Zeolite and fungi’s flocculability of simulated wastewater containing heavy metal ions or phosphorus

This paper focuses on the flocculability of simulated wastewater containing heavy metal ions (Fe3+, Cd2+) or phosphorus by zeolite, microbial flocculants (MBF) produced by Aspergillus niger and the composite flocculant composed of zeolite and MBF. The main results are presented as follows: zeolite was a good flocculant when the contamination of the three simulated wastewaters was low, but the treated water is of turbidness and the particles in it are hard to precipitate. The MBF have a good flocculability toward Fe3+ wastewater, as well as particulate matter. Significant changes in flocculability occurred after adding the composite flocculant in different simulated wastewa-ters, the best or least effect respective for Fe3+ and Cd2+ wastewater. The research we have done shows that the method by which the composite flocculant is used to treat the wastewater containing heavy metal ions or phosphorus provides important reference value for practical application.

Protein-derived nitrogen and sulfur co-doped carbon for efficient adsorptive removal of heavy metals

A nitrogen and sulfur co-doped carbon has been synthesized employing egg white as a sustainable protein-rich precursor.According to CHNS elemental analysis,N,S and O heteroatoms accounted for mass fractions of 3.66%,2.28%and 19.29%respectively,and the types of surface functionalities were further characterized by FT-IR and XPS measurements.Although the carbon possessed a smaller surface area(815 m2·g-1)compared to a commercial activated carbon(1100 m2·g-1),its adsorption capacity towards Co2+reached 320.3 mg·g-1,which was over 8 times higher compared to the limited 34.0 mg·g-1 over the activate carbon.Furthermore,the carbon was found to be an efficient adsorbent towards a series of metal ions including VO2+,Cr3+,Ni2+,Cu2+and Cd2+.Combined with its environmental merits,the protein derived carbon may be a promising candidate for heavy metal pollution control.

Urban Wastewater Characteristic and its Management in Urban Areas—A Case Study of Mysore City, Karnataka, India

The rapid growth of the population, the technological and industrial boom has brought enormous prob-lems and degradation of the environment. There is a gradual decline in availability of fresh water to be used for irrigation in India. As a consequence, the use of urban waste water (UWW) for irrigating agricultural lands is on the rise particularly in peri-urban areas of developing countries. Effective collection and treatment of urban wastewater is a critical problem in a developing country like India. A case study was undertaken to assess the characteristic of the urban waste water and its management in Mysore city and its long-term effect on irrigation. The untreated and treated urban waste water was collected during 2008 and analyzed in the laboratory. The suitability of the UWW for irrigation purposes is then evaluated according to the existing water quality standards and the results were compared with Food and Agriculture organization (FAO) irrigation water quality standards. It is evident from the results, that the current situation is not promising especially regarding the Electrical Conductivity, Total Dissolved Solids, Biochemical Oxygen Demand, Chemical Oxygen Demand, Suspended Solids and heavy metal concentrations and also pH of the treated UWW is exceeding the FAO standards. Among the heavy metals, the concentration of Iron and chromium are exceeding the FAO standards.

Impact of <i>Moringa oleifera</i>Cake Residue Application on Waste Water Treatment: A Case Study

Most of water treatments require higher expenditure. Chemical coagulant requires higher cost and has some drawback after treatment such as pH changes. Moringa oleifera cake residue (MOCR) is one of the alternatives to replace chemical coagulant. A jar test apparatus was used to monitor water treatment. Water quality of Gebeng River (GR) and waste water (WW) was examined before and after treatment. Different parameters using (MOCR) was investigated. Preliminary laboratory results showed the great potential of the (MOCR) to be used in water treatment. MOCR shows an excellent reduction in turbidity (97 % was removed). The bacteria were reduced from 1.7 × 105 to 8 × 103 CFU/ml. Dissolved oxygen (DO) was improved that elevated from 1.06 ± 0.04 to 5.09 ± 0.03 mg/L. However, chemical oxygen demand (COD) and biological oxygen demand (BOD) were increased from 520.5 ± 0.71 to 865.0 ± 2.12 mg/L and from 120.5 ± 2.12 to 270.5 ± 2.12 mg/L respectively. Nevertheless, there is no significant alteration of pH, conductivity, salinity and total dissolved solid (TDS) after treatment. The iron (Fe) was fully removed while copper (Cu) and cadmium (Cd) were successfully removed up to 98%. The reduction of lead (Pb) also achieved 82.17%. Also, (MOCR) can be stored for long time up to 6 months without affecting the biological properties of MO.

