Sound management of brominated flame retarded (BFR) plastics from electronic wastes: State of the art and options in Nigeria

Management of flame retarded plastics from waste electrical and electronic equipment (WEEE) has been posing a major challenge to waste management experts because of the potential environmental contamination issues especially the formation of polybrominated-dioxins and -furans (PBDD/F) during processing. In Nigeria, large quantities of electronic waste (e-waste) are currently being managed—a significant quantity of which is imported illegally as secondhand electronics. As much as 75% of these illegal imports are never reused but are rather discarded. These waste electronic devices are mostly older equipment that contains brominated flame retardants (BFRs) such as penta-brominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) which are presently banned in Europe under the EU WEEE and RoHS Directives. Risk assessment studies found both to be persistent, bio-accumulative and toxic. The present management practices for waste plastics from WEEE in Nigeria, such as open burning and disposal at open dumps, creates potential for serious environmental pollution. This paper reviews the options in the environmentally sound management of waste plastics from electronic wastes. Options available include mechanical recycling, reprocessing into chemicals (chemical feedstock recycling) and energy recovery. The Creasolv^® and Centrevap^® processes, which are the outcome of the extensive research at achieving sound management of waste plastics from WEEE in Europe, are also reviewed. These are solvent-based methods of removing BFRs and they presently offer the best commercial and environmental option in the sound management of waste BFR-containing plastics. Because these developments have not been commercialized, WEEE and WEEE plastics are still being exported to developing countries. The industrial application of these processes and the development of eco-friendlier alternative flame retardants will help assure sound management of WEEE plastics.     

Quality assessment of composts in the Greek market: the need for standards and quality assurance

An extensive data survey and study of the Greek market for composts or products marketed as such was carried out in order to acquire a comprehensive image of the local situation, in view of the proposed operation of large municipal solid waste (MSW) composting facilities and EU legislation changes. Physical and chemical parameters (moisture, organic matter, electrical conductivity, pH and heavy metals), stability indicators (self-heating potential, germination index) and biological indicators (microbial population, pathogen indicators and selected pathogens) were analyzed for the assessment of product quality. Results revealed wide variations even within the same group of products, which is particularly significant for parameters directly related to environmental protection and public health. The heavy metal content ranged from levels exceeding the fairly lenient Greek standards to below the stringent limits for A+ class compost in Austria. About 25% of the composts examined met the heavy metal limits for the EU eco-label award. Salmonella spp. was not detected in any of the composts but Staphylococcus aureus and Clostridium perfringens were found in 17 and 96% of the composts respectively. Pathogen indicator microorganisms were present at levels above suggested limits in all the composts. The high variability of such important parameters in composts available on the Greek market suggests an urgent need for establishing quality assurance procedures and mechanisms in the country. Moreover, the wide range of limit values within EU member states suggests the need for developing EU compost quality standards, in order to harmonize the compost markets.     

Present status of the recycling of waste electrical and electronic equipment in Korea

In Korea due to rapid economical growth followed by urbanisation, breakage of large traditional families into small nuclear families, continuous changes in equipment features and capabilities causes tremendous increase in sale of new electrical and electronic equipment (EEE) and decrease in sale of used EEE. Subsequently, the ever-increasing quantity of waste electrical and electronic equipment (WEEE) has become a serious social problem and threat to the environment. Therefore, the gradual increase in the generation of WEEE intensifies the interest for recycling to conserve the resources and protect the environment. In view of the above, a review has been made related to the present status of the recycling of waste electrical and electronic equipment in Korea. This paper describes the present status of generation and recycling of waste electrical and electronic equipment, namely TVs, refrigerators, washing machines, air conditioners, personal computers and mobile phones in Korea. The commercial processes and the status of developing new technologies for the recycling of metallic values from waste printed circuit boards (PCBs) is also described briefly. Since 1998, three recycling centers are in full operation to recycle WEEE such as refrigerators, washing machines and air conditioners, having the total capacity of 880,000 units/year. All waste TVs are recently recycled on commission basis by several private recycling plants. The recycling of waste personal computers and mobile phones is insignificant in comparison with the amount of estimated obsolete those. Korea has adopted and enforced the extended producer responsibility (EPR) system. Korea is making consistent efforts to improve the recycling rate to the standards indicated in the EU directives for WEEE. Especially environmentally friendly and energy-saving technologies are being developed to recycle metal values from PCBs of WEEE.     

