过硫酸盐联合硝酸盐处理汽油污染源区地下水:砂槽实验研究  

Treatment of groundwater in gasoline contaminated source area by persulfate combined with nitrate:A sand tank experimental study

作　　者：蒋亚萍[1] 闫嘉宁 陈余道[1] 杨鹏飞 李炜轩 邓旭 邓日添 JIANG Yaping;YAN Jianing;CHEN Yudao;YANG Pengfei;LI Weixuan;DENG Xu;DENG Ritian(Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area,Guilin University of Technology,Guilin 541006)

机构地区：[1]桂林理工大学岩溶地区水污染控制与用水安全保障协同创新中心,桂林541006

出　　处：《环境科学学报》2023年第8期131-140,共10页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金项目(No.41967028);广西自然科学基金重点项目(No.2019JJD150002)。

摘　　要：原位生物修复和原位化学氧化是处理地下水燃油污染的两种有效技术,它们的联合也具有一定的可行性,但相关研究尚很少见.为进一步验证两种技术在水流条件下处理汽油污染地下水中的联合性能,本研究利用两个结构相同的实验砂槽模拟浅层含水层,通过分别投注传统汽油和乙醇汽油(含10%乙醇,体积比),持续补充硝酸盐作为电子受体以促进生物修复作用,以及采用过硫酸盐(Persulfate,PS)作为氧化剂以瞬时投注和连续投注两种方式实施化学氧化处理,研究污染源区主要污染物苯、甲苯、乙苯和二甲苯(BTEX)、PS和硝酸盐的迁移与衰减.结果表明:在持续补充硝酸盐电子受体的条件下,传统汽油和乙醇汽油侵入地下水后BTEX溶解过程均呈现浓度波动期和消退期,BTEX浓度假一级衰减速率常数分别为0.033和0.028 d^(-1),乙醇衰减速率常数为0.166 d^(-1);瞬时投注PS时,传统汽油和乙醇汽油的BTEX浓度假一级衰减速率常数分别为0.056和0.063 d^(-1),比未投注PS时的速率常数大;连续投注PS时,BTEX假一级衰减速率常数分别为0.013和0.014 d^(-1),比前面两种工况下的速率常数小,且对硝酸盐还原作用有轻微的抑制影响.受对流弥散和密度差异的影响,PS与BTEX接触的持久性会降低.研究表明,PS联合硝酸盐处理汽油污染源区地下水是可行的,pH和硝酸盐的利用可作为联合性能判别指标.建议今后进一步开展如何增强PS与BTEX接触持久性的技术研究.In-situ bioremediation and in-situ chemical oxidation are two effective approaches for treating gasoline contamination in groundwater,with their combination being feasible in some cases.However,related research is still rare.To further examine the efficacy of two approaches combined in treating gasoline contaminated groundwater under flow condition,two experimental sand tanks with the same structures were utilized in this study to model an actual aquifer.Traditional gasoline and ethanol gasoline(10% ethanol,V/V)were injected into these two tanks,respectively.Nitrate acted as an electron acceptors,with continuous injection,and persulfate(referred to as PS)acted as a chemical oxidizing agent,with two modes of instantaneous and continuous injections.With these different modes,the fate and transport of aromatics including benzene,toluene,ethylbenzene and xylene(referred to as BTEX)were investigated.The results showed that the dissolution of BTEX experienced fluctuation and attenuation periods in concentration after the injection of gasoline.With the presence of nitrate reduction,the pseudo-first-order decay rate constants of BTEX concentration of traditional gasoline and ethanol gasoline were 0.033 and 0.028 d^(-1),respectively,and the decay rate constant of ethanol was 0.166 d^(-1).In the case of instantaneous injection of PS,the pseudo-first-order decay rate constants of BTEX were 0.056 and 0.063 d^(-1),respectively.These two values decreased to 0.013 and 0.014 d^(-1) in the case of continuous injection of PS.Moreover,the continuous injection of PS could slightly inhibit the activity of nitratereducing bacteria.As a result of advection,hydrodynamic dispersion and variations in density,the persistence of contact between PS and BTEX declined.The combination of PS and nitrate for treating gasoline contaminated groundwater is not only necessary but also feasible.Indicators including pH value,concentration of nitrate and its intermediates are useful to examine the performance of combination.This work also suggests that

关 键 词：传统汽油 乙醇汽油 BTEX 地下水 过硫酸盐(PS) 硝酸盐 联合处理 

分 类 号：X523[环境科学与工程—环境工程]