中文摘要：

引言 城市生活垃圾填埋场渗滤液（以下简称为“渗滤液”）中的污染物组成和浓度与填埋场的环境条件、填埋年限等因素密切相关。早期渗滤液含有高浓度较易降解的有机物和氨氮。晚期渗滤液中有机物浓度低而且可生化性差，但氨氮浓度有增无减。理论和实际运行结果表明，完成硝酸盐反硝化需要COD／TKN为4．0，但晚期渗滤液生物脱氮时反硝化的有机碳源不足。因而对于晚期渗滤液处理的重点和难点是：如何经济有效地去除高氨氮，同时在碳源缺乏的情况下，提高总氮去除率。

英文摘要：

Both ＂two-stage upflow anaerobic sludge blanket （UASB） ＋anoxic/oxic （A/O）＂ system and ＂one stage UASB＋A/O＂ system were successively introduced to treat a leachate containing relatively low concentration of organics and high concentration of ammonia from a mature landfill site. The ＂two-stage UASB＋A/O＂ system was used firstly. The denitrification of the return effluent was carried out in the first stage UASB （UASB1） . The nitrification took place in the A/O reactor. The results showed that most biodegradable organic matter was removed in the UASB1, so ＂one stage UASB＋A/O＂ system was used in the second phase experiment. The NH4^＋-N loading rate of A/O reactor and operation temperature were 0.28-0.60 kg NH4^＋-N · m^-3 · d^-1 and 17-29℃, respectively. The COD removal efficiency and the final effluent COD were 50%-70%, 1000-1500 mg ·L^-1, respectively. Short-cut nitrification with 90%- 99% of nitrite accumulation efficiency took place in the system. The NH4^＋-N removal efficiency varied between 90% and 100%. When NH4^＋-N loading rate was less than 0.45 kg NH4^＋-N · m^-3 · d^-1 , the NH4^＋- N removal efficiency was more than 98%, and effluent NH^＋-N was below 15 mg · L^-1. When the ratio of the feed COD to feed NH4^＋-N concentrations was 2-3, the total inorganic nitrogen （TIN） removal efficiency was 70%-80%. The sludge samples from A/O reactor were analyzed by using fluoresence in situ hybridization （FISH） . The FISH analysis showed that ammonia oxidation bacteria （AOB） were 4% of the eubacteria, meanwhile nitrite oxidation bacteria （NOB） were less than 0.2% of the eubacteria.