太原市某垃圾填埋场渗滤液及周边环境重金属污染及健康风险评估

探讨垃圾渗滤液、填埋场周围土壤和地下水中的重金属污染特征及其对生态环境和人体健康的影响.采集山西省太原市某垃圾填埋场和中转站冬夏季渗滤液、填埋场周边土壤和地下水样本,测定其中重金属含量;分析渗滤液中金属污染的季节性变化;利用健康风险评估模型,估计不同暴露途径下填埋场附近重金属污染对成人和儿童的健康风险.结果表明:(1)夏季填埋场渗滤液(陈年渗滤液)中重金属检出的种类较冬季多.夏季中转站渗滤液(新鲜渗滤液)中检出重金属种类比填埋场中的少,但其金属浓度(除Cr外)较高.(2)土壤重金属平均浓度的顺序为Cu>Cr>Zn>Pb>Ni>As>Hg,地下水中重金属平均含量顺序为Zn>Ni>Cu>Cr>Pb.(3)重金属污染对成人的非致癌总风险在安全阈值内,但对儿童的非致癌总风险接近安全阈值.重金属污染非致癌风险的主要暴露途径为经饮水摄入.有潜在健康风险的重金属主要是As、Pb和Cr.(4)重金属污染对人群的致癌总风险在安全阈值内,主要暴露途径为土壤口食摄入和呼吸吸入.垃圾填埋场和中转站渗滤液中重金属的种类和浓度不同;填埋场附近土壤和地下水中重金属的种类和浓度也有差异.填埋场附近环境的重金属污染对成人和儿童没有健康风险,但有潜在安全隐患.     

垃圾渗滤液原位反硝化研究

场外硝化-原位反硝化是垃圾填埋场氮管理的新途径.本文利用垃圾柱模拟生物反应器填埋场.研究了硝化渗滤液在填埋场内部的变迁及其对垃圾降解的影响.结果表明,硝化渗滤液回灌促进了填埋场垃圾降解,回灌的总氧化态氮(TON)被完全还原,反硝化为主要作用反应,最大TON负荷为28.6 mg(N)kg(TS)-1d-1.当负荷大于11.4 mg(N)kg(TS)-1d-1时,垃圾产甲烷受到抑制.抑制作用随负荷的增加而加强.在此过程中,反硝化逐渐代替产甲烷作用成为填埋场内垃圾降解的主要反应,产生气体以氮气为主,而非甲烷;硝化渗滤液与垃圾的长期作用也改变了填埋场的菌群结构.图5表1参18     

电感耦合等离子体原子发射光谱(ICP-AES)法测定垃圾渗滤液中的多种金属元素

本文参考GB 16889—2008《生活垃圾填埋场污染控制标准》和HJ 564—2010《生活垃圾填埋场渗滤液处理工程技术规范(试行)》,采用ICP-AES内标法测定了欧洲标准物质LGC-6177垃圾填埋场渗滤液中的10种金属元素的含量.实验结果表明,该方法线性相关系数良好r>0.99995,方法检出限低,精密度高,RSD小于2.0%,测定结果与标准值吻合,可同时测定垃圾渗滤液中的多种金属元素.     

城市垃圾处理的新动向——生物反应器填埋场技术

基于传统垃圾卫生填埋场的不足，介绍了生物反应器填埋场及其对垃圾和渗滤液中污染物的有效去除和阻滞机理，总结了生物反应器填埋场降低渗滤液污染强度、增加填埋场有效容积、提高产气量、加速填埋声稳定、降低垃圾处置成本等优势，概括了生物反应器填埋场设计和操作支行要素，提出了今后的发展方向。     

垃圾渗滤液中典型内分泌干扰物质(EDCs)细胞毒性分析

垃圾渗滤液的人类健康风险评估日益受到人们重视,也成为研究热点。本文采用一种新型高级氧化技术UV-Fenton处理渗滤液,并用人体乳腺癌细胞(MCF-7)评估处理过程中渗滤液原液以及渗滤液中典型内分泌干扰物质(EDCs)的细胞毒性,对垃圾渗滤液中EDCs的细胞毒性和变化规律进行了研究。结果表明渗滤液中的邻苯二甲酸二丁酯(DBP)、双酚A(BPA)、壬基酚(NP)是产生细胞毒性的主要物质,其毒性大小为DBPBPANP。在同样的氧化降解过程中显示出不同毒性变化规律,通过GC-MS分析,结果显示UV-Fenton过程中产生了大量的中间产物,这也是引起毒性变化的主要原因。实验结果也说明垃圾渗滤液细胞毒性可以通过UV-Fenton过程有效去除。     

