Post-consumer Products Research Articles

A decision tool for disassembly process planning under end-of-life product quality

One of the major sources of uncertainty in disassembly systems is the quality or states of post-consumer products. This paper develops a decision tool for disassembly process planning under variability of the End-of-Life product quality. The objective is to maximize the profit of the disassembly process. This latter is calculated as the difference between the revenue generated by recovered parts and the cost of the disassembly tasks. The revenue of a product (or a subassembly, or a component) depends on its quality. The proposed methodology helps to take decisions about the best disassembly process and the depth of disassembly, depending on the quality of the products to be disassembled. Industrial applicability and interest are shown using an industrial case focused on the remanufacturing of mechatronic parts in the automotive industry.

Looking Down Under for a Circular Economy of Indium.

Indium is a specialty metal crucial for modern technology, yet it is potentially critical due to its byproduct status in mining. Measures to reduce its criticality typically focus on improving its recycling efficiency at end-of-life. This study quantifies primary and secondary indium resources ("stocks") for Australia through a dynamic material-flow analysis. It is based on detailed assessments of indium mineral resources hosted in lead-zinc and copper deposits, respective mining activities from 1844 to 2013, and the trade of indium-containing products from 1988 to 2015. The results show that Australia's indium stocks are substantial, estimated at 46.2 kt in mineral resources and an additional 14.7 kt in mine wastes. Australian mineral resources alone could meet global demand (∼0.8 kt/year) for more than five decades. Discarded material from post-consumer products, instead, is negligible (43 t). This suggests that the resilience of Australia's indium supply can best be increased through efficiency gains in mining (such as introducing domestic indium refining capacity) rather than at the end of the product life. These findings likely also apply to other specialty metals, such as gallium or germanium, and other resource-dominated countries. Finally, the results illustrate that national circular economy strategies can differ substantially.

Planning the location of facilities to implement a reverse logistic system of post-consumer packaging using a location mathematical model.

The implementation of reverse logistics systems (RLS) for post-consumer products provides environmental and economic benefits, since it increases recycling potential. However, RLS implantation and consolidation still face problems. The main shortcomings are the high costs and the low expectation of broad implementation worldwide. This paper presents two mathematical models to decide the number and the location of screening centers (SCs) and valorization centers (VCs) to implement reverse logistics of post-consumer packages, defining the optimum territorial arrangements (OTAs), allowing the inclusion of small and medium size municipalities. The paper aims to fill a gap in the literature on RLS location facilities that not only aim at revenue optimization, but also the participation of the population, the involvement of pickers and the service universalization. The results showed that implementation of VCs can lead to revenue/cost ratio higher than 100%. The results of this study can supply companies and government agencies with a global view on the parameters that influence RLS sustainability and help them make decisions about the location of these facilities and the best reverse flows with the social inclusion of pickers and serving the population of small and medium-sized municipalities.

Microbial Recycling of Precious and Rare Metals Sourced from Post-Consumer Products

We have focused on the metal-reducing bacterium, Shewanella algae that are able to reduce and deposit platinum group metals (Pt (IV), Pd (II) and Rh (III)) and gold (Au (III)) in neutral solutions at room temperature under anaerobic conditions. When processing the aqua regia solution of spent automotive catalysts, the solution pH was adjusted to the optimal range for S. algae activity between pH 4 and 7. After this pH adjustment, the S. algae cells were able to rapidly and selectively reduce and accumulate the platinum group metal ions from the leaching solution into the bacterial cells as metallic nanoparticles. The biotechnological procedure also has the potential to allow the recovery of Au (III) ions from the leaching solution of electronic waste. We also found that the S. algae cells were also applicable to the adsorption of rare metal ions from acidic solutions. We achieved selective adsorption of indium (In (III)) ions on the bacterial cells from the leaching solution of waste liquid crystal displays by adjusting its pH, because the pH range necessary for S. algae to act as an effective adsorbent differs for different metal ions. Our proposed microbial methods enable the rapid and highly efficient recovery of precious and rare metals sourced from post-consumer products.

