受污染沉积物原位覆盖材料研究进展

原位覆盖技术是一种新兴的沉积物修复技术,它与传统的受控自然恢复技术和疏浚技术相比,具有较好的修复效果、更小的生态风险与更低廉的成本,引起了广泛的关注.在20世纪70年代后期,原位覆盖技术已经应用到受污染沉积物修复中.经过近30年的发展,原位覆盖技术已经在美国、德国、日本、澳大利亚、挪威与加拿大等国家的受污染现场应用中取得了成功,并且在工程实践和理论研究相互促进过程中,该技术得到进一步的完善.其中,原位覆盖材料表现得更为突出,使得原位覆盖技术的应用前景变得广阔.本文对近年来国际上原位覆盖工程实践中各种覆盖材料的应用状况和实际修复效果进行了总结,为其在我国的应用起到推动作用.     

原位生物技术对城市重污染河道底泥的治理效果

以扬州市典型城市内河河道为例研究了人工曝气、生态砖覆盖、生物填料覆盖、低位植物浮床(简称低位浮床)等原位生态处理技术对河道底泥污染释放及其对上覆水污染负荷贡献的治理效果.研究结果表明:经不同原位生态处理后,1)底泥中氨氮的释放速率下降50.3％-89.64％,平均为59.27％;底泥污染释放对上覆水氨氮负荷贡献量的去除率为36.59％-82.67％,平均为53.33％;2)底泥中总氮的释放速率下降20.96％-88.94％,平均为42.32％;底泥总氮释放对上覆水污染负荷贡献量的污染去除率为38.00％-67.06％,平均为54.96％;3)底泥中总磷的释放速率下降27.49％-91.00％,平均为55.31％;底泥总磷释放对上覆水总磷污染负荷贡献量的去除率为67.14％-98.46％,平均为84.33％;4)底泥中CODMn的释放速率下降11.84％-79.32％,平均为41.16％;底泥上覆水中CODMn的释放速率下降-1.25％--70.74％,平均为29.83％.研究还发现,原位生态处理技术在运行中对底泥污染治理的效果受该技术对底泥的扰动程度的影响,在进行集成应用的时候,对底泥扰动较大的技术应与对底泥扰动较小的技术相间应用,以减少工程技术运行中对底泥扰动造成的污染爆发式释放,达到更好的整体处理效果.     

持久性有毒物污染底泥修复技术进展

评述了底泥中持久性有毒污染物的危害。在分析持久性有毒污染物污染底泥修复技术现状及面临问题的基础上 ,指出浅水湖泊持久性有毒污染物污染底泥修复的发展方向是植物 -微生物联合修复 ,水库、深水湖泊等持久性有毒物污染底泥修复的发展趋势为物理化学 -生物协同修复 ,修复目标是在环保疏浚、生态清淤的基础上 ,实现持久性有毒污染物污染底泥的无害化和资源化处置     

城市河道底泥污染生物修复技术研究

城市河道受污染底泥对水体产生大的二次污染,为有效的控制底泥污染物的释放和开发有效的水体治理技术方法,本研究利用人工模拟河道在连续流条件下,对河道污染底泥的生物修复及其对水体生物修复的影响进行了试验研究。研究结果表明:采用曝气增氧和投加底泥生物修复制剂联合处理的方式能达到好的底泥生物修复效果,能有效的提高底泥的生物降解活性(G值),削减底泥氮磷污染物的释放量,底泥G值与底泥氮、磷污染物释放量呈显著负相关性:单独采用曝气增氧和投加土著微生物制剂联合实施的生物修复方法对河道污染水体均具有良好的修复效果,但底泥的生物修复将对河道水体生物修复的效果产生大的影响。底泥生物修复后,对水体进行生物修复的处理效果更加显著,在相同实验条件下,对水体COD、氨氮的最大去除率由65.0%和16.30%提高到72.0%和41.0%,水体生物修复的周期由13 d缩短为6 d。     

不同覆盖方式对底泥内源营养盐释放的控制效果

通过底泥内源营养盐释放控制室内模拟试验,考察了塑料包被、斜发沸石、方解石、石英砂和硝酸钙5种覆盖材料对底泥氮磷释放效率的影响,系统分析了各自优劣程度,为实际环境中不同污染背景水体选择适宜的控制技术提供科学依据.结果表明: 不同覆盖材料对底泥总磷释放的控制效果依次为:塑料包被>硝酸钙>斜发沸石>方解石>石英砂;不同覆盖材料对底泥总氮释放的控制效果依次为:斜发沸石>塑料包被>方解石>石英砂>硝酸钙;不同覆盖材料对底泥硝态氮释放的控制效果依次为:塑料包被>斜发沸石>方解石>石英砂>硝酸钙;不同覆盖材料对底泥铵态氮释放的控制效果依次为:硝酸钙>石英砂>斜发沸石>方解石>塑料包被;温度和底泥内源营养盐释放有对应关系,水样中总磷、总氮和硝态氮浓度会随着温度上升而增加,而铵态氮浓度呈下降趋势.     

