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Recycling, Volume 3, Issue 2 (June 2018)

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Open AccessTechnical Note Research of Chosen Acoustics Descriptors of Developed Materials from Old Automobile Recycled Materials
Received: 26 April 2018 / Revised: 6 June 2018 / Accepted: 11 June 2018 / Published: 14 June 2018
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Abstract
Legislative regulations and standards have been approved for noise control, aimed at controlling noise minimization. This problem is also under the public interest, because noise is increasing in many counties. EU directive 70/157/eec determines and controls limits of environmental noise and is aimed
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Legislative regulations and standards have been approved for noise control, aimed at controlling noise minimization. This problem is also under the public interest, because noise is increasing in many counties. EU directive 70/157/eec determines and controls limits of environmental noise and is aimed at creating less noisy and more pleasant outdoor and indoor environments for European residents within “sustainable development in Europe”. This study focused on the utilization of new, so-called acoustic more convenient materials, based on and produced from old materials from automobiles, e.g. foam, textile, rubber, and tires. The chosen acoustic parameters—sound absorption coefficient and sound transmission loss—of these materials were tested, and the acoustic properties of materials were subsequently improved compared to tested values and potential applications for them were found. Full article
(This article belongs to the Special Issue Quo Vadis Recycling 6)
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Open AccessArticle Households’ Perception of Financial Incentives in Endorsing Sustainable Waste Recycling in Nigeria
Received: 13 March 2018 / Revised: 2 May 2018 / Accepted: 31 May 2018 / Published: 13 June 2018
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Abstract
Recycling is viewed as a central aspect in sustainability and mainly as pro-environmental consumer behavior. The purpose of this study is to examine the perception of households on financial incentives in endorsing sustainable recycling for municipal solid waste in Nigeria. The study was
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Recycling is viewed as a central aspect in sustainability and mainly as pro-environmental consumer behavior. The purpose of this study is to examine the perception of households on financial incentives in endorsing sustainable recycling for municipal solid waste in Nigeria. The study was conducted in the Shomolu Local Government Area, Lagos State, Nigeria. The study also covers drivers for household willingness to recycle municipal solid waste on environmental risk, behavioral economics, resource value, economic benefit, convenience, knowledge, legislation, and belief. The result from the study asserts the hypothesis that financial incentives for recycling are vital for reducing and managing municipal solid waste sustainably. The most important driver for household willingness to recycle municipal solid waste is the detrimental environmental impacts. A moderate to positive relationship exists between households’ perception of financial incentives for recycling and drivers for household willingness to recycle municipal solid waste. The study recommends adopting the extended producer responsibility (EPR) model, reverse vending options, amongst other approaches, in an effort to promote recycling culture among citizens and residents in Nigeria. Full article
(This article belongs to the Special Issue Waste Management Education and Promotion)
Open AccessArticle Estimation of Phenolic and Flavonoid Compounds and Antioxidant Activity of Spent Coffee and Black Tea (Processing) Waste for Potential Recovery and Reuse in Sudan
Received: 3 April 2018 / Revised: 30 May 2018 / Accepted: 11 June 2018 / Published: 12 June 2018
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Abstract
This study aimed to evaluate the antioxidant power associated with spent coffee and black tea processing waste. Ethanolic extracts from the samples were prepared in order to determine the quantities/concentrations of the phenolic and flavonoid compounds, polyphenols, and associated levels of antioxidant activity.
