Treatment and resource recovery from inorganic fluoride-containing waste produced by the pesticide industry

The rapid development of the fluorinated pesticide industry has produced a large amount of fluorine-containing hazardous waste, especially inorganic fluoride-containing waste(IFCW). A two-step process, including extraction and recovery, was developed to recover fluorine as synthetic cryolite from IFCW produced by the pesticide industry. The optimum conditions for extraction were found to be a temperature of 75℃, an initial p H(p Hi) of 12, a4-hr incubation time and a liquid-to-solid ratio of 40 m L/g; these conditions resulted in a fluorine extraction ratio of 99.0%. The effects of p H and the F/Al molar ratio on fluorine recovery and the compositional, mineralogical and morphological characteristics of the cryolite products were investigated. Field-emission scanning electron microscopy of recovered precipitates showed changes in morphology with the F/Al molar ratio. Coupling Fourier transform and infrared spectroscopy, X-ray diffraction indicated that the formation of Al F3-6was restricted as increasing p H. Both the amount of fluorine recovered and the quality of the cryolite were optimized at initial p H = 3 and a F/Al molar ratio 5.75. This study proposed a reliable and environmentally friendly method for the treatment of fluoridecontaining wastes, which could be suitable for industrial applications.     

Treatment and resource recovery from inorganic fluoride-containing waste produced by the pesticide industry

The rapid development of the fluorinated pesticide industry has produced a large amount of fluorine-containing hazardous waste, especially inorganic fluoride-containing waste (IFCW). A two-step process, including extraction and recovery, was developed to recover fluorine as synthetic cryolite from IFCW produced by the pesticide industry. The optimum conditions for extraction were found to be a temperature of 75°C, an initial pH (pH_i) of 12, a 4-hr incubation time and a liquid-to-solid ratio of 40 mL/g; these conditions resulted in a fluorine extraction ratio of 99.0%. The effects of pH and the F/Al molar ratio on fluorine recovery and the compositional, mineralogical and morphological characteristics of the cryolite products were investigated. Field-emission scanning electron microscopy of recovered precipitates showed changes in morphology with the F/Al molar ratio. Coupling Fourier transform and infrared spectroscopy, X-ray diffraction indicated that the formation of AlF₆^3 − was restricted as increasing pH. Both the amount of fluorine recovered and the quality of the cryolite were optimized at initial pH = 3 and a F/Al molar ratio 5.75. This study proposed a reliable and environmentally friendly method for the treatment of fluoride-containing wastes, which could be suitable for industrial applications.     

气体燃料发动机发展对中国温室气体减排贡献的生命周期分析

为分析气体燃料发动机的温室气体减排能力,应用生命周期分析方法计算了不同燃料的生命周期温室气体排放量,并据此计算了不同发动机的温室气体排放量.建立了气体燃料发动机“最大限度发展”和“不发展”两种情形.据此预测了2020年中国气体燃料发动机的温室气体减排效果,估算了2020年气体燃料发动机的耗气量占气体供应量的比重.结果显示,在最大限度发展情形下,气体燃料发动机将分别为城市公共交通、船舶动力和火力发电领域减少约7.47, 18.25, 450.1Mt CO2e的温室气体,减排量占全国减排目标的5.3%.气体燃料发动机将分别消耗15%的天然气、18.5%的煤层气和50%的垃圾填埋气供应量.考虑我国气体燃料资源结构情况及供应形势,推广气体燃料发动机是切实可行的.     

Supercritical fluid technology as a sustainable alternative method for textile dyeing:An approach on waste,energy, and CO2 emission reduction

The clothing industry is considered one of the most polluting industries on the planet due to the high consumption of water,energy,chemicals/dyes,and high generation of solid waste and effluents.Faced with environmental concerns,the textile ennoblement sector is the most critical of the textile production chain,especially the traditional dyeing processes.As an alternative to current problems,dyeing with supercritical CO₂(scCO₂) has been presented as a clean and efficient pr...     

Treatment of desizing wastewater from the textile industry by wet air oxidation

This paper describes the application of wet air oxidation to the treatment of desizing wastewater from two textile companies. A two-liter high temperature, high pressure autoclave reactor was used in the study. The range of operating temperatures examined was between 150 and 290℃, and the partial pressure of oxygen ranged from 0. 375 to 2.25 MPa. Variations in pH,CODCr and TOD content were monitored during each experiment and used to assess the extent of conversion of the process. The effects of temperature, pressure and reaction time were explored extensively. More than 90 ％ CODCr reduction and 80 ％ TOC removal have been obtained. The results have also been demonstrated that WAO is a suitable pre-treatment methods due to improvement of the BOD5/CODCr ratio of desizing wastewater. The reaction kinetics of wet air oxidation of desizing wastewater has been proved to be two steps, a fast reaction followed by a slow reaction stage.     

