Hydrogen is commonly accepted as one of the core renewable energy fuels we need. Modern wastewater treatment technology is a potential source of this fuel for the future. It is well established that methane or natural gas is produced by anaerobic digestion of the kind commonly found in water treatment operations. Biogas plants rely on anaerobic digestion, a fermentation process in which waste is digested by microbes to produce methane gas (biogas). The waste can be converted into biofertilizer and spread directly onto fields, or the biogas itself can be used interchangeably with natural gas as fuel. Like fossil-derived natural gas, this can be reformed to extract the hydrogen. Anaerobic treatment is seen as a proven key technology for recycling energy and wastewater nutrients since it transforms organic material into hydrogen and methane that provide electricity and heat and at the same time provides low levels of excess sludge. Biohydrogen has been developed and suggested as the ultimate transport fuel for vehicles and vessels due to its non-polluting nature and also allows the use of highly efficient fuel cells to turn chemical energy into electricity. In the last decade many innovations for processing biohydrogen have been proposed including bio-photolysis, photo fermentation, microbial fuel cells/electrolysis (MECs and MFCs), and dark fermentation, last seems to be the most pragmatic and feasible.

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