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This study aimed to evaluate the antioxidant power associated with spent coffee and black tea processing waste. Ethanolic extracts from the samples were prepared in order to determine the quantities/concentrations of the phenolic and flavonoid compounds, polyphenols, and associated levels of antioxidant activity. The results showed that both the spent coffee and black tea waste had high amounts of phenolic compounds and high antioxidant activity rates. The total phenolic and flavonoids content was found to be significantly higher (p < 0.05) in the spent black tea than in the spent coffee. The total phenolic content was found to be 152.8 and 97.87 mg of gallic acid equivalent/g, while the total amount of flavonoids was found to be 47.40 and 34.32 mg catechin/g in spent black tea and coffee, respectively. However, the spent coffee had a significantly higher (p < 0.05) antioxidant activity than that detected in the spent black tea (57.83%). Consequently, the results revealed that the waste residue of spent coffee and black tea may be considered as natural sources of bioactive compounds and that there may be potential for recycling these waste products, which could be applied in different industries to further develop functional foods. Full article
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Open AccessArticle Investigation of Accidents during Storage Caused by Fermentation or Oxidation from SSSR and Fishmeal Using Thermal Analysis and Frank-Kamenetskii Theory
Received: 17 April 2018 / Revised: 21 May 2018 / Accepted: 31 May 2018 / Published: 2 June 2018
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Abstract
In Japan, where soy sauce production and the fishery industries thrive, soy sauce squeezing residue (SSSR) and fishmeal, which are operational byproducts of these sectors, are produced as waste materials for recycling. SSSR and fishmeal have resulted in accidents due to spontaneous ignition
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In Japan, where soy sauce production and the fishery industries thrive, soy sauce squeezing residue (SSSR) and fishmeal, which are operational byproducts of these sectors, are produced as waste materials for recycling. SSSR and fishmeal have resulted in accidents due to spontaneous ignition and oxygen deprivation, which are believed to have been caused by the heat generated through fermentation or oxidation; consequently, it is desirable to develop measures that prevent such accidents during storage and transportation. In this study, we assessed the hazards associated with the spontaneous ignition and oxygen deprivation of SSSR and fishmeal in storage areas using thermal and gas analysers, focusing on the heat produced by fermentation and oxidation. We also used Frank-Kamenetskii theory to determine the relationship between pile height and the ambient temperatures at which spontaneous ignition and oxygen deprivation occur. Our results suggest that oxygen deficiency may occur in a well-sealed storage facility in which oxygen is consumed by fermentation. For example, the oxygen concentration can drop below critical safety thresholds in the case of SSSR, even when stored below 25 °C, particularly when the moisture content is high. However, when a sufficient amount of oxygen is present and the material is stored in large deposits in a well-insulated facility, fermentation causes the temperature to increase, leading to the oxidation of fatty acid esters and eventually fire; when SSSR or fishmeal is maintained at temperatures near 40 °C, their temperatures can increase to 250 °C within approximately 30 h. Furthermore, the results of this study also demonstrate the need to consider pile height in storage areas in order to prevent accidents due to spontaneous ignition and oxygen deprivation; the critical ambient temperature at which heat accumulates is estimated to be between 20–30 °C, at a bulk density of 0.3 × 103 kg/m3, and a pile height of 3 m. Full article
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Open AccessArticle Production and Evaluation of Composite Rainwater Storage Tanks from Recycled Materials Part 2: Stored Water Quality Assessment
Received: 4 April 2018 / Revised: 22 May 2018 / Accepted: 30 May 2018 / Published: 2 June 2018
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Abstract
This paper presents the concluding part of the study on the development cement-bonded composite tanks for rainwater storage. Water containers were fabricated using four composite mixtures (cement + sawdust, cement + sawdust + water sachets, cement + sawdust + acrylic plastic waste, and
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This paper presents the concluding part of the study on the development cement-bonded composite tanks for rainwater storage. Water containers were fabricated using four composite mixtures (cement + sawdust, cement + sawdust + water sachets, cement + sawdust + acrylic plastic waste, and cement + sawdust + water sachet + acrylic plastic waste) and tested. The quality of the rainwater samples tested immediately after harvesting and samples stored in the composite tanks, a traditional clay pot and a plastic bucket (controls) for four and eight weeks, respectively, were analyzed. The cooling effects of the composite tanks on the stored rainwater were also investigated. Results indicated that the harvested rainwater was free of contaminants. However, there were some preliminary negative interactions between cement and the stored water. Within the first four weeks in storage, the water quality deteriorated with the pH and total suspended solids exceeding acceptable limits. A marked reduction in the salinity, total hardness, total dissolved solids, electrical conductivity, and turbidity was observed by the eighth week. Acrylic plastic waste particles generally had minimal negative interaction with the stored rainwater. The cooling effects of the tanks were positively correlated with the density and thermal conductivity of the composite materials. Full article
