Study On The Treatment Of Domestic Sewage And Leachate By PSB

In this study, the unique characteristics of degrading organic matters of PSB and treating domestic sewage and leachate by PSB are investigated.Through experiments we obtain the optimum working condition for treating the two wastewater: â‘ temperature about 25℃, HRT 48h, PSB casting dosage( V_菌/V_污水) 1/4000, pH 7.5, darkness and microaerobic environment, PSB achieve the best performance on domestic sewage treatment, the removal rates of COD_Cr and BOD₅ are 70.88% and 75.10%; â‘¡temperature about 25℃, HRT 96h, pH 8.0, darkness and aerobic environment, PSB achieve the best performance on leachate treatment, the removal rates of COD_Cr and BOD₅ are 69.7% and 75.24%. According to the results of experiments, we discuss the mechanism of degrading organic matters of PSB.For promoting the application of PSB in existing system of wastewater treatment and improving activated sludge method, we combined PSB and activated sludge to treat domestic sewage and leachate. The results show the treatment efficiency is better than those of them resperatively. The common activated sludge need abundant oxygen, but the presence of PSB can make the system of wastewater treatment achieve good performance in microaerobic environment. â‘  In darkness and microaerobic environment, combined PSB-sludge achieves the best performance on domestic sewage treatment, the removal rates of COD_Cr and BOD₅ are 85.65% and81.03%, the water quality index of effluent is up to the first degree of discharge standard of wastewater (GB8978-1996); ?In darkness and aerobic environment, combined PSB-sludge achieves the best performance on leachate treatment, the removal rates of CODcrand BODsare 86.80% and 87.43%, the water quality index of effluent is up to the second degree of leachate emission control standard (GB8978-1997).In order to overcome some shortcomings of mobile PSB and improve technology of PSB, absorption and embedding are chosen to fix PSB in this study, we use acticarbon as absorbent and calcium alginate as embedding material respectively, and introduce immobilized PSB to biological tower filter which is used for treating domestic sewage and leachate. ?The results of domestic sewage treatment indicated that the removal efficiencies of embedding are higher than absorption. When the hydraulic load is 50m3/m2 ? d and the HRT is 19min, the removal rates of CODcrand BOD5 are found to be 91.73 % and 88.85 % respectively, and the water quality index of effluent is up to the first degree of discharge standard of wastewater(GB8978-1996); ?The results of leachate treatment indicate that the removal efficiencies of absorption are higher than embedding. When the hydraulic load is 20m3/m2 ? d and HRT is 81min, the removal rates of CODcr and BOD5 are found to be 96.62% and 97.05% respectively, and the water quality index of effluent is up to the first degree of leachate emission control standard (GB8978-1997). Comparing with mobile PSB, immobilized PSB has many advantages: energy consumption reduces largely, the output of sludge is less, treatment efficiency is obvious better, and HRT is shorter. At the same time, some shortcomings of mobile PSB are overcome, such as the difficult deposition, the low concentration, the weak capability of resisting environmental impact.The costs of construction and operation of the PSB biological tower filter are analyzed in this paper. Comparing with the secondary treatment process, the costs of construction and operation of PSB biological tower filter is much lower. We can draw that the method of PSB can bring more economic benefit.The results of this research has applied to the project design of domestic landfill leachate treatment in Lasha.