漆渣的循环再利用

漆渣是喷漆过程产生的废弃物,2013年中国仅汽车行业就产生漆渣约6.64万t。由于漆渣的巨大产生量和有害属性,对处理和处置造成很大挑战。循环和再利用是废弃物处置方法中对环境最友好的解决方式。从水泥窑协同处置、热干燥处理及产物利用、热解处理及产物利用三方面,回顾了近20年来在漆渣循环再用方面的研究进展和实际应用。     

固体废弃物在家具产品中的再生利用探析

从家具行业可持续发展角度出发,结合国内外经典案例,阐述了国内家具设计中对固体废弃物利用不足的现状,并从政策、企业、设计者和消费者4个角度,对固体废弃物在家具产品中的再生利用提出建议。     

Accelerated carbonation treatment of industrial wastes

The disposal of industrial waste presents major logistical, financial and environmental issues. Technologies that can reduce the hazardous properties of wastes are urgently required. In the present work, a number of industrial wastes arising from the cement, metallurgical, paper, waste disposal and energy industries were treated with accelerated carbonation. In this process carbonation was effected by exposing the waste to pure carbon dioxide gas. The paper and cement wastes chemically combined with up to 25% by weight of gas. The reactivity of the wastes to carbon dioxide was controlled by their constituent minerals, and not by their elemental composition, as previously postulated. Similarly, microstructural alteration upon carbonation was primarily influenced by mineralogy. Many of the thermal wastes tested were classified as hazardous, based upon regulated metal content and pH. Treatment by accelerated carbonation reduced the leaching of certain metals, aiding the disposal of many as stable non-reactive wastes. Significant volumes of carbon dioxide were sequestrated into the accelerated carbonated treated wastes.     

工业固体废物资源化的思考

循环经济发展模式从根本上缓解环境、资源与发展之间的尖锐冲突,在促进经济增长的同时顾及到生态环境的承受能力,从工业经济系统自身发掘资源、能源,充分挖掘潜力,寻找伴生资源,开发利用废弃物,促进工业固体废物资源化,以循环经济模式替代陈旧的线性经济模式,保持经济可持续发展。     

Recycling rates of waste home appliances in Taiwan

The objective of this study is to provide a calculation of recycling rates of waste home appliances in Taiwan, for the EPA to amend these rates in order to increase the recycling efficiency. The recycling rate is calculated by a formula according to the statistical results obtained through: (1) an estimation of domestic use of home appliances using time series analysis with multiplicative seasonal ARIMA model, (2) a further estimation of generated waste home appliances based upon the estimated domestic use and the corresponding distribution of lifetime span, and (3) a cost analysis of recycling home appliances based on a sampling survey with stratified systematic sampling conducted among collectors and a survey on five recycling plants of waste home appliances. The suggested recycling rates in this study finally used by the EPA show that all of the recycling rates have increased compared with the rates in previous years. This study also implies that amending the recycling rates may only solve some recycling problems temporarily; however, the recycling system of waste home appliances in Taiwan has to be reformed to increase the recycling efficiency for the long term.     

Recapitulating potential environmental and industrial applications of biomass wastes

Journal of Material Cycles and Waste Management - The generation of biomass wastes is a huge concern as they have to be properly managed to ensure environmental wellbeing. This article examined...     

Circulating fluidized bed incineration of industrial solid wastes

A pilot scale test facility of a circulating fluidized bed incinerator was established to generate design and operation data and help assess the technical feasibility for industrial applications. The use of high turbulence in the combustion zone and feeding an acid-capturer directly into the incinerator to absorb acid gases eliminates the costly afterburner and scrubber. This paper presents some systematic incineration tests of uniform industrial wastes such as paper mill sludge cake, rubber waste and petroleum coke. Sludge cakes with high moisture and low heating values can be treated to a low emission level by co-firing with coal. The high superficial gas velocity has improved combustion efficiency but increases NO_x emissions. However, sulphur content has almost no influence on sulphur retention. The problems of CO/NO_x emissions and circulation stability are also discussed.     

Characteristics and management of infectious industrial waste in Taiwan

Infectious industrial waste management in Taiwan is based on the specific waste production unit. In other countries, management is based simply on whether the producer may lead to infectious disease. Thus, Taiwan has a more detailed classification of infectious waste. The advantage of this classification is that it is easy to identify the sources, while the disadvantage lies in the fact that it is not flexible and hence increases cost. This study presents an overview of current management practices for handling infectious industrial waste in Taiwan, and addresses the current waste disposal methods. The number of small clinics in Taiwan increased from 18,183 to 18,877 between 2003 and 2005. Analysis of the data between 2003 and 2005 showed that the majority of medical waste was general industrial waste, which accounted for 76.9%-79.4% of total medical waste. Infectious industrial waste accounted for 19.3%-21.9% of total medical waste. After the SARS event in Taiwan, the amount of infectious waste reached 19,350 tons in 2004, an increase over the previous year of 4000 tons. Waste minimization was a common consideration for all types of waste treatment. In this study, we summarize the percentage of plastic waste in flammable infectious industrial waste generated by medical units, which, in Taiwan was about 30%. The EPA and Taiwan Department of Health have actively promoted different recycling and waste reduction measures. However, the wide adoption of disposable materials made recycling and waste reduction difficult for some hospitals. It has been suggested that enhancing the education of and promoting communication between medical units and recycling industries must be implemented to prevent recyclable waste from entering the incinerator.     