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Open AccessArticle On the Prevention of Avoidable Food Waste from Domestic Households
Received: 28 February 2018 / Revised: 30 April 2018 / Accepted: 23 May 2018 / Published: 1 June 2018
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Abstract
Unconsumed food impacts on the environment via the wasteful use of resources in its production and via its disposal. Householders would ideally only generate food waste that is not considered edible (unavoidable food waste) and the disposal of edible food (avoidable food waste)
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Unconsumed food impacts on the environment via the wasteful use of resources in its production and via its disposal. Householders would ideally only generate food waste that is not considered edible (unavoidable food waste) and the disposal of edible food (avoidable food waste) would be prevented, mitigating both the environmental impacts of food waste and reducing consumers’ wasted expenditure on uneaten food. This study aimed to elucidate if and how householders’ food waste behaviour might be changed via interventions in the form of a leaflet highlighting the impacts of avoidable food waste. The composition of avoidable food waste set out for kerbside collection was assessed in relation to interventions intended to reduce avoidable food waste and in relation to households’ economic status. Two parallel interventions were tested, setting out to householders the impacts of avoidable food waste on (1) the environment, and (2) personal finances. Avoidable food waste set out by affluent and low income households, considered in terms of total weight, life-cycle stage and product group, did not change significantly after delivery of either leaflet. Neither of the interventions tested had a discernible impact on the quantity and composition of avoidable food waste in these terms. We propose that initiatives to reduce food waste may be more successful if focused on positive actions to improve householders’ efficiency in their food use, directed by insight provided by analysis of avoidable food waste within product groups and in relation to life-cycle stage. Full article
Open AccessArticle Production and Evaluation of Composite Rainwater Storage Tanks from Recycled Materials Part 1: Material Characterization
Received: 4 April 2018 / Revised: 15 May 2018 / Accepted: 18 May 2018 / Published: 21 May 2018
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Abstract
Solid waste management and potable water supply are two of the major challenges in Nigeria. Recycling of wood and plastic wastes as cement-bonded composite rainwater storage tanks can play a major role in addressing both challenges. The aim of this study was to
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Solid waste management and potable water supply are two of the major challenges in Nigeria. Recycling of wood and plastic wastes as cement-bonded composite rainwater storage tanks can play a major role in addressing both challenges. The aim of this study was to determine acceptable composite formulations for tank production and their short-term effects on stored rainwater. This paper reports the experimental results on composite formulations using varying proportions of Gmelina arborea sawdust, water sachet and acrylic plastic waste and determining their moisture content, density, water absorption (WA), thickness swelling (TS), thermal conductivity (TC), and impact energy. The moisture contents (14.7–16.5%) and densities (1.24–1.53 g/m3) exceeded the minimum value specified for cement-bonded composites. WA in all samples containing plastic materials were relatively low (<6%), an indication of suitability for water storage. However, only the samples containing water sachet exhibited an acceptable thickness swelling (approximately 2%). Density and WA had positive correlations with TS of the composites. The TC values (0.044–0.051 W/mK) were acceptably low. A strong, positive linear correlation was also observed between density and TC. Samples produced with a combination of cement, sawdust, water sachet and acrylic plastic exhibited the highest impact energy. Full article
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Open AccessCommunication Recycling within the Chemical Industry: The Circular Economy Era
Received: 6 April 2018 / Revised: 4 May 2018 / Accepted: 11 May 2018 / Published: 19 May 2018
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Abstract
In this present work, we have briefly discussed the importance of recycling within the chemical sector. Recycling is fundamental in promoting a circular economy, which is a new paradigm of sustainability that is able to reduce environmental implications, and in creating new business
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In this present work, we have briefly discussed the importance of recycling within the chemical sector. Recycling is fundamental in promoting a circular economy, which is a new paradigm of sustainability that is able to reduce environmental implications, and in creating new business opportunities. Therefore, to highlight the importance of recycling in the circular economy era, we have reported on some recent examples of strategies helpful to minimize waste by increasing the efficiency of the whole system and promoting a greener/safer chemical industry. Full article
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Open AccessArticle Improving the Energy Concentration in Waste Printed Circuit Boards Using Gravity Separation
Received: 5 April 2018 / Revised: 8 May 2018 / Accepted: 11 May 2018 / Published: 16 May 2018
