Leaching behaviour of different scrap materials at recovery and recycling companies: Full-, pilot- and lab-scale investigation

Scrap material recovery and recycling companies are confronted with waste water that has a highly fluctuating flow rate and composition. Common pollutants, such as COD, nutrients and suspended solids, potentially toxic metals, polyaromatic hydrocarbons and poly chlorinated biphenyls can exceed the discharge limits. An analysis of the leaching behaviour of different scrap materials and scrap yard sweepings was performed at full-scale, pilot-scale and lab-scale in order to find possible preventive solutions for this waste water problem. The results of these leaching tests (with concentrations that frequently exceeded the Flemish discharge limits) showed the importance of regular sweeping campaigns at the company, leak proof or covered storage of specific scrap materials and oil/water separation on particular leachates. The particulate versus dissolved fraction was also studied for the pollutants. For example, up to 98% of the polyaromatic hydrocarbons, poly chlorinated biphenyls and some metals were in the particulate form. This confirms the (potential) applicability of sedimentation and filtration techniques for the treatment of the majority of the leachates, and as such the rainwater run-off as a whole.     

Industrial wastewater analysis: a toxicity-directed approach

Methods of toxicity-directed analysis have been developed for the characterization and identification of toxic organic constituents in industrial wastewater. Sequential solid-phase extraction is followed by high-performance liquid chromatography (HPLC) fractionation or by automated multiple development thin-layer chromatography fractionation (AMD–TLC) of the toxic extracts. Toxic fractions were finally analyzed by gas chromatography–mass spectroscopy (GC–MS). Toxicity was detected before each of the analytical steps by the bioluminescence inhibition of Vibrio fischeri, which was performed on microtiter plates and on the developed TLC plates. While sequential extraction broadens the polarity range of the procedure, the new variants of the luminescence test make the method very versatile and fast. The potential of this kind of toxicity-directed analysis with respect to resolution and polarity of analytes is discussed and applications to partial effluents of a tannery, to molasses wastewater and a spent dyeing bath are presented. A variety of benzothiazoles and more polar organics were identified as major toxic compounds in tannery effluents. It is shown that the procedures are well suited to detect individual toxic components in complex industrial wastewaters. The use of LC-MS is proposed to extend the polarity range of the final identification step. ©     

Occurence and Distribution of Polycyclic Aromatic Hydrocarbons in Ankara Precipitation

Urban atmospheric environment contains many trace organic pollutants that are related to the incomplete fuel combustion in domestic heating, industrial plants and automobile traffic. Removal of these pollutants from the atmosphere takes place through wet and dry deposition as well as chemical transformations. In this study, concentrations of polycyclic aromatic hydrocarbons (PAHs) in wet deposition samples were determined at an urban site of Turkey. Wet and dry deposition samples were collected using Andersen Rain Sampler. The sampler was modified accordingly for the collection of organic pollutants. Collected samples were preconcentrated by using solid phase extraction (SPE) disks and consecutively analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). Among the 13 compounds quantified in this study, anthracene, fluoranthene, and pyrene were found more frequently and at elevated concentrations (202, 271 and 260 ng L^-1 mean concentrations, respectively).Concentrations of PAHs were found to be high in winter period.     

Substance-specific detection and pursuit of non-eliminable compounds during biological treatment of waste water from the pharmaceutical industry

