Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
Environ Pollut. 2019 Jul;250:863-872. doi: 10.1016/j.envpol.2019.04.111. Epub 2019 Apr 27.
Microaerobic and hypoxic methane oxidation coupled to denitrification (MAME-D and HYME-D) occur in stabilized landfills with leachate recirculation when biological denitrification is limited by lack of organics. To evaluate nitrate denitrification efficiency and culture MAME-D/HYME-D involved bacteria, a leach bed bioreactor semi-continuous experiment was conducted for 60 days in 5 runs, under nitrate concentrations ranging of 20 mg/L-55 mg/L, wherein 5% sterile leachate was added during runs 4 and 5. Although the HYME-D system demonstrated high denitrification efficiency (74.93%) and nitrate removal rate reached 2.62 mmol N/(L⋅d), the MAME-D system exhibited a denitrification efficiency of almost 100% and nitrate removal rate of 4.37 mmol N/(L⋅d). The addition of sterile leachate increased the nitrate removal rate in both systems, but caused the decrease of methane consumption in HYME-D. A stable isotope batch experiment was carried out to investigate the metabolic products by monitoring the CO and NO production. The production of organic intermediates such as citrate, lactic acid, acetate, and propionic acid were also observed, which exhibited a higher yield in HYME-D. Variations in the microbial communities were analyzed during the semi-continuous experiment. MAME-D was mainly conducted by the association of type Ⅰ methanotroph Methylomonas and the methylotrophic denitrifier Methylotenera. Methane fermentation processed by Methylomonas under hypoxic conditions produced more complex organic intermediates and increased the diversity of related heterotrophic denitrifiers. The addition of sterile real leachate, resulting in increase of COD/N, influenced the microbial community of HYME-D system significantly.
在采用渗滤液回灌的稳定化垃圾填埋场中，如果生物反硝化受到有机物缺乏的限制，则会发生微需氧和缺氧甲烷氧化耦合反硝化（MAME-D 和 HYME-D）。为了评估硝酸盐反硝化效率并培养参与 MAME-D/HYME-D 的细菌，在 5 个运行周期中进行了为期 60 天的渗滤床生物反应器半连续实验，硝酸盐浓度范围为 20 mg/L-55 mg/L，其中在运行 4 和 5 期间添加了 5%的无菌渗滤液。尽管 HYME-D 系统表现出高的反硝化效率（74.93%）和硝酸盐去除率达到 2.62 mmol N/（L⋅d），但 MAME-D 系统表现出几乎 100%的反硝化效率和 4.37 mmol N/（L⋅d）的硝酸盐去除率。无菌渗滤液的添加增加了两个系统的硝酸盐去除率，但导致 HYME-D 中甲烷消耗减少。通过监测 CO 和 NO 的产生进行了稳定同位素批量实验，以研究代谢产物。还观察到柠檬酸、乳酸、乙酸和丙酸等有机中间产物的产生，在 HYME-D 中表现出更高的产率。在半连续实验中分析了微生物群落的变化。MAME-D 主要由 I 型甲烷氧化菌 Methylomonas 和甲基营养型反硝化菌 Methylotenera 共同作用完成。在缺氧条件下由 Methylomonas 进行的甲烷发酵会产生更复杂的有机中间产物，并增加相关异养反硝化菌的多样性。无菌实际渗滤液的添加，导致 COD/N 增加，对 HYME-D 系统的微生物群落产生了显著影响。
