Environmental and economic analysis of management systems for biodegradable waste

The management system for solid and liquid organic waste affects the environment and surrounding technical systems in several ways. In order to decrease the environmental impact and resource use, biological waste treatment and alternative solutions for sewage treatment are often advocated. These alternatives include increased agricultural use of waste residuals. To analyse whether such proposed systems indicate improvements for the environment and its sustainability, systems analysis is a useful method. The changes in environmental impact and resource use is not only a result of changes in waste treatment methods, but also largely a result of changes in surrounding systems (energy and agriculture) caused by changes in waste management practices. In order to perform a systems analysis, a substance-flow simulation model, the organic waste research model (ORWARE), has been used. The results are evaluated by using methodology from life cycle assessment (LCA). An economic analysis was also performed on three of the studied scenarios. The management system for solid organic waste and sewage in the municipality of Uppsala, Sweden, was studied. Three scenarios for different treatments of solid waste were analysed: incineration with heat recovery, composting, and anaerobic digestion. These three scenarios included conventional sewage treatment. A fourth scenario reviewed was anaerobic digestion of solid waste, using urine-separating toilets and separate handling of the urine fraction. The results are only valid for the case study and under the assumptions made. In this case study anaerobic digestion result in the lowest environmental impact of all the solid waste management systems, but is costly. Economically, incineration with heat recovery is the cheapest way to treat solid waste. Composting gives environmental advantages compared to incineration methods, without significantly increased costs. Urine separation, which may be implemented together with any solid waste treatment, has great advantages, particularly in its low impact on the environment. However, there is a large increase in acidification.     

A life cycle based multi-objective optimization model for the management of computer waste

The accelerating pace of waste generation from used electrical and electronic equipment is of growing global concern. Within this waste stream, computer hardware is quite significant in terms of both volume and risk to the environment because of the hazardous materials within it. The waste management hierarchy of prevention, reuse, recycle, treatment and disposal in landfill is accepted as a universal guideline for waste management. The contemporary concept of integrated solid waste management is very complex comprising of not only the environmental aspects or the technical aspects of the waste management hierarchy, but also incorporating economic, institutional, perceived risk and social issues in the context of complete life cycle of waste. Moreover, when to shift from one stage of hierarchy to another, is an involved decision warranting inclusion of several case specific issues. This paper presents a life cycle based multi-objective model that can help decision makers in integrated waste management. The proposed model has been applied to a case study of computer waste scenario in Delhi, India, which apart from having computer waste from its native population receives large quantities of imported second hand computers. The model has been used to evaluate management cost and reuse time span or life cycle of various streams of computer waste for different objectives of economy, perceived risk and environmental impact. The model results for different scenarios of waste generation have been analyzed to understand the tradeoffs between cost, perceived risk and environmental impact. The optimum life cycle of a computer desktop was observed to be shorter by 25% while optimizing cost than while optimizing impact to the environment or risk perceived by public. Proposed integrated approach can be useful for determining the optimum life cycle of computer waste, as well as optimum configuration of waste management facilities, for urban centers where computer waste related issues are of growing concern.     

A life cycle based multi-objective optimization model for the management of computer waste

The accelerating pace of waste generation from used electrical and electronic equipment is of growing global concern. Within this waste stream, computer hardware is quite significant in terms of both volume and risk to the environment because of the hazardous materials within it. The waste management hierarchy of prevention, reuse, recycle, treatment and disposal in landfill is accepted as a universal guideline for waste management. The contemporary concept of integrated solid waste management is very complex comprising of not only the environmental aspects or the technical aspects of the waste management hierarchy, but also incorporating economic, institutional, perceived risk and social issues in the context of complete life cycle of waste. Moreover, when to shift from one stage of hierarchy to another, is an involved decision warranting inclusion of several case specific issues. This paper presents a life cycle based multi-objective model that can help decision makers in integrated waste management. The proposed model has been applied to a case study of computer waste scenario in Delhi, India, which apart from having computer waste from its native population receives large quantities of imported second hand computers. The model has been used to evaluate management cost and reuse time span or life cycle of various streams of computer waste for different objectives of economy, perceived risk and environmental impact. The model results for different scenarios of waste generation have been analyzed to understand the tradeoffs between cost, perceived risk and environmental impact. The optimum life cycle of a computer desktop was observed to be shorter by 25% while optimizing cost than while optimizing impact to the environment or risk perceived by public. Proposed integrated approach can be useful for determining the optimum life cycle of computer waste, as well as optimum configuration of waste management facilities, for urban centers where computer waste related issues are of growing concern.     

