污泥中重金属污染现状及处置方式研究

对城市污水处理厂污泥中重金属来源、危害及处置进行讨论。采用火焰原子吸收法及原子荧光法对某城市污水处理厂污泥中重金属进行测定,结果表明:Zn、Pb、Cr、Hg含量均符合我国《城镇污水处理厂污染物排放标准》污泥农用控制标准,Cd、Cu含量略高于该标准;依据重金属元素在污泥中的主要存在形态,讨论了污泥排放对环境的潜在风险;提出固定或沥滤处理可用于污泥处置,固定处理法相对经济,操作简便,更易推广。     

基于TCLP法的pH、盐度、粒径对尾矿重金属释放影响研究

以新疆伊犁2个铅锌尾矿库的铅锌尾矿为研究对象,以TCLP法为研究方法,通过改变TCLP法浸提剂的p H值和盐度及样品的粒径,研究尾矿重金属Pb、Zn、Cu、Ni、Cr在不同影响因素下的浸出情况,旨在说明p H、盐度、粒径对尾矿中重金属释放的影响,以期为尾矿重金属环境风险评估提供参考。研究结果表明2个铅锌尾矿中Zn和Pb含量较高,尾矿B环境风险较尾矿A大;酸性条件下重金属浸出远大于碱性条件下浸出,p H值降低促进2个尾矿重金属Pb、Zn、Cu、Ni、Cr的释放,盐度增加明显促进Pb的浸出,Cu的浸出随盐度增加呈微弱上升趋势,Ni、Cr和Zn的浸出随盐度变化较小;尾矿A中Zn和Pb的浸出随粒径减小而增大,铅锌尾矿样品粒径变化对Cr、Ni、Cu的浸出浓度影响不大。     

吉林省镍矿区玉米体内重金属累积分布规律及其与土壤重金属全量的关系

矿山开采和冶炼可对矿区土壤造成不同程度的重金属污染。为了明确吉林省镍矿区耕地土壤/植物体系中重金属的迁移累积规律,在吉林省镍矿区采集了27个区域的土壤和玉米植株样品。结果表明,吉林省镍矿区土壤p H为5.00~6.82,有机质的含量为2.79%~7.93%,部分采样点的Cd和Pb超出吉林省土壤背景值,大部分采样点的Cu和Ni超出吉林省土壤背景值,所有采样点的Zn超出吉林省土壤背景值。玉米籽粒中Cd和Pb未检出,玉米茎中Cd未检出,27个采样点中有23个采样点的玉米籽粒Ni含量超过我国粮食及制品中重金属限量标准(NY 861-2004),而仅有4个采样点的籽粒Zn含量超过我国限量标准,所有采样点的籽粒Cu含量明显低于我国限量标准。随土壤重金属全量增加,玉米根Cd,Cu,Ni,Pb和Zn含量均呈增加趋势,其中根Cd,Cu,Ni含量与土壤重金属Cd,Cu,Ni全量呈显著正相关,而根Pb和Zn含量与土壤重金属Pb和Zn全量相关性不显著。     

我国城镇污泥营养成分与重金属含量分析

我国城镇污水处理厂的污泥中含有大量营养成分,同时也含有重金属成分,对于污泥中营养成分和重金属的含量情况,汇总并分析了国内90个污水处理厂的污泥泥质数据后,得出结论:总体上城镇污水处理厂的污泥泥质是适合土地利用的,重金属风险由大到小排序为:Hg、Ni、Cd、Zn、Cu、Cr、Pb、As、B;建议在开展污泥土地利用工作的同时,应探索创新排水管理模式、污泥中重金属去除技术,以及土地利用模式。     

西安市生活污水厂污泥中重金属特性及再利用风险评价

通过评价西安市污水厂污泥理化性质、重金属含量和潜在生态风险,探究污泥再利用的可行性.分析了西安市7个具有代表性的生活污水处理厂污泥的基本理化性质和6种重金属(Cr、Cu、Ni、Pb、Cd和Zn)在不同时期的含量变化,并对污泥再利用做了可行性评价和潜在风险评价.结果 表明,各污水厂污泥除XA3污水厂Cd未达标外,其余污水...     