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Abstract
Electronic waste is one the fastest growing waste streams in the world, and printed circuit boards (PCBs) are the most valuable fraction of this stream due to the presence of gold, silver, copper, and palladium. Printed circuit boards consist of approximately 30% metals
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Electronic waste is one the fastest growing waste streams in the world, and printed circuit boards (PCBs) are the most valuable fraction of this stream due to the presence of gold, silver, copper, and palladium. Printed circuit boards consist of approximately 30% metals and 70% non-metals. The non-metal fraction (NMF) is composed of 60–65% fiberglass and 35–40% organics, in the form of surface-mount plastics and epoxy resins in the printed circuit board laminates. The organics in the NMF provide a potential alternative source of energy, but hazardous flame retardants contained in epoxy resins and the presence of residual metals create challenges for utilizing this material for energy recovery. This research provides an evaluation of the energy content of printed circuit boards. Density-based separation was used to separate various components of the NMF to increase the energy content in specific density fractions while reducing the metal content. The result showed that the energy content before and after the removal of the metallic fraction from PCBs was 9 and 15 GJ/t, respectively. After the density-based separation of the NMF, the energy content in the lightest fraction increased to 21 GJ/t, while reducing the concentration of the hazardous flame retardants. The contents of the hazardous flame retardants and residual metal were analyzed, to evaluate the harmful effect of emissions produced from utilizing the NMF as an alternative feedstock in waste-to-energy applications. Full article
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Open AccessArticle Skateboards as a Sustainable Recyclable Material
Received: 25 April 2018 / Revised: 11 May 2018 / Accepted: 11 May 2018 / Published: 15 May 2018
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Abstract
The exact number of skateboards manufactured every year is unknown, but it is estimated to be in the millions. Most skateboard decks are made from a high grade of maple (Acer spp.) veneer plywood and typically last only a few months before they
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The exact number of skateboards manufactured every year is unknown, but it is estimated to be in the millions. Most skateboard decks are made from a high grade of maple (Acer spp.) veneer plywood and typically last only a few months before they break or deteriorate beyond use. Millions of used skateboard decks are discarded annually, ending up in landfills when, instead, they could be recycled into new products. But beyond artistic or aesthetic purposes, material properties of the used skateboard decks are unknown. The objective of this paper is to investigate the material properties of wooden composite panels created by reengineering the skateboard deck material. These aesthetically pleasing wooden panels may be a sustainable recycled product. This paper presents a method of analyzing material properties and structural aspects of used skateboard deck material. Tests were developed to measure the stiffness and strength in bending, moisture content, specific gravity, moisture durability, and species identification. The results show that this process of reengineering skateboard decks makes for a strong wood product and may be useful to those interested in developing new products from recycled materials. Full article
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Open AccessArticle Municipal Solid Waste Management in Latin America and the Caribbean: Issues and Potential Solutions from the Governance Perspective
Received: 23 March 2018 / Revised: 26 April 2018 / Accepted: 9 May 2018 / Published: 10 May 2018
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Abstract
Municipal Solid Waste (MSW) management is an essential service for an urban population to maintain sanitation. Managing MSW is complex as the treatment/recovery options depend not only on the volume of waste, but also on the socioeconomic conditions of the population. This paper
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Municipal Solid Waste (MSW) management is an essential service for an urban population to maintain sanitation. Managing MSW is complex as the treatment/recovery options depend not only on the volume of waste, but also on the socioeconomic conditions of the population. This paper focusses on MSW management in the Latin American and Caribbean (LAC) countries. Dominance of uncontrolled disposal options of MSW in the region, such as open dumps, has an adverse influence on health and sanitation. Interest in source separation practices and recycling is low in the LAC region. Furthermore, economic matters such as poor financial planning and ineffective billing systems also hinder service sustainability. Rapid urbanization is another characteristic feature in the region. The large urban centres that accommodate over 80% of the region’s population pose their own challenges to MSW management. However, the same large volume of MSW generated can become a steady supply of resources, if recovery options are prioritized. Governance is one aspect that binds many activities and stakeholders involved in MSW management. This manuscript describes how we may look at MSW management in LAC from the governance perspective. The issues, as well as the best potential solutions, are both described within three categories of governance: bureaucratic, market, and network. The governance perspective can assist by explaining which