Renewable Energy Production and Saline Water Desalination from municipal Wastewater Using Bio-Electrochemical Processes

Background and Microbial desalination cells are the new technologies that can be used for wastewater treatment, desalination of seawater and electricity production simultaneously.
This experimental study was performed on a laboratory scale as a batch mode. The anode was flat carbon graphite that were heat treated, and the cathode was carbon cloth with 0.5 mg/cm2 of Pt on the water side and four PTFE diffusion layers on the air side. Output voltage was measured and power and current density were calculated. Changes in pH, COD, EC and chloride in the solution of the reactor vessel were evaluated and based on these changes, the parameters such as efficiency in COD reducing, the rate reduction of EC of salt-water and COD of wastewater and then columbic efficiency were calculated.
About half of EC in saltwater was reduced. Change percent in chloride ion in 25, 50 mM PBS and municipal wastewater was 175±21, 217±2 and 311±53 respectively. COD removal efficiency in 25, 50 mM PBS and municipal wastewater was 86±1, 80± 1and 76±4 mg / L, and the rate of COD removal was 10.74 ± 0.62, 6.95 ± 0.74 and 6.77 ± 0.25 mg / L.hr respectively. Columbic efficiency in 25, 50 mM PBS and municipal wastewater was 24±2, 51± 3and 25±0 respectively.
Due to the significant reduction in COD and about half of the EC in wastewater, this technology can be used for municipal wastewater treatment and water desalination without the need to use energy.