Electronic tracking and management of industrial waste in Taiwan

This study discusses an online reporting system used for waste flow tracking (auditing) and investigation of violations. In contrast to systems used in other countries, this system requires waste generators and transporters, as well as the treatment, storage, and disposal facilities (TSDFs) to file online reports on the movement of industrial waste within 24 h of being shipped, received, or completely treated. This system also provides online analytical processing for reporters to analyze all their data, thereby encouraging self-management of waste. Currently there are 25,861 generators, 4,963 transporters, and 865 TSDFs in Taiwan that are required to file online reports. Approximately 80 % of all waste generated in Taiwan is reported using this system. More than 7,000 vehicles are equipped with a global positioning system (GPS) for waste tracking, among which over 2,000 transport hazardous waste. Disposal vehicles transmit their locations to the Control Center every 30 s. Database quality has been enhanced through auditing and inspection for more than 12 years since this system was established. It serves as a “single portal” for industrial waste management and facilitates informed decision making for resource exchange and material flow among various industries to achieve resource and environmental sustainability.     

Recycling of extruded polystyrene wastes by dissolution and supercritical CO2 technology

Polystyrene (PS) is currently used as packaging, insulating and storing material in various industrial or domestic fields. As a result, a large quantity of PS wastes is produced. Plastic wastes are not usually biodegradable, so it is necessary to suggest a technology to recycle them. Landfills and incineration are reasonably cheap methods but are not environmentally acceptable, therefore, alternative methods for polymer recycling are required. The general purpose of PS foam recycling is to recover a more compact polymeric material without degradation. Dissolution with terpenic solvents is presented here as an efficient and cheap alternative that is developed at room temperature; among the oils studied, limonene was selected because of its intermediate solubility and its abundance. The solvent removal is possible thanks to supercritical technology that provides a high solubility in limonene and almost a complete PS insolubility at moderated pressures (77?bar) and low temperatures (30?°C). Thus, based on the results of thermogravimetric and chromatographic analysis, we propose that.supercritical antisolvent precipitation is an ideal technique for carrying out the separation of PS and limonene, providing a recycled polymer with a reduced volume, almost completely free of solvent and without degradation of the polymeric chains.     

Recycling and reuse of waste from electricity distribution networks as reinforcement agents in polymeric composites

Of the waste generated from electricity distribution networks, wooden posts treated with chromated copper arsenate (CCA) and ceramic insulators make up the majority of the materials for which no effective recycling scheme has been developed. This study aims to recycle and reuse this waste as reinforcement elements in polymer composites and hybrid composites, promoting an ecologically and economically viable alternative for the disposal of this waste. The CCA wooden posts were cut, crushed and recycled via acid leaching using 0.2 and 0.4 N H₂SO₄ in triplicate at 70 °C and then washed and dried. The ceramic insulators were fragmented in a hydraulic press and separated by particle size using a vibrating sieve. The composites were mixed in a twin-screw extruder and injected into the test specimens, which were subjected to physical, mechanical, thermal and morphological characterization. The results indicate that the acid treatment most effective for removing heavy metals in the wood utilizes 0.4 N H₂SO₄. However, the composites made from wood treated with 0.2 N H₂SO₄ exhibited the highest mechanical properties of the composites, whereas the use of a ceramic insulator produces composites with better thermal stability and impact strength. This study is part of the research and development project of ANEEL (Agência Nacional de Energia Elétrica) and funded by CPFL (Companhia Paulista de Força e Luz).     

Recycling tannery solid wastes as an alternative carbon resource for ironmaking

Journal of Material Cycles and Waste Management - Tanneries are well-known for generating a huge amount of solid wastes and it is crucial to develop novel environmentally sustainable technologies...     

Chemical durability of glasses obtained by vitrification of industrial wastes

The vitrification of zinc-hydrometallurgy wastes, electric arc furnace dust (EAFD), drainage mud, and granite mud was shown to immobilize the hazardous components in these wastes. Batch compositions were prepared by mixing the wastes with glass-cullet and sand to force the final glass composition into the glass forming region of the SiO2-Fe2O3-(CaO, MgO) system. The vitrification was carried out in the 1400-1450 degrees C temperature range followed by quenching in water or on stainless steel mold. The United States (US) Environmental Protection Agency (EPA) toxic characterization leaching procedure (TCLP) test was used as a standard method for evaluating the leachability of the elements in the glasses and glass-ceramics samples made with different percentages of wastes. The results for EAFD glasses highlighted that the chemical stability is influenced by the glass structure formed, which, in turn, depends on the Si/O ratio in the glass. The chemical durability of jarosite glasses and glass-ceramics was evaluated by 24 h contact in NaOH, HCl and Na2CO3, at 95 degrees C. Jarosite glass-ceramics containing pyroxene (J40) are more durable than the parent glass in HCl. Jarosite glass-ceramics containing magnetite type spinels (J50) have a durability similar to the parent glass and even lower in HCl because the magnetite is soluble in HCl.     

