【作者】 孙威；

【导师】 赵勇胜；

【作者基本信息】 吉林大学 ， 环境工程， 2012， 博士

【摘要】 地下水作为重要的淡水资源，与人类的生活是息息相关的。但是近些年来，由于地下水的不合理开发利用、污染物的过度排放和一些突发性污染泄漏事件，造成了地下水的严重污染。而苯类有机物是地下水中比较常见的一类污染物，其中苯、甲苯、乙苯、二甲苯（BTEX）和硝基苯是石油行业中重要的原材料，在石油及其衍生产品的运输、使用、生产等环节造成的泄漏和渗漏现象，均能够引起地下环境中苯类有机物的污染问题。地下环境中的苯类污染物以非水相液体（NAPL）形式存在，BTEX属于轻非水相液体（LNAPL），硝基苯属于重非水相液体（DNAPL），均是毒性较强的污染物，具有“致癌、致畸、致突变”作用，它们一旦进入到地下水中，对人类的健康将产生极大的威胁。所以关于地下水中苯类有机物污染的控制与修复引起人们越来越广泛的关注。控制和治理地下水中苯类有机物污染的方法有很多，如抽出-处理法、原位化学法、空气扰动法、微生物处理法、可渗透反应墙方法等，这些修复技术各有优势，但是也有不足，有些方法对污染场地的适应性较差、有些方法修复费用较高、有些方法对环境干扰较大等。原位反应带修复技术（IRZ）是近些年发展起来的一种新型原位修复手段。该技术能够最大程度地减少污染物的暴露以及对环境的扰动，具有修复效果好、投资少、见效快，并且施工简便等优点，因此该修复技术应用前景非常广阔。本研究在综合国内外文献的基础上，将原位反应带修复技术应用到地下水苯类有机污染物的控制和处理当中，选择较难修复的BTEX和硝基苯作为目标污染物。通过系列实验考察芬顿试剂对地下水中BTEX污染的氧化去除效果，并对各种影响因素进行对比分析，确定最佳处理工艺条件；探讨地下水流速、地下介质类型等因素对原位反应带修复技术的影响；并对地下含水层中的BTEX污染采用原位反应带技术进行修复研究。另外通过系列实验考察淀粉改性纳米铁浆液对硝基苯污染的还原处理效果，并进行影响因素对比分析，确定最佳处理工艺条件；探讨地下水流速、地下介质类型等因素对原位反应带技术修复硝基苯污染的影响，并探讨硝基苯还原产物苯胺的原位微生物反应带的去除效果；采用原位化学反应带和原位微生物反应带联合技术对地下含水层中的硝基苯污染进行修复研究。本课题的创新点体现在：（1）采用原位反应带技术应用于地下水中苯类有机污染物的修复，通过注入井将反应试剂注入到污染晕中，形成有效的原位反应带，对污染物进行去除处理，同时研究了水文地质因素对原位反应带技术修复效果的影响，得出具体工艺参数，为修复污染场地提供技术参考。该方法最大限度的减少对环境的扰动，克服了PRB等原位修复技术对污染土体开挖的不足。（2）采用淀粉作为纳米铁的修饰材料，制成包覆形纳米铁，使用淀粉改性纳米铁浆液对地下水中的硝基苯污染物进行还原处理，总结出影响实验效果的具体工艺参数，并在此基础上对地下含水层中的硝基苯污染进行了原位化学还原反应带修复实验研究。该项研究成果已经申报并获得了国家发明专利。（3）摸索了将芬顿试剂注入到模拟含水层中，形成的原位化学氧化反应带对BTEX污染进行氧化的去除效果，确定具体的工艺影响参数，并在此基础上进行了BTEX污染原位反应带修复的影响因素研究，为应用芬顿试剂原位反应带技术修复污染地下环境的工程实践奠定了基础。通过系列实验研究了芬顿试剂作为修复地下水中BTEX污染反应试剂的去除效果，确定BTEX污染处理的最佳工艺参数，研究结果表明，①在反应体系中过氧化氢的浓度越大，地下水中的BTEX去除效果越好；②在过氧化氢与BTEX摩尔比相同的条件下，过氧化氢与二价铁离子摩尔比越小，即体系中Fe2+的含量越多，BTEX的去除效果越好，但是如果二价铁离子的含量过多，反应体系中的沉淀量增多，影响BTEX的去除效果；③当过氧化氢与二价铁离子的摩尔比为8时，BTEX的平均去除效率均能达到90%以上，此时体系pH由初始的6～7迅速降低至3左右，ORP由初始的-44mV迅速增加到450～500mV范围内，反应体系属于强氧化的环境；④BTEX的氧化去除过程均符合二级动力学方程。在对原位化学氧化反应带影响因素的研究中，采用水平放置的模拟柱模拟地下水中的BTEX污染状况，通过注入井注入芬顿氧化试剂，考察水文地质因素对芬顿试剂形成的原位反应带氧化处理BTEX的影响，研究结果显示：①注入的芬顿试剂能够在模拟柱中形成有效的原位化学氧化反应带，氧化去除污染物BTEX；②各取样口BTEX的去除率距离注入井口越近，去除率越大，而且各个取样口BTEX浓度呈现依次降低，然后再依次升高的趋势；③地下水流速较大时（0.33m/d），在模拟柱运行的前期，BTEX的去除效果较好，而在运行后期，地下水流速（0.11m/d）较小的模拟柱中BTEX的去除效果较好；④芬顿氧化试剂在注入总量相同的情况下，两次注入时BTEX的去除效果比单次注入时好；⑤由于地下介质类型不同，介质孔隙度大小不同，形成的原位反应带对BTEX氧化去除率保持时间也不相同，粗砂中反应带去除BTEX维持高效的时间较细砂短；⑥模拟柱在注入芬顿氧化试剂后，反应体系内各取样口的ORP均有不同程度的上升，而pH均有不同程度的下降，反应体系处于酸性氧化环境。利用自制纳米铁浆液、金属铜改性纳米铁浆液和淀粉改性纳米铁浆液，对地下水中的硝基苯进行还原处理，实验结果表明零价铁的不同形态对地下水中硝基苯的还原效果影响很大，采用0.8%淀粉改性纳米铁浆液时，硝基苯的还原率可达100%，苯胺的转化率达83.33%，而且改性纳米铁浆液还原处理硝基苯的过程符合一级动力学方程㏑C=-0.7623t+0.3469。通过水平放置的模拟柱模拟地下水中的硝基苯污染，采取注入的方式将淀粉改性纳米铁浆液注入到地下水环境中，形成了有效的原位化学还原反应带，还原去除地下水中的硝基苯污染，取得较好效果。研究结果表明：①当地下水流速和注入淀粉改性纳米铁浆液的浓度相同时，含水层介质是粗砂，硝基苯的还原效率为84.15%，苯胺的转化率为28.48%；含水层介质是细砂，硝基苯的还原效率为82.98%，苯胺的转化率为26.39%；②当地下水流速和含水层介质类型相同，注入的淀粉改性纳米铁浆液的浓度为18.0g/L时，硝基苯的还原效率为84.15%，苯胺的转化率为28.48%；注入的淀粉改性纳米铁浆液的浓度为5.0g/L时，硝基苯的还原效率为92.98%，苯胺的转化率为36.84%；③当含水层介质类型和注入的淀粉改性纳米铁浆液浓度相同时，地下水流速(0.1m/d)较小时，硝基苯的还原效率为84.15%，苯胺的转化率为28.48%；地下水流速（0.4m/d)较大时，硝基苯的还原效率为42.79%，苯胺的转化率为22.17%。