Application research of enhanced in-situ micro-ecological remediation of petroleum contaminated soil

Experimental study of enhanced in-situ micro-ecological remediation of petroleum contaminated loess soil was carried out in Zhongyuan oil production areas, and the enhanced in-situ micro-ecological remediation technique includes optimistic in-situ microbial communities, physical chemistry methods, alfalfa planting and regulation of soil environmental elements. Experiments showed that the oil content in the contaminated soil with oil content about 2 898.25 mg/kg can be reduced about 98.61% after in-situ micro-ecological remediation for 99 days, which demonstrated the effectiveness of in-situ micro-ecological remediation methods for petroleum contaminated soil in central plains of China, and explored the practical and feasible application of these methods.

Applications of Water Sensitivity In Situ Remediation at Saltwater-Freshwater Interface

Based on the laboratory experiments with the saltwater and freshwater replacing each other in the level sand column, taking the kaolin, illite, smectite, bivalent hydrargyrum ion （Hg^2＋） and ＂phenol （C6H5OH） as examples, this paper studies the applications of water sensitivity in situ remediation in saltwater-freshwater transition zone. In the water sensitivity process, the release and migration of clay minerals can make the hydraulic conductivity （HC） decrease and pollutants remove. A new type of low penetrable or impenetrable purdah can be built by adding clay minerals into the sand media to replace the underground concrete impenetrable wall to prevent seawater intrusion, and a number of the heavy metals and organic pollutants in the sand media can be removed by in situ remediation. The results show that the content of kaolin and illite influences the water sensitivity process slightly, and HC of the sand columns descends from 0.011 cm/s to 0.001 4 cm/s and 0.001 2 cm/s respectively even if the content reaches 12% （weight ratio, sic passim）. However, for smectite, HC descends sharply to about 1 × 10^-8 cm/s when its content reaches 4%, and no water can flow through the sand columns beyond 5%. The particle release and migration processes can remove the Hg^2＋ and C6HsOH out of the sand columns efficiently, the removing rate of Hg^2＋ is 31.68% when the freshwater and saltwater are filtered through the sand columns polluted by Hg^2＋, while it is 67.55% when the water sensitivity occurs. With the same method, the removing rates of C6H5OH under the fluid flow and water sensitivity are 55.71% and 43.43% respectively.

Engineering application of ecological remediation technologies in situ treatment of black-odour river

In order to study the remediation technology and effect of the black-odour water bodies,the treatment project of typical black-odour river was taken as an example,and the technical measures,such as sediment dredging,aeration,adding microbial preparation and constructing ecological floating bed,were adopted to treat and restore the water body.The results showed that the black and odorous phenomenon of the river had been basically eliminated and the water quality had been significantly improved after the 9-week operation.The highest removal rates of COD,NH3-N and TP were 82.5%,77.6%and 81.4%,respectively,and the water quality was improved from inferior class V to class IV.The engineering practice indicated that the technical scheme was feasible and could effectively remove the pollutants such as organic matters,ammonia nitrogen and total phosphorus in the water,which could provide basis and reference for the treatment project of similar black-odour water body.

Tracer Testing Strategies for Effective Design and Implementation of in Situ Groundwater Remediation

The effectiveness of an injection-based remediation strategy is primarily governed by accurate understanding of reagent delivery and ensuring uniform distribution within the reactive zone. In IRZ （in situ reactive zone） design, the required reagent strength, injection volumes, injection rates, injection frequency, injection and monitoring well spacing, and the cost and time to achieve remediation goals are governed by the hydrogeology of the site. A properly designed tracer test is capable of providing critical above mentioned site-specific information, to assist with full scale design of an IRZ. This paper describes that implementing tracer testing to support remedial design can result in enhanced design efficiency, added assurance in full-scale implementation and ultimately resulted in substantial cost savings. Therefore, it is recommended that the broader practitioner community adopt this technique as a best practice for effective and optimum in situ remediation system design.