Up to now comprehensive examination and assessment of the elimination behaviour of many different pollutants in biological waste water treatment failed above all because of limited possibilities to pursue polar organic compounds of anthropogenic and biogenic origin. In this case the behaviour of waste water constituents during the treatment of waste water from the pharmaceutical industry was studied with the help of mass-spectrometric detection (MS). After completest possible extraction and concentration by liquid/liquid and solid phase extraction (SPE) from samples of influent and effluent of a pilot plant, substance-specific determination and identification was done after chromatographic separation and with the help of mixture analysis, respectively. Separation by gas chromatography coupled with MS was applied to pursue the organic compounds, which are volatile without decomposition, during the waste water treatment process. Flow injection analysis (FIA) bypassing the analytical column combined with soft-ionizing interfaces served for screening of the polar compounds. Then they were separated by liquid chromatographic methods to recognize changes in the qualitative and quantitative compound spectrum. Mixture analysis by FIA combined with tandem mass spectrometry (FIA/MS/MS) was used for identification of the pollutants without previous chromatographic separation. A laboratory-made daughter ion library helped to identify some of the poorly eliminable pollutants detected. The presentation of the monitoring procedures applied was made in such a way that the treatment results were visually recognizable. Due to the use of time-saving FIA/MS, this method may serve for substance-specific monitoring of the treatment of possibly problematic waste waters. ©     

Development of a simple and sensitive method for the characterization of odorous waste gas emissions by means of solid-phase microextraction (SPME) and GC-MS/olfactometry

A solid-phase microextraction (SPME) method has been developed for the extraction of odorous compounds from waste gas. The enriched compounds were characterized by gas chromatography-mass spectrometry (GC-MS) and gas chromatography followed by simultaneous flame ionization detection and olfactometry (GC-FID/O). Five different SPME fiber coatings were tested, and the carboxen/polydimethylsiloxane (CAR/PDMS) fiber showed the highest ability to extract odorous compounds from the waste gas. Furthermore, parameters such as exposure time, desorption temperature, and desorption time have been optimized. The SPME method was successfully used to characterize an odorous waste gas from a fat refinery prior to and after waste gas treatment in order to describe the treatment efficiency of the used laboratory scale plant which consisted of a bioscrubber/biofilter combination and an activated carbon adsorber. The developed method is a valuable approach to provide detailed information of waste gas composition and complements existing methods for the determination of odors. However, caution should be exercised if CAR/PDMS fibers are used for the quantification of odorous compounds in multi-component matrices like waste gas emissions since the relative affinity of each analyte was shown to differ according to the total amount of analytes present in the sample.     

Destruction of PAHS from soil by using pressurized hot water extraction coupled with supercritical water oxidation

Chemical processes utilizing water both as extraction solvent and reaction medium are promising "Green Chemistry" alternatives to conventional techniques. Equipment for on-line coupled hot water extraction and supercritical water oxidation was constructed to extract polyaromatic hydrocarbons and toluene from sea sand followed by oxidation using hydrogen peroxide. The effectiveness of the technique is based on the physico-chemical properties of heated and pressurized water. Extraction efficiency increased with temperature and time; the best results were obtained at 300 degrees C with 40 min extraction time. In the oxidation stage, conversion of the PAHs increased with reaction time and oxidant concentration and the best conversion (97.0-99.9%, depending on the compound) was obtained at 425 degrees C with 43 s reaction time. Benzaldehyde and benzoic acid were the most abundant reaction intermediates in the oxidation process. In addition, phenol, p-cresol, and benzyl alcohol were found as intermediates. The intermediates originated mainly from toluene, which was present in much greater concentration than PAHs in the reaction medium.     

炉排炉焚烧垃圾过程中主要污染物的控制

概述了二恶英、重金属、酸性气体、灰渣等垃圾焚烧的主要污染物，以二段式（往复）焚烧炉为例，介绍了炉排炉焚烧处理工艺和污染控制设备。提出通过控制垃圾焚烧条件、尾气处理以及吸附等方法，可以有效控制二恶英类污染物的排放；重金属的控制可以用除尘器或使用相应的吸附剂处理；采用较为成熟的烟气处理技术，可以控制处理酸性气体；灰渣可采用固化稳定化或酸提取法处置。     