可见当含水层介质是粗砂、地下水流速较小、注入的淀粉改性纳米铁浆液的浓度较小时，硝基苯的还原效果最好，苯胺的转化率最高。通过在模拟柱中加入营养盐，形成原位微生物反应带，强化苯胺的自然衰减作用实验，为原位化学反应带和原位微生物反应带联合去除硝基苯和产物苯胺提供理论依据。研究结果表明在模拟柱中加入营养盐，能够激活体系中的土著微生物，当碳、氮、磷的比例为100:5:1时，激活的土著微生物能够有效降解去除苯胺，苯胺的最大去除率接近100%。为进一步探索应用原位反应带技术修复BTEX污染的地下含水层的具体工艺参数，采用模拟槽模拟地下含水层，研究结果发现污染物质BTEX进入含水层后，形成污染晕，开始时污染晕集中在注入井周围的含水层顶部，然后逐渐向下游迁移扩散，污染晕中的污染物BTEX的浓度自上而下渐次递减。当污染源污染含水层22小时之后，监测到BTEX在含水层中形成了全面污染晕。污染晕形成后，从注入井注入芬顿试剂，在含水层中形成芬顿试剂原位反应带；在实验装置运行期内，监测到污染物BTEX的浓度逐渐减小，污染物E（乙苯）的平均去除率达到100%，BTX的平均去除率也能够达到95%以上。适时监测实验装置各取样口水中的pH和DO值的变化情况，结果显示在注入芬顿试剂后，各取样口溶解氧值均有不同程度的升高，平均值由原来的2.00mg/L迅速上升到20.00mg/L左右。各取样口的pH由原来的pH=7均产生不同程度的降低。在利用原位化学反应带和原位微生物反应带技术联合修复地下含水层中硝基苯污染的研究中，从注入井将淀粉改性纳米铁浆液注入到含水层中，形成原位化学反应带，能够对地下含水层中的硝基苯污染产生良好的修复效果，硝基苯的平均还原率为53.72%～69.75%，苯胺的平均转化率为3.25%～33.20%；在含水层中注入营养盐后，能够将部分土著微生物激活，形成原位微生物反应带，不仅增大了硝基苯还原产物苯胺的降解效率，同时对硝基苯的去除效果也产生影响。含水层中的pH均较初始pH大，DO值也维持在高于初始水平的基础上，反应体系呈现弱碱性的厌氧环境。更多还原

【Abstract】 As an important freshwater resource, groundwater is closely related to humanlife. But in recent years, impertinency exploitage and utilization of groundwater,pollutant emissions and unexpected pollution spill, brought serious pollution togroundwater. While organic-benzene, including benzene, toluene, ethylbenzene,xylene（BTEX） and nitrobenzene, are important raw materials in the oil industry,they are common groundwater pollutants as well, which in oil and its derivativestransporting, could lead to benzene organic pollution by leaks and leakage in usage,production and other sectors. Benzene-based pollutants exist a Non-aqueous PhaseLiquid (NAPL) in Underground environment.BTEX belongs to light Non-aqueousPhase Liquid (LNAPL), nitrobenzene belongs to dense Non-aqueous Phase Liquid(DNAPL), they are more toxic pollutants strong, they can cause "cancer, teratogenicand the mutation" effect.Both BTEX and nitrobenzene are highly toxic pollutants andgreat threats to human health once entered into the groundwater. Therefore, thecontrol and remediation of organic-benzene pollutants in groundwater draws a lotmore widespread attention.There are indeed various groundwater treatment techniques, including out-processing method, in-situ oxidation, air sparging, bioremediation and passivetreatment walls. These techniques have their own advantages, but there are certainshortcomings: adaptability of contaminated sites, high cost of remediation andinterference on the environment. The in-situ reaction zone remediation (IRZ) is anewly developed in-situ remediation techniques. This technique can minimizeexposure of pollutants and environmental disturbance, and in respect of its effectiveremediation, fewer investment and easy construction, this technique has a lotpromising applications.On the basis of a large number of domestic and foreign literatures, we apply theIRZ technique on the remediation of underground organic-benzene pollutants, takenthe relatively