Current Recycling Research Articles

Recycling sustainability of waste paper industry in Beijing City: An analysis based on value chain and GIS model

China established a self-organized and market-driven recycling system, which was dominated by the informal sectors. In recent years, the amount of domestically-recycled waste paper grew slower than expectation in China, which may be resulted from a decline in economic sustainability of current recycling system. For understanding the waste paper recycling system in most cities in China, the economic mechanism remains unclear and the city-level data is extremely insufficient. In this work, an index of recycling sustainability (IRS, benefit divided by cost) is analyzed with a resolution of 1 km2 grid in Beijing City, by adopting value chain and GIS methodology. Five degrees of IRS are defined, from high-degree (IRS > 1.10) to low-degree (IRS < 0.95). Different stakeholders in the informal waste paper recycling system were interviewed to fill the data gap. Results show that: (1) from 2015 to 2018, the informal recycling of waste paper accounted for approximate 80% in Beijing; (2) the number of informal recyclables distribution sites decreased from 27 to 11, and their average distance to the city-center rose from 27.5 km to 40.9 km; (3) in 2015 and 2018, the grids with high-degree IRS accounted for 99.5% and 89.2%, respectively, indicating a sustainable waste paper recycling industry in Beijing; and (4) according to the scenario analysis, if the operating cost rises by 30%, the grids with low-degree IRS accounts for 98.5%, indicating a nontrivial challenges when the recycling cost keeps increasing in the future. Policy recommendations are put forward for a more sustainable paper waste recycling system in China.

EVALUATION OF NETWORKS BETWEEN PRODUCTION UNITS IN THE POST-CONSUMER PET PACKAGING RECYCLING CHAIN

This study aimed to evaluate recycling networks for poly(ethylene terephthalate) (PET) packaging and propose a network structure for sharing recycling routes between different production units, using the Rio de Janeiro metropolitan region as a case study. A descriptive design was used and field research conducted to gather data on the recycling process. Participants were production units, classified as distributors, distribution recyclers, intermediate recyclers, and molding recyclers. A georeferencing program established the location of these units, origin of the PET waste, its distribution, and the structure of integration networks between recycling units considering the supplier-customer relationship, in order to assess the reverse logistics of post-consumer PET. The data obtained were analyzed qualitatively and quantitatively to elucidate the current recycling scenario and propose a new network structure. The proposed framework would reduce the distances traveled by almost 50%, while maintaining the same business relationships between the production units identified. The most prominent features of the current recycling structure are that PET distributors are located near their suppliers, whereas intermediate-recyclers are close to molding-recyclers, their customers.

Life Cycle Analysis of AA Alkaline Batteries

From energy and CO2 footprint perspectives, this study focuses on the Life Cycle Analysis (LCA) of AA alkaline batteries considering options other than landfill namely downcycling or, more ambitiously, recycling/remanufacturing. With the exception of lead-acid batteries that are recycled intensively in an energy-efficient manner, many types of batteries are not recycled and are disposed of via traditional disposal routes. Currently, there is lack of economical incentive given that available processes used in recycling batteries to reclaim metals require 6-10 times more energy than extracting/refining those metals from ores. Some processes (e.g., pyrometallurgical) require large capital investment and use large amounts of energy. For AA batteries, current recycling techniques involve 1) burning off the plastic wrapper, 2) batteries are shredded, and 3) melted where metals segregate into layers according to their respective densities, and 4) each molten metal layer is then collected.This study addresses the feasibility of recycling alkaline batteries, as they are the most common dry batteries as well as being more benign as compared with other types such as lithium-ion or Ni-cadmium. From energy and CO2 footprint perspectives, this study makes a case for downcycling or even recycling/remanufacturing (depending on the material of the separated components) for the zinc metal, manganese oxide concentrates, and other components for recycling/reuse in an efficient/environmentally-friendly manner. Life cycle analysis (LCA) findings suggest that, if technology is developed so that the cathode and anode materials are recycled/reused, there will be significant recovered energy and CO2 values. For a world annual production estimate of 4 billion AA alkaline batteries, the EOL potential findings estimate energy savings and CO2 footprint reduction of about 6.2*1015 J and 3.75*108CO2 kg, respectively.

