A simple and convenient empirical survey method with a soil electrical conductivity meter for incineration residue-derived soil contamination

To facilitate field surveys for identifying areas of incineration residue-derived soil contamination, a simple and convenient method with a soil electrical conductivity meter was examined. First, the leaching test specified by Notification No. 13 of the Ministry of the Environment, 1973, was conducted on 506 samples of 11 types of wastes and compost, and the relationship between the concentrations of toxic elements [total Hg (T-Hg), Cd, Pb, Cr⁶⁺, and As] and values of electrical conductivity (EC) was examined. The results showed that bottom ash and fly ash were wastes with high EC values and that these wastes indicated higher levels of toxic elements. Second, an estimation method for the soil EC value of contaminated soil (ECc) was proposed based on the EC values of noncontaminated soil, and its usefulness was examined. The results of field surveys conducted at sites whose soils were suspected of contamination by dioxins and other pollutants derived from incineration residues showed that the contaminated spots and areas were identified by using ECc values. Moreover, comparison of the elemental contents of soils in terms of Cr, Ni, Zn, Na, K, Ca, Fe, Mn, and others, in addition to the above-mentioned toxic elements (excluding Cr⁶⁺), with those of the potential sources of pollution was verified to be effective for identifying the source of soil contamination.     

Contributions of common sources of polycyclic aromatic hydrocarbons to soil contamination

Asphalt products, particularly sealants, are prepared using petroleum products that contain a com‐plex mixture of aliphatic and aromatic hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs). Clearly, these products are ubiquitous in urban environments, which raises an issue regard‐ing the potential for PAHs to be transported from parking lots to underlying or adjacent soil, surface‐water bodies, or groundwater. Based on a literature review, there are limited studies focus‐ing on this issue; however, the studies that have been published have fascinating conclusions. The literature shows, as expected, that asphalt‐based products contain PAHs. The highest PAH concen‐trations are present in asphalt sealants, particularly those manufactured using coal tar. Furthermore, due to the low solubility and high partition coefficients of PAHs, the potential for PAHs to leach from asphalt surfaces is negligible, which has been confirmed by leachability studies. Thus, there is little risk that PAHs will be present in stormwater runoff or leach into groundwater from asphalt‐paved areas in a dissolved form. However, asphalt pavement and sealants produce particulate matter that can contain concentrations of PAHs in the sub‐percent range (100s to 1,000s mg/kg total PAHs) that is transported in stormwater runoff. Some studies show that this can cause soil and sediment con‐tamination with total PAH concentrations in the range of 1 to 10 mg/kg. From a remediation per‐spective, many site cleanups are conducted to remediate the presence of PAHs to cleanup goals below 1 mg/kg or, in some cases, 0.1 mg/kg or lower. From a total risk perspective, remediating sites to low PAH cleanup goals may be unwarranted in light of the risk of transportable PAHs produced from paved parking surfaces. In other words, is it reasonable to conduct a cleanup to remediate low PAH concentrations and then redevelop the area with asphalt pavement and sealant, which may pose a greater PAH‐related risk? © 2006 Wiley Periodicals, Inc.     

Application of fuzzy logic and sensitivity analysis for soil contamination hazard classification

The present article is aimed at illustrating a methodology for a rapid and effective assessment of pollution hazard connected with the presence of uncontrolled landfills. In particular, by means of a fuzzy approach, the criterion adopted allowed a comparison of the results obtained from a cross analysis of some intrinsic characteristics of the single landfills and the territory where they are located. Their identification shows the most relevant environmental problem. Therefore, we have classified each site within a hazard scale enabling us to understand which one requires to be checked more urgently, to do instrumental surveys and, if needed, to do restoration and reclamation. Moreover, the sensitivity analysis we carried out allowed us to identify which is the best membership function belonging and which is the best defuzzification method. That is, in particular, the trapezoidal function and the centroid method. The proposed fuzzy approach, supported by the sensitivity analysis, has revealed to be an important tool for supporting decisions, in order to optimise technical and economic resources.     

