Performance evaluation of biosimulator for treating domestic wastewater using activated sludge treatment system

Abstract

This research investigation was aimed at demonstrating the performance evaluation of pilot activated sludge treatment system (biosimulator; model MF-114). An intensive analytical program was followed for evaluating the performance efficiency of the biosimulator by maintaining the dissolved oxygen (DO) concentration at 4.0 mg/L throughout the study period. Biosimulator performance was evaluated after every 2 hours and analyzed for pH, DO, COD, ammonia-nitrogen (NH3-N), nitrite-nitrogen (NO2-N) and nitrate-nitrogen (NO3-N). In all ten experimental replicates were performed and the mean figures are taken for discussion. Although no significant variation in the pH was observed during the study period but the mean pH values of the samples during the treatment process gradually increased and it ranged from 6.81-7.52. The removal of COD was found to be in direct relationship with retention time and the mean COD of the raw wastewater samples ranged from 164-1160 mg/L whereas it got
reduced considerably during the treatment process and the mean removal efficiency was found to be 86%. The COD and NO2-N removal efficiency was better than NH3-N and NO3-N this is considered to be satisfactory especially with respect to organic loading and retention time. Similarly, the mean NH3-N values of wastewater after 29 hours of
treatment were found to be fluctuating between 14.52-20.54 mg/L whereas the mean NO3-N level of the raw wastewater ranged from 0.106-0.279 mg/L. The overall conditions were very much favorable even at high organic loading and minimum retention time. It is therefore concluded that the system is practically feasible for the treatment
of wastewater containing high content of organic matter