Treatment of desizing wastewater from the textile industry by wet air oxidation

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Use of microbes for cost reduction of metal removal from metals and mining industry waste streams

Acid-rock drainage (ARD) – also known as acid-mine drainage (AMD) – results from the exposure of sulfide minerals, particularly pyritic and pyrrhotitic minerals, to atmospheric oxygen and water. AMD directly impacts tens of thousands of kilometers of streams, lakes and estuaries throughout the world. The impacted water bodies tend to have elevated concentrations of metals in the water column or sediments, and are also stressed by significant inputs of hydrogen ions.There are several conventional treatment technologies available. The most common is chemical precipitation using lime or other basic substances. These systems produce large volumes of wet sludge that often require drying facilities to concentrate the metal hydroxide sludge. Wetland treatment systems have also been used for several decades to treat AMD. Recent developments and improvements have resulted in construction of bioreactors that have a smaller footprint, and treat the metals and acidity more effectively.Many studies have demonstrated that the primary removal mechanisms for the metals are sulphate-reducing bacteria (SRB). These microbes facilitate the conversion of sulphate to sulphide. The sulphides react with metals to precipitate them as metal sulfides, many of which are stable in the anaerobic conditions of the treatment system.Plants have been shown to remove metals by uptake or oxidative precipitation near the roots. Plants seem to account for only a small percentage of the metal removal capacity of the wetland treatment systems. Adsorption of metals to the organic substrates of the treatment systems can result in metal removal, but adsorption capacity is saturated in short periods of time.High oxygen, low pH waters often enter the treatment systems. The SRB are obligate anaerobes which prefer conditions between pH 5 and 8. Thus, the input water characteristics could impact the efficiency and life expectancy of the treatment systems. The most important characteristic of input waters seems to be pH. Low oxygen of the influent waters did not enhance treatment capabilities. Low pH waters do reduce the capacity of the treatment systems to treat metals effectively.Oxyanions such as chromate and arsenate can be removed using the wetland treatment system (passive bioreactor) technology. Arsenic is removed as an arsenic sulfide compound and chromate is reduced to Cr(III) and precipitated as a hydroxide.The passive bioreactor – wetland treatment system – offers a less expensive alternative to the conventional chemical precipitation technologies. There still are problems of system hydraulics and useful life to be addressed.     

氯化蒸馏废酸还原回收锗

以锗烟尘氯化蒸馏后的废盐酸为原料,以废铁为还原剂,使废酸中的有价金属锗以还原态沉淀富集在渣中,强化氧化氯化蒸馏回收四氯化锗,锗的综合回收率达94．10％。同时生产净水剂用液体氯化铁产品。     

Development of a novel myconanomining approach for the recovery of agriculturally important elements from jarosite waste

In this study, an ecofriendly and economically viable waste management approach have been attempted towards the biosynthesis of agriculturally important nanoparticles from jarosite waste. Aspergillus terreus strain J4 isolated from jarosite(waste from Debari Zinc Smelter,Udaipur, India), showed good leaching efficiency along with nanoparticles(NPs) formation under ambient conditions. Fourier-transform infrared spectroscopy(FT-IR) and transmission electron microscopy(TEM) confirmed the formation of NPs. Energy dispersive X-ray spectroscopy(EDX analysis) showed strong signals for zinc, iron, calcium and magnesium,with these materials being leached out. TEM analysis and high resolution transmission electron microscopy(HRTEM) showed semi-quasi spherical particles having average size of 10‐50 nm. Thus, a novel biomethodology was developed using fungal cell-free extract for bioleaching and subsequently nanoconversion of the waste materials into nanostructured form. These biosynthesized nanoparticles were tested for their efficacy on seed emergence activity of wheat(Triticum aestivum) seeds and showed enhanced growth at concentration of 20 ppm. These nanomaterials are expected to enhance plant growth properties and being targeted as additives in soil fertility and crop productivity enhancement.     

中国铝生命周期能耗与碳排放的情景分析及减排对策

铝工业是高能耗高排放工业,探索铝工业的节能减排路径有助于我国实现《巴黎协定》中的温室气体减排承诺.采用物质流分析和生命周期评价方法,基于存量水平、技术水平和能源结构设置了15种情景,研究了我国铝工业1990～2100年的能耗和碳排放量,探索不同路径下的节能减排潜力.我国铝在用存量将在2040～2050年达到峰值(4.6...     