stakeholders are involved and who should be responsible for what. Financial issues are the major setbacks observed in the bureaucratic governance institutions that can be reversed with better billing strategies. MSW is still not seen by the private sector as a place to make investments, perhaps due to the negative social attitude associated with waste. The market governance aspects may help increase the efficiency and profitability of the MSW market. Private sector initiatives such as cost-effective microenterprises should be encouraged and the projects that fit under the Clean Development Mechanism (CDM) defined in the Kyoto Protocol should be incentivized to attract technology and capital. Lastly, network governance is at the centre of attention due to its flexibility in supporting/absorbing public-private partnerships, especially the participation of the informal sector that is important to the LAC region. Many individual waste pickers are providing their services to the LAC region by taking part in collecting and recycling under very unfavourable working conditions. Full article
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Open AccessFeature PaperArticle Managing Cd Containing Waste—Caught by the Past, the Circular Economy Needs New Answers
Received: 18 December 2017 / Revised: 11 April 2018 / Accepted: 3 May 2018 / Published: 8 May 2018
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Abstract
What is understood by the circular economy concept is the re-use and recycling of used materials and waste. In many used products, hazardous compounds are found or might be present either because of the products’ present intended use or former applications that have
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What is understood by the circular economy concept is the re-use and recycling of used materials and waste. In many used products, hazardous compounds are found or might be present either because of the products’ present intended use or former applications that have been banned in the meantime. Clearly, recycling activities should not endanger man and environment through carryover of contaminants. To learn more about how hazardous chemicals in waste impede the circular economy, it is necessary to investigate the ways in which products containing hazardous compounds have been handled up to now in order to avoid secondary contamination. For this study, cadmium (Cd) in NiCd batteries and accumulators and Cd compounds used as stabilisers for PVC profiles were selected as examples. The situation in the European Union was analysed, with a focus on legislation, collection, recycling, disposal and the further fate of “co-recycled” Cd. Insufficient collection rates, partially unsafe disposal and carryover were identified as the main problems. An advanced management strategy for Cd and its compounds is needed in order to mitigate problems in the circular economy. Used products containing hazardous substances ought to be recycled without contaminating the environment or recycled materials. The results suggest that circular economy is faced with different, partially insurmountable challenges. Full article
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Open AccessArticle Manufacturing a Better Planet: Challenges Arising from the Gap between the Best Intentions and Social Realities
Received: 1 January 2018 / Revised: 19 April 2018 / Accepted: 27 April 2018 / Published: 3 May 2018
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Abstract
With rising concerns about the social and environmental impacts of industrial and manufacturing waste, scientists and engineers have sought solutions to the burdens of waste which do not simply involve burying, burning, dumping or diluting. Our purpose here is to sketch how social
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With rising concerns about the social and environmental impacts of industrial and manufacturing waste, scientists and engineers have sought solutions to the burdens of waste which do not simply involve burying, burning, dumping or diluting. Our purpose here is to sketch how social science perspectives can illuminate aspects of the waste problem which are not routinely grappled with within science and engineering perspectives. We argue that if one is concerned about the burdens of waste, it is crucial to understand the way political and cultural contexts shape what happens (or does not happen) in regards to reuse. We sketch some of the challenges facing green manufacturing; challenges that hinge on the gap between the best laid plans and social realities. Rather than imply green manufacturing is simply a post hoc move to hide the excesses of industrial capitalism in the green cloth of sustainability, we hope our discussion can assist those who hope to use green manufacturing as a pre-emptive move to build sustainability into industrial capitalism. We suggest that a socio-political conception of technology can bring greater depth to understandings of the industrial, political and consumer environments into which green manufacturing researchers hope to insert their efforts. Full article
Open AccessArticle Key Drivers for High-Grade Recycling under Constrained Conditions
Received: 1 April 2018 / Revised: 24 April 2018 / Accepted: 24 April 2018 / Published: 28 April 2018
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Abstract
Various authors have analyzed the fundamental barriers that hamper the transition towards a circular economy, e.g., economic and business, regulatory and legal, and social. This analysis questions how, under these constrained conditions, high-grade recycling can still be implemented successfully in the Netherlands. The
