原位激发微生物矿化处理铅污染土的工程特性与环境安全性研究  

Engineering properties and environmental safety of biostimulated MICP-treated lead-contaminated soil

作　　者：张宇[1] 张庆[1] 王逸杰 蔡国军 董晓强[4] 杜延军[1] 蒋宁俊[1] ZHANG Yu;ZHANG Qing;WANG Yijie;CAI Guojun;DONG Xiaoqiang;DU Yanjun;JIANG Ningjun(Institute of Geotechnical Engineering,Southeast University,Nanjing 211189,China;Department of Civil and Environmental Engineering,The Hong Kong Polytechnic University,Hong Kong 999077,China;School of Civil Engineering,Anhui Jianzhu University,Hefei 230601,China;College of Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]东南大学岩土工程研究所,江苏南京211189 [2]香港理工大学土木及环境工程学系,中国香港999077 [3]安徽建筑大学土木工程学院,安徽合肥230009 [4]太原理工大学土木工程学院,山西太原030024

出　　处：《岩土工程学报》2024年第11期2352-2360,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(42007246);东南大学新进教师科研启动经费资助项目(RF1028623197)。

摘　　要：随着城市化进程的加速,重金属污染场地的修复、开发和再利用日益受到社会关注。以典型重金属污染物铅为研究对象,利用原位激发微生物矿化方法探究了铅浓度对土壤酸碱度、活菌数以及尿素和铵根浓度等细菌活性指标的影响,通过测试固化土的无侧限抗压强度、渗透系数和毒性浸出浓度,评估了铅污染土的固化效果。结果表明,原位激发方法可以实现低铅浓度污染土中脲酶菌的富集,激发7d后土中活菌数最高可达到10^(9)CFU/g数量级,但高浓度的铅污染物将显著抑制微生物的生长与活性。原位激发MICP处理铅污染土的强度和防渗性均随固化时间呈增长趋势,其中40mM铅污染土固化14d的强度大幅提高,渗透系数可降低至6.5×10^(-6)m/s。铅的浸出浓度随固化时间均不断降低,低铅浓度污染土固化14 d后在中性或弱酸性环境下的浸出浓度可低于0.1 mg/L。根据固化铅污染土的工程特性与环境安全性试验结果,结合环境扫描电镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)和微生物16 s全基因组重测序等手段,揭示了原位激发微生物矿化处理铅污染土的固化机理。With the acceleration of urbanization,the remediation,development and reuse of heavy metal-contaminated sites have attracted increasing attention.Taking the typical heavy metal contaminant lead as the research object,the effects of lead concentration on the bacterial activity indexes such as pH of soil,number of viable cell,concentration of urea and ammonium are investigated by using the biostimulated MICP method.The unconfined compressive strength,permeability and toxicity leaching concentration of the solidified lead-contaminated soil are used to evaluate the solidification effects.The findings demonstrate that the biostimulation method can realize the enrichment of ureolytic bacteria in low lead concentration contaminated soils.The number of viable cell can reach 10^(9) CFU/g after 7 days of enrichment,but the high concentration of lead contaminants significantly inhibits the growth and activity of microorganisms.The strength and impermeability show an increasing trend with solidifying time,and the strength of 40 mM lead-contaminated soil increases significantly and the permeability coefficient can be decreased to 6.5×10^(-6) m/s after solidifying for 14 days.The leaching concentration also decreases with solidifying time,and the leaching concentration of the low lead concentration-contaminated soil solidified for 14 days can be lower than 0.1 mg/L in neutral or weakly acidic environment.Based on the engineering properties and environmental safety tests,the solidification mechanism of the lead-contaminated soil treated by the biostimulated MICP is revealed by combining the scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD)and microbial 16 s whole genome resequencing.

关 键 词：原位激发 微生物诱导碳酸钙沉淀 铅污染土 工程特性 环境安全性 

分 类 号：TU43[建筑科学—岩土工程]