基于MCDA的沙漠地区污染场地地下水修复技术优化方法

针对近年来频频出现的污染企业向沙漠地区地下排污造成地下水污染这一问题,以腾格里沙漠地区某化工厂地下水污染为研究案例,提出适合沙漠地区地下水污染修复技术的优选方法。在综合考虑修复技术的经济、技术和社会效益基础上,利用层次分析法建立修复技术优化指标体系,运用多准则决策分析模型（multiple criteria decision analysis,MCDA）中的消去和选择转换法（ELECTREII）对修复技术组合进行优选排序,确定适合该地区的最优修复技术方案。结果表明,5种地下水修复备选技术中可渗透反应墙、抽出-处理、监测自然衰减技术较为理想,综合考虑该污染场地特征以及地下水治理要求,得出最佳修复方案为：对高污染浓度区域采用抽出-处理技术+可渗透反应墙技术联合修复;对于低污染区域采用监测自然衰减技术。该优化方法可为沙漠地区地下水污染修复技术的选取提供借鉴。     

斯里兰卡CKDu病区地下水源水质分析及纳滤膜技术在该地区饮用水处理中的应用

针对斯里兰卡CKDu病区饮用水安全保障的需求,分别在雨季和旱季调查了斯里兰卡CKDu病区北中省Anuradhapura地区的地下水水质。结果表明,地下水中硬度和F⁻的平均质量浓度分别超过250.0 mg·L⁻¹和1.49 mg·L⁻¹,均高于斯里兰卡饮用水标准(SLS 614-2013),且溶解性有机物(DOC)平均质量浓度大于4.0 mg·L⁻¹。在斯里兰卡Anuradhapura地区Sirimapura村援建以纳滤(NF)膜技术为核心的地下水源饮用水站,于2018年9月投入运行。运行结果表明,NF水站可有效去除地下水的硬度、F⁻和DOC,硬度、F⁻的平均截留率分别达80%和85%,DOC可完全去除,产水水质满足斯里兰卡国家饮用水水质标准(SLS 614-2013)。NF水站具有易于操作、便于维护、产水水质优异等优点,产水呈弱碱性(pH=7.3),且可保留部分对人体有益的矿物质。     

Metal concentrations and mobility in marine sediment and groundwater in coastal reclamation areas: a case study in Shenzhen, China

The concentrations of metals in the buried marine sediment and groundwater were differently affected by land reclamation. Nine metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in sediment and coastal groundwater from reclamation areas in Shenzhen were examined. The gradually decreased concentrations (V, Cr, Mn, Ni, Cu, Zn) in sediment and relatively higher concentrations (V, Cr, Mn, Co, Ni, Cu and Cd) in groundwater within reclamation areas were observed. The increase of V, Cr, Mn, Ni, Cu and Cd concentrations in groundwater within reclamation areas subsequently after land reclamation should be resulted from the mobilization of these metals accumulated in the sediment. These metals appear to be easily mobilized from solid phase to solution phase after reclamation. The physico-chemical changes such as reduction in pH and salinity in water environment induced by land reclamation appear to be responsible for metal mobility in the sediment-groundwater system.     

Hydrochemistry of urban groundwater, Seoul, Korea: the impact of subway tunnels on groundwater quality

Hydrogeologic and hydrochemical data for subway tunnel seepage waters in Seoul (Republic of Korea) were examined to understand the effect of underground tunnels on the degradation of urban groundwater. A very large quantity of groundwater (up to 63 million m³ year^− 1) is discharged into subway tunnels with a total length of 287 km, resulting in a significant drop of the local groundwater table and the abandonment of groundwater wells. For the tunnel seepage water samples (n = 72) collected from 43 subway stations, at least one parameter among pathogenic microbes (total coliform, heterotrophic bacteria), dissolved Mn and Fe, NH₄⁺, NO₃⁻, turbidity, and color exceeded the Korean Drinking Water Standards. Locally, tunnel seepage water was enriched in dissolved Mn (avg. 0.70 mg L^− 1, max. 5.58 mg L^− 1), in addition to dissolved Fe, NH₄⁺, and pathogenic microbes, likely due to significant inflow of sewage water from broken or leaking sewer pipes.Geochemical modeling of redox reactions was conducted to simulate the characteristic hydrochemistry of subway tunnel seepage. The results show that variations in the reducing conditions occur in urban groundwater, dependent upon the amount of organic matter-rich municipal sewage contaminating the aquifer. The organic matter facilitates the reduction and dissolution of Mn- and Fe-bearing solids in aquifers and/or tunnel construction materials, resulting in the successive increase of dissolved Mn and Fe. The present study clearly demonstrates that locally significant deterioration of urban groundwater is caused by a series of interlinked hydrogeologic and hydrochemical changes induced by underground tunnels.     

