Showing papers in "Resources Conservation and Recycling in 2010"

Recycling utilization patterns of coal mining waste in China

Abstract: With the fast development of Chinese economy in recent years, China has become the largest coal production and consumption country in the world. Correspondingly, it has produced large quantities of mining waste including coal gangue, coal sludge, fly-ash, coal mine drainage and coal-bed methane (CBM) that are hazardous to the soil, air, and water. Based on the theory and practice of sustainable development and recycling economy, the paper will discuss and analyze the mining waste management in Jincheng Anthracite Mining Group, Shanxi Province, where they have found the paths to realize the mining waste reusing and recycling in colliery. They had established many green industrial chains in the mining waste treatment: the gangue piles turned into man-made eco-park, gangue used for power generation, fly-ash used in the building material, the coal mining water reused and recycled in closed pipelines, the CBM extracted for home-burning and electricity generation, etc. The coal mining waste has been converted into wealth and played more and more important roles in many fields. The practice indicated that these patterns can be applied in other coal mines.

Green product purchase intention: Some insights from a developing country

Abstract: This paper examines from the motivational perspective of the Theory of Reasoned Action (TRA) how individual values and attitudes in a developing country influence purchase intention of a green product. It also investigates how values may affect attitudes towards environmentally responsible purchase intention. The study analyzed data collected from 257 working respondents who were asked their views concerning their value sets, attitudes and purchase intention of cloth diapers using the Structural Equation Modeling (SEM) technique. Findings indicate individual consequences relating to amount of effort and convenience of consumers is negatively related to intention to purchase green product. Environmental consequences are not a significant predictor of environmentally responsible purchase intention. Conservation value was found to be positively related to attitude on environmental consequences but less intensely with individual consequences while both self-transcendence value and self-enhancement value were positively related to individual consequences. Individual consequences and self-enhancement value were negatively related to environmentally responsible purchase intention. This paper has shown that the extended TRA is applicable and also this paper has enhanced understanding of predictors of environmentally responsible purchase intention in a developing country context.

LCA allocation procedure used as an incitative method for waste recycling: An application to mineral additions in concrete

Abstract: Waste recycling avoids waste landfilling and all associated releases. It also allows for saving nonrenewable resources. However, the new commercial interest for waste can be seen as a shift in their status from waste to co-product. This has important consequences for environmental load allocation between the different industrial products (and co-products) in industrial plants. In this paper, the specific case of cement has been studied. Actually, to reduce the environmental impact of cement and concrete, industries have been engaged over the last 10 years to increase the replacement of Portland cement by alternative cementitious materials that are principally industrial waste or by-products. In this study, the environmental impacts of two different Supplementary Cementitious Materials (SCM), blast furnace slag and fly ash, are considered using Life Cycle Assessment methodology through a study of the influence of different allocation procedures on environmental impacts of SCM in concrete. Three allocation procedures are tested. In the first one, which is the current practice, no allocations are done. As for the two others, the environmental burdens of the system are respectively associated with the relative mass and some current economic values of the co-products and products. The results are discussed according to the specificity of the cement substitution products (SCM) and the driving forces that are identified for the use of these co-products. Then, a description investigation of another allocation procedure is proposed based on the fact that it is not the relative economic value that permits to evaluate the environmental burdens but the contrary. This last allocation procedure could be generalised for other waste recycling and be used as a regulation tool between the different industrial branches.

The effects of behavior and attitudes on drop-off recycling activities

Abstract: To reduce the amount of waste entering landfills, policymakers and governments have implemented various recycling and waste reduction programs such as source reduction, curbside recycling and drop-off recycling programs. The success of a recycling program largely depends on household participation and sorting activities. A better understanding of recycling behavior will help us aid the design and improve the effectiveness of recycling policies. This paper studies the profile of people who utilize drop-off recycling sites and analyzes the factors influencing their site usage. The results show that the usage of drop-off recycling sites is influenced by demographic factors such as age, education, income and household size. Attitudinal factors are also found to affect site usage. Recyclers tend to use the drop-off sites more when they feel that recycling is a convenient activity and when they are more familiar with the sites.