University of Benin water supply system: Microbiological and physico-chemical assessments

The microbiological and physico-chemical characteristics of the drinking water supplied by the Central Borehole at the University of Benin, Ugbowo Campus were investigated. The investigation entailed assessment of the pH, turbidity, total suspended solids, total dissolved solids, dissolved oxygen, temperature, salinity, conductivity, nitrate, nitrite, phosphate, sulphate, chloride, N-nitroso compounds, cadmium, chromium, nickel, lead, zinc, manganese, iron, coliform count, BOD₅ and COD of the water at the Central Borehole and at ten residential quarters. The assessment indicated that the water was fit for drinking and other domestic applications. Results were also compared with WHO, EU and Nigeria FEPA standards. The results showed that the pH values of the water (5.01–5.86) and total coliform count (1–2/100 ml) expressed as MPN were outside the limits set by the WHO, EU and FEPA. The data also showed that the other water quality parameters assessed were within WHO, EU and FEPA permissible limits. The results of ANOVA showed that significant changes occurred during distribution.     

Closed loop recycling of plastics containing Flame Retardants

Annually 2.7 million tonnes of plastics containing Flame Retardants (FRs) are globally discarded in Waste Electrical and Electronic Equipment (WEEE). Little is known on the feasibility of closing material loops for FR plastics. Therefore, series of experiments were set up to analyze the feasibility of separating plastics containing FRs from one specific product category, namely End-of-Life (EoL) Liquid Crystal Display (LCD) TVs. The characterization of the housings of this waste stream indicated a concentration of 18 wt% Bromine based (Br) FRs and 31 wt% Phosphor based (P) FRs, the remainder not containing FRs. With practical tests it was demonstrated that, after disassembly and plastic identification, the co-polymer poly-carbonate (PC)/acrylonitrile-butadiene-styrene (ABS) containing PFR can be recycled in a closed loop system. Based on the determined plastic density distributions and separation efficiencies of optical sorters, a purity of 82% was calculated for PFR PC/ABS separated from EoL LCD TVs after size-reduction (shredding). Performed miscibility tests indicated that for this fraction at least a factor 10 dilution with virgin material is required. In addition, higher waste volumes are required for a size-reduction based treatment to become economically viable and technical challenges still need to be faced, whereas closed loop recycling of PFR PC/ABS from the current waste stream of EoL LCD TVs of different brands in a disassembly based treatment is found to be technically feasible and economically viable under European boundary conditions.     

阿尔金山保护区地表水部分重金属背景值调查与分析

根据实地考察,采集了阿尔金山保护区主要地表水体的水质样本。受考察期限和水质样本保存要求与期限限制,只对样本中铜、锌、镉等重金属指标进行了检测,分析了各指标与《地表水环境质量标准》中不同标准限值的关系,及其在地理空间上的分布规律。本次考察分析的结果可作为后期水质考察的背景信息,是进一步开展保护区水环境调查和研究的基础。     

Development and use of site-specific chemical and biological criteria for assessing New Bedford Harbor pilot dredging project

Numerical site-specific chemical and biological criteria were established to assess the impact of a pilot dredging project on water quality at the New Bedford Harbor, Massachusetts, USA, Superfund site. Because most existing chemical concentrations in the water column and indigenous biota exceeded federal and state water quality limits, the derivation of site-specific criteria was required. Prior to any operational phases of the project (i.e., dike construction, dredging), criteria values were developed from background concentrations of PCBs and metals in water and biota, as well as for the toxic effects of water quality on the biota. During each operational phase of the project, water samples were collected, analyzed within 16 h, and the data supplied to a management committee in order to assess the environmental impact of the previous days' operation. The ambient unfiltered water concentration of PCBs and metals were the only chemical or biological criteria exceeded. Modification of the next days' operations resulted in a return of these concentrations to background levels. The combined use of site-specific criteria and a real-time decision making management process allowed for successful completion of this project with a minimal effect on water quality.     

