外源菌剂加速好氧填埋初期稳定化速率及菌群演替分析

Microbial Inoculation for Accelerating Early Stabilization and Microbial Succession in Aerobic Landfill Reactors

好氧稳定化技术是填埋存量垃圾处理及污染控制的重要工艺,也是开展填埋场地生态修复的重要基础。为进一步提高填埋稳定化速率,该研究提出了以好氧曝气和微生物接种为基础的生物强化好氧填埋技术。在厌氧、曝气接种以及不同垃圾含水率(37.5%、43.9%、46.7%和52.0%)条件下开展了5组模拟填埋试验,探究了填埋降解52 d过程中反应器堆温、堆体质量、垃圾含水率及有机质含量的变化规律,并解析了堆体内微生物的菌群结构,预测了微生物的功能特征。结果表明:①生物强化好氧填埋组的有机质降解率比厌氧填埋组高6.38%~25.28%,好氧降解过程分为高温期、次高温期和温度稳定期3个阶段。②对比不同垃圾含水率条件下的好氧填埋效果,发现含水率为37.5%的低含水率组微生物产热和垃圾降解效果较佳。③微生物多样性分析发现,外源投加的微生物物种可在好氧填埋堆体内存活,生物强化好氧填埋高温阶段的优势微生物为厚壁菌门(Firmicutes)的八叠球菌属(Sporosarcina),其可在偏碱性条件下生长。④降解菌群主要具有锰氧化、化能异养、发酵、氮和硫氧化等功能,垃圾含水率与锰氧化功能基因丰度呈正线性关系,与化能异养功能基因丰度呈负线性关系。研究显示,外源菌剂接种和好氧曝气组合技术在较低含水率条件下可加快生物强化好氧稳定化速率,外源菌种影响了降解菌群结构与功能的演替,研究结果可为生物强化技术在填埋场好氧修复工程中的应用提供理论基础和技术支撑。

Aerobic landfill reactor technology is important for accelerating the treatment of municipal solid waste(MSW)and serves as the basis for landfill remediation engineering.To further improve the landfill stabilization rate,this study proposes a microbial-enhanced aerobic landfill technology that combines aeration and inoculation methods.Five simulated landfill reactors were operated under anerobic,aerobic,and varying water content conditions(37.5%,43.9%,46.7% and 52.0%).During the 52-day degradation period,body temperature,weight,MSW water content and organic content were monitored.The microbial structures in the different landfill reactors were analyzed using 16S rDNA sequencing method,and their metabolic functions were predicted based on three databases.The results indicated that the landfill reactors with aeration and inoculation exhibited 6.38% to 25.28% higher organic content degradation compared to the anaerobic landfill reactor.The aerobic degradation process was divided into three stages based on body temperature changes:hightemperature stage,sub-high temperature stage,and stable temperature stage.When comparing degradation efficiency under different water content conditions,the aerobic reactor with low water content(37.5%)demonstrated a higher body temperature and organic content degradation rate,indicating more bio-heat production from microbial degradation activity.Further analysis of microbial diversity revealed that the inoculated microorganisms could survive in the aerobic landfill reactors.The phylum Firmicutes and the genus Sporosarcina,which prefer growing in alkaline environment,dominated the aerobic landfills during the high temperature stage.The predicted metabolic functions mainly included manganese oxidation,chemoheterotrophy,fermentation,and the oxidation of sulfur and nitrogen compounds.Additionally,MSW water content showed a positive linear relationship with the abundance of manganese oxidation functions and a negative relationship with chemoheterotrophy functions.In conclusion,the microbial inoculum can survive in aerobic landfill reactors and accelerate the early stabilization process,especially under low water content(37.5%)conditions.These results provided a theoretical basis and technical support for the microbial enhancement technology in landfill remediation engineering.