Material Recovery Facility Research Articles

Recycling of glass: accounting of greenhouse gases and global warming contributions

Greenhouse gas (GHG) emissions related to recycling of glass waste were assessed from a waste management perspective. Focus was on the material recovery facility (MRF) where the initial sorting of glass waste takes place. The MRF delivers products like cullet and whole bottles to other industries. Two possible uses of reprocessed glass waste were considered: (i) remelting of cullet added to glass production; and (ii) re-use of whole bottles. The GHG emission accounting included indirect upstream emissions (provision of energy, fuels and auxiliaries), direct activities at the MRF and bottle-wash facility (combustion of fuels) as well as indirect downstream activities in terms of using the recovered glass waste in other industries and, thereby, avoiding emissions from conventional production. The GHG accounting was presented as aggregated global warming factors (GWFs) for the direct and indirect upstream and downstream processes, respectively. The range of GWFs was estimated to 0-70 kg CO(2)eq. tonne( -1) of glass waste for the upstream activities and the direct emissions from the waste management system. The GWF for the downstream effect showed some significant variation between the two cases. It was estimated to approximately -500 kg CO(2)-eq. tonne(- 1) of glass waste for the remelting technology and -1500 to -600 kg CO(2)-eq. tonne(-1) of glass waste for bottle re-use. Including the downstream process, large savings of GHG emissions can be attributed to the waste management system. The results showed that, in GHG emission accounting, attention should be drawn to thorough analysis of energy sources, especially electricity, and the downstream savings caused by material substitution.

Case study: Determination of the economic and operational feasibility of a material recovery facility for municipal recycling in Lucas County, Ohio, USA

Solid waste minimization and recycling goals for municipalities are achievable through the installation of material recovery facilities (MRFs) and in certain solid waste management systems, government owned and operated MRFs are feasible and cost justified. The aim of this paper is to demonstrate a structured process to evaluate and determine the operational and economic feasibly of a government owned MRF that is based on financial engineering. As a companion, a case study from Lucas County, Ohio (USA) is provided that demonstrated this analysis process. In addition, the paper explores the impact of uncertainty in decision alternatives by placing a strong emphasis on economic efficiencies and a sensitivity analysis of the results to changes in the data inputs, specifically inflation, recycling levels, and recycling commodity market shifts. The key findings from the research indicate that the municipality will achieve a payback period of approximately 4 years, and a 10 years internal rate of return of 20.5%, versus the current system of out souring. The consequences of these findings, stemming from the economic and operational justification, led to the actual purchase of a MRF site for Lucas County, Ohio (USA). This research may serve as an example or model for other local governments considering the implementation of such a system.

Use of stratified cluster sampling for efficient estimation of solid waste generation at household level

Relatively few studies have been performed to characterize municipal solid waste (MSW) at household level. This is due in part to the difficulties involved with collecting the data and selecting an appropriate statistical sample size. The previous studies identified in this paper have used statistical tools appropriate for analysing data collected at a material recovery facility or landfill site. This study demonstrates a statistically sound and efficient approach for characterizing MSW at the household level. Moreover, a household approach also allowed for consideration of the socio-economic conditions, level of waste generation, geography, and demography. The study utilized two-stage cluster sampling within strata in Kathmandu Metropolitan City (KMC) to measure MSW for 2 weeks. In KMC, the average household solid waste generation was 161.2 g capita( -1) day(- 1)with an average generation rate between 137.7 and 184.6 g capita(-1) day(-1) for a 95% confidence interval and 14.5% relative margin of error. The results show a positive relation between income and waste production rate. Organic waste was the biggest portion of MSW, and hazardous waste was the smallest of the total. Sample size considerations suggest that 273 households are required in KMC to attain a 10% relative margin of error with a 95% confidence interval.

