Quantitative sustainability assessment of household food waste management in the Amsterdam Metropolitan Area

Life Cycle Sustainability Assessment of municipal solid waste management systems: a review

In the context of Circular Economy, the significance of municipal solid waste management systems (MSWMSs) has increased, as well as the need for comprehensive assessment tools of their sustainability. In the Life Cycle Thinking (LCT) framework, the Life Cycle Sustainability Assessment (LCSA), which is a methodology aiming to evaluate the environmental, economic, and social burdens throughout the various phases of waste management, has raised great interest. The paper describes the state-of-the-art of the implementation of LCT tools, with high regard to LCSA, for the evaluation of MSWMSs through their life cycle, with a deep focus on the use of both midpoint and endpoint categories. Drawing insights from an analysis of 69 case studies, the paper identifies the most frequently applied midpoint and endpoint categories for the sustainability assessment of MSWMSs. These categories are exposed in terms of their significance and applicability to specific waste management scenarios, providing valuable guidance for experts and researchers seeking to employ LCSA in MSWMSs assessments. Additionally, the paper outlines the limits associated with the implementation of LCSA, thereby highlighting areas for further research and improvement. In contrast to other reviews in this field, this paper uniquely focuses on the implementation of LCSA in the specific context provided by MSWMSs. By disseminating such insights, the paper aspires to foster the widespread adoption of LCSA by experts and researchers, ultimately advancing the sustainability discourse in municipal solid waste management.

Closing the nutrient cycle in urban areas: The use of municipal solid waste in peri-urban and urban agriculture

Cities face the challenges of supplying food and managing organic municipal solid waste (OMSW) sustainably amid increasing urbanization rates. Urban agriculture (UA) can help with this effort by producing local crops that are fertilized with nutrients recovered from compost generated from OMSW. This research aims to determine the potential of OMSW compost to supply the nitrogen-phosphorus-potassium (NPK) demand of UA and the environmental benefits of replacing mineral fertilizer from a life cycle perspective. The Metropolitan Area of Barcelona (AMB) serves as the case study given its commitment to reuse biowaste according to the Revised Waste Framework Directive and to promote UA as a signing member of the Milan Urban Food Policy Pact. Based on crop requirements and farmer surveys, we find that the annual NPK demands of the agricultural fields of the AMB that cover 5,500 ha and produce 70,000 tons of crops are approximately 769, 113, and 592 tons of NPK, respectively. Spatial material flow analysis and life cycle assessment were applied to found that the current waste management system can potentially substitute 8 % of the total NPK demanded by UA with compost, reduce the impacts by up to 39 % and yield savings in global warming of 130 %. The more ambitious future scenario of 2025 can potentially substitute 21 % of the total NPK demand and reduce environmental impacts up to 1,049 %, depending on the category considered. Avoiding processing of mixed OMSW, mineral fertilizer replacement and cogeneration of electricity from biogas are the major contributors to these environmental savings.

Wasted Food, Wasted Resources? A Critical Review of Environmental Impact Analysis of Food Loss and Waste Generation and Treatment

Food loss and waste (FLW) comes with significant environmental impacts and thus prevents a sustainable food system transition. Here we conducted a systematic review of 174 screened studies that assessed the environmental impacts of FLW generation and treatment. We found that the embodied impacts of FLW along the supply chain and impacts from FLW treatment received equal attention, but few studies have included both. The reviewed studies show narrow geographical (mostly conducted in industrialized countries) and food supply chain (mostly focused on the consumption stage) coverage. Life cycle analysis (LCA), material flow analysis (MFA), or their combination are the most commonly used to quantify FLW related environmental impacts. More method standardization, integration, and innovation and better FLW data with regional and stage resolution from a first-hand source are badly needed. Among the various proposed mitigation strategies covering technology, economy, behavior, and policy aspects, process optimization and waste management options are the most discussed. Our review calls for a more holistic environmental impact assessment of FLW generation and treatment and analysis of the trade-offs among different environmental impact categories and between supply chain stages, which would better inform relevant policy on effective environmental impact mitigation strategies toward sustainable food systems.

A model to assess the environmental and economic impacts of municipal waste management in Europe

The Monitoring Framework proposed in the EU27 New Circular Economy Action Plan comprises two mass-based indicators, namely overall recycling rate and recycling rate for specific waste streams. Yet, to monitor and assess the impacts of circular economy, indicators cannot be limited to mass-based indicators; we argue assessments should also include environmental and economic effects. Towards this end, these impacts can be quantified by an advanced model based on life cycle thinking, entailing the use of life cycle assessment and costing (LCA/LCC). Calculating these effects for municipal waste management is challenging due to gaps in available data for estimating generated waste. We propose a methodology to estimate more finely the amounts of waste generated in the Member States, complemented with LCA/LCC. The results highlight that important inconsistencies in municipal waste data reporting exist and that recycling rates calculated from these are lower than hitherto estimated. The impacts quantification shows great performance variation across EU27, with C-footprint ranging from -490 to 539 kg CO2-eq. t-1. Potentials for improvement are substantial and can bring up to 103 Mt CO2-eq. additional annual saving, reducing costs (calculated as Full Environmental LCC) of waste management by 8.4 billion EUR and bringing 206,100 new jobs in the sector. The approach presented highlights the rationale for improved data management on waste statistics and the potential for harmonised models. It also paves the way for more sophisticated impact analyses relevant for policymaking, by bringing a richer perspective to the environmental and economic impacts of waste management on top of tracking generated, collected and recycled waste flows.