scabrous BTEX and nitrobenzene as the target pollutants. In this study,we investigated a series of experiments on BTEX contaminated groundwater to examine oxidizing-remediation effect of Fenton’s reagent; various factors were alsoanalyzed to determine the best treatment conditions; we investigate the influence ofgroundwater flow, subsurface lithology and other factors on in-situ reaction zonetechnique with an actual apply in remediating underground aquifer contaminated byBTEX. In addition, we did a series of experiments to examine the reduction effect ofnitrobenzene pollution by starch-modified nano-ferrite slurry, analyzed influencingfactors and comparative analysis to determine the best treatment conditions; exploredgroundwater flow, subsurface lithology and other influential factors in remediatingnitrobenzene pollutants, and explored the in-situ microbial reaction with nitrobenzenereduction products of aniline removal efficiency; use both in-situ chemical andmicrobial reaction zone techniques to remediate nitrobenzene contamination inunderground aquifer.The subject innovation is reflected in:(1) apply in-situ reaction zone technique to the remediation of groundwaterorganic-benzene pollutants, which formed effective in-situ reaction zone by injectingactive reagent into the pollution halo through injection well. The influence of hydrogeological factors on IRZ technique was also studied, coming up with a set of specificprocess parameters for technical reference for the restoration of contaminated sites.This method minimizes the disturbance to the environment, and overcome thedeficiencies of the PRB remediation techniques on excavation of contaminated soil.(2) Use starch as nano-ferrite modification material to facture coated-shapednano-ferrite, with which, deoxidized groundwater nitrobenzene pollutants. On thebasis of a series experiments, we concluded a set of technologic parameters, furthermore, research into aquifer nitrobenzene pollution.(3) Forming in-situ oxidation reaction zone by injecting Fenton’s reagent intogroundwater, oxidized BTEX pollutants, determined the effective parameter, andapplied to the remediation of BTEX contaminated aquifer.We did a series of experiments to study the removal effect of Fenton’s reagentand determined the optimal experimental parameters on the processing of BTEXcontamination. The result shows that①in the reaction system, the hydrogen peroxideconcentration higher, the oxidative capacity greater, and the removal effect of BTEXcontamination better; hydrogen peroxide and BTEX molar than being the same,②westudied the oxidation effect of BTEX contaminants in the groundwater under four conditions of when hydrogen peroxide and ferrous ion molar than were1,4,8and10respectively. We found out that hydrogen peroxide and ferrous ion molar than thesmaller, i.e. more of Fe2+, removal effect of BTEX is better, but too much Fe2+couldgreatly increase precipitation amount, recede BTEX removal efficiency.