电子垃圾重金属污染及防治对策研究

随着信息产业的飞速发展,电子产品更新换代加速,电子垃圾飞速增长,电子垃圾中的重金属对环境造成了越来越严重的污染.本文回顾了广东贵屿与浙江台州两大电子垃圾回收拆解区重金属污染的现状,分析了电子产品原材料、加工工艺和电子垃圾不当回收导致重金属污染的原因,提出了依靠政策法规引导、借鉴国外先进经验、进行电子垃圾回收处理产业化发展的相应防治对策,以期能改善电子垃圾导致的重金属污染.     

城市垃圾重金属污染及其治理研究进展

城市垃圾重金属污染及其治理是当前城市发展过程中急需解决的重大课题。本文分别从城市垃圾中重金属的来源、重金属污染及治理现状等方面综述了目前城市垃圾重金属污染方面的研究进展,指出了当前研究中存在的问题和今后的发展方向。     

农村遭遇面源污染危机

臭气肆虐,垃圾乱飞,已经成为部分农村的常见现象."城里人富了,产生的垃圾都运到了村子里,农村变得越来越脏".其实,这种观点只关注了一种污染现象.随着农村经济发展,更为严重的面源污染也在威胁农村,后者的破坏面可能更大.     

三峡库区农村填埋垃圾渗滤液污染物含量评价

为了研究农村填埋垃圾渗滤液污染物含量和组成,选取了三峡库区10个垃圾填埋场渗滤液作为研究对象,对其无机阴离子、重金属含量及组成成分和pH值进行了分析.结果发现,垃圾填埋场渗滤液p H值均呈碱性,同时,SO_4~(2-)浓度均普遍高于Cl~-浓度.此外,受氧化还原电位和p H值的影响,呈现出NO_3~--N浓度NO_2~--N浓度的分布趋势.通过指数和单因子评价法对填埋垃圾的重金属含量进行了分析和评价.结果表明,Cr无污染现象,但Cd污染现象普遍十分严重,Pb、Zn和Cu污染则在不同的地点呈现出空间差异性.研究表明,三峡库区农村填埋垃圾特异性高,污染物来源构成差异性大.     

河源农村垃圾污染现状调查及其处理对策

随着社会的进步和发展,农村生活方式也呈现多样化和现代化,然而,产生越来越多的生活垃圾却不容小视。农村生活垃圾污染着人们赖以生存的环境,影响了社会主义新农村的建设步伐,威胁着人们的身体健康。本文通过对河源市广大农村垃圾污染现状进行调查与分析,探讨有效处理的对策,从而使得农村垃圾的管理走向规范化和现代化。     

固体生活垃圾无废精制工艺

人类生存环境的恶化,使人们对资源的二次利用越来越感兴趣.固体生活垃圾是巨大的潜在能源,不少是取之不尽的可重复利用的物资,科学发展已使变废为宝成为现实.处理固体生活垃圾常用焚烧、深埋和腐熟处理法.处理大量固体生活垃圾时常采用焚烧法,该法既不符合资源保护要求,也会对环境造成污染;垃圾深埋会污染土壤、地下水、地表水和空气,对周围环境构成严重威胁;堆肥法可得混合肥料,但由于清除其中的重金属盐类很棘手,难于推广.这三种方法都不能充分利用垃圾中的有效成分.     

我国农村环境管理体制探析

<正>近年来,在城市环境日益改善的同时,农村环境污染问题越来越凸显,在工业化、城镇化程度较高的东部发达地区的农村尤为突出。点源污染与面源污染共存,生活污染和工业污染叠加,各种新旧污染相互交织,工业及城市污染向农村转移,农村环境污染问题对农村社会发展和农民福利改善的阻碍也将日趋明显。具体污染现状是:农村生活污水和垃圾排放量大,目前全国农村每年产生生活污水约90亿吨,生活垃圾约2.8亿吨,而且处理率较低。     

我国土壤重金属污染现状及治理战略

随着工业时代的发展,越来越多的工业活动使得我国土壤资源受到严重的污染破坏,各种工业废水废气和生活垃圾的降解压力使得土壤污染越来越严重,而土壤的污染治理关系到国计民生的农作物生长问题,下面就将在重金属污染方面进行现状分析,探索治理方法。     

都匀市垃圾填埋场周围土壤重金属含量调查研究

本文以都匀市垃圾填埋场周围农田土壤为研究对象,通过调查填埋场周围农田土壤重金属含量。结果表明,该地区农田土壤受到重金属严重污染,并且随垃圾填埋场与农田距离的增加,土壤重金属舍量呈现出降低趋势,海拔高于垃圾填埋场的农田受重金属污染程度较轻。农田土壤受重金属严重污染很大程度上是垃圾填埋场的影响。     

“收运体系”能否成为“治本”良药

正"户收集、村集中、镇转运、县处理",这是目前农村垃圾收运处理的基本模式,然而这套模式能否彻底解决农村垃圾困局呢?随着农村物质生活水平的提高,农村生活垃圾的数量在不断膨胀,大多数村落垃圾随意倾倒在村边,使农村面源污染越来越严重,垃圾的收集处理已成为困扰农村发展的一个棘手问题。为全面推进农村垃圾处理工作,2011年广东省人民政府(以下简称省政府)将兴宁、鹤山、新兴     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.