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Drinking water scarcity is an ever-increasing global concern. This issue appears as a greater threat to the countries with no access to sea water resources or rivers, since their potential water resources are only limited to ground waters only. There are serious concerns with the treatment of ground water resources, including landfill leachates, agricultural contaminations (pesticides, herbicides, and fertilizers), and rural contaminations. Membrane separation has been proved to be the governing technology in water and wastewater treatment plants, as these methods are responsible for more than half of the market share of the world's desalination capacity. This study intends to offer a holistic view of the groundwater contamination with specific focus on Saskatchewan province in Canada, and the recent efforts in the groundwater treatment using thin film composite membrane technology. This study begins with an introduction of the general aspects of ground water and membrane separation, polluting agents, and their sources. It is followed by a discussion of Saskatchewan's groundwater status and various issues. Furthermore, the recent research that became available since 2010 is reviewed in details and the results are summarized with respect to purification efficiency. Different affecting parameters in a groundwater-thin film composite system are synthesized and an in-depth overview is presented. 相似文献
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Because of recent volume increases, appropriate management of plastic recycling, which generates various organic compounds, is required to ensure the chemical safety of the processes. The processing temperature and resin type are the important factors determining both the efficiency of the processes and the emission of chemicals. Therefore, we studied the thermal degradation of various plastics at various temperatures from 70 to 300 °C under oxygen-present conditions to identify the semi-volatile organic compounds (SVOCs) emitted and to understand their thermal behaviors. The plastics examined were nitrogen-containing resins, such as polyamide 6, polyurethane, melamine formaldehyde, urea formaldehyde and acrylonitrile-butadiene-styrene. Major commodity plastics were also investigated for comparison. In total, more than 500 SVOCs were detected as emissions from plastics. While various nitrogen-containing SVOCs were detected from nitrogen-containing resins, the major commodity plastics released only these, which possibly were included as additives. These results indicate that the nitrogen atoms in the SVOCs emitted originated from the resins and additives, and not from ambient air at low temperature. As a result of the detection of raw materials, degradation chemicals and by-products of the polymers in the emissions, we found that the variation in chemical species is dependent on the resins. Additives were also emitted from all the resins, meaning that these chemicals were also released to the environment at the temperature examined. In most cases, the numbers and concentrations of SVOCs increased with increasing heating temperature. The variation of thermal behaviors of SVOCs was related to the origins and chemical species of SVOCs. 相似文献
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间歇式活性污泥法在处理聚酰胺废水中的应用 总被引:2,自引:0,他引:2
李明哲 《石油化工环境保护》2000,23(4):8-10
在实验研究的基础上,将间歇式活性污泥处理工艺(简称SBR法)应用于聚酰胺废水的治理工程中。运行实践表明,该处理工艺对于聚酰胺高浓度有机废水具有良好的去除效率,并且该处理工艺具有投资少,运行可靠,管理方便等优点。 相似文献
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Naoko Yamano Atsuyoshi Nakayama Norioki Kawasaki Noboru Yamamoto Seiichi Aiba 《Journal of Polymers and the Environment》2008,16(2):141-146
We identified a biodegrading microorganism of polyamide (nylon) 4, a linear polymer of γ-aminobutyric acid (GABA). From activated
sludge, the biodegrading bacteria strains of Pseudomonas sp. were isolated and identified by their taxonomic characteristics and nucleotide sequences of 16S rDNA. One strain, ND-11,
was grown on a minimal medium containing polyamide 4 (PA4) as the sole carbon source. The strain produced GABA as a degradation
intermediate, as identified by analyzing the NMR spectra of degraded products. The culture supernatant of strain ND-11 degraded
the emulsified PA4 completely within one day. These results suggest that the ND-11 strain degraded PA4 using its extracellular
enzymes to hydrolyze amide bonds. 相似文献
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Ivan Iarossi Paul R. Amyotte Faisal I. Khan Luca Marmo Ashok G. Dastidar Rolf K. Eckhoff 《Journal of Loss Prevention in the Process Industries》2013,26(6):1627-1633
The current research is aimed at investigating the explosion behavior of hazardous materials in relation to aspects of particulate size. The materials of study are flocculent (fibrous) polyamide 6.6 (nylon) and polyester (polyethylene terephthalate). These materials may be termed nontraditional dusts due to their cylindrical shape which necessitates consideration of both particle diameter and length. The experimental work undertaken is divided into two main parts. The first deals with the determination of deflagration parameters for polyamide 6.6 (dtex 3.3) for different lengths: 0.3 mm, 0.5 mm, 0.75 mm, 0.9 mm and 1 mm; the second involves a study of the deflagration behavior of polyester and polyamide 6.6 samples, each having a length of 0.5 mm and two different values of dtex, namely 1.7 and 3.3. (Dtex or decitex is a unit of measure for the linear density of fibers. It is equivalent to the mass in grams per 10,000 m of a single filament, and can be converted to a particle diameter.) The explosibility parameters investigated for both flocculent materials include maximum explosion pressure (Pmax), size-normalized maximum rate of pressure rise (KSt), minimum explosible concentration (MEC), minimum ignition energy (MIE) and minimum ignition temperature (MIT). ASTM protocols were followed using standard dust explosibility test equipment (Siwek 20-L explosion chamber, MIKE 3 apparatus and BAM oven). Both qualitative and quantitative analyses were undertaken as indicated by the following examples. Qualitative observation of the post-explosion residue for polyamide 6.6 indicated a complex interwoven structure, whereas the polyester residue showed a shiny, melt-type appearance. Quantitatively, the highest values of Pmax and KSt were obtained at the shortest length and finest dtex for a given material. For a given length, polyester displayed a greater difference in Pmax and KSt at different values of dtex than polyamide 6.6. Long ignition delay times were observed in the BAM oven (MIT measurements) for polyester, and video framing of explosions in the MIKE 3 apparatus (MIE measurements) enabled observation of secondary ignitions caused by flame propagation after the initial ignition occurring at the spark electrodes. 相似文献
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