西宁市大气降尘中重金属的测定及其初步探讨

本文报道了火焰原子吸收法测定西宁市大气自然降尘中的重金属铜(Cu)、锌(Zn)、铅(Pb)、镉(Cd)、镍(Ni)。结果表明,西宁市自然降尘中含有较高的重金属,8个采样点平均含量(微克/克)为:铜(Cu)56.40,锌(Zn)307.0,铅(Pb)51.60,镉(Cd)5.50,镍(Ni)44.82。并结合降尘量对降尘中的重金属进行了初步探讨,作者认为降尘中重金属的测定对综合评价城市环境质量具有重要意义。     

熔融法处理垃圾焚烧飞灰过程中重金属回收效果评估

垃圾焚烧飞灰作为危险废物含有大量重金属。研究从飞灰中分离、回收有害重金属的相关技术能避免重金属污染的扩散,同时对飞灰的资源化再利用具有重要意义。利用高温熔融法处理飞灰,烟气处理系统采用预除尘系统、急冷降温系统及布袋除尘系统,富集烟气中重金属,并采用酸洗法对浓缩灰中重金属进行资源回收,结果表明:3种浓缩灰中Zn、Pb、Cu、Cd富集浓缩现象明显;酸洗处理时,浓缩灰中的Pb、Zn、Cu、Cd、Cr、Ni迁移至酸洗液的比例分别为79.14%、94.12%、87.85%、92.89%、67.68%、91.54%,上述重金属元素自液相迁移至沉淀的比例均达到98%以上,基本实现了酸洗液中主要重金属的全回收。     

低含油污泥固化处理技术研究*

针对辽河油田欢采水厂低含油污泥,采用固化处理方法,测定了固化剂用量对抗压强度的影响和促凝剂用量对固化时间的影响,得到含油污泥:固化剂:促凝剂最佳配比为100:12:1.5。对含油污泥固化块进行浸出液毒性监测,分析结果表明:含油污泥固化块浸出液中重金属Cu、Pb、Cr、As、Zn、Ni、Cd的含量明显降低,远低于GB5085.3-2007《危险废物鉴别标准浸出毒性鉴别》;浸出液中COD降低了77%。     

潍坊市大气颗粒物中重金属污染特征

为了解潍坊市大气颗粒物中重金属浓度特征及其来源,于2014年对环境空气中颗粒物进行采样,分析了不同粒径颗粒物上的重金属(Fe、Cd、Cr、Cu、Pb、Mn、As、Ni、Zn)含量。结果显示,可吸入颗粒物(PM_(10))、细颗粒物(PM_(25))中主要重金属为Fe、Zn、Pb、Cu、Mn。重金属Pb、Cd、Zn和Cu主要富集在PM_(25)上。重金属浓度一般表现为冬季最高,这可能是人为污染和气候共同作用造成的。通过富集因子和主因子分析,PM_(25)中Cu、Zn、Pb和Cd是人为源贡献的,冶金、电镀和燃煤是主要人为源。     

南京市PM_(2.5)中重金属含量分布及溶出规律研究

自2017年1～10月,采集南京市PM_(2.5)样品共计42批次,分析了Cu、Zn等9种重金属的含量分布及其溶出规律。结果表明,PM_(2.5)质量浓度呈现明显季节特征,冬季高,夏季低,年均值为41μg/m~3,与国家二级标准比超标17%。南京市PM_(2.5)中重金属总量高低顺序为Fe Zn Pb Mn Cu Cr As Ni Cd,其中As超出推荐限值19%。在模拟酸雨提取PM_(2.5)中重金属时,淋溶液pH是决定释放率的最主要因素,pH越低,释放率越高。用pH 5. 6的模拟酸雨淋溶液提取南京市PM_(2.5)样品,Cd、Zn、Mn的释放率超过60%,而Fe、Cr、Pb的释放率低于30%。     