Open-loop recycling: A LCA case study of PET bottle-to-fibre recycling

Abstract: This study assesses the environmental impact of polyethylene terephthalate (PET) bottle-to-fibre recycling using the methodology of life-cycle assessment (LCA). Four recycling cases, including mechanical recycling, semi-mechanical recycling, back-to-oligomer recycling and back-to-monomer recycling were analysed. Three allocation methods are applied for open-loop recycling, i.e. the “cut-off” approach, the “waste valuation” approach and the “system expansion” approach. Nine environmental impact indicators were analysed, i.e. non-renewable energy use (NREU), global warming potential (GWP), abiotic depletion, acidification, eutrophication, human toxicity, fresh water aquatic ecotoxicity, terrestrial ecotoxicity and photochemical oxidant formation. The LCA results are compared with virgin PET fibre and other commodity fibre products, i.e. cotton, viscose, PP (polypropylene) and PLA (polylactic acid). The LCA results show that recycled PET fibres offer important environmental benefits over virgin PET fibre. Depending on the allocation methods applied for open-loop-recycling, NREU savings of 40–85% and GWP savings of 25–75% can be achieved. Recycled PET fibres produced by mechanical recycling cause lower environmental impacts than virgin PET in at least eight out of a total of nine categories. Recycled fibres produced from chemical recycling allow to reduce impacts in six to seven out of a total of nine categories compared to virgin PET fibres. Note that while mechanical recycling has a better environmental profile than chemical recycling, chemically recycled fibres can be applied in a wider range of applications than mechanically recycled fibres.

Plastic waste management in the context of a European recycling society: Comparing results and uncertainties in a life cycle perspective

Abstract: A number of life cycle assessment (LCA) studies have been undertaken within the last 15 years comparing end-of-life treatment options for post-consumer plastic waste, including techniques such as: ...

Recycling rechargeable lithium ion batteries: Critical analysis of natural resource savings

Abstract: Rechargeable Li-ion battery applications in consumer products are fastly growing, resulting in increasing resources demand: it is for example estimated that battery applications account for nearly 25% of the worldwide cobalt demand in 2007. It is obvious that recycling of batteries may help saving natural resources. However, it is not straightforward to quantify to what extent rechargeable battery recycling saves natural resources, given their complex composition, and the complex international production chain. In this paper, a detailed analysis of a lithium mixed metal oxide battery recycling scenario, where cobalt and nickel are recovered and re-introduced into the battery production chain, is compared with a virgin production scenario. Based on detailed data acquisition from processes spread worldwide, a resource saving analysis is made. The savings are quantified in terms of exergy and cumulative exergy extracted from the natural environment. It turns out that the recycling scenario result in a 51.3% natural resource savings, not only because of decreased mineral ore dependency but also because of reduced fossil resource (45.3% reduction) and nuclear energy demand (57.2%).

Evaluation of the economic feasibility for the recycling of construction and demolition waste in China—The case of Chongqing

Abstract: In the recycling chain of construction and demolition waste, it is impossible to guarantee a certain quality of recycled products and to recycle a large amount of materials in recycling centers without mechanical sorting facilities. This counts even more when the produced materials have a low economic value, as is the case with crushed and cleaned debris, also called aggregates. In order to assess if recycling can be done effectively, a feasibility study of the recycling of construction and demolition (C&D) waste is necessary. In the paper, the economic feasibility of recycling facilities for C&D waste in China's Chongqing city was assessed. Investigations on the current situation of C&D waste recycling in Chongqing showed that there were a large quantity of waste and an enormous demand for recycled materials due to the busy ongoing construction activities, which generated a large market potential and also brought a challenge to the strengthening of the recycling sector. However, a full cost calculation and an investment analysis showed that, under current market conditions, operating C&D waste recycling centers in Chongqing might face high investment risks. Thus, the regulations and economic instruments like tax that can support the economic feasibility of recycling are discussed, and the recommendations for the choice of instruments are provided.

