Aerated and unaerated steel slag filter systems as polishing unit for phosphorus removal from textile industrial effluent

Abstract Improper tertiary treatment of industrial effluent discharged causes an excessive phosphorus input which leads to eutrophication. Excessive growth of algae will degrade the natural ecosystem of surface waters. Conventional treatment such as activated carbon filter used as a polishing unit in the tertiary treatment is unable to eliminate the phosphorus completely. Approximately, 0.3–15 mg/l of phosphorus still presents in the final discharge of industrial effluent. Therefore, this study is conducted to provide alternative solutions using natural treatment with cost saving materials to further remove phosphorus from the textile industrial effluent. Aerated and unaerated lab-scale steel slag filters systems were run for 12 weeks at water treatment plant. The sample collected was analyzed twice a week for the parameters of pH, alkalinity, temperature, dissolved oxygen, total phosphorus, chemical oxygen demand, and total suspended solid. The results of this study showed that the unaerated steel slag filter (USSF) has a high percentage of phosphorus removal compared to aerated steel slag filter (ASSF) which is 55% to 86% while ASSF have removal efficiency of 52% to 71%. However, the removal efficiency of activated carbon filter (ACF) used in treatment plant is slightly better than ASSF which is 52% to 81%. The mechanism of removal involved is likely to be through adsorption.