Future Waste Research Articles

End-of-life treatment of EPS-based building insulation material – An estimation of future waste and review of treatment options

Expanded Polystyrene (EPS) used in External Thermal Insulation Composite Systems (ETICS) is mainly disposed of in waste incineration plants. However, alternative recycling options need to be identified as capacities for this waste treatment are limited and the amount of EPS-based ETICS waste is expected to increase. Herein, it is necessary to quantify the future waste masses with regard to regional distribution as EPS-based ETICS waste is generated decentrally. Furthermore, consistent information on alternative treatment options for EPS-based ETICS waste is lacking.First, we estimate the amount of upcoming EPS waste from ETICS in Germany with a high spatial resolution. Second, we evaluate state-of-the-art waste management options regarding economic, legal and environmental aspects. We find that waste masses will increase from 3 to 33 kt (2020-2040) with large spatial deviations. We conclude that solvent-based recycling seems promising, but more sophisticated analyses are required, i.e. planning of the future waste treatment infrastructures.

Newton trust-region methods with primary variable switching for simulating high temperature multiphase porous media flow

Coupling multiphase flow with energy transport due to high temperature heat sources introduces significant new challenges since boiling and condensation processes can lead to dry-out conditions with subsequent re-wetting. The transition between two-phase and single-phase behavior can require changes to the primary dependent variables adding discontinuities as well as extending constitutive nonlinear relations to extreme physical conditions. Practical simulations of large-scale engineered domains lead to Jacobian systems with a very large number of unknowns that must be solved efficiently using iterative methods in parallel on high-performance computers. Performance assessment of potential nuclear repositories, carbon sequestration sites and geothermal reservoirs can require numerous Monte-Carlo simulations to explore uncertainty in material properties, boundary conditions, and failure scenarios. Due to the numerical challenges, standard NR iteration may not converge over the range of required simulations and require more sophisticated optimization method like trust-region.We use the open-source simulator PFLOTRAN for the important practical problem of the safety assessment of future nuclear waste repositories in the U.S. DOE geologic disposal safety assessment Framework. The simulator applies the PETSc parallel framework and a backward Euler, finite volume discretization. We demonstrate failure of the conventional NR method and the success of trust-region modifications to Newton’s method for a series of test problems of increasing complexity. Trust-region methods essentially modify the Newton step size and direction under some circumstances where the standard NR iteration can cause the solution to diverge or oscillate. We show how the Newton Trust-Region method can be adapted for Primary Variable Switching (PVS) when the multiphase state changes due to boiling or condensation. The simulations with high-temperature heat sources which led to extreme nonlinear processes with many state changes in the domain did not converge with NR, but they do complete successfully with the trust-region methods modified for PVS. This implementation effectively decreased weeks of simulation time needing manual adjustments to complete a simulation down to a day. Furthermore, we show the strong scalability of the methods on a single node and multiple nodes in an HPC cluster.

Waste management in Iceland: Challenges and costs related to achieving the EU municipal solid waste targets

Waste management in Iceland has developed considerably in recent years. Before 1990, most of the waste was either burnt in open pits or landfilled. In the past, information about waste management in Iceland used to be almost exclusively published in reports and was primarily based on rough estimates. Currently, incinerators and landfilling sites are highly regulated and follow EU legislation. Additionally, reporting has gradually improved and is approaching EU standards, although improvement is still needed. In an international context, Iceland is far behind the other Nordic countries as well as the EU-27 countries in reducing landfill rates and enhancing energy recovery and recycling rates. According to the EU landfill directive, the total amount of municipal solid waste (MSW) landfilled must be below 10% by 2035; however, it is currently over 60%. Other targets are similarly far off, and it is unlikely that Iceland will meet those in time without immediate and significant changes in waste management. This article aims to evaluate MSW management in Iceland at the national and regional levels, its compliance with the EU’s targets for waste management and the associated costs inflicted on municipalities. Hence, annual accounts data were used when comparing regions and municipalities. It was found that there are significant differences in per capita waste management expenditure between municipalities with less than 1,000 inhabitants (€379) and ones with more than 10,000 inhabitants (€106). Without changes in proposed future waste management strategies, this gap will inevitably increase in the upcoming years.