Fenton's in-situ reagent chemical oxidation of hydrocarbon contamination in soil and groundwater

Industry and regulatory demands for rapid and cost-effective clean up of hydrocarbon and other contamination in soil and groundwater has prompted development and improvement of in-situ remediation technologies. In-situ technologies offer many advantages over ex-situ treatment alternatives, including lower initial capital and long-term operation and maintenance costs, less site disruption, no Resource Conservation and Recovery Act (RCRA) liability, and shorter treatment time necessary to achieve cleanup objectives. Fenton's reagent, a mixture of hydrogen peroxide and ferrous iron that generates a hydroxyl free radical as an oxidizing agent, is widely accepted for chemical oxidation of organic contaminants in the wastewater industry. In-situ implementation of Fenton's reagent for chemical oxidation of organic contaminants in soil and groundwater continues to grow in acceptance and application to a wide variety of environmental contaminants and hydrogeologic conditions (EPA, 1998).     

安庆石化热电厂正压浓相气力输灰系统

详细介绍了安庆石化热电厂正压浓相气力输灰系统的组成、特点及运行情况。该系统自投运以来，运行情况良好。     

徐州电厂正压浓相气力输灰系统

详细介绍了徐州发电厂5号炉正压浓相气力输灰系统的结构及其特点。自该系统投运以来，运行情况良好。各项技术经济指标均达到了设计要求。     

石油开采行业土壤污染防治对策与建议

在文献和实地调研的基础上,分析了石油开采行业生产工艺及产排污情况,识别了油井、注水井、输油管道、联合站等主要工艺节点的土壤污染风险,总结了目前行业处理废水和危险废物的主要方法,指出了行业在废弃钻井液处理、地下输油管道泄漏后期处置及突发环境事件应急预案中土壤污染防治等方面存在的问题,并提出了相应的对策和建议。     

Remediation of groundwater contamination through conjunctive use of landfill gas management and soil vapor extraction

The recently completed performance testing of a conjunctive-use operation has demonstrated the applicability of combined landfill gas and Volatile Organic Compound (VOC) removal with overall contaminant migration management. The extraction of landfill gas (with subsequent control of off-site gas migration) and the removal of VOCs from the landfill gas/soil air environment will minimize VOC solubilization in the underlying groundwater. This, in turn, will permit cost efficient management of contaminant migration at the site.     

微正压气力输灰系统技术改进

对徐州发电厂7号炉微正压气力输送系统进、出料阀进行了技术改进,采用柔性阀板解决了卸灰装置磨损块的问题,系统可靠性大幅度提高,效果显著。     

正压气力除灰系统管道的设计及工程应用

正压气力除灰系统的管道设计原则是按照现场条件、系统布置来确定管长，综合考虑系统运行能耗和管道的造价来确定管径，以物料启动速度、输出管道速度为边界条件来确定变径点。以内蒙古某电厂为例，给出了具体设计计算方法和计算结果，为管道设计的工程应用提供了依据。     

Augmenting in-situ remediation by soil vapor extraction with six-phase soil heating

The use and performance of soil vapor extraction (SVE) as an in-situ remedial technology has been limited at numerous sites because of both geologic and chemical factors. SVE systems are not well suited to sites containing low permeability soils or sites contaminated with recalcitrant compounds. Six-phase soil heating (SPSH) has been developed by the Battelle Pacific Northwest Laboratories (Battelle) to enhance SVE systems. The technology utilizes resistive soil heating to increase the vapor pressure of subsurface contaminants and to generate an in-situ source of steam. The steam strips contaminants sorbed onto soil surfaces and acts as a carrier gas, providing an enhanced mechanism by which the contaminants can reach an extraction well. Full-scale applications of SPSH have been performed at the U.S. Department of Energy's Savannah River Site in Aiken, South Carolina; at a former fire training site in Niagara Falls, New York; and at Fort Richardson near Anchorage, Alaska. At each site, chlorinated solvents were present in low permeability soils and SPSH was applied in conjunction with SVE. The results of the three applications showed that SPSH is a cost-effective technology that can reduce the time required to remediate a site using only conventional SVE.     

Characterizing soils contaminated with heavy metals: A uranium contamination case study

To stem rising remediation costs for soils contaminated with hazardous metals, increased emphasis is being placed on the development of in-situ and ex-situ treatment technologies. Often, a lack of basic information on the chemical and physical characteristics of the soil and contaminants hampers treatability studies used to design these technologies. This article proposes and demonstrates a characterization program to meet these information needs, employing standard analytical techniques coupled with advanced spectroscopy and microscopy techniques. To support treatments involving physical separation strategies, the program uses standard analytical techniques to characterize the soil and the association of contaminants with different soil fractions (e.g., size and density fractions). Where chemical treatments are required, spectroscopy and microscopy methods are employed to yield quantitative information on the oxidation state and speciation of the contaminant. Examples demonstrate the use of measured soil and contaminant characteristics in the screening of alternative treatment technologies and in the selection of soils for use in treatability studies. Also demonstrated is the use of these characterization tools in the design and optimization of treatment strategies and in support of risk assessment determinations.     