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Various authors have analyzed the fundamental barriers that hamper the transition towards a circular economy, e.g., economic and business, regulatory and legal, and social. This analysis questions how, under these constrained conditions, high-grade recycling can still be implemented successfully in the Netherlands. The study compares five Dutch material flows: paper and cardboard, plastics, non-wearable textiles, building and demolition waste and mattresses. It is concluded that the following four key conditions should be in place, but need a tailor-made approach for each material flow: (1) adequate collection system/logistics; (2) guaranteed volumes of material supply; (3) clear market demand for and (4) quality guarantee of recycled materials. Moreover, the following five key drivers help circumvent the fundamental barriers and realize the four key conditions: (1) mobilizing power by change agents; (2) cooperation within the material chain; (3) well-attuned financial arrangement; (4) circular procurement; and (5) technological innovation (including redesign). These drivers follow a certain sequence in implementation and circumvent the fundamental barriers each in their own way. This empirical analysis complements the mostly conceptual or theoretical literature on the transition towards high-grade recycling and the circular economy in general. Based on this analysis a conceptual model is developed, in which the key conditions, the key drivers and fundamental barriers are linked. Whether the results also hold true for other countries than the Netherlands needs additional research. Full article
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Open AccessArticle A Green Extraction Process to Recover Polyphenols from Byproducts of Hemp Oil Processing
Received: 28 March 2018 / Revised: 18 April 2018 / Accepted: 19 April 2018 / Published: 22 April 2018
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Abstract
The valorization of solid waste hemp (Cannabis sativa L.) by a non-conventional method is presented in this article. Hemp polyphenols were extracted using aqueous solutions of 2-hydroxypropyl-β-cyclodextrin as an eco-friendly extraction solvent. Cyclodextrins (CD’s) are known to enhance the extraction of polyphenols
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The valorization of solid waste hemp (Cannabis sativa L.) by a non-conventional method is presented in this article. Hemp polyphenols were extracted using aqueous solutions of 2-hydroxypropyl-β-cyclodextrin as an eco-friendly extraction solvent. Cyclodextrins (CD’s) are known to enhance the extraction of polyphenols in water by forming water soluble inclusion complexes. The process was optimized by implementing a response surface methodology (RSM) that took into consideration the following independent variables: CD concentration (CCD), solid-to-liquid ratio (S/L), and temperature (T). The assessment of the extraction model was based on two responses: the total polyphenol yield (YTP) and the antiradical activity (AAR). The optimum operating conditions were found to be: CD concentration, 32.1% (w/v); solid/solvent ratio, 1/15.2 g/mL; and extraction temperature, 28 °C. Different kinetic models were employed to fit with experimental data and the Peleg’s model was successfully developed for describing the mechanism of extraction under different processing parameters. Full article
(This article belongs to the Special Issue Food Waste – Strategies to Reuse and Prevention)
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Open AccessArticle The Recycling Potential of Submersible Sewage Pumps in the EU
Received: 24 March 2018 / Revised: 11 April 2018 / Accepted: 19 April 2018 / Published: 22 April 2018
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Abstract
Sewage pumps have been among the main electromechanical equipment of the sewage and wastewater management facilities around Europe for over 30 years. Their operational life ranges between 15 and 20 years. Therefore, a significant proportion of that equipment is currently non-operational, and many
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Sewage pumps have been among the main electromechanical equipment of the sewage and wastewater management facilities around Europe for over 30 years. Their operational life ranges between 15 and 20 years. Therefore, a significant proportion of that equipment is currently non-operational, and many of them must be disposed of in the forthcoming years. Although the “Waste electrical and electronic equipment” Directive (2012/19/EU) is the main related legislation, sewage pumps are not directly addressed. EcoDesign Legislation is the main legislation applicable on such cases. This work investigates the possibilities of recycling sewage pumps used in wastewater management facilities after their renovation or upgrade. Evaluation results indicate that there is high potential for material recovery and for significant economic benefit. Therefore, the recovery of materials and safe handling of non-operating industrial and possibly hazardous electrical equipment waste, could contribute to the minimization of their impact on the environment. Full article
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Open AccessFeature PaperArticle Benchmark Comparison of High Voltage Discharge Separation of Photovoltaic Modules by Electrohydraulic and Electrodynamic Fragmentation
Received: 4 December 2017 / Revised: 9 April 2018 / Accepted: 9 April 2018 / Published: 10 April 2018
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Abstract
Recent years have seen an increasing interest in exploring alternative techniques to conventional grinding methods such as fragmentation by high voltage discharges. Although pulsed power has already been applied to break down complex composite materials, there is currently no systematic comparison between different
