Control Strategy of Anoxic-Oxic Sequencing Batch Reactor System Using a Specific Feature of Nitrous Oxide Gas

An experimental study was conducted to establish the control strategy of an anoxic-oxic sequencing batch reactor system (AOSBR) using a specific feature of N2O generated during the anoxic and oxic phases. Since NH4+-N, NO2--N and gaseous N2O (GN2O) were found to disappear simultaneously in the oxic phase, the end point of nitrification may be detected from the GN2O profile. It was suggested that the stagflation of nitrification and denitrification could be detected by abnormal GN2O emission in the oxic and anoxic phases. Compared with the conventional indexes of AOSBR, GN2O has several advantages. First, the regulation of GN2O emission could be conducted directly, and second maintenance is easier than conventional indexes because the GN2O monitoring system is more durable than the monitoring system for water quality.