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 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.

暴雨作用下新型透水混凝土的净水性能

针对透水混凝土因强度与耐久性不足等原因而局限于轻型交通等级路面使用的问题,制备出一种以C80自密实混凝土为基体的新型直通孔高强透水混凝土,探讨了不同暴雨强度等级作用下新型透水混凝土对重金属离子的净化能力,研究了混凝土各组分对Cu^(2+)、 Zn^(2+)的净化效果,并分析其去除机理。结果表明:该透水混凝土具有优异的力学性能(抗压强度94.8 MPa,抗折强度8.4 MPa)和透水性能(透水系数0.81 mm/s),随着暴雨作用等级的增大,透水混凝土对Cu^(2+)、 Zn^(2+)的去除率逐渐减小(在特大暴雨作用下最大去除率仍能达到22.5%和17.5%),具备良好的净水能力。组分净水试验结果表明:胶凝材料的水化产物是重金属离子的主要吸附剂,粉状水化胶凝材料对Zn^(2+)的去除效果优于Cu^(2+),块状水化胶凝材料和钢纤维则对Cu^(2+)的去除效果更明显。

光催化技术在水处理中的应用研究进展

光催化技术应用于水处理领域,既可以提高水质安全,也可以缓解全球水资源短缺问题,是一项具有广泛应用前景的技术。该文介绍了光催化技术的机理及常见光催化剂的特点,重点综述了光催化技术在饮用水中的除臭、消毒,在染料废水含油废水制药废水催化还原重金属离子养殖废水焦化废水方面的应用。自由基途径与非自由基途径在该技术中发挥重要作用,在光催化材料中,TiO_(2)､金属-有机框架(MOFs)基光催化材料及其类似材料(如MIL系列､ZIFs系列等)可产生更多的•OH;TiO_(2)､g-C_(3)N_(4)基光催化材料可产生更多的•O_(2)^(–)和e^(–);CdS､TiO_(2)､g-C_(3)N_(4)基光催化材料可产生更多的h^(+)。最后对光催化技术的机理､光催化材料、水处理方向及实际应用进行了总结与展望。

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。

酸性矿山废水中多种有价金属的高效分离

酸性矿山废水(AMD)中多种有价金属的高效分离回收,是重金属减排和资源化利用的关键。文章通过中和沉淀实验和静态吸附实验探究回收有价金属的最佳沉淀和吸附pH,成功开发了中和沉淀—离子交换—中和沉淀组合工艺,并应用于大宝山AMD的处理。结果表明,AMD在pH为3.00和9.80中和沉淀时,分别沉获64%的Fe_(2)O_(3)富铁渣和51%的Mn O富锰渣。采用离子交换树脂分别在pH 3.95和6.10条件下对AMD中的Cu和Zn进行吸附,得到质量浓度为Cu^(2+)11~26 g/L,Zn^(2+)10~20 g/L的两种解吸液。通过该组合工艺,AMD中的各金属Fe、Cu、Zn和Mn的回收率分别为:96%、81%、70%和60%,实现了有价金属的高效分离回收。若采用此工艺回收大宝山2000 m^(3)/d的AMD中的铜、锌、锰硫酸盐,每年的利润为119万元,经济效益非常显著。此处理工艺为酸性矿山废水的高效资源化利用提供了新路径。

生物阴极MFC处理重金属废水研究进展

生物阴极微生物燃料电池(MFC)可以将重金属废水中的有害重金属阳离子还原成单质或低毒低价态物质,此法具有高效、低毒无污染等优点,有望为重金属污染废水的生物修复提供一种新途径。介绍了微生物燃料电池,概述了生物阴极上电化学过程与微生物在还原重金属离子过程中所发挥的协同作用,探讨了近期生物阴极微生物燃料电池的研究趋势,对今后强化生物阴极微生物燃料电池重金属废水处理效率及实际应用进行了展望。

金属有机框架材料对水体中重金属离子去除性能及机理的研究进展

工业化进程的加快导致全球环境污染日趋严峻,尤其是铬、砷、铅、汞、镉、锌、铜及镍等重金属污染极为显著。重金属在水体中多以离子态存在,难以生物降解,将对生态环境和人类健康构成巨大威胁,因此寻求经济、高效的重金属去除方法刻不容缓。水体中重金属去除的方法主要包括离子交换、混凝沉淀、氧化还原、吸附、膜过滤及电渗析等,其中吸附法具有成本低廉、操作简单和适应性强等诸多优点,被认为是去除水体中重金属的优选方法之一。金属有机框架材料(MOFs),因其比表面积大、孔隙率高、活性位点丰富、可调节性强及热/化学稳定性高等特性,被广泛应用于去除水体中的重金属。重点综述了MOFs及其复合材料对铬、砷、铅、汞、镉、锌、铜及镍重金属离子的去除性能,分析了MOFs初始浓度、重金属离子浓度、接触时间、pH值、温度及干扰离子等因素对重金属去除效果的影响。同时,明确了MOFs去除重金属离子的机理。其主要作用机理为吸附、沉淀及氧化还原,其中吸附分为物理吸附和化学吸附,物理吸附主要包括静电引力、扩散作用和范德华力,化学吸附主要包括开放金属位点/配位作用、酸碱作用及氢键作用,而沉淀或者氧化还原伴随在吸附过程中。此外,对今后MOFs材料在重金属污染防治领域的研究方向及潜在应用进行了展望,以期为MOFs材料在环境污染修复领域的研究和应用提供理论基础。

