Study On Sanitary Wastewater Treatment Using Biologic Alaerated Filter With Pre-denitrification

On the basis of studies on BAF (Biological Aerated Filter) actuals home andoverseas, this paper focuses on the experimental study on the Biological Aerated Filterwith pre-denitrification for sanitary wastewater treatment. The paper analyzes theremoval efficiency and regularity of the organic matter and TN, and gets the bestoperating parameters. Also, it will generalize the theory for the advance of theBiological Aerated Filter with pre-denitrification process in wastewater,the dynamicmodel of removing COD is also studied in the paper.The main results are summarizedas follows:1.Taking fly ash ceramic pillar as microbe carrier, microfilm in the system isformed naturally under temperature of18.5～24.5℃in25days.2.The volume ratio of anoxia pillar and aerobic pillar is1:2～1:3and the recyclingratio is200%in the Biological Aerated Filter with pre-denitrification, the effluentconcentration of COD, NH3-N and TN are respectively39.7～57.6mg/L,1.9～3.4mg/L and11.6～15.4mg/L, the removal rate of COD, NH3-N and TN arerespectively80.5%～86.6%,88.4%～92.7%and61.2%～70.4%.3.The filter velocity and HRT have a great influence on the treatment effect of the system. The best filter velocity is2.80m/h,correspondingly,the HRTis20.77min, under this condition, the removal rate of COD, NH3-N and TNare respectively89.3%,97.6%and74.3%,the effluent concentration are respectively26.1mg/L,0.5mg/L and9.8mg/L.4.Under this condition, for a better effluent is gained the discharge standard ofpollutants for municipal wastewater treatment plant (GB18918-2002，the first standard),it is proposed that organic loading and NH3-N loading are respectively less than3.53kgCOD/(m3pillar.d) and0.56kgNH3-N/(m3pillar.d).5.When the height of anoxia pillar and aerobic pillar are respectively0.65m and1.30m, denitrification mainly appeared in the height of0.25～0.5m in anoxia pillar,the degradation of organic materials took place mostly under the height of0.5m inaerobic pillar, the removal of NH3-N appeared above the height of0.5m in aerobicpillar. 6.Back wash has little influence on the removal effect of COD and NH3-N, but ithas great influence on denitrification. The system treating effect can be recovered in3hours after back wash.7.The dynamic model of removing COD is S S exp(KHeo),and the value of...