smaller volume than the second wastewater treatment zone. Further, the first wastewater treatment zone achieves a significant reduction in fat, oil and grease removal, as well as in total suspended solids removal, but only a modest reduction in biological oxygen demand. An effluent from the first wastewater treatment zone is mixed with an effluent from the second wastewater treatment zone such that a predetermined ratio of carbon to nitrogen is maintained within the mixture of first and second effluents.

Abstract: An anaerobic lagoon wastewater treatment system has a flow-splitter tank for accurately dividing a flow of raw, untreated wastewater. The system is designed as an earthen basin or as a tank and includes at least one partitioning element for providing two connected wastewater treatment zones. The first wastewater treatment zone in the direction of wastewater flow has a larger volume and is more efficient in the removal of biological oxygen demand (BOD) than the second wastewater treatment zone. The flow-splitter tank divides the incoming wastewater flow into two streams, which are conducted to the first and second wastewater treatment zones, respectively. A predetermined ratio of carbon to nitrogen is maintained within an effluent pumped from the second wastewater treatment zone by adjusting the relative amount of raw wastewater added directly to the second wastewater treatment zone.

Abstract: Wastewater treatment tank for achieving hydraulic flow equalization and high efficiency soluble biological oxygen demand (BOD) removal. The wastewater treatment tank provides a compact arrangement of at least one dissolved air flotation (DAF) cell and an equalization reactor cell. The tank achieves regulatory wastewater pretreatment requirements for reducing total BOD concentrations below 250 to 300 mg/L.

Abstract: Spray apparatus including an air heater and mixer for mixing a liquid, typically a disinfectant or a cleaning agent, into the air stream created by the air heater. The spray apparatus can be provided on a carrier back frame or on a cart.

Abstract: Method for treating wastewater, in particular municipal wastewater, in which the wastewater is initially received in an equalization basin reactor for performing an infiltration and inflow equalization process. The equalization basin reactor has sufficient capacity for the increased inflow of wastewater received under wet weather conditions. However, the increased inflow is not merely stored in the equalization basin reactor for later processing, but the wastewater treatment process continues throughout the wet weather period with the first stage wastewater treatment being performed in the equalization basin reactor, which further provides a substantially constant outflow of partially treated wastewater for subsequent treatment stages.

Abstract: A process that removes nitrogen by the MLE Process or nitrogen and phosphorus by the Bio-P Process from municipal or industrial wastewaters by combining at least one dual-use jet recirculation pump with jet manifolds disposed at the bottoms of deep tanks functioning as Reactors to withdraw mixed liquor from a flow-connected tank and mixed liquor from a downstream tank in selected amounts, both mixed liquors being pumped to the jet manifold within the flow-connected tank that mixes the contents of the tank, whereby higher operating costs for electric power and higher capital costs for larger pumps and piping are avoided.

Abstract: One or more flow equalization basins or lagoons are utilized for performing hydrolysis of ATP as the first stage of biological phosphorus reduction, selective reduction of biological oxygen demand (BOD), deamination, and denitrification of nitrate and nitrite compounds, in addition to simultaneous flow equalization of wastewater produced by food processing operations on a 2-to-6-day schedule. The inflow half of a single basin or an entire first basin is. operated on an anaerobic/anoxic basis. The outflow half of the single basin or an entire second basin, if present, is operated on an anoxic/aerobic basis. A downstream nitrification reactor is operated on an aerobic/anoxic basis or is operated exclusively on an aerobic basis if followed by an anoxic reactor.

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 process and any of several pump/circulators provide selective rapid mixing of influent wastewater with the mixed liquor in the channel of an oxidation ditch and thereby provide maximized use of the entire volume of the channel. The pump/circulator is disposed at the beginning of the anoxic zone and preferably receives the influent wastewater. The oxidation ditch is preferably a barrier oxidation ditch or at least a baffle oxidation ditch in order to prevent backmixing.

Abstract: A process is disclosed for treating food wastewaters by acidifying to a low pH, adding an alginate, and, preferably, adding lime to a pH of at least 7.0, without adding iron or aluminum to assist in coagulation and flocculation of the wastewater. A floc is formed at acid pH in some wastewaters and at neutral to alkaline pH in other wastewaters treated with lime. After recovery of the floc as a sludge, the process provides at least about 70% removals of Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD), and Chemical Oxygen Demand (COD) at reasonable costs and with negligible formation of free fatty acids in the resulting sludge.

