Patent ID: 6562237
Filing Date: 2003-05-13
Classification: C02F,Y10S

Abstract:
A biological process for the removal of nitrogen and phosphorus from municipal or industrial waste water, comprising the steps of,a) conducting an incoming flow of waste water to a balancing tank, for balancing the flow of liquor to a subsequent stage of the process, b) causing fermentation of said waste water in said balancing tank, c) controlling the flow of liquor from said balancing tank at a rate such that a first, anoxic, zone and a second, anaerobic, zone of fermentation is established in said balancing tank for denitrification and removal of phosphorus from liquor fermented therein d) conducting liquor flowing from said balancing tank to an aerobic zone, for oxidation and nitrification of components of the liquor, e) recirculating nitrified mixed liquor from said aerobic zone to said anoxic zone at a flow rate selected to meet a desired state of fermentation of the liquor within said balancing tank, and f) adjusting the flow of liquor from said balancing tank to compensate for the rate of recirculation of liquor from said aerobic zone to said anoxic zone.