Sequence continuous reaction in complete mix activated sludge systems

A sequence continuous reaction process for consistently removing biochemical oxygen demand, for removing ammonia by nitrification, and for removing both nitrites and nitrates by denitrification from ammonia-contaminated wastewater during both winter and summer temperature conditions, during conditions varying from warm to cold inlet wastewater temperatures, during extreme variations in food supply, and during pronounced variations in biomass concentration and activity by providing capabilities for selectively adjusting the levels of both aerobic dissolved oxygen and anoxic dissolved oxygen and the durations of both aerobic cycles and anoxic cycles of treatment within a single flow-through complete mix activated sludge basin into which said ammonia-contaminated wastewater is fed, said basin being equipped with at least one mixing means, at least one aeration means, dissolved oxygen sensors, and timer controls, which has a hydraulic retention time of a minimum of 6 hours and which contains mixed liquor having a mean cell residence time of at least 6 days, treated mixed liquor from said basin being fed to a clarifying means which produces sludge and clarified liquor, said process comprising:

• A. measuring the carbonaceous biochemical oxygen demand, total Kjeldahl nitrogen, ammonia, nitrate nitrogen, and nitrite nitrogen in said ammonia-contaminated wastewater being fed to said basin;
• B. setting a selected dissolved oxygen level for said mixed liquor during said aerobic cycles within said basin;
• C. setting a selected dissolved oxygen level for said mixed liquor during said anoxic cycles within said basin;
• D. setting a selected length of time for said aerobic cycles within said basin;
• E. setting a selected length of time for said anoxic cycles within said basin;
• F. measuring carbonaceous biochemical oxygen demand, alkalinity, pH, ammonia, nitrate nitrogen, and nitrite nitrogen in said clarified liquor;
• G. adjusting said aerobic dissolved oxygen level and/or said selected set length of time for said aerobic cycles in proportion to said biochemical oxygen demand in said inlet wastewater and in proportion to said nitrate nitrogen and said nitrite nitrogen in said clarified liquor;
• and
• H. adjusting said anoxic dissolved oxygen level and/or said selected set length of time for said anoxic cycles in proportion to said biochemical oxygen demand in said inlet wastewater and in proportion to said nitrate nitrogen and said nitrite nitrogen in said clarified liquor.