Plastic impurities in biowaste treatment: environmental and economic life cycle assessment of a composting plant

The study focuses on an Italian composting plant and aims to investigate the impact of the presence of plastic impurities in the collected biowaste on the environmental and economic performance of the plant. The study is divided into two main steps: firstly, a material flow analysis was conducted to quantify the number of impurities (e.g., conventional plastics and compostable plastics) before and after the composting process. Secondly, a life cycle assessment (LCA) and a complementary life cycle costing (LCC) of the composting process were conducted. The results of the material flow analysis confirmed the initial assumption that conventional plastic remains almost constant before and after the composting treatment, while compostable plastic almost disappears. As far as the life cycle analyses are concerned, the most environmentally damaging phases of the process were the shredding and mixing phases, while the operating costs (OPEX) contributed the most to the total annual costs of the company. Finally, a further scenario analysis was performed, assuming that the plastic contaminants in the treated biowaste consisted exclusively of compostable plastics. The comparison with this ideal scenario can support decision-makers to understand the potential improvements achievable by addressing the presence of plastic impurities in the biowaste. The results show that the treatment of plastic impurities causes relevant environmental and economic impacts, being responsible for 46% of the total waste to treat at the end of the process, almost 7% of the total annual costs covered by the plant owners, and about 30% of all negative externalities.

Regionalized life-cycle monetization can support the transition to sustainable rural food waste management in China

Innovative recycling technologies can help curb food waste, yet their implementation often involves trade-offs among different environmental issues and among environmental, economic and social issues. Monetization can provide a solution to integrate all environmental impacts across the life cycle of food waste and to enable a normalized evaluation with economic accounting. Herein, a Chinese regionalized monetization model was applied to various indicators related to the environment, resource depletion and human health to assess ten typical rural food waste recycling technologies in Zhejiang province. The results reveal that biodrying and maturity and two bioconversion options are promising solutions, considering both environmental and economic impacts as well as the shifting of environmental impacts among different compartments as hidden risks. The monetization method proposed here could be applied to other sectors to support decision-making towards more sustainable development.

Environmental and economic impacts of improper materials in the recycling of separated collected food waste through anaerobic digestion and composting

Separately collected food waste (SC-FW) is effectively recycled through industrial anaerobic digestion (AD) and composting. However, the presence of improper materials in SC-FW not only generates technical problems to AD and composting, but also lowers the quality of the outputs of the processes. As a consequence, improper materials found in SC-FW cause not negligible environmental and economic burdens. In this study, the environmental and economic impacts due to the presence of unsuitable materials in the SC-FW, determined through compositional analysis, were estimated through life cycle assessment and environmental life cycle costing approaches. Three different scenarios were analysed for both AD and composting processes: (i) the current situation (CS); (ii) the improved scenario (AS) with an amount of improper materials in SC-FW reduced to 3 % (w/w); (iii) the ideal scenario (IS) with the total absence of foreign materials. Environmental benefits were determined for the AS and IS scenarios in 17 of the 19 analysed impact categories. Considering the GHG emissions, higher savings were measured for AD in AS and IS scenarios (47 % and 79 %, respectively) than in CS scenario. Similarly, savings of -10.4 kg fossil oil eq/ton_SC-FW (AS) and - 17.1 kg fossil oil eq/ton_SC-FW (IS) for AD could be obtained with respect to the CS scenario. Greater economic benefits were calculated for AD (-76.4 €/ton_SC-FW) and composting (-52.2 €/ton_SC-FW) in the IS scenario. Savings up to € 2,249,780 and € 3,888,760 could have been obtained in 2022 by reducing to 3 % (w/w) and eliminating, respectively, the amount of improper materials in the SC-FW. The results of the compositional analyses of SC-FW allowed to identify the incorrect behaviours in FW source-sorting activity and to plan interventions to improve the current FW management system. The quantified environmental and economic benefits could further motivate citizens to correctly differentiate FW.