温度对填埋垃圾渗滤液特征的影响

温度对填埋场有机垃圾的厌氧降解具有十分重要的影响,因而对填埋场渗滤液特征也产生重要的影响。文章通过在常温及29~45℃范围内设置的6个不同温度下的模拟垃圾柱降解对照试验,分析研究了温度对填埋有机垃圾渗滤液特征的影响。结果表明,在垃圾降解适宜的温度范围(29~45℃)内,较高的温度对渗滤液COD衰减具有较大的促进作用,而保持恒定的温度比升高温度对渗滤液COD衰减的影响更加显著,但温度对垃圾降解渗滤液中氨氮影响并不明显。     

城市垃圾填埋场抗生素抗性基因的污染特征

抗生素抗性基因是一种新型的环境污染物,为探究抗生素抗性基因在垃圾填埋场的污染特征,采集上海老港垃圾填埋场中固体垃圾和渗滤液样品,采用实时荧光定量PCR技术检测磺胺类抗生素抗性基因(sul1、sul2)、四环素类抗性基因(tetM、tetQ)、氨基糖苷类抗性基因(strB、aadA1)、大环内酯类抗生素抗性基因(ermB、mefA)、多重抗性基因(mexF)及I类整合子(intl1)等6类目标基因的丰度.结果显示,6类目标基因均在固体垃圾和渗滤液中检测到,丰度分别介于10~2-10~6、10~3-10~7/ng,且多重抗性基因、氨基糖苷类及磺胺类抗生素抗性基因检出丰度较高.在填埋场固体垃圾中,部分目标基因在1.5 m深处的丰度高于0.5 m深处;在渗滤液中,目标基因丰度和呈现老龄渗滤液大于新鲜渗滤液,部分目标基因在秋季的丰度大于春季.上述结果说明垃圾填埋场是抗生素抗性基因潜在的储存库,目标基因的丰度在垃圾填埋场中存在时空差异.(图8表2参41)     

北京市典型垃圾填埋场渗滤液中PFASs污染水平研究

全氟及多氟类化合物(Perfluoroalkyl and polyfluoroalkyl substances)作为一类新型污染物近年来已开始受到人们的广泛关注.本研究应用高效液相色谱-质谱联用的方法对北京市4个典型垃圾填埋场垃圾渗滤液中全氟化合物(PFASs)的含量进行研究分析,并着重对六里屯垃圾填埋场产生的垃圾渗滤液及其周边河流、底泥以及土壤进行监测取样,分析PFASs污染程度.结果显示,北京市垃圾渗滤液的PFASs总浓度在407.10—2982.25 ng·L~(-1)之间,主要的污染物为PFPeA(Perfluoropentanoic acid,全氟戊酸)、PFOA(Perfluorooctanoic acid,全氟辛酸)和PFOS(Perfluorooctane sulphonate,全氟辛烷磺酸盐),另对六里屯垃圾填埋场渗滤液中PFASs进行为期两年的分析,PFASs检出率为100%,总浓度为407.10—4275.53 ng·L~(-1),主要的污染因子为PFOA,浓度范围在132.87—431.00 ng·L~(-1).六里屯垃圾填埋场周围环境介质均检出PFASs,受纳河流与土壤污染程度较高,河流PFASs总浓度在5.33—176.05 ng·L~(-1)之间,土壤PFASs总浓度在0.10—169.05 ng·g~(-1)之间,河水底泥污染程度较低,平均PFASs浓度为1.91 ng·g~(-1),表明经处理的垃圾填埋场渗滤液排放会对周围环境造成PFASs污染.     

