Treatment of surfactant-stabilized oily wastewater using coalescing bed of bagasse fly ash (BFA) as a low-cost filter medium: modelling and optimization of process parameters

Abstract

In the present study, surfactant-stabilized oily wastewater was separated using a low-cost agricultural waste, bagasse fly ash (BFA) in a packed coalescing bed. Factors such as pH (A), BFA bed height (B) and flow rate of emulsion (C) were the most significant process parameters, affecting the oil separation efficiency by the BFA coalescing bed. The effect of the above parameters on the removal efficiency of BFA coalescing bed was investigated by three-level-three-factor (3³) Box–Behnken Design model using response surface methodology. A second-order polynomial model equation was proposed with a high correlation coefficient (R² = 0.9942), which explained the parametric interactions significantly well. About 84.8% of oil removal efficiency was achieved under optimal parametric conditions: pH₀ 3, 100 mm bed height and 0.145 dm³/min flow rate. BFA, being almost a free waste material, can be effectively used for the treatment of oily wastewaters.

Keywords:

• Wastewater treatment
• Oily wastewater
• Bagasse fly ash (BFA)
• Low-cost filter media
• Oil removal
• Optimization

Acknowledgement

The authors thank Uttam Sugar Mills Ltd. for providing the BFA free of cost for the research study. The financial support provided to one of the authors (P.K.) by the Ministry of Human Resource Development (MHRD), Government of India, during the present research work is gratefully acknowledged.