Critical success factors for on-site sorting of construction waste: A china study

Abstract: Benefits of conducting on-site sorting of construction waste, typically including increasing the rates of reuse and recycling, reducing the cost for waste transportation and disposal, prolonging the lifespan of landfills designed for receiving non-inert construction waste, and lessening the pollution resulted from the huge amount of construction waste, have been extensively investigated by previous studies. However, effective implementation of construction waste sorting requires a wide range of factors involving human beings, management, technology, environment and resources. So far, we know little about how to conduct effective construction waste sorting in China. This research therefore aims to identify the critical success factors (CSFs) for on-site sorting of construction waste in China. A set of methods including CSF approach, pilot study, questionnaire survey and face-to-face interview are adopted to facilitate the identification and analysis of the CSFs. Six factors including (1) manpower, (2) market for recycled materials, (3) waste sortability, (4) better management, (5) site space, (6) equipment for sorting of construction waste, are considered the CSFs for effective on-site sorting of construction waste in Shenzhen, China. These CSFs are of great significance both to researchers and industry practitioners.

Factors influencing the rate of recycling: An analysis of Minnesota counties

Abstract: This study analyzes the effects of various recycling and waste management policy variables on recycling rate by utilizing county-level panel data from Minnesota covering the period 1996–2004. The policy variables examined include variable pricing for waste disposal, expenditure on recycling education, provision of curbside recycling services and drop-off centers, and enactment of recycling ordinances. Unlike previous studies, this study accounts for the cumulative effects of the expenditure variable on recycling rate and also investigates whether different recycling programs such as curbside and drop-off recycling act as complements or substitutes in increasing recycling rates. This study also examines the effect of income and demographic characteristics on recycling rate. After accounting for random effects and endogenous variables, the results indicate that variable pricing of waste disposal increases the rate of recycling. Other policy variables such as the enactment of recycling ordinances and cumulative expenditures on recycling education are also found to be effective measures to increase recycling rate.

Performance of rainwater harvesting systems in the southeastern United States

Abstract: Recent severe droughts, concerns over the environmental impact of stormwater runoff and increased water demands have generated interest in rainwater harvesting systems in humid, well developed regions, such as the southeastern United States. In order to evaluate the use of rainwater harvesting systems in this region, a monitoring study was conducted at three rainwater cisterns in North Carolina, a computer model was developed to simulate system performance, and simulations were conducted for 208 l rain barrels and larger cisterns. Results of the monitoring study showed that the rainwater harvesting systems were underutilized, which was suspected to result from poor estimation of water usage and public perception of the harvested rainwater. The computer model simulated system performance by evaluating a water balance using historical rainfall data and anticipated usage. Simulation results showed that a rain barrel was frequently depleted when used to meet household irrigation demands and overflowed during most rainfall events. Simulations also illustrated the improved performance of large systems while providing an indication of diminishing returns for increased cistern capacity.

Managing e-waste in China: Policies, pilot projects and alternative approaches

Abstract: As the largest exporter of electrical and electronic equipment (EEE) and importer of waste electrical and electronic equipment (WEEE, also called e-waste) around the world, China plays a key role in the global life cycle of electronics. This paper reviews the existing framework for e-waste management in China including regulatory policies and pilot projects. The Chinese government has been active in creating a legislative and institutional framework to realize e-waste recycling. Pilot projects have been established with the intent to test new formal systems to replace informal recycling. These projects have usually failed to collect sufficient e-waste, mainly because informal recyclers pay consumers for their e-waste and pilot projects do not. Challenges to implementing e-waste reuse/recycling systems particular to the Chinese situation are analyzed and two alternative policy approaches are proposed to deal with these challenges. The first policy approach proposed is a system which shares financial responsibility among consumers, manufacturers and the government. The system includes a deposit returned to consumers as an incentive to turn in e-waste. The second proposal is, where appropriate, to include an e-waste channel which mixes informal and formal sectors, with the informal sector handling collection and reuse and the formal sector responsible for dismantling and recycling.