Groundwater Remediation via Marcro Porous Polymer Extraction

Akzo Nobel's Macro Porous Polymer Extraction (MPPE) technology effectively removes dissolved hydrocarbons from groundwater via liquid-liquid extraction with an innovative medium. Excellent performance in removal of chlorinated, aromatic, and aliphatic solvents, coupled with simple, robust design, make MPPE an attractive process for groundwater remediation applications. Hydrocarbon-contaminated water is passed through a column packed with MPPE particles. An extraction fluid, immobilized within the polymer matrix, removes the hydrocarbons from the water. All hydrocarbons with affinity for the extraction fluid (compared to water) are removed. Regeneration is accomplished in situ with low-pressure steam. The steam volatilizes the hydrocarbons but not theimmobilized extraction fluid. Volatilized hydrocarbons are condensed and then separated from condensate by gravity. The hydrocarbon product is available for recycle or reuse. MPPE systems achieve removal efficiencies of 99.99 percent for wide varieties and combinations of aliphatic, aromatic, and chlorinated compounds. For a broad range of mass loadings and effluent requirements, especially rigorous ones, the MPPE system offers lower investment and operating costs than traditional water treatment technologies. Currently, 14 industrial units are running or under construction in the United States and Europe. Eight of these are treating groundwater.     

Waste on the roadside, 'poi-sute' waste: its distribution and elution potential of pollutants into environment

Waste on the roadside, 'poi-sute' waste, was collected in a typical suburb in Japan (Ueda city, the sampling course: 3.2 km). The distribution, characterization of the 'poi-sute' waste and the loading of pollutants from the waste were studied. The average number of pieces of total waste was 690 pieces a month, and 220 pieces of waste were dumped a month per km. There was a tendency for much waste to be discarded around shops staying open until late at night. Regarding the sorts of the waste, cigarette butts are the most prevalent (the average was 150 cigarette butts/km/mo), and second was plastic materials. As for the weight, cigarette butts, plastics and papers were at a similar level (about 90 g/km/mo). The elution of arsenic (0.041 mg/L) and nicotine (3.8 mg/L) was ascertained by a dissolution test of 'poi-sute' cigarette butts obtained by sampling. Furthermore, the loading of heavy metals, such as lead, copper, chromium and cadmium, and polycyclic aromatic hydrocarbons (PAHs) from cigarette butts into the environment was confirmed. The load potentials of heavy metals were 0.020-1.7 mg/km/mo, and that of total-polyaromatic hydrocarbons was 0.032 mg/km/mo. These results indicate that the 'poi-sute' waste has a harmful influence on the environment.     

Successful solid-phase bioremediation of petroleum-contaminated soil

Biological processes have been used to remediate petroleum hydrocarbons, pesticides, chlorinated solvents, and halogenated aromatic hydrocarbons. Biological treatment of contaminated soils may involve solid-phase, slurry-phase, or in situ treatment techniques. This article will review the general principle of solid-phase bioremediation and discuss the application of this technique for the cleanup of total petroleum hydrocarbons on two sites. These remedial programs will reduce total petroleum hydrocarbon contamination from the mean concentration of 2,660 ppm to under the 200-ppm cleanup criteria for soil and under the 15-ppm cleanup criteria for groundwater. Over 32,000 yards of soil have been treated by solid-phase treatment to date. The in situ system operation is effectively producing biodegradation in the subsurface. The project is approximately one-third complete.     

电子废弃物中持久性有机污染物分析检测方法的研究进展

针对目前电子废弃物中持久性有机污染物(POPs)尚未形成有效快速分析检测方法的问题,介绍了溶剂萃取、固相萃取、微波萃取和超临界流体萃取等POPs前处理技术的研究进展,总结了POPs的分析方法,如:气相色谱、液相色谱、气相色谱-质谱法、高分辨率气相色谱-高分辨质谱法等化学分析方法,以及生物传感器测定法、表面胞质团共振检测法、酶联免疫检测法等生物分析方法。分析了各方法的优劣,并提出了展望。     

The efficacy of an oxidation pond in mineralizing some industrial waste products with special reference to fluorene degradation: a case study

