两级UASB-A/O-SBR工艺深度处理晚期垃圾渗滤液

摘要

A combined process of a two-stage up-flow anaerobic sludge blanket (UASB), an anoxic/aerobic (A/O) reactor and a sequencing batch reactor (SBR) was used to treat mature landfill leachate, and the influencing factors on short-cut nitrification in A/O reactor were also researched. The operational mode of the process was as follows: Denitrification took place in the first stage UASB (UASB1). The residual nitrite and nitrate of UASB 1 by using the residual chemical oxygen demand (COD) was further removed in the second stage UASB (UASB2). The ammonia nitrogen was removed by short-cut nitrification in the aerobic zone of A/O reactor. The nitrite and nitrate produced from the nitrification were removed in SBR. The experiment results show that the COD and ammonia nitrogen mass concentrations of raw leachate are about 3.0 g/L and 2.0 g/L, respectively. The influent leachate is mixed by raw leachate as well as domestic wastewater in a ratio of 1. The external carbon source (sodium acetate anhydrous) is added in order to enhance the p(C)/p(N) ratio from 1.7 to 3.0. Through the cooperative inhibition of the free ammonia (FA) and free nitrite acid (FNA), the short-cut nitrification is achieved stably in the A/O reactor with more than 70% of the nitrite accumulation ratio. The nitrite and nitrate produced from the nitrification could be removed completely in SBR. The ammonia mass concentration of final effluent is less than 2 mg/L, and its removal efficiency is 99%. The total nitrogen mass concentration of final effluent is about 26 mg/L, and its removal efficiency is about 98%.%应用“两级上流式厌氧污泥床(UASB)-缺氧/好氧(A/O)-序批式反应器(SBR)系统”深度处理实际晚期垃圾渗滤液,研究在A/O反应器中实现并维持稳定短程硝化的影响因素.该系统按如下模式运行:首先在一级UASB(UASB1)中实现反硝化,残余亚硝态氮和硝态氮利用剩余COD(化学需氧量)在二级UASB(UASB2)中通过反硝化被进一步去除,之后在A/O反应器的好氧区进行NH4+ -N的硝化,最后在SBR中去除硝化产生的亚硝态氮及硝态氮深度脱氮.试验结果表明:原渗滤液COD质量浓度仅3.00 g/L左右,氨氮质量浓度在2.00 g/L左右；系统进水采用将原渗滤液与生活污水1∶1混合液,且投加相当于1.56 g/L COD的外碳源无水乙酸钠,将C和N质量浓度比由1.7提高到3.0；通过FA与FNA对NOB的联合抑制,在A/O反应器中实现了稳定的短程硝化,其中亚硝态氮积累率大与70％；产生的亚硝态氮和硝态氮在SBR中被彻底去除;最终出水氨氮质量浓度小于2 mg/L,氨氮的去除率为99％;最终出水总氮质量浓度为26 mg/L,系统总氮去除率接近98％.