Reducing solid waste in higher education: The first step towards ‘greening’ a university campus

Abstract: Comprehensive solid waste management programs are one of the greatest challenges to achieving campus sustainability. Conducting a waste characterization study is a critical first step in successful waste management planning and advancing the overall sustainability of an institution of higher education. This paper reports on a waste characterization study that was conducted at the Prince George campus of the University of Northern British Columbia (UNBC). The aim of the study was to determine the amount and composition of waste generated within key campus operational areas and to provide recommendations to senior university administration on strategies for waste minimization, higher rates of recycling and composting and improving the overall sustainability of the campus waste management program. It was determined that during the 2007–2008 academic year the Prince George campus produced between 1.2 and 2.2 metric tonnes of waste per week, of which more than 70% could have been diverted through waste reduction, recycling and composting activities. Paper and paper products, disposable drink containers and compostable organic material represented three of the most significant material types for targeted waste reduction and recycling efforts. Various educational and policy techniques, which may be used to promote campus community waste minimization behaviours in the long term, are discussed.

Exploring critical success factors for waste management in construction projects of China

Abstract: The enormous amount of construction activity in China associated with its rapid economic development has produced a large amount of construction and demolition (C&D) waste over the past three decades. The majority of this waste has not been well processed, which has led to severe damage to the environment. Although there is clearly a need for better C&D waste management (WM) in China, the best ways to achieve this have yet to be fully explored. This paper is based on a study by the authors that aimed to identify the Critical Success Factors (CSFs) for C&D WM in China. A questionnaire survey and 14 semi-structured interviews with practitioners, researchers and government officials were conducted in Shenzhen, a leading city in southern China for tackling C&D WM. Seven factors were identified as the CSFs for managing C&D waste: (1) WM regulations, (2) waste management system (WMS), (3) awareness of C&D WM, (4) low-waste building technologies, (5) fewer design changes, (6) research and development in WM, and (7) vocational training in WM. These CSFs can serve as valuable references for stakeholders to develop effective C&D WM strategies. The research also adds to the knowledge on how to reduce adverse environmental impacts caused by construction activities in rapidly developing economies.

Modeling and optimization of biogas production from a waste digester using artificial neural network and genetic algorithm

Abstract: Artificial neural networks (ANNs) and genetic algorithms (GA) are considered among the latest tools that are used to solve complicated problems that cannot be solved by conventional solutions. The present study utilizes the ANN and GA as tools for simulating and optimizing of biogas production process from the digester of Russaifah biogas plant in Jordan. Operational data of the plant for a period of 177 days were collected and employed in the analysis. The study considered the effect of digester operational parameters, such as temperature (T), total solids (TS), total volatile solids (TVS), and pH on the biogas yield. A multi-layer ANN model with two hidden layers was trained to simulate the digester operation and to predict the methane production. The performance of the ANN model is verified and demonstrated the effectiveness of the model to predict the methane production accurately with correlation coefficient of 0.87. The developed ANN model was used with genetic algorithm to optimize the methane size. The optimal amount of methane was converged to be 77%, which is greater than the maximum value obtained from the plant records of 70.1%. The operational conditions that resulted in the optimal methane production were determined as temperature at 36 °C, TS 6.6%, TVS 52.8% and pH 6.4.

Alarming visual display monitors affecting shower end use water and energy conservation in Australian residential households.

Abstract: Sustainable urban water consumption has become a critical issue in Australian built environments due to the country's dry climate and increasingly variable rainfall. Residential households have the potential to conserve water, especially across discretionary end uses such as showering. The advent of high resolution smart meters and data loggers allows for the disaggregation of water flow recordings into a registry of water end use events (e.g. showers, washing machine and taps). This study firstly reports on a water consumption end use study sample of 151 households conducted in the Gold Coast, Australia, with a focus on daily per capita shower end use distributions. A sub-sample of 44 households within the greater sample was recruited for the installation of an alarming visual display monitor locked at 40 L consumption for bathroom showers. All sub-sample shower end use event durations, volumes and flow rates were then analysed and compared utilising independent sample t-tests pre- and post-intervention. The installation of the shower monitor instigated a statistically significant mean reduction of 15.40 L (27%) in shower event volumes. Monetary savings resulting from modelled water and energy conservation resulted in a 1.65-year payback period for the device. Furthermore, conservative modelling indicated that the citywide implementation of the device could yield 3% and 2.4% savings in total water and energy consumption, respectively. Moreover, a range of non-monetary benefits were identified, including the deferment of water and energy supply infrastructure, reduced resource inflationary pressures, and climate change mitigation, to name a few. Resource consumption awareness devices like the one evaluated in this study assist resource consumers to take ownership of their usage and individually tackle individualistic and/or society driven conservation goals, ultimately helping to reduce the ecological footprint of built environments.

