低渗透地层中高压旋喷和直压注射工艺修复三氯乙烯污染土壤对比分析——以上海某污染地块为例  

Comparative analysis of high pressure rotary spray and direct pressure injection technologies for remediation of trichloroethylene contaminated soil in low permeability formations:a case study of a polluted site in Shanghai

作　　者：章长松 崔航 ZHANG Changsong;CUI Hang(Shanghai Geology and Mining Engineering Survey(Group)Co.,Ltd,Shanghai 200072,China;Shanghai Yaxin City Construction Co.,Ltd.,Shanghai 200436,China;Technology Innovation Center for Land Spatial Eco-Restoration in Metropolitan Area,Ministry of Natural Resources,Shanghai 200003,China)

机构地区：[1]上海市地矿工程勘察(集团)有限公司,上海200072 [2]上海亚新城市建设有限公司,上海200436 [3]自然资源部大都市区国土空间生态修复工程技术创新中心,上海200003

出　　处：《上海国土资源》2023年第4期154-160,共7页Shanghai Land & Resources

基　　金：国家重点研发计划“低渗透地层原位增渗协同修复智慧决策系统与成套装备”(2020YFC1808105)。

摘　　要：高压旋喷和直压注射原位修复工艺在低渗透地层中的适用性尚缺乏较为系统的理论分析和实践对比。以上海某三氯乙烯(TCE)污染地块为例,从药剂选择、工艺影响半径分析、修复效果等方面论述原位修复工艺的适用性。对比分析零价铁(ZVI)还原技术和活化过硫酸钠(PS)氧化技术,表明活化PS氧化技术成熟度高,修复效果更有保障。引入圆形断面自由紊动射流理论和宾汉姆流体柱形渗流理论分别对高压旋喷工艺和直压注射工艺影响半径进行理论计算,结果表明两种工艺作用半径均受土层性质和工艺参数的影响。当二重管高压旋喷钻喷杆直径为50 mm,喷头直径为2 mm,注射压力为30 MPa,空气压力为0.8 MPa,旋转速度为10 r/min,提升速度为25 cm/min时,在粉质黏土、淤泥质粉质黏土、砂质粉土、淤泥质黏土层中的作用直径均能达到0.9 m以上。直压注射工艺在不同土层中的作用半径差异较大,当注射压力为5 MPa时,在砂性土层中作用半径达到1 m所需时间为0.23 h,而在粉质黏土中所需时间高达120.6 h;将注射压力提高至30 MPa,在粉质黏土中作用半径达到1 m所需时间仍需20.1 h。根据影响半径的理论分析确定修复工艺和参数,结合硫酸亚铁活化PS氧化技术开展TCE污染土壤的修复中试,结果显示土壤中TCE得到显著降解,且修复后残留质量分数低于风险控制值。该研究结果可为高压旋喷和直压注射工艺在低渗透地层污染修复项目中的应用提供理论依据和经验参考。The applicability of high pressure rotary spray and direct pressure injection in situ remediation technologies in low permeability formations lacks a systematic theoretical analysis and practical comparison.Taking a trichloroethylene(TCE)contaminated site in Shanghai as an example,this study discusses the suitability of in situ remediation technologies in terms of agent selection,analysis of process influence radius,and remediation effectiveness.A comparative analysis between zero-valent iron(ZVI)reduction technology and persulfate(PS)activation oxidation technology demonstrates that PS activation oxidation technology is more mature and provides better remediation outcomes.The theoretical calculations of the influence radius for high pressure rotary spray and direct pressure injection technologies are conducted using the theory of circular cross-section free turbulent jets and Buckingham fluid column seepage theory,respectively.The results indicate that both technologies’influence radii are influenced by soil properties and process parameters.For instance,when the dual-pipe high pressure rotary spray drill rod has a diameter of 50 mm,nozzle diameter of 2 mm,injection pressure of 30 MPa,air pressure of 0.8 MPa,rotation speed of 10 r·min-1,and uplift speed of 25 cm·min-1,the influence diameter can exceed 0.9 m in silty clay,silty clay with silt,sandy loam,and muddy clay.The direct pressure injection technology shows significant differences in the influence radius among different soil layers.For example,at an injection pressure of 5 MPa,the time required to achieve a 1 m influence radius in sandy soil is 0.23 h,while it increases to 120.6 h in silty clay.Increasing the injection pressure to 30 MPa still requires 20.1 h to achieve a 1 m influence radius in silty clay.Based on the theoretical analysis of the influence radius,the remediation process and parameters are determined,and a pilot-scale remediation of TCE-contaminated soil is carried out using ferrous sulfate activation of PS oxidation technology.The resu

关 键 词：低渗透地层 高压旋喷 直压注射 影响半径 三氯乙烯 

分 类 号：X53[环境科学与工程—环境工程] X833