③The resultshows that the average BTEX removal efficiency all can achieve90%a bove Whenthe hydrogen peroxide and two price of iron ion mole ratio to8. The pH of systemfrom initial of6~7quickly reduced to3or so, by the ORP initial-44mV rapidlyincreased to450~500mV range, strong oxidation reaction system belong to theenvironment;④Theprocess of BTEX oxidation removal conform to the secondarydynamic equation.BTEX pollutants were simulated in a horizontal cuvette, in which various hydrogeological factors influencing in-situ reaction zone oxidizing BTEX effect wereinvestigated by Fenton oxidizing reagent injected through the injection well. Resultsshow that①the injected Fenton reagent could form effective in-situ chemicaloxidation zone to degrade BTEX pollutants.②Degradation residue of BTEXpollutants in each sampling is less where closer to the injection wellhead.③In theearly stage, the removal effect of BTEX is better when groundwater velocity is high(0.33m/d) while in the latter stage, better when the velocity is lower (0.11m/d).④Injected the same amount, Fenton oxidizing reagent performs better when injectedtwice rather then once.⑤Taken subsurface lithology into account, the reacting zonemaintaining time varies due to different medium pores—shorter on the grit than on thefine sand.⑥The ORP value of the sampling ports increases after injected Fentonoxidizing reagent; pH values declines diversely. The reaction system exhibits anacidic aerobic environment.With self-made nano-ferrite slurry, copper-modified and starch-modifiednano-ferrite slurry, we deoxidized nitrobenzene in groundwater. Experiments showthat different forms of zero-valent ferrite have a huge influence on nitrobenzenedeoxidization. Starch-modified nano-ferrite(0.8%) slurry deoxidized100%nitrobenzene and has the83.33%conversion of aniline.And the process ofnitrobenzene modified iron nanoparticles grout reduction treatment correspond1dynamic equation㏑C=0.7623t+0.3469.With horizontal cuvette simulating groundwater pollution status of nitrobenzene, and through the injection of starch-modified nano-ferrite slurry injected into thegroundwater environment, we got a pretty good effective in-situ reacting zone todeoxidize nitrobenzene in groundwater. Different hydro geological factors on theformation of starch-modified nano-ferrite slurry that deoxidizing nitrobenzene wereexamined and the results show that①The rate of nitrobenzene was92.98%and36.84%conversion of aniline When aquifer medium is coarse sand, injection of starchmodification of iron nanoparticles slurry concentration(5.0g/L);②The ratenitrobenzene was42.79%and22.17%conversion of aniline, when aquifer medium iscoarse sand, groundwater