离子色谱技术在水环境检测中的应用思考

随着工业化和城市化进程的加快,水污染问题日益严峻,对人类健康和生态环境构成了巨大威胁,所以需要对水环境进行监测。离子色谱技术作为一种高效、灵敏的分析方法,在水环境质量监测中显示出不可替代的作用。本文综合探讨了离子色谱技术的基本原理,并深入分析了其在水环境检测中的广泛应用,如常规阴阳离子、有机污染物、重金属的检测等。同时,文章也详细讨论了离子色谱技术的优势。离子色谱技术在实际应用中也存在着一些挑战和问题,例如高昂的设备与耗材成本、部分离子的检测效果不理想以及样品前处理步骤的复杂性等。针对这些问题,本研究提出了一系列改进措施,旨在进一步提升离子色谱技术在水环境监测中的效能和准确性。

富咪唑型多孔左旋聚乳酸纳米纤维膜制备及其双重净水性能

为开发具有油水分离和吸附重金属离子双重功能的新型膜材料,利用静电纺丝技术制备左旋聚乳酸(PLLA)纳米纤维膜,再依次采用溶剂诱导结晶和1-(3-氨基丙基)咪唑(API)修饰改性得到富咪唑型多孔PLLA纳米纤维膜,并对其微观形貌、化学基团构成、力学性能和润湿性能进行测试与表征,研究了该纳米纤维膜的油水分离性能和对铜离子的吸附性能。结果表明:当丙酮与水体积比为10∶1、丙酮/水混合溶液用量为0.4 mL/(mg纤维)、处理时间为150 s时,溶剂诱导结晶处理所得PLLA纳米纤维膜中多孔纤维的形貌最佳;API修饰改性并未对多孔纤维的形貌和直径产生过多影响,改性后PLLA纳米纤维膜表面出现的咪唑和酰胺基团能够有效改善其润湿性能,使静态水接触角下降了15.6°;与未改性PLLA纳米纤维膜相比,所制得富咪唑型多孔PLLA纳米纤维膜的脆性有所增加,但其断裂强度仍能达到未改性的PLLA纳米纤维膜断裂强度的96.6%,整体力学性能保持良好;利用该纳米纤维膜可实现有效油水分离,分离通量为1044.9 L/(m^(2)·h),分离效率可达99.1%,且其对铜离子吸附性能良好,在pH值为6的铜离子溶液中接触24 h后,对铜离子吸附量可达41.46 mg/g。

表面处理废液资源化利用技术的研究进展

金属表面处理工艺常使用强酸溶液(例如:硝酸、盐酸等)去除金属工件表面的氧化物,以提高电镀层的强度和金属工件的耐腐蚀能力,因此表面处理废液中含有大量的金属离子和废酸。沉淀法、蒸发法和离子交换法等技术通过沉淀金属离子、分离酸液、提高母液中金属离子浓度等途径实现表面处理废酸液的资源化利用。各类表面处理废酸液资源化利用手段的机理不同,沉淀法利用羟基中和反应和金属硫化物沉淀等原理实现金属离子与废酸液的分离;蒸发法利用部分酸液易挥发和金属盐溶解度不同等特性实现酸液和金属离子的资源化利用;离子交换树脂通过选择性吸附-洗脱这一过程实现目标离子的回收再利用;渗析法是利用膜的选择透过性或电场力实现酸和金属盐的分离。利用工业余热、增加预处理工艺、耦合其他工艺、降低二次污染物产出以降低表面处理废酸液资源化利用成本、提高资源化利用效率是未来该领域的研究重点。

电化学检测水体重金属离子分析方法研究进展

重金属离子是水体污染的主要来源之一,其难降解、易富集等特性可导致生物体的慢性甚至急性中毒,对水环境的生态平衡和人类健康构成严重威胁。随着对水体重金属离子检测需求的不断增加,电化学检测方法因其速度快、灵敏度高、操作方便、成本低的特点受到更多的青睐。然而,在实际检测过程中,由于环境和检测方法本身的干扰,致使检测结果的准确性不够理想,因此需要通过算法及恰当的解析方法对检测数据进行校正和分析。本文从背景电流的处理、分类识别技术和回归预测模型三个方面介绍检测数据分析和处理的方法,并对该领域的发展进行了展望。

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。

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.