基于支持向量机的地下水质量综合评价

提出基于支持向量机（SVM）机器学习算法的地下水质量评价模型。首先给出了训练样本生成和数据规范化处理的具体方法,然后采用支持向量机的多分类算法构建模型,并使用k折交叉核实方法对参数进行验证优化。最后通过实证分析,并与单因子指数法、模糊综合评价法和BP神经网络法的评价结果对比分析可知,该方法简便易行,评价结果客观且准确度较高,具有很强的实用性。     

基于模糊权物元理论的地下水水质评价模型构建及应用

在物元分析的基础上,结合模糊权重理论与层次分析方法,构建用于评价地下水水质的模糊权物元分析模型。应用此模型对徐州市的重要水源地——张集水源地的地下水水质进行了综合评价。选取数据较为完整的20个监测井的监测数据进行评价。结果表明,研究区的20个采样点水质为Ⅱ、Ⅲ级的占95%,绝大多数地下水水质较好,符合饮用水的要求。与投影寻踪法和模糊概率法的评价结果比较发现,得出的评价结果与以上2种评价结果基本一致。     

Levels and isomer profiles of Dechlorane Plus in the surface soils from e-waste recycling areas and industrial areas in South China

Dechlorane Plus (DP) is a highly chlorinated flame retardant. Levels of DP were measured in surface soils from e-waste recycling areas and industrial areas in South China. Higher DP levels were found in e-waste recycling areas (undetectable-47.4 ng/g) than those in industrial areas (0.0336-4.65 ng/g) in South China. The highest DP concentration (3327 ng/g) was found at the e-waste recycling site in Qingyuan, while DP levels fell dramatically with increasing distance away from the recycling site, suggesting that the e-waste recycling activities are an important source of DP emissions. The mean ratios of anti-DP to total DP (f_anti) for different sampling areas ranged from 0.58 to 0.76 and showed no significant difference from the ratio for the technical DP products (t-test, p > 0.05). Further intensive studies are needed to investigate the process of DP degradation and its degradation products.     

因子分析及其在河网水质综合评价中的应用研究

对因子分析方法在天然水体水质评价中的应用进行研究,证明在数据较为缺乏的情况下,使用因子分析方法可以损失较少信息,减少评价指标,针对主因子进行分析,使水质评价结果更为合理和有效。同时,利用因子的得分值还可以将不同地区进行比较分析。应用因子分析对河网地区典型河流的水质状况进行分析,发现了增长潜力较大的主要因子,并对该地区的水质状况做出了符合实际的总体评价,表明因子分析在水质评价中具有重要应用价值。     

Natural and anthropogenic factors affecting the groundwater quality in the Nandong karst underground river system in Yunan, China

The Nandong Underground River System (NURS) is located in a typical karst agriculture dominated area in the southeast Yunnan Province, China. Groundwater plays an important role for social and economical development in the area. However, with the rapid increase in population and expansion of farm land, groundwater quality has degraded. 42 groundwater samples collected from springs in the NURS showed great variation of chemical compositions across the study basin. With increased anthropogenic contamination in the area, the groundwater chemistry has changed from the typical Ca–HCO₃ or Ca (Mg)–HCO₃ type in karst groundwater to the Ca–Cl (+ NO₃) or Ca (Mg)–Cl (+ NO₃), and Ca–Cl (+ NO₃ + SO₄) or Ca (Mg)–Cl (+ NO₃ + SO₄) type, indicating increases in NO₃⁻, Cl⁻ and SO₄²⁻ concentrations that were caused most likely by human activities in the region. This study implemented the R-mode factor analysis to investigate the chemical characteristics of groundwater and to distinguish the natural and anthropogenic processes affecting groundwater quality in the system. The R-mode factor analysis together with geology and land uses revealed that: (a) contamination from human activities such as sewage effluents and agricultural fertilizers; (b) water–rock interaction in the limestone-dominated system; and (c) water–rock interaction in the dolomite-dominated system were the three major factors contributing to groundwater quality. Natural dissolution of carbonate rock (water–rock interaction) was the primary source of Ca²⁺ and HCO₃⁻ in groundwater, water–rock interaction in dolomite-dominated system resulted in higher Mg²⁺ in the groundwater, and human activities were likely others sources. Sewage effluents and fertilizers could be the main contributor of Cl⁻, NO₃⁻, SO₄²⁻, Na⁺ and K⁺ to the groundwater system in the area. This study suggested that both natural and anthropogenic processes contributed to chemical composition of groundwater in the NURS, human activities played the most important role, however.     

