Applications and new developments of biogas technology in Japan

This chapter is to summarize the history and applications of anaerobic technology in Japan for decades to industrial wastewater treatment, sewage sludge digestion and methane fermentation of food/agricultural wastes, based on literature available only in Japanese. Over 300 upflow anaerobic sludge bed (UASB) and expanded granular sludge bed (EGSB) full-scale plants are now in operation for the treatment of beer, soft drink, distillery, food and chemical wastewaters. Anaerobic sludge digestion began in 1932, and is now used in over 300 sewage treatment plants with a total digester volume of 2.1 × 10⁶ m³, producing enough methane to heat the digester or to generate biofuel or electricity. Since the enactment of the Basic Act for the Promotion of the Recycle-Oriented Society, a national program called Biomass Nippon Strategy started in 2002 has attracted much public attention to the concept of converting the annual 89 × 10⁶ tons of livestock wastes to resources. The estimated potentials of methane recovery are 1.6 × 10⁹ m³·y^-1 from the livestock wastes and 1.7 × 10⁹ m³·y^-1 from the municipal solid wastes (MSW). Since 2006, over seventy methane fermentation plants have been in operation treating livestock wastes, and another fifty plants for the treatment of food wastes and the organic fraction of MSW. Recent developments of biogas technology include the application of anaerobic membrane bioreactor and bio-desulfurization of biogas.