The Application Research On Biological Aerated Filter System In Contaminated River Water Treatment

Dianchi lake watershed is located in the eastern of yunnan-guizhou plateau. Because it is the lowest point of Dianchi lake watershed, there are twenty multiple rivers injected into it appeared of centripetal shapes. These rivers most flow through the farmland, towns, phosphate rock area etc, accepted many urban sewage,and pollution which is scoured by rain such as sewage, rural junk, human feces, sediment etc. At the same time, because of its less natural supplies water, Dianchi lake is polluted very severely. In China, it is a typical heavy polluting lake.Xinyunliang River, which is located in the west of Kunming PanLongJiang, is the mainly water release and pollution discharge river. In the dianchi lake pollutant carrying river system, xinhe-yunliang river system accepts 41.28% of the whole basin industrial wastewater quantity. This task selects the topic organic pollution river—xinyunliang river as the research object, relying on the comprehensive unfolded engineering which are synthesized renovating and dirt cutting in dianchi lake watershed of the north shore, based on strict dirt cutting, carry out the engineering which is based on biological landscape strengthened denitrification and dephosphorization.This task includes six topics, biological aerated filter is an important project. Biological aerated filters is developed in recent years which is a wastewater aerobic biological treatment process. Compared with other ordinary activated sludge method, BAF covers a small area (about ordinary active sludge's one third);has a high organic load; needs less investment (save 30%); won't produce sludge bulking and outlet water quality is good etc.Biological aerated filter removes organic pollutants is mainly due to the efficient biofilm which grows in the packing surface of the stuffing based on the effects of oxidation,filtration,flocculation, so BAF has a strong removal ability of suspended substance and organism. Meanwhile, through controlling dissolved oxygen content, BAF also can produce good nitrification and denitrification. Because BAF covers a small area; needs less investment; be operated easy; can not set up the second pond, it is a kind of new water treatment technologies which has a certain economic benefits and environmental benefits.The experiment uses polluted river water as the research object, through pilot test to research the BAF system, the research result indicates that:(1)Under the condition of reflux 125%,when the load are 2.4m3/d and 3m3/d,the removal rates of the COD, ammonia nitrogen, total nitrogen removal are respectively 36.4%-77.4%,63.4%-93.5%,26%-50% and 36%-53.6%,76%-93.2%,20.8%-44.7%. (2)Under the condition of 2.4m3/d, removal rates for the COD, ammonia nitrogen, total nitrogen removal are respectively 25%-60.8%,75.3%-94.3%,8.5%-29%; under the condition of reflux 125%, BAF system has a higher effect.(3)Substrate concentration and organic matter degradation rate satisfy level 1 dynamics equations: effluent water of organic content can be estimated by:...