Feasibility Study on Biological Nutrient Removal in Sequencing Batch Reactor Treating Municipal Wastewater

This study elucidates the performance of sequencing batch reactor for nutrient removal from municipal wastewater. The removal of COD, ammonia nitrogen and phosphorus were investigated. The SBR with a working volume of 5 L was operated for 6 hours, with 5 min fill, 30 min settle and 5 min effluent withdrawal. The remaining time in each cycle was 90 min anaerobic phase, 130 min anoxic phase and 110 min aerobic phase. The experiment was repeated with a longer aeration time of 180 min resulting to prolong the duration cycle. In the aerobic phase, dissolved oxygen was kept in the range of more than 2 mg/L. During batch operation, the system attained stability and had a removal efficiency for ammonia nitrogen, COD and phosphorus of 51.36%, 83.33% and 99.53%, respectively. Extending the aeration period improved ammonia nitrogen removal to 54.27%. It should be noted that the stability of the granular biomass agglomerates highly depending on the bacterial consortia. The particle size of sludge reduced from 60.26 μm to 39.00 μm in 60 days. It was observed that degranulation process and biomass loss was unavoidable.