(JP2000015231-A)   NOVELTY - Methane fermentation of organic waste uses circulatory system of interconnected fermentation and membrane separation tanks.    USE - For methane fermentation of organic waste including night soil, septic tank sludge, agricultural sludge, sewage sludge, farm animal manure, kitchen refuse and food waste.    ADVANTAGE - The concentration of methane bacteria in the fermentation tank is held at a high value to increase fermentation efficiency. Fermentation inhibition due to volatile fatty acids or ammonia nitrogen is reduced.    (JP2000024661-A)   NOVELTY - Methane fermentation of organic waste uses circulatory system of interconnected fermentation and membrane separation tanks.    USE - For methane fermentation of organic waste including night soil, septic tank sludge, agricultural sludge, sewage sludge, farm animal manure, kitchen refuse and food waste.    ADVANTAGE - The concentration of methane bacteria in the fermentation tank is held at a high value to increase fermentation efficiency. Fermentation inhibition due to volatile fatty acids or ammonia nitrogen is reduced.    (JP2000061274-A)   NOVELTY - Methane fermentation of organic waste uses circulatory system of interconnected fermentation and membrane separation tanks.    USE - For methane fermentation of organic waste including night soil, septic tank sludge, agricultural sludge, sewage sludge, farm animal manure, kitchen refuse and food waste.    ADVANTAGE - The concentration of methane bacteria in the fermentation tank is held at a high value to increase fermentation efficiency. Fermentation inhibition due to volatile fatty acids or ammonia nitrogen is reduced.    (JP2000061433-A)   NOVELTY - Methane fermentation of organic waste uses circulatory system of interconnected fermentation and membrane separation tanks.    USE - For methane fermentation of organic waste including night soil, septic tank sludge, agricultural sludge, sewage sludge, farm animal manure, kitchen refuse and food waste.    ADVANTAGE - The concentration of methane bacteria in the fermentation tank is held at a high value to increase fermentation efficiency. Fermentation inhibition due to volatile fatty acids or ammonia nitrogen is reduced.