(613b) A Combined Electrocoagulation and Electrodialysis Process for Decentralized Treatment of High-Strength Wastewater While Harvesting Ammonia

Water scarcity is an ever-increasing problem which is especially prevalent in decentralized and rural areas. New technologies must be developed to treat the wastewater in these locations and to avoid water pollution and maximize the available water supply. Due to the decentralized nature of these locations, traditional wastewater treatment techniques are suboptimal due to high capital and transportation costs. A combined electrocoagulation and electrodialysis system can be a good solution to treat wastewater. This study investigated the development of the combination of electrocoagulation (EC) and electrodialysis (ED) as a water treatment and resource recovery technique for source-separated high-strength wastewater - blackwater. Bench-scale EC experiments effectively removed COD, TP, and turbidity. A pilot scale EC reactor utilizing electroflotation with sludge separation units was designed to achieve 1.5 L/min throughput with an energy consumption of 2.64 Wh/L blackwater and reduced the COD, TP, and TSS in the treated water by 90.35, 98.4%, 94.8% respectively. However, NH₃-N was not removed effectively making it an ideal treatment before ED. Therefore, bench scale ED experiments were conducted to test the viability and effectiveness of ammonia concentration from synthetic wastewater. The ammonia concentration was shown to be able to reach concentrations of 7.95 g/L NH₃-N with a relatively low energy consumption of 1.32 Wh/L. The results demonstrate a simple, effective, and robust solution to treat and utilize high-strength wastewater with a relatively low energy demand.