Cold Weather Ammonia Reduction in Municipal/Industrial Treatment Plant

Problem

During cold weather this municipal wastewater treatment plant with a high percentage of industrial flow from food processing and electronics manufacturing suffered from high ammonia loadings. As temperatures dropped the plant lost nitrification. The objective of this full-scale product application program was to reestablish ammonia oxidation and reduce ammonia-nitrogen in the lagoon system during cold weather to below the 3 mg/L permit limits.

 MICROCAT^®-XNC Nitrifier Concentrate

Wastewater Flow: 3 MGD (11,363 m³/day) – The wastewater treatment system consists of bar screens and grit chambers, two 15 million gallon (56,818 m³) aerated lagoons in series and two quiescent cells for secondary settling.

Bioscience, Inc. determined that MICROCAT-XNC was to be added to the second aerated lagoon to avoid the possible toxic effects of the high BOD loading from industrial discharges in the first lagoon. MICROCAT-XNC was added continuously to the second aerated lagoon via a chemical pump system. Alkalinity and pH of thesystem were controlled to optimal conditions for nitrification using soda ash. Lagoon temperature ranged from 10-14 degrees Celsius during the inoculation program.

Results (see following chart)

Ammonia-nitrogen removal was 84% during the MICROCAT-XNC addition with an average influent ammonia concentration of 17.4 mg/L, and an average effluent ammonia concentration of 2.8 mg/L. As depicted in the graph, this was significantly better than the two previous years ammonia removal rates of 52% and 43% respectively (both above the permit limit of 3 mg/L). Bioaugmentation with MICROCAT-XNC accomplished the objectives of the program to increase ammonia removal rates and achieve ammonia concentrations below the permit limit.