A multicriteria facility location model for municipal solid waste management in North Greece

Up to 2002, Hellenic Solid Waste Management (SWM) policy specified that each of the country’s 54 prefectural governments plan its own SWM system. After 2002, this authority was shifted to the country’s 13 regions entirely. In this paper, we compare and contrast regional and prefectural SWM planning in Central Macedonia. To design the prefectural plan, we assume that each prefecture must be self-sufficient, and we locate waste facilities in each prefecture. In contrast, in the regional plan, we assume cooperation between prefectures and locate waste facilities to serve the entire region. We present a new multicriteria mixed-integer linear programming model to solve the location–allocation problem for municipal SWM at the regional level. We apply the lexicographic minimax approach to obtain a “fair” nondominated solution, a solution with all normalized objectives as equal to one another as possible. A solution to the model consists of locations and technologies for transfer stations, material recovery facilities, incinerators and sanitary landfills, as well as the waste flow between these locations.

The impact of municipal solid waste treatment methods on greenhouse gas emissions in Lahore, Pakistan

The contribution of existing municipal solid waste management to emission of greenhouse gases and the alternative scenarios to reduce emissions were analyzed for Data Ganj Bukhsh Town (DGBT) in Lahore, Pakistan using the life cycle assessment methodology. DGBT has a population of 1,624,169 people living in 232,024 dwellings. Total waste generated is 500,000 tons per year with an average per capita rate of 0.84kg per day. Alternative scenarios were developed and evaluated according to the environmental, economic, and social atmosphere of the study area. Solid waste management options considered include the collection and transportation of waste, collection of recyclables with single and mixed material bank container systems (SMBCS, MMBCS), material recovery facilities (MRF), composting, biogasification and landfilling. A life cycle inventory (LCI) of the six scenarios along with the baseline scenario was completed; this helped to quantify the CO2 equivalents, emitted and avoided, for energy consumption, production, fuel consumption, and methane (CH4) emissions. LCI results showed that the contribution of the baseline scenario to the global warming potential as CO2 equivalents was a maximum of 838,116 tons. The sixth scenario had a maximum reduction of GHG emissions in terms of CO2 equivalents of -33,773 tons, but the most workable scenario for the current situation in the study area is scenario 5. It saves 25% in CO2 equivalents compared to the baseline scenario.

Life cycle assessment of solid waste management options for Eskisehir, Turkey

Life cycle assessment (LCA) methodology was used to determine the optimum municipal solid waste (MSW) management strategy for Eskisehir city. Eskisehir is one of the developing cities of Turkey where a total of approximately 750tons/day of waste is generated. An effective MSW management system is needed in this city since the generated MSW is dumped in an unregulated dumping site that has no liner, no biogas capture, etc. Therefore, five different scenarios were developed as alternatives to the current waste management system. Collection and transportation of waste, a material recovery facility (MRF), recycling, composting, incineration and landfilling processes were considered in these scenarios. SimaPro7 libraries were used to obtain background data for the life cycle inventory. One ton of municipal solid waste of Eskisehir was selected as the functional unit. The alternative scenarios were compared through the CML 2000 method and these comparisons were carried out from the abiotic depletion, global warming, human toxicity, acidification, eutrophication and photochemical ozone depletion points of view. According to the comparisons and sensitivity analysis, composting scenario, S3, is the more environmentally preferable alternative. In this study waste management alternatives were investigated only on an environmental point of view. For that reason, it might be supported with other decision-making tools that consider the economic and social effects of solid waste management.

A Sustainable Approach to the Remediation of the Payatas Disposal Facility in Metro Manila, Philippines

AbstractThe municipal solid waste management crisis facing the Payatas disposal facility in Metro Manila, Philippines underscores the urgent need for sustainable solutions to address leachate contamination, the geotechnical instability of the dumpsite, landfill gas generation and the safety and health of facility workers and residents. A team of environmental engineers selected the site as a design project for the Mondialogo Worldwide Engineering Award and identified the following engineering solutions suitable for the remediation of the dumpsite: slope reinforcement anchors, soil-bentonite vertical impermeable barriers, an impermeable dumpsite cap, a perimeter drainage system, a leachate recirculation system, a facultative lagoon and constructed wetland system, a methane gas collection and power generation system, and a materials recovery facility. The proposed management system and financial remediation strategy requires the local government to spearhead the programme with funding to be derived from international loans and grants. It is recommended that the energy recovery component of the project be funded under the clean development mechanism, in which the certified emissions reductions (CERs) generated may be used to offset the capital outlay for the retrofitting of the engineering solutions and continuance of the remediation programme. The proposed remediation programme addresses the Millennium Development Goals set by the Philippine government relating to protection of the environment, improvement of health and sanitation, and the enhancement of energy services and community income sharing gained from surplus CERs.