Sustainable solid waste management toward an inclusive society: Integration of the informal sector

Abstract: Waste is a subjective notion. Some see waste as a risk to public health and the environment, some see it as a mere aesthetic inconvenience, and others see it as a source of income. In the informal recycling sector, there is no question that waste is perceived as a resource. In Bandung, Indonesia, at least one in every 1000 people works in the informal sector, which includes recycling activities by scavengers or waste pickers in the street, in temporary storage sites, and at dump sites. Scavenging is always associated with risk, unhygienic environments, criminal activities, homelessness, unemployment, poverty, and backwardness. These associations tend to perpetuate discrimination against the informal recycling and, in turn, lead to exclusionary policies regarding the informal recycling in solid waste management (SWM). This paper discusses the role of informal recycling in SWM in Bandung, Indonesia, by using the material flow method. This study estimates at least 303 metric tons of refuse are collected by the informal recycling out of a total of 2295 metric tons of garbage generated each day in the city. This study also uses a questionnaire to investigate how local municipal officers and politicians perceive the role of the informal recycling. This paper further shows that despite the positive aspects that the informal recycling brings to SWM in Bandung, there are also negative consequences. It highlights the dilemma faced by decision makers while trying to include the informal recycling in the SWM toward inclusive society. Improved efficiency in waste collection may lead to unemployment of scavengers and waste pickers who belong to the poor strata of society, whereas issues on inclusive society force municipalities to fight against social exclusion. The normative theory of social exclusion and the concept of capital forms were used to address the dilemmas faced by decision makers in this sector.

A novel approach for the recycling of thin film photovoltaic modules

Abstract: A sustainable recycling of photovoltaic (PV) thin film modules gains in importance due to the considerable growing of the PV market and the increasing scarcity of the resources for semiconductor materials. The paper presents the development of two strategies for thin film PV recycling based on (wet) mechanical processing for broken modules, and combined thermal and mechanical methods for end-of-life modules. The feasibility of the processing steps was demonstrated in laboratory scale as well as in semi-technical scale using the example of CdTe and CIS modules. Pre-concentrated valuables In and Te from wet mechanical processing can be purified to the appropriate grade for the production of new modules. An advantage of the wet mechanical processing in comparison to the conventional procedure might be the usage of no or a small amount of chemicals during the several steps. Some measures are necessary in order to increase the efficiency of the wet mechanical processing regarding the improvement of the valuable yield and the related enrichment of the semiconductor material. The investigation of the environmental impacts of both recycling strategies indicates that the strategy, which includes wet mechanical separation, has clear advantages in comparison to the thermal treatment or disposal on landfills.

Copper content in animal manures and potential risk of soil copper pollution with animal manure use in agriculture

Abstract: With the rapid development of livestock and poultry production and the wide abuse of copper as an additive in most animal feeds in China, the risk of soil copper (Cu) pollution due to the use of animal manure in agriculture has become more and more focused. The objectives of this study were to investigate the concentrations of Cu in pig, cattle, chicken and sheep manure and in a variety of animal feeds in Beijing and Fuxin, and to assess the potential risk of soil Cu pollution due to the use of these manures in agriculture. We collected 215 samples of animal manures and 210 samples of animal feeds. The results showed that the mean Cu concentrations in pig, cattle, chicken and sheep feeds were 131.7, 22.4, 29.0, and 11.3 mg kg(-1), respectively. Copper concentrations. in the respective manures were 699.6, 31.8, 81.8, and 66.85 mg kg(-1). In addition, Cu concentrations in pig, cattle, and chicken manures were positively correlated to that in their feeds, respectively. The inventory of animal manures applied to land indicated that pig manure was the major source of Cu input both in Beijing and Fuxin. Calculation of the Cu loading rate showed that manure application might pose a potential risk to farmland according to the current standard issued by Chinese Ministry of Environmental Protection, especially in Beijing. This study may assist in understanding the risk of Cu from animal manure land application, aid in developing strategies to reduce the Cu input to agricultural lands and promote policies to protect soil quality. (C) 2010 Elsevier B.V. All rights reserved.