Development of a high-resolution spatial inventory of greenhouse gas emissions for Poland from stationary and mobile sources

Greenhouse gas (GHG) inventories at national or provincial levels include the total emissions as well as the emissions for many categories of human activity, but there is a need for spatially explicit GHG emission inventories. Hence, the aim of this research was to outline a methodology for producing a high-resolution spatially explicit emission inventory, demonstrated for Poland. GHG emission sources were classified into point, line, and area types and then combined to calculate the total emissions. We created vector maps of all sources for all categories of economic activity covered by the IPCC guidelines, using official information about companies, the administrative maps, Corine Land Cover, and other available data. We created the algorithms for the disaggregation of these data to the level of elementary objects such as emission sources. The algorithms used depend on the categories of economic activity under investigation. We calculated the emissions of carbon, nitrogen sulfure and other GHG compounds (e.g., CO₂, CH₄, N₂O, SO₂, NMVOC) as well as total emissions in the CO₂-equivalent. Gridded data were only created in the final stage to present the summarized emissions of very diverse sources from all categories. In our approach, information on the administrative assignment of corresponding emission sources is retained, which makes it possible to aggregate the final results to different administrative levels including municipalities, which is not possible using a traditional gridded emission approach. We demonstrate that any grid size can be chosen to match the aim of the spatial inventory, but not less than 100 m in this example, which corresponds to the coarsest resolution of the input datasets. We then considered the uncertainties in the statistical data, the calorific values, and the emission factors, with symmetric and asymmetric (lognormal) distributions. Using the Monte Carlo method, uncertainties, expressed using 95% confidence intervals, were estimated for high point-type emission sources, the provinces, and the subsectors. Such an approach is flexible, provided the data are available, and can be applied to other countries.

     

An evaluation of mercury emissions from the chlor-alkali industry in China

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Air pollutant emissions from the asphalt industry in Beijing, China

Improving our understanding of air pollutant emissions from the asphalt industry is critical for the development and implementation of pollution control policies. In this study, the spatial distribution of potential maximum emissions of volatile organic compounds (VOCs) in the complete life cycle of asphalt mixtures, as well as the particulate matter (PM), asphalt fume, nonmethane hydrocarbons (NMHCs), VOCs, and benzoapyrene (BaP) emissions from typical processes (e.g., asphalt and concrete mixing stations, asphalt heating boilers, and asphalt storage tanks) in asphalt mixing plants, were determined in Beijing in 2017. The results indicated that the potential maximum emissions of VOCs in the complete life cycle of asphalt mixtures were 18,001 ton, with a large contribution from the districts of Daxing, Changping, and Tongzhou. The total emissions of PM, asphalt fume, NMHC, VOCs, and BaP from asphalt mixing plants were 3.1, 12.6, 3.1, 23.5, and 1.9 × 10^?3 ton, respectively. The emissions of PM from asphalt and concrete mixing stations contributed the most to the total emissions. The asphalt storage tank was the dominant emission source of VOCs, accounting for 96.1% of the total VOCs emissions in asphalt mixing plants, followed by asphalt heating boilers. The districts of Daxing, Changping, and Shunyi were the dominant regions for the emissions of PM, asphalt fume, NMHC, and BaP, while the districts of Shunyi, Tongzhou, and Changping contributed the most emissions of VOCs.     

Process modification in the scouring process of textile industry

The effects of scouring parameters on the scouring efficiency, including the weight ratio of de-sizing agent and fabric (5–80 g/g fabric), temperature of de-sizing agent tank (60–90 °C) and dipping time (2–8 s), were investigated. The results demonstrated that weight loss of sizing agent was significantly observed only in the de-sizing agent tank particularly in the first de-sizing tank and was found to a small extent in water tank. The optimum condition in the scouring machine was found at a de-sizing agent to fabric ratio of 20 g/g fabric, with a temperature of the first de-sizing agent tank of 80 °C, a temperature of the second de-sizing agent tank of 90 °C, and dipping time of fabric of 7 s. According to these conditions, more than 89% of the sizing agent was eliminated and only 3.52 mg/g fabric of sizing agent remained in the scoured fabric which was in an acceptable range for feeding to the down stream process known as dyeing process. Application of our results to actual textile plant has shown that there is a cost reduction due to improved utilization of rinse water, chemicals and energy in the process and consequent decreases in the generation of wastewater. Furthermore, the production capacity was increased from 30 m/min to 34.4 m/min.     

