Recent Anaerobic Digestion Processes for Energy Recovery from Different Food Wastes

Complete anaerobic organic matter removal process (CARP), in which diluted wastewaters such as sewage and effluent from a methane fermentation digester were treated under anaerobic condition for post-treatment. The chemical oxygen demand (COD) in wastewater was decreased from 4000 ppm to less than 20 ppm. The dry ammonia-methane two-stage fermentation process (Am-Met process) is useful for the anaerobic treatment of nitrogen-rich wastes such as waste excess sludge and food waste produced without the dilution of the ammonia. The plant generating biogas by the decomposition of volatile solid (VS) at a rate of about 820 N m3 per ton of VS. The hydrogen-methane two-stage fermentation (Hy-Met process) is useful for the treatment of sugar-rich wastewaters, in which 2.67 t/d bread wastes were generated 145 m3 of hydrogen/d which corresponds to 214 kwh with 50% efficiency of the fuel cell the conversion system and 514 m3 methane/d which corresponds to 530 l of oil/d.