污泥堆肥及其利用过程汞的变化特征  

Variation characteristics of mercury during municipal sludge composting and its land use

作　　者：程焱 余亚伟 张成[1] 罗泳楠 张美平 张玉涛[3] 王定勇[1] CHENG Yan;YU Yawei;ZHANG Cheng;LUO Yongnan;ZHANG Meiping;ZHANG Yutao;WANG Dingyong(College ofResources and Environment,Southwest University,Chongqing,400715,China;Wanzhou District Ecological Environment Monitoring Station,Chongqing,Wanzhou,404120,China;Engineering Technology Center of Control and Remediation of Soil Contamination,Anshun University,Anshun 561000,China)

机构地区：[1]西南大学资源环境学院,重庆400715 [2]重庆市万州区生态环境监测站,万州404120 [3]安顺学院土壤污染修复与控制工程技术研究中心,安顺561000

出　　处：《环境化学》2021年第7期2226-2233,共8页Environmental Chemistry

基　　金：国家自然科学基金(51208426,41671469);贵州省科技计划院士工作站项目([2016]5602);贵州省教育厅创新群体重大研究项目(黔教合KY字[2017]049)资助.

摘　　要：以城市脱水污泥为基质,设置两种堆肥处理(含生物炭和不含生物炭),并将堆肥产品和常规氮肥(尿素)进行土地利用,研究污泥堆肥过程及其与氮肥利用过程汞的转化及释放特征。结果表明,污泥堆肥过程能有效降低污泥中的总汞及甲基汞含量,但污泥堆肥施用仍然显著增加了土壤总汞及甲基汞含量,长期施用可能增加土壤环境汞生态风险。土壤汞释放通量呈先升高后降低并逐渐趋于稳定的变化趋势,土壤汞释放集中在污泥堆肥施用后的第1周,约占总释放量的40.6%—69.9%。与对照相比,施用污泥堆肥和氮肥(尿素)均能增加土壤汞的释放量(P<0.05),且施用生物炭堆肥处理土壤汞释放量显著低于施用不含生物炭堆肥处理(P<0.05),说明生物炭的添加可能抑制了堆肥施用后土壤汞的释放。施肥后的前2周,施用含生物炭堆肥处理土壤汞释放量高于氮肥(尿素)处理(P>0.05),2周后却低于氮肥(尿素)处理(P>0.05),表明污泥堆肥施用仅在短期内增加了土壤汞释放量,而氮肥(尿素)的施用促进了土壤汞的释放,且持续时间相对较长。Two different sludge compost products of municipal dewatered sludge(with and without biochar)as well as the regular nitrogen(N)fertilizer(carbamide)were applied in the field.This study was conducted to investigate the variation and emission characteristics of mercury(Hg)during composting and the further land applications of the sludge compost products as well as the regular N fertilizer.Results showed that composting processes could reduce total Hg and methylmercury(MeHg)in sludge matrices.However,the further applications of sludge compost products increased the contents of total Hg and MeHg in soils.Thus,long-term utilization might increase Hg risk in soil systems.It should be noted that Hg fluxes of soils showed similar changes as initial increases,following decreases,and final plateauing phases.The predominant Hg emission was observed in the first week after land application,accounting for approximately 40.6%—69.9%of the total Hg emissions.Compared to the control treatment,application of sludge compost products and regular N fertilizer(carbamide)respectively,both increased the diurnal Hg emission fluxes(P<0.05).Meanwhile,the diurnal Hg emission fluxes from soil applied sludge compost product with biochar were significantly lower than that of the treatment without biochar(P<0.05).This indicated that the addition of biochar could inhibit Hg releases from the soils after the application of sludge compost products.The cumulative Hg emissions from soil applied sludge compost product with biochar were higher than that of the regular N fertilizer(carbamide)in the first two weeks after land application(P>0.05),while it was lower than that of the regular N fertilizer(carbamide)after two weeks of land application(P>0.05).This indicated that the application of sludge compost product only increased the Hg emissions from soil in a short term,while the application of N fertilizer(carbamide)could enhance the Hg emissions from soil in a relatively long term.

关 键 词：汞 甲基汞 汞释放 污泥堆肥 土地利用 

分 类 号：X703[环境科学与工程—环境工程]