A Complementary Recycling Operational Transconductance Amplifier with Data-Driven Enhancement of Transconductance

An improved operational transconductance amplifier (OTA) is presented in this work. The fully differential OTA adopts the current recycling technique and complementary NMOS and PMOS input branches to enhance the total transconductance. Moreover, in order to achieve higher current efficiency, a data-driven biasing circuit was developed to dynamically adjust the power consumption of the amplifier. Two comparators were added to detect the voltage difference at the input nodes, and when the differential input is large enough to activate either comparator, extra biasing current is activated and poured into the amplifier to enhance its slew rate and gain-bandwidth product (GBW). The threshold voltage of the complementary recycling folded cascode (CRFC)-based comparator is configured to suppress overshoot. Complementary common-mode feedback (CMFB) topology with local CMFB structure is built to acquire high common-mode gain. The OTA was fabricated in SMIC 0.18- μ m CMOS technology. The experimental result based on a capacitive feedback loop shows that the data-driven operation improves the average slew rate of the amplifier from 10.2 V/ μ s to 55.5 V/ μ s while the power only increases by 150%. The OTA has good potential to satisfy the fast settling demands for capacitive sensing circuits.

A material and component bank to facilitate material recycling and component reuse for a sustainable construction: concept and preliminary study

This paper concerns the reusable components and recycled materials from demounted structures which may draw a large amount of waste in construction industry. By a series of literature review and analyses, a material and component bank was proposed to manage more effectively the recycling of materials and direct reuse of components even of whole components obtained from old structures to facilitate a more sustainable construction industry. The concept, main businesses, and work operation of the bank were illustrated in detail including its potential management method and supply chain. The relationship between the bank and current building information modeling, design for deconstruction, supply chain, and life cycle assessment based on the bank were then analyzed in detail. It can be concluded that the bank could pave the way for effectively performing a further and repaid reuse of components and perfecting current recycling of materials to contribute a more sustainable built environment from the view of various terms mentioned in this study. The bank also can link with current method of life cycle assessment or environmental impact assessment well, which all can promote the construction sustainability indicating the bank can be integrated into current construction industry easily for the future.

Recycling fund management for a cleaner environment through differentiated subsidy rates

Abstract This study investigates recycling fund management via differentiated subsidy rates to help encourage greater effort for a cleaner environment. The Recycling Fund Management Board in Taiwan targets the environmental goal of maximizing the total recycling rate through a subsidy to the recycling industry. The industry aims to maximize its profits and is expected to use advanced technology for an environmental friendly process in order to obtain a higher subsidy rate, and it potentially exploits other instruments to increase the return rate from consumers as well. This research establishes recycling fund management and trade-off models and analyzes both goals within the realm of Taiwan's fund management of waste printers. The results show that a differentiated rate is worth executing under enough funds, but could be hard to achieve with the input of the current recycling and treatment fee and the subsidy rate. Since few subsidies have a negative impact on the return rate, the board can consider raising the fee. To reach an ultimate environmental goal of “cradle to cradle”, enough industry profits are required for improving the quality of the recycling process and providing more rewards to consumers. We recommend that the board take a further step at utilizing a differentiated rate and raising the fee to balance the long-term goals of fund management.

Current Recycling: New Results

Long ago, current recycling or serial biasing technique was recognized as a promising solution for the reduction of bias current in VLSI dc biased digital superconductor circuits. Despite a significant number of declarations, not so many successful experiments have been reported so far. In the paper we discuss our recent experiments with serially biased 16-bit counter-flow RSFQ shift registers, connected by special interfaces that are able to transfer SFQ pulses between the galvanically isolated driver and receiver. The required functionality is achieved using a superconductor transformer with isolated input and output coils. The known drawback of such interfaces is their parasitic sensitivity to magnetic fields induced by remote currents. To depress this sensitivity we have implemented a special superconductor guard that uses six superconductor layers. We have achieved stable operations of such registers with 16 current recycling stacks. The circuits have been fabricated at MIT Lincoln Laboratory.

IoT recycle management system to support green city initiatives

&lt;p&gt;In July 2009, Government of Malaysia had launched Green Technology Policy as new initiatives from Malaysia to handle greenhouse effect issue and energy usage through application and green technologies development to reduce carbon footprint. This project, Internet of Things (IoT) Recycle Management System is an idea to help the government in gearing the nation towards this aim with a developed system or technology that support green environment. For this paper, the intended cities are Putrajaya and Cyberjaya areas since both of these cities are chosen as a pioneer for the Green City Initiatives by the Government. This Arduino based Internet of Things (IoT) project is an upcoming urban technology that transforms everyday current recycling system into an ecosystem that would enrich our lives and make it exciting to recycle things anywhere. Hence, encourages Malaysian to recycle their things regularly and make it as a normal routine. This project consists of the development of recycle waste bin that have sensor-based and a database with webpage system for client interface which be connected via Internet network. This project has a huge prospect to be implemented in the future, should there be a collaboration with Government entities and Non- Government entities as this effort needs huge support from all Malaysians in order to realize first class mentality transformation.&lt;/p&gt;

