Heavy metal removal within pilot-scale constructed wetlands receiving river water contaminated by confined swine operations

Three parallel pilot-scale surface flow constructed wetlands were employed to investigate heavy metal removal receiving river water contaminated by swine confined-housing operations in Taiwan. Wastewater from swine operation contained elevated levels of copper and zinc due to their abundance in feed. Two macrophytes, namely cattail (Typha latifolia) and reed (Phragmites australis), were planted to observe their heavy metal removal efficiency. Significant total recoverable copper and zinc reduction for three tested wetlands were 80 and 91% for unplanted control, 83 and 92% for cattail, and 83 and 92% for reed wetland systems. Acid-soluble forms were 56 and 86% of total recoverable influent metals for copper and zinc, respectively. More bioavailable zinc was subjected to releasing back to aqueous environment. Heavy metals entering the studied systems as insoluble forms were settling from water column. Concentrations of metals were higher in the vegetated sediments than in the non-vegetated sediments. The sequential extraction results of sediments indicated that most retained metals were in less mobile fractions. Most of metal uptake by vegetation remained in root portions. Translocations of both copper and zinc for tested macrophytes were not prominent. The metal species in incoming water and metal fractionations in sediment were demonstrated as the major factors to influence plant metal levels. The performance of the studied wetland systems can comply with local water criteria rendering for further water reuse.     

Copper (2+), Zinc (2+), and Nickel (2+) Uptake by Activated Sludge

Abstract

This paper reports the results obtained on copper, zinc, and nickel uptake by activated sludge in a completely mixed unit. Removal of these heavy metals from wastewater occurs by uptake and by precipitation, the latter being particularly important in the cases of copper and zinc. The amount of heavy metal taken up by the microorganisms at equilibrium varies with influent concentration for the three metals studied. The values obtained range from 2.3 mg/g VSS for copper at 1 mg/L in the influent to 57.4 mg/g VSS for nickel at influent 25 mg/L. Soluble metal removal from wastewater increases in percentage with influent concentration, being higher for copper and lower for nickel. Experiments with mixtures of these metals have also been carried out.     

A Comprehensive Insight into Tetracycline Resistant Bacteria and Antibiotic Resistance Genes in Activated Sludge Using Next-Generation Sequencing

In order to comprehensively investigate tetracycline resistance in activated sludge of sewage treatment plants, 454 pyrosequencing and Illumina high-throughput sequencing were used to detect potential tetracycline resistant bacteria (TRB) and antibiotic resistance genes (ARGs) in sludge cultured with different concentrations of tetracycline. Pyrosequencing of 16S rRNA gene revealed that tetracycline treatment greatly affected the bacterial community structure of the sludge. Nine genera consisting of Sulfuritalea, Armatimonas, Prosthecobacter, Hyphomicrobium, Azonexus, Longilinea, Paracoccus, Novosphingobium and Rhodobacter were identified as potential TRB in the sludge. Results of qPCR, molecular cloning and metagenomic analysis consistently indicated that tetracycline treatment could increase both the abundance and diversity of the tet genes, but decreased the occurrence and diversity of non-tetracycline ARG, especially sulfonamide resistance gene sul2. Cluster analysis showed that tetracycline treatment at subinhibitory concentrations (5 mg/L) was found to pose greater effects on the bacterial community composition, which may be responsible for the variations of the ARGs abundance. This study indicated that joint use of 454 pyrosequencing and Illumina high-throughput sequencing can be effectively used to explore ARB and ARGs in the environment, and future studies should include an in-depth investigation of the relationship between microbial community, ARGs and antibiotics in sewage treatment plant (STP) sludge.     

重金属对活性污泥微生物活性的影响

本研究采用简单活性污泥法,使用对重金属中毒较为敏感的脱氢酶活性和更贴近活性污泥实际情况的耗氧速率作为活性污泥微生物中毒的评价指标,研究了铅、汞、铜、锌、铬(Ⅲ)五种重金属对活性污泥中微生物活性的影响。研究结果表明,五种重金属对活性污泥中微生物活性均有抑制作用,当重金属浓度达到45 mg/L时,五种重金属对活性污泥有机物降解能力的抑制率分别达到45.52%,50.44%,61.51%,27.94%,26.19%;对活性污泥脱氢酶活性抑制率分别达到62.49%,82.43%,79.17%,60.41%,62.39%。五种重金属对活性污泥的毒性大小为:铜汞铅铬锌。     

