Method and apparatus for nitrogen removal in wastewater treatment

摘要

One or more reactor and one or more control methods are used for nitrogen removal in wastewater treatment to achieve measured control of maintaining high ammonia oxidizing bacteria (AOB) oxidation rates while achieving nitrite oxidizing bacteria (NOB) out-selection, using various control strategies, including: 1) ammonia and the use of ammonia setpoints; 2) operational DO and the use of DO setpoints; 3) bioaugmentation of anammox and lighter flocculant AOB fraction; and 4) implementation of transient anoxia in several reactor configurations and conditions for removal of oxidized nitrogen using anammox or heterotrophic organisms. Controls described maximize nitrogen removal with minimal aeration, through control of transient anoxia and aerobic SRT, out-selection of NOB, and control of DO concentrations or aeration interval by keeping the reactor ammonia (NH4) and oxidized nitrogen (NOx) concentrations approximately equal, and maximize total inorganic nitrogen (TIN) removal through nitrification, limited nitritation, nitritation, denitrification, denitritation or deammonification making use of the aforementioned strategies.

主权项

1. A wastewater treatment apparatus, comprising:
a biological nitrogen removal (BNR) reactor having a volume that is transiently aerated; an ammonia sensor for generating an ammonia concentration signal; and a controller for processing the ammonia concentration signal and for thereby causing out-selection of nitrite oxidizing bacteria (NOB) under controlled transient anoxia conditions, the conditions being controlled either along the flow-path or along the process time-line, and wherein the apparatus is configured to cause a dissolved oxygen (DO) profile to switch between a lower DO setpoint of less than 0.1 mg/L and an upper DO setpoint of greater than 1.0 mg/L, and wherein an aeration system activation interval, the upper DO setpoint, or both are set such that an on-line measured ammonia concentration is higher than 1.5 mg/L ammonia as nitrogen, for more than 75% of the transiently-aerated reactor volume in space or time.