Advances in Microbial Fuel Cells in the Field of Environmental Remediation

In order to protect ecological environment,it is urgent to restore the polluted environment. Among traditional methods of environmental remediation,it is common to add excessive electron donors or electron acceptors to the polluted environment,but these methods have a high cost and can cause secondary pollution easily. Microbial fuel cells( MFCs) can realize the transformation of pollutants and collection of electric energy by using microorganisms as a catalyst; they are clean,efficient and controlled easily and have a wide range of application,so MFCs have wide application prospects in the field of environmental remediation. In this study,MFCs and their applications in the field of environmental remediation were summarized.

热强化气相抽提联合微生物降解技术在加油站场地修复中的应用

以某加油站石油烃污染场地修复工程为案例,根据场地污染状况和修复要求,采用热强化气相抽提联合微生物降解技术进行原位修复。修复区域设置10口抽提井,5口注入井和8口监测井。首先应用气相抽提技术除去土壤中的挥发性有机物,修复20 d后,场地石油烃浓度低于国家标准GB 36600第二类用地筛选值;然后进行热强化气相抽提操作,将土壤中部分半挥发性有机物抽提出来;最后向土壤中注入高效降解菌,进一步除去土壤中残留的污染物,生物降解进行45 d后,土壤石油烃浓度低于第一类用地筛选值,实现修复目标。修复结果表明,该联合修复技术高效、绿色,修复过程可为同类场地修复提供工程借鉴。

In-situ polymerization for PPy/g-C_3N_4 composites with enhanced visible light photocatalytic performance

Polypyrrole‐modified graphitic carbon nitride composites(PPy/g‐C3N4)are fabricated using an in‐situ polymerization method to improve the visible light photocatalytic activity of g‐C3N4.The PPy/g‐C3N4 is applied to the photocatalytic degradation of methylene blue(MB)under visible light irradiation.Various characterization techniques are employed to investigate the relationship between the structural properties and photoactivities of the as‐prepared composites.Results show that the specific surface area of the PPy/g‐C3N4 composites increases upon assembly of the amorphous PPy nanoparticles on the g‐C3N4 surface.Owing to the strong conductivity,the PPy can be used as a transition channel for electrons to move onto the g‐C3N4 surface,thus inhibiting the recombination of photogenerated carriers of g‐C3N4 and improving the photocatalytic performance.The elevated light adsorption of PPy/g‐C3N4 composites is attributed to the strong absorption coefficient of PPy.The composite containing 0.75 wt%PPy exhibits a photocatalytic efficiency that is 3 times higher than that of g‐C3N4 in 2 h.Moreover,the degradation kinetics follow a pseudo‐first‐order model.A detailed photocatalytic mechanism is proposed with·OH and·O2-radicals as the main reactive species.The present work provides new insights into the mechanistic understanding of PPy in PPy/g‐C3N4 composites for environmental applications.

10 Towards a Safer Environment:(7)How apatite minerals remediate Pb,Zn and Mn from wastewater?

To evaluate the effectiveness of apatite mineral in removing different contaminants from low quality water in the industrial city of abha,Asir region,southwestern of Saudi Arabia two phosphatic clay dominated by apatite mineral were selected.In situ remediation experiment proved that apatite mineral has the highest affinity for Pb and removed more than 94% from initial Pb concentration.The rest of contaminants followed the descending order of:Zn>Mn>Cu>Co>Ni.The sorption of Pb,Zn and Mn onto apatite mineral was well characterized by the Langmuir model.Ternary-metal addition induced competitive sorption among the three metals,with the interfering effect of Pb>Zn>Mn.During metal retention by apatite mineral calcium and phosphate were determined in equilibrium solution.Calcium increased and phosphate decreased with increasing metal disappearance.The greatest increase of calcium and the largest phosphate reduction were found with Pb+2 sorption. This is suggested that Pb+2 retention by apatite was through the dissolution of apatite which mean release of Ca and P into solution and formation of pyromorphite(lead phosphate)as consuming of P.Obtained results suggested that there are two general mechanisms for the ability of apatite mineral to take up Pb2+,Zn+2 and Mn+2.The first is (ion-ion exchange mechanism)concerned with adsorption of ions on the solid surface followed by their diffusion into apatite mineral and the release of cations originally contained within apatite.The second is (dissolution- precipitation mechanism)concerned to the dissolution of apatite in the aqueous solution containing Pb2+,Zn+2 and Mn+2 followed by the precipitation or coprecipitation.Pb+2 desorption responding to solution pH may indicate that not all the Pb+2 was chemisorbed and fraction of Pb+2 was weakly adsorbed or complexed on the surface of apatite mineral.

