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531.
532.
Incineration of municipal solid waste (MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction as well as a source of renewable energy. In the process fly and bottom ash is generated as a waste material. The ash residue may vary greatly in composition depending on the type of waste incinerated and it can contain elevated levels of harmful contaminants such as heavy metals. In this study, the ecotoxicity of a weathered, untreated incineration bottom ash was characterized as defined by the H14 criterion of the EU Waste Framework Directive by means of an elemental analysis, leaching tests followed by a chemical analysis and a combination of aquatic and solid-phase bioassays. The experiments were conducted to assess the mobility and bioavailability of ash contaminants. A combination of aquatic and terrestrial bioassays was used to determine potentially adverse acute effects of exposure to the solid ash and aqueous ash leachates. The results from the study showed that the bottom ash from a municipal waste incineration plant in mid-Sweden contained levels of metals such as Cu, Pb and Zn, which exceeded the Swedish EPA limit values for inert wastes. The chemical analysis of the ash leachates showed high concentrations of particularly Cr. The leachate concentration of Cr exceeded the limit value for L/S 10 leaching for inert wastes. Filtration of leachates prior to analysis may have underestimated the leachability of complex-forming metals such as Cu and Pb. The germination test of solid ash and ash leachates using T. repens showed a higher inhibition of seedling emergence of seeds exposed to the solid ash than the seeds exposed to ash leachates. This indicated a relatively low mobility of toxicants from the solid ash into the leachates, although some metals exceeded the L/S 10 leaching limit values for inert wastes. The Microtox® toxicity test showed only a very low toxic response to the ash leachate exposure, while the D. magna immobility test showed a moderately high toxic effect of the ash leachates. Overall, the results from this study showed an ecotoxic effect of the solid MSW bottom ash and the corresponding ash leachates. The material may therefore pose an environmental risk if used in construction applications. However, as the testing of the solid ash was rather limited and the ash leachate showed an unusually high leaching of Cr, further assessments are required in order to conclusively characterize the bottom ash studied herein as hazardous according to the H14 criterion. 相似文献
533.
Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review 总被引:1,自引:0,他引:1
Constantin Papastefanou 《Journal of environmental radioactivity》2010,101(3):191-200
Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of 40K and of 238U, 232Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y−1), the major part of which (99 %) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg−1 for 238U, from 44 to 255 Bq kg−1 for 226Ra, from 59 to 205 Bq kg−1 for 210Pb, from 9 to 41 Bq kg−1 for 228Ra (232Th) and from 59 to 227 Bq kg−1 for 40K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3-1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg−1 for 238U, from 142 to 605 Bq kg−1 for 226Ra, from 133 to 428 Bq kg−1 for 210Pb, from 27 to 68 Bq kg−1 for 228Ra (232Th) and from 204 to 382 Bq kg−1 for 40K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5 man-Sv (GW a)−1 for typical old and modern coal-fired power plants, respectively. 相似文献
534.
A comparative adsorption/biosorption study of mono-chlorinated phenols onto various sorbents 总被引:9,自引:0,他引:9
The potential use of dried activated sludge and fly ash as a substitute for granular activated carbon for removing mono-chlorinated phenols (o-chlorophenol and p-chlorophenol) was examined. The pollutant binding capacity of the adsorbent/biosorbent was shown to be a function of substituted group, initial pH and initial mono-chlorinated phenol concentration. The working sorption pH value was determined as 1.0 and the equilibrium uptake increased with increasing initial mono-chlorinated phenol concentration up to 500 mg dm(-3) for all the mono-chlorinated phenol-sorbent systems. The suitability of the Freundlich, Langmuir and Redlich-Peterson adsorption models to the equilibrium data were investigated for each mono-chlorinated phenol-sorbent system. The results showed that the equilibrium data for all the mono-chlorinated phenol-sorbent systems fitted the Redlich-Peterson model best within the concentration range studied. 相似文献
535.
Metallic-phase lead in slag of municipal solid waste incineration ash and leaching characteristics 总被引:2,自引:0,他引:2
Metallic phases in slags and their influence on the leaching characteristics were investigated. The proportions of metallic
phase in four slags were 0.028%, 0.24%, 1.87%, and 3.05% by weight. The lead content was 10–248 mg/kg in bulk slag after metal
removal, while in the metallic phase it was 579–7390 mg/kg. Lead concentrations in the metallic phase were more than ten times
higher than in slags after metal removal. Lead was distributed in the metallic phase at 2.0%, 8.3%, 10.3%, and 47.4%. The
concentrations of all metallic elements in metallic phases were much higher than in bulk slag. Iron, copper, and nickel had
accumulated in magnetic metals, while aluminum and zinc were found in nonmagnetic metals. As regards chromium, manganese,
lead, and tin, the proportion of metallic phases depended on the slag samples. By removing metallic phases, both water and
pH 4 leachable lead decreased. The basic principles of melting residues containing lead are the separation of lead as a metal
in reductive melting, and the containment of lead ions into uniform glassy particles in oxidization melting. Melting slag
can be seen to contribute to environmental preservation by facilitating the recycling of materials through the separation
of metals from melting slag.
Received: February 21, 2000 / Accepted: July 27, 2000 相似文献
536.
537.
538.
Introduction The impact of mercury on the environment and thephysiological health of human is well documented(Laudal,2000; Poissant, 2002; Galbreath, 2000; Palusova, 1991).Mercury, especially methyl mercury, has high affinities forfatty tissue… 相似文献
539.
电厂煤燃烧后元素硒的分布及对环境的贡献 总被引:15,自引:0,他引:15
对电厂煤、除尘器飞灰、渣及不同粒径的烟道飞灰中痕量元素硒进行研究.化学分析表明,硒在渣和除尘器飞灰中亏损而在细飞灰中富集,尤其在>19.0μm的飞灰中明显富集,富集系数达到5.15,造成这种现象的原因一是挥发性元素的挥发-凝结作用,二是燃烧产物在燃烧气流中停留的时间,三与飞灰颗粒形态有关,>19.0μm的飞灰中多孔颗粒可能是造成其富集的原因.逐级化学提取实验表明,煤中硒主要具有机相关性(69.7%),这也是硒挥发性高的一个主要原因;物质平衡计算显示煤中16.5%的硒随气流直接排放入大气,细飞灰中的硒只占1.1%,且大部分在>19.0μm的飞灰中,影响范围小,渣中硒对周围环境的影响更小,飞灰中的硒具有一定的迁移性,也许可以用来改善缺硒土壤. 相似文献
540.
利用MSWI飞灰构建新型填埋固化基质的研究 总被引:1,自引:0,他引:1
介绍了以MSWI飞灰为主要组分,利用富铝组分调控所构建的Friedel-ettringite为主导相的新型固化体系,考察了固化体系的抗压强度并用美国EPA毒性浸出实验(TCLP),评价固化材料中重金属的浸出特性,使用XRD、DTG分析了固化体系的微观矿物相,FTIR图谱对固化体系矿物相的有关基团振动谱带进行比较,通过重金属的化学形态分布了解重金属在其中的赋存状态,结果表明,新体系可以通过矿物相的晶体化合作用对Pb、Cd、Zn重金属进行有效束缚,实现稳定固化这种新型固化体系可望用于MSWI飞灰与其它重金属类危险废物的填埋共处置。 相似文献