| 摘要 |
PURPOSE:To reduce operation costs and increase the reaction rate of an anaerobic digestion by a method wherein raw sewage is subjected to solid-liquid separation to remove solids in suspension therefrom, ammonia is set free by heat application and gas-to-liquid contact, BOD is removed by methane fermentation with fixed methane-forming bacteria and the liquor thus treated is subjected to another biological nitrification-denitrification treatment. CONSTITUTION:SS and colloid in raw sewage 1 are flocculated and the flocculated mass undergoes a solid-liquid separation process 3 to obtain a SS-free sewage 4 and the sludge 5 separated therefrom. The sludge 5 is separated into a dehydrated cake 7 and the liquor 8 removed therefrom by a sludge dehydrator 6. The sewage 4 and the liquor 8 are heated to be decomposed into NH3 and CO2 which are then set free. The liquor 14 flowing out from a NH3 strip process 11 is supplied into a methane fermentation process 8 to convert a soluble BOD into CH4 and CO2 for removal. An outflow liquor 24 resulting from methane fermentation undergoes a biological nitrification-denitrification process 25 for further treatment, since a small amt. of BOD and NH3, a large amt. of COD and PO4<3-> and chromaticity remain in the liquor 24. |
