Research On Treating Effluent Form Munici-pal Sewage Treatment Plant By BAF

This paper,takes the depth treatment plant which swage treatment capacity is10000m³/d for research object,held on the experimental reseach on the biologicalaerated filter process advanced treated effluent which was come from two class citysewage plant.By monitoring the water quality index that COD_Cr, BOD₅, SS, watertemperatureamm, onia nitrogen, total nitrogen, total phosphorus, nitrate nitrogen,nitrite nitrogen of in and out of the water conclude the treatment effect of actualoperation of BAF process for advanced treatment of two class city sewage plant,andtook a researche on hanging membrane. and discusses the main factors such astemperature, water quality, load and other factors that influence on removal efficiency.Finally, some questions and solution about BAF technology in the actual operationwere presented.The research results show that:（1） The plant biological aerated filter process selected the hanging membranemethod, hanging membrane finished about in16days, and the result showed COD_Crand ammonia nitrogen removal rate could not stand for hanging membrane finishing.（2） COD_Crremoval rate based on BAF process was16.6%in average which is failto reach the effluent standard. This is mainly due to hydraulic load, water temperature,water quality, the volume load and other factors.（3） Removal rate of BOD₅is continuously increase to86.9%following the addingof organic load,this is means that BAF process has a good load-bearing capacity. Onthe biodegradability of water, the concentration of BOD₅keep the pace in the samegrowth with the removal rate of BOD₅.This is indicates that biological membrane hasprefect removal rate of BOD₅.（4） Removal rate of ammonia nitrogen was50.5%in average when watertemperature is20degrees above. Its removal effect is comparatively good. at a good removal effect Low concentration of dissolved oxygen and ammonia onthe biological membrane surface plays an inhibitory action to oxidation of nitrite thatlead to nitrogen of nitrite accumulation. The study on BAF technology shows that itsremoval rate to total nitrogen, total phosphorus is very low,5.5%,1.8%respectively.（5） The inflow water quality plays a key role on SS removal rate, while watertemperature and hydraulic load does not have a big impact on SS removal rate.