Optimization of Sequencing Batch Reactor Operating Conditions for Treatment of High-Strength Pharmaceutical Wastewater

Optimization of Sequencing Batch Reactor (SBR) operating conditions for treatment of high-strength non-penicillin pharmaceutical wastewater is a challenging task. Two SBR were operated under different operating conditions. Three different Hydraulic Retention Times (HRT) (12, 24 and 48 h) were tested and operatd under high (6000 mg/L) and low (4000 mg/L) Mixed Liquor Suspended Solids (MLSS) concentration. Statistical analysis (two-way ANOVA) using SPSS software was applied on the results to evaluate the effects of HRT and MLSS concentration on the SBR performance. The hydraulic retention time of 24 h was found suitable for the SBR and increasing HRT from 12 to 24 h significantly affected the BOD5 removal; however, increasing HRT from 24 to 48 h or inceasing MLSS concentration from 4000 to 6000 mg/L did not significantly improve the SBR performance in terms of BOD5 removal. Under the optimum operating conditions (HRT 24 h and MLSS concentration 4000 mg/L), the SBR achieved an efficiency of 94±1.3% in terms of BOD5 removal and 83.9±1.7% in terms of COD removal, with complete nitrification.