Comparison and modeling of two biofilm processes applied to decentralized wastewater treatment

Abstract

In order to control water pollution in the rapidly urbanizing South China area, biological contact oxidation (BCO) process and biological aerated filter (BAF) process were applied in a pilot-scale experiment for decentralized wastewater treatment. An investigation to find the optimal parameters of the two biofilm systems was conducted on hydraulic loading, organic loading, and aeration rate. The results indicated that the water reuse criteria required a maximum hydraulic and organic loading of 30.0 m³/(m²·d) and 4.0 kg COD/(m³·d), respectively, as well as a minimum effluent DO of 4.0 mg/L. The utilization of a new media allowed BAF to perform better than BCO. The kinetic description of the COD removal process for BAF and BCO are , and , respectively. The correlativity analysis showed that the two models could predict the effluent water quality based on the hydraulic retention time. Thus, the appropriate hydraulic loading for certain effluent water quality demands could be determined. The two models could be applied to wastewater treatment practice.

Keywords

biological contact oxidation / biological aerated filter / decentralized wastewater treatment / kinetic model