Life Cycle Assessment of Industrial Symbiosis for Circular Solid Waste Management: A Literature Review

Solid waste increase is inevitable globally due to anthropogenic activities. This adds burden to waste management systems in developing countries including Zimbabwe. Currently, life cycle assessment (LCA) model is used to achieve sustainability and circular economy (CE) in solid waste management. Therefore, the main goal of this paper was to unearth LCA model applicability in solid waste management in Zimbabwe. Data sources were retrieved from databases like Scopus, ScienceDirect and Springer, although government documents were also used. In Zimbabwe, organic and inorganic solid waste is generated from various sources, namely industries, institutions and households. Solid waste management in Zimbabwe is based on traditional linear approach where waste is collected and disposed through landfilling, burning, incineration, burying, open pits or illegally. Most disposal approaches occupy base of waste management pyramid, hence posing detrimental impacts to human health, terrestrial, aquatic and atmospheric ecosystems. Management approaches are far from Agenda 21, Sustainable Development Goals (SDGs), Zimbabwe Vision 2030 and National Development Strategy 1 demands. Literature revealed that LCA model can be utilised to achieve sustainable solid waste management in countries like Zimbabwe. LCA model is essential in management of solid waste in Zimbabwe, since it assists decision makers in selecting management approaches with less environmental health impacts. Moreover, LCA enables application of waste material reuse, recycle, repairing and recovery, thus narrowing the gap to achieve CE and economic growth in Zimbabwe. Owing to LCA model implementation of waste management legislation and policies which support energy recovery and circular economy became easier in Zimbabwe.

Life cycle assessments of municipal solid waste management systems: A comparative analysis of selected peer-reviewed literature

Application of life cycle assessment in municipal solid waste management: A worldwide critical review

The body of life cycle assessment (LCA) literature is vast and has grown over the last decade at a dauntingly rapid rate. Many LCAs have been published on the same or very similar technologies or products, in some cases leading to hundreds of publications. One result is the impression among decision makers that LCAs are inconclusive, owing to perceived and real variability in published estimates of life cycle impacts. Despite the extensive available literature and policy need formore conclusive assessments, only modest attempts have been made to synthesize previous research. A significant challenge to doing so are differences in characteristics of the considered technologies and inconsistencies in methodological choices (e.g., system boundaries, coproduct allocation, and impact assessment methods) among the studies that hamper easy comparisons and related decision support. An emerging trend is meta-analysis of a set of results from LCAs, which has the potential to clarify the impacts of a particular technology, process, product, or material and produce more robust and policy-relevant results. Meta-analysis in this context is defined here as an analysis of a set of published LCA results to estimate a single or multiple impacts for a single technology or a technology category, either in a statisticalmore » sense (e.g., following the practice in the biomedical sciences) or by quantitative adjustment of the underlying studies to make them more methodologically consistent. One example of the latter approach was published in Science by Farrell and colleagues (2006) clarifying the net energy and greenhouse gas (GHG) emissions of ethanol, in which adjustments included the addition of coproduct credit, the addition and subtraction of processes within the system boundary, and a reconciliation of differences in the definition of net energy metrics. Such adjustments therefore provide an even playing field on which all studies can be considered and at the same time specify the conditions of the playing field itself. Understanding the conditions under which a meta-analysis was conducted is important for proper interpretation of both the magnitude and variability in results. This special supplemental issue of the Journal of Industrial Ecology includes 12 high-quality metaanalyses and critical reviews of LCAs that advance understanding of the life cycle environmental impacts of different technologies, processes, products, and materials. Also published are three contributions on methodology and related discussions of the role of meta-analysis in LCA. The goal of this special supplemental issue is to contribute to the state of the science in LCA beyond the core practice of producing independent studies on specific products or technologies by highlighting the ability of meta-analysis of LCAs to advance understanding in areas of extensive existing literature. The inspiration for the issue came from a series of meta-analyses of life cycle GHG emissions from electricity generation technologies based on research from the LCA Harmonization Project of the National Renewable Energy Laboratory (NREL), a laboratory of the U.S. Department of Energy, which also provided financial support for this special supplemental issue. (See the editorial from this special supplemental issue [Lifset 2012], which introduces this supplemental issue and discusses the origins, funding, peer review, and other aspects.) The first article on reporting considerations for meta-analyses/critical reviews for LCA is from Heath and Mann (2012), who describe the methods used and experience gained in NREL's LCA Harmonization Project, which produced six of the studies in this special supplemental issue. Their harmonization approach adapts key features of systematic review to identify and screen published LCAs followed by a meta-analytical procedure to adjust published estimates to ones based on a consistent set of methods and assumptions to allow interstudy comparisons and conclusions to be made. In a second study on methods, Zumsteg and colleagues (2012) propose a checklist for a standardized technique to assist in conducting and reporting systematic reviews of LCAs, including meta-analysis, that is based on a framework used in evidence-based medicine. Widespread use of such a checklist would facilitate planning successful reviews, improve the ability to identify systematic reviews in literature searches, ease the ability to update content in future reviews, and allow more transparency of methods to ease peer review and more appropriately generalize findings. Finally, Zamagni and colleagues (2012) propose an approach, inspired by a meta-analysis, for categorizing main methodological topics, reconciling diverging methodological developments, and identifying future research directions in LCA. Their procedure involves the carrying out of a literature review on articles selected according to predefined criteria.« less