Truck sizing models for recyclables pick-up

Growing public concerns about the environmental consequences of waste disposal have led to an increase in recycling efforts. In many communities, curbside collection programs have been instituted for collecting recyclables from households for transfer to material recovery facilities. In most programs the cost of collection is the dominant cost. Despite the high cost and environmental importance of collecting recyclables from households, most municipal collection systems are designed and operated without a clear understanding of what factors drive those costs and how they might be reduced. In this paper, models for determining truck configurations, as well as optimal compartment sizes for recyclables collection are developed. Constraints arising from the operation of the trucks are formulated, and solution schemes are presented. In addition, a procedure for optimally partitioning a vehicle used to collect source-separated material is discussed. Several scenario based planning approaches are developed. Use of the truck sizing models as an industry decision tool and the associated benefits of applying the truck sizing models and the solution methodology to a contract based collection program are also discussed.

Estimation of future outflows and infrastructure needed to recycle personal computer systems in California

The objectives of the present study are to estimate future quantities of electronic waste (e-waste) for which appropriate infrastructure needs to be established, and to the estimate the total cost for e-waste recycling in California. Estimation of the future amounts of e-waste as a function of time is critical to effective e-waste management. To generate estimates, we use a time-series materials flow analysis model (MFAM). The model estimates future e-waste quantities by modeling the stages of production, usage, and disposal. We consider four scenarios for the estimation of future e-waste generation in order to consider the effects of exportation outside the State of California and of user preferences to store or to recycle the e-waste. These efforts were further investigated through the use of sensitivity analysis. The results of the present research indicate that the outflow (recycling) amount of central processing units (CPUs) will increase and will reach approximately 8.5 million units per year in 2013, but the outflow (recycling) of cathode ray tube (CRT) monitors will decrease from 2004 in California because of the replacement of CRT monitors by liquid crystal display (LCD) monitors. In 2013, the cost for CPU recycling will be 1.7 times higher than that in 2005. But for CRT monitors, the cost for recycling in 2013 will be negligible. After the State of California enacted the ban on landfill disposal of e-waste, recycling became the most common end-of-life (EOL) option in California. Also, after 2005, the State of California will need more than 60 average-capacity materials recovery facilities (MRFs), to recycle the number of personal computer systems generated, which represents an investment in capital of over $16 million.

Economic Analysis of Electronic Waste Recycling: Modeling the Cost and Revenue of a Materials Recovery Facility in California

The objectives of this study are to identify the various techniques used for treating electronic waste (e-waste) at material recovery facilities (MRFs) in the state of California and to investigate the costs and revenue drivers for these techniques. The economics of a representative e-waste MRF are evaluated by using technical cost modeling (TCM). MRFs are a critical element in the infrastructure being developed within the e-waste recycling industry. At an MRF, collected e-waste can become marketable output products including resalable systems/components and recyclable materials such as plastics, metals, and glass. TCM has two main constituents, inputs and outputs. Inputs are process-related and economic variables, which are directly specified in each model. Inputs can be divided into two parts: inputs for cost estimation and for revenue estimation. Outputs are the results of modeling and consist of costs and revenues, distributed by unit operation, cost element, and revenue source. The results of the present analysis indicate that the largest cost driver for the operation of the defined California e-waste MRF is the materials cost (37% of total cost), which includes the cost to outsource the recycling of the cathode ray tubes (CRTs) (dollar 0.33/kg); the second largest cost driver is labor cost (28% of total cost without accounting for overhead). The other cost drivers are transportation, building, and equipment costs. The most costly unit operation is cathode ray tube glass recycling, and the next are sorting, collecting, and dismantling. The largest revenue source is the fee charged to the customer; metal recovery is the second largest revenue source.

