Treatment of High-Strength Domestic Wastewater in Anaerobic, Aerobic and Anoxic Fed-Batch Process System

For treatment of high-strength domestic wastewater, this study explores a fed-batch bioprocess system consisting of anaerobic (AD), aerobic (AER) and anoxic (ANX) processes in this order and each run at 24 h hydraulic retention time (HRT) and 0.8 g COD/L/d in the first bioreactor. The largest COD removal occurred in the anaerobic process, followed by the aerobic process. The overall removal in the last 6 cycles with three bioprocesses in series, was 1,222.19± 213.14 mg/L or average 83.82 ± 9.73% based on influent levels. Of this COD removed, 546.15 ± 102.00 mg/L (ca. 38%) was removed in the AD, while 541.37± 227.13 (ca. 37%) was removed in the aerobic bioreactor. Biogas production accounts for 64.48±27.83% of the COD removed in the AD process. Much of the ammonia-N removal occurred in the aerobic bioreactor (84.08 ± 18.95% of the influent NH3-N to the aerobic bioreactor). The amount (mg/L) of nitrate-N removed in the ANX process via denitrification is 36.0 ± 33.6 mg/L, which is 63.0 ± 30.4% of influent nitrate-N to the anoxic bioreactor.