flow rate (0.4m/d) larger conditions,③the reduction ofnitrobenzene rate was82.98%,26.39%conversion of aniline,the local water flow(0.1m/d), aquifer medium is coarse sand. The result show that aquifer medium iscoarse sand of modified starch, injecting slurry concentration of iron nanoparticlesmore hours, the reduction of nitrobenzene best effect of aniline conversion rate is thehighest.By adding nutrients into the simulating cuvette, in-situ microbial reaction zonewas formed and strengthened the effect of aniline natural attenuation, which provide atheoretical basis for the joint of in-situ chemical reaction with in-situ microbialreactions in remediating the nitrobenzene and products of aniline. The results showthat the nutrients-added simulating cuvette can activate the indigenousmicroorganisms and when carbon, nitrogen, phosphorus has a ratio of100:5:1, theactivated indigenous microorganisms can effectively degrade the removal of aniline tonearly100%. The mercuric chloride biological inhibitors added are to inhibitmicrobial growth.On the research of in-situ reaction technique on remediating BTEX pollutants,we found that when BTEX entered into the aquifer, they formed a pollution halo, firstconcentrated at the top, around the injection well and then gradually to downstream.The diffusion of BTEX pollutant concentration in contaminated halo is graduallytop-down decreasing.22hours after the pollution, a comprehensive pollution halo ofBTEX in the simulation slot was identified. Then we injected Fenton’s reagentthrough the injection well, which formed in-situ Fenton’s reagent reaction zone in theaquifer. Experiments validate the gradual decrease of BTEX concentration; pollutantE (the ethyl benzene) removal efficiency can reach100%; BTX removal efficiencycan also reach above95%. Changes of pH and DO values in each sampling revealed that when injected Fenton’s reagent, dissolved oxygen values were diversely higher,from the average of2.00mg/L quickly rose to20.00mg/L or so, while pH value ofeach sampling were diversely lower compared with the original degree of7.The technique of in-situ reaction zone in remediation of groundwaternitrobenzene pollution is to form in-situ chemical reaction zone by injectingstarch-modified nano-ferrite slurry through injection well, which has pretty effect onthe remediation of nitrobenzene pollution in the aquifer, with the data of nitrobenzenedeoxidization53.72%～69.75%and aniline conversion3.25%～33.20%. Whennutrients injected into the aquifer, part of the indigenous microorganisms wereactivated and formed in-situ microbial reaction zone, which increased the degradationefficiency of nitrobenzene and affected aniline degradation. The pH and DO value inthe aquifer was both higher, and the reaction system exhibits a weak alkalineanaerobic environment.更多还原