Abstract: A nitrification-denitrification process is disclosed wherein a single flow-through and cyclically operated complete mix activated sludge basin, containing mixed liquor having a mean cell residence time of at least 15 days, is fed with wastewater and discharges treated wastewater to a clarifier while its contents are continuously agitated and cyclically aerated for approximately 3-9 minutes to form an oxic stage and then not aerated for approximately 3-9 minutes to form an anoxic stage. The treated and clarified liquor has ammonia contents no higher than 2.0 mg/l, nitrite contents no higher than 1.0 mg/l, and nitrate contents no higher than 2.0 mg/l. Approximately 99.9% by weight of the discharged sludge from the clarifier is returned to the complete mix basin, the remainder being waste activated sludge.

Abstract: For use in an activated sludge process, dual-baffle aerators for both vertically mounted surface aerators and static mixer-aerators are disclosed. These devices substantially prevent back-mixing of freshly aerated liquor into aerator intakes and provide directional propulsion. By connecting two or more such devices to form a barrier across the channel of an oxidation ditch, homogeneous aeration is provided to the mixed liquor. Barriered pump/aerator assemblies utilizing directional mix jet aerators (eddy jet) are also described. These devices can also be combined with dual-baffle aerators to furnish both propulsion and a selected degree of homogeneous aeration in a barrier oxidation ditch. An adjustably apertured barriered pump assembly is additionally disclosed for providing a selected balance between homogeneous aeration and/or mixing and heterogeneous aeration and/or mixing.

Abstract: A process is described for treating a feed wastewater from a food preparation plant to recover substantially all of its fats and up to 50% of its proteins in a chemical float sludge which is selectively admixed with an absorptive bulking agent, such as sawdust, at a dry-basis weight ratio of 3-4 pounds of bulking agent to one pound of total sludge solids to produce a biomass mixture which is selectively dried and regulated in size to a maximum of 1/8-inch to produce a biomass fuel, characterized by a fuel value of approximately 11,000 Btu per pound, which is highly suitable for self-sustained burning in a gasifier-type suspension burner. After removal of the float sludge, the partially purified wastewater is aerobically treated with microorganisms to produce activated sludge, a selected portion thereof being recycled to the feed wastewater before admixing coagulation and flocculation chemicals therewith.

Abstract: A jet aerator header assembly is provided for the deep oxygen contact duct of a partial, total, or non-barriered oxidation ditch having an endless channel. The header assembly may be vertically installed in the bottom of the contact duct or at an angle in the intake portion thereof as a mid-duct header assembly; it can additionally be installed in a horizontal position at the inlet of the contact duct as an inlet header assembly. Each header assembly comprises a liquid header, an air header, a plurality of jet aerators which are flow connected to both headers, stiffener plates which rigidly attach the headers to each other and to the jet aerators, and pipes connecting the headers to respective liquid and air supply lines. The mid-duct header assembly is slideably mounted within an access duct which is accessible from the surface.

Abstract: A process is described for producing an animal feed, comparable to feathermeal in properties and appearance, from two waste products: float sludge and activated sludge. The process uses a bulking agent for extracting excess fat from the sludges, particularly the float sludge, while a mixture of the sludges and the bulking agent is being stirred, heated, and dried. Blood, chicken litter, meat scrap, and the like can be substituted for activated sludge to provide protein. The bulking agent can be any material that can expose the sludges to air, that is capable of absorbing fat, and that can be separated from the dried and partially de-fatted sludges. Wood chips are the preferred bulking agent. Wood shavings, shredded cardboard, shredded newspaper, paunch manure, and the like can be substituted for wood chips as the bulking agent.

Abstract: An improved barrier oxidation ditch is provided which has a channel portion for unaerated induced-flow and an inclined duct for aerated induced flow, whereby energy in the dammed-up momentum is more efficiently released. This induced-flow duct is inclided at 30.degree. to 60.degree. to the horizontal, preferably 45.degree., and is disposed upstream of, downstream of, or alongside of the circulator/aerator in the intake channel. The induced-flow duct is preferably rectangular in cross-section and may have its downstream wall formed by the baffle if it is downstream of the circulator/aerator. The induced-flow duct is connected at its lower end to the discharge duct to initiate a combined-flow portion thereof. This combined-flow portion has an upper side which may be a thin wall or may be a much thicker aerator bridge. A baffle may be mounted downstream of the inlet of the induced flow duct for selectively restricting the amount of unaerated induced flow.