NOVELTY - A flow equalization basin is used to carry multiple biological reactions in the process of performing controlled biological adenosine triphosphate hydrolysis, de-nitrification, and partial reduction of biological oxygen demand. The method is done while simultaneously providing hydraulic flow equalization.    USE - For treating food processing wastewater, particularly for biological treatment of wastewater containing proteinaceous materials from animal slaughtering plant after fat, oil, and grease have been removed from the wastewater.    ADVANTAGE - The improvement enables carrying of multiple biological reactions that consume normal amounts of the BOD and enhance phosphorus and nitrogen removal from the wastewater. The invention reduces the amount of chemical used to precipitate phosphorus is reduced by at least 50%. It consistently achieves 99.2% BOD removal, 99.4% ammonia nitrogen removal, 90% total nitrogen removal, and 94% total phosphorus. The high efficiency total nitrogen removal was achieved without methanol dosage.    DETAILED DESCRIPTION - Use of a flow equalization basin (FEB) (20A, 20B) to perform multiple biological reactions, in addition to equalizing 2-to-6 day nitrogenous food processing plant wastewater inflow to produce a uniform 7-day/24-hour outflow, comprises :    (a) mixing recycled and denitrified mixed liquor with the wastewater within the inflow portion of the FEB reactor;    (b) maintaining anaerobic/anoxic conditions in the mixed liquor in the absence of nitrites and nitrates to obtain release of energy and phosphate ions by polyP bacteria that hydrolyze adenosine triphosphate and form adenosine diphosphate while polymerizing a substrate of organic compounds for intracellular storage;    (c) mixing recycled mixed liquor containing nitrite and nitrate ions within the outflow portion of the FEB reactor; and    (d) maintaining anoxic conditions in the mixed liquor within the outflow portion to obtain denitrification of the nitrites and nitrates and release of nitrogen as gas. A portion of the biological oxygen demand (BOD) of the wastewater is consumed for performing the reactions.    DESCRIPTION OF DRAWING(S) - The figure shows a process flow diagram of a wastewater treatment plant using two FEB reactors.    Flow equalization basin (20A, 20B)