ERSFQ 8-Bit Parallel Arithmetic Logic Unit

We have designed and tested a parallel 8-bit ERSFQ arithmetic logic unit (ALU). The ALU design employs wave-pipelined instruction execution and features modular bit-slice architecture that is easily extendable to any number of bits and adaptable to current recycling. A carry signal synchronized with an asynchronous instruction propagation provides the wave-pipeline operation of the ALU. The ALU instruction set consists of 14 arithmetical and logical instructions. It has been designed and simulated for operation up to a 10 GHz clock rate at the 10-kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> fabrication process. The ALU is embedded into a shift-register-based high-frequency testbed with on-chip clock generator to allow for comprehensive high frequency testing for all possible operands. The 8-bit ERSFQ ALU, comprising 6840 Josephson junctions, has been fabricated with MIT Lincoln Lab's 10-kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> SFQ5ee fabrication process featuring eight Nb wiring layers and a high-kinetic inductance layer needed for ERSFQ technology. We evaluated the bias margins for all instructions and various operands at both low and high frequency clock. At low frequency, clock and all instruction propagation through ALU were observed with bias margins of +/-11% and +/-9%, respectively. Also at low speed, the ALU exhibited correct functionality for all arithmetical and logical instructions with +/-6% bias margins. We tested the 8-bit ALU for all instructions up to 2.8 GHz clock frequency.

Closing the loop for PET, PE and PP waste from households: Influence of material properties and product design for plastic recycling

Recycling of plastic is an important step towards circular economy. However, plastic from household waste (HHW) is a heterogeneous and contaminated resource, leading to recycled plastic with reduced quality, limiting the potential for closed-loop recycling. In addition to regulatory requirements for the chemical composition of recycled plastic, reduced physical and mechanical properties may limit the potential for closed-loop recycling. Consequently, this study analyses the thermal degradation, processability and mechanical properties of a range of reprocessed PET, PE and PP samples from source-separated plastic in HHW. On this basis, the potential for closed-loop recycling is evaluated. The study demonstrated that PET, PE and PP recycling represent different challenges. Potential degradation of the PET polymer can be reversed in a decontamination process, making PET waste well-suited for closed-loop, multiple times recycling, even when the degree of heterogeneity in the waste is high. The processability of different kinds of PE and PP packaging types varied considerably, especially for PP. Consequently, current recycling of mixed PP waste and even separate recycling of individual PP waste packaging types, will not technically facilitate recycling into new packaging products. This highlights the importance of PE and PP waste homogeneity when sent to reprocessing. Such homogeneity may be achieved through additional plastic sorting and regulatory harmonisation of product design, accounting for polymer properties and recyclability. Degradation of PP during recycling was shown to be substantial, representing another important limitation for PP recycling, necessary to address in the future.

Recycling and substitution of light rare earth elements, cerium, lanthanum, neodymium, and praseodymium from end-of-life applications - A review

The light rare earth elements (LREEs) lanthanum, cerium, neodymium and praseodymium are increasingly used in renewable energy technology and are applicable in portable electronic devices, such as phosphors in lightning applications and in catalysis. The extraction of REEs from virgin ores causes environmental degradation. LREEs are considered as critical metals. To overcome the environmental and criticality challenges of LREEs, recycling presents means by which they can be obtained from secondary sources. Presently, the recycling rate of LREEs is still very low. Substitutes of LREEs in most cases are either inferior or still undiscovered. This study investigates the criticality challenges and environmental impacts of producing LREEs from virgin ores. It focuses on LREEs obtainable in selected end-of-life products considered to have significant recycling potential; these include NdFeB magnets, Ni-MH batteries, phosphors in lighting and catalysts. Current recycling technologies, including representative methods and current recycling challenges are also reviewed. Although current recycling technologies have recorded growth, there is still a need for further improvements. The article highlights current LREEs substitution advances and the faced challenges in finding suitable LREEs substitutes. Furthermore, future ways to promote sustainability of LREEs recycling, to improve substitution, and to tackle the criticality challenges of LREEs are proposed.