基于聚类分析和水质标识指数的水质评价方法

为探讨一种适用于大尺度、多断面和长时间的水质评价方法,用层次聚类分析将2006~2008年海河5个监测断面的165个水质样本分为20组,并用方差分析验证了结果的可靠性。用综合水质标识指数表示水质样本的综合特征,与单因子评价法相比,该方法充分考虑了最差水质因子的影响,避免了单因子评价法以偏概全的缺陷,且分辨率高。将评价结果分解到各断面,结果表明:密云水库、官厅水库和于桥水库的水质处于II~III类水之间,可满足作为饮用水水源水的要求,三岔口断面大部分时间为IV~V类水,张家口八号桥断面全年有6个月以上水质属于劣V类。     

污灌区与非污灌区的地下水主要水质指标变化趋势及对比研究

通过对水文地质条件和天然条件下水质相似的一处非污水灌溉区地下水与一处污水灌溉区地下水水质的对比研究 ,得出污水灌溉区地下水水质变差主要是由化肥和污水灌溉共同引起的 ,且非污灌区地下水水质要好于污灌区的水质。污水灌溉对地下水的影响程度与化肥对地下水的影响基本相同。同时本文也独立地给出了污水灌溉和化肥对地下水水质的影响规律。     

基于电絮凝法处理矿区高浓度含氟地下水动力学分析

采用铝电极电絮凝体系对矿区高含氟地下水进行处理,研究了高氟浓度下电絮凝除氟过程,分别考察了电流密度、极板间距、进水氟质量浓度及pH对除氟效果和动力学常数的影响,并建立了电絮凝除氟动力学方程模型。结果表明：最佳除氟参数为电流密度为450 A·m⁻³,极间距为5 mm,pH为6.0~7.0;当进水氟质量浓度为12.1 mg·L⁻¹时,经60 min电絮凝除氟后可使进水氟质量浓度由12.1 mg·L⁻¹降为0.6 mg·L⁻¹以下,整个除氟过程遵循一级反应动力学模型且除氟动力学常数取决于电流密度、极板间距和进水氟质量浓度。絮体结构与成分分析表明,在pH=6.0~7.0条件下,电絮凝体系中主要形成的无定型羟基铝化合物使除氟效果达到最好,较高的进水氟质量浓度有助于提高铝离子利用效率。     

铁电絮凝产羟自由基氧化降解地下水中磺胺

为了揭示铁电絮凝(EC)过程中尚未被认识的羟自由基氧化机制,以磺胺污染的地下水为对象进行电絮凝降解研究。通过淬灭自由基、厌氧电絮凝和加Fe(III)盐等对照实验,探究反应体系是否存在羟自由基氧化机制;并对不同电解质、溶液pH、初始磺胺浓度、电流强度条件下的电絮凝降解磺胺效率进行了测定。研究结果表明：铁电絮凝处理磺胺废水反应体系存在羟自由基氧化降解磺胺机制;地下水中,阴离子对铁电絮凝氧化效果的影响较小。对模拟江汉平原含0.2 mg·L-1 As(III)和0.1 mg·L-1磺胺的地下水进行铁电絮凝处理,在30 mA的电流条件下,As(III)在4 h内的去除率达到100%,而磺胺达到68.6%。     

松花江水质的多元统计分析

采用主成分分析法、因子分析法对松花江干流11个断面的水质监测数据按照不同水期进行分析,研究了各水质参数的相关性并对污染来源及不同水期内反映水质的重要参数进行了初步探讨.结果表明,水中可生物降解污染物对水体DO有一定的影响,水体温度是控制耗氧性污染物降解的主要因素.枯水期NH3-N与生活污水排放有重要关系,且在TN中占有较高比例.丰水期NH3-N与挥发酚相关性增加,这可能与汛期内煤化工类企业排放不达标有关;平水期,NH3-N与NO3-N相关性增加,可能平水期的污染来源及负荷与其他水期有差别.通过因子分析发现,在不同水期有不同的水质参数影响水质,枯水期大肠杆菌、TP是反映水质的重要参数;丰水期NH3-N、TP、石油类、pH为影响水质的主要水质参数;平水期DO、TN、电导率是反映松花江水质状况的重要水质参数,应当针对不同水期的污染负荷构成制定相应的污染防治方案.     

