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某化工污染场地土壤与地下水污染特征分析 总被引:1,自引:0,他引:1
以我国南方某典型化工污染场地为研究对象,通过场地调查确定了研究区的主要污染物为六六六、苯、氯苯和二氯丙烷,并进一步分析了污染物在土壤和地下水中的分布特征。污染物在土壤中浓度主要以生产车间为中心向四周逐渐减小,浓度梯度较大;在垂向上已穿透潜水层,浓度峰值出现在潜水层的中下部。污染物在潜水层中的分布呈现出和土壤中相似的特征,并表现出向南迁移的趋势。污染物在承压水层中的浓度峰值点与土壤和潜水重合,受区域地下水流向的控制,呈现明显向北迁移的趋势。由于地表较厚亚黏土的存在,增强了承压水的防污性能,污染物主要被截留于亚黏土中。 相似文献
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本文根据土壤的净化机制,分别对主要污染物在土壤中的转化过程进行了分析,以了解不同条件下土壤对污染物的净化效果及对地下水的影响。探讨了土壤的净化功能在污水处理中的作用,力求进一步解决我国城市污水土地处理与利用问题。 相似文献
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存量污泥是我国目前环境治理的一大难点,其对周边大气、土壤及地下水造成了严重威胁,尤其存量工业污泥危害更为严重。以辛集某制革污泥堆场为例,探索了一套“垂直阻隔+真空预压/浅层固化+原位固化稳定化+水平阻隔”的工程设计方案,经工程验证实施效果良好,可用于存量污泥场地的原位修复。 相似文献
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有机肥结构特征对污染土壤Cd形态的影响 总被引:1,自引:0,他引:1
研究了以污泥和鸡粪为主要来源的两种不同有机肥主要组分和结构特征差异,结合吸附和土壤平衡试验,探讨了各组分对Cd吸附反应特征和土壤Cd形态分布的影响。结果表明:供试污泥有机肥含有较多的羧基,其最大络合量大于鸡厩肥;同时能更有效降低NH4NO3提取态Cd,但因为结合形态相对不稳定,因此导致EDTA提取态Cd有明显增加。而鸡厩有机肥含有更多π键,芳香化和腐熟化程度较高,与Cd吸附更稳定,在降低NH4NO3提取态Cd的同时也能降低EDTA提取态Cd。研究表明有机肥腐殖化、芳香化程度是影响其对重金属污染土壤修复与改良效果的主要因素。 相似文献
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含油污泥热解残渣吸附性能初探* 总被引:1,自引:1,他引:1
含油污泥热解残渣的处理和应用是石油石化企业生产领域急需解决的难题。以含油污泥热解残渣为研究对象,在对其进行无害化处理的基础上,对热解残渣的吸附性能进行了探讨。通过能谱分析可知,热解残渣由碳和无机元素组成,碳元素含量达36.92%;通过SEM电镜扫描、比表面积和孔结构等吸附性质表征研究,含油污泥热解残渣吸附性能优良,对含油污水中的石油类和COD有较好的去除作用。研究结果表明:含油污泥热解残渣可作为一种吸附材料,这项研究为含油污泥热解残渣的资源化利用提供了一条途径。 相似文献
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石油在其开采、加工和运输过程中,存在石油污染物的排放和溢出问题,污染土壤,严重危害生态环境和人体健康。生物炭因其独特性质,能够以多种方式修复石油污染的土壤。概述了生物炭的特性、去除土壤石油污染物的机理、修复石油污染土壤方式等,对污泥生物炭修复油污土壤未来研究方向进行了展望。 相似文献
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以某天然气净化厂为例,探讨地下水环境影响评价工作中的主要技术问题。以实例说明地下水环境影响评价工作等级划分、评价范围确定,项目的地下水环境现状调查。通过渗水试验和抽水试验,计算相关水文地质参数以了解场地包气带和含水层的防污性能。分析了地下水污染源项,通过计算确定事故工况下污染源源强,采用数值法预测模型,对水文地质参数进行分区,并对净化厂检修污水池、生化污水处理装置曝气调节池和事故污水池的泄漏情景进行预测。结果表明:该净化厂各装置单元在预测时限内,除污染源附近小范围外,各污染因子浓度均可满足相应的GB/T 14848—93《地下水质量标准》要求。根据项目所在区域的水文地质条件、环境保护目标敏感程度及评价结果,对厂址区、主体装置区、污水处理区等重点区域按GB/T 50934—2013《石油化工工程防渗技术规范》有关要求采取相应防渗措施。 相似文献
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利用城市污水厂剩余污泥制备生物炭吸附镉 总被引:2,自引:0,他引:2
利用城市污水厂剩余污泥制备生物炭并用于吸附重金属离子Cd2+,有利于城市污水厂污泥的处置,为污水中重金属的处理与处置和“碳减排”提供新的思路与方法。研究结果表明不同污水厂的污泥的最佳活化温度不同,昆明第一污水处理厂污泥最佳活化温度为300℃,第三、第五污水处理厂污泥为400℃;对于污水厂污泥制备的生物炭对镉的吸附量随着pH值的升高而增加;吸附模型拟和结果表明Freundllch模型在大部分温度下均具有比Iangrmuir模型有更好的相关性。 相似文献
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Morphological changes in flocs were elucidated by small-angle light scattering, free settling tests and microscopic observation to determine the effects of pre-hydrolysis (alkaline treatment and ultrasonication) on two sludges--primary raw sludge from the Malabar Sewage Treatment Plant, Sydney (sludge M) and biological sludge collected at the nitrogen removal unit of St Marys Sewage Treatment Plant in Sydney (sludge S). Ultrasonication or alkaline treatment released a marked amount of insoluble organic matter in a soluble form. The latter treatment was more efficient than the former. Meanwhile, the pre-hydrolyzed flocs had more compact structures than the original ones, as shown by their higher free-settling fractal dimension, lower areal porosity and smaller internal pores. In particular, alkaline treatment yielded flocs with more compact interiors than did ultrasonication. Such detailed structural information could not be elicited by monitoring the change in floc size. The greater resistance to mass transfer of the hydrolyzed flocs thus produced does not reduce the efficiency of subsequent digestion, indicating that the surface reaction rate on the solid surface might have dominated since the pre-hydrolysis steps modified the local chemical environment to promote digestion. 相似文献