Distribution of Colloidal and Powdered Activated Carbon for the <i>in Situ</i>Treatment of Groundwater

The use of in situ technologies for the treatment of groundwater containing various compounds of concern are widely accepted. These technologies include chemical reduction, chemical oxidation, anaerobic and aerobic bioremediation, and adsorption, among others. One requirement for the successful application of these technologies is the delivery of the remedial reagent(s) to the compounds of concern. A rapidly evolving in situ technology is the injection of adsorptive media such as activated carbon and ion-exchange resin including powdered or colloidal activated carbon. Activated carbon has a long-demonstrated history of effectiveness for the removal of various organic and inorganic compounds in above ground water treatment systems. However, due to constraints related to the particle size and physical properties of the activated carbon, the in situ application of activated carbon has been limited. Recent developments in the manufacturing of activated carbon have created a smaller particle size allowing activated carbon to be applied in situ. To evaluate if powdered and colloidal activated carbon can be effectively distributed in aquifers, the two types of carbon were injected using direct push technology adjacent to each other at four sites with varying geology. Evaluation of distribution was completed by sampling the aquifer prior to and post-injection for total organic carbon. The results of the studies indicated that both forms of activated carbon were effectively delivered to the targeted injection zones with both carbon types being detected at least seven meters away from the point of injection. The colloidal form of the activated carbon showed good distribution throughout the four targeted zones of injection with 93 percent of the samples collected having colloidal activated carbon present within them whereas the powdered activated carbon cells were more susceptible to aquifer heterogeneity with only 67 percent of the samples collected having activated carbon present. Preferential accumulation of activated carbon was observed in high horizontal hydraulic conductivity seams, especially within the powdered activated carbon cells. These results suggested that the powdered form of activated carbon was more suspectable at the four sites to heterogeneity within the aquifer than the colloidal form of activated carbon. Sampling of monitoring well screens installed prior to the injection of the two forms of activated carbon showed preferential accumulation of powdered activated carbon within the sand pack, which could result in sampling bias.

钻孔剪切力学参数表征修正方法及其实验研究

钻孔剪切法是现场快速实测岩石抗剪强度的重要方法,但因测量误差较大导致其应用受限。通过对钻孔剪切原理及研究成果分析,发现了不完全剪切是岩石钻孔剪切试验误差大的原因,提出了基于压、剪不等面积的钻孔剪切法修正方法。设计实验装置开展钻孔剪切模拟试验,研究了不同剪切板参数下砂岩剪切力学参数表征规律,证明了所提方法的有效性和修正效果,最后通过文献数据验证了该方法的适用性。具体结果如下:①岩石钻孔剪切试验误差大的根本原因是受压面积和剪切面积选取失真且不相等,实际剪切破坏面积小于剪切齿齿间面积,且不同剪切齿长度情况下修正受压面积和剪切面积均随法向力的增大线性增大。基于剪切齿参数、受压面积和剪切面积的关系式,提出了钻孔剪切法修正方法。②岩石钻孔剪切的剪应力−剪切位移曲线可分为压密阶段、似弹性变形阶段、塑性变形阶段和峰后阶段。随法向力增大,不同剪切板参数下正应力、剪应力和剪切刚度均增大,达到剪应力峰值时的位移减小。钻孔剪切参数与剪切力学参数表征值之间存在明显规律。随剪切齿齿长的增加,黏聚力线性增大,内摩擦角呈二次函数增大。随剪切板面积的增加,黏聚力线性增大,内摩擦角呈二次函数减小。③剪切齿齿长和剪切板面积增大可在一定程度上减少测量偏差。剪切齿齿长从1.0 mm增大到2.5 mm,黏聚力和内摩擦角测量值的总偏差从62.96%降低到19.91%,总修正提升值从30.8%提高到74.1%;剪切板面积从400 mm^(2)增大到520 mm^(2),黏聚力和内摩擦角测量值的总偏差从64.07%降低到37.69%,总修正提升值从39.56%提高到56.05%。实验和文献数据验证均表明,本修正方法可以使钻孔剪切法测得的黏聚力和内摩擦角准确度分别提升约50%和6%。