Plant growth and uptake of mineral elements at an oily sludge landfarming site in Kuwait

Oily sludge landfarmed in Kuwait soil contains higher concentrations of certain elements than that of the untreated of, soil, e.g. S, Cu, Cr, Zn, Pb, Ni, Mo and V. The growth and elemental content of three different plants grown on a sandy soil previously treated with different concentrations of oily sludge were studied. Tested plants differed in their response to landfarmed oily sludge; ryegrass was the least affected followed by oats, then barley. Uptake of elements differed both qualitatively and quantitatively between test plants. In barley, Zn increased in plants cultivated in soil treated with oily sludge, whereas other metal concentrations were reduced or not affected, namely, Cu, Pb, Ni, V. The uptake of P was greater in plants grown on treated soil compared with those on untreated soil, whereas Na, Ca, K, were either reduced or unaffected. In oats, Zn, Ni, Cu, Pb, V, were not significantly changed. Uptakes of K, Ca, P, and Na in plants from treated soil were higher than that of the control. In ryegrass, heavy metal concentrations were either reduced or remained the same as that of the control. In all cases, concentrations of essential heavy metals and other true elements under investigation were still lower than the levels considered to be sufficient for micronutrients. Thus, the oily sludge was a source of certain micro-nutrients which were deficient in the sandy soil. Further, it appears that uptake and distribution of elements in plant tissues were both highly variable according to the plant, species, and the soil characteristics.     

Utilization of pulp and paper industrial wastes to remove heavy metals from metal finishing wastewater

Two pulp and paper industrial wastes, lime mud (LM) and recovery boiler ash (RB), have low moisture contents, low heavy metal contaminations and contain various carbonate compounds which contribute to a high pH. Metal finishing wastewater (MF-WW) has a low pH, high levels of TDS and high contaminations from Cr, Cu, Pb and Zn. The heavy metals from MF-WW were removed by sorption and precipitation mechanisms. LM gave better results in removing heavy metals from MF-WW than RB. At a reaction time of 45 min, the maximum removal efficiencies for Cr (93%) and Cu (99%) were obtained at 110 g L⁻¹ of LM, but at 80 g L⁻¹ for Pb (96%) and Zn (99%). Treatment with LM gives a higher sludge volume than with RB. However, the leachability of heavy metals from LM is lower. Leachability of heavy metals in the sediment for all selected treatment conditions is within government standards.     

Effect of liming on the distribution of heavy metals in untreated industrial sewage sludge produced in Pakistan for the cultivation of <Emphasis Type="Italic">Sorghum bicolor</Emphasis> (L.)

The recycling of sewage sludge on agriculture land represents an alternative, advantageous, disposal of this waste material. The aim of the present study was to evaluate the feasibility of using industrial sewage sludge, produced in Pakistan, as a fertiliser. Agricultural soil amended with 25% (w/w) sewage sludge with or without lime treatment was used for growing a variety of sorghum (PARC-SS-1). The mobility of the heavy metals (HMs) (Cd, Cu, Cr, Ni, Pb and Zn) and metalloid (As) in the untreated industrial waste water sewage sludge (UIWS) samples were assessed by applying a modified BCR (Community Bureau of Reference) sequential extraction procedure. The single extraction procedure comprised of the application of mild extractant (CaCl₂) and water for the estimation of the proportion of easily soluble metal fractions. The precision and accuracy of BCR was evaluated by using a certified reference material of soil amended with sewage sludge BCR 483. The plant available metal contents, as extracted by the deionised water and 0.01 M CaCl₂ solution and exchangeable fraction of BCR sequential, decreased with lime application in the range of 10–44% for As, Cr, Ni, Pb and Zn, except in the cases of Cd and Cu, where their mobility was increased by 10% and 24%, respectively. Sludge amendment enhanced the dry weight yield of sorghum and the increase was more obvious after liming up to 25%. The uptake of HMs were lower in test samples (3.2–21.8%), except for Cu and Cd, which was higher (4%), while they were below the permissible limit of these metals. The present experiment demonstrates that liming was important in factors facilitating the growth of sorghum in sludge-amended soil.     