衣藻对重金属生物吸附的实验研究

以衣藻为生物吸附材料,研究了它对重金属钴、铜、锌的生物吸附,并用Freundlich等温吸附方程对实验数据进行处理。结果表明衣藻对这三种金属吸附能力大小顺序为锌钴铜;农藻对重金属的吸附能力很强,可用衣藻来处理含重金属的废水。     

Self-assembled nanostructure of copper hydrogen phosphate with catalytic and antibacterial activity

The rapid development of antibiotic resistance poses a huge threat to human health. Copper-based materials is a promising alternative to the traditional antibiotics due to its high efficacy and low resistance potential for bacterial infections. In this work, three-dimensional flower-like copper hydrogen phosphate nanosheet assembled microspheres (CP-NSMSs) are synthesized through a hydrolysis-assisted synthetic method using fructose-1,6-diphosphate (FDP) as the organic phosphate source. The copper hydrogen phosphate nanosheets with high aspect ratio provide a large amount of sharp edges which could penetrate bacterial membranes, resulting in the death of bacteria. Furthermore, the as-prepared CP-NSMSs exhibit the high peroxidase-like activity producing a large amount of reactive oxygen species (ROS) to kill bacteria. Based on the in vitro bacterial growth experiments, our CP-NSMSs show an excellent sterilization effect against both Gram-positive and Gram-negative bacteria. Therefore, the CP-NSMSs synthesized using the FDP as an organic phosphate source is expected to be a promising antibacterial agent with minimum resistance potential.     

Electrodialytic remediation of soils polluted with Cu,Cr, Hg,Pb and Zn

Electrodialytic remediation of heavy metal polluted soil is a method which combines the technique of electrodialysis with the electromigration of ions in the polluted soil. Results from laboratory-scale remediation experiments of soil samples from three real contaminated sites with different heavy metals are presented. In the three cases it was possible to mobilize and reduce the amount of the pollutants in the soil. The pollutants were (1) copper and chromium, (2) mercury and (3) copper, lead and zinc. For a loamy sand polluted with copper and chromium it was possible to decontaminate the soil to an extent lower than the recommended critical values for metal concentration in soil. Parameters that were identified as important for the efficiency of the electrodialytic remediation method were pH in the soil, lime content and speciation of the heavy metal. ©1997 SCI     

A YSK-Type Dehydrin from Nicotiana tabacum Enhanced Copper Tolerance in Escherichia coli

Copper is an essential micronutrient for the maintenance of normal cell function but is toxic in excess. Dehydrins are group two late embryogenesis abundant proteins, which facilitate plant survival in harsh environmental conditions. Here, a YSK-type dehydrin, NtDhn17, was cloned from Nicotiana tabacum under copper toxicity and characterized using a heterologous expression system and in vitro or in vivo experiments and exhibited characteristics of intrinsic disorder during in vitro analyses. Heterologous expression of NtDHN17 enhanced the tolerance of E. coli to various metals, osmotic, and oxidative stress. NtDHN17 showed no Cu²⁺-binding properties in vivo or in vitro, indicating that metal ion binding is not universal among dehydrins. In vitro and in vivo experiments suggested that NtDHN17 behaved as a potent anti-aggregation agent providing strong protection to aggregated proteins induced by excess copper ions, an effect dependent on the K-segment but not on the Y- or S-segments. In summary, the protective role of NtDHN17 towards E. coli under conditions of copper toxicity may be related to anti-aggregation ability rather than its acting as an ion scavenger, which might be a valuable target for the genetic improvement of resistance to heavy metal stresses in plants.     

“长株潭”地区湘江底泥重金属含量调查研究

通过调查分析湘江＂长株潭＂段表层底泥的锌、铜、镉、铬、铅、汞、锰等重金属含量,将底泥样品中重金属的含量分别与土壤环境质量标准、污水排入城市下水道水质标准、以及生活饮用水卫生标准中重金属含量进行比较,从而发现重金属在湘江＂长株潭＂段的污染严重程度。根据调查结果分析,对湘江＂长株潭＂段底泥重金属污染问题提出减排含重金属废水,有关部门应关注底泥重金属含量变化,和修复河床表层重金属含量高的底泥等建议。     

The MexJK Multidrug Efflux Pump Is Not Involved in Acquired or Intrinsic Antibiotic Resistance in Pseudomonas aeruginosa,but Modulates the Bacterial Quorum Sensing Response