持久性有机污染土壤的植物修复及其机理研究进展

随着人类对化学品的依赖程度越来越高,环境的有机污染状况也越来越严重.有机污染土壤的植物修复是指利用植物在生长过程中,吸收、降解、钝化有机污染物的一种原位处理污染土壤的方法,具有应用成本低、生态风险小、对环境副作用小等特点.本文综述了近年来国内外有机污染土壤的植物修复研究进展情况,重点介绍了多氯联苯、多环芳烃、农药和硝基芳香化合物等持久性有机污染物的植物修复,阐述了有机污染土壤植物修复的关键机制,并分析了该技术在实际工程应用中的局限性及应考虑的因素.最后,指出了今后该领域的重点研究方向.     

铁基生物炭联合生物电化学原位修复Pb-多环芳烃复合污染底泥的效果与机理

城市河道及附近水体底泥是重金属和持久性有机污染物的重要汇集地。本研究以Pb-菲复合污染底泥为对象,探索铁基生物炭联合微生物电化学技术对底泥的原位修复效果与机理。结果表明,通过浸渍烘干法制备的铁基生物炭表面铁以Fe₃O₄和γ-Fe₂O₃为主,具有磁性。铁基生物炭联合生物电化学(0.2 V)使底泥中菲的去除速率提高6.75倍,主要原因在于阳极可作为电子受体强化底泥中菲的共代谢降解,额外投加葡萄糖加速了底泥菲的生物电化学降解,导致菲的去除速率增大1.09倍。同时,阳极生物电化学过程降低了底泥pH,促进了底泥Pb向弱酸可溶态转化,在电场力作用下向阴极迁移并转化为残渣态。高通量测序结果表明,铁基生物炭联合生物电化学促进了底泥中Tissierella、Erysipelotrichaceae和Pseudomonas三类细菌的生长,导致了菲的生物电化学强化降解及Pb活化。     

环境因子对厌氧微生物脱卤的影响研究进展

有机卤代物在工农业生产中的广泛应用及不合理处置与排放导致其成为地下环境中普遍存在的一类污染物,严重威胁地下生态系统功能、饮用水安全和人类健康。有机卤呼吸细菌在有机卤污染场地的原位生物修复中起到了至关重要的作用。本文简要概述了影响和制约有机卤呼吸微生物生长代谢及脱卤活性的一些关键环境因子,如pH、温度、盐度、电子供受体和氧气等,并且对有机卤呼吸细菌未来的研究方向提出展望,以期为污染场地原位生物修复工程的有效实施提供理论与技术参考。     

治理室内甲醛污染技术的研究进展

甲醛是室内空气中的主要污染物之一。本文论述了近年来国内外对甲醛污染治理的几种方法,分析了各类方法的技术原理、及优缺点。     

广州市河涌水环境原位治理生物修复技术

针对广州市河涌治理的紧迫性、复杂性以及传统治理方法的缺陷与不足,本文介绍了一种利用生物修复技术原位治理广州黑臭河涌污染的方法。该方法通过河道曝气增氧、投放微生物菌剂、底泥生物修复和设置生物巢系统等步骤和措施,控制和消除河涌外源和内源污染,净化河涌水质,提高水体自净能力,达到消除黑臭、消除河道底泥的目的。本方法无须在河道中兴建构筑物,也无须清疏河道底泥,普遍适用于截污、清淤的河涌,以及受潮汐影响流态变化复杂的河道进行原位治理,恢复水体正常生态功能,为众多的城镇黑臭河涌提供了切实可行、经济方便的治理方法。     

Genomic tools in bioremediation

Bioremediation is a process that uses microorganisms or their enzymes to remove pollutants from the environment. Generally, bioremediation technologies can be classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site while ex situ involves the removal of the contaminated material to be treated elsewhere. Like so much else in biology, the ease and availability of genomic data has created a new level of understanding this system. Bioremediation capabilities of the microbial population can be analyzed; not only by physiological parameters, but also by the use of genomic tools, and efficient remediation strategies can be planned. PCR and DNA- or oligonucleotide-based microarray technology is a powerful functional genomics tool that allows researchers to view the physiology of a living cell from a comprehensive and dynamic molecular perspective. This paper explores the use of such tools in bioremediation process.     

