Aerobic sequential batch reactor for domestic sewage treatment: parametric optimization and kinetics studies

Domestic sewage (DS) was first treated in aerobic sequential batch reactor (SBR). In order to increase the treated water quality, DS from SBR was further treated using electrocoagulation (EC) and Ion exchange (IE) process. In the SBR study, process parameters such as hydraulic retention time (HRT) and reactor fill time ( t f ) was optimized at various volume exchange ratio (VER) of 0.534, 0.4, 0.266, and 0.133. The best HRT and t f were observed to be 0.78 day (d) and 2 h, respectively, providing 72.37% chemical oxygen demand (COD) reduction (initial value of COD = 270 mg/dm 3 ). Kinetics of biodegradation in SBR was also studied. The second stage treatment was performed in EC reactor at 1 ampere (A) current for 30 min electrolysis time ( t R ). EC reactor, further reduced COD and biological oxygen demand (BOD) up to 72 and 21 mg/dm 3 from its average initial COD and BOD of 94 and 23 mg/dm 3 , respectively. Second stage treatment in IE process reduced hardness, sulphate, and phosphate up to 15, 0.05, and 0.13 mg/dm 3 from its initial value 350, 5.48 and 1.16 mg/dm 3 , respectively. The treated water can be used as potable water after disinfection as its water quality is near to river water.