The Investigation Of The Quality Of The Train's Wastewater And The Treatment Effect Of SBR-MBR Technology

This thesis mainly studies the quality characteristics of wastewater from the train toilet, depot septic tank inlet and outlet of North China train station and septic tank effluent treated by anaerobic process. According to the characteristics of anaerobic effluent quality, chemical precipitation method is used to remove nitrogen and phosphorus from anaerobic effluent, and aerobic SBR technology and integrated aerobic MBR process are used to treat the effluent followed by pretrement.The investigation research data indicates that wastewater of the train toilet and depot septic tank inlet and outlet from railway station has the features of "high ammonia", "high organic" and "high SS". In addition, the phosphorus content ranges from 50mg/L to 100mg/L, it also has a "high phosphorus" characteristics. Comparing the water quality index of the depot septic tank inlet and outlet, the septic tank can fight against the influent water quality changes in load and balance the septic tank effluent quality.The septic tank effluent has distinctive features of high ammonia nitrogen and high phosphorus by the treatment process of anaerobic ABR-AF series. The pre-experiment is focus on removing ammonia and phosphate by chemical precipition method, which is conducted before the aerobic biochemical treatment process. Pre-experimental data shows that it can be achieved good treatment effect under a relatively low cost, in the condition of n(Mg²⁺): n(NH⁴⁺): n(PO₄^3-) materials ratio 1:1:0.9, reaction time of 20min and pH 8.0. Ammonia nitrogen removal rate can reach 95%, the rate of phosphate removal is in place between 30-70%.Aerobic SBR-MBR process is used to treat the pre-treatment septic tank effluent. The SBR process parameters are selected cycle time12h, sedimentation time 3.5h, water inlet and outlet time 0.5h, import content 2L ( equivalent to the hydraulic retention time of 48h ), ammonia concentration control in 350⁴00mg/L range. The following are the effluent water quality in the stable operation period: COD concentration of 250mg/L or so, ammonia concentration in the 150mg/L or so, total nitrogen concentration in the 270mg /L or so, the treatment effect is not satisfactory. Finally, the SBR effluent is treated by the MBR reactor, and continuous monitoring can be found in MBR reactor, the COD removal rate is around 60%, and the effluent concentrations up to 100mg/L, which can achieve the primary standard of"integrated wastewater discharge standard". MBR reactor for ammonia nitrogen removal effect is very ideal, removal rate is above 95%, and ammonia concentration in effluent is steady in 15mg/L. But MBR reactor is not good at removing TN, and removal rate of TN does not reach 20%.