Comparison of the Long-Term Risks of Removal and In Situ Management of Contaminated Sediments in the Fox River

The long-term potential risks of environmental dredging vs. in situ contaminated sediment management practices are discussed and compared for the Lower Fox River, Wisconsin. The risks are identified as being largely associated with the residual sediment contamination associated with either approach. The integral of the surface area-weighted average contaminant concentration in surface sediment is proposed as a metric to compare these risks. Capping is shown to exhibit significantly reduced exposure and risk relative to the dredging scenarios, even if potential undetected erosion of 5% of the cap is considered. Even with the improbable event of undetected failure of 25% of the cap, the exposure and risk associated with capping is approximately equal to or below all dredging scenarios. A preference for dredging due to the perception that it eliminates the long-term risk of in situ capping is not supported by this analysis. Although strictly applicable only to the Lower Fox River, the results suggest sitespecific analyses must be conducted to determine which sediment management approaches minimize the potential for long-term exposure and risk.     

Screening Software for an Innovative In Situ Bioremediation Technology

Innovative in situ treatment technologies show promise as efficient methods for remediating the nation's waste sites. Unfortunately, due to various barriers, some innovative technologies that have been demonstrated at full scale are never transferred for commercial application. The National Research Council (NRC) has recently presented recommendations on how to overcome these barriers (NRC, 1997). User-friendly screening software, which specifically addresses each of the NRC recommendations, is presented for use by site managers to determine the appropriateness of an innovative remediation technology, in situ aerobic cometabolic bioremediation, to clean up a contaminated site with specified hydrogeologic and contaminant characteristics. The software estimates the performance and cost of the technology at the site. Software, such as the one presented, can be used to aid in the transfer and implementation of innovative remediation technologies.     

Effects of a modified zeolite on P and N processes and fluxes across the lake sediment–water interface using core incubations

A new locally produced P-inactivation agent, Z2G1, was tested on sediment cores from Lake Okaro, New Zealand, for phosphorus (P) removal efficacy and any non-target side effects prior to a whole lake trial to manage internal P loading. Z2G1 is a granular product which settles rapidly, and was designed as a sediment capping material. It is a modified zeolite which acts as a carrier for the aluminium (Al)-based P-binding agent. It was found to have a high affinity for P and did not release Al into the water column. Continuous-flow incubation study results showed that a thin layer of Z2G1 (~2 mm) could completely block the release of P from the sediment under aerobic and anoxic conditions, and remove P from the overlying water in contact with the capping layer. The Z2G1 capping layer neither released metals itself nor did it induce the release of metals from the sediments, and the zeolite substrate absorbed arsenic and mercury from the geothermally influenced Lake Okaro sediments. In general, zeolites are strong cation absorbers and the zeolite substrate of Z2G1 absorbed ammoniacal nitrogen, making it the only sediment capping material to actively remove both P and N. There were, however, indications of a suppression effect on microbial denitrification by the Z2G1 capping layer under aerobic conditions. Overall, the Z2G1 sediment capping material is a highly effective P-inactivation agent which might be a useful material for managing internal P loads in eutrophic lakes.     

重金属污染土壤中生物间相互作用及其协同修复应用

土壤是人类赖以生存的物质基础。我国土壤重金属污染状况不容乐观,给人类健康构成严重威胁。生物修复重金属污染土壤被广泛认为是可持续的修复技术,但当前仍存在修复效率不高的科学瓶颈问题。土壤中生活着丰富的微生物、植物和动物,且这些生物之间存在着复杂的相互作用,并且通过物质循环和能量传递形成了错综复杂的食物网联系。土壤生物间的相互作用能深刻影响土壤中污染物的迁移转化和生物修复的效率,多元生物协同的修复技术集合了单一生物修复方法的优势,具有强化生物修复效果的巨大潜力。文中综述了土壤中微生物-植物-动物之间的相互作用,及其对土壤重金属迁移转化和生物修复效果的影响,并对定向调控土壤食物网结构、提高重金属污染土壤的生物修复效果、建立基于食物网的多元生物协同修复技术进行了展望。     

Assessment of the ecological status of regulated lakes: stressor-specific metrics from littoral fish assemblages

