Integration of hydrogen production and waste heat recovery in electrochemical wastewater treatment

Electrochemical wastewater treatment using thin-film diamond electrode has been applied in industrial wastewater treatment where highly toxic organic compounds are present. In these applications, reduction of electric energy consumption and recovery of waste heat energy are key factors that impact the competitiveness of electrochemical wastewater treatment. This paper presents design, fabrication and testing of the electrochemical reactor for wastewater treatment along with hydrogen production and waste heat recovery. Experiments were carried out to measure the decrease of COD concentration on anode, the simultaneous formation of hydrogen on cathode and the increase of electrolyte temperature. The impact of electric current density on electrolyte temperature was studied. Experimental study and energy efficiency analysis on hydrogen production and waste heat recovery have shown that the technology presented in this study is feasible, allowing us to achieve both economic and environmental benefits. ► Organics decomposition, H2 production and heat recovery are performed simultaneously. ► Thin-film diamond electrode decomposes organics and increase H2 production rate. ► Electrochemical processing improves economics of wastewater treatment.