Assessment of Pollutants in Wet and Dry Depositions in a Suburban Area around a Waste-to-Energy Plant (WEP) in Northern Italy

Atmospheric concentrations of many trace elements are significantly affected by human activities, and their quantification in atmospheric deposition can be useful to ascribe to different sources of pollution. An important source of pollution, which creates concern in the inhabitants of neighboring areas, are waste-to-energy-plants, that nonetheless are necessary in the actual management of municipal solid waste. For this reason the waste-to-energy (WEP) plant of Bologna (Italy) was monitored from 2006 to 2008, collecting rainfall water in 6 sites around it. Moreover, dry deposition of pollutants was determined after leaching from leaves, with four samples collected during 2007. Trace elements were analyzed using spectrometry, deposition and fluxes were calculated. Results show that there is a large variability of concentrations of trace elements both in time and space. Moreover, the pollution in the area is quite diffused, with no clear determination of the role of the WEP. As a general remark, elements and trace elements found both in rainfall water and in leaching water from leaves showed a diffused pollution in all the monitored sites, probably due to the WEP but also to industrial/commercial area, large constructions and high traffic roads. In any case the values found in the area are comparable to values detected in similar area all over the world.

Impact Assessment of Poultry Discharge on the Physico-Chemical and Microbiological Water Quality of Olosuru Stream in Ikire, Southwestern Nigeria

This study investigated the impact assessment of poultry wastes discharge from a nearby poultry farm on the physico-chemical and microbiological water quality of Olosuru Stream, Ikire, Southwestern Nigeria. Five sampling stations (designated A, B, C, D and E) each located at 250 m interval along the course of the stream were selected for the study. The physico-chemical parameters in the water body vary in concentration along spatial, monthly and seasonal variation of Olosuru stream. The patterns of spatial distribution of physico-chemical parameters measured for the stream were generally similar except for calcium and hardness which showed significant difference for the five stations. The overall mean values of most of the parameters investigated;pH (7.45 ± 0.24), conductivity (628.69 ± 255.95 μs/cm), TDS (377.3 ± 153.55 mg/L), sulphate (10.89 ± 2.37 mg/L), BOD5 (3.19 ± 2.35 mg/L), cadmium, arsenic, manganese, total heterotrophic bacteria count (15,080.67 ± 20,250.67 cfu/ml), total coliform bacteria count (3226 ± 8426.70 cfu/ml) and total heterotrophic fungi count (2567.4 ± 7652.12 cfu/ml) were negatively impacted by poultry wastes dumping into the stream. The concentrations of most parameters exceeded recommended permissible limits of the Nigerian Standard for Drinking Water and World Health Organization for freshwater quality. The water source is therefore deemed not potable and poses hazards to public health if consumed without treatment. There is urgent need for improved management strategies of this water resource for continued sustainability.

Impact and Health Risk Assessment of Groundwater in the Vicinity of Dumpsites in Keffi Metropolis, Nigeria

This study investigated the hydrogeochemical characteristics of groundwater impacted by waste dumps through computation of different hydrogeological/chemical indices and related health risk assessment of major heavy metals (HVM) in relation to different population groups in Keffi Metropolis. Samples from ten (10) groundwater sources were collected for analysis. Results revealed that the concentration of major cations from the samples was in the order: Ca2+ > Na+ + K+ > Mg2+, while major anionic constituents were in the order: HCO3- > CO32- > SO42- > Cl- > F- respectively. Water quality index (WQI) computed indicated that the groundwater of the study area is not suitable for domestic purposes particularly drinking as some of the parameters exceed the WHO guidelines. Generally, the HVM hazard quotients (HQ) of non-carcinogenic (NC) and carcinogenic toxicity (TC) for both population groups were lower (HQ < 1) indicating that the groundwater within the study areas did not pose current significant risk. Non-carcinogenic risk uncertainty analysis by Monte Carlo simulations (MCS) further indicated that risk levels of HVM in GW were lower (HQ < 1). Despite the findings in this study, it is important that regular monitoring of GW quality is done in order to ensure that water is potable and prevent human health risks.

