Leachates and landfill gas (LFG) are the major problems for closed landfills (CL) and cause significant threats to receiving waterbody and ambient air quality. In this study, a field pilot-scale CL with ex situ nitritation/in situ denitritation process was constructed and operated continuously under wide temperature variations. The effect of low temperature on leachate treatment, and LFG content was studied. Results showed that the combined process can efficiently remove nitrogen and organic matters from leachate, and change LFG content under low-temperature condition. In the ex situ nitritaion, maximum removal efficiencies of ammonia and chemical oxygen demand (COD) were over 99% and 85%, respectively. The loading rate of nitrogen and COD reached 0.5 kg N m⁻³ d⁻¹ and 0.7 kg COD m⁻³ d⁻¹, respectively. The inhibitions of free ammonia (FA) and free nitrous acid (FNA), and low temperature were the key factors affecting nitritation. With recirculating nitrified leachate, total oxidized nitrogen (TON) was completely reduced, and the refuse decomposition was accelerated. Denitritation was the main reaction responsible in the CL. Additionally, methane content was observed lowly at non-inhibitory TON loading rate of 5.8 ± 3.7 g N ton⁻¹ TS d⁻¹. This decrease was not caused by the increased of TON loading, but a carbon source competition by denitrificans. The estimated COD consumption and methane reduction were 55.0 kg d⁻¹ by TON reduction, and 20 m³ d⁻¹, respectively. Hence, this study served a potential strategy for postclosure care of landfills under low temperature variation.

渗滤液和垃圾填埋气 (LFG) 是封闭式垃圾填埋场 (CL) 的主要问题，对接收水体和环境空气质量造成重大威胁。在这项研究中，构建了一个具有异位亚硝化/原位反亚硝化工艺的现场中试规模 CL，并在广泛的温度变化下连续运行。研究了低温对渗滤液处理和LFG含量的影响。结果表明，该组合工艺可以有效去除渗滤液中的氮和有机物，并在低温条件下改变LFG含量。在异位亚硝化中，氨和化学需氧量 (COD) 的最大去除效率分别超过 99% 和 85%。氮和COD的加载率达到0.5 kg N m ^-3 d ^-1和0.7 kg COD m^-3 d ^-1分别。游离氨（FA）和游离亚硝酸（FNA）的抑制以及低温是影响亚硝化的关键因素。通过再循环硝化渗滤液，总氧化氮 (TON) 完全减少，垃圾分解加速。反硝化作用是 CL 中的主要反应。此外，在 5.8 ± 3.7 g N ton ^-1 TS d ^{-1 的}非抑制性 TON 加载率下观察到甲烷含量很低。这种减少不是由 TON 负载的增加引起的，而是由反硝化细菌的碳源竞争引起的。所估计的COD消耗和甲烷减少是55.0公斤d ^-1通过TON减小，且20μm ³ d ^-1， 分别。因此，这项研究为低温变化下垃圾填埋场的关闭后护理提供了一种潜在的策略。