A review of computational modeling techniques for wet waste valorization: Research trends and future perspectives

The conversion of wet waste (e.g., food waste, sewage sludge, and animal manure) into bioenergy is a promising strategy for sustainable energy generation and waste management. Although experimental efforts have driven waste conversion technologies (WCTs) to various degrees of maturity, computational modeling has equally contributed to this endeavor. This review focuses on the application of modeling techniques, including computational fluid dynamics (CFD), process simulation (PS), and machine learning (ML) on WCTs including anaerobic digestion, hydrothermal carbonization, gasification, pyrolysis and incineration. It addresses in a concise manner on how CFD models aid in understanding of the complex process and their molecular kinetics; while PS and ML models help in understanding the reaction kinetics, variable-response relationship, techno-economic assessment and sensitivity analysis. Relevant modeling approaches with their pros and cons are summarized and case studies are presented for each WCT. Moreover, a comparative evaluation among the three modeling techniques, along with their recent and ongoing developments are highlighted. Hybrid frameworks derived by combining mechanistic and ML models are proposed, which are expected to advance future wet waste valorization strategies for sustainable clean energy production and waste management.

Life-cycle assessment for municipal waste management systems

One of the important tasks of the environmental policy of the Russian Federation is to implement an integrated regional waste management system through the active involvement of production and consumption waste in the economic turnover, the use of environmentally sound recycling methods, the solution of environmental problems related to waste management and resource conservation. Environmental assessment of the existing municipal waste management system is carried out by analyzing the environmental impact and alternative waste management scenarios in order to develop an integrated waste management system for Irkutsk region. Modelling of production and consumption waste flows and their potential impact on the environment was performed. The method of material flow analysis using STAN software was used to estimate the fractional composition of waste. The method of life cycle assessment (LCA) was used to determine the environmental indicators, using the EASETECH software package, which allows for creating various scenarios of environmental impacts, comparing them and choosing the most optimal and environmentally safe one. The modelling of alternative future waste management scenarios for Irkutsk Region showed that all alternatives can improve the current waste management system, which primarily involves landfilling in an uncontrolled landfill without environmental measures. Construction of a new landfill with gas disposal and leachate treatment is a significant improvement, and recycling of secondary raw materials can reduce the environmental pressure. From an environmental point of view, the current waste disposal system is not efficient. Uncontrolled landfill is the main impact on global warming. Although a new landfill could significantly reduce this impact, it is worth reconsidering the waste management systems paying more attention to recycling rather than to landfilling.

Environmental geophysical study for ideal locations of landfill within Iraqi Southern Desert

Solid wastes and toxic chemicals are the main contributors, which influence the environment and quality of life. Demographic population, economic and building structures considered as major factors that are controlling such pollution. Therefore, it is very important to find proper areas to dispose of these pollutants. The current study aims to find best locations for wastes disposal areas that comply with the national and international standards. The study area, the Iraqi Southern Desert had been subjected to comprehensive study for geology, gravity and magnetic investigations. The existence of impermeable beds, tectonic, seismology and structural features show that the area understudy is located in the stable shelf that has no folding and faulting complexity; however, the saline groundwater lies at about 150 m depth. The gravity field data were analyzed using three methods: Trend Surface Analysis, Average Smooth Matrix and the First Vertical Derivative. Negative and positive gravity anomalies were noticed and interpreted. Remote sensing is also carried out in order to locate linear features, drainage patterns and watersheds within the Southern Desert depending on the interpretation of satellite images of the study area. Finally, a comparison of natural and environmental factors with remote sensing and both gravity and magnetic analyses gives thirteen locations of different coordinates. Only sites 1, 2, 3,10 and 13 yield good environment satisfaction agreement that permits us to choose them as a good locations for future landfill waste purposes.