养殖池塘水体原位修复技术研究进展

我国作为全球水产养殖大国,养殖规模和产量均居世界首位。池塘养殖是我国最主要的水产养殖模式,在保障优质动物蛋白供给、促进农业增效和农民增收等方面发挥重要作用。随着养殖集约化水平不断提高,养殖密度持续增加,大量饲料投入和动物排泄等导致养殖池塘水体富营养化严重,大量氨氮和亚硝酸盐等不仅污染养殖水体,还会严重危害水产动物健康,导致病害频发、药物滥用、食品安全等一系列问题,给水产养殖绿色可持续发展带来严重挑战,亟需进行养殖池塘水体修复处理。目前,对养殖水体的修复技术主要分为原位修复和异位修复。相较于异位修复,原位修复技术具备节约资源、成本低、无交叉污染等优势,因此具有广阔的应用前景。基于此,该文首先概述了我国养殖池塘水体污染物的主要来源、特征和危害;其次,从物理、化学和生物处理技术3个方面总结了我国养殖池塘水体原位修复技术的研究进展,并详细阐述其技术原理、适用范围、应用效果及优缺点;最后,指出当前池塘养殖水体原位修复存在的主要问题,对未来的研究方向进行展望,并提出一种单塘循环生态养殖模式,为养殖池塘水体修复的未来研究和应用提供参考。

黑臭水体底泥处理技术发展现状

我国河湖黑臭水体问题极大地影响了生态环境系统,并对人体健康和经济发展构成威胁。目前随着我国大力推进黑臭水体治理,截污系统逐渐完善,底泥中污染物释放及在厌氧环境下发酵产生的嗅味物质引发的内源污染成为了河湖黑臭的重要原因。因此,黑臭水体底泥治理成为了水环境治理领域的热点和难点,目前针对黑臭水体底泥的主要处理方法有异位修复和原位修复两大类。本文针对黑臭水体底泥的成因、组成及危害做出分析,系统阐述了异位修复技术和原位修复技术的分类、原理及各处理技术的利弊,并对底泥修复技术的发展做出展望,明确了原位修复技术的巨大发展空间。

地下水污染修复技术及其国内工程应用进展

地下水污染具有长期性、隐蔽性、难恢复性等特点,开展地下水污染场地的修复工作是一项巨大的挑战。对此,国内外研究团队提出了多种修复技术,但如何选择适用于我国地下水污染场地的技术或技术组合,对我国地下水污染治理具有重要意义。本文对常用修复技术在我国的工程应用情况进行调查整合,并从技术原理、场地水文地质条件的适用范围及工程应用效果等方面对其进行具体探讨,综述了地下水污染场地修复技术筛选常用方法,希望为我国地下水污染场地修复提供些许参考。

细粒尾矿无土修复后土壤有机碳累积特性

铜等大宗尾矿无土化原位修复是尾矿资源化、无害化利用的有效途径。修复后土壤养分蓄积直接关系到后期田间管理,对其有机碳等重要养分积累规律研究至关重要。针对我国湖北某细粒铜尾矿修复场地进行研究,对未经修复、修复一年与修复两年的0~15、15~30、30~45 cm三种深度的土壤进行取样,对总有机碳、易氧化态有机碳、颗粒态有机碳、矿物结合态有机碳、可溶性有机碳与微生物量有机碳6种土壤有机碳形态进行测定并分析其变化规律。结果表明:经无土修复后的细粒尾矿土在无外源有机物的添加下依然会进行土壤总有机碳的积累;尾矿进行有机碳积累的主要方式是以矿物结合态有机碳为代表的惰性有机碳的增加,惰性碳的升高有助于固定有机碳;尾矿的团聚体粒径尺寸与土壤总有机碳的含量呈正相关,其中惰性有机碳更偏好聚集在粒径较小的团聚结构中,土壤碳库活性逐渐增强,更容易发生有机碳的转化;对尾矿土进行修复后土壤有机碳含量有显著提高,且主要以惰性有机碳的形式积累,在该场地表现出了巨大的碳汇潜力。该研究同时明确了该场地修复后矿区土壤有机碳各形态的累积特性,可为指导尾矿修复工作提供数据支持。

