“…Water pollution is now a global issue accompanied by rapid development of the human society. − To solve this problem, various technologies for wastewater treatment have been proposed, for example, physical adsorption, membrane distillation, chemical oxidation, and biodegradation . Actually, there exists a huge amount of energy stored in wastewater in the form of chemical energy. ,, Although the above technologies can effectively remove the hazardous substances (metal ions, pathogen, organics, etc. ), the nonuse of chemical energy in the wastewater results in the abundant waste of energy. ,, Moreover, a great deal of energy is consumed during these processes.…”