EMISSION OF NITROUS-OXIDE FROM HIGH-RATE NITRIFICATION AND DENITRIFICATION BY MIXED LIQUOR CIRCULATING PROCESS AND SEQUENCING BATCH REACTORPROCESS

Laboratory scale models simulating a mixed liquor circulating (MLC) pr ocess and a sequencing batch reactor (SBR) process were operated with a high ammonium volumetric loading to study the possible nitrous oxide (N2O) emission from them. The N2O emission from the MLC process was f ound to depend on the DO level in the aerobic reactor. When the DO lev el was high, the emission was negligibly small. The SBR reactor emitte d N2O in a quantity as high as 40 percent of the removed nitrogen. Mos t of the emission occurred during the low DO period in the aeration st age. (C) 1997 IAWQ. Published by Elsevier Science Ltd.