Abstract: An activated sludge process for the treatment of municipal wastewater, particularly applicable to oxidation ditch activated sludge treatment systems which utilize a conventional race track or continuous loop reactor basin configuration. The process removes phosphorus and nitrogen from an activated sludge wastewater treatment system, with an anoxic cycle followed by an aerobic cycle, and followed by a surface wasting cycle until a low flow diurnal period is reached in a diurnal or twenty-four hour period. Automated microprocessor control system using “oxidation-reduction potential” (ORP) and “dissolved oxygen” (DO) as process variable inputs automate aerated and anoxic cycles to optimize phosphorus and nitrogen removal using the available carbon in the influent wastewater resulting in an energy efficient dynamic dissolved oxygen control during the aerated periods.

Abstract: A wastewater treatment method applicable to new or existing enhanced biological phosphorus removal (EBPR) treatment process designs which utilize the sequencing batch reactor (SBR) process activated sludge process treatment tanks. The method improves the performance and efficiency in the treatment of municipal and industrial wastewater to remove phosphorus (P) and nitrogen (N). The method includes ceasing reaction cycles when a derivative of rate of change of the input flow volume of the air stream into the tank needed to maintain a low-range of dissolved oxygen (DO), in which an oxidation reduction potential (ORP) setpoint reaches a derivative value indicating that conversion of the ammonia nitrogen in the influent wastewater content to a nitrite or to a nitrate is complete.