矿化垃圾床反应器厌氧甲烷氧化协同生物脱氮的研究

Anaerobic methane oxidation coupled to nitrogen removal in mineralized refuse bed bioreactor

垃圾卫生填埋过程中逸散的甲烷与渗滤液处理过程中反硝化段不够彻底产生的硝酸盐对周围环境具有严重的威胁,反硝化厌氧甲烷氧化技术可实现甲烷与硝酸盐的同步去除,极具应用前景.本研究通过模拟垃圾填埋过程,以矿化垃圾作为垃圾填埋的覆土层与反硝化厌氧甲烷氧化微生物的接种源,建立了矿化垃圾床系统.结果表明,反应系统在140 d的运行期间内,硝态氮平均去除速率为34.81 mg·L^(-1)·d^(-1),并且表现出较强的抗冲击能力.反应系统中硝酸盐的去除与甲烷的添加具有直接关系,化学计量学结果表明系统中主要发生的是反硝化厌氧甲烷氧化反应.矿化垃圾上、中、下3层微生物具有明显的空间分异特性,反硝化厌氧甲烷氧化活性呈现上层低、中下层高的趋势,中层与下层的最大反应速率分别是上层的2.33与1.84倍.qPCR结果显示,矿化垃圾床系统中反硝化厌氧甲烷氧化功能基因pmoA和mcrA在中层的拷贝数分别为(7.65×10^(5)±2.62×10^(5))和(9.10×10^(4)±1.72×10^(4))copies·g^(-1),在底层的拷贝数分别为(9.38×10^(5)±1.27×10^(4))和(1.53×10^(5)±7.04×10^(3))copies·g^(-1),均远大于上层的功能基因丰度,同样呈现中下层多、上层少的趋势.本研究可为垃圾填埋场中渗滤液与填埋气的协同处理提供理论技术基础.

The produced methane from landfill gas and nitrate from landfill leachate incompletion denitrification brings severely threaten to the surrounding environment.Denitrifying anaerobic methane oxidation could couple methane oxidation with nitrate reduction which is a promising process for pollution control.In this study mineralized refuse was used as landfill overbarden and DAMO microorganism inoculum and a mineralized refuse bed bioreactor was established.The results showed that the nitrate average removal rate could reach 34.81 mg·L^(-1)·d^(-1) in the whole 140 days operation period and the system exhibited shock resistance ability.The nitrate removal was directly related with methane addition and further experiments demonstrated that denitrifying anaerobic methane oxidation was the main process in the system.The microorganism in mineralized refuse showed significant spatial difference.The DAMO activity was weak in the top but was increased by 233%and 184%in the middle and bottom respectively.The copies of gene pmoA and mcrA were(7.65×10^(5)±2.62×10^(5))copies·g^(-1)and(9.10×10^(4)±1.72×10^(4))copies·g^(-1)(dry refuse)in middle while(9.38×10^(5)±1.27×10^(4))copies·g^(-1) and(1.53×10^(5)±7.04×10^(3))copies·g^(-1)(dry refuse)in bottom.The functional gene in top was much less,which was accordance with microbial activity results.In summary,this study could support theoretical and technical foundation for leachate and landfill gas treatment in landfill process.