Environmental impact and risk assessment of mineral wastes reuse strategies: Review and critical analysis of approaches and applications

In the industrial practice, the choice and evaluation of strategies of recycling and reuse of solid mineral wastes (thermal process residues, mining and quarrying wastes, construction and demolition wastes) could be based on ecological risk assessment (EcoRA) and life cycle assessment (LCA) studies also because of the substantial lack of regulations. Several methods and approaches of EcoRA and LCA have been developed so far and it is not always evident to consider a pertinent method for each application case. Furthermore, it is even less trivial to combine local and global scale results so to identify the best scenario from different alternatives.After a comprehensive review of recycling and reuse routes of mineral waste and relative legislation, this study addresses these issues by providing a detailed analysis and comparison of global and local scale impact assessment methods used in LCA and EcoRA, and finally an inventory of LCA and EcoRA studies already completed, to serve as a basis for further research.     

Transitions of municipal solid waste management. Part II: Hybrid life cycle assessment of Swiss glass-packaging disposal

In policy support of municipal solid waste (MSW) management, life cycle assessment (LCA) can serve to compare the environmental or economic impacts of two or more options for waste processing. The scope of waste management LCAs generally focuses less attention on future developments, e.g., where will recycling take place, and more on the environmental performance of prototypes, e.g., the incineration of all waste compared to recycling. To provide more robust support for Swiss waste glass-packaging disposal, scenarios of Swiss waste glass-packaging are assessed from a life cycle perspective. The scenarios consist in schemes for the disposal of the total amount of Swiss waste glass-packaging, i.e., different combinations of recycling and downcycling in Switzerland or abroad developed in Part I, Meylan et al. (2013). In this article (Part II), the disposal schemes are assessed with respect to eco-efficiency, an indicator that combines total environmental impacts and gross value added in Switzerland. Results show that no policy alternative guarantees environmental impact reductions and gross value added gains under all developments of exogenous constraints. Downcycling to foam glass in Switzerland is not only an environmentally sound disposal option, but it also buffers gross value added losses in case domestic recycling (and thus glass-packaging production in Switzerland) ceases in the future. The substitution of products based on raw materials other than Swiss cullet is the main responsible for change in environmental and economic impacts. Hence, an eco-efficiency maximizing policy should consider the products of disposal schemes. The combination of scenario analysis and eco-efficiency assessment as presented in this paper can be applied to other contexts (i.e., countries, waste fractions).     

Environmental sustainability assessment of food waste valorization options

Food waste can be valorized through different technologies, such as anaerobic digestion, incineration, and animal feed production. In this study we analyzed the environmental performance of two food waste valorization scenarios from a company of the retail sector in Belgium, through exergy analysis, exergetic life cycle assessment (ELCA), and a traditional life cycle assessment (LCA). In scenario 1 all food waste was considered to be valorized in an anaerobic digestion (producing electricity, heat, digestate and sorting the packaging material to be used as fuel for cement industry), while in scenario 2 a bread fraction was valorized to produce animal feed and a non-bread fraction was valorized in an anaerobic digestion (producing the same products on scenario 1, but in lower amounts). Scenario 2 was 10% more efficient than scenario 1 in the exergy analysis. For the ELCA and the single score LCA, scenario 2 presented lower environmental impacts than scenario 1 (32% and 26% lower, respectively). These results were mainly due to the avoided products from traditional supply chain (animal feed produced from agricultural products) and lower exergy loss at the feed production plant. Nevertheless, the high dry matter content of the bread waste played an important role on these results, therefore it should be pointed out that valorizing food waste to animal feed seems to be a better option only for the fractions of food waste with low water content (as bread waste).     