Recycling and reuse of composite materials for wind turbine blades: An overview

Based on the increasing number of end of life wind turbine blades and the emphasis on resource conservation and environmental protection, more and more attention has been paid to the recycling and reuse of thermoset composite materials for wind turbine blades. This paper gives an overview of the main recycling technologies and reuse of recycled products. Current recycling technology still needs more work to move from laboratory stage to commercial production. Cheaper, less polluting, and more efficient recycling technologies are needed, along with remanufacturing technologies for high performance products can be obtained to expand the market for recycled materials. In addition, new environmentally friendly blade materials should be designed from the source, using natural fiber, modified thermosetting resin and recyclable thermoplastic resin, which make wind energy a truly clean energy.

Economic and Environmental Evaluation of Aluminium Recycling based on a Belgian Case Study

Abstract The increasing demand for aluminium (Al) has led to the significant growth of secondary Al production. Although Al is one of the most recycled metal streams, the presence of impurities, such as iron, silicon and copper, has limited the environmental and economic benefits of recycling Al. These competing interests have led to the choice of recycling options that is suboptimal. This paper evaluates the economic and environmental effects of recycling different Al scrap qualities based on data collected from a Belgian recycling facility. Observations from the case study show that the profit-driven recycling market has led to a recycling system that does not produce the best environmental impact outcome. Maximising the environmental benefits of material recycling is often secondary to profit generation from the recyclers’ perspective. There is a need for stricter measures, such as environmental tax on primary Al production, to address the environmental and economic challenges in the current recycling systems.

Sustainable solid waste management system using multi-objective decision-making model: a method for maximizing social acceptance in Hoi An city, Vietnam.

The main aim of this study was to develop a decision support system for sustainable municipal solid waste management (MSWM) in Hoi An city (HAC), Vietnam. A face-to-face interview was conducted with local experts including authorities, citizens, waste collection contractors and recyclers to identify main objectives of waste management system and appropriate treatment methods. A multi-objective optimization model was proposed using non-linear programming approach. An interactive method known as reference point method (RPM) was applied for solving the problem with three objectives including cost minimization, landfill minimization and emission minimization. As a result, the efficient waste-flow-allocation and the optimal capacity of disposal facilities were determined by intense discussion and agreement among decision-makers. Waste incineration, anaerobic digestion, sanitary landfill and current recycling activities should be applied with a cost of about 2300 US$ daily. Also, the daily emission of various pollutants was about 35 metric tons, and the greenhouse gas (GHG) is 313 tons CO2-eq.

Electronic Waste Recycling at Agbogbloshie, Ghana: A Global Problem, Current Intervention Strategies and Local Solutions

The quantity of electronic waste (e-waste) generated around the globe is expected to increase with rising economies in Asia, Latin America and Eastern Europe largely as a consequence of the introduction of new products with shorter lifespan. Current global estimates of annual e-waste production exceed 40 million tons with an annual growth rate of 4 to 5 percent. However, in spite of the increased generation, there is a current lack of an efficient, safe and sustainable infrastructure for its disposal in many regions of the world; where a majority of the materials in the global e-waste stream ends up as final destination. A typical site in Ghana where the e-waste is received and recycled in an informal setting is the &amp;#8220;Agbogbloshie dumpsite&amp;#8221; and the lack of appropriate recycling infrastructure has meant that rudimentary and inefficient methods; such as manual dismantling, burning, shredding, melting, and leaching, are applied with resultant significant adverse consequence on human and environmental health. The Agbogbloshie example of e-waste recycling as highlighted in this talk presents the global e-waste production not only as an emerging global health problem, but also as a developing global security issue. More research is therefore needed at the local level to better guide intervention strategies aimed at reducing environmental exposures associated with current recycling methods, while awaiting the development and deployment of acceptable, inexpensive, more efficient and environmentally cleaner technologies.