Transitioning towards a sustainable circular city: How to evaluate and improve urban solid waste management in Brazil

A circular city (CC) promotes circular economy (CE) principles. Efficient urban solid waste management (USWM) strategies are essential for promoting a CE at the municipal level. New tools are needed to evaluate waste management (WM) and increase the reuse and recycling of materials to accelerate the transition towards a CC. These tools could assist decision and policymakers in adopting, implementing, and monitoring circular practices. This study proposes creating an index (USWM-index) to evaluate WM in urban areas and discuss how it could be better managed in future sustainable circular cities in Brazil. The index allows city managers to integratively and sustainably assess their USWM. Decision-makers can also use the index to set goals and objectives for recycling and reusing generated waste in cities. The index comprises 19 indicators and 51 sub-indicators. These elements were divided into five groups: Operational, Environmental, Political-economic, Educational, and Social. Cities can assess their performance in each group by using the USWM-index. The index was applied to four Brazilian cities. All cities had their USWM classified as average, and they did not have initiatives to transition to sustainable circular cities regarding WM. This study presents guidelines for transitioning from a linear city to a sustainable circular city in terms of WM.

Testing the stakeholders' partnership in a tourism waste management network: an ERGM approach

The exponential random graph model (ERGM) is an effective approach for testing the dynamic and local processes of a network. This paper explores the structure of stakeholders' partnerships in a tourism waste management network using high-order dependency ERGMs based on relational data obtained from a field survey in Motuo County, China. The results reveal that (1) the network has many edges, indicating a tight network; (2) the geometrically weighted edge distribution shows a high transitive effect of the network; (3) the structural effect is more significant than the attribute effect; (4) there is a good agreement between the simulation results and observations, suggesting a tourism waste network with close connections and collaborative division of labor. These findings indicate that different groups of stakeholders have been extensively involved in tourism waste management in Motuo County. The edgewise shared partners formed by stakeholders of different groups increase the information transmission efficiency of the network. The results have implications for tourism waste management, specifically for promoting sustainability transitions via network governance.

A systemic review for measuring circular economy with multi-criteria methods

Determining the circularity of a system through a criteria and indicators approach has been the focus of research in many branches of science. In this way, this work aims to review multiple criteria decision-making (MCDM) methods employed for measuring circular economy (CE) indicators and CE aspects at different levels (micro, meso, and macro). For this purpose, a systematic literature review (SLR) was conducted in ISI Web of Science and Scopus databases. Further, the results summarized 22 MCDM techniques, 27 CE aspects, and 36 CE indicators The SLR provides a concept map highlighting the relation of the level of circularity implementation (subdivided into micro-, meso-, and macro-levels) and MCDM techniques and demonstrates the interaction between CE aspects and indicators. The review provides an outline as to how MCDM techniques can solve problems related to CE aspects and marks the relevance in the use of CE indicators to support circularity aspects and to construct criteria in the methodologies applied.

Decentralized Processing Performance of Fruit and Vegetable Waste Discarded from Retail, Using an Automated Thermophilic Composting Technology

Food waste generation is increasing at an exponential rate, affecting the environment, food security, and causing major economic issues worldwide. The main aim of the current research is to investigate a novel composting technology that is still in its early stages of development. The proposed composting technology combining thermophilic composting with the use of advanced automated processing reactors. Starting from a qualitative and quantitative analysis of the waste generated at retail-stores, the most significant difficulties associated to waste management as well as the main characteristics of the discarded waste were identified. The findings allowed to design and evaluate the real operating performance of an automated thermophilic composting prototype (working in a decentralized regime), with the goal of delivering a faster processing system, improving operational efficiency, reducing expenses, and lowering environmental impacts. The proposed operating technique showed a high capacity for pathogens and seeds removal, the waste input mass reduction of 88%, and efficiency in food processing (2235 kg of fruits and vegetables in a 14-days timeframe).

Sustainability assessment of organic waste management in three EU Cities: Analysing stakeholder-based solutions

This study focuses on a comprehensive sustainability assessment of the management of the organic fraction of municipal solid waste in Ghent (Belgium), Hamburg (Germany) and Pécs (Hungary). A sustainability assessment framework has been applied to analyse social, environmental, and economic consequences at the midpoint level (25 impact categories) and at the endpoint level (5 areas-of-protection). For each case study, the reference scenario was analysed, along with three solutions to improve the sustainability performance, which were selected and developed with the collaboration of local stakeholders. The solutions focus on food waste prevention, collection (increasing separate collection and household composting) and/or valorisation treatment (insect breeding, bioplastic production and improvement of centralised treatment). The results show that food waste prevention results in substantial improvements in all areas of protection when a significant quantity of food is saved. Solutions proposing innovative treatments such as insect breeding do not show clear improvements at the endpoint level, given current technology development level, but appear promising for some categories such as Revenues, Ecotoxicity, Land Use or Particulate Matter if the substituted products compensate the impact of the treatment (e.g., energy and water use). Enhancing the separate collection of organic waste can improve sustainability, but trade-offs may arise, e.g., decreased environmental savings from energy recovery at incineration. For this, the influence of the electricity mix (more or less decarbonised) should be carefully considered in future studies. The application of the solutions proposed to other cities should also consider potential bottlenecks such as legislation barriers, public acceptance, or management costs.