The evolution of municipal waste management in Europe: how different are national regimes?

The 1994 European Directive on Packaging and Packaging Waste allowed a diversity of conceptions of waste management to be developed and tested in various countries. Such a diversity may raise drawbacks related to the achievement of the single market and the European law of competition. The paper describes the main differences in waste management regimes in five countries: France, Germany, the Netherlands, Italy and Greece. This comparative approach allows us, first, to identify four main variables in order to characterize policy regimes, explaining the degree of orientation of waste regimes to cost-effectiveness. Second, we will show that implementation has resulted, in each country, in learning, correction and self-regulation, thus reducing the initial divergences between national regimes. Hence, efficient harmonization of waste management regimes may be achieved unexpectedly in a soft way without passing stringent European directives. Moreover, if policy-makers were to adopt explicitly the option of experimenting with competing organizational and policy concepts, as an approach to European harmonization, it would reveal, by 2004, the cost-effectiveness of alternative solutions at a time when European policy has to be reconsidered. Copyright © 2001 John Wiley & Sons, Ltd.     

An analysis of the use of life cycle assessment for waste co-incineration in cement kilns

Life cycle assessment, LCA, has become a key methodology to evaluate the environmental performance of products, services and processes and it is considered a powerful tool for decision makers. Waste treatment options are frequently evaluated using LCA methodologies in order to determine the option with the lowest environmental impact. Due to the approximate nature of LCA, where results are highly influenced by the assumptions made in the definition of the system, this methodology has certain non-negligible limitations. Because of that, the use of LCA to assess waste co-incineration in cement kilns is reviewed in this paper, with a special attention to those key inventory results highly dependent on the initial assumptions made. Therefore, the main focus of this paper is the life cycle inventory, LCI, of carbon emissions, primary energy and air emissions. When the focus is made on cement production, a tonne of cement is usually the functional unit. In this case, waste co-incineration has a non-significant role on CO₂ emissions from the cement kiln and an important energy efficiency loss can be deduced from the industry performance data, which is rarely taken into account by LCA practitioners. If cement kilns are considered as another waste treatment option, the functional unit is usually 1 t of waste to be treated. In this case, it has been observed that contradictory results may arise depending on the initial assumptions, generating high uncertainty in the results. Air emissions, as heavy metals, are quite relevant when assessing waste co-incineration, as the amount of pollutants in the input are increased. Constant transfer factors are mainly used for heavy metals, but it may not be the correct approach for mercury emissions.     

A mixed integer linear programming model for optimisation of organics management in an integrated solid waste system

In this paper, the authors propose a mixed integer linear programming model for designing an Integrated Solid Waste Management System (ISWMS) to meet specific economic goals. The model refers to a set of municipalities, known as ‘local basin’, which have to share a common waste management system. At the municipal level the model allows for an identification of the optimal collection service option; at the local basin level, the model provides the optimal waste flow appropriate to the collection service option of each municipality. The model has been applied to a full-scale case study of an area located in southeast Italy. A scenario analysis was carried out to investigate alternative municipal solid waste management options, which fundamentally differ in the organic flow mass rate to be either collected and composted or landfilled. Findings show that an increase in the cost of landfilling determines the optimal collection scenario and the configuration plants tend to recover higher rates of organics in separate collection and thus higher refuse derived fuel productions. The results obtained validate the application of the model in both the strategic planning and operational phases, by supporting public administrators at both municipality and local basin level in decision making and evaluation of technical and economic performances of ISWMSs.     

Product Stewardship,Waste Minimization and Economic Efficiency: Lessons from Germany

This paper introduces the concept of 'product stewardship' as a new policy approach towards solid waste management. The German Packaging Ordinance is analysed as a prototype of this new approach. Particular attention is paid to the economics of the Packaging Ordinance, to the practical implementation problems and to the likely impact of the planned EU Directive. Finally, what can be learned from the German experiences for the future design of waste management policies involving product stewardship is discussed.     