Although in situ sediment capping is frequently used to reduce internal loading of contaminants and nutrients, post-application assessment rarely includes the potential undesirable short-term effects on plankton species composition. We hypothesised that a modified zeolite (Z2G1) application as a sediment capping agent in Lake Okaro, New Zealand, could cause significant undesirable shifts in species composition of both zooplankton and phytoplankton due to burial of resting stages or interference with feeding for the zooplankton. Alternatively, we predicted that the capping agent might have no effect due to, for example, the coarse grain size of the material (1–3 mm). We used multidimensional scaling (MDS) and analysis of similarity (ANOSIM) to identify any adverse effects of Z2G1 on zooplankton and phytoplankton species composition (i.e. shifts in community structure, including species loss) by comparing the community structure before and after the Z2G1 application. We found no significant differences in species composition before and after the Z2G1 application at the depths investigated (surface and 9 m). However, all of the analyses showed statistically significant differences among seasons, indicating seasonal variations in plankton composition far outweigh those that may have resulted from the Z2G1 application. Coarse particle size, low dose rate and a restricted area where the sediment capping agent was applied were considered to be the factors limiting potential adverse effects on plankton species. Considerations of finer-grained material to increase coverage and efficacy of phosphorus adsorption require assessment for their effects on zooplankton, however, and a direct mode of application into the hypolimnion is recommended to minimise effects on zooplankton and phytoplankton communities.     

建立污染土壤修复标准的探讨

随着污染土壤修复技术的发展和污染土壤修复环境工程的实施,污染土壤修复标准的建立已成为检验污染土壤修复工程效果的瓶颈.我国现行的土壤环境质量标准已不能适应污染土壤修复效果评判的需要.本文在分析我国土壤环境质量标准不足的基础上,结合一些发达国家土壤修复标准以及我国土壤污染实际情况,提出建立污染土壤修复标准应从污染物的选择、分析检测方法、修复标准的分类、对地下水的保护和生态毒理学评价方面综合考虑.     

微生物厌氧呼吸与有机污染水体沉积物修复

水体沉积物有机污染是当前全球关注的重要环境问题。微生物具有呼吸和代谢多样性,能以多种污染物作为厌氧呼吸的电子供体或受体,与周围环境中的生物和非生物因素组成代谢网络耦合有机污染物降解转化,是有机污染水体沉积物修复的重要驱动者。本文重点综述了微生物厌氧呼吸、电子传递网络及其对有机污染水体沉积物的修复机制研究进展,并对有机污染水体沉积物微生物修复理论和技术研究的问题和挑战进行了探讨。     

Electrochemical Stimulation of PAH Biodegradation in Sediment

Natural attenuation of PAH in sediments is usually slow due to prevailing anaerobic conditions in sediments. Electrochemical stimulation of PAH biodegradation is proposed and demonstrated for remediation of contaminated sediment. Two graphite electrodes were placed horizontally at different depths in PAH-spiked sediments; the cathode was near the water-sediment interface and the anode was laid in the deeper sediment. An external power of 2 V was continuously applied to the electrodes to stimulate PAH biodegradation. Redox potential around the anode in powered reactors increased gradually, and was 50–150 mV higher than that in the control. pH around the anode decreased to ～6 from an initial value of 6.4 or 6.7 in powered reactors, which reflected water electrolysis. Phenanthrene concentration at the anode decreased with time, showing a unique Z-shaped profile in the sediment in powered reactors. PAH degrading genes around the anode in powered reactor were found to increase compared to the control reactor, which provided microbial evidence of biodegradation. These findings demonstrated the capability of this novel bioelectrochemical technology for the remediation of PAH-contaminated sediment.     

TOPSIS-Based Screening Method of Soil Remediation Technology for Contaminated Sites and its Application

A soil remediation technology screening system has not yet been established in China, and the existing supporting conditions for soil remediation technology cannot meet the supervision needs of contaminated sites’ remediation. Considering the soil remediation technology screening methods for contaminated sites in developed countries and the supervision requirements of contaminated sites in China, this article briefly introduces the main characteristics of decision-making methods, and the screening indices, including technical, economic, social, and environmental factors, are suggested. The technique for order performance by similarity to ideal solution (TOPSIS) was used to establish a screening process for soil remediation technology, and the analytic hierarchy process (AHP) method was utilized to obtain the weights of the screening indices. Tthe suggested screening method was then applied in a chromite ore-processing residue site in China, and suitable remediation technology (in-situ chemical reduction-oxidation) was proposed. The research results could provide scientific and technological support for the supervision of contaminated sites in China.