Remediation of in-situ Leach Mining Contaminated Soil by Amendment-plant Synergism

This study aimed to remediate in-situ leach mining contaminated soil by amendment-plant synergism. The results showed that plant species exhibited ex-tremely significant effects on the concentration of nitrate nitrogen; to be specific, the concentration of nitrate nitrogen in soil planted with wheat was reduced from 692.19 mg/kg to lower than 100 mg/kg; when the mass ratio of amendment to soil reached 3：50 and the amendment particle size was 1-2 mm, the concentration of nitrate ni-trogen in soil planted with wheat was reduced to 43 mg/kg. The amendment type exhibited extremely significant effects on the concentration of ammonium nitrogen; to be specific, when the mass ratio of amendment to soil reached 10：50, the concen-tration of ammonium nitrogen in soil added with 2-3 mm zeolite was reduced from 23 593.75 to 3 300 mg/kg on day 15. Amendments and plants mainly exhibited desorption performance for sulfate radical in soil, and the amendment type extreme-ly significantly affected the concentration of sulfate radical; to be specific, the con-centration of sulfate radical in soil added with limestone increased from 370 mg/kg to 900 mg/kg on day 7.

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.

Mathematical Modei of In-situ Ozonation for the Remediation of 2-Chlorophenol Contaminated Soil

A microscopic diffusion-reaction modei was developed to simulate in-situ ozonation for the remediation of contaminated soil, i.e., to predict the temporal and spatial distribution of target contaminant in the subsurface. The sequential strategy was employed to obtain the numerical solution of the modei using finite difference method. A non-uniform grid of discretization points was emploved to increase the accuracy of the numerical solution by means of coordinate transformation. One-dimensional column tests were conducted to verify the modei. The column was packed with simulated soils that were spiked with 2-chlorophenol. Ozone gas passed through the column at a flow rate of 100ml·min-1. The residual 2-chlorophenol content at different depths of the column was determined at fixed time intervals. Compared the experimental data with the simulated values, it was found that the mathematical modei fitted data well during most time of the experiment.

In-situ remediation of deep petroleum-contaminated soil injection

A computational fluid dynamics(CFD)numerical simulation and field experiment were used to investigate optimal operating parameters of high-pressure jet grouting equipment and clarify the boundary law of the injection area in the remediation process.The response surface optimization design results show that the optimal injection pressure is 30 MPa,rotation speed is 23 r/min,commission speed is 30 cm/min,and the optimal injection diameter is 147.3 cm.Based on the CFD numerical simulation,the ratio of the injection core,turbulent zone,and seepage zone is approximately 1∶4∶2.The distribution law of jet core,turbulence zone and seepage zone at different cross-sections under 30 MPa operating conditions is as follows:The jet core radius is approximately 100 mm,the turbulence zone is mainly distributed at 100 to 500 mm,the seepage zone is mainly distributed at 500 to 700 mm,the seepage zone could be completed within 2 h,and the proportion of the three boundary zones in the injection zone is similar to that of the numerical simulation.This study provides theoretical parameters and practical reference for the remediation of deep pollution via in-situ chemical oxidation in the Loess Plateau soil environment.

Measures for controlling large deformations of underground caverns under high in-situ stress condition--A case study of JinpingⅠhydropower station

The Jinping I hydropower station is a huge water conservancy project consisting of the highest concrete arch dam to date in the world and a highly complex and large underground powerhouse cavern. It is located on the right bank with extremely high in-situ stress and a few discontinuities observed in surrounding rock masses. The problems of rock mass deformation and failure result in considerable challenges related to project design and construction and have raised a wide range of concerns in the fields of rock mechanics and engineering. During the excavation of underground caverns, high in-situ stress and relatively low rock mass strength in combination with large excavation dimensions lead to large deformation of the surrounding rock mass and support. Existing experiences in excavation and support cannot deal with the large deformation of rock mass effectively, and further studies are needed. In this paper, the geological conditions, layout of caverns, and design of excavation and support are first introduced, and then detailed analyses of deformation and failure characteristics of rocks are presented. Based on this, the mechanisms of deformation and failure are discussed, and the support adjustments for controlling rock large deformation and subsequent excavation procedures are proposed. Finally, the effectiveness of support and excavation adjustments to maintain the stability of the rock mass is verified. The measures for controlling the large deformation of surrounding rocks enrich the practical experiences related to the design and construction of large underground openings, and the construction of caverns in the Jinping I hydropower station provides a good case study of large-scale excavation in highly stressed ground with complex geological structures, as well as a reference case for research on rock mechanics.