Hong Kong Citizens’ Socio-Demographic Dynamics of Urban Yard Waste Facilities Siting and Legislation Preferences

The public opinions on yard waste (YW) facility siting and legislation reflect public needs and anticipations on the ways they perceive and deal with such urban yard waste, which aid to ascertain why and how people participate in YW treatment activities and support future urban yard waste policy development. However, such relevant and specific social survey on above issues remains limited, thereby scant attention has been given to the related socio-demographic explorations. This study focuses on the YW facility siting and legislation public opinions, and relevant associations across socio-demographic groups in Hong Kong, China. Data were obtained from 202 mostly cultured respondents randomly gleaned by online questionnaire survey. More than half of respondents did not reject to having the YW treatment facilities in their neighborhood. The statistical association between the opposing opinion toward having YW treatment facility near home and education level was rather strong. The majority of the tertiary-educated group expressed the strongest counter-opposition view towards YW facility within the community, while those with secondary education background had no comment. Nearly 62% of respondents supported the outlawing of direct dumping of YW to landfill, and the majority of them were cultured citizens. Decision makers should prudently consider the expressed needs and hopes of the socio-demographically differentiated subpopulations, and factor in their public opinions into the decision-making process for progressing local urban yard waste governance and overall environmental sustainability.

A Review of Future Household Waste Management for Sustainable Environment in Malaysian Cities

In recent years, Malaysia has faced environmental challenges caused by municipal solid waste, especially household waste, during the COVID-19 pandemic. Among all the household waste, plastic and paper are the most unmanaged waste that cause environmental issues. Several recycling associations in Malaysia have carried out their practices for better waste sustainability and management to curb the increasing amount of household waste. However, the effectiveness is still vague in achieving smart and effective household waste management. Therefore, this paper aims to investigate Malaysia’s household waste management, mainly in three significant municipalities in Malaysia, namely Kuala Lumpur, Penang, and Melaka, in becoming a resilient and sustainable city by addressing two main research questions: (1) What are the key factors for ensuring the more successful moves for future household waste management in cities? and (2) How do each of the three municipalities of Malaysia cities address their waste issues based on the key factors from RQ1? This paper reviewed 13 waste management articles and explores the potential of the four factors of waste management from the perspective of technology and data, economy, social, and governance. The discussed factors and models contributed to an integrated future-proofing framework that focuses on smart waste tracking, a gamified awareness education, and strict policies to control waste management are the way forward for the future of smart cities household waste management.

Optimal location and operation of waste-to-energy plants when future waste composition is uncertain

In many countries, waste management is increasingly geared towards a circular economy, aiming for a sustainable society with less waste generation, fewer landfills, and a higher rate of recycling. Waste-to-Energy (WtE) plants, which convert waste into heat and energy, can contribute to the circular economy by utilizing types of waste that cannot be recycled. Due to the varying quality of sorting and socio-economic conditions in individual regions, the waste composition differs between regions and has an uncertain future development. Waste composition significantly affects the operation of WtE plants due to differences in energy potential. This paper supports strategic capacity planning for waste energy recovery by introducing a two-stage stochastic mixed-integer linear programming model that captures waste composition uncertainty through scenarios of possible future development. The results of the model provide insights into the economics of operation and identify important factors in the sustainability of the waste handling system. The model is demonstrated on an instance with six scenarios for waste management in the Czech Republic for the year 2030. The solution of the proposed model is to build 14 new WtE plants with a total capacity of 1970 kt in addition to the four existing plants with a capacity of 831 kt. The annual energy recovery capacity is expected to increase almost four times to satisfy EU directives that restrict waste landfilling.

Detailed spatial analysis of renewables’ potential and heat: A study of Groningen Province in the northern Netherlands

