The Application Of SBR Process In Treating The Sewage In Sealed Toilet Of Passenger Train

COD concentration of the sewage in sealed toilet of passenger train is high which can reach to an average value of 6000mg/L or so after the water quality research. TN component has the same problem of high concentration with an average value of 2000mg/L or so, which is similar with TN. Suspended solids(SS)also has a high content and the datas for SS and volatile suspended solids(VSS)are 5000mg/L and 3000mg/L or so, respectively. In this paper, use SBR(Sequencing Batch Reactor)to deal with the sewage in sealed toilet of passenger train directly and the one which has a pretreatment of nitrogen removal, then do some researches between the treatment effect of the two processes.SBR process which directly deals with the sewage in sealed toilet of passenger train illustrates that: i)Removal rate of COD can reach to 50% with the treatment of SBR process, however, aeration time that exceeds 12h has a limit effect on the COD removal rate. ii)When the NH3 N concentration is 1500mg/L with the operating period of 24h, which including 12h for aeration, 10h for stirring run and 2h for settlement alternately, the removal rate of NH3 N is 70%. And when the NH3 N concentration is 500mg/L, accompanied by the operating period of 24h, which including 2h for stirring run, 8h for aeration, 12h for stirring run and 2h for settlement alternately, the removal rate of ammonia is 80%, on the same condition, while the NH3 N concentration is 1000mg/L, the removal rate is 50%. iii)Denitrification rate of SBR with the stable operation ranges from 10% to 40%, meanwhile extending the hypoxia time and reducing the influent of TN will do good to the denitrification efficiency. iv)In case of no mud discharging, SBR for phosphorus removal rate ranges from 10% to 60%.SBR process dealing with the sewage in sealed toilet of passenger train with nitrogen removal illustrates that: i)With the conditions of 20~25℃, pH7.5, 2 to 3mg/L for DO concentration, 8h for reaction run(3 period a day), including 6h for aeration, 1.5h for settlement and 0.5h for drainage and idle, the SBR system can achieve the best operating condition and the removal efficiency is optimal. With a COD removal rate is between 76.3% and 84.8%, and that of NH3 N is 61.0% to 65.4%. ii)A combination of optimal working time of anaerobic(anoxic)/aerobic, shows that the treatment effect of two class A/O is optimal, whose specific operating mode is watering immediately+ anaerobic 1h+ aerobic 3h+ anaerobic 1h+ aerobic 3h+settling 2h+drainage. The average removal rate for COD and NH3 N are 72.0% and 70.2% respectively. iii)Comparing the optimal running reaction parameters between traditional SBR process and two class A/O SBR process, We can see that removal rate of the latter one is higher than that of the former one. The former COD removal efficiency is 64.3% to 72.3% and the one of NH3 N is 61.0% to 65.4%. The latter COD removal efficiency is 71.0% to 76.8% and the one of NH3 N is 67.1% to 72.9%. Therefore, choose the latter one to treat the sewage of sealed toilet of passenger train with nitrogen removal.