Response surface methodology approach for simultaneous carbon, nitrogen, and phosphorus removal from industrial wastewater in a sequencing batch reactor

Wastewater reclamation involving a sequencing batch reactor (SBR) has received more attention recently due to its high nutrient removal efficiency, cost-effectiveness, and low footprint. This study attempts to develop a stable and applicable activated sludge SBR for simultaneous carbon and nutrient removal from industrial wastewater. The derived-filed data were explored by response surface methodology (RSM) to identify the impact of operational variables on the SBR performance. Optimum conditions were obtained at ۴۰۰۰ mg/L MLSS, ۱۰۰: ۸: ۲ COD: N: P ratio, ۴۰ min/h aeration time, and ۴۰ h cycling time, which resulted in the removal of ۸۲.۵۳% chemical oxygen demand (COD), ۸۹.۸۳% TKN, ۸۷.۲۳% PO۴۳--P, and ۷۳.۴۶% NO۳--N. Moreover, the sludge volume index (SVI) and mixed liquor volatile suspended solids (MLVSS)/mixed liquor suspended solids (MLSS) ratio were ۶۴.۸ mL/g and ۰.۸, respectively. The maximum nitrification rate was calculated as ۱۱۳.۹ mg/L.d, which increased with the rise of the initial ammonium concentration. The specific denitrification rate (SDNR) was estimated in the range of ۰.۰۰۳-۰.۰۷ mgNO۳--N/mg MLVSS.d, depicting the high potential of the SBR reactor to eliminate nitrate by granular sludge. Accordingly, the removal efficiency of the optimized system revealed a notable capability towards meeting environmental regulations. 

Keywords:

Wastewater treatment , Response surface methodology , Granular sludge , SDNR