Connotation and strategic role of in-situ conversion processing of shale oil underground in the onshore China

In-situ conversion processing (ICP) of shale oil underground at the depth ranging from 300 m to 3 000 m is a physical and chemical process caused by using horizontal drilling and electric heating technology, which converts heavy oil, bitumen and various organic matter into light oil and gas in a large scale, which can be called"underground refinery". ICP has several advantages as in CO2capture, recoverable resource potential and the quality of hydrocarbon output. Based on the geothermal evolution mechanism of organic materials established by Tissot et al., this study reveals that in the nonmarine organic-rich shale sequence, the amount of liquid hydrocarbon maintaining in the shale is as high as 25%in the liquid hydrocarbon window stage (R o less than 1.0%), and the unconverted organic materials (low mature-immature organic materials) in the shale interval can reach 40%to 100%. The conditions of organic-rich shale suitable for underground in-situ conversion of shale oil should be satisfied in the following aspects, TOC higher than 6%, R o ranging between 0.5%and 1%, concentrated thickness of organic-rich shale greater than 15 meters, burial depth less than 3 000 m, covering area bigger than 50 km2, good sealing condition in both up-and down-contacting sequences and water content smaller than 5%, etc. The shale oil resource in China’s onshore region is huge. It is estimated with this paper that the technical recoverable resource reaches 70-90 billion tons of oil and 60-65 trillion cubic meters of gas. The ICP of shale oil underground is believed to be a fairway to find big oil in the source kitchen in the near future. And it is also believed to be a milestone to keep China long-term stability of oil and gas sufficient supply by putting ICP of shale oil underground into real practice in the future.

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.

Development of a pressure coring system for the investigation of deep underground exploration

To provide a more accurate evaluation of the scale of deep underground resources,a new pressure coring system was carefully developed and its strength and safety of the engineering were verified by theoretical analyses and numerical simulation.The designed pressure coring system can obtain cores with length of 3 m and diameter of 50 mm at 70 MPa.The results of the ball-drop operation experiment demonstrate that differential motion assembly can effectively cut a safety pin by applying a tensile force of 4852 N,and it can lift the core tube through the center pole to complete a series of mechanical actions to seal the pressure.Additionally,by maintaining pressures at 70 MPa for 30 min,the pressure sealing capacity of the system was proven.Furthermore,a core sample with a diameter of 50 mm was obtained through a core drilling experiment and the coring performance of the pressure coring system was verified.This study can not only enrich the existing onshore coring technology but also provide a theoretical guide and design criteria for the development of similar pressure coring systems to meet the demand for deeper underground exploration.

Research progress and mechanism of nanomaterials-mediated in-situ remediation of cadmium-contaminated soil:A critical review

Cadmium contamination of soil is a global issue and in-situ remediation technology as a promising mitigation strategy has attracted more and more attention.Many nanomaterials have been applied for the in-situ remediation of cadmium-contaminated soil due to their excellent properties of the nano-scale size effect.In this work,recent research progress of various nanomaterials,including carbon nanomaterials,metal-based nanomaterials and nano mineral materials,in the removal of cadmium and in-situ remediation of cadmiumcontaminated soil were systematically discussed.Additional emphases were particularly laid on both laboratory and field restoration effects.Moreover,the factors which can affect the stability of cadmium,main interaction mechanisms between nanomaterials and cadmium in the soil,and potential future research direction were also provided.Therefore,it is believed that this work will ultimately contribute to the myriad of environmental cleanup advances,and further improve human health and sustainable development.

