Use of Converter Slag-Coal Cinder Filters for Phosphate Removal

Mixing converter slag and coal cinder as substrates of filters for phosphorous removal from domestic wastewater was studied in the column experiments. Three converter slag-coal cinder filter columns: Column 1# (V_{converter slag}:V_{coal cinder} =1:1.5), Column 2#(V_{converter slag}:V_{coal cinder} =1:3) , Column 3#(V_{converter slag}:V_{coal cinder} =1:5) were operated for more than one month, and the average influent and effluents total phosphorus (TP) concentrations were 2.24 plusmn 0.52 mg/L, 0.66 plusmn 0.23 mg/L, 0.96 plusmn 0.28 mg/L and 0.59 plusmn 0.23 mg/L, respectively. After three months, slag samples were taken from the columns and P-extraction experiments were performed to elucidate the dominant P-retention mechanisms. Main reasons for P-retention were the Fe-bounded and Ca-bounded P. This study indicated the potential use of the converter slag-coal cinder filter with higher P-removal capacity for secondary and tertiary treatment, and the material ratio of converter slag to coal cinder was an important parameter for the system.