Multidrug efflux pumps are critical elements in both intrinsic and acquired antibiotic resistance of bacterial populations. Consequently, most studies regarding these protein machineries focus on this specific phenotype. Nevertheless, different works show that efflux pumps participate in other aspects of bacterial physiology too. Herein, we study the Pseudomonas aeruginosa multidrug efflux pump MexJK. Previous studies, using model strains lacking MexAB-OprM and MexCD-OprJ efflux pumps, support that MexJK can extrude erythromycin, tetracycline, and triclosan. However, the results here reported indicate that this potential increased extrusion, in a mutant overexpressing mexJK, does not alter the antibiotics susceptibility in a wild-type genetic background where all intrinsic multidrug efflux pumps remain functional. Nevertheless, a clear impact on the quorum sensing (QS) response, mainly in the Pqs-dependent QS regulation network and in the expression of Pqs-regulated virulence factors, was observed linked to mexJK overexpression. The production of the siderophore pyoverdine strongly depended on the level of mexJK expression, suggesting that MexJK might participate in P. aeruginosa pyoverdine-dependent iron homeostasis. All in all, the results presented in the current article support that the functions of multidrug efflux pumps, as MexJK, go beyond antibiotic resistance and can modulate other relevant aspects of bacterial physiology.     

The interaction between Cu,Pb, Zn and Ni in their biosorption onto polyurethane‐immobilised Sphagnum moss

The uptake of Cu(II), Pb(II), Zn(II) and Ni(II) was investigated both individually and from mixed metal ion solutions using Sphagnum moss biomass immobilised in a polyurethane support. The data were evaluated using the Langmuir isotherm equation, and sorption capacities were calculated for different concentration ranges. It was concluded that care must be taken in presentation and interpretation of results when this modelling approach is applied at low concentrations. Repeated metal loading cycles also gave lower values for sorption capacity compared with the maximum potential value, due to equilibrium effects. The uptake capacity for the different metals on a weight basis was in the order lead > copper > zinc > nickel, but on a molar basis this changed to copper > lead > nickel > zinc. Sorption from a multi‐component metal system showed that lead and copper competed equally for binding sites and much more effectively than zinc and nickel. Equations were derived to predict the percentage effect on a given metal ion of other metals in a multi‐metal system based their behaviour in the relevant single and binary systems. Copyright © 2005 Society of Chemical Industry     

硫酸工业含砷污泥中的重金属测定

以某硫酸企业含砷污泥为研究对象,采用现行的浸取方法处理该含砷污泥,并用原子荧光光谱法和火焰原子吸收分光光度法测定其浸出液中的砷和铅、镉、铜、锌等5种重金属含量.结果表明,含砷污泥中砷、铅、镉、铜4种重金属含量均存在超标现象,相对标准偏差在81.1%～103.5%之间,加标回收率在0.05%～0.64%之间.此分析方法简...     

磷酸锌中重金属对双组分聚氨酯防腐涂料性能的影响

以不同重金属含量的磷酸锌为原料制备双组分聚氨酯防腐涂料,运用傅里叶变换红外光谱仪（FTIR）研究了重金属对双组分聚氨酯防腐涂料固化速率的影响,利用盐雾性能研究了重金属含量对双组分聚氨酯涂料防腐性能的影响。结果表明,磷酸锌中的重金属含量越高,其制备的聚氨酯涂料固化速度越快,耐盐雾性能越差,耐冲击性能越差。     

Selective sorption of heavy metal on phosphorylated sago starch‐extraction residue

The phosphorylated sago starch‐extraction residue (P‐SR) was produced for the removal of heavy metal from wastewater. The phosphoric ester in the phosphorylated residue was evaluated by means of infrared microspectrometry and solid‐state NMR. In this study, the phosphorus contents of produced P‐SR, phosphorylated cellulose (P‐C), and phosphorylated sago starch were 31.7, 34.2, and 4.6 mg/g, respectively. The phosphorus contents of P‐C and sago starch were clearly different because of the difference of each structure. The maximum sorption capacities of heavy metals (cadmium, lead, copper, and zinc) in single heavy metal sorption on P‐SR were 0.20, 0.25, 0.36, and 0.24 mmol/g (Cu > Pb > Zn > Cd), respectively. On the other hand, the amount of sorbed heavy metals in coexisted heavy metal sorption on P‐SR followed the order of Pb > Cu > Cd > Zn that was different from the relations of maximum sorption capacities for individual heavy metals. The heavy metal sorption behavior in single and coexisted heavy metal solution for P‐SR were different and P‐SR showed the intrinsic heavy metal sorption affinity, called as selective sorption. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Bioavailability of Heavy Metals in Soil: Impact on Microbial Biodegradation of Organic Compounds and Possible Improvement Strategies

Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation), treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals.     

