Use of Fly Ash as a Potential Coagulant in the Physico-Chemical Treatment of Domestic Wastewater


Abstract: The effectiveness of fly ash as a coagulant for domestic wastewater treatment was investigated and compared with aluminium sulfate and ferric chloride. In these experiments, four fly ash samples with different chemical compositions obtained from different coal- fired power plants in Turkey were used. In all coagulation-flocculation experiments using fly ash, it was apparent that the predominant removal mechanism varied with the pH and the chemical components of the fly ash. According to our results, the effectiveness of fly ash as a coagulant improves with increasing calcium content. The highest removal efficiency (77% chemical oxygen demand [COD], 73% biochemical oxygen demand [BOD], 98% suspended solid [SS] and 95% turbidity) was attained with fly ash from the Yeniköy Power Plant.

Keywords: Fly ash, Coagulation-flocculation, Domestic wastewater.

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