Life cycle assesment of municipal solid waste management methods: Ankara case study

Different solid waste management system scenarios were developed and compared for the Municipal Solid Waste Management System of Ankara by using the life cycle assessment (LCA) methodology. The solid waste management methods considered in the scenarios were collection and transportation of wastes, source reduction, Material Recovery Facility (MRF)/Transfer Stations (TS), incineration, anaerobic digestion and landfilling. The goal of the study was to determine the most environmentally friendly option of MSWM system for Ankara. The functional unit of the study was the amount of solid waste generated in the system area of concern, which are the districts of Ankara. The life cycle inventory analysis was carried out by IWM Model-1. The inputs and outputs of each management stage were defined and the inventory emissions calculated by the model were classified in to impact categories; non-renewable energy sources exhausting potential, final solid waste as hazardous and non-hazardous, global warming, acidification, eutrophication and human toxicity. The impacts were quantified with the weighing factors of each category to develop the environmental profiles of each scenario. In most of the categories, Source Reduction Scenario was found to be the most feasible management method, except the global warming category. The lowest contribution to GWP was calculated for the anaerobic digestion process. In the interpretation and improvement assessment stage, the results were further evaluated and recommendations were made to improve the current solid waste management system of Ankara.

Internet-based Fuzzy Multicriteria Decision Support System for Planning Integrated Solid Waste Management

Solid waste management planning involves selecting a best combination of solid waste management options. The decision involves the perceptions and preferences of different groups of people and multiple, sometimes conflicting, project objectives that are expressed in subjective terms. As reported in this paper, these issues were addressed by developing a fuzzy multicriteria decision support system. An internet-based user-interactive decision-support application was developed based on fuzzy logic. Community specific data are stored in a centralized database and are accessible to others through a web browser. The decision support system is a tool for decision makers and environmental professionals to use in conducting local and regional integrated solid waste management planning. A case study was conducted to illustrate the application of the models. The case study evaluated eight alternatives for managing the waste stream entering the City of Columbia Sanitary Landfill and utilized waste characterization data, other solid waste related data from the City of Columbia and the open literature, as well as preferences assigned by the researchers. The results showed that an assigned Alternative 4, which is a combination of Material Recovery Facility (MRF) and Refuse-Derived Fuel Facility (RDF) could be distinguished as the alternative that best met the established criteria. The sensitivity analysis showed that the fuzzy ranking results were not sufficiently sensitive to the different aggregation operators for combining the fuzzy importance factors. The comparison of different composition operators showed that the sum-product composition operator allows greater differentiation in the solid waste management context.

Optimal design for sustainable development of a material recovery facility in a fast-growing urban setting

Installing material recovery facilities (MRFs) in a solid waste management system could be a feasible alternative to achieve sustainable development goals in urban areas if current household and curbside recycling cannot prove successful in the long run. This paper addresses the optimal site selection and capacity planning for a MRF in conjunction with an optimal shipping strategy of solid waste streams in a multi-district urban region. Screening of material recovery and disposal capacity alternatives can be achieved in terms of economic feasibility, technology limitation, recycling potential, and site availability. The optimization objectives include economic impacts characterized by recycling income and cost components for waste management, while the constraint set consists of mass balance, capacity limitation, recycling limitation, scale economy, conditionality, and relevant screening constraints. A case study for the City of San Antonio, Texas (USA) presents a vivid example where scenario planning demonstrates the robustness and flexibility of this modeling analysis. It proves especially useful when determining MRF ownership structure. Each scenario experiences two case settings: (1) two MRF sites are proposed for selection and (2) a single MRF site is sought. Cost analysis confirms processing fees are not the driving force in the City’s operation, but rather shipping cost. Sensitivity analysis solidifies the notion that significant public participation plays the most important role in minimizing solid waste management expenses.