脉冲电晕放电等离子体-活性炭协同去除废水中重金属离子和有机物

为了同时去除废水中的重金属离子和有机污染物,以镉离子(Cd2+)和酸性橙7(AO7)为目标污染物,研究比较了活性炭(AC)、脉冲电晕放电等离子体(PCDP)以及PCDP结合AC(PCDP-AC)3种体系对废水中Cd2+和AO7的去除效果。考察了脉冲放电电压、载气种类、溶液初始pH值和电导率对Cd2+和AO7去除的影响。结果表明:PCDP-AC体系可以同时有效地去除废水中的Cd2+和AO7,且去除效果明显好于AC和PCDP单独处理;增加脉冲放电电压,可以提高Cd2+和AO7去除率;氧气作为载气的去除效果高于空气或氮气作为载气的去除效果;酸性条件下AO7的去除率好于碱性条件,而Cd2+的去除率在碱性条件下好于酸性条件;增加溶液初始电导率,会导致Cd2+和AO7去除率下降。

化学沉淀-铁氧体法处理重金属废水试验研究

重金属离子排放到环境中只能改变形态或被转移、稀释、积累,对生物危害很大。为了处理含多种重金属离子的废水,本试验采用化学沉淀-铁氧体法处理主要含铅、锌、镉离子的废水。以云南弛宏锌锗股份有限公司废水为原水,在对影响处理效果的各种要素如温度、pH值、搅拌时间进行了条件试验后,得出了去除重金属离子废水静态试验的最佳条件。

微波改性膨润土吸附-PAM混凝联用技术处理冶炼废水中的重金属

采用微波对膨润土进行改性,研究微波改性膨润土吸附与聚丙烯酰胺(PAM)混凝联用技术处理实际冶炼废水中的重金属。结果表明,单独微波改性膨润土吸附试验中,当投加量为25 g/L,废水中的锰、锌、镉和铅的去除率分别可达71.9%、89.7%、78.5%和93.1%;采用微波改性膨润土吸附与PAM混凝联用技术时,重金属的去除率均有上升,沉降效果明显改善。当微波改性膨润土投加量为25 g/L,PAM投加量为2 mg/L,吸附时间为50 min,废水pH=8时,对锰、锌、镉和铅的去除率分别可达98.9%、99.6%、99.7%和98.3%,出水中的锌、镉和铅的排放浓度可达到国家相关水质标准。

固定化Ralstonia metallidurans CH34在三相流化床中降解苯酚的研究

通过探索固定化细菌Ralstonia metallidurans CH34在三相流化反应器中降解苯酚的反应条件,对固定化细胞处理工业废水进行模拟研究,以期提高R.metallidurans CH34降解苯酚的能力和效率。结果表明,固定化R.metallidurans CH34在三相流化反应器中明显提高了降解苯酚的能力,耐抗金属性也有较大的提高,而且能够在模拟工业废水中批次培养3-4次,其降酚能力退化并不明显。这为R.metallidurans CH34实际应用提供了可靠的基础。

乙二胺四乙酸根插层镁-铝水滑石的制备与性能

通过共沉淀法合成乙二胺四乙酸根(EDTA^(4-))插层的镁-铝水滑石(MgAl-EDTA-LDH),并采用X射线衍射和红外光谱对其结构和化学组成进行表征,研究MgAl-EDTA-LDH对水溶液中铜离子的去除能力。结果表明,乙二胺四乙酸根已插入镁-铝水滑石的层间,且插层水滑石能有效吸附水溶液中的铜离子,在2 h时吸附效率可达93.05%。

M(Ⅱ)-S-H_2O体系的热力学平衡

根据配位化学热力学平衡原理,绘制了298.15 K时S-H2O系含硫物种的离子分率αn-pH图,以及4种重金属离子(Cu、Pb、Zn、Cd)-S-H2O体系的硫化平衡pM-pH图.αn-pH图指出了不同pH值下水溶液中硫的存在形式,当pH>12.5时,溶液中逐渐出现S2-,pH值达到16以上时,溶液中的S主要以S2-的形式存在,其离子分率达到了98.61%.pM-pH图指出了4种重金属硫化物在溶解平衡时,总离子浓度与pH值的关系.pH值分别在7.75、8.87、8.36、9.83时,CuS、PbS、ZnS、CdS的溶解度最小.同时对热力学计算结果进行了实验验证,结果表明:在一定的金属浓度下,pH值分别为8.2、8.7、8.3、10.3时,溶液中金属离子浓度达到最小值,基本符合热力学分析结果.这些热力学研究具有较高的实用价值,为硫化沉淀法处理重金属废水提供了理论依据.