Assessing the “design paradox” with life cycle assessment: A case study of a municipal solid waste incineration plant

One of the most important processes in an integrated waste management system is incineration, which, among the different waste management disposal options still remains a critical waste treatment system. New dynamics and approaches have to be developed to embrace such a wide and complex topic, and better knowledge and assessment of incineration are strategically significant to define future environmental scenarios.Life cycle assessment (LCA), as a tool to optimise process-operating conditions and to support decision-making process, is often applied to investigate processes under design in various sectors, since choices made in the development phases can affect the future environmental profile. However, even if the greatest opportunity to improve a process from an environmental perspective is during the design phase, at the same time the knowledge is limited, in accordance with the so-called “design paradox”.Thus, in this context, this study used LCA methodology to quantitatively assess the extent to which the environmental impact of an incineration line reflects the environmental burdens perceived during the design phase. A comparative LCA was conducted at the design phase and under operating conditions at an Italian municipal solid waste incineration plant.The outcomes of the study indicated that for almost all of the categories analysed, the impacts associated with the process under design overestimated the impacts associated with the operating process, with the exception of climate change and water depletion. The results suggested that after the conduction of an LCA at the design phase of a process, an LCA of the operative conditions should be carried out to verify how much the over- or under-estimations affected the results.     

Using LCA to evaluate impacts and resources conservation potential of composting: A case study of the Asti District in Italy

Separate collection of municipal solid waste has overcome the 50% threshold in the Asti District in northern Italy, nearly one-third being composed of household and green organic waste. In order to address present and future solutions, it becomes therefore fundamental to assess the environmental performances of the current management of organic waste from separate collection. A from-gate-to-cradle life cycle assessment (LCA) model has been developed by expanding system boundaries, in order to carry out the assessment in the context of the whole waste management streamline. The environmental performances of an existing aerobic plant were made available, based on field measured data, by paying attention to the role and contribution of waste management subsystems. The need for actual and reliable data on materials and energy input, as well as gross and net gains from materials recovery, including benefits arising from use of compost in farming activities, was probably the major drawback that had to be faced. The study integrated the findings of different investigations from the literature with field measured data in order to obtain a more comprehensive framework representative of the area under study. The results may help public administrators to better understand the suitability of using LCA tools when dealing with solid waste management strategies.     

The Potential for Using Life Cycle Inventory Analysis in Local Authority Waste Management Decision Making

A life cycle inventory model was applied to a range of waste management scenarios in the waste collection authorities of Gloucestershire. The life cycle model and the results of modelling different waste management options are described. Model results were submitted to waste managers in the six authorities and utilization of the information was analysed. Analysis suggests that a range of factors arising from both model implementation and the local policy context affects the form and extent of utilization. Increased levels of environmental knowledge and understanding will be required to make effective use of life cycle analysis in local authority decision making.     

Using LCA to evaluate impacts and resources conservation potential of composting: A case study of the Asti District in Italy

Separate collection of municipal solid waste has overcome the 50% threshold in the Asti District in northern Italy, nearly one-third being composed of household and green organic waste. In order to address present and future solutions, it becomes therefore fundamental to assess the environmental performances of the current management of organic waste from separate collection. A from-gate-to-cradle life cycle assessment (LCA) model has been developed by expanding system boundaries, in order to carry out the assessment in the context of the whole waste management streamline. The environmental performances of an existing aerobic plant were made available, based on field measured data, by paying attention to the role and contribution of waste management subsystems. The need for actual and reliable data on materials and energy input, as well as gross and net gains from materials recovery, including benefits arising from use of compost in farming activities, was probably the major drawback that had to be faced. The study integrated the findings of different investigations from the literature with field measured data in order to obtain a more comprehensive framework representative of the area under study. The results may help public administrators to better understand the suitability of using LCA tools when dealing with solid waste management strategies.     

