晚期垃圾渗滤液两级UASB-A/O-SBR工艺短程深度脱氮

采用"两级上流式厌氧污泥床(UASB)-缺氧/好氧(A/O)-序批式反应器(SBR)工艺"对城市生活晚期垃圾渗滤液进行了深度处理.运行模式如下:首先在一级UASB(UASB1)中反硝化,UASBI出水中的亚硝态氮和硝态氮利用残余COD在二级UASB(UASB2)中被进一步去除,在A/O反应器中利用残余COD进行反硝化以及将NH4+-N硝化,在SBR中去除硝化产生的亚硝态氮、硝态氮.试验中首先采用原渗滤液进入处理系统(20d),然后采用原渗滤液与生活污水1∶1混合进入系统实现和维持稳定的短程硝化(60d),最后采用原渗滤液与A/O反应器出水1:1混合进入系统实现和维持稳定的短程硝化(60d).140d的试验结果表明:原渗滤液的总氮浓度为2 300 mg·L-1,氨氮浓度在2 000mg·L-1左右时,通过将原渗滤液与生活污水或A/O反应器出水1:1混合,可以在A/O反应器中实现稳定的短程硝化,其中亚硝态氮积累率为70%～88%.后续的SBR工艺,可彻底去除产生的亚硝态氮和硝态氮.最终出水的氨氮浓度不到2 mg·L-1,总氮浓度为18～20mg·L-1,系统氨氮和总氮去除率分别为99.7%和98%.

Advanced Nitrogen Removal via Nitrite from Mature Landfill Leachate by the Two-stage UASB-A/O-SBR Process

The treatment of mature leachate from municipal landfill was investigated by using a system of a two-stage up-flow anaerobic sludge blanket(UASB),anoxic-oxic(A/O) reactor and a sequencing batch reactor(SBR).During operation,denitrification took place in the first stage UASB(UASB1).The effluent nitrite and nitrate of UASB1 was further removed in the second stage UASB(UASB2) by using the residual chemical oxygen demand(COD).And then the denitrification was accomplished by using the residual COD in the anoxic zone of A/O reactor.And the ammonium nitrogen was removed via nitrite in the oxic zone of A/O reactor.At last,the nitrite and nitrate which was produced by the nitrification was removed in SBR.The experiment experienced three stages during 140 d.Raw leachate was pumped in the system at the first stage(20 d).The raw leachate mixed with domestic wastewater in the ratio of 1 was pumped in the system at the second stage(60 d) to achieve the partial nitrification and denitrification stably.The raw leachate mixed with the effluent of A/O reactor in the ratio of 1 was pumped in the system at the last stage(60 d),and partial nitrification and denitrification was achieved stably.The operational results of 140 d were that the total nitrogen(TN)and ammonium nitrogen concentrations of influent were about 2 300 mg·L-1 and 2 000 mg·L-1,respectively.The partial nitrification was achieved stably in the A/O reactor at the second stage and the third stage.The nitrite accumulation ratio was 70%～88%.The nitrite and nitrate which were produced by the nitrification in the A/O reactor could be taken out relative completely in SBR.The ammonium nitrogen concentration of final effluent was less than 2 mg·L-1.The TN concentration of final effluent was 18～20 mg·L-1.The ammonium nitrogen and TN removal efficiency were 99.7% and 98%,respectively.