Treatment of a Shopping Mall Wastewater Using an Attached Growth Anoxic-Aerobic System

An integrated water quality management system involves both treatment of wastewater and appropriate reuse of the effluent. Treated wastewater from commercial establishments such as hotels, high-rise residential or office buildings and shopping malls are potential source of non-potable water for use as landscape watering and toilet flushing. This study aimed to determine the performance of a full-scale aerobic activated sludge system and a bench-scale attached growth anoxic-aerobic growth wastewater treatment system (WWTS) which operated at shorter HIRT and higher organic loading rate (OLR) than the present full-scale system. The effect of HRT on the bench-scale performance was also determined. Furthermore, it assessed the effluent water quality for possible reuse. In the full-scale WWTS, at 2.06 +/- 0.18 days HRT and 0.396 +/- 0.123 kg COD/OLR, the COD, BOD, FOG and TSS removal efficiency were 97.2 +/- 2.3%, 95.3 +/- 2.0%, 91.6 +/- 15.0% and 85.96 +/- 13.4%, respectively. In the bench-scale attached growth anaerobic-aerobic WWTS, the BOD, COD, FOG and TSS removal efficiency were 97.9 +/- 2.3%, 93.6 +/- 5.9%, 87.8 +/- 22.9% and 71.4 +/- 18.5%, respectively, at 6.35 h HRT and 2.42 +/- 0.40 kg COD/OLR. The efficiencies were better at longer HRT and lower OLR. At 12.70 h HRT and 1.50 +/- 0.30 kg COD/OLR, the BOD, COD, FOG and TSS removal efficiencies were 98.1 +/- 2.4%, 94.7 +/- 4.6%, 95.0 +/- 5.1% and 91.4 +/- 2.4%, respectively. The effluent of the bench-scale WWTS after an additional tertiary treatment could be used for landscape watering and flushing toilet.