Economic viability of packaging waste recycling systems: A comparison between Belgium and Portugal

The Packaging and Packaging Waste Directive has had an undeniable impact on waste management throughout the European Union. Whereas recycling and recovery targets are the same, member states still enjoy a considerable degree of freedom with respect to the practical organization and management strategies adopted. Nevertheless, in all cases, the industry (which brings packaging material onto the market) should be responsible for the costs associated with packaging waste recycling/recovery (following the extended producer responsibility principle). The current paper compares and contrasts the institutional frameworks and financial costs and benefits of waste management operators for Belgium and Portugal. The unit costs of selective collection and sorting of packaging waste are provided for both countries. In Belgium, the costs of recycling seem to be fully supported by the industry (through Fost Plus, the national Green Dot agency). In Portugal the fairness of the recycling system depends on the perspective adopted (economic or strictly financial). Adopting a strictly financial perspective, it seems that Sociedade Ponto Verde (SPV, the Portuguese Green Dot agency) should increase the transfers to local authorities. However, the conclusions differ for this country if the avoided costs with refuse collection and other treatment are taken into account.     

Sound management of brominated flame retarded (BFR) plastics from electronic wastes: State of the art and options in Nigeria

Management of flame retarded plastics from waste electrical and electronic equipment (WEEE) has been posing a major challenge to waste management experts because of the potential environmental contamination issues especially the formation of polybrominated-dioxins and -furans (PBDD/F) during processing. In Nigeria, large quantities of electronic waste (e-waste) are currently being managed—a significant quantity of which is imported illegally as secondhand electronics. As much as 75% of these illegal imports are never reused but are rather discarded. These waste electronic devices are mostly older equipment that contains brominated flame retardants (BFRs) such as penta-brominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) which are presently banned in Europe under the EU WEEE and RoHS Directives. Risk assessment studies found both to be persistent, bio-accumulative and toxic. The present management practices for waste plastics from WEEE in Nigeria, such as open burning and disposal at open dumps, creates potential for serious environmental pollution. This paper reviews the options in the environmentally sound management of waste plastics from electronic wastes. Options available include mechanical recycling, reprocessing into chemicals (chemical feedstock recycling) and energy recovery. The Creasolv^® and Centrevap^® processes, which are the outcome of the extensive research at achieving sound management of waste plastics from WEEE in Europe, are also reviewed. These are solvent-based methods of removing BFRs and they presently offer the best commercial and environmental option in the sound management of waste BFR-containing plastics. Because these developments have not been commercialized, WEEE and WEEE plastics are still being exported to developing countries. The industrial application of these processes and the development of eco-friendlier alternative flame retardants will help assure sound management of WEEE plastics.     

LCA: A decision support tool for environmental assessment of MSW management systems

Life cycle assessment (LCA) can be successfully applied to municipal solid waste (MSW) management systems to identify the overall environmental burdens and to assess the potential environmental impacts. In this study, two methods used for current MSW management in Phuket, a province of Thailand, landfilling (without energy recovery) and incineration (with energy recovery), are compared from both energy consumption and greenhouse gas emission points of view. The comparisons are based on a direct activity consideration and also a life cycle perspective. In both cases as well as for both parameters considered, incineration was found to be superior to landfilling. However, the performance of incineration was much better when a life cycle perspective was used. Also, landfilling reversed to be superior to incineration when methane recovery and electricity production were introduced. This study reveals that a complete picture of the environmental performance of MSW management systems is provided by using a life cycle perspective.     