Implementation of Waste Electrical and Electronic Equipment Directive in Finland: Evaluation of the collection network and challenges of the effective WEEE management

Further to the European Waste Electrical and Electronic Equipment (WEEE) Directive, setting up efficient collection schemes is necessary to ensure the recovery targets set. Following the subsidiary principle, the WEEE Directive defines only the general requirements for mandatory collection and recycling objectives. The modalities of the logistics and the organisation of the take-back schemes are left to the choice of Member States. In this paper, the implementation of the WEEE Directive and the development of the WEEE recovery infrastructure in Finland are described and the challenges to the effective management of the WEEE recovery system in Finland are expressed. It can be said that the implementation of the WEEE Directive has succeeded in Finland and, at the same time, the legislative basis has been enacted. In addition, a functional WEEE recovery infrastructure has been built and, the collection requirements of the WEEE Directive have been exceeded in a relatively short time. However, the paper outlines that some inefficient practices still exist, particularly in the registration and WEEE collection stages. It is concluded that raising awareness would lead to a more environmentally sound behaviour and would, ultimately, improve WEEE recovery efficiency.     

欧盟废物焚烧指令的研究与借鉴

为进一步完善我国废物焚烧标准体系,防控废物焚烧环境风险,本文对欧盟废物焚烧指令与我国焚烧标准体系进行了对比分析。欧盟废物焚烧指令分别对专用焚烧厂和协同焚烧厂从废物运输到处理处置全过程的污染物排放控制做出了相关规定,适用于危险废物和非危险废物的焚烧以及常规污染物和有毒污染物的控制。欧盟废物焚烧指令对不同规模的焚烧设施采用统一标准,以日均值和半小时均值为污染物排放限值,更客观、准确地评价了污染物排放对环境的影响。与欧盟废物焚烧指令相比,我国废物焚烧标准涉及废物联合利用处置的相关条文较少,内容不详,项目缺失。我国烟尘、HCl的排放限值均在欧盟标准限值6倍以上,SO2的排放限值是欧盟标准的4~8倍。除CO、NOx的排放限值外,其他污染物排放限值也明显高于欧盟标准限值。我国采用抽样监测方法,监测结果可能在日常排放值的95%置信区间外,不具备代表性。我国可借鉴欧盟废物焚烧指令的成果制定协同焚烧标准,并严格污染物排放限值,考虑采用日均值或半小时均值的评价方法,提高我国废物焚烧标准的精确性和可执行性。     

Physical and chemical characterisation of metal finishing industrial wastes

In EU countries approximately 150,000 tons/year of galvanic sludges are generated by 4000 industrial units from the corresponding wastewater treatment plants. These sludges are generally classified as hazardous (European Waste Catalogue as adopted in Council Decision 2000/532/CE and as amended by Decisions 2001/118/EC, 2001/119/EC and 2001/573/CE), basically due to the presence of heavy metals. This work attempts to better understand the physical and chemical characteristics of these sludges, by studying 39 samples collected in different Portuguese industries that should represent all kinds of similar wastes independent of their place of generation. Chemical composition and leaching characteristics are given, together with density, grain size distribution, and specific surface area values. Statistical analysis was used for grouping the wastes according to chemical parameters, which might be useful to predict potential reuse as raw materials for different applications.     

Assessment of Presence of Heavy Metals and Other Pollution Burden Parameters and Their Effect on Water Quality in Benin City,Edo State

An assessment of the heavy metal content and biological pollution burden of an abattoir dumpsite, an automobile carwash, the Ikpoba River, and a private water borehole located near the abattoir dumpsite was conducted in Benin City in Southern Nigeria, during the rainy and dry seasons. The water samples’ pH was lower than the permissible values, with the river water displaying color and possessing a slight odor. Iron concentrations exceeded the permissible limits for drinking water at all four of the sampling stations in the study area, although not in samples collected from the control station, station 5, a public water borehole that is located some distance away. Lead values were higher than drinking water standards in the samples collected from stations 1 through 4, with some exceptions during the rainy season. Copper, nickel, arsenic, chromium, and aluminum were detected in three out of the four sampling stations located within the study area. However, these metals were detected at levels that were within regulatory limits. The detection of three metals (iron, lead, and zinc) within the study area at levels exceeding drinking water limits suggested that a complete cycle of movement of pollutants into the sampling stations had occurred. Significant biological presences were also detected, as the Ikpoba River water had a standard plate count (SPC) of 130 most probable number (MPN) and a 22 MPN presumptive coliform count (PCC) or 22 MPN. However, Escherichia coli (E. coli) confirmatory tests recorded less than 2 MPN in both seasons. The study has shown that the quality of water in the river may be compromised by effluent discharges from the dumpsite and the carwash channel. Therefore, this situation requires more stringent enforcement of local environmental laws and maintenance of safe distances between domestic and industrial waste sources and domestic or private water wells.     

