The Study Of Landfill Leachate Treatment By MBR+NF+RO Processes

This paper focuses on a study about the landfill leachate of a town in Heilongjiang Province, uses the MBR+NF+RO joint technology for experimental research, with the research of the A/O-MBR process, the nanofiltration and reverse osmosis technology, and the treatment effects of the COD, ammonia nitrogen and total nitrogen in the landfill seepage filtrate; at the same time, through the study of the factors such as dissolved oxygen, p H, hydraulic retention time, sludge concentration and the ratio of nitrification liquid reflux on the biological system, this paper also deals with the effects of external influence MBR, analyzes of the membrane fouling case, gets some specific findings are as follows:First, the county landfill leachate has the feature with high concentrations of organic matter and strong toxicity. After using the way of inoculation sludge acclimation, through the observation about the reactor of MLSS, SV30, COD and NH3-N, finds out that a large amounts of biological phase with sludge sedimentation and good performance, the effect of the contaminant removal gets better, the types of microorganisms advances, which shows that after 37 days of training and acclimatization, the MBR biochemical systems starts successfully.Secondly, because of the high ammonia concentration in leachate, this article focuses on the A/O-MBR biological denitrification process. The results show that A/O-MBR process for the removal of organic matter has a better effect; COD removal rate is 91.5%; which is the main effects of the microorganisms downgrade organics removal; furthermore, ultrafiltration strengthen the MBR process on the removal rate. A/O-MBR process makes the process of denitrification better, ammonia nitrogen and total nitrogen removal rate can be reach to 86.7% and 88% respectively. Although UF removal efficiency is small, it can strengthen the nitration reaction system, thereby improved ammonia removal. Through the analysis of the effects of various operating parameters, the optimum operating parameters of the system is the nitrification tank DO = 1.5~2.5mg/L, the denitrification tank DO = 0~0.5mg/L, p H = 7~8, MLSS = 3000~4000mg/L, IR = 300%.Finally, the treatment effects of the nanofiltration and reverse osmosis systems and the joint technology for landfill leachate are discussed. For the nanofiltration systems, the removal rates of the COD, NH3-N and TN in the ultrafiltration water leachate are 86.17%, 60% and 60.91%. While for the ultrafiltration water reverse osmosis system leachate, the removal rates are 87%, 73.50% and 72.29%. According to the effects of removing the pollutants, reverse osmosis systerms is better than nanofiltration technology, which means reverse osmosis process is particularly applicable to the effluent with high content of nitrogen. Using joint processes with MBR+NF+RO treatment to the landfill leachate, the removal rates of the COD, NH3-N and TN reach to 99%, 98.41% and 97% respectively, the process of the experiment running smoothly, so the quality of the effluent can match the discharge standards.