Curable precursors derived from chemical recycling of poly(ethylene terephthalate) and polylactic acid and physical properties of their thermosetting (co)polyesters

Curable precursors for production of thermosetting (co)polyesters are developed based on poly(butylene adipate) (PBA), poly(ethylene terephthalate), and poly(lactic acid) (PLA). The precursors are prepared from methacrylation of their hydroxyl-terminated oligomers. These include commercial HO-capped PBA prepolymer (HO-PBA), and bis-2-hydroxyethyl terephthalate (BHET) and glycolized PLA (GPLA), which are obtained from glycolysis reactions of their post-consumer products and original resin. The optimal conditions for methacrylation of each prepolymer, i.e., molar ratios of prepolymer to methacrylic anhydride (MAAH), temperature and time, are examined. The most efficient conditions are 1:4/120 °C/3 h (HO-PBA), 1:2.5/120 °C/2 h (BHET), and 1:4/140 °C/3 h (GPLA), respectively. These conditions are justified, where the highest degree of substitution and double bond content are obtained without self-curing side reaction. The resulting methacrylated precursors from HO-PBA and BHET are isothermally cured faster than those of GPLA. Thermosetting copolyesters developed from binary mixtures of the precursors possess tunable thermal stability, and physical and mechanical properties. The degradable copolyesters can be applied in various applications, especially in packaging and agricultural fields.

Design, management and control of demanufacturing and remanufacturing systems

In the recent years, increasing attention has been posed towards enhancing the sustainability of manufacturing processes by reducing the consumption of resources and key materials, the energy consumption and the environmental footprint, while also increasing companies’ competitiveness in global market contexts. De- and remanufacturing includes the set of technologies/systems, tools and knowledge-based methods to recover and reuse functions and materials from industrial waste and post-consumer products, under a Circular Economy perspective. This new paradigm can potentially support the sustainability challenges in strategic manufacturing sectors, such as aeronautics, automotive, electronics, consumer goods, and mechatronics. A new generation of smart de- and remanufacturing systems showing higher levels of automation, flexibility and adaptability to changing material mixtures and values is emerging and there is a need for systematizing the existing approaches to support their operations. Such innovative de- and remanufacturing system design, management and control approaches as well as advanced technological enablers have a key role to support the Circular Economy paradigm. This paper revises system level problems, methods and tools to support this paradigm and highlights the main challenges and opportunities towards a new generation of advanced de- and remanufacturing systems.

Disposal and acquisition trends in second-hand products

Post-consumer products in waste streams, including durable and nondurable goods, represent a large portion of the municipal solid waste disposed of in landfills and incinerators in the United States. Product reuse is closely associated with waste prevention, and its promotion requires waste management policies that engage with household practices of disposal and acquisition of used goods. The aim of this study was to assess the disposal and acquisition practices of adults for selected second-hand products. A survey conducted using the Amazon Mechanical Turk online platform, aimed at understanding the preferred disposal routes selected when disposing of post-consumer products, as well as quantifying the distances traveled by discarded products from the current to the next user and identifying the methods of transportation commonly used. The acquisition practices were also investigated with the objective of identifying the main routes used by the consumer of second-hand products. Also, an association analysis was performed to recognize relationships between demographics and the selected disposal and acquisition methods, and to evaluate the existence of any relationship between consumption and purchase of second-hand products. Results from this study showed that disposal and acquisition routes varied according to the type of goods. Associations were observed between selected disposal and acquisition methods and demographics and between the decision on how to dispose of used products and how individuals acquire second-hand items. Local reuse predominated among respondents, but exchanges of second-hand products via the internet is expanding the boundaries of reuse to regional scales. The existence of preferred disposal routes and acquisition channels of second-hand products allows the recovery of reusable products in a more efficient manner and can be explored by decision makers to increase the recovery of post-consumer products.

