Research On The Denitrification Performance Of Deep Bed Filter And The Role Of Electrode Strengthening

In this paper,a deep bed biofilter was used in treatment of simulated wastewater and actual wastewater.The effect of depth denitrification was studied.And the parameters of hanging biofilm as well as treating simulated wastewater were studied.Compare the difference between deep bed electrode biofilter and traditional deep bed biofilter in treating simulated wastewater.Research the effect of deep bed electrode biofilter for actual industrial wastewater.During hanging biofilm stage use continuous mode with low load.Control the filtration rate at 0.5m/h,HRT is about 3h,COD of 67-139mg/L,NO₃^--N of 12.75-15.20mg/L.After running 17 days,COD removal efficiency is basically stable,the removal rate is about 60%-70%.Running 19 days,NO₃^--N removal rate reached about 40%-50%.Turbidity removal is good,the removal rate maintained at about 80-90%.Backwash frequency is 10 days,the backwash strength is 5L/（m2·s）.Regular backwashing will cause temporary removal effect reducing.Study on the growth of biofilm in the filter showed that most bacteria existed in the form of zoogloea,while there was bacteria in different shapes of spherical,ellipsoid,filamentous.Select the C/N,filtration rate,carbon source as main parameters in the simulated wastewater treatment stage.Research the impact on the removal of COD and NO₃^--N during the filter operation.The study found when C/N is 5,the treatment effect is better,filter influent NO₃^--N concentration was about 11.9-16.2mg/L,effluent was reduced to about 6mg/L,the removal rate reached 60%.When the filtration rate was 1.5m/h,NO₃^--N removal rate up to about 65%.The carbon source experiment found that sodium acetate is better than industrial glucose.Biomass measurement test found obviously uneven distribution of biomass in the filter.At the top of the filter layer the biomass was up to 14.95 mg VSS/（g·dw）.Biomass decreased along the flow direction.Add electrodes in deep bed filter and constitute the electric biochemical system.Whether in treatment of simulated wastewater or actual wastewater,there was a significant improvement on removal rate of organic matter and nitrogen.In the process of actual industrial wastewater by deep bed electrode biofilter,COD best treatment achieved when current was 10 mA.The removal rate reached 60%.TN best removal achieved when current was 50 mA.The removal rate reached 29%.SS removal was good.Effluent turbidity was substantially below 10 NTU,removal rate reached about 80%.