SMALL SEWAGE TREATMENT SYSTEM WITH AN ANAEROBIC, ANOXIC, AEROBIC COMBINED BIOFILTERS

摘要

The present invention is a sewage treatment system that is simple to operate and has a small amount of solids generated, which is suitable for a small sewage treatment plant with a large change in flow rate and water quality. After the sewage flows out of the sediment, the grit is removed, and in the pre-anoxic filter, the supernatant from which SS is removed from the anaerobic reactor and the nitrified treated water by the nitrifying bacteria are used to remove organic matter and denitrification. In the pre-anoxic filter, more than 90% of organic matter in raw water is removed by filtration, adsorption, denitrification, etc., and the aerobic filter is an independent nutrient without competition from heterotrophic bacteria and autotrophic bacteria. Nitrification can stably perform nitrification reaction. Some VS (Volatile Solid) components of the sludge accumulated in the lower portion of the anaerobic reactor are oxidized and methanated by digestion to be used as a carbon source for denitrification. Sludge is reduced by VS in the sludge removed due to digestion, which can reduce the amount of solids produced during sewage treatment. In the post-anoxic filter, denitrification is carried out using external and internal carbon sources, and SS and turbidity can be removed by biofilm formation in the filter.