Logística Reversa e Sustentabilidade

The Reverse Logistics is becoming increasingly important in companies and organizations, it is considered a competitive advantage by providing environmental responsibility and reducing costs of production inputs, bringing financial returns and competitiveness among other companies. Thus the aim of this study is to show how companies that adopt Reverse Logistics reutilize their post-consumer products and as it strengthens them before the country's economic situation. At the end it will be shown that Reverse Logistics is fully aligns the company's strategy and in return help in their social and environmental responsibility.

Rockwool waste in fly ash geopolymer composites

Mineral wool waste is often considered unrecyclable, due to its difficult-to-process physical composition, and potential microbial contamination in the post-consumer products. Total mineral wool waste generated in the EU is growing continuously and is currently over 2.3 Mt annually, volumetrically accounting for the largest single waste source in some landfills. Here, we take advantage of the alkali-soluble nature of the rockwool waste, and use a combined mixing and dissolution method to prepare this otherwise unusable waste for geopolymerization, with up to 33 % inclusion in the final product. This mixing and dissolution step enables sufficiently high solids content to form a castable geopolymer paste, which forms a rigid matrix and a compressive strength of 12.8 MPa, sufficient for structural applications. This is the first time mineral wool waste has been used as a geopolymer precursor. FESEM and XRD analysis of the formed products were performed to verify geopolymer formation. Using the preparation reported here, otherwise unrecyclable mineral wool waste can potentially be turned into a valuable raw material for geopolymer materials.

A novel method for material characterization of reusable products

Product reuse contributes favorably to waste management and resource recovery by diverting products from terminal disposal to second-hand urban markets. Many organizations with social mission incorporate in their activities the process of reuse, thus making valuable products available to second-hand customers through their thrift stores. Data management and product classification are an important aspect of quantitative analysis of second-hand products circulating through reuse organizations. The New York City Center for Materials Reuse has, for the last 10years, organized the reuse activities of most not for profit organizations, and collected valuable information on the strengths and weaknesses of their operations. One such finding is the casual, and inconsistent approach used by these organizations to keep a record of the level and value of the reuse efforts they undertake. This paper describes a novel methodology developed to standardize record keeping and characterize commonly reused post-consumer products by assessing the outgoing product flow from reuse organizations. The approach groups material composition of individual products into main product categories, creating a simplified method to characterize products. Furthermore, by linking product categories and material composition, the method creates a matrix to help identify the material composition of products handled by reuse organizations. As part of the methodology, whenever adequate data are not available about certain types of products, a process identified as “field characterization study” is proposed and incorporated in the implementation to develop meaningful and useful data on the weight and material composition. Finally, the method incorporates the estimation of the environmental impact of reuse using standard models available through the U.S. Environmental Protection Agency and other worldwide entities. The diversified weight and size of products poses a challenge to the statistical significance of the estimated weights. A case study is presented, illustrating how the proposed methodology can be applied to estimate environmental benefits from the sale of second-hand products in reuse organizations.

Tobacco industry responsibility for butts: a Model Tobacco Waste Act

Cigarette butts and other postconsumer products from tobacco use are the most common waste elements picked up worldwide each year during environmental cleanups. Under the environmental principle of Extended Producer...