Uncovering energy saving and carbon reduction potential from recycling wastes: A case of Shanghai in China

With fast development and urbanization, Chinese cities are facing several challenges including issues of environmental pollution, climate change, resource depletion and landfills shortage. Waste recycling is one effective way to respond these challenges. Under such a situation, this paper aims to evaluate energy saving and carbon reduction potential of recycling wastes by taking Shanghai, the biggest city in China, as a case study. Results show that 8.7 Mt standard coal (tce) and 16.81 Mt CO2 could be reduced under current recycling system in Shanghai. And recycling of waste steel and nonferrous metals were the two dominant contributors, accounting for about 44% and 42% of energy saving, and 60% and 33% of CO2 reduction, respectively. If the recycling rates of main recyclable wastes were improved to 100%, additional 6.44 Mt energy and 10.02 Mt CO2 could be further saved, mainly from recycling waste glass, waste plastic and waste metals. Adoption of RPF (Refuse Plastic & paper Fuel) could further contribute to 1.24 Mt energy saving and 2.67 Mt CO2 reduction. Finally, policy implications on establishing a mature recycling system and promoting RPF technologies are discussed, in which the potential on reducing total energy consumption and CO2 emission of Shanghai can reach 6.6% and 4.9%, respectively.

Recycling of Rare Earth Element from Nickel Metal Hydride Battery Utilizing Supercritical Fluid Extraction

The anode of nickel metal hydride battery contains about 30 wt% of rare earth elements, namely, lanthanum, cerium, praseodymium, and neodymium. These elements are in increasing high demand, but facing supply uncertainty and near zero recycling. Current recycling practices rely on either pyrometallurgy or hydrometallurgy. The former is highly energy intensive and the latter relies on large volumes of acids and organic solvents, generating large volumes of hazardous residues. This study put the emphasis on developing an innovative and environmentally sustainable process for the urban mining of rare earth elements from nickel metal hydride battery. The developed process relies on supercritical fluid extraction utilizing CO2 as the solvent. This process is very efficient because it runs at low temperature, and does not produce hazardous waste, while recovering about 90% of rare earth elements.

Impact of Bio-Based Plastics on Current Recycling of Plastics

Bio-based plastics are increasingly appearing in a range of consumption products, and after use they often end up in technical recycling chains. Bio-based plastics are different from fossil-based ones and could disturb the current recycling of plastics and hence inhibit the closure of plastic cycles, which is undesirable given the current focus on a transition towards a circular economy. In this paper, this risk has been assessed via three elaborated case studies using data and information retrieved through an extended literature search. No overall risks were revealed for bio-based plastics as a group; rather, every bio-based plastic is to be considered as a potential separate source of contamination in current recycling practices. For PLA (polylactic acid), a severe incompatibility with PET (polyethylene terephthalate) recycling is known; hence, future risks are assessed by measuring amounts of PLA ending up in PET waste streams. For PHA (polyhydroxy alkanoate) there is no risk currently, but it will be crucial to monitor future application development. For PEF (polyethylene furanoate), a particular approach for contamination-related issues has been included in the upcoming market introduction. With respect to developing policy, it is important that any introduction of novel plastics is well guided from a system perspective and with a particular eye on incompatibilities with current and upcoming practices in the recycling of plastics.

Door-to-door recyclables collection programmes: Willingness to participate and influential factors with a case study in the city of Xanthi (Greece).

The implementation of a recyclable waste management system is a serious challenge for a society that aims to contribute to sustainability. The first operational step of such system is waste collection. In a number of European countries, the solid waste collection system has changed from the conventional kerbside system to a door-to-door collection. However, this type of waste collection system has not yet been introduced in Greece and its public acceptance prior to potential full implementation needs to be considered. This study aims to investigate the willingness of the residents of a Greek city (Xanthi, Thrace) to change from the existing kerbside collection system and initiate and participate in a door-to-door recyclable waste collection system instead. A questionnaire was designed and distributed randomly to 150 residents of Xanthi and a statistical analysis was then performed to assess the influence of a number of explanatory variables on recycling behaviour and the willingness to participate in a door-to-door collection system. The findings of this study indicate that most of the respondents (72.7%) were willing to participate in a future door-to-door recyclables collection programme in Xanthi. The factors that influenced the respondents' attitude with regard to such a programme were associated with level of education, their beliefs about the effectiveness of the current recycling system and also their attitudes towards recycling issues in general. Age and religion significantly affected recycling frequency. The survey and statistics presented in this article can be used as a model to assess the behaviour of citizens towards recyclable waste management systems worldwide.

Iron working in Anglo-Saxon England: New evidence to show fresh iron smelting of ironstone ores from the 6th–10th centuries CE

This paper discusses the current recycling and importation models of the Early Saxon iron economy. New evidence from the analysis of smelting slags and ores from the sites of Quarrington and Flixborough is presented which proves that fresh metal production was also occurring at this time, and with an increase in scale through the Saxon period. The findings are further supplemented by historical evidence which demonstrates that bedded iron ores were in use from at least the 7th century CE