PERFORMANCE OF INTEGRATED TWO STAGE ANOXIC-AEROBIC SEQUENCING BATCH REACTOR IN THE TREATMENT OF SEWAGE

Abstract

A 10 L SBR reactor was operated on a two cycles per day with total cycle time of 500 minutes. This study explored the impact of a 300 minute react period with alternating two stage anoxic-aerobic phases starting at 120 minutes to 30 minutes on effluent quality, sludge settleability and particle size distribution.The overall removal efficiencies for COD,  TSS and NH4-N were 93.8%, 98.4 % and 85.9%, respectively. The results indicated a good process performance with the first 2h anoxic/1.5 h aerobic period with removals of 66.0%, 78.5% and 59.4 % for COD, NH4-N and TSS removal respectively.The NH4-N removal was not enhanced although the anoxic period was lengthened by 1 h with low removal of 4.5 % and subsequent 7.2% of the second aerobic phase. There was an increase in the particle size of the sludge from 117.743μm to 127.310μm over an  operating period of 35 days.