Removal of Refractory Organic Compounds by Single Sludge Predenitrification Process with Pure Oxygen

Abstract

Refractory organic componds are remained even in the effluent of a conventional biological wastewater treatment process which intends to remove mainly BOD₅, and attracts attention in respect to pollution of lakes and bays.
Though a physicochemical treatment process may be applied to remove the refractory organics, it costs a lot for operation and maintenance. It was reported that PVC removal was accomplished by activated sludge process operated at a long SRT (30-50days) . It was also reported that refractory organics and halogenated organic compounds were effectively removed under denitrification conditions.
A long-term experimental study was conducted using a pilot-scale single sludge predenitrification plant, in order to demonstrate the removal performance for refractory organics from municipal wastewater consisting chiefly tannery waste. The data suggest that the refractory organics measured as carbonaceous dissolved COD_Mn was effectively removed by single sludge predenitrification process with pure oxygen. The removal efficiency by the process was 12-16% higher than that by conventional oxygen aeration activated sludge process. The removal efficiency of BOD₅, D-COD_Mn, SS and T-N by the process were 99%, 82%, 98% and 80-85% respectively.