游离氨抑制协同过程控制实现渗滤液短程硝化

Achieving the nitrite pathway using FA inhibition and process control in UASB-SBR removing nitrogen from landfill leachate

采用UASB-SBR生化系统处理高氮晚期渗滤液为研究对象,在获得稳定有机物和氮去除的前提下,考察了采用游离氨(FA)协同过程控制对实现渗滤液长期稳定短程硝化的可行性,建立实现与维持SBR系统内稳定短程硝化的途径及方法.试验结果表明:经过36d的运行,SBR系统的亚硝积累率始终稳定在90%以上,获得了稳定的短程硝化.游离氨和过程控制的协同作用是实现与维持SBR反应器稳定短程硝化的决定因素,以DO,ORP和pH作为渗滤液短程硝化反硝化的过程控制参数是可行的,在充分利用较高FA抑制亚硝酸盐氧化菌活性的前提下,过程控制能够准确判断硝化终点,避免过度曝气破坏短程硝化,从而为氨氧化菌(AOB)的生长创造有利条件,有效抑制亚硝酸盐氧化菌(NOB)的生长并逐渐从系统中淘洗出去,实现了硝化菌种群的优化,荧光原位杂交技术(FISH)检测也证明这一点.在此基础上,通过批次实验考察了微生物种群的反硝化动力学特性,符合Monod动力学方程,NO2--N基质最大比利用速率和半饱和常数分别为0.44gNO2--NgVSS-1d-1和15.8mgL-1.

An up-flow sludge blanket （UASB） and sequencing batch reactor （SBR） system was introduced to remove organic and nitrogen from landfill leachate. The syngertic effect of free ammonia （FA） inhibition and process control were used to achieve nitrite pathway in the SBR. In previous reseach,inhibition of FA on nitrite oxidizing bacteria （NOB） activity has been revealed and process control parameters （DO,ORP and pH） exactly indicate the end-piont of nitritation. The method was implemented in the SBR achieving stable nitrogen removal via nitrite pathway from landfill leachate. The degree of nitrite accumulation during the nitritation was monitored along with the simultaneous and advanced removal of organic and nitrogen in the UASB-SBR system. The nitrifying bacteria community was quantativly analyzed by fluorescence in situ hybridization （FISH） techniques. Batch tests were carried out to investigate the denitritation kinetics of microbial bacteria in the SBR. Experimental results showed that the nitrite pathway could be repeatedly and reliably achieved by syngertic effect of FA inhibition and process control. FISH analysis showed the dominant nitrifying bacteria was Ammonia-oxidizing β-Proteobacteria. Relationship between nitrite concentration and nitrite reduction rate followed the Monod-type equation and the maximum specific nitrite utilization rate （k） and half-velocity constant （Ks） were calculated as 0.44 gN gVSS^-1 d^-1 and 15.8 mg L^-1,respectively.