The efficacy of the oxidation pond on the outskirts of the 10th of Ramadan, the main industrial city, in Egypt was examined. Samples of wastewater collected from the inlet and the outlet were screened for some priority pollutants. Acenaphthene and fluorene were the most frequently detected polycyclic aromatic hydrocarbons, while dimethyl phthalate was the most frequently detected phthalate ester. The spectrum of pollutants, their concentrations and frequencies were similar in the inlet and the outlet, indicating an inferior mineralization capability of the pond. Several degradative bacterial strains were isolated from the pond and grown on M56 minimal media supplemented with different pollutants as the carbon source. The efficacy of pure and mixed cultures to break down fluorene, the most frequently detected pollutant was examined. Fluorene degradation was fast in the first 10 days, then followed by a slow phase. Mixed culture had a higher rate of fluorene degradation in comparison to pure cultures. High performance liquid chromatography analysis of fluorene degradation showed three degradative metabolites. But GC/MS analysis detected one compound, identified as acetamide. The present work has indicated the poor efficacy of the pond. Lack of primary treatment of industrial effluent at factory level, coupled with shock loads of toxicants that may damage the microorganisms and their degradative capabilities are presumably main factors behind such inferior performance. Moreover, the type of pollutants discharged into the pond tend to fluctuate and change depending on the rate from the factories discharge and work shifts. Such irregular feeding of persistent pollutants may have led to a wash out of specialized strains of bacteria capable to degrade such persistent pollutants.     

自来水厂常规净水工艺除有机污染物效果的监测

采用ＧＣ－ＭＳ／ＣＯＭＰ技术对宁波梅林水厂姚江水源水及各净水工序出水中的有机污染物进行了监测,结果表明,姚江水中主要有机污染物为苯系物、多环芳烃、染料及中间体等,水厂现有的常规净水工艺对上述有机污染物的去除率较低。     

催化氧化技术在橡胶废气处理中的应用

采用催化氧化技术处理热塑性丁苯橡胶( SBS)生产装置D线后处理单元废气,废气的非甲烷总烃去除率和环己烷去除率均达到98％以上,非甲烷总烃质量浓度达到DB11/447-2007《炼油与石油化学工业大气污染物排放标准》的要求(小于100 mg/m3).对SBS生产装置凝聚单元进行两釜流程改三釜流程后,催化氧化反应器入口非甲烷总烃质量浓度由( 3.84～5.82)×103 mg/m3降至( 2.48～2.63)×103 mg/m3,反应器出口非甲烷总烃质量浓度均小于50 mg/m3.凝聚单元改造并采用催化氧化技术处理废气后,每年节约费用约80万元.     

Status and trends in bioremediation treatment technology

This article is a critical analysis of the treatment potential of bioremediation technology to degrade eight major environmental pollutants, polycyclic aromatic hydrocarbons, phenols, pentachlorophenols, creosote, polychlorinated biphenyls, trichloroethylene, chlorobenzoates, and chlorophenols. The discussion includes information on transformation mechanisms, identification of intermediate metabolites, elucidation of partial or complete pathways, effects of environmental parameters, as well as current and future industrial application. Results indicate that bioremediation used in conjunction with other physical and chemical treatment methodologies can effectively transform most prevalent nonchlorinated organic contaminants and some chlorinated contaminants, such as creosote and pentachlorophenol, into innocuous materials. Successful biodegradation of several other chlorinated organic compounds, notably polychlorinated biphenyls and trichloroethylene, is currently possible only under controlled laboratory conditions. Future successful field applications, however, appear promising.     