挥发酚污染场地地下水原位氧化修复半径确定的应用研究

为探究确定更加合理的原位化学氧化(ISCO)地下水修复半径,本文以北方某地下水挥发酚污染场地为研究对象,设计和建立了一套由1口注射井和6口地下水观测井组成的现场原位化学氧化修复试验系统,估算单井氧化药剂注入影响半径。结果表明:(1)通过不同方向地下水水位变化速率、不同特征因子检测浓度变化趋势相互校准验证分析,氧化药剂扩散呈现各向异性的结果。(2)注射井向四周扩散的速率不相同,沿地下水流向下游方向扩散速度最快,其次是药物注射井和已有污染监测井连线方向,上游扩散速度最慢。(3)单次连续注射药剂量2 m^(3)条件下,地下水下游方向(OA)的影响半径约为3.0 m,地下水垂直方向(OB和OD)的影响半径出现不同的形态,其中OB方向与地下水上游方向(O)一致,约为0.8 m,但OD方向影响半径约为1.5 m。研究显示,本次现场试验验证了氧化药剂的修复效果,确定了单井氧化药剂注入影响半径及其几何形态的技术效果,提高了影响半径的判定精度,可为相关污染场地地下水原位氧化修复半径的确定提供参考。

不同载体固定活性污泥原位修复轻度淤积底泥的效能

底泥修复是黑臭水体治理中的重要环节,原位修复操作简便且对河道的破坏小。利用固定化菌剂原位修复实验装置,探究了活性炭、沸石、陶粒3种载体固定活性污泥修复轻度淤积底泥的效能。载体物理特性及载体对微生物的吸附特性实验结果表明,活性炭相对于沸石和陶粒具有更丰富的孔隙结构和更强的活性污泥吸附能力,沸石的吸附能力强于陶粒。不同载体固定活性污泥原位修复轻度淤积底泥实验结果表明,3种载体固定活性污泥均能有效降低底泥中有机质含量,其中活性炭固定活性污泥对底泥中有机质的降解效果最佳,60 d内有机质含量可降低45.2%;3种载体固定活性污泥均能促进底泥中重金属离子转移,其中沸石固定活性污泥对重金属离子的去除效果最佳,60 d内对铜离子、铬离子、铅离子的去除率分别达到了28.8%、27.2%、37.2%;此外,3种载体固定活性污泥均能有效去除上覆水中的CODCr、NH3-N、TN、TP,60 d内CODCr去除率基本超过50%,NH3-N、TN、TP去除率基本超过80%。综合底泥和上覆水处理效果可知,活性炭固定活性污泥的表现最优,其次为沸石固定活性污泥。

原位优势菌人工浮岛耦合生态基处理炼化黑臭水体中试研究

纳污水体的整治成为炙手课题,但对东北高寒盐的纳污水体净化技术未完善。本研究以生态基为膜载体,利用其与芦苇人工浮岛、原位优势菌形成的耦合修复体系开展东北地区某炼化纳污水体净化效果研究。研究表明,当在温度25℃,溶氧浓度4 mg/L,pH值8.0,以碳素纤维草为材料作为生态基,投放密度2根/浮岛单元的环境下时,该耦合系统对纳污上覆水体COD、NH_(4)^(+)-N、TN和TP平均去除率为最佳,可达到78.40%、79.18%、84.05%和79.76%。实现了炼化纳污水体的原位净化目标,提升了上覆水污染物的去除率,为该技术在炼化纳污上覆水体原位治理工程化应用中系统构建与运行提供理论基础。