Emissions monitoring during coal waste wood co-combustion in an industrial steam boiler

Co-combustion tests were performed in a 13.8 MW_th industrial steam boiler, using Greek lignite from Ptolemais reserve, natural waste wood, MDF residues and power poles. Fuel blends were prepared by mixing single waste wood components with lignite in various concentrations. Oxygen concentration and emissions of CO, SO₂ and NO_x were continuously monitored, during the co-combustion tests. Gaseous and particulate samples were collected and analysed for heavy metals, dioxins and furans according to standard methods. The results showed that co-combustion is technically feasible provided that agglomeration problems could be confronted. Low emissions of toxic pollutants were obtained during the co-combustion tests, below the legislative limit values. The lowest values of dioxins and furans were observed during combustion of fuel blends containing MDF, possibly due to inhibition by some nitrogenous components in MDF. No direct correlation was found between emitted PCDD/F and metal compounds, especially copper. Among the measured metals in the flue gases, zinc was the most prominent, while iron was mainly observed in the solid ash samples.     

Subcellular Sequestration and Impact of Heavy Metals on the Ultrastructure and Physiology of the Multicellular Freshwater Alga Desmidium swartzii

Due to modern life with increasing traffic, industrial production and agricultural practices, high amounts of heavy metals enter ecosystems and pollute soil and water. As a result, metals can be accumulated in plants and particularly in algae inhabiting peat bogs of low pH and high air humidity. In the present study, we investigated the impact and intracellular targets of aluminum, copper, cadmium, chromium VI and zinc on the filamentous green alga Desmidium swartzii, which is an important biomass producer in acid peat bogs. By means of transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) it is shown that all metals examined are taken up into Desmidium readily, where they are sequestered in cell walls and/or intracellular compartments. They cause effects on cell ultrastructure to different degrees and additionally disturb photosynthetic activity and biomass production. Our study shows a clear correlation between toxicity of a metal and the ability of the algae to compartmentalize it intracellularly. Cadmium and chromium, which are not compartmentalized, exert the most toxic effects. In addition, this study shows that the filamentous alga Desmidium reacts more sensitively to aluminum and zinc when compared to its unicellular relative Micrasterias, indicating a severe threat to the ecosystem.     

Separation and recovery of heavy metals from concentrated smelting wastewater by synergistic solvent extraction using a mixture of 2-hydroxy-5-nonylacetophenone oxime and bis(2,4,4-trimethylpentyl) -phosphinic acid

Extraction and separation of copper, zinc, nickel, and cadmium from calcium and magnesium in concentrated smelting wastewater by synergistic solvent extraction using a mixture of 2-hydroxy-5-nonylacetophenone oxime (Mextral 84H) and bis(2,4,4 -trimethylpentyl)-phosphinic acid (Cyanex 272) in an aliphatic diluent (DT-100) was studied. The effects of extractant concentrations, equilibrium pH, organic-to-aqueous phase ratios, system temperature, and extraction and stripping efficiencies on the extraction performance of the heavy metals were investigated. Extraction of pH isotherms showed that addition of Cyanex 272 to Mextral 84H causes obvious synergistic shifts for zinc and cadmium and a slightly antagonistic shift for nickel. The separation factor of cadmium over magnesium was 155.7 and the ΔpH₅₀ values between the metals were over 1.00 pH units. Semi-continuous tests for the metals extraction, scrubbing, and stripping were conducted in a continuous extraction apparatus with conditions further optimized for separation of the metals. Nearly 100% of the copper and nickel and over 98% of the zinc and cadmium were recovered with less than 0.1 mg/L copper and nickel, 26 mg/L of zinc, and 10 mg/L of cadmium remaining in the raffinate. A process in which all valuable metals are extracted simultaneously and stripped selectively at optimal conditions is proposed that is entirely feasible for the separation of copper, zinc, nickel, and cadmium from calcium and magnesium in concentrated smelting wastewater. The study determines the fundamental parameters for the treatment of smelting wastewater by solvent extraction.