燃煤锅炉干排渣配套气力输渣一体化系统的设计与应用

以华能大连电厂为例,阐述了干式排渣、气力输渣一体化系统的特点、优势及运行后的不足与对策,实践证明,此系统的应用,能达到燃煤电厂节能减排的环保目的.     

硫酸盐还原菌原位修复六价铬污染土壤

以FeSO₄化学还原法为对照,开展硫酸盐还原菌原位修复铬污染土壤的田间试验研究。试验结果表明:微生物法处理后,土壤中Cr(Ⅵ)含量从6.48 mg/kg降至0.95 mg/kg,下降率为85.33%,修复后的土地质量符合国家一类建设用地的标准;土壤浸出液中Cr(Ⅵ)质量浓度从0.162 mg/L降至0.004 mg/L,下降率为97.53%;土壤中硫酸根浓度略有降低,硫酸盐还原菌的丰度显著增加。微生物原位修复铬污染土壤的效果好于化学还原法。     

过硫酸钠-过氧化钙修复多环芳烃污染土壤

采用过硫酸钠-过氧化钙双氧化体系修复多环芳烃(PAHs)污染土壤.通过单因素实验考察了过硫酸钠浓度、过氧化钙质量分数和n(柠檬酸):n(硫酸亚铁)等对土壤中PAHs降解率的影响.通过响应面分析确定,在过氧化钙质量分数为2.7％、过硫酸钠浓度为0.62 mol/L、n(柠檬酸):n(硫酸亚铁)=1:1时,PAHs降解率最...     

Acetone and 2‐butanone creation associated with biological and chemical remediation of environmental contamination

Remediating environmental contamination by either biological or chemical methods typically results in the generation of temporary chemical intermediates as part of the process. These intermediate compounds may be related to either contaminant degradation pathways or reactions generated from the amendment itself. This article summarizes previously researched pathways and representative case studies discussing the authors' experience in generating relatively high concentrations of acetone and 2‐butanone (also referred to as methyl ethyl ketone [MEK]) during both biological and chemical treatments. Experience shows that even relatively high concentrations of acetone and MEK intermediates are quickly attenuated and prove not to be a hazard outside of the treatment area. © 2011 Wiley Periodicals, Inc.     

曝气强化非离子表面活性剂洗涤法修复柴油污染土壤

采用异位修复法,利用非离子表面活性剂洗涤柴油污染土壤,并在洗涤过程中曝气强化。考察了洗涤效果的影响因素,并通过表面张力和接触角的测定探讨了洗涤机理。实验结果表明:曝气对污染土壤中柴油的洗脱有强化作用,可提高洗脱率10%~20%;3种非离子表面活性剂的洗脱效果优劣次序为聚氧乙烯月桂醚(Brij-35)曲拉通X-100(TX-100)吐温-80(Tw-80);在表面活性剂浓度为1倍临界胶束浓度、曝气量为7.5 L/min、洗涤时间为60 min、洗涤液pH为11.0的优化条件下,Brij-35对柴油的洗脱率达77.4%,污染土样的含油率从7.0%降至1.6%,接触角从24.12°降至6.65°,可基本恢复土壤的亲水性;洗涤液的表面张力随表面活性剂浓度的增加而降低,但不受洗涤液pH的影响。     

Modeling natural attenuation of petroleum hydrocarbon contamination using alternate electron acceptors: Case study comparing bioplume iii with BIOSCREEN

Natural attenuation holds great promise as a cost‐effective means of remedying groundwater contamination at petroleum spill sites: this is particularly true at sites with sufficient background concentrations of alternate electron acceptors (nitrate and/or sulfate). The study reported in this article compared the results of a new Environmental Protection Agency (EPA) numerical model (BIOPLUME III) with an updated EPA analytical model (BIOSCREEN Version 1.4) used to predict natural attenuation at an underground fuel spill site in Oklahoma. High background sulfate concentrations were shown to result in unrealistic predictions from both BIOSCREEN and BIOPLUME III. BIOSCREEN could be easily used with a data set not significantly enlarged from that used in a routine leaking fuel tank investigation. BIOPLUME III was much more difficult to use and did not yield reliable results. Results of this study indicate that the additional complexity of the BIOPLUME III model is not justified for simple sites.