Sustainable pattern analysis of a publicly owned material recovery facility in a fast-growing urban setting under uncertainty

Sustainable development goals are achievable through the installation of Material Recovery Facilities (MRFs) in certain solid waste management systems, especially those in rapidly expanding multi-district urban areas. MRFs are a cost-effective alternative when curbside recycling does not demonstrate long-term success. Previous capacity planning uses mixed integer programming optimization for the urban center of the city of San Antonio, Texas to establish that a publicly owned material recovery facility is preferable to a privatized facility. As a companion study, this analysis demonstrates that a MRF alleviates economic, political, and social pressures facing solid waste management under uncertainty. It explores the impact of uncertainty in decision alternatives in an urban environmental system. From this unique angle, waste generation, incidence of recyclables in the waste stream, routing distances, recycling participation, and other planning components are taken as intervals to expand upon previous deterministic integer-programming models. The information incorporated into the optimization objectives includes economic impacts for recycling income and cost components in waste management. The constraint set consists of mass balance, capacity limitation, recycling limitation, scale economy, conditionality, and relevant screening restrictions. Due to the fragmented data set, a grey integer programming modeling approach quantifies the consequences of inexact information as it propagates through the final solutions in the optimization process. The grey algorithm screens optimal shipping patterns and an ideal MRF location and capacity. Two case settings compare MRF selection policies where optimal solutions exemplify the value of grey programming in the context of integrated solid waste management.

Recycling in a Megacity

In the aftermath of the 9/11 disaster, Mayor Bloomberg of New York City unveiled an aggressive budget plan that included the temporary suspension of glass and plastics recycling. This was considered by many to be anti-environmental, but the results of this study show that for lack of markets, even at zero or negative prices, nearly 90% of the plastic and glass set aside by thoughtful New Yorkers was transported to materials recovery facilities (MRFs) and from there to landfills. Sending bales of plastics to landfills is not limited to New York City. It is an environmental paradox that the United States is digging up new oil fields in pristine areas and, at the same time, continues to convert greenfields to brownfields by burying nearly 20 million tons of plastic fuel annually. The study also determined that at the present rate of source separation, estimated to be less than 30% of the available recyclables in 1999, building large, modern MRFs may increase substantially the rate of New York City recycling and also allow single-stream collection of commingled recyclables, as is done in Phoenix, AZ. Single-stream collection simplifies separation at the source by citizens and increases the amount of collected recyclables. Also, because collection represents a large fraction of the costs of waste management, it may have a significant economic advantage.

Solid waste management practices and review of recovery and recycling operations in Turkey

This paper provides a general overview of solid waste data and management practices employed in Turkey during the last decade. Municipal solid waste statistics and management practices including waste recovery and recycling initiatives have been evaluated. Detailed data on solid waste management practices including collection, recovery and disposal, together with the results of cost analyses, have been presented. Based on these evaluations basic cost estimations on collection and sorting of recyclable solid waste in Turkey have been provided. The results indicate that the household solid waste generation in Turkey, per capita, is around 0.6 kg/year, whereas municipal solid waste generation is close to 1 kg/year. The major constituents of municipal solid waste are organic in nature and approximately 1/4 of municipal solid waste is recyclable. Separate collection programmes for recyclable household waste by more than 60 municipalities, continuing in excess of 3 years, demonstrate solid evidence for public acceptance and continuing support from the citizens. Opinion polls indicate that more than 80% of the population in the project regions is ready and willing to participate in separate collection programmes. The analysis of output data of the Material Recovery Facilities shows that, although paper, including cardboard, is the main constituent, the composition of recyclable waste varies strongly by the source or the type of collection point.