铬离子捕集剂Cr-BD的应用研究

本文根据铬鞣废水的特征及处理要求,提出了一种铬鞣废液的处理与循环利用新方法。介绍了使用大分子配位体铬离子捕集剂Cr-BD技术关键。

固体废物中的重金属对土壤及地下水的污染分析

随着社会经济的发展,工业生产规模的扩大,在工业生产过程中会产生大量固体废物,对生态环境造成严重污染。固体废物中含有大量重金属物质,此类物质会严重污染土壤及地下水资源,影响人们的身体健康。目前,我国土壤及地下水受到固体废物中重金属的严重污染,对社会发展、生态环境和人民生产生活构成了威胁。因此,我们应采取相关措施加以解决。本文简要阐述了固体废物中重金属的来源及影响,并重点研究了解决措施,以供参考。

铜冶炼污酸废水泄漏重金属Zn、As对地下水的影响

铜冶炼过程产生的污酸废水中重金属Zn、As浓度较高,发生泄漏会下渗到区域地下水环境,对地下水环境产生不利影响。选择一维对流扩散模型对铜冶炼污酸废水事故状态下入渗地下水环境情境进行预测,污染物随地下水往下游迁移,特征污染物As、Zn的污染前锋迁移500 m的距离分别需要609、751 d;迁移2 300 m的距离分别需要6 292、7 086 d,该预测结论可为同类企业地下水的防治提供借鉴依据。

可视移动中和反应界面离线富集-毛细管电泳法检测电镀废水中痕量重金属离子

建立了一种可视化的、利用移动中和界面离线富集-毛细管电泳检测电镀水中痕量重金属离子的新方法。在该富集系统中,阳极电解液为2.1 mmol/L HCl-98 mmol/L KCl-痕量重金属离子,阴极电解液为4.0 mmol/LNaOH-96mmol/L KCl,界面向阴极移动,分离电压为180V,阴极电解液和阳极电解液的流速均为1mL/min。富集后凝胶中的金属离子浓度用毛细管电泳检测,标准曲线在实验浓度范围内均有良好的线性关系(r≥0.998 5),预富集倍数达80～150倍,Cu(Ⅱ)、Zn(Ⅱ)、Ni(Ⅱ)、Mg(Ⅱ)、Ca(Ⅱ)、Cr(Ⅲ)和Fe(Ⅲ)的检出限分别为0.163、0.256、0.077、0.153、0.203、0.062和0.142mg/L,均明显低于国家规定标准;日内和日间精密度均小于7.42%。所建方法已成功用于实际电镀废水样品中痕量重金属离子的富集和检测。

中和-电絮凝法脱除废水中重金属的研究

对中和法与电絮凝法相结合的工艺脱除废水中的重金属进行了研究。先采用中和法预处理原废水中的氨氮,氨氮含量降至7.8 mg/L,Pb、Fe、Zn完全脱除。再采用电絮凝法脱除残余重金属,考察了反应时间、电流强度、极板间距对重金属脱除效果的影响。结果表明:经中和-电絮凝法处理后的废液达到国家地表水环境质量Ⅲ类标准。

微生物燃料电池双向处理焦化-重金属废水性能研究

分别采用焦化废水和4种不同重金属废水作为阳极底物和阴极液,构建双室微生物燃料电池(MFC),考察其同步处理2种废水的产电性能及污染物处理效果。运行数据表明:以不同重金属离子(Cu^(2+),Cr^(2+),Cd^(2+)和Ni^(2+))废水作为阴极液的MFC装置的运行性能差别较大。以Cr^(2+)作为MFC装置阴极液时,系统运行性能最高,输出电压、功率密度、库伦效率、COD去除率及金属离子去除率分别为(455±12)m V,36.2 m W/m^(3),45.1%,(85.2±1.6)%和(68.9±1.8)%。

ICP-AES法测定工业废水中Cu、Pb、Zn、Cd、Cr、As和Hg

本文研究了ICP-AES法测定冶炼工业废水中Cu、Pb、Zn、Cd、Cr、As和Hg条件。方法操作简便,分析速度快,结果准确。