高氮城市生活垃圾渗滤液短程生物脱氮

Nitrogen removal from high nitrogen municipal landfill leachate via nitritation and denitritation

采用“两级UASB-缺氧-好氧系统”处理高COD与高NH4^＋-N的城市生活垃圾渗滤液.180天的试验结果表明：UASB1（一级UASB）与UASB2（二级UASB）最大COD去除速率分别为12.5、8.5 kg·m^-3·d-1,UASB1的NOx--N的最大去除速率为3.0 kg·m^-3·d^-1.系统COD去除率为80%～92%,出水COD为800～1500 mg·L^-1.原渗滤液的NH＋4-N为1100～2000 mg·L^-1,A/O工艺的最大NH4^＋-N去除速率为0.68kg·m^-3·d^-1;在17～30℃,通过NO-2-N累积率为90%～99%的短程硝化,NH4^＋-N的去除率在99%左右,出水NH4＋-N小于15 mg·L^-1.回流处理水和二沉池回流污泥中的NOx^--N分别在UASB1和A/O工艺的缺氧段实现完全反硝化,使系统无机氮TIN去除率达80%～92%.同时高效的反硝化为硝化提供了充足的碱度,使A/O工艺pH大于8.5,维持较高的游离氨浓度,结果表明,高游离氨（FA）是导致短程硝化的主要因素.以pH作为控制参数调控A/O工艺的曝气时间,可以有效的抑制亚硝酸盐氧化菌（NOB）的增长,实现种群优化和稳定的短程硝化.

A system consisted of two -stage UASB-Anoxic/Oxic reactor （A/O） was used to treat municipal landfill leachate with high COD and ammonia concentration. The 180 days operational results showed that the maximum organic removal rate in UASB1 and UASB2 was 12.5 and 8.5 kg·m^3·d^-1, respectively. The maximum NO,-N removal rate in UASB1 was 3.0 kg·m^3·d^-1. COD removal efficiency of the system was 80% -92% with effluent COD of 800～1500 mg·L^-1. At the rawNH4^＋-N of 1100-2000mg·L^-1, the maximum NH4＋-N removal rate was0.68 kg·m^-3·d^-1. At 17-30℃, the NH4^＋-N removal efficiency was about 99% by nitritation with effluent NH4^＋-N less than 15 mg·L^-1. The NOx-N in recirculated effluent and return sludge was completely denitrified in the UASB1 and anoxic zone of A/O reactor, respectively. The total inorganic nitrogen （TIN） removal efficiency was 80% -92%. Due to the alkalinity supplement from complete denitrification, pH was more than 8.5 causing the maintenance of high-strength free ammonia （FA） in the A/O reactor. High-strength FA was a main reason resulting in nitritation. The aeration time in the A/O was adjusted by using pH as controlling parameter to achieve microbiological community optimization; meanwhile the stable nitritation was attained.