Iron ore and steel production trends and material flows in the world: Is this really sustainable?

Abstract: Material flow analysis is an analysis of the flow of a material into and out of a particular region. The flow analysis also includes estimation of energy expended and of environmental emissions at each stage of the material life cycle, i.e . from extraction, processing, consumption and recycling to disposal. This analysis informs resource policy, energy planning, environmental and waste management. This paper reports on a historical material flow analysis of the world iron ore and steel industry in which the material flow of iron ore and of crude steel products are quantified for the period from 1950 to 2005. On the basis of this analysis, the future production of iron and steel for the world is estimated. The historical analysis shows that the world iron ore production increased from 274 million tons (Mt) in 1950 to 1554 Mt in 2005, whereas the steel production increased from 207 to 1259 Mt. In addition, it is found that at the current level of production the world's identified iron ore reserves containing 230 billion tons of iron would last for nearly 50 years. Global CO 2 emissions from steel production from the different manufacturing routes are estimated to be 3169 Mt from approximately 1781 Mt of steel production by 2020, whereas the specific energy consumption is estimated to be 14.43 GJ/tcs. The analysis of historical production trends of iron ore and crude steel for the major iron ore and steel producing countries indicates that, incidentally, the major iron ore producing countries are not the major steel producing countries and vice-versa. For example, in 2005, Brazil's iron ore production was 322 Mt whereas its steel production was approximately 10% of its iron ore production. For the same period, Japan's steel production was 124 Mt though; it had no domestic iron ore production. The world flows of iron ore and steel clearly indicate that the weak end of the iron and steel industry is the time, cost and environmental emissions associated with the sea borne transport of materials. Further, a substance flow model for the year 2006 indicating the net flows of iron ore, crude and finished steel products across the continents demonstrates that these flows of materials is not environmentally sustainable, and the iron and steel sector could do a lot to contribute to sustainable development.

Survey of officials' awareness on circular economy development in China: Based on municipal and county level

Abstract: With rapid industrialization in China, both resource scarcity and resources efficiency have challenged the country's sustainable development. Under such circumstance, circular economy should be adopted as a national development strategy. However, due to a lack of understanding current barriers on implementing circular economy, it is necessary to conduct a questionnaire based survey. The data and information used in this paper were collected by distributing questionnaires in 6 cities and interviewing 252 respondents. Our research findings indicated that while most of officials working at municipal and county levels have higher awareness and understanding on circular economy concept and its significance, nearly 16.70% of the interviewed officials had just heard of circular economy indicating that there is still a need for government officials to further improve their circular economy awareness. Government officials can receive their circular economy knowledge through awareness raising activities thus obtaining higher circular economy awareness. The main barriers on circular economy development are weakness of public awareness and lack of financial support, the prior method on pushing circular economy development is to execute compulsory regulations, which is shared by about 61.11% of all respondents; the gap between policy-making and practical action is still a serious problem. Nearly half of the respondents are not willing to pay more money for green products.

Minimising carbon footprint of regional biomass supply chains

Abstract: A new method for regional energy targeting and supply chain synthesis is presented. A demand-driven approach is applied to assess the feasible ways for transferring energy from renewable sources to customers in a given region. The studied region is partitioned into a number of clusters by using the developed Regional Energy Clustering (REC) algorithm. The REC targets aim at minimising the system carbon footprint (CFP). The biomass energy supply and management are targeted using new graphical representations. Regional Energy Surplus–Deficit Curves (RESDC) visualises the formation and the sizes of introduced energy clusters. Regional Resource Management Composite Curve (RRMCC) an analogy of the Process Integration approach shows the energy imbalances helping in trading-off resources management. These graphical tools provide straightforward information of how to manage the surplus resources (biomass and land use) in a region.

