Nitrogen And Phosphorus Removal With Enhanced Sbr Process For The Low Concertaion Urban Sewage

As conventional biological nitrogen and phosphorus removal processes with carbon,sludge age,nitrate and other issues which makes the N, P highly efficient and stable remove poorly at the same time,due to the same mixed-culture microorganism in the system;In particular, when using conventional process to treat the low concertaion urban sewage, the system will be in the low load state, which can not provide sufficient nutrients for micro-organisms, so that more of these conflicts intensified. In the works conditions, This experiment will use new biological process for the low-concentration wastewater treatment, in order to improve the efficiency,simplify the operation and to ensure that pollutants can be discharged standard.Utilize the BICT device, the total volume is 165 m3 , which carried out the preliminary study about dealing with the low concentrations sewage. At the same time, we found that sludge mixed culture may not be the main constraints factors to deal with low concentration sewage,so use of BICT equipment to treat low concentration wastewater with enhanced SBR process. The experimental results as follows:(1) The BICT process has good effect at handling capacity from 190 m3/d to 260 m3/d,HRT 13.67h and influent organic load 0.35kgCOD/m3.d. Under the controlled conditions: SRT is 15d, cycle is 4.5h,filling rate is 1/2,recycling rate of sludge is 30%;The average removal rate of COD,NH3,TN,TP are 65%,60%,18%,88%, and the Effluent concentration up to GB18918-2002 grade A standards.(2) the SBR process with sludge transfer (enhance SBR process) can effectively increase its handling capacity without affecting the processing. Using 30% of the sludge reflux ratio can raise handling capacity from 240 T/d to 310 T/d, when the HRT is 8.52h, the organic load is 0.5kgCOD/m3.d,and Under the controlled conditions: filling(30min), filling/aeration(30min), aeration(30min), sedimentation(30min), decanting(60min); The effluent COD,ammonia nitrogen,TN,TP concentrations are 45mg/l,0.3mg/l,7.9mg/l,0.17mg/l,The average removal rate of COD,NH3,TN,TP are 70%,98%,48%,87%, and the Effluent concentration up to GB18918-2002 grade A standards.(3) Sludge transfer in the system can improve the response phase of the sludge concentration, and can reduce the decanting phase of the sludge concentration, which is one of the main reasons to improve the handling capacity.(4) Sludge transfer could improve the performance of sludge settlement;Using 30% of the sludge reflux ratio, Sludge settlement index can reduce from 140 to 93. Sludge transfer can also improve Phosphorus Removal Performance,to achieve PAOs'enhanced phosphorus removal. The above two points just show that the enhanced SBR's anaerobic biological selector not only provide places for PAOs to achieve enhanced phosphorus release, but also filter out the strong flocculation microbial.