Garbage wars: the struggle for environmental justice in Chicago

Review: Garbage Wars: The Struggle for Environmental Justice in Chicago By David Naguib Pellow Reviewed by Alan L. Chan Chinese Lutheran Church, San Francisco, USA David Naguib Pellow. Garbage Wars: The Struggle for Environmental Justice in Chicago. Cambridge, MA: MIT Press, 2002. 234 pp. ISBN 0-262-16212- 1 (cloth). US$24.95 The question that motivated Pellow to write this book was: what are the origins of environmental inequality and environmental racism with regard to policies on the management of solid waste in urban areas? (p. 5) The author is an Associate Professor in the Department of Ethnic Studies at the University of California, San Diego. As the title suggests, Garbage Wars: The Struggle for Environmental Justice in Chicago is an analysis of the politics of garbage in Chicago, in particular, and the United States, in general. There are altogether seven chapters plus an extensive 21-page reference section in this book. The topics of the seven chapters are: 1. Waste, Politics, and Environmental Injustice; 2. A Social History of Waste, Race, and Labor, Part I: Movements, Technology, and Politics, 1880s-1930s; 3. A Social History of Waste, Race, and Labor, Part II: Waste Management and Waste Conflicts, 1940s-2000; 4. The Movement for Environmental Justice in Chicago and the United States; 5. Working for the Movement: Recycling Labor at the Resource Center; 6. The Next Evolutionary Stage: Recycling Waste or Recycling History?; and 7. Toward Environmental Justice. As an activist-scholar, Pellow frames the garbage wars as a struggle against environmental racism, rather than simply battles over natural resource management and community resources (p. vii). Realizing the complexity and disturbing reality of environmental racism, he agues that not only are local and/or state governments and industry often guilty of perpetrating acts of injustice, but often environmentalists and certain people of color are also implicated in creating these problems. Pellow did historical studies of waste management, from horse and cart to compactor trucks and dumpsters; and from city dumps, incinerators, reduction plants, and sanitary landfills to materials recovery facilities and the recycling industry. Using case studies and the anthropological method of participant-observation, he supports his findings with facts as well as firsthand experience. Pellow investigates the most vilified waste hauler in

Reduction of queuing delays at waste management facilities

ile waiting to unload materials at waste management facilities such as landfill sites, transfer stations, and material recovery facilities. These delays can be costly since the program operator must pay for these trucks and their crews to sit idly. Previous studies of delays at unloading facilities have often focussed on reducing unloading times, primarily through capital improvements such as providing twin scale houses and additional unloading bays. Most of these studies assume that the "arrival pattern of the collection vehicles is beyond the control of the analyst. This work assumes that the physical layout of the unloading facility is fixed and examines the effect that changes in the arrival times of collection vehicles will have on queuing delays at the facility. Both deterministic and fluid flow approaches to the analysis of queuing delays at unloading facilities are presented. The results show that congestion at unloading facilities is often caused by the assignment of approximately equal workloads to each collection crew and that relatively minor differences in workload assignments can substantially reduce queuing delays. The results of the analysis are confirmed through Monte Carlo simulation modelling.

Diversion from landfill: mechanical recycling of plastics from materials recovery facilities and from shredder residue

Diversion from landfill of post-consumer and shredder residue plastics can occur through some simple mechanical recycling techniques. Mechanically recycled post-consumer high-density polyethylene (HDPE) has been remoulded into bottle shapes. Both the chemical and mechanical properties of this polymer have been analysed and found to behave as well as the virgin material. Polyolefin plastic, separated from a complex mixture of shredder residue, has been remoulded into test samples and also compares favourably to a sample of the virgin polymer.

Pilot-scale gasification of municipal solid wastes by high-rate and two-phase anaerobic digestion (TPAD)

Bioconversion of municipal solid waste-sludge blend by conventional high-rate and two-phase anaerobic digestion was studied. RDF (refused-derived fuel)-quality feed produced in a Madison, Wisconsin, USA, MRF (materials-recovery facility) was used. High-rate digestion experiments were conducted with bench-scale digesters under target operating conditions developed from an economic feasibility study. The effects of digestion temperature, RDF content of digester feed, HRT, loading rate, RDF particle size, and RDF pretreatment with cellulase or dilute solutions of NaOH or lime on digester performance were studied. A pilot-scale two-phase digestion plant was operated with 80:20 (weight ratio) RDF-sludge blends to show that this process exhibited a higher methane yield, and produced a higher methane-content digester gas than those obtained by single-stage, high-rate anaerobic digestion.