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Recent years have seen an increasing interest in exploring alternative techniques to conventional grinding methods such as fragmentation by high voltage discharges. Although pulsed power has already been applied to break down complex composite materials, there is currently no systematic comparison between different types of discharge regimes such as electrohydraulic and electrodynamic fragmentation. The aim of this work is to present such a comparison based on the electrohydraulic and electrodynamic fragmentation of copper indium diselenide (CIS) photovoltaic modules for potential indium recovery. High voltage discharges are performed in a process vessel filled with demineralized water at ambient conditions. After fragmentation, individual fractions are weighed, milled and the indium content is determined by X-ray fluorescence (XRF). Both the electrohydraulic and the electrodynamic approach are suitable to efficiently separate thin-film photovoltaic composite material into its constituent layers. The separation result is not dependent on the voltage level, but only on the total pulse energy applied. Since the generation of discharges with higher voltages requires a higher investment into plant properties such as insulation and generator, a comminution at lower voltages, i.e., electrohydraulic fragmentation, is preferable to electrodynamic fragmentation at higher voltages. To reveal the specific strengths of the two processes compared here, further comparative work with different composite materials is required. Full article
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Open AccessArticle Upgrading of Mixed Food Industry Side-Streams by Solid-State Fermentation with P. ostreatus
Received: 6 February 2018 / Revised: 18 March 2018 / Accepted: 28 March 2018 / Published: 1 April 2018
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Abstract
In the frame of efforts to exploit agroindustrial side-streams and wastes (AISS) for added-value products that are based on single cell protein (SCP), mixed substrates consisting of brewer’s spent grains (BSG), malt spent rootlets (MSR), cheese whey, molasses, orange, and potato pulps, were
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In the frame of efforts to exploit agroindustrial side-streams and wastes (AISS) for added-value products that are based on single cell protein (SCP), mixed substrates consisting of brewer’s spent grains (BSG), malt spent rootlets (MSR), cheese whey, molasses, orange, and potato pulps, were used for growth of the edible mushroom Pleurotus ostreatus. The substrates were mixed in various combinations, and were used for P. ostreatus growth at various conditions. The substrate, for which the highest sugar consumption, protein increase, and mycelium yield were observed, consisted of 20 mL molasses (4° Baume density), 20 mL potato pulp, 5 mL whey, 5 mL orange pulp, 30 g BSG, and 5 g MSR (at 25 °C and substrate pH 4). The mycelium-enriched product was analyzed for protein, fat, minerals (Ca, Mg, Fe, Cu), and aroma volatile compounds, indicating the potential for use as nutritious supplement for food, feed, or microbiology uses. The product was also autolyzed, freeze-dried, powdered, and analyzed for total ribonucleic acid content, showing the potential for use as a commercial natural food flavor enhancer. Full article
(This article belongs to the Special Issue Food Waste – Strategies to Reuse and Prevention)
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Open AccessArticle Potential of Briquetting as a Waste-Management Option for Handling Market-Generated Vegetable Waste in Port Harcourt, Nigeria
Received: 8 March 2018 / Revised: 22 March 2018 / Accepted: 27 March 2018 / Published: 28 March 2018
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Abstract
The conversion of biomass to high-density briquettes is a potential solution to solid waste problems as well as to a high dependence on fuel wood in developing countries. In this study, the potential of converting vegetable waste to briquettes using waste paper as
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The conversion of biomass to high-density briquettes is a potential solution to solid waste problems as well as to a high dependence on fuel wood in developing countries. In this study, the potential of converting vegetable waste to briquettes using waste paper as a binder was investigated. A sample size of 30 respondents was interviewed using a self-administered questionnaire at the D-line fruit and vegetable market in Port Harcourt, Nigeria. Carrot and cabbage leaves were selected for briquetting based on their availability and heating value. This waste was sun-dried, pulverized, torrefied and fermented. Briquettes were produced with a manual briquette press after the processed vegetable waste was mixed with waste paper in four paper:waste ratios, i.e., 10:90, 15:85, 20:80 and 25:75. The moisture content, densities and cooking efficiency of the briquettes were determined using the oven-drying method, the water-displacement method, and the water-boiling test, respectively. There was no observed trend in moisture content values of the briquettes, which varied significantly between 3.0% and 8.5%. There was no significant variation in the densities, which ranged from 0.79 g/cm3 to 0.96 g/cm3 for all the briquette types. A degree of compaction above 300% was achieved for all the briquette types. Water-boiling test results revealed that 10:90 paper:sun-dried cabbage briquettes had the highest ignitability of 0.32 min. Torrefied carrot briquettes with 25% paper had the least boiling time and the highest burning rates of 9.21 min and 4.89 g/min, respectively. It was concluded that cabbage and carrot waste can best be converted into good-quality briquettes after torrefaction. Full article
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