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Transport of di(2-ethylhexyl)phthalate (DEHP) applied with sewage sludge to undisturbed and repacked soil columns 总被引:1,自引:0,他引:1
Municipal sewage sludge is often used on arable soils as a source of nitrogen and phosphorus, but it also contains organic contaminants that may be leached to the ground water. Di(2-ethylhexyl)phthalate (DEHP) is a priority pollutant that is present in sewage sludge in ubiquitous amounts. Column experiments were performed on undisturbed soil cores (20-cm depth x 20-cm diameter) with three different soil types: a sand, a loamy sand, and a sandy loam soil. Dewatered sewage sludge was spiked with 14C-labeled DEHP (60 mg kg(-1)) and bromide (5 g kg(-1)). Sludge was applied to the soil columns either as five aggregates, or homogeneously mixed with the surface layer. Also, two leaching experiments were performed with repacked soil columns (loamy sand and sandy loam soil). The DEHP concentrations in the effluent did not exceed 1.0 microg L(-1), and after 200 mm of outflow less than 0.5% of the applied amount was recovered in the leachate in all soils but the sandy loam soil with homogeneous sludge application (up to 3.4% of the applied amount recovered). In the absence of macropore flow, DEHP in the leachate was primarily sorbed to mobilized dissolved organic macromolecules (DOM, 30.3 to 81.3%), while 2.4 to 23.6% was sorbed to mobilized mineral particles. When macropore flow occurred, this changed to 16.5 to 37.4% (DOM) and 36.9 to 40.6% (mineral particles), respectively. The critical combination for leaching of considerable amounts of DEHP was homogeneous sludge application and a continuous macropore structure. 相似文献
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A model is described that may help to resolve uncertainty and controversy over the long-term consequences of sludge applications to arable land, especially with regard to the effects of sludge adsorption characteristics on trace metal solubility and bioavailability (e.g., the sludge "time bomb" or sludge "protection" hypotheses). Mass balances of organic and inorganic material derived from sludge and crop residues are simulated. Each pool has a potentially different adsorption affinity for trace metals, and this leads to changes in the adsorption capacity of sludge-amended soil that influence leaching and crop uptake. Model simulations were compared with measured changes in organic carbon and ethylenediaminetetraacetic acid (EDTA)-extractable cadmium contents in a clay loam soil following 41 years of sludge applications. The model adequately reproduced the data, although discrepancies in the vertical distribution of Cd were attributed to the effects of macropore transport and root-uptake driven recirculation. A Monte Carlo sensitivity analysis demonstrated that the most important parameters affecting leaching and crop uptake were the Cd loading and parameters controlling adsorption, especially the partition coefficient for sludge-derived inorganic material and the exponent regulating the effect of pH on sorption. Scenario simulations show that no general conclusions can be drawn with respect to the validity of the sludge "time bomb" and sludge "protection" hypotheses. Either may occur, or neither, depending on three key system parameters: the ratio of sludge adsorption capacity to the initial adsorption capacity of the soil, the proportion of the sludge adsorption capacity contributed by the inorganic fraction, and the sludge Cd loading. 相似文献
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绩效评价是地方政府污水治理工作的重要但仍很薄弱的环节。本研究基于综合水资源管理(IWRM)目标原则开发了污水治理绩效综合评价指标体系,确定了指标权重,并对浙江省污水治理绩效进行了实证研究。结果表明,污水治理关键是改善自然水体功能。当前浙江省污水治理绩效总体良好,但存在污水处理投资项目运转效率差、农田污灌比重高、东部沿海市污水治理效果不理想等问题。建议今后浙江省污水治理工作应在继续提高自然水体功能的基础上,提高污水处理设施运转效率,加强农田水污染防治,并强化对东部沿海市区污水治理支持力度。 相似文献