甲基汞和腐殖质在污泥堆肥过程中的变化特征及其相互关系  

Research on the changes of methylmercury and humus in sludge and their relationship during aerobic compositing

作　　者：鲍振 刘吉宝[2,3] 李雪怡 王侨 张少博 解立平[1] 魏源送[2,3] BAO Zhen;LIU Jibao;LI Xueyi;WANG Qiao;ZHANG Shaobo;XIE Liping;WEI Yuansong(School of Environmental Science and Engineering,TIANGONG UNIVERSITY,Tianjin,300387,China;State Key Joint Laboratory of Environmental Simulation and Pollution Control,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing,100085,China;Department of Water Pollution Control Technology,Research Center for EcoEnvironmental Sciences,Chinese Academy of Sciences,Beijing,100085,China;Beijing Shouchuang Sludge Disposal Technology Co.,Ltd,Beijing,100044,China)

机构地区：[1]天津工业大学环境科学与工程学院,天津300387 [2]中国科学院生态环境研究中心,环境模拟与污染控制国家重点联合实验室,北京100085 [3]中国科学院生态环境研究中心,水污染控制实验室,北京100085 [4]北京首创污泥处置技术有限公司,北京100044

出　　处：《环境工程学报》2022年第7期2326-2334,共9页Chinese Journal of Environmental Engineering

基　　金：国家重点研发计划项目(2019YFC1906502);天津市自然科学基金重点项目(18JCZDJC10070)。

摘　　要：好氧堆肥-土地利用是实现污泥资源化处置的主要方式,但污泥中重金属的环境健康风险是限制污泥土地利用的重要因素。通过观测北方某工程规模的污泥好氧堆肥过程汞、甲基汞的变化,并基于三维荧光光谱区域积分分析,研究好氧堆肥过程甲基汞的变化特征及其与有机物中腐殖质变化关系。结果表明,堆肥前后,汞与甲基汞质量分数未发生明显变化,但通过质量衡算发现,堆肥结束后堆体中汞总量从(272.56±25.71) g下降到(211.10±12.97) g,出现22.5%的汞散失,而甲基汞质量从0.37 g下降至0.28 g,24.3%的甲基汞可能发生去甲基化而形态转变。在堆肥过程中,甲基汞质量与荧光区域Ⅲ(富里酸)体积积分呈显著负相关(r=-0.897,p<0.05),与荧光区域Ⅳ(微生物代谢副产物)体积积分呈显著正相关(r=0.933,p<0.01)。基于堆肥过程甲基汞和汞质量的动态变化,在堆肥前10 d的有机物快速腐熟化阶段发生了甲基汞的去甲基化,而后随好氧堆肥过程翻堆、曝气发生了汞的蒸发散失。本研究结果可为评价污泥好氧堆肥后对汞、甲基汞健康风险提供参考。Aerobic composting followed by land application is the main process for resources recovery from sewage sludge, but the environmental health risk of heavy metals limits the land application of sludge. By sampling and analyzing the mercury(Hg) and methylmercury(MeHg) contents in sludge during one full-scale aerobic composting plant in north China, this study investigated changes of MeHg and its relationship with humus based on three-dimensional fluorescence spectroscopy(3D-EEM) combined with integration analysis.Results showed that there was no obvious difference in the contents of Hg and MeHg before and after composting. According to the mass balance calculation, Hg amount was reduced from 272.56±25.71 g to211.10±12.97 g, i.e., 22.5% of Hg was lost. And the amount of MeHg was reduced from 0.37 g to 0.28 g. 24.3%of MeHg was demethylated. Changes of humus during compost revealed that the initial phase of composting(10days) was the fast humification period. Aromatic protein and soluble microbial byproduct were biodegraded fast,and accordingly, humic and fulvic substances increased. The amount of MeHg was significantly negatively related with the integral fluorescence intensity of region III(fulvic acid)(r=-0.897, p<0.05), and significantly positively related with the integral fluorescence intensity of region IV(microbial metabolic byproducts)(r=0.933, p<0.05). Based on the dynamic changes of MeHg and Hg contents during aerobic composting,demethylation of MeHg occurred during the fast humification period in early 10 days, and Hg loss happened in the subsequent aerating and turning process. The results of this study can provide a reference for monitoring the health risks of Hg and MeHg after aerobic composting.

关 键 词：污泥 好氧堆肥 汞 甲基汞 腐殖质 

分 类 号：X705[环境科学与工程—环境工程]