硫酸盐对污泥高级厌氧消化过程中甲基汞迁移转化的影响  

Effect of Sulfate on the Migration and Transformation of Methylmercury in Advanced Anaerobic Digestion of Sludge

作　　者：何湘琳 刘吉宝[2] 阴永光[2] 谭颖锋 朱爱玲 左壮[3] 高山 解立平[1] 魏源送[2,4] HE Xiang-lin;LIU Ji-bao;YIN Yong-guang;TAN Ying-feng;ZHU Ai-ling;ZUO Zhuang;GAO Shan;XIE Li-ping;WEI Yuan-song(School of Environmental Science and Engineering,Tianjin Polytechnic University,Tianjin 300387,China;Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;Beijing Drainage Croup Co.,Ltd.,Beijing 100192,China;University of Chinese Academy of Sciences,Beijing 100049,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,北京100085 [3]北京城市排水集团有限责任公司,北京100192 [4]中国科学院大学,北京100049

出　　处：《环境科学》2020年第3期1425-1431,共7页Environmental Science

基　　金：北京市自然科学基金项目(8182053);天津市自然科学基金重点项目(18JCZDJC10070);国家自然科学基金青年科学基金项目(51808539);中国博士后科学基金项目(2017M620932)。

摘　　要：为研究污泥高级厌氧消化过程中甲基汞的迁移转化特征以及硫酸盐对污泥厌氧消化过程中汞形态迁移转化的影响,本研究以高温热水解污泥的厌氧消化为研究对象,考察了不同硫酸盐投加浓度下污泥厌氧消化过程中甲基汞的迁移转化特征.结果表明,污泥厌氧消化初期(第1~3 d)发生了汞的甲基化作用,平均甲基汞/总汞比例由0.024%(比值范围为0.019%~0.033%)增加到0.038%(比值范围为0.030%~0.048%),甲基汞净增量分别增加了3.97、 6.09、 0.17、 3.71和1.66倍,随后第3~5 d却发生了明显的汞去甲基化作用,甲基汞净增量降低了71.25%(范围为67.42%~75.10%).硫酸盐对厌氧消化初期汞的甲基化有一定的抑制,而厌氧消化后期,硫酸盐对汞甲基化影响并不明显,这与带电基团HgHS2^-、 HgS2^2-降低了中性汞络合物的生物有效性及铁硫化物、硫化汞等对S^2-和生物可利用态汞的固定作用有关.通过冗余分析,汞的甲基化受到多种环境因素的影响,丙酸、异丁酸和异戊酸等有机质和Fe可能促进汞甲基化,而蛋白质和较高的pH值可能是污泥厌氧消化过程中汞甲基化的抑制因子.To study the migration and transformation of methylmercury during advanced anaerobic digestion of sludge and the role of sulfate, this study investigated the migration and transformation of methylmercury during different stages of sludge anaerobic digestion(AD) with thermal hydrolysis pretreatment and under different dosages of sulfate addition. The results showed that mercury methylation occurred in the initial stage of AD(Day 1-3), the ratio of methylmercury to total mercury increased from 0.024%(range of 0.019%-0.033%) to 0.038%(range of 0.030%-0.048%), and the net increment of methylmercury increased by 3.97, 6.09, 0.17, 3.71, and 1.66 times, respectively. In the following Day 3-5, the demethylation process occurred with the net yield of methylmercury decreased by 71.25%(ranging from 67.42% to 75.10%). Sulfate inhibited the methylation of mercury in the initial stage of AD, but had little effect on it in the late stage. This was related to the reduction of the bioavailability of neutral mercury complexes by charged groups of HgHS2^2- and HgS2^2-, as well as the immobilization of iron sulfide and mercury sulfide on S^2- and bioavailable mercury. Redundancy analysis(RDA) showed that mercury methylation was affected by several factors: organic substances such as propionic acid, isobutyric acid, isovaleric acid, and Fe may promote mercury methylation, whereas protein and higher pH may be inhibitors of mercury methylation in AD of sludge.

关 键 词：污泥 汞 厌氧消化 甲基汞 硫酸盐 

分 类 号：X703[环境科学与工程—环境工程]