Formulation of criteria for pollution control on cement products produced from solid wastes in China

The process of producing cement products from solid waste can increase the level of pollutants in the cement products. Therefore, it is very important to establish a pollution control standard for cement products to protect the environment and human health. This paper presents acceptance limits for the availability of heavy metals in cement products which have been produced from solid wastes and explains how the limits have been calculated. The approach and method used to formulate these criteria were based on EN 12920. The typical exposure scenarios used in this paper involve concrete being used for drinking water supply pipelines and concrete pavements and are based on an analysis of typical applications of cement in China, and the potential for contact with water. The parameters of a tank test which was based on NEN 7375 were set in accordance with the environmental conditions of typical scenarios in China. Mechanisms controlling the release of heavy metals in concrete and a model for that release were obtained using the leaching test. Finally, based on acceptance criteria for drinking water and groundwater quality in China, limit values for the availability of heavy metals in concrete were calculated.     

废旧电子电气设备回收处理的研究进展

概述了目前全球对废旧电子电气设备(Waste of Electronic Electric Equipment,简称WEEE)回收处理的基本情况,并根据废旧电子电气设备处理的特点,从机械物理处理方法、热化学处理方法以及处理过程中产生有毒有害物质的分离技术三方面,介绍近年来废旧电子电气设备回收处理的研究进展,最后指出了真空热解的使用将作为未来废旧电子电气设备处理的发展方向。     

德国双元系统对电子废弃物回收的启示

本文回顾了德国双元系统在包装物回收领域取得的成功，探讨了此系统应用于电子废弃物回收的可行性与优势。针对电子废弃物的特性，本文提出了一系列相应的改进措施，使德国双元系统能够适用于电子废弃物的回收。     

Leaching characteristics of copper flotation waste before and after vitrification

Copper flotation waste from copper production using a pyrometallurgical process contains toxic metals such as Cu, Zn, Co and Pb. Because of the presence of trace amounts of these highly toxic metals, copper flotation waste contributes to environmental pollution. In this study, the leaching characteristics of copper flotation waste from the Black Sea Copper Works in Samsun, Turkey have been investigated before and after vitrification. Samples obtained from the factory were subjected to toxicity tests such as the extraction procedure toxicity test (EP Tox), the toxicity characteristic leaching procedure (TCLP) and the "method A" extraction procedure of the American Society of Testing and Materials. The leaching tests showed that the content of some elements in the waste before vitrification exceed the regulatory limits and cannot be disposed of in the present form. Therefore, a stabilization or inertization treatment is necessary prior to disposal. Vitrification was found to stabilize heavy metals in the copper flotation waste successfully and leaching of these metals was largely reduced. Therefore, vitrification can be an acceptable method for disposal of copper flotation waste.     

Assessment of the degree of rancidity on reused oils in university cafeterias,and public awareness

In this study, reused sunflower cooking oil was investigated for rancidity. Three student cafeterias at the University of Dodoma (UDOM) were used for this particular study. Oil samples were analyzed at the University of Dodoma laboratories. Results showed that all parameters were beyond permissible limits by WHO/FAO standards. Acid values ranged between 0.841 and 4.319 mg KOH/g oil, which is beyond the allowable limits by WHO/FAO (0.6 mg KOH/g oil). Peroxide values were found to be 19.5 mill eq O₂/kg oil (minimum), and 62 mill eq O₂/kg oil (maximum), which are both above the recommended limits by WHO/FAO (10 mill eq O₂/kg oil). Iodine values were found to be from 102.87 to 48.26-g I₂/100 g oil, and were all beyond the recommended limits by WHO/FAO, of between 118- and 141-g I₂/100 g oil. The study has further revealed that the number of customers that are saved by the three cafeterias exceeds the capacity of the cafeterias. This study also found out that many students (almost 74%) are not aware on general knowledge about rancidity, including health effects of using rancid oils. It is therefore recommended to the national regulatory authorities to formulate strict regulations to guide and control oil rancidity.     