Rainwater tanks in multi-unit buildings: A case study for three Australian cities

Abstract: Rainwater tanks have become popular in large Australian cities due to water shortage and greater public awareness towards sustainable urban development. Rainwater harvesting in multi-unit buildings in Australia is less common. This paper investigates the water savings potential of rainwater tanks fitted in multi-unit residential buildings in three cities of Australia: Sydney, Newcastle and Wollongong. It is found that for multi-unit buildings, a larger tank size is more appropriate to maximise water savings. It is also found that rainwater tank of appropriate size in a multi-unit building can provide significant mains water savings even in dry years. A prediction equation is developed which can be used to estimate average annual water savings from having a rainwater tank in a multi-unit building in these three Australian cities.

Assessment of Municipal Solid Waste management in Puducherry (Pondicherry), India

Abstract: Municipal Solid Waste (MSW) management is one of the most vital issues in the contemporary urban environments particularly in developing countries. Various aspects of MSW management in Puducherry, a small erstwhile French colony in Pondicherry Union Territory were assessed in order to improve the management practices. Its per capita generation rate and quantity in the city showed gradually increasing trend with passage of years. It was 265 tonnes/day (t/d) during 2003, which increased to 370 t/d in 2008, with a waste generation factor of 0.59 kg/capita/day. The sources of MSW classified into different categories and sub-categories showed domestic waste including kitchen waste, market waste, garden and agricultural waste, hospital waste, road and construction waste, sweeping and sanitary waste. Samples of MSW collected randomly from the main dumping yard at Karuvadikuppam in Puducherry, were categorized into biodegradable waste comprising 65% and non-biodegradable waste comprising 35%. MSW is dominated by yard waste (38.4%) followed by paper (30%) and plastics (10.4%) and the remaining 21.2% comprised of other waste. The municipalities in Puducherry adopted different methods such as door-to-door collection with segregation of garbage at source for effective MSW management. Composting of the organic waste included both aerobic composting and vermi-composting, and non-biodegradable waste was picked up and recycled for the final disposal of MSW. Awareness programs educating people regarding the problems as well as significance of MSW disposal were practiced through NGOs. However, it was found that there are some shortcomings in the existing MSW management practices, which need rectification.

Resources, properties and utilization of tar

Abstract: Demand for natural resources and energy, is increasing every day due to the rapid expansion of population and urbanization. Higher effective utilization such as reduction, reuse and recycle of the existing natural resources including waste becomes an important reason for the limited nature resource for change. Tar is an unavoidable waste or a by-product during biomass thermal conversion process (0.1-20% in biomass gasification, main product in biomass pyrolysis) or fossil thermal conversion (coal gasification, or liquefaction), whose utilization has an important influence on the efficiency of energy resource. Tar as resource and energy is reviewed in this study. The sources, properties and utilization styles of tar are summarized in detail, and some main companies related to tar production and handling are also introduced. (C) 2010 Elsevier B.V. All rights reserved.

Socio-technical transitions in water scarcity contexts: Public acceptance of greywater reuse technologies in the Metropolitan Area of Barcelona

Abstract: Greywater reuse systems are becoming more and more common in the new multi-storey buildings of the Metropolitan Area of Barcelona. A main driver of this trend has been the recent approval of ambitious local regulations aimed at saving water and using decentralised, alternative resources in a context of growing scarcity. Users must assume new responsibilities in water management and new capacities need to be developed at the very micro level to attain a successful implementation of these regulations. A survey of 120 greywater users and in-depth interviews with the main actors of the water sector was conducted in the town of Sant Cugat del Valles, in the Metropolitan Area of Barcelona. The municipality's six years experience on greywater use provided an exceptional opportunity to assess community perceptions during the socio-technical transition process. Sant Cugat was the first municipality in Spain that enforced the installation of such systems in new buildings. Results show that the perception of health risks, operation regimes, perceived costs and environmental awareness are, in different degrees, significant determinants of public acceptance. The main institutional, technical, and economic challenges that need to be addressed during the ongoing socio-technical transition process are also explored. Improving the level of knowledge of these systems among users would reduce the risk of social refusal of the new technology. Public authorities and implementers need to stimulate social learning processes with specific actions and build trust among residents in the new governance network if decentralised and alternative water supply systems are to find a place in the everyday life of urban populations.