改性羟基磷灰石负载零价铁去除模拟地下水中Cr(Ⅵ)的研究

为了有效去除模拟地下水中Cr(Ⅵ),采用化学还原法将零价铁负载在腐植酸改性后的羟基磷灰石上制成复合材料。研究了改性羟基磷灰石负载零价铁材料对模拟地下水中Cr(Ⅵ)的去除效果,探讨了复合材料投加量、初始pH值、Cr(Ⅵ)初始浓度以及共存阴离子对降解效果的影响。结果表明,在相同条件下改性羟基磷灰石负载零价铁对Cr(Ⅵ)具有良好的去除效果;初始pH值和Cr(Ⅵ)初始浓度越低,去除率和去除速率均越高;当Cr(Ⅵ)初始质量浓度为1 mg/L,复合材料投加量为0.1 g/L时,反应120 min后,Cr(Ⅵ)质量浓度低于0.004 mg/L;共存阴离子PO_(4)^(3-)、CO_(3)^(2-)对复合材料的抑制作用比较明显。

铬污染地下水治理现状

地下水铬污染问题日益突出物理、化学和生物修复技术处理铬污染地下水都具有应用潜力。本文概述了地下水铬污染的来源和潜在影响,并论述了吸附、氧化、还原、离子交换、生物修复等修复技术处理铬污染地下水的机制。提出当前修复铬污染地下水问题需要跨学科的综合方法和创新技术来解决,以现有认知可以证实上述修复技术去除六价铬(Cr(Ⅵ))和三价铬(Cr(Ⅲ))核心技术的应用潜力。此外,也提出了限制各种修复技术发展的瓶颈在于修复成本高和长期稳定性差等,在今后的研究中有必要给予足够的关注,以推动多种修复技术走向应用。

污染地下水原位治理技术——透水性反应墙法

20世纪90年代初期在美国和加拿大兴起的原位被动修复技术———透水性反应墙,是一种地下水污染原位处理方法。其通过在垂直于地下水流动方向设置活性渗滤墙,当地下水流通过活性渗滤墙时,污染物与墙体材料发生化学反应,从而达到环境修复的目的。该技术具有原理简单,施工方便,能持续原位处理,处理组分多,且运行费用低廉等特点,能有效吸附和降解多种重金属和有机污染物。该方法目前在欧美已开始进入广泛的工程应用阶段,正逐步取代运行成本昂贵的抽水处理技术,成为地下水修复技术的发展方向。系统介绍了透水性反应墙法,阐述了反应墙的类型、活性材料的选取、反应机理、反应墙的构建以及应用实例,同时分析了其存在问题并展望其今后的研究方向。

内电解技术处理有机废水的应用进展

概括了近年来国内外采用内电解法处理有机废水的技术进展,总结了内电解技术在工程应用中存在的问题(如絮凝床堵塞、铁屑结块、填料床沟流、铁的钝化、生长生物膜、填料的更换等)及解决措施,并初步探讨了今后的工程应用和发展方向。

地下咸水体抽水修复的模拟试验

根据青岛市大沽河下游咸水分布区水文地质条件,采集该地区代表性中砂进行砂槽模拟试验,分析了抽水量、抽水井的位置以及抽水持续时间对咸水体修复效果的影响。试验结果表明:进行抽水修复时,各观测点盐度依次降低,并且形成突降;抽水量越大,咸水的去除速率越高,修复时间越短,抽水量从80.2 mL/min分别增至160.2 mL/min、240.2 mL/min时,修复时间缩短为之前的52.4%和34.9%;将抽水井安置在隔水边界附近,能够有效地抽取高浓度咸水,显著提高地下咸水体的整体修复效果;该试验条件下,抽水持续时间为115 min时,虽然结束抽水时的出水盐度为0.274%,但是依靠自然修复仍然能够满足饮用水标准,相较于出水盐度为0.10%的抽水持续时间缩短了30.3%,大幅降低修复成本,对咸水体的工程研究具有明显的经济意义。

污染地下水原位处理方法:可渗透反应墙

可渗透反应墙法是 2 0世纪 90年代新兴的一种地下水污染原位处理方法 ,该方法目前在欧美已开始进入广泛的工程应用阶段。该方法与早期的一些处理方法相比 ,具有能持续原位处理、处理组分多、价格相对便宜等特点。本文系统介绍了该处理方法的基本原理、系统的结构构造和类型、处理机理和反应材料以及设计与施工等 ,为在我国开展该方法的研究和应用打下基础。

