The Production of Hydrogen and Electricity as New Energy in Anaerobic Wastewater Treatment Processes

The wastewater treatment systems account for 2–3% of the nation's electric load. Novel processes are critical to reduce energy consumption. The study aims at converting the organic substrates in wastewater to new energy sources (hydrogen and electricity) through anaerobic treatment. Hydrogen is produced in anaerobic acidogenic phase, which has a shorter retention time and a higher shock tolerance than traditional methanogenic processes. The results showed the biogas containing more than 60% H2 was achieved in anaerobic hydrogen production reactors. Hydrogen production was closely related with the fermentation types in the reactors. Microbial fuel cell (MFC) is another promising technology to convert the organic compounds to clean energy (electricity). The effects of substrate concentration and bacterial concentration on the voltage generation in MFCs were investigated. Finally, the effluent from anaerobic hydrogen production reactors was connected with MFCs for further contaminant removal and power generation. This study reveals that wastewater treatment plants could possibly be operated as energy production sources through the removal of contaminants, which is significant in progress towards environmental sustainability.