The costs of municipal waste and recycling programs

Abstract: This paper estimates cost functions for both municipal solid waste collection and disposal services and curbside recycling programs. Cost data are obtained from a national survey of randomly selected municipalities. Results suggest, perhaps unsurprisingly, that both marginal and average costs of recycling systems exceed those of waste collection and disposal systems. Economies of scale are estimated for all observed quantities of waste collection and disposal. Economies of scale for recycling disappear at high levels of recycling—marginal and average cost curves for recycling take on the usual U-shape. Waste and recycling costs are also estimated as functions of factor costs and program attributes.

Realizing CO2 emission reduction through industrial symbiosis: A cement production case study for Kawasaki

Abstract: This article is one effort to examine the present and potential performances of CO2 emission reduction though industrial symbiosis by employing a case study approach and life cycle CO2 analysis for alternative industrial symbiosis scenarios. As one of the first and the best-known eco-town projects, Kawasaki Eco-town was chosen as a case study area. First, the current industrial symbiosis practices in this area are introduced. To evaluate the potential of reducing the total CO2 emission through industrial symbiosis, alternative industrial symbiosis scenarios are then designed based on a questionnaire survey of 57 major local industries, to which 35 companies appropriately responded. The main focus of this paper is to calculate the total CO2 emission for different scenarios by adopting a life cycle CO2 analysis method. We then present recommendations on further improvement with consideration of the local realities. Our findings are that industrial symbiosis practices in Kawasaki Eco-town still have room for improvement in that greenhouse gas emissions can be further reduced and natural resources conserved through effective material exchanges, not only between companies, but also with the surrounding area. To encourage material exchanges between the municipality and industry, the city government should introduce a detailed separation program for garbage collection so that wastes can be effectively reused. In addition, the Waste Disposal and Public Cleaning Law needs amending so that industries can effectively use municipal solid waste in their manufacturing.

Iron and steel in Chinese residential buildings: A dynamic analysis

Abstract: The rise of China to become world largest iron and steel producer and consumer since the late 1990s can be largely attributed to urbanization, with about 20% of China's steel output used by residential buildings, and about 50% for the construction sector as a whole. Previously, a dynamic material flow analysis (MFA) model was developed to analyze the dynamics of the rural and the urban housing systems in China. This model is expanded here to specifically analyze iron and steel demand and scrap availability from the housing sector. The evolution of China's housing stock and related steel is simulated from 1900 through 2100. For almost all scenarios, the simulation results indicate a strong drop in steel demand for new housing construction over the next decades, due to the expected lengthening of the – presently extremely short – life span of residential buildings. From an environmental as well as a resource conservation point of view, this is a reassuring conclusion. Calculations for the farther future indicate that the demand for steel will not just decrease but will rather oscillate: the longer the life spans of buildings, the stronger the oscillation. The downside of this development would be the overcapacities in steel production. A scenario with slightly lower life spans but a strong emphasis on secondary steel production might reduce the oscillation at moderate environmental costs.

Environmental assessment of home composting

Abstract: In this study the environmental burdens of home composting were determined using the life cycle assessment (LCA) tool. Data used for the LCA study such as gas emissions (CH4, N2O, NH3 and volatile organic compounds (VOCs)), tools and composter characteristics were obtained from an experimental home composting process of leftovers of raw fruits and vegetables (LRFV). Stable compost with a high content of nitrogen and organic matter was obtained. Neither pathogens nor phytotoxic compounds were found in the final compost. In relation to gaseous emissions, only volatile organic compounds (0.32 kg VOC/Mg LRFV) were detected, even though ammonia, methane and nitrous oxide emissions were also measured. Regarding environmental burdens, the composter was the major contributor to the total home composting process impact for the impact categories of abiotic depletion, ozone layer depletion, and cumulative energy demand. Gaseous emissions (based on our own measurements and literature data) caused the greatest contribution to the acidification, eutrophication, global warming and photochemical oxidation potentials.