Spatially sensitive regional renewables’ potentials are greatly influenced by existing land-use claims and related spatial and environmental policies. Similarly, heat particularly related to low-temperature demand applications in the built environment (BE) is highly spatially explicit. This study developed an analytical approach for a detailed spatial analysis of future solar PV, onshore wind, biomass, and geothermal and industrial waste heat potentials at a regional level and applied in the Dutch Province of Groningen. We included spatial policies, various spatial claims, and other land-use constraints in developing renewable scenarios for 2030 and 2050. We simultaneously considered major spatial claims and multiple renewable energy sources. Claims considered are the BE, agriculture, forest, nature, and network and energy infrastructure, with each connected to social, ecological, environmental, technical, economic, and policy-related constraints. Heat demand was further analyzed by creating highly granular demand density maps, comparing them with regional heat supply potential, and identifying the economic feasibility of heat networks. We analyzed the possibilities of combining multiple renewables on the same land. The 2050 renewable scenarios results ranged 2–66 PJ for solar PV and 0–48 PJ for onshore wind and biomass ranged 3.5–25 PJ for both 2030 and 2050. These large ranges of potentials show the significant impact of spatial constraints and underline the need for understanding how they shape future energy policies. The heat demand density map shows that future heat networks are feasible in large population centers. Our approach is pragmatic and replicable in other regions, subject to data availability.

Effects of implantation temperature and annealing on structural evolution and migration of Se into glassy carbon

The use of glassy carbon (GC) as a future nuclear waste storage material depends on its capability to retain all radioactive fission products found in spent nuclear fuels. Selenium (79Se) is found in trace amounts in uranium ores, spent, and reprocessed nuclear fuel. This work investigates the effects of implantation temperature and annealing on the structural evolution and migration of Se implanted GC. To achieve these objectives, 150 keV Se+ was implanted into GC samples separately at room temperature (RT) and 200 °C to a fluence of 1 × 1016 cm−2. Some of the as-implanted samples were annealed at 1000, 1100 and 1200 °C for 5h and characterised by transmission electron microscopy (TEM), Raman spectroscopy, and secondary ion mass spectrometry (SIMS). Both TEM and Raman spectroscopy showed that implantation caused defects in the GC structures, with more defects in the RT as-implanted sample. Annealing caused the healing of both sample types but retained some radiation damage. No migration of Se atoms was observed in the RT and 200 °C as-implanted samples. However, a different migration behaviour was seen after annealing the RT and 200 °C samples up to 1200 °C, attributed to the trapping and de-trapping of Se atoms in different amounts of defect induced by implantation.

Carbon Fiber Reinforced Plastics in Space: Life Cycle Assessment towards Improved Sustainability of Space Vehicles

Composite materials, specifically carbon fiber reinforced plastics (CFRPs), are used in various applications such as the automotive, aerospace, and renewable energy industries, thus increasing their global production and volume consumption and creating a subsequent increase in CFRP waste. Especially in space applications and Vega launcher construction, the use of CFRP components to replace metal envisages significant benefits in the use phase by reducing weight and fuel consumption requirements. The current and future waste management and environmental legislation, considering the actual and impending EU framework on waste management, requires all engineering materials to be properly recovered and recycled from EoL products. In this study, the potential of recycling and the subsequent environmental benefits have been assessed by investigating the EoL of CFRPs through a life cycle assessment (LCA). LCA is a valuable tool for evaluating a composite material’s environmental ecological burdens over its lifetime. Therefore, it is important to the composites industry as a material selection tool when determining the applicability of recycled composites in the design phase. Particularly, the benefits from recycling methods were systematically studied in order to assess the environmental impacts of EoL scenarios, to underline the importance and necessity for the maturity increase in recycling technologies for CFRPs.

Quantification and composition of pharmaceutical waste in New Zealand

This study aimed to quantify the amount of pharmaceutical waste produced in New Zealand, and determine the composition of pharmaceutical waste from community pharmacies in Auckland, New Zealand. Pharmaceutical waste collected in New Zealand is increasing, peaking at 542 tonne in 2019. Pharmaceutical waste collected from hospitals and pharmacies in Auckland increased by more than fourfold from 2016 to 2020. An audit of the types of pharmaceutical waste collected from community pharmacies revealed that the most common classes of drugs identified in this waste stream belonged to the nervous system, cardiovascular system and alimentary tract, and metabolism. Following examination of the contents of 12 pharmaceutical waste bins, 475 different pharmaceutical products were identified, highlighting the breadth of drugs in this waste stream. A range of dosage forms and hence materials were identified, which could present challenges for future waste treatment approaches. Hazardous drugs were identified including cytotoxic compounds, which should go into a separate waste stream for incineration. There is a need for similar data to be collected from multiple sites to fully appreciate the magnitude and composition of pharmaceutical waste. This will allow for the suitability of current practices for managing this hazardous waste stream to be evaluated.