Bioconversion of industrial wastes: paint sludge from automotive manufacturing

The compostability of water-based paint sludge originating from the automotive industry was investigated. Six reactors were operated. Wastewater treatment sludge from the same industry was used as additional substrate, and corncob was used as a bulking agent. The level of paint sludge within the compost mixtures varied between 55 and 85%. All reactors yielded a temperature increase up to thermophilic phase levels (>?40 °C) for a minimum of 5 days, and organic matter and C/N losses were observed. BTEX concentrations decreased during composting. Nickel and tin levels in the final product exceeded the legal compost limits. The calorific value of the compost mixtures increased from 9532 to 18774 kJ/kg at the end of the composting process. It was seen that the process applied in this study can be utilized as a biodrying step before the usage of paint sludge at cement kilns as additional fuel.     

Recycling of organic wastes in burnt soils: combined application of poultry manure and plant cultivation

A pot experiment was conducted to investigate the efficacy of a post-fire land management practice, including plant cultivation (Lolium perenne) combined with poultry manure addition, for restoring the protective vegetation cover in soils degraded by high intensity wildfires. The greenhouse experiment was performed with three burnt pine forest soils with added poultry manure at two doses of application and comparing the data with those obtained using NPK fertilizer. A significant effect of the amendment, soil properties and the interaction between amendment and soil properties on vegetation cover (phytomass production, nutrient content) was detected, but often the amendment treatment explained most of the variance. Changes induced by the organic amendment were more marked than those induced by inorganic fertilization. The increase of phytomass and nutrient uptake with poultry manure addition indicated the beneficial effects of this soil management practice. These findings can serve to develop field experiments and burnt soils reclamation technology.     

Solid industrial wastes and their management in Asegra (Granada, Spain)

ASEGRA is an industrial area in Granada (Spain) with important waste management problems. In order to properly manage and control waste production in industry, one must know the quantity, type, and composition of industrial wastes, as well as the management practices of the companies involved. In our study, questionnaires were used to collect data regarding methods of waste management used in 170 of the 230 businesses in the area of study. The majority of these companies in ASEGRA are small or medium-size, and belong to the service sector, transport, and distribution. This was naturally a conditioning factor in both the type and management of the wastes generated. It was observed that paper and cardboard, plastic, wood, and metals were the most common types of waste, mainly generated from packaging (49% of the total volume), as well as material used in containers and for wrapping products. Serious problems were observed in the management of these wastes. In most cases they were disposed of by dumping, and very rarely did businesses resort to reuse, recycling or valorization. Smaller companies encountered greater difficulties when it came to effective waste management. The most frequent solution for the disposal of wastes in the area was dumping.     

Prediction of unconfined compressive strength of cement paste containing industrial wastes

Neural network analysis was used to construct models of unconfined compressive strength (UCS) as a function of mix composition using existing data from literature studies of Portland cement containing real industrial wastes. The models were able to represent the known non-linear dependency of UCS on curing time and water content, and generalised from the literature data to find relationships between UCS and quantities of five waste types. Substantial decreases in UCS were caused by all wastes; except for EAF dust, the effect was nonlinear with the greatest decrease caused initially by approx. 12% plating sludge, 40% foundry dust, 58% other ash, and 72% MSWI fly ash by mass of dry product. It appears that the maximum waste additions used in modelling may approximate the practical limits of waste additions used in modelling may approximate the practical limits of waste addition to Portland cement, i.e., 50% plating sludge or EAF dust, 64% foundry dust, 92% other ash, and 85% MSWI fly ash by mass of dry product. The laboratory was found to be a key predictive variable and acted as a surrogate for laboratory-specific variables related to cement composition, strength and hardening class, product mixing and preparation details, laboratory conditions, and testing details. While the neural network modelling approach has been shown to be feasible, development of better models would require larger data sets with more complete information regarding laboratory-specific variables and waste composition.     

Vitrification of lead-rich solid ashes from incineration of hazardous industrial wastes

Lead-rich solid industrial wastes were vitrified by the addition of glass formers in various concentrations, to produce non-toxic vitreous stabilized products that can be freely disposed or used as construction materials. Toxicity of both the as-received industrial solid waste and the stabilized products was determined using standard leaching test procedures. The chemically stable vitreous products were subjected to thermal annealing in order to investigate the extent of crystal separation that could occur during cooling of large pieces of glass. Leaching tests were repeated to investigate the relation between annealing process and chemical stability. X-ray, scanning and transmission electron microscopy techniques were employed to identify the microstructure of stabilized products before and after thermal treatment. Relation between synthesis and processing, chemical stability and microstructure was investigated.