Characteristic levels of heavy metals in soil profiles of automobile mechanic waste dumps in Nigeria

The characteristic levels of heavy metals (Cd, Cr, Cu, Pb, Ni and Zn) of soil profiles of automobile mechanic waste dumps were studied. The concentration of heavy metals decreased with the depth of the profile and lateral distance from the dumpsites. The levels found in this study exceeded background concentrations and limits for agricultural and residential purposes. The distribution pattern of heavy metals in the soil profiles were in the following order Pb > Zn > Cu > Cd > Ni > Cr. The mechanic waste dumps represent potential sources of heavy metal pollution to environment. The elevated levels of heavy metals in these soil profiles constitute a serious threat to both surface and groundwater.     

杭州城区河道底泥重金属污染及潜在生态风险评价

对杭州城区34条河道45个点位河道底泥进行采样,分析了pH及汞、砷、铅、铬、镉、铜、锌、镍等重金属含量,并进行污染及潜在生态风险评价。结果表明,监测点位的底泥为中性偏碱性,重金属含量分布不均,且范围波动很大,部分河道底泥重金属中汞、铅、镉、铬、锌、镍等有不同程度的超标,少数河道镉、铬、锌污染严重;按《农用污泥中污染物控...     

Biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions by cross-linked metal-imprinted chitosans with epichlorohydrin

Cross-linked metal-imprinted chitosan microparticles were prepared from chitosan, using four metals (Cu(II), Zn(II), Ni(II), and Pb(II)) as templates, and epichlorohydrin as the cross-linker. The microparticles were characterized by Fourier transform infrared spectroscopy, solid state (13)C nuclear magnetic resonance spectroscopy, and energy-dispersive X-ray spectroscopy. They were used for comparative biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions in an aqueous solution. The results showed that the sorption capacities of Cu(II), Zn(II), Ni(II), and Pb(II) on the templated microparticles increased from 25 to 74%, 13 to 46%, 41 to 57%, and 12 to 43%, respectively, as compared to the microparticles without metal ion templates. The dynamic study showed that the sorption process followed the second-order kinetic equation. Three sorption models, Langmuir, Freundlich, and Dubinin-Radushkevich, were applied to the equilibrium isotherm data. The result showed that the Langmuir isotherm equation best fitted for monolayer sorption processes. Furthermore, the microparticles can be regenerated and reused for the metal removal.     

Use of constructed wetland for the removal of heavy metals from industrial wastewater

This study was conducted to investigate the effectiveness of a continuous free surface flow wetland for removal of heavy metals from industrial wastewater, in Gadoon Amazai Industrial Estate (GAIE), Swabi, Pakistan. Industrial wastewater samples were collected from the in-let, out-let and all cells of the constructed wetland (CW) and analyzed for heavy metals such as lead (Pb), cadmium (Cd), iron (Fe), nickel (Ni), chromium (Cr) and copper (Cu) using standard methods. Similarly, samples of aquatic macrophytes and sediments were also analyzed for selected heavy metals. Results indicate that the removal efficiencies of the CW for Pb, Cd, Fe, Ni, Cr, and Cu were 50%, 91.9%, 74.1%, 40.9%, 89%, and 48.3%, respectively. Furthermore, the performance of the CW was efficient enough to remove the heavy metals, particularly Cd, Fe, and Cu, from the industrial wastewater fed to it. However, it is suggested that the metal removal efficiency of the CW can be further enhanced by using proper management of vegetation and area expansion of the present CW.     