An Ensemble Learning Based Classification Approach for the Prediction of Household Solid Waste Generation.

With the increase in urbanization and smart cities initiatives, the management of waste generation has become a fundamental task. Recent studies have started applying machine learning techniques to prognosticate solid waste generation to assist authorities in the efficient planning of waste management processes, including collection, sorting, disposal, and recycling. However, identifying the best machine learning model to predict solid waste generation is a challenging endeavor, especially in view of the limited datasets and lack of important predictive features. In this research, we developed an ensemble learning technique that combines the advantages of (1) a hyperparameter optimization and (2) a meta regressor model to accurately predict the weekly waste generation of households within urban cities. The hyperparameter optimization of the models is achieved using the Optuna algorithm, while the outputs of the optimized single machine learning models are used to train the meta linear regressor. The ensemble model consists of an optimized mixture of machine learning models with different learning strategies. The proposed ensemble method achieved an R2 score of 0.8 and a mean percentage error of 0.26, outperforming the existing state-of-the-art approaches, including SARIMA, NARX, LightGBM, KNN, SVR, ETS, RF, XGBoosting, and ANN, in predicting future waste generation. Not only did our model outperform the optimized single machine learning models, but it also surpassed the average ensemble results of the machine learning models. Our findings suggest that using the proposed ensemble learning technique, even in the case of a feature-limited dataset, can significantly boost the model performance in predicting future household waste generation compared to individual learners. Moreover, the practical implications for the research community and respective city authorities are discussed.

Identifying Suitable Solid Waste Landfill Sites Using Spatial Multi-Criteria Decision Analysis

The required skill sets for dealing with solid waste management are lacking in developing countries. Further, this issue is compounded by the rapid growth of waste generation in those countries. This study helps to address this problem by performing a landfill site selection for the Twin Cities of Pakistan. The study uses a multi-criteria decision model for siting a suitable landfill utilizing Geographic Information Systems (GIS). The use of geospatial technology provides network-based spatial analysis and assists in modeling practical network situations. In particular, this analysis accounts for proximity to urban/residential areas, road networks, water streams, and water reservoirs/lakes. It also accounts for land slope and land use/land cover. The results indicate that 96.3% of the Twin Cities area is unsuitable, 1.6% is moderately suitable, and 2.1% is most suitable. The results of the study identify appropriate sites for more detailed analysis based on current and future land use, population growth, and waste generation. As similar challenges of handling solid waste are common in developing countries, this study can serve as a guide in other developing countries.

Perspectives on food waste management: Prevention and social innovations

Food waste is one of the challenging issues humans are facing. A third of the food produced in the world is wasted at various points along the food supply chain. Food waste can be reduced by developing technology that can be utilized in different parts of the food value chain and through education programs that focus on consumers' behavior on healthy lifestyles and sustainable consumption. This article examines the problem of food waste and provides insights into the approaches to food waste management. Different techniques, such as education-based or structure-based, are used to encourage food waste prevention and management. Therefore, highlighting the current development in food waste management becomes important. The paper uses a systematic review that supports screening of the literature to answer the research questions and find the research gaps. According to the findings, food is either thrown out during the supply chain or even at the last stages of preparation and consumption. The review shows that the current food waste management treatment methods may be effective, but they do not provide an environmentally sustainable solution for food waste management. Therefore, the proposed article deeply investigated food waste prevention and social innovations to reduce food waste. This review complements the previous reviews by adding social and economic innovation focus on food waste management. The article recommends a course of action for future food waste management research.