Pyrolysis of waste tyres: A review

Approximately 1.5 billion tyres are produced each year which will eventually enter the waste stream representing a major potential waste and environmental problem. However, there is growing interest in pyrolysis as a technology to treat tyres to produce valuable oil, char and gas products. The most common reactors used are fixed-bed (batch), screw kiln, rotary kiln, vacuum and fluidised-bed. The key influence on the product yield, and gas and oil composition, is the type of reactor used which in turn determines the temperature and heating rate. Tyre pyrolysis oil is chemically very complex containing aliphatic, aromatic, hetero-atom and polar fractions. The fuel characteristics of the tyre oil shows that it is similar to a gas oil or light fuel oil and has been successfully combusted in test furnaces and engines. The main gases produced from the pyrolysis of waste tyres are H₂, C₁–C₄ hydrocarbons, CO₂, CO and H₂S. Upgrading tyre pyrolysis products to high value products has concentrated on char upgrading to higher quality carbon black and to activated carbon. The use of catalysts to upgrade the oil to a aromatic-rich chemical feedstock or the production of hydrogen from waste tyres has also been reported. Examples of commercial and semi-commercial scale tyre pyrolysis systems show that small scale batch reactors and continuous rotary kiln reactors have been developed to commercial scale.     

火电厂烟气汞形态转化机理及控制方法

汞是煤中最易挥发的重金属元素之一,燃烧产物中汞的排放为火电厂锅炉汞污染的主流。烟气中的汞主要采用活性炭或者其他吸附剂、飞灰再循环、湿法烟气脱硫装置等手段来去除,但普遍存在吸附剂价格昂贵、经济效应不高,具体脱除效应不明显、仅适用中小型火电厂锅炉等实际问题。为配合脱汞市场,需要在完善测试手段和控制手段的基础上,着重解决多组分污染物联合脱除汞反应的竞争机制和活性/选择性调控规律、吸收剂固体表面物理化学、大容积/大流量反应器内超低浓度污染物的富集/反应机理等关键技术问题。在火电厂烟气零价汞形态转化机理、汞迁移转化动力学模型的研究以及高效价廉吸附剂的开发等方面取得突破,开发具有自主知识产权的新型燃煤电厂烟气中汞排放控制方法。     

Thermal cracking of oils from waste plastics

Thermal cracking of decomposed waste plastic oil produces a good yield of olefins. The solvent extraction of such waste plastic oil seems to be efficient for increasing gas yields and recycling monomers. To assess the potential of monomer recovery from municipal waste plastics, the oils were cracked using a laboratory-scale quartz-tube reactor. The waste plastic oils were provided by two commercial plants of the Sapporo Plastic Recycle Co. and the Dohoh Recycle Center Co. in Japan. A model waste plastic oil made in a laboratory was also examined. Yields of ethene, propene, and other products were measured at different temperatures. Two-step pyrolysis reduces coking compared with the direct thermal degradation of plastics. The raffinates from waste plastic oils extracted by sulfolane were also cracked. The primary products were almost the same as those from nontreated oils. The maximum total gas yield was 78wt%–85wt% at 750°C, an increase of about 20wt% compared with that of nonextracted oil. Solvent extraction removes stable aromatic hydrocarbons such as styrene, which is more coked than cracked.     

Vanadium recovery from oil fly ash by leaching, precipitation and solvent extraction processes

In order to reduce the environmental impact due to land disposal of oil fly ash from power plants and to valorize this waste material, the removal of vanadium was investigated using leaching processes (acidic and alkaline treatments), followed by a second step of metal recovery from leachates involving either solvent extraction or selective precipitation. Despite a lower leaching efficiency (compared to sulfuric acid), sodium hydroxide was selected for vanadium leaching since it is more selective for vanadium (versus other transition metals). Precipitation was preferred to solvent extraction for the second step in the treatment since: (a) it is more selective; enabling complete recovery of vanadate from the leachate in the form of pure ammonium vanadate; and (b) stripping of the loaded organic phase (in the solvent extraction process) was not efficient. Precipitation was performed in a two-step procedure: (a) aluminum was first precipitated at pH 8; (b) then ammonium chloride was added at pH 5 to bring about vanadium precipitation.