As water shortages grow increasingly common worldwide, the need to explore decentralized wastewater treatment options to address water pollution has also increased. Electrocoagulation (EC) is a potential technology for decentralized treatment systems due to its convenience and effectiveness. This study investigated the development of a pilot-scale electrocoagulation treatment system to treat source-separated blackwater. Bench-scale EC experiments effectively removed COD, TP, and turbidity. Pulse-width modulation also proved capable of decreasing the energy demand of EC. However, NH3-N was not removed effectively. Bench-scale air stripping experiments revealed that an NH3-N removal efficiency of 67.7% was achievable by increasing the pH of the electrocoagulation-treated blackwater to 11 with calcium hydroxide. In addition, pilot-scale EC experiments showed that utilizing electroflotation with sludge separation units is an essential mechanism for separating solids from the liquid phase of the EC effluent. The pilot-scale study also demonstrated that reducing the distance between electrodes decreases the energy demand of the treatment. Improvements to the pilot-scale EC treatment system decreased the EC reactor's power consumption to 2.64 Wh/L blackwater and reduced the COD, TP, TN, and TSS in the treated water by 90.3%, 98.4%, 85.1%, and 94.8%, respectively. An economic assessment concluded that the treatment system could treat 2,720 L of blackwater per day at a treatment cost of $5.65 per day. A sensitivity analysis showed that a 25% reduction in CapEx could reduce the average treatment cost by 21%, from $5.65/1000 L to $4.50/1000 L.
Read