Polylactic acid-graphene emulsion ink based conductive cotton fabrics

Manufacturing bio-based and biodegradable materials for electronic applications is a swiftly growing field today. This approach can effectively tackle the future electronic waste problems. However, the preparation of such sustainable materials with high conductivity remains a challenging task. Moreover, in many cases, the use of noxious solvents may be unavoidable. This study shows the feasibility of an aqueous emulsion-based printable conductive ink to be used in the field of flexible electronic devices. The emulsion ink contains polylactic acid (PLA) as a binder and graphene nanoplatelets as a conductive filler. It shows an encouraging electrical conductivity of 34.5 S/m when spray-coated onto a cotton fabric. Moreover, the conductive composite fabrics were very stable in cyclic strain tests, suitable for wearable electronics. A hot pressing post-treatment of the printed composite fabrics improved the electrical conductivity by up to two times. Additionally, the coatings also enhanced the mechanical properties of the cotton fabrics by increasing the Young's modulus values almost twice compared to pristine fabric. This eco-friendly composite ink can be used as strain sensors for transforming certain electronic components into biodegradable versions.

Energy decarbonisation in the European Union: Assessment of photovoltaic waste recycling potential

The Renewable Energy Directive delineates policies for energy production from renewable sources by at least 32% in European Union (EU) by 2030. All member states have established National Energy and Climate Plans (NECPs) for 2021–2030 to decipher how they will cover their energy needs from renewable sources. This work considers the targets set by each of the EU-27 countries to implement, in particular, solar photovoltaic (PV) modules to cover their energy needs. Then, the future PV waste amounts are assessed considering the widely used Early Loss and Regular Loss scenarios, as well as the noteworthy scenario proposed by the EU WEEE Directive. The study addresses the questions “when will large amounts of panel waste be generated in the EU countries and what will their composition be?” Also, a timescale for starting an economically viable recycling industry for PV panel waste in the EU is estimated based on the annual PV waste generated in each country. By 2050, 14.3–18.5 Mt PV waste will be generated in EU-27 while the profit of PV recovered materials will be 21.98–27.36 billion USD. The findings contribute to the efficient management of the forthcoming e-waste category, according to circular economy principles, ensuring the pathway to sustainability.

Tourist’s Willingness to Pay toward Waste Management in Mount Salak Endah Tourism Area, Bogor District

Mount Salak Endah (GSE) Natural Tourism Area is one of the tourism destinations in the conservation area of Mount Halimun Salak National Park, which is located in Bogor District. GSE is easy to reached, whether from Bogor or Jakarta. GSE has various beautiful natural destinations such as Cigamea Waterfalls, Kondang Waterfalls and hot spring attracting many visitors. The numbers of visitors keep increasing every year, but it is impacted to environmental problem, i.e. and in the end, it causes environmental problem: waste generation. The objectives of this study are (1) to identify and explore tourist perceptions regarding current and future waste management in the GSE natural tourism area and (2) Calculating the tourist’s willingness to pay related to the implementation of tourist-based waste management in GSE natural tourism area. This study used a Likert scale data collection method and Contingent Valuation Method (CVM). The tourist’s perception regarding waste management in the GSE natural tourism area shows positive result where tourists are willing to manage their waste with deposit refund.

Assessing China’s potential for reducing primary copper demand and associated environmental impacts in the context of energy transition and “Zero waste” policies

To conserve resources and enhance the environmental performance, China has launched the “Zero waste” concept, focused on reutilization of solid waste and recovery of materials, including copper. Although several studies have assessed the copper demand and recycling, there is a lack of understanding on how different waste management options would potentially reduce primary copper demand and associated environmental impacts in China in the context of energy transition. This study addresses this gap in view of a transition to low-carbon energy system and the optimization of copper waste management combining MFA and LCA approaches. Six types of waste streams (C&DW, ELV, WEEE, IEW, MSW, ICW) are investigated in relation to various “Zero waste” strategies including reduction, reuse (repair, remanufacturing or refurbishment), recycling and transition from informal to formal waste management. Under present Chinese policies, reuse and recycling of copper containing products will lead to a somewhat lower dependency on primary copper in 2100 (11187Gg), as well as lower total GHG emissions (64869 Gg CO2-eq.) and cumulative energy demand (1.18x10^12 MJ). Maximizing such “Zero waste” options may lead to a further reduction, resulting in 65% potential reduction of primary copper demand, around 55% potential reduction of total GHG emissions and total cumulative energy demand in 2100. Several policy actions are proposed to provide insights into future waste management in China as well as some of the challenges involved.