Assessment of the Effectiveness of Environmental Dredging in South Lake,China

Environmental dredging is a primary remedial option for removal of the contaminated material from aquatic environment. Of primary concern in environmental dredging is the effectiveness of the intended sediment removal. A 5-year field monitoring study was conducted to assess the effectiveness of the environmental dredging in South Lake, China. The concentrations of total nitrogen (TN), total phosphors, and heavy metals (Zn, Pb, Cd, Cu, Cr, Ni, Hg, and As) before and after dredging in sediment were determined and compared. Multiple ecological risk indices were employed to assess the contamination of heavy metals before and after dredging. Our results showed that the total phosphorus levels reduced 42% after dredging. Similar changes for Hg, Zn, As Pb, Cd, Cu, Cr, and Ni were observed, with reduction percentages of 97.0, 93.1, 82.6, 63.9, 52.7, 50.1, 32.0, and 23.6, respectively, and the quality of sediment improved based on the criterion of Sediment Quality Guidelines by USEPA and contamination degree values (C_d) decreased significantly (paired t-test, p < 0.05). Unexpectedly, the TN increased 49% after dredging compared to before dredging. Findings from the study demonstrated that the environmental dredging was an effective mechanism for removal of total phosphorus and heavy metals from South Lake. Nevertheless, the dredging was ineffective to remove total nitrogen from sediment. We conclude that the reason for the observed increase in TN after dredging was likely ammonia release from the sediment impairing the dredging effectiveness.     

Total Contents and Sequential Extraction of Heavy Metals in Soils Irrigated with Wastewater,Akaki, Ethiopia

The Akaki River, laden with untreated wastes from domestic, industrial, and commercial sources, serves as a source of water for irrigating vegetable farms. The purpose of this study is to identify the impact of waste-water irrigation on the level of heavy metals and to predict their potential mobility and bioavailability. Zn and V had the highest, whereas Hg the lowest, concentrations observed in the soils. The average contents of As, Co, Cr, Cu, Ni, Zn, V, and Hg of both soils; and Pb and Se from Fluvisol surpassed the mean + 2 SD of the corresponding levels reported for their uncontaminated counterparts. Apparently, irrigation with waste water for the last few decades has contributed to the observed higher concentrations of the above elements in the study soils (Vertisol and Fluvisol) when compared to uncontaminated Vertisol and Fluvisol. On the other hand, Vertisol accommodated comparatively higher average levels of Cr, Cu, Ni, Zn, etc V, and Cd, whereas high contents of Pb and Se were observed in Fluvisol. Alternatively, comparable levels of Co and Hg were found in either soil. Except for Ni, Cr, and Cd in contaminated Vertisol, heavy metals in the soils were not significantly affected by the depth (0–20 and 30–50 cm). When the same element from the two soils was compared, the levels of Cr, Cu, Ni, Pb, Se, Zn, V, Cd at 0–20 cm; and Cr, Ni, Cu, Cd, and Zn at 30–50 cm were significantly different. Organic carbon (in both soils), CEC (Fluvisol), and clay (Vertisol) exhibited significant positive correspondences with the total heavy metal levels. Conversely, Se and Hg contents revealed perceptible associations with carbonate and pH. The exchangeable fraction was dominated by Hg and Cd, whereas the carbonate fraction was abounded with Cd, Pb, and Co. conversely, V and Pb displayed strong affinity to reducible fraction, where as Cr, Cu, Zn, and Ni dominated the oxidizable fraction. Cr, Hg, Se, and Zn (in both soils) showed preference to the residual fraction. Generally, a considerable proportion of the total levels of many of the heavy metals resided in non residual fractions. The enhanced lability is generally expected to follow the order: Cd > Co > Pb > Cu > Ni > Se > V and Pb > Cd > Co > Cu > Ni > Zn in Vertisol and Fluvisol, respectively. For the similar wastewater application, the soil variables influence the status and the distribution of the associated heavy metals among the different soil fractions in the study soils. Among heavy metals that presented relatively elevated levels and with potential mobility, Co, Cu, Ni (either soil), V (Vertisol), Pb, and Zn (Fluvisol) could pose health threat through their introduction into the food chain in the wastewater irrigated soils.