Evaluating recyclability of fly ash reinforced polyvinyl chloride foams

Using fly ash as a reinforcing filler can be very cost effective; however, the recycling of postconsumer products containing fly ash is of a considerable concern. In this study, the recycling of processed polyvinyl chloride (PVC) foam reinforced with fly ash was investigated by evaluating the effect of regrind content (up to 40 wt%) and fly ash content (up to 20 wt%) on the physical, mechanical, microstructural, and processing properties of the composites. Experimental results show an increase in the foam density with increasing regrind and fly ash contents. The melt viscosity increased with increasing the regrind concentration; however, it dropped with increasing the fly ash content. The tensile strength increased with increasing the regrind content, indicating a good degree of gelation in the composites. Meanwhile, the charpy impact strength of the composites decreased due to the high rigidity of fly ash particles. Dynamic mechanical analysis show that the storage modulus improved with both the addition and increasing the amount of regrind, which confirmed good stress transformation between the polymer foam matrix and the fly ash particles. The polymer matrix morphology, as was determined by scanning electron microscopy (SEM), confirmed uniform foam structure even with the addition of 40 wt% regrind in the virgin PVC. J. VINYL ADDIT. TECHNOL., 24:154–161, 2018. © 2016 Society of Plastics Engineers

A decision support system to manage the quality of End-of-Life products in disassembly systems

The quality of post-consumer products is one of the major sources of uncertainty in disassembly systems. This paper develops a methodology to design disassembly lines under variability of the End-of-Life product quality, with the objective to maximize the profit. This decision support system helps to take decisions about the depth of disassembly and the organization of the disassembly system, depending on the pre-process measurement of the key quality characteristics of the product to be disassembled. The industrial benefits are demonstrated in a real industrial case focused on the remanufacturing of mechatronic parts in the automotive industry.

¿Están funcionando los programas de recolección selectiva de residuos post-consumo? Caso: percepción en Bogotá

Mediante encuestas, se evaluó la percepción que tienen los usuarios de productos post-consumo de medicamentos vencidos, computadores, bombillas, pilas y llantas en la ciudad de Bogotá como parte de los Planes de Recolección Selectiva y Gestión Ambiental de residuos que viene implementando el Ministerio de Medio Ambiente y Desarrollo Sostenible (antes Ministerio de Ambiente, Vivienda y Desarrollo Territorial) desde el año 2009 con el apoyo de la Asociación Nacional de Empresarios de Colombia (ANDI). Se evidencia un desconocimiento por parte de los consumidores de estos planes de recolección debido a la falta de información que existen entre los diferentes actores involucrados (productores, distribuidores y comercializadores) acerca del ciclo de vida de los estos productos.

Rare-earth elements recovery from post-consumer hard-disc drives

The recovery of neodymium from post-consumer products is gaining significant interest. To study the recycling feasibility of neodymium in end-of-life (EOL) computer hard disc drives (HDDs), NdFeB magnets were collected using a steel grate during commercial shredding, followed by thermal demagnetisation, grinding and screening to yield an upgraded scrap. Two metallurgical extraction routes were investigated. The first is a high temperature molten slag extraction followed by H2SO4 leaching at room temperature. Both CaO–SiO2–Al2O3 and CaO–CaF2 slag systems were tested with more than 99% rare earths recovery, but with incomplete leaching. In the second route, the upgraded scrap was directly leached to dissolve 97% rare earth content. In both cases, 98% of the rare earths in the leach solution were subsequently converted into a high purity (98·4%) rare earths double salt (NaNd(SO4)2·H2O) that can be converted to either RF3 or R2O3, the two common raw materials in the production of rare earth metals.

Value Analysis of Neodymium Content in Shredder Feed: Toward Enabling the Feasibility of Rare Earth Magnet Recycling

In order to facilitate the development of recycling technologies for rare earth magnets from postconsumer products, we present herein an analysis of the neodymium (Nd) content in shredder scrap. This waste stream has been chosen on the basis of current business practices for the recycling of steel, aluminum, and copper from cars and household appliances, which contain significant amounts of rare earth magnets. Using approximations based on literature data, we have calculated the average Nd content in the ferrous shredder product stream to be between 0.13 and 0.29 kg per ton of ferrous scrap. A value analysis considering rare earth metal prices between 2002 and 2013 provides values between $1.32 and $145 per ton of ferrous scrap for this material, if recoverable as pure Nd metal. Furthermore, we present an analysis of the content and value of other rare earths (Pr, Dy, Tb).