过碳酸钠-过硫酸钠双氧化体系降解地下水中三氯乙烯

为了解决单一氧化体系降解地下水中三氯乙烯的效率不高的问题,采用柠檬酸螯合Fe^(2+)催化过碳酸钠与过硫酸钠协同降解地下水中的三氯乙烯,考察过碳酸钠和过硫酸钠的配比、水质条件(pH、典型阴离子)以及三氯乙烯的初始浓度对三氯乙烯降解效率的影响。结果表明,当三氯乙烯的初始浓度为0.16 mmol/L时,在中性条件下,柠檬酸螯合Fe^(2+)催化过碳酸钠-过硫酸钠双氧化体系可以显著提高地下水中三氯乙烯的降解速率;三氯乙烯的降解受过碳酸钠与过硫酸钠的配比的影响,过碳酸钠、过硫酸钠、柠檬酸、 Fe^(2+)、三氯乙烯的物质的量比为10∶8∶5∶10∶1时,反应180 min后三氯乙烯的降解率为98.5%;随着反应体系pH增大,三氯乙烯的降解率逐渐降低;地下水中常见的阴离子SO_(4)^(2-)、 NO_(3)^(-)对该双氧化体系去除地下水中三氯乙烯的影响较小,但较高浓度的HCO_(3)^(-)、 Cl^(-)显著抑制三氯乙烯的降解;自由基清扫实验确定双氧化体系中存在氢氧自由基HO·、硫酸根自由基SO_(4)^(-)·、超氧自由基O_(2)^(-)·等自由基,且HO·对三氯乙烯的降解起主导作用。

活化过硫酸钠处理苯并[a]芘污染土壤的应用研究

为了研究异位化学氧化技术对苯并[a]芘污染土壤的修复效果,在实验室开展模拟化学氧化烧杯试验,对比测试了Fe^(2+)、生石灰及过氧化氢等药剂活化过硫酸钠的处理效果,试验结果发现生石灰活化表现出最好的修复效果,其次是亚铁盐活化。选用生石灰活化和硫酸亚铁活化的方式开展中试,结果表明生石灰活化的修复效果更优,并且确定过硫酸钠的投加量为土壤质量的1.0%。最后开展了约280 t污染土壤的工程应用,达到了修复目标。通过成本分析得知,生石灰活化的方式更经济。

原位吸附技术修复六价铬污染土壤

常见六价铬Cr(Ⅵ)污染场地修复技术如客土法、还原法、固化法、生物法等存在成本高、效率低及Cr(Ⅵ)被二次氧化等缺点。理想修复技术应能快速、低成本地将铬元素(Cr)从土壤中彻底去除。本文将聚吡咯(PPy)通过原位聚合的方式负载在凹凸棒土(ATP)表面,制备了以PPy为“壳”和以ATP为“核”的ATP/PPy复合材料,ATP/PPy对Cr(Ⅵ)的最大吸附容量为185.19mg/g,吸附机理包括静电引力、螯合、还原与离子交换等。将ATP/PPy嵌入土壤中,利用Cr(Ⅵ)在土壤中的纵向迁移及横向浓度差渗透,可实现对土壤中Cr(Ⅵ)的原位吸附。实验考察了模拟降雨量、土壤pH、土壤容重、土壤有机质含量等因素对土壤中Cr(Ⅵ)去除效率的影响。结果表明,当供试土壤中Cr(Ⅵ)浓度为30mg/kg,模拟降雨量为6mL/天,土壤有机质含量为7.6g/kg,土壤容重为1.22g/cm^(3),土壤p H为5.86时,第35天时土壤滤液中Cr(Ⅵ)去除率为58.51%,土壤中Cr(Ⅵ)含量降低至2.97mg/kg,低于《土壤环境质量建设用地土壤污染风险管控标准(试行)》(GB36600—2018)中的建设用地第二类用地筛选值5.7mg/kg。该技术具有操作简单、经济环保、效率高、去除彻底等优势,可为污染场地的高效低成本治理提供新思路及技术支撑。