Technological options for waste minimisation in the mining industry

Just as the application of technology in mining processes can cause pollution, it can also be harnessed to minimise, and sometimes eliminate, mine-related contaminants. Waste minimisation can be achieved through decreased waste production, waste collection, waste recycling, and the neutralisation of pollutants into detoxified forms. This article reviews examples of how technology can be used to minimise air, water, land and noise pollution in the mining industry.     

我国生活垃圾焚烧发电过程中温室气体排放及影响因素 ——以上海某城市生活垃圾焚烧发电厂为例

以上海某城市生活垃圾焚烧发电厂为例,采用上游-操作-下游(UOD)表格法,分析了生活垃圾焚烧发电过程中不同环节的温室气体排放贡献,及影响其排放的主要因素.结果表明,目前我国生活垃圾焚烧发电过程是温室气体排放源,以吨垃圾净CO2排放量计,达166~212kg.生活垃圾中自含化石碳对温室气体排放的贡献最大,CO2排放量为257kg/t;因焚烧发电上网而获得的净减排量为120kg/t;垃圾收运、辅助物料消耗及焚烧灰渣处理等引起的排放量总计为27~45kg/t.生活垃圾沥出渗滤液后续处理过程的温室气体排放量为7.7kg/t.节省焚烧过程辅助物料使用和改变焚烧灰渣处置方式能够减少温室气体排放量,但是减排效果有限.我国各地区电能基准线排放因子存在差异,对焚烧过程温室气体排放的影响为0~13%.降低生活垃圾含水率、提高垃圾可发电量是我国生活垃圾焚烧发电过程温室气体排放源汇转换的关键途径.     

The local deposition of heavy metal emissions from point sources in Antarctica

Surface snow samples have been analysed for the heavy metals Cd, Cu, Pb and Zn to investigate the spatial scale of local sources of pollution in Antarctica. Samples from around an isolated petrol generator showed vastly increased levels (up to 800,000 times background) directly under the exhaust. Concentrations fell sharply with distance from the exhaust, reaching background levels at 40 m, even in the downwind direction. Snow was also collected at various distances from a manned scientific station. The data are more difficult to interpret, but the influence of the station could not be detected beyond 10 km. These findings indicate the areas that are influenced by local emissions, and that are therefore unsuitable for air and snow sampling intended to study larger-scale pollution input.     

Allocation of GHG emissions in combined heat and power systems: a new proposal for considering inefficiencies of the system

The paper industry is responsible for a considerable amount of greenhouse gas (GHG) emissions mainly due to its intensive energy requirements. The production of heat and power streams in a cogeneration system, i.e., a combined heat and power (CHP) plant, releases considerable amounts of GHG emissions into the atmosphere. Such emissions are already subjected to legislation globally. The amount of GHG emissions is usually calculated from the product of the total amount of energy activity multiplied by an emission factor. However, each energy output stream should get a share of emissions responsibility. This fact could assist in assigning weights to the emissions generated for power and thermal purposes in a combined heat and power plant. However, developing a suitable method of allocating emissions in a cogeneration system is still a concern and a subject research for scientists, companies and policy makers. This paper exposes and evaluates different published allocation methods and applies them to a real case of a combined heat and power plant integrated in a paper mill and proposes a new allocation method.     

Effects of introducing energy recovery processes to the municipal solid waste management system in Ulaanbaatar,Mongolia

Currently, most developing countries have not set up municipal solid waste management systems with a view of recovering energy from waste or reducing greenhouse gas emissions. In this article, we have studied the possible effects of introducing three energy recovery processes either as a single or combination approach, refuse derived fuel production, incineration and waste power generation, and methane gas recovery from landfill and power generation in Ulaanbaatar, Mongolia, as a case study. We concluded that incineration process is the most suitable as first introduction of energy recovery. To operate it efficiently, 3Rs strategies need to be promoted. And then, RDF production which is made of waste papers and plastics in high level of sorting may be considered as the second step of energy recovery. However, safety control and marketability of RDF will be required at that moment.     

Effects of introducing energy recovery processes to the municipal solid waste management system in Ulaanbaatar,Mongolia

Currently, most developing countries have not set up municipal solid waste management systems with a view of recovering energy from waste or reducing greenhouse gas emissions. In this article, we have studied the possible effects of introducing three energy recovery processes either as a single or combination approach, refuse derived fuel production,incineration and waste power generation, and methane gas recovery from landfill and power generation in Ulaanbaatar, Mongolia, as a case study. We concluded that incineration process is the most suitable as first introduction of energy recovery. To operate it efficiently,3Rs strategies need to be promoted. And then, RDF production which is made of waste papers and plastics in high level of sorting may be considered as the second step of energy recovery.However, safety control and marketability of RDF will be required at that moment.