Wastewater treatment with enhanced biological phosphorus removal and related purification processes

A biological wastewater treatment system having three interconnected, but separately controlled, systems permitting selection of desired organisms under optimal conditions and efficient utilization of the organisms to effect removal of wastewater constituents from an influent wastewater stream, said system comprising:

• a mainstream biological treatment system including a biological treatment zone for receiving an influent stream of untreated or partially treated wastewater, a downstream solids separation zone for separating effluent from sludge, and means for returning sludge from the solids separation zone to the biological treatment zone as return sludge;
• a first sidestream system in which organisms desired for removal of said constituents are selected under optimal conditions, said first sidestream system being connected to said mainstream sludge returning means to establish an inflow comprising a variably controlled potion of the return sludge, said first sidestream including at least one biological treatment zone receiving the inflow and operable at selected flow rates and retention times to provide means to optimize selection of desired organisms through assimilation of appropriate food materials, and means for returning desired organisms so selected in the first sidestream to the mainstream biological treatment zone;
• and
• a second sidestream system in which food needed for production of the desired organisms is produced, said second sidestream system comprising at least one biological treatment zone connected to establish a variably controlled inflow of liquor from the first sidestream system for flow through the cell under a selected flow rate and retention time conditions to provide means to encourage optimized biological production of organics that satisfy the metabolic needs of the desirable organisms, and means for conveying the organics so produced in the second sidestream to the first sidestream system.

A biological purification system wherein a constituent of an influent stream to be purified is removed by exposure of the stream to desirable organisms, said system having three interconnected, but separately controlled, systems permitting selection of desired organisms under optimal conditions and efficient utilization of the organisms to effect removal of the constituent from the influent stream, said system comprising:

• a mainstream biological treatment system including a biological treatment zone for receiving the influent stream, a solids separation zone for separating effluent from sludge, and means for returning sludge from the solids separation zone to the biological treatment zone as return sludge;
• a first sidestream system in which organisms desired for removal of the constituent are selected under optimal conditions, said first sidestream system being connected to said mainstream sludge returning means to establish an inflow comprising a variably controlled portion of the return sludge, said first sidestream including at least one biological treatment zone receiving the inflow and operable at selected flow rates and retention times to provide means to optimize selection of desired organisms through assimilation of appropriate food materials, and means for returning desired organisms so selected in the first sidestream to the mainstream biological treatment zone;
• a second sidestream system in which food needed for production of the desired organisms is produced, said second sidestream system comprising at least one biological treatment zone connected to establish a variably controlled inflow of liquor from the first sidestream system for flow through the cell under selected flow rate and retention time conditions to provide means to encourage optimized biological production of organics that satisfy the metabolic needs of the desired organisms, and means for conveying the organics so produced in the second sidestream to the first sidestream system.

An activated sludge wastewater treatment process having three interconnected, but separately controlled, processes permitting selection of desired biological phosphorus removal (BPR) organisms under optimal conditions and efficient utilization of the BPR organisms to effect phosphorus removal from an influent wastewater stream, said wastewater treatment process comprising the steps of:

• establishing a mainstream activated sludge wastewater treatment process of the type having an aerobic zone, a solids separation zone and the provision of return activated sludge to the aerobic zone;
• directing a variably controlled portion of the return activated sludge to a first sidestream process where (1) D.O. and NO.sub.x are removed therefrom followed by (2) the selection of desirable BPR organisms through assimilation of volatile acids followed by (3) returning a BPR organism-rich liquor from the first sidestream process to the mainstream process;
• establishing a second sidestream process by directing a variably controlled flow of sludge from the first sidestream to a fermentation zone where fermentation of organic materials occurs over a relatively long retention time to produce volatile acids and other substrates appropriate to satisfy the metabolic needs of the desirable BPR organisms, followed by conveying the volatile acids and other substrates so produced to the first sidestream process;
• operating the three mentioned streams in a hierarchial fashion wherein the flow through the mainstream includes the entire wastewater influent to the plant, the flow through the first sidestream is derived from, is a fraction of and is returned to the mainstream and the flow through the second sidestream is derived from, is a fraction of and is returned to the first sidestream;
• and
• selecting the flow throughputs and retention times for the first and second sidestreams to create optimal conditions for achieving the unique goals of the respective sidestreams.

An activated sludge wastewater treatment process having three interconnected, but separately controlled, processes permitting selection and growth of desired biological phosphorus removal (BPR) organisms under optimal conditions and efficient utilization of the BPR organisms to effect phosphorus removal from an influent wastewater stream, said wastewater treatment process comprising the steps of:

• establishing a mainstream activated sludge wastewater treatment process by (1) introducing untreated or partially-treated wastewater into an aerobic zone where the principal removal of BOD, suspended solids, phosphorus and other wastewater constituents occurs, (2) conveying the contents of the aerobic zone to a solids separation zone where solids separate out from the liquid, (3) removing treated effluent from the solids separation zone and (4) removing sludge from the solids separation zone for return to the aerobic zone as return activated sludge;
• splitting the return activated sludge into two aerobic zone and directing the second flow (Q.sub.1) to a first aerobic zone and directing the second flow (Q.sub.2) to a first sidestream process;
• establishing a first sidestream process by directing the second variably controlled portion (Q.sub.2) of the return activated sludge to an anoxic zone where D.O. and NO.sub.x are removed followed by an anaerobic zone where desirable BPR organisms are selected through assimilation of volatile acids, followed by returning a BPR organism-rich liquor from the anaerobic zone to the mainstream process;
• establishing a second sidestream process by directing a variably controlled flow (Q.sub.3) of anaerobic mixed liquor from the first sidestream anaerobic zone to multiple, serially-connected fermentation cells where fermentation of organic materials occurs over a relatively long retention time to produce volatile acids and other substrates appropriate to satisfy the metabolic needs of the desirable BPR organisms, followed by conveying volatile acids and other substrates so produced in the second sidestream back to the first sidestream process.

An activated sludge wastewater treatment process having three separately controlled processes permitting selection and growth of desired biological phosphorus removal (BPR) organisms under optimal conditions and efficient utilization of the BPR organisms to effect phosphorus removal from an influent wastewater stream, said wastewater treatment process comprising the steps of:

• establishing a mainstream activated sludge wastewater treatment process by (1) introducing untreated or partially-treated wastewater into an aerobic zone where the principal removal of BOD, suspended solids, phosphorus and other wastewater constituents occurs, (2) conveying the contents of the aerobic zone to a solids separation zone where solids separate out from the liquid, (3) removing treated effluent from the solids separation zone and (4) removing sludge from the solids separation zone for return to the aerobic zone as return activated sludge;
• splitting the return activated sludge into two variably controlled flows and directing a first flow (Q.sub.1) to the aerobic zone and directing the second flow (Q.sub.2) to a first sidestream process;
• establishing a first sidestream process by directing the second variably controlled portion (Q.sub.2) of the return activated sludge to an anoxic zone where D.O. and NO.sub.x are removed followed by an anaerobic zone where desirable BPR organisms are selected through assimilation of volatile acids, followed by returning a BPR organism-rich liquor from the anaerobic zone to the mainstream process;
• establishing a second sidestream process by directing a variably controlled flow of fermentation material to at least one fermentation cell where fermentation of organic materials occurs over a relatively long retention time to produce volatile acids and other substrates appropriate to satisfy the metabolic needs of the desirable BPR organisms, followed by conveying volatile acids and other substrates so produced in the second sidestream back to the anaerobic zone of the first sidestream process.