TOXIC EFFECTS OF PETROLEUM AND SHALE JP-4 AND JP-8 AVIATION FUELS ON FATHEAD MINNOWS1

ABSTRACT: Static 96-hour median lethal concentrations were determined for the water-soluble fraction (WSF) of both petroleum-derived and shale-derived avaiation fuels (JP-4 and JP-8) using fathead minnows. JP-8 was more toxic than JP-4 except for one shale JP-4 sample that was as toxic as the JP-8. Petroleum and shale JP-8 were similar in toxicity. The toxicity of shale JP-4 was less clear. Shale JP-4 from three vendor sources revealed differing toxicity values. One shale JP-4 sample was more toxic and one less toxic than its petroleum analogue, with the third being equally toxic. Toxicity of the fuels may be enhanced by compounds in the WSF that correspond to chemicals containing 10 or more carbon atoms.     

Thermal treatments of industrial wastes in controlled atmospheres for the elimination of As, Hg, Cd, Se and the concentration of Pb, Cu and Zn

Thermal treatments of five different types of non-ferrous metallurgical wastes, under a controlled atmosphere, were carried out at temperatures lower than 800°C for the separation of their toxic compounds and the concentration of valuable metals in the treatments residues. The best results were obtained by the treatments in air or hydrogen, or both successively. Simple treatments, using air or hydrogen, of three samples allowed the elimination of more than 95% of their toxic elements and almost doubled their valuable metals concentration. For the rest of the samples, a combined treatment was necessary for their efficient decontamination. In this case, the valuable metals content in the treatment's residue was increased to a reasonable value. Most of the solids issuing from these treatments can be recycled in current non-ferrous metallurgical processes.     

Biological responses in edible crab, <Emphasis Type="Italic">Callinectes amnicola</Emphasis> that could serve as markers of heavy metals pollution

Responses of lagoon crab, Callinectes amnicola were explored as useful biological markers of heavy metal pollution. The toxicity level of the metals based on the 96-h LC50 values showed that copper with LC50 value of 0.018 mM was found to be two times more toxic than Lead (0.041 mM) against the lagoon crab, C. amnicola. The exposure of the lagoon crab to sublethal concentrations (1/100th and 1/10th of 96-h LC50 values) of Cu and Pb compound, respectively, resulted in the bioaccumulation of the test metals to varying degrees in the selected organs that were dependent on the type of metal and concentration of metal compound in the test media. The degree of metal (Cu and Pb) accumulation was generally in the following order: gills > muscle > heptopancrease. Exposure of the crabs to sublethal concentrations of the metals also caused pathological changes such as the disruption of the gill filaments and degeneration of glandular cells with multifocal areas of calcification in the hepatopancreas. A reduction in the weight of the exposed animals over a 14-day period of observation was also recorded. The significance of these results and the usefulness of the biological endpoints in monitoring programmes aimed at establishing the total environmental level of heavy metals in aquatic ecosystems were discussed.     

Elemental contaminants in groundwater: A study of trace metals from residential area in the vicinity of an industrial area in Lagos, Nigeria

Groundwater (well water) from a residential area within the vicinity of an industrial estate in Lagos, Nigeria were sampled and analysed by Flame Atomic Absorption Spectroscopy for their heavy metals content. This was with a view of assessing the quality of the water, which was being used for domestic activities, especially, drinking usually without treatment. Total trace metal determination by mineral acid digestion of water samples was applied. This method proved to be better than an extractive concentration technique in the quality assurance protocols with the recovery range being 90.7 ± 0.006–97.6 ± 0.003%. Mean concentration of trace metals in water samples ranged from Fe: 0.05–0.47 mg l⁻¹; Al: 0.1–1.54 mg l⁻¹; Cu: 0.14–1.39 mg l⁻¹; Zn: 0.04–0.43 mg l⁻¹; Cd: trace–0.02 mg l⁻¹; Pb: trace–0.03 mg l⁻¹, Mn: 0.01–0.18 mg l⁻¹ and Ni: 0.02–0.11 mg l⁻¹. Physical parameters of water samples examined were within the drinking water safety limits except for conductivity. Results generally indicate the presence of heavy metal constituents in groundwater samples. Detection of metals such as cadmium and lead which have serious health implications above WHO and USEPA limits in drinking water gives cause for concern.