Method of using wastewater flow equalization basins for multiple biological treatments

The method of utilizing an FEB reactor, having an inflow portion and an outflow portion, to perform multiple biological reactions, in addition to equalizing 2-to-6-day nitrogenous food processing plant wastewater inflow to said FEB reactor to produce uniform 7-day/24-hour outflow, said wastewater having high biological oxygen demand (BOD), comprising the following steps for performing said reactions:

• A) admixing recycled and denitrified mixed liquor with said wastewater within said inflow portion of said FEB reactor;
• B) maintaining anaerobic/anoxic conditions in said mixed liquor within said inflow portion in the absence of nitrites and nitrates to obtain release of energy and phosphate ions by polyP bacteria that hydrolyze adenosine triphosphate (ATP) and form adenosine diphosphate (ADP) while polymerizing a substrate of organic compounds for intracellular storage;
• C) admixing recycled mixed liquor containing nitrite and nitrate ions within said outflow portion;
• and
• D) maintaining anoxic conditions in said mixed liquor within said outflow portion to obtain denitrification of said nitrites and nitrates and release of nitrogen as gas, whereby a portion of said BOD is consumed for performing said reactions.

A method for biological treatment of wastewater, containing proteinaceous materials from an animal slaughtering plant after fat, oil, and grease have been removed from said wastewater, comprising the following steps for multiple biological treatments of said wastewater within a sequence of flow equalization basins that equalize inflow from 2 to 6 days of operation of said plant per week to substantially uniform outflow during 24 hours per day for seven days per week, comprising the following steps:

• A) operating a first flow equalization basin as a first FEB reactor wherein mixed liquor is formed therein and dissolved oxygen therein is controlled to be between anaerobic and anoxic states for hydrolysis of adenosine tripolyphosphate to adenosine diphosphate and liberation of both phosphate ions and energy by polyP bacteria;
• B) operating a second flow equalization basin as a second FEB reactor wherein dissolved oxygen therein is controlled to be at said anoxic state for denitrification of nitrites and nitrates within said mixed liquor to form nitrogen gas;
• C) delivering a remainder portion of said substantially uniform outflow from said second FEB reactor to a nitrification reactor and operating said nitrification reactor under aerobic conditions to nitrify ammonia formed by deamination within said wastewater for producing said nitrites and nitrates and to enable said polyP bacteria to ingest said phosphate ions at a luxury uptake rate while multiplying in numbers, thereby producing nitrite/nitrate liquor;
• and
• D) delivering a recycle portion of said substantially uniform outflow from said second FEB reactor to said first FEB reactor to form mixed liquor therein;
• and
• E) recycling a portion of said nitrite/nitrate liquor from said nitrification reactor to said second FEB reactor.

A method of enabling a flow equalization basin, comprising an inflow half and an outflow half, to be simultaneously utilized as an FEB reactor for flow equalizing, biological release of phosphate ions and intake of volatile fatty acids (VFAs) by polyP bacteria, and selectively limited removal of biological oxygen demand when said inflow half of said FEB reactor is operated on an anaerobic/anoxic basis and when said outflow half is operated on an anoxic/aerobic basis and is followed by an nitrification reactor, comprising the following control steps:

• A) feeding an inflow stream of protein-containing effluent liquor from a food processing plant that is operated on a 2-to-6-day basis to said inflow half of said FEB reactor;
• B) controllably recycling a stream of nitrified mixed liquor containing nitrites and nitrates from said nitrification reactor into a recycle portion and a downstream portion and feeding said recycle portion to said outflow half of said FEB reactor;
• C) controllably dividing an outflow stream of denitrified mixed liquor from said outflow half, said outflow stream being substantially uniform in quantity for 24 hours per day and seven days per week, whereby said flow equalizing is provided, into a recycle portion and a remainder portion;
• and
• D) feeding said recycle portion to said inflow half of said FEB reactor.

In a conventional flow equalization lagoon which equalizes 2-to-6-day inflow to said lagoon of nitrogenous food processing plant wastewater, having high biological oxygen demand (BOD), to produce uniform 7-day/24-hour outflow,

• the improvement that enables multiple biological reactions to be performed therein that consume normal amounts of said BOD and enhance phosphorus and nitrogen removal from said wastewater, comprising the following steps:
• A) dividing said lagoon into two separately mixed portions which operated as a first FEB (Flow Equalization Basin) reactor and a second FEB reactor, said first FEB reactor receiving said inflow and said second FEB reactor receiving outflow from said first FEB reactor;
• B) partially recycling denitrified mixed liquor, as uniform 7-day/24-hour outflow from said second FEB reactor, to said first FEB reactor to produce mixed liquor therein and feeding remaining said outflow to a nitrification reactor that also receives activated sludge from a downstream clarifier;
• C) maintaining said nitrification reactor under aerobic conditions in its supernatant liquor for:
• 1) enabling polyP bacteria in its mixed liquor to multiply, by utilizing a polymerized substrate of organic compounds stored intracellularly, and to ingest phosphate ions on a luxury uptake basis;
• and
• 2) nitrifying ammonia, created by deamination of proteins in said inflow, to produce nitrified mixed liquor that is separated into a recycle stream and a remainder stream, said recycle stream being fed to said second FEB reactor and said remainder stream being fed to an anoxic reactor;
• D) maintaining said first FEB reactor under anaerobic/anoxic conditions in its mixed liquor, whereby said polyP bacteria therein hydrolyze adenosine triphosphate (ATP) and form adenosine diphosphate (ADP) while polymerizing Volatile Fatty Acids (VFAS) to form said substrate of said organic compounds for intracellular storage and releasing said phosphate ions;
• and
• E) maintaining said second FEB reactor under anoxic or anoxic/aerobic conditions in its nixed liquor, whereby nitrates and nitrites in said nitrified mixed liquor are reduced to release nitrogen gas and form said denitrified mixed liquor.