Study On Advanced Treatment And Reuse Process Of Students Apartment Sewage

The Anionic surfactant’s (LAS) content of student apartment wastewater is three or four times as more as municipal sewage, up to7～16mg/L. As a result of poor biodegradation and strong blistering performance of LAS, it is inappropriate to treat the wastewater containing LAS by aeration treatment directly. Due to the pollution characteristics of student apartment sewage, the advanced treatment and reuse process of Hydrolytic Acidification-Biological Contact Oxidation-Biological Aerated Filter for student apartment sewage was proposed. The influences of temperature, pH, initial concentration of LAS and aeration condition on the biodegradation of LAS were investigated. Through the experimental study to discover the technological parameters of Hydrolytic Acidification, Biological Contact Oxidation, Biological Aerated Filter, which conbined with the requirements of recycle water. The results are summarized as follows:(1) LAS is biodegradable in anaerobic environments that proved by shock culturing experiment. Incubation temperature, pH and initial concentration of LAS can affect the biodegradation of LAS, the biodegradation rate increased with the icubation temperature increased and the initial concentration of LAS reduced. The aerobic biodegradation rate of LAS is better than anaerobic biodegradation rate.(2) It lasts only18d for the Hydrolysis-Acidification Reactor being successfully started when applied of aerobic pre-aeration biofilm conbined with rapid sludge discharge. Effect of HRT on hydrolysis acidification experiment showed that when the HRT Hydrolysis Acidification is8h, there is a good removal efficiency of organic pollutant, and the removal rates of LAS and COD is42.12%and46.8%respectively. when the influent concentration of LAS and COD ranging from8～14mg/L and170～250mg/L respectively, the removal ratios maintain43%～45%and42%～47%, ndicating that biofilm Hydrolysis-Acidification reactor has a good resistance to impact load.(3) HRT of Hydrolysis Acidification is set for8h. Biological Contact Oxidation was used in the sewage treatment, and the removal efficiency of Biological Contact Oxidation for pollutants under different HRT was analyzed. The results showed that the optimal HRT for LAS, COD and ammonia-nitrogen to reach the best removal efficiency are different. For LAS and COD, the optimal HRT is3h while4h for ammonia-nitrogen. So the optimal HRT is determined for3h. The research of effect of gas-water ratio on the BAF shows that when the gas-water ratio is12:1, removal efficiency of LAS, ammonia nitrogen and COD are better, which are88%,63%and65.8%respectively, LAS, ammonia nitrogen and COD concentration of effluent is about lmg/L,6mg/L and43mg/L.(4) BAF is used to advanced treatment secondary biochemical effluent. Study on the effect of hydraulic loading, gas-water ratio on removal rate of COD, BOD5, ammonia nitrogen, SS and LAS. The result shows that when the hydraulic loading is3.184m3/(m2.h) and gas-water ratio is2:1, there is a better pollutant removal efficience. Their effluent concentration respectively are15.lmg/L,2.57mg/L,1.34mg/L,5.45mg/L and0.12mg/L, better than recycling requirements. The way of backwash for BAF and operating parameters be determined through tests, fiestly gas flushing for5min, then gas-water flushing for10min, finally, water flushing for5min. Gas flushing and water flushing strength are10L/(m2.s) and5L/(m2.s) respectively. The recoil cycle is5days.(5) Student spartment sewage of an middle school in Guangzhou was treated by Hydrolytic aidification-Biological contact xidation-Biological aerated filter-Ultraciolet sterilizer intergration process, the effluent quality can achieve the requirement of The reuse of urban recycling water-Water quality standard for scenic environment use (GB/T18921-2002), and the cost of one ton of recyle water is only0.49yuan.