Fe2+活化过硫酸钠原位修复氯苯污染地下水

通过建立土槽模型模拟实际污染场地,并采用Na2S2O8为氧化剂、柠檬酸螯合Fe2+为活化剂,研究了氯苯在地下水中的迁移分布规律、原位修复及其对地下水环境的影响。结果表明,氯苯在含水层水平纵向上的迁移作用大于横向迁移;随着时间的增加,地下水中氯苯浓度变化总趋势为先增加后减少并最终趋于稳定;随着迁移距离的增加,氯苯的浓度逐渐降低。柠檬酸螯合Fe2+活化Na2S2O8能够有效修复受氯苯污染的地下水和土壤;持续氧化36 h后,地下水和土壤中氯苯的去除率分别达到82.4%和80.3%。进一步研究发现,氧化处理后,出水的pH值基本稳定在3.5、SO42-浓度为88.7 mg/L,满足地下水Ⅱ类水质标准。     

江苏农村生活污水处理设施进水水质调查分析

为深入了解农村污水处理设施的实际进水水质特征,以江苏省20个村庄内生活污水处理设施的进水为研究对象,开展为期1年的水质监测。结果表明,设施进水水质呈季节性变化规律,污染物浓度1月份最高,7月份最低。进水主要污染物指标分布规律为：春夏秋冬四季化学需氧量（COD）低浓度范畴（COD≤ 100 mg·L-1）占样本总数的比例最大,分别为66.7%、68.4%、77.8%和40.9%;总磷（TP）浓度低于3 mg·L-1的样本数占总数比例最大,分别为春季53.3%、夏季63.2%、秋季66.7%和冬季36.4%。总氮（TN）与NH4+-N随季节变化规律相同,夏季处理设施进水中低浓度范畴（TN≤ 20 mg·L-1、NH4+-N≤ 15 mg·L-1）占总数比例最大,分别为42.1%、44.7%。冬季处理设施进水TN、NH4+-N浓度主要变化范围分别是40~85 mg·L-1和35~70 mg·L-1,属中高浓度范畴,占样本总数的36.4%和54.5%。设施进水C/N偏低,年均值为3.9;NH4+-N占TN比例较高,年均值为68.9%。农村生活污水处理设施的设计,应以设施进水端水质为基准,以确保出水水质达标和防止资源浪费。     

昆明市分流制排水区域污水厂进水水质特征的统计学分析

应用多元统计方法系统分析了昆明市某分流制排水区域污水处理厂进水水质特征.结果表明,95％保证率时,该污水处理厂进水BOD5、COD、SS、TN、NH3-N和TP质量负荷分别为11 100、30 000、39 400、2 000、1 600和390 kg/d.进水水质指标中除了SS和NH3-N之间无相关性外,其余各指标间显著相关(α＜0.01).进水SS分别与BOD5、TP、COD有较强的相关性,其Pearson相关系数分别为0.845、0.786和0.915,进水BOD5分别与TP、COD亦有较强的相关性,其Pearson相关系数分别为0.808和0.918.进水BOD5/TN值＞4和BOD5/TP值＞20的累积概率分别为35％和94％,表明该污水处理厂进水有机物浓度不能满足微生物反硝化的需求,但可满足生物除磷对有机物和磷的理论需求量.     

Development,hotspots and trend directions of groundwater salinization research in both coastal and inland areas: a bibliometric and visualization analysis from 1970 to 2021

Environmental Science and Pollution Research - As a global concern, the issue of groundwater salinization refers to the phenomenon of an increase in the overall chemical content over background...     

沿海地区城镇化与生态环境协调发展的时空分析

通过构建城镇化与生态环境协调发展的综合评价指标体系,运用熵值法、协调度模型,对2003—2012年中国沿海地区的城镇化与生态环境发展过程及其协调程度进行时空分析。结果表明:(1)沿海地区城镇化综合指数不断提高,空间城镇化年均发展速度快于人口城镇化,而人口城镇化又快于生活城镇化,经济城镇化最低,且呈现出明显的区域集聚性特征。(2)生态环境综合指数呈波动上升趋势,生态环境压力加大,城镇化地区面临的生态环境问题更多。(3)2003—2005年,城镇化与生态环境协调度等级为中度失调,2006—2012年为轻度协调。     

水质评价中模糊-集对分析法的改进

针对水环境的不确定性和模糊性,基于集对分析法和模糊理论相结合的评价模型已被广泛运用到水质评价当中。传统的评价模型在确定水质等级的复合算法中虽引入了权值的概念,但仍会出现指标浓度重复计算、信息丢失和指标权值的影响得不到体现等缺陷,具有局限性。针对这些缺陷,将基于加权后的内梅罗指数法思想应用于传统模糊-集对分析法中的复合算法上,考虑到加权内梅罗指数法兼顾极值的特性及计权性,通过取平均值和极值替代累加的方法来实现减小指标浓度重复计算的影响,同时加强复合算法中权值所占比重使得权值的作用得到充分体现。实验表明,改进的复合算法使得评价结果更为精确、客观。