生物反应器填埋场稳定技术

通过模拟实验研究了污泥接种、回灌前对渗滤液进行加热、不同的渗滤液回灌频率对生物反应器填埋场稳定进程的影响。研究表明，污泥接种、回灌前对渗滤液进行加热、较高的环境温度均有利于生物反应器填埋场快速稳定，垃圾填埋前期较低的渗滤液回灌频率有助于生物反应器填埋场快速进入产甲烷阶段，后期较高的渗滤液回灌频率则有利于填埋垃圾较快稳定。     

垃圾填埋场及周边水系中汞污染调查

对上海老港垃圾填埋场渗滤液、地下水和地表径流水监测分析表明：渗滤液中的汞主要为以颗粒态汞(S-Hg)形式存在，污水处理系统可以使颗粒态汞(S-Hg)随颗粒物沉积到底泥中，但是对可溶态汞(D-Hg)去除没有明显作用；芦苇湿地可以有效地吸附和吸收渗滤液中各种形态汞，使汞浓度降到一个较低的水平；对地下水和地表水的分析结果显示，地下水基本没有受到汞污染，而地表水受到一定程度的污染。     

活性污泥在渗滤液循环处理中的作用

渗滤液是垃圾填埋场产生的一种含有高浓度污染物的废水，它对环境造成的污染已经引起了人们的关注。渗滤液的处理方法很多，其中渗滤液循环法以其投资小、运行费用低、能加速填埋场稳定化进程等特点而倍受关注。利用活性污泥引入微生物，是在渗滤液循环基础上提出的一种新的设想，通过实验研究结果显示：加入干污泥循环可使渗滤液的COD由最高值2275mg／L降为67lmg／L．加入湿污泥循环可使渗滤液COD由最高值2075mg／L降为82lmg／L；而单纯进行渗滤液循环只使渗滤液的COD由最高值23llmg／L下降到l386mg／L。     

Evaluation and remediation of organics,nutrients and heavy metals in landfill leachate – a case study in Beijing

Leachate pollution in landfill sites is a major source of environmental concern. This study evaluates organics, nutrients and heavy metals in a landfill site in Beijing, and introduces a method combining coagulation–flocculation with filtration for the advanced treatment of leachate. The results confirm that COD_Cr, TN, NH₄⁺ ? N, TP, Mn and As in leachate treated by an anaeobic–oxic biological method are unable to meet discharge or surface water quality standards. When treated with coagulation–flocculation combined with filtration under optimal conditions (cationic polyacrylamide dosage of 8.0 mg/L; polyaluminium chloride dosage of 350 mg/L; 0.4–0.6 mm ceramsite media in the filtration process), the residual NH₄⁺? N, TN, Mn and As in the leachate meet the maximum allowed values for landfill leachate discharge or surface water quality standards in China; the exceptions are chemical oxygen demand and total phosphorus. Leachate treatment processes could be further strengthened or improved.     

Identification and assessment of water pollution as a consequence of a leachate plume migration from a municipal landfill site (Tucumán,Argentina)

Landfills constitute potential sources of different pollutants that could generate human health and environmental problems. While some landfills currently work under the protection of a bottom liner with leachate collection, it was demonstrated that migration could take place even yet with these cautions. The purpose of this paper is to assess the pollution caused by a leachate plume from a municipal landfill that is affecting both groundwater and surface waters. The research was carried out at Pacará Pintado landfill in northwestern Argentina. Analysis of water samples indicates that leachate is affecting groundwater under the landfill area and an abandoned river channel hydraulically connected. In the center of the landfill area, the plume is anoxic and sulfate, nitrate, iron and manganese reduction zones were identified. Leachate plume presented high concentration of organic matter, Fe, Mn, NH₄ ⁺, Cl^? and Cr reaching an extension of 900 m. The presence of a leachate plume in a landfill site with a single liner system implies that the use of this groundwater pollution control method alone is not enough especially if permeable sediments are present below.     

