Pragmatic Nitrification Inhibition Testing for Robust Plant Design

Three cases where nitrification rate testing was conducted to assess nitrification inhibition issues at municipal wastewater treatment plants are presented. The testing methods used were specific nitrification rate (SNR) batch tests and the WERF Low F/M protocol (WERF, 2003). In the first case SNR testing was used to locate the source of an intermittent industrial input causing a temporary complete loss of nitrification in a municipal treatment plant. In the second case, SNR testing was used to assess the impact of a known industrial input to one train of a municipal wastewater treatment plant. In the third case, the Low F/M protocol was extended to include long-term oxygen utilization rate monitoring to screen a plant's influent for potential transient inhibition.