膨润土在环境污染治理方面的研究进展

综述了国内外有关膨润土在环境污染治理方面的研究进展。膨润土及其改性产物 (活化膨润土、有机膨润土、交联膨润土、有机交联膨润土 )由于具有良好的吸附性能 ,在环境污染治理方面得到了越来越广泛的应用。在对含有机污染物、重金属的废水处理中 ,膨润土是一种高效吸附剂。欧美国家在土壤和地下水污染的防止和修复方面取得了较大的进展。近年来 ,有关膨润土用于放射性废物处置的理论研究活跃。

铅锌尾矿重金属渗漏污染土壤和地下水的电动修复技术研究

随着生产的发展,中国地下水重金属污染问题日益严重,特别是尾矿重金属渗漏污染地下水尤引人注目,地下水和土壤相互作用,导致重金属离子发生迁移和再分配。电动修复技术作为一种新兴绿色技术,因其高效、节能、成本低、无二次污染,具有很好发展前景。本文对土壤和地下水重金属污染电动修复技术的原理、实际研究应用、技术优势及缺点进行论述,为进一步研究铅锌尾矿重金属渗漏污染地下水电动修复技术提供理论依据。

基于“三源模式”的岩溶地下河区污染场地修复治理——以遵义坪桥地下河系统为例

在分析岩溶地下河系统范围内水源、污染源特性的基础上,建立了双源调查、源汇追踪和源头阻控为主要内容的岩溶地下河污染修复治理模式——三源模式。以遵义市坪桥地下河系统为例,利用三源模式对该地下河污染进行修复治理实践。结果表明:研究区分布有各类水点25处,以钻孔、岩溶泉点、地下河出口为主,特征污染物为以NH_(4)^(+)、NO_(3)^(-)、SO_(4)^(2-)、Mn^(2+)、Se^(2+)为主;分布有各类污染源点15处,以工业废渣堆放场为主,主要分布在地下河系统下游坪桥工业园区一带,特征污染物同样为以NH_(4)^(+)、NO_(3)^(-)、SO_(4)^(2-)、Mn^(2+)、Se^(2+)为主;地下河系统范围内有3条地下水污染通道,均分布在地下河出口与坪桥工业园区Z1(1^(#)、2^(#))废渣处置场之间;通过对2^(#)废渣处置场排洪竖井-地下河出口这一污染通道上游段进行帷幕工程修复后,地下河出口可减排污水排放量47244 m^(3)·a^(−1),NH_(4)^(+)、Mn^(2+)浓度可降低66%~78%,其中NH_(4)^(+)最低削减量为16250 kg·a^(−1),Mn^(2+)最低削减量为10960 kg·a^(−1)。研究结果可为类似地区岩溶地下河系统污染修复治理提供参考。

修复渗滤液污染物的新型PRB模型构建及可行性分析

针对垃圾填埋场渗滤液渗漏造成土壤及地下水等环境污染及其修复技术等问题,提出由环境友好型材料雾化钢渣(PS球)和废旧轮胎橡胶构建双层生物可渗透活性反应墙系统(DBPRBs),通过可行性分析表明该系统具有生物-非生物强化协同去污能力,该新型系统的构建和研究成果将进一步揭示污染地下水的PRB修复机理,对我国地下水污染的PRB修复产业发展具有重要的理论意义和实用价值。

煤炭地下气化废水的微生物修复研究

煤炭地下气化产生的废水污染直接限制了该技术的推广应用,针对此问题,采用筛选到的降解苯酚菌JP和降解萘菌KN,对模拟煤炭地下气化产生的废水进行降解修复试验。结果表明:经过72 h培养,煤炭地下气化废水的TOC下降80%以上,有机污染物种类减少近50%,酚类、杂环化合物、多环芳烃为代表的有机污染物种类和质量浓度减幅明显;重金属离子质量浓度均有所降低,Pb,Cd,Cu质量浓度降幅较大,最高可达100%;降解菌能在煤炭地下气化废水中存活,并能有效去除有机污染物和重金属离子。降解机理研究表明,JP菌降解煤炭地下气化废水中的吲哚时与喹啉和酚类物质存在共代谢,其对喹啉的降解遵循吡啶环开环途径;KN菌对喹啉的降解同时存在苯环开环与吡啶环开环2种途径,对多环芳烃的降解遵循水杨酸途径;两菌混合在对中间产物和终产物的利用上存在协同机制,有利于有机污染物的彻底清除。