Performance and Factors Evaluation of a Full-scale Biofiltration Process for Wastewater Treatment

The H sewage treatment facility built in 2016 as the main treatment biofiltration (BF) process has encountered difficulties in attaining a sufficient and effluent quality. For this reason, the factors affecting effluent quality were monitored in the present study. Based on suspended solids (SS) analysis, it was found that the stable management of primary sedimentation tank played an important role in ensuring the quality of the effluent water. Polyaluminum chloride (PAC) loadings and the sludge removal rate also found to be key operating factors affecting the effluent water quality. With an increase in turbidity caused by variation in the influent rate, most of the water quality parameters, including SS, total phosphorus, biological oxygen demand, and total organic carbon, proportionally increased in the effluent water. Turbidity was identified as the factor directly influencing the stable operation of the BF process. In a theoretical 100% index operational simulation test, stable nitrification, denitrification, and SS removal rates were achieved. Overall, the most influential factor for the quality of the water discharged from the full-scale sewage treatment plant was found to be the temperature. Continuous monitoring of the BF process to handle changes in the flow rate and water temperature is necessary to ensure a stable water quality. In addition, the activated sludge process exhibited more stable operating characteristics with a biofilter than without one.