A novel separation process for recycling of post-consumer products

The use of automated product recycling based upon fragmentation and separation processes is rapidly increasing due to the high economic feasibility. Air-classifiers are key low-cost technologies employed in these processes; however their efficiency can be highly variable due to inhomogeneous particle sizes as separation largely relies upon the difference in particle terminal velocity. In this paper a pulsing air-column classifier is introduced in which particles are constantly accelerated and decelerated to provide higher separation efficiency regardless of particle sizes. Experimentation with inhomogeneous granulated leather, foam and rubber from footwear waste products demonstrates a separation improvement of 10–25% compared to existing technologies and ability to reclaim rubber with above 90% purity.

A Novel Approach to Recycle the Waste Plastics by Bitumen Modification for Paving Application

Recycling of waste plastics (WP) denotes an effectual method to dispose the post-consumer products for possible alternative way to obtain new materials with good properties. With this aim the influences of WP and maleic anhydride (MA) grafted WPs (MA-g-WP) were investigated as the bitumen modifiers for paving applications. Fourier transform infrared (FTIR) spectroscopy analysis established the effective grafting of MA with the waste plastic (WP). Polymer modified bitumen (PMB) binders were analyzed under scanning electron microscopy (SEM) and optical microscopy (OP) in an effort to characterize the bitumen/modifier interphase morphology. The conventional rheological tests such as penetration test, softening point, and ductility results indicate that the degree of polymer modifications are function of the nature of modifier, bitumen–modifier compatibility, and modifier concentration. It has also been confirmed that the morphology observed by SEM and optical microscopy revealed the compatibility between MA-g-WP and bitumen, and the storage stability of binder was improved significantly compared with WP modified bitumen (WPMB) binders. Consequently, the use of grafted modifier with polar site can be considered as a suitable alternation for modification of binder in pavement by expecting their chances for better performance during service.

Influence of the impact assessment method on the conclusions of a LCA study. Application to the case of a part made with virgin and recycled HDPE

Recent legislation has stressed the need to decide the best end-of-life (EoL) option for post-consumer products considering their full life-cycle and the corresponding overall environmental impacts. The life cycle assessment (LCA) technique has become a common tool to evaluate those impacts. The present study aimed to contribute to the better understanding of the application of this technique, by evaluating the influence of the selection of the life cycle impact assessment (LCIA) method in its results and conclusions. A specific case study was chosen, using previous information related to an anti-glare lamellae (AGL) for highway use, made with virgin and recycled high-density polyethylene (HDPE). Five distinct LCIA methods were used: Eco-indicator 99, CML 2 (2000), EPS 2000, Eco-indicator 95 and EDIP 97. Consistent results between these methods were obtained for the Climate change, Ozone layer depletion, Acidification and Eutrophication environmental indicators. Conversely, the Summer smog indicator showed large discrepancies between impact assessment methods. The work sheds light on the advantages inherent in using various LCIA methods when doing the LCA study of a specific product, thus evidencing complementary analysis perspectives.

Design standards for product end-of-life processing

In 2006, the British Standards Institute (BSI) published BS 8887-1 ‘Design for Manufacture, Assembly, Disassembly and End-of-life processing’ (MADE) subtitled ‘General Concepts, Processes and Requirements’. This was the first British Standard to address design for efficient post-consumer product reprocessing. By designing and planning for remanufacture, much of the embodied energy and production investment can be retrieved after the consumer no longer requires the original item. Therefore, end-of-life products become an asset rather than a liability. Design for disassembly facilitates efficient deconstruction and thus enables materials to be recycled with minimal loss of purity, thus maximising their value. The analysis presented here is based on the Standard Industrial Classification codes of companies and organisations that have purchased BS 8887-1. These data are considered in relation to the influence of environmental legislation. Company age, size and location, as well as ISO 9001 and ISO 14001 certifications, are discussed. This paper concludes by suggesting suitable directions for the continued distribution and development of this environmentally, economically and socially beneficial standard.