Implementing by-product management into the Life Cycle Assessment of the mussel sector

In Galicia (NW Spain), the mussel sector is an economic and social cornerstone, with great relevance at both regional and international scales. The environmental impact of this sector has been recently discussed from a Life Cycle Assessment (LCA) perspective. In previous studies, it was concluded that the management of mussel shells and mussel organic by-products needed to be implemented into future life cycle assessments. In this article, LCA methodology was used in order to assess the environmental performance of two valorization alternatives for mussel by-products: mussel shell valorization to produce calcium carbonate, and mussel organic remains valorization to produce pâté.From the environmental characterization for mussel shell valorization, propane and electricity production, sludge and ash management, haulage and atmospheric releases were identified as the hot-spots on which improvement potentials should be focused. Furthermore, the environmental profile for mussel shell valorization was compared to those for incineration and landfilling as alternative management options.The environmental characterization of pâté production from mussel organic by-product led to the recommendation of acting on the formulation of mussel pâté, the thermal energy demand and the product transport. Additionally, this valorization alternative was compared to another common scenario which considered the use of mussel organic by-product to manufacture fish meal.Finally, the valorization of mussel shells and organic by-products was implemented into the assessment of the Galician mussel sector. Thus, mussel by-product management was found to contribute to the potential environmental impacts to a lesser extent than mussel culture, purification and canning transformation.     

Environmental and economic aspects of production and utilization of RDF as alternative fuel in cement plants: A case study of Metro Vancouver Waste Management

Municipal solid waste (MSW) disposal and management is one of the most significant challenges faced by urban communities around the world. Municipal solid waste management (MSWM) over the years has utilized many sophisticated technologies and smart strategies. Municipalities worldwide have pursued numerous initiatives to reduce the environmental burden of the MSW treatment strategies. One of the most beneficial MSWM strategies is the thermal treatment or energy recovery to obtain cleaner renewable energy from waste. Among many waste-to-energy strategies, refuse-derived fuel (RDF) is a solid recovered fuel that can be used as a substitute for conventional fossil fuel. The scope of this study is to investigate the feasibility of RDF production with MSW generated in Metro Vancouver, for co-processing in two cement kilns in the region. This study investigates environmental impacts and benefits and economic costs and profits of RDF production. In addition, RDF utilization as an alternative fuel in cement kilns has been assessed. Cement manufacturing has been selected as one of the most environmentally challenged industries and as a potential destination for RDF to replace a portion of conventional fossil fuels with less energy-intensive fuel. A comprehensive environmental assessment is conducted using a life cycle assessment (LCA) approach. In addition, cost–benefit analysis (CBA) has been carried out to study the economic factors. This research confirmed that RDF production and use in cement kilns can be environmentally and economically viable solution for Metro Vancouver.     

Life-Cycle Impact Assessment of oil drilling mud system in Algerian arid area

The objective of this work is to assess the environmental impacts of the drilling mud system in Algeria's arid region. Water-based mud (WBM) and oil-based mud (OBM) are used during well drilling in Hassi Messaoud petroleum field, and have a considerable pollution potential particularly on the aquifer system which constitutes the single resource of drinking water in the Sahara. The Life-Cycle Assessment (LCA) approach is applied to evaluate the impacts of several drilling mud systems across all stages of their life cycle, e.g. use, treatment and disposal. Environmental impacts of five treatments scenarios corresponding to the drilling waste management applied in Hassi Messaoud are compared: reserve pit without treatment (burial option), secondary high centrifugation (vertical cuttings dryer), stabilisation/solidification online, stabilisation/solidification off line and thermal desorption. The impact assessment is carried on using the LCIA models of Impact 2002+ method in SIMAPRO7 software. This assessment identifies human toxicity and terrestrial eco-toxicity as the major impact categories in this specific arid context and quantifies the emissions contributions. The local environmental impact is the most important of the drilling mud life cycle and is mainly linked to emissions from reserve pits, treated cuttings, and drilling phase 16″ through the Turonian and Albian aquifer. The main contributing substances are aromatic hydrocarbons fraction and metals in particular barium, zinc, antimony, arsenic, and aluminium. Concerning the comparison of the treatment scenarios, it appears that stabilisation/solidification online is the best one; it has the lowest impact score in the two dominating categories because of the waste minimisation: mud storage avoided in the reserve pit. The second best scenario is the thermal desorption which obtains the lowest impact score in carcinogen effects due to hydrocarbons reduction (<1%) and avoided impacts of recovered oil. The toxic substances fate modeling will be improved by taking into account their site-specific impact.