垃圾渗滤液组合工艺处理技术

针对垃圾渗滤液氨氮浓度高、COD浓度高、难降解物质含量高的特点,研究了MAP脱氮-生物处理-混凝组合工艺,考察了不同单元的作用及影响处理效果的因素。试验结果表明,高浓度的垃圾渗滤液经该优化组合工艺处理,污染物的去除率为COD97.5%、BOD599.2%、NH4-N87.2%、E26075.3%。除NH4-N外,其余指标均达到了生活垃圾填埋污染控制标准中规定的二级排放标准值。     

Phytoremediation of landfill leachate using Pennisetum clandestinum

Landfills are still the most widely used solid waste disposal method used across the world. Leachate generated from landfill areas exerts environmental risks mostly on surface and groundwater, with its high pollutant content, most notably metals, which cause an unbearable lower water quality. During dumping or after the capacity of the landfill has been reached, a decontamination and remediation program should be taken for the area. This study was conducted to assess the capacity and efficiency of Pennisetum clandestinum, a prostrate perennial plant, to accumulate chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), zinc (Zn) and lead (Pb). Leachate, taken from the Sofulu Landfill Site, was given to Pennisetum clandestinum for 180 days, in 3 dilution sets as 1/1, 1/2 and 1/4, in batch configuration. An additional control set was also installed for comparison. Results showed that, even though the metal content of soil had risen, plants accumulated 2 to 8.5 times higher concentrations than the control set. It is important to see, the plant showed almost no stress symptoms even if the set was fed by pure leachate. Pennisetum clandestinum was observed to accumulate metals mostly in the upper bodies, excluding Fe and Cu. 76% of accumulated Cr, 85% of Ni, 66% of Zn and 100% of Pb was observed to accumulate in above-ground parts, where only 20% of Cu and 4% of Fe was accumulated. Due to the high pollution tolerance of Pennisetum clandestinum, makes this plant suitable for decontamination and remediation of landfill sites.     

垃圾渗滤液对土壤铁锰有效性及地下水质的影响

受垃圾渗滤液影响,垃圾场周边土壤有机物含量增加。试验结果显示,随着土壤有机物含量的增加,土壤中有效态铁锰含量增大。垃圾场周边土壤中渗滤液有机物和金属铁锰共存时,大量的有机物质能活化土壤中的铁锰,增加其有效性,增强其在土壤中的迁移能力。从而造成垃圾场地下水较严重的铁锰污染。     

生活垃圾堆填区周边土壤的性状变化及其污染状况

对北京西郊某垃圾堆放场周边土壤的污染状况进行了分析研究。结果表明，受垃圾渗滤液的浸蚀影响，垃圾区周围土壤酸性增大，养分含量增高；垃圾区土壤的重金属含量明显高于对照区土壤，表明垃圾区周围土壤已受到渗滤液的重金属污染，土壤性状发生明显变化。     

垃圾填埋场渗滤液回流处理技术研究进展

垃圾渗滤液回流处理后，CODcr去除率最高达95％，在半好氧状态下NH3-N质量浓度降低至10mg/L几以下，渗滤液水质得到改善；渗滤液回流增加了湿度，使有机物的降解速率加快；渗滤液同流处产甲烷速率是不回流处产甲烷速率的2倍多：渗滤液回流处的总沉降幅度可达填埋场深度的20％，而不回流处仅为8％。回流处理技术分为直接回流至垃圾层、表面喷灌或浇灌至填埋场表面、地表下回流或内层回流技术。在填埋场处于产酸阶段早期，回流的渗滤液量宜少不宜多：在产气阶段则可逐渐增加。应将稳定化程度高的垃圾层区(产甲烷区)排出的渗滤液回流至新填人的垃圾层(产酸区)，将新垃圾层所产生的渗滤液回流至老的稳定化区。通过控制垃圾的组成、回流的时间、渗滤液的pH值等手段可改善回流处理效果。     

Development and prospects of municipal solid waste (MSW) incineration in China

With the lack of space for new landfills, municipal solid waste (MSW) incineration is playing an increasingly important role in municipal solid waste management in China. The literatures on certain aspects of incineration plants in China are reviewed in this paper, including the development and status of the application of MSW incineration technologies, the treatment of leachate from stored MSW, air pollution control technologies, and the status of the fly-ash control method. Energy policy and its promotion of MSW-to-energy conversion are also elucidated.