Study On Performance Of LSP&PNR Sludge Reduction Process With Phosphorus And Nitrogen Removal

There exist their own disadvantages among all domestic and overseas sludge reduction technologies, which mainly contain worse sludge sedimentation performance, much oxygen demand and worse removal effect of nitrogen and phosphorous. Moreover, along with eutrophication aggravating, nutriment removal, such as nitrogen and phosphorus, has become a most important mission for municipal sewage treatment plant. So far, this issue how to improve the removal effect of nitrogen and phosphorus(especially phosphorus)in sludge reduction systems hasn't been solved perfectly.Therefore, aiming at the problem of worse removal effect of nitrogen and phosphorous in sludge reduction technologies, this paper develops new sludge reduction process——phosphorus and nitrogen removal LSP&PNR process ( i.e., Low Sludge Production Phosphorus and Nitrogen Removal), which can realize phosphorous removal though ejecting rich phosphorous sewage, realize sludge reduction though controlling long SRT and realize nitrogen removal though controlling low DO. And, this study is conducted from the aspects of collectively operating efficiency, influencing factors of sludge reduction and phosphorus and nitrogen removal. The results indicate that:①In LSP&PNR system, under the condition of DO=0.5～1.5mg/L, SRT=50d, while influent COD=362～438mg/L, TN=23.8～51mg/L, TP=5.4～9mg/L, effluent COD<30mg/L, TN=8.5～17.5mg/L, TP≤0.72mg/L. effluent water quality reaches first-degree B standards of《letting standards of town sewage treatment plant》(GB18918-2002). In this system, sludge yield Ys is 0.155gMLSS /gCOD, which shows that comparing with traditional activated sludge process, the effect of sludge reduction in LSP&PNR system reaches 60%. So, the effective connection of sewage treatment, sludge reduction and nitrogen and phosphorus removal can be realized. The results show that the LSP&PNR process with long SRT and phosphorous removal by ejecting rich phosphorous sewage can acquire excellent effect of sludge reduction under the premiss of ensuring effluent water quality to satisfy standards.②It is found through orthogonal test that the optimal operating condition of LSP&PNR process is that HRT of anaerobic tank is 4h, HRT of oxic tank is 4h, ratio of return sludge is 50%. Under optimal operating condition, by researching influencing factors of sludge reduction, containing DO, F/M and SRT, we find that while DO=0.8～1.5mg/L, F/M=0.151gCOD/gMLSS, SRT=50d, Ys of LSP&PNR process is low to 0.14gMLSS/gCOD.