Improving Stormwater Runoff Quality using Wasted activated Carbon from a Household Water Purifier

Abstract

Objectives : To recycle the wasted activated carbon from water purifiers and reuse stormwater runoff, this study evaluated water quality of stormwater runoff with regeneration using granular activated carbon containing commercial activated carbon for water treatment and wasted activated carbon from household water purifiers.Methods : The removal of total coliforms, chloride, BOD, T-N, T-P, turbidity, and pH in stormwater runoff were analyzed by down-flow column test using granular activated carbon with varied mixing ratios. In addition, chemical modification with ferrous sulfate and ultrasonic treatment were conducted to improve the removal efficiency of total coliforms, and turbidity.Results and Discussion : The optimal mixing ratio of granular activated carbon was 7:3 (GAC:WGAC), which showed high removal efficiency of 88.2% for total coliforms, 70.8% for chloride, 72.6% for BOD, 88.4% for T-N, 50.7% for T-P, and 85.9% for turbidity. The granular activated carbon with surface modification using a 0.2 M FeSO<sub>4</sub> solution with ultrasonic treatment demonstrated the highest removal efficiency, with a reduction of 11.8% in total coliforms, 29.2% in chloride, 12.1% in BOD, 20.3% in T-P, and 13.2% in turbidity, while T-N showed a decrease of 19.4% in removal efficiency.Conclusion : The granular activated carbon with a 7:3 mixing ratio showed highest removal efficiencies for all water quality parameters, while the total coliforms and turbidity did not meet the water quality standards for reclaimed water. This indicated that further physicochemical surface modification with FeSO<sub>4</sub> and ultrasonic treatment was needed to improve the removal performance and meet the water quality standards for reclaimed water. This approach explored in this study using wasted activated carbon should be continued in the area of resource and water circulation to properly utilize resources of wastes.