Circular utilization of urban tree waste contributes to the mitigation of climate change and eutrophication

Investigating the use of network analysis metrics to benchmark Industrial Symbiosis development

This paper highlights the methods and parameters used to define and design a reference scenario to be compared with an industrial symbiosis (IS) scenario using the life cycle assessment (LCA) methodology. To this end, a critical review was conducted of 26 peer‐reviewed papers using LCA in the field of IS. The analysis focuses on the definition and design of reference scenarios through five cross‐analyses to determine correlations between the type and the number of reference scenarios and the type of IS scenarios studied and also some LCA characteristics such as the functional unit, the type of data used, and the use of sensitivity analysis. Results show that the definition of reference scenarios depends mainly on the type of IS scenario considered. For a current IS developed at an industrial scale, the suitable reference scenario is mainly a hypothetical nonsymbiotic reference scenario. For a prospective IS, the suitable reference scenario is mainly a current nonsymbiotic reference scenario. Due to this critical review, the problem of variability of reference scenarios emerges. To resolve it, the authors analyze different reference scenarios or use sensitivity analysis. What is more, territorial aspects are rarely taken into account in the design of reference scenarios. It is clearly a gap for LCA of IS because of the influence of territorial factors. The new research challenge is to include the consideration of territorial aspects to define and design the worst‐ and best‐case reference scenarios to assess strict environmental performances of IS.

Evaluation of promoting industrial symbiosis in a chemical industrial park: A case of Midong

Integrated Municipal Solid Waste (MSW) management is a tedious task requiring the simultaneous fulfilment of technical, economical and social constraints. It combines a range of collection and treatment methods to handle all materials in the waste stream in an environmentally effective, economically affordable and socially acceptable way (McDougall, 2001). Due to the complexity of the issues required for effective integrated MSW management, various computer-aided approaches that help the decision makers reach their final decision have been engaged since the early days of integrated MSW management. Any computer-based system supporting decision making is defined as a DSS (Finlay, 1989). DSS incorporate computer-based models of real life biophysical and economic systems. There are two main categories of DSS applied to solid waste management: the first one, based on applied mathematics, emphasises application of statistical, optimisation or simulation modelling. The second category of DSS provides specific problem-solving expertise stored as facts, rules and procedures. In addition, there are also hybrid approaches. Recently, there has been a major shift towards Life Cycle Assessment (LCA) computer-aided tools. LCA is a holistic approach that is increasingly utilised for solid waste management especially in the decision-making process and in strategy-planning. LCA can be categorised as a hybrid approach since it utilises equations for inventory analysis and recycling loops on the one hand, while on the other it requires expertise input for impact assessment and characterisation. Life Cycle Assessment (LCA) is a holistic approach that quantifies all environmental burdens and therefore all environmental impacts throughout the life cycle of products or processes (Rebitzer et al. 2004). LCA is not an exact scientific tool, but a science-based assessment methodology for the impacts of a product or system on the environment (Winkler & Bilitewski 2007). It is increasingly utilised for solid waste management systems especially in the decision-making process and in strategy-planning. LCA has been utilised for sustainable MSW management since 1995 (Guereca et al. 2006). LCA is an ideal tool for application in MSW management because geographic locations, characteristics of waste, energy sources, availability of some disposal options and size of markets for products derived from waste management differ widely (White et al., 1997; Mendes et al., 2004). LCA can help reduce local pressures and waste management costs, while considering the broader effects and trade-offs felt elsewhere across society (Koneczny and Pennington, 2007). The LCA procedure has been standardized in 1998 and revised in 2006 (ISO 14040, 2006). Based on this standard, LCA consists of the following four sections:

PurposeTwo life cycle assessment (LCA) studies comparing a new low-particulate-matter-emission disc brake and a reference disc brake were presented. The purpose was to identify the difference in potential environmental impacts due to a material change in the new disc brake parts. Additionally, the validity was investigated for the simplification method of omitting identical parts in comparative LCA. This was done by comparing the results between the simplified and the full LCA model.MethodsThe two disc brakes, new disc brake and reference disc brake, were assessed according to the LCA ISO standards. The ReCiPe 2016 Midpoint (hierarchist) impact assessment method was chosen. Simplifying a comparative LCA is possible, all identical parts can be omitted, and only the ones that differ need to be assessed. In this paper, this simplification was called comparative LCA with an omission of identical parts.Results and discussionThe comparative impacts were analysed over seventeen impact categories. The new disc brake alternative used more resources during the manufacture of one disc compared to the reference disc brake alternative. The shorter life length of the reference disc demanded a higher number of spare part discs to fulfil the same functional unit, but this impact was reduced due to material recycling. The new disc brake impacts were connected primarily to the coating and secondly to the pad manufacture and materials. The validity of the simplification method was investigated by comparing the results of the two LCA models. The impact differences were identical independent of the LCA model, and the same significant impact categories could be identified. Hence, the purpose of the study could be fulfilled, and the simplification was valid.ConclusionsBoth LCA models, simplified and full, revealed that the new disc brake had limited environmental advantages. The omission of identical parts made it more challenging to determine if an impact was significant or insignificant. The simplification seemed to be reasonable.

Nutrient circularity from waste to fertilizer: A perspective from LCA studies.

Life cycle assessment (LCA) is a vital tool for evaluating the environmental burden of solid waste. This study investigated the outcomes of selected studies that applied the LCA methodology in assessing the environmental consequences of solid waste management (SWM) systems in Africa. Thirteen process-based LCA studies on SWM were reviewed, drawing from established criteria in databases such as SCOPUS, Elsevier, and Google Scholar. These studies were distributed across various African countries, with three conducted in Mauritius and Nigeria each, two in Zimbabwe and South Africa each, and one in Tanzania, Ghana, and Uganda, respectively. The evaluated parameters included aspects such as goal and scope, functional unit, system boundary, impact assessment categories, and sensitivity analysis. The findings revealed that majority of the studies employed similar waste management scenarios to determine the most environment-friendly, yet they differed considerably in some parameters. Climate change and global warming were the most assessed impact categories. Municipal solid waste (MSW) and plastic waste were the leading waste categories. MSW typically comprises paper, bottles, metal, plastics, glass, organics, and mixed waste proportions. The study also stated that the lack of reliable data on solid waste was a significant challenge faced by African countries in LCA studies. The paper’s findings highlighted that a significant number of the studies, particularly in Nigeria, did not incorporate sensitivity analysis into their assessments, a crucial component for result interpretation. Consequently, the study emphasizes the importance of conducting more LCA research studies in African countries to produce pertinent data on SWM.

Industrial symbiosis, representing resource sharing and byproduct use among colocated firms, is a key concept of industrial ecology. Local co-operation in industrial symbioses can reduce raw material use and waste disposal, but material and energy flows extending outside symbiosis boundaries can cause considerable environmental impacts. These external impacts are often ignored in industrial symbiosis studies. In this study, we compared process, hybrid and input-output life cycle assessment (LCA) approaches in quantifying the overall environmental impacts of a forest industrial symbiosis, situated in Kymenlaakso, Finland. Conclusions from an earlier process-LCA were strengthened by the use of hybrid-LCA as local emissions were found to cause less than half of the global impacts. In some impact categories, the whole impact was caused by supply chain emissions (land use, metal depletion and ozone depletion). The cutoff in process-LCA was found to be less than 25%, except in metal depletion and terrestrial ecotoxicity. Input-output LCA approximated hybrid-LCA results well in most impact categories, but seriously underestimated land use and overestimated terrestrial ecotoxicity. Based on the results we conclude, that input-output based LCA can be used to analyze the global impacts of an industrial symbiosis, but a careful interpretation of the results is necessary in order to understand the influence of aggregation and allocation.

The influence of policy on industrial symbiosis from the Firm's perspective: A framework

Reusing industrial waste may have impressive potential environmental benefits, especially in terms of the total life cycle, and life cycle assessment (LCA) has been proved to be an effective method to evaluate industrial symbiosis (IS). Circular economy and IS have been developed for decades and have been successful in China. However, very few studies about the environmental benefit assessment of IS applied by LCA in China have been conducted. In the current article, LCA was used to evaluate the environmental benefits and costs of IS, compared with a no-IS scenario for four environmental impact categories. The results showed that four environmental benefits were avoided by the 11 symbiosis performances, namely, 41.6 thousand TJ of primary energy, 4.47 million t CO2e of greenhouse gasses, 19.7 thousand t SO2e of acidification, and 81.1 t PO4(3+)e of eutrophication. Among these IS performances, the comprehensive utilization of red mud produced the most visible benefit. The results also present that energy conservation was the distinctive feature of IS in China.