Plastics are increasingly a preferred material choice in designing and developing complex, consumer products, such as automobiles, because they are mouldable, lightweight, and are often perceived to be highly recyclable materials. However, actually recycling the heterogeneous plastics used in such durable items is challenging, and presents very different scenarios to how simple products, such as water bottles, are recovered via curbside or container recycling initiatives. While the technology exists to recycle plastics, their feasibility to do so from high level consumer or industrial applications is bounded by technological and economical restraints. Obstacles include the lack of market for recyclates, and the lack of cost efficient recovery infrastructures or processes. Furthermore, there is a knowledge gap between manufacturers, consumers, and end-of-life facility operators. For these reasons, end-of-life plastics are more likely to end up down-cycled, or as shredder residue and then landfilled. This paper reviews these challenges and several alternatives to recycling plastics in order to broaden the mindset surrounding plastics recycling to improve their sustainability. The paper focuses on the automotive sector for examples, but discussion can be applied to a wide range of plastic components from similarly complex products.

The circular economy re-interprets the recovery of materials by promoting designing out waste from products, retaining materials for reuse, and emphasizing key elements universally accepted for sustainability. The current efforts to target, isolate, and reduce single-use items, particularly plastics, have only recently begun in earnest. Unfortunately, the recovery and recycling of materials have been disrupted by global market uncertainty, and recently, the COVID-19 pandemic. While the pandemic and its impacts complicate materials recovery, the core of the circular economy still depends on efficiently capturing and returning spent materials for production. Arguably, our perception and common understanding of the recovery process is influenced significantly by the recycling of simple consumer products, such as plastic bags and beverage bottles. However, there are greater difficulties when managing multiple materials from significantly more complex consumer products, for example, from end-of-life vehicles. This paper presents an overview of how waste recovery-related issues vary between simple versus complex consumer products. Using food packaging, tires, cell phones, furniture, and end-of-life vehicles as examples, this paper provides a commentary on the challenges facing complex product recovery compared to simple consumer products in the Canadian context in order to establish how this classification concept can be beneficial for describing a given product and its materials recovery prospects. A categorization framework is developed and applied to these case study products to provide a relative comparison of product complexity.

The state of brownfield remediation and rehabilitation approaches continues to advance significantly, particularly with respect to the types of brownfield technologies available for assessing and treating contaminants. However, largely absent is a structured means for integrating the objectives of multiple stakeholders (e.g., municipality, developer, regulator, community) comprehensively by using a classification method that can differentiate among the brownfields based on an overall suite of relevant characteristics—such as community issues, site characteristics, development potential, and financial viability—and analyze them categorically. Existing brownfield scoring schemes, ranking methods, and identification approaches that were developed in the past by various organizations can be used as classification mechanisms, but many of these systems are designed for a specific group of stakeholders or jurisdictions and cannot be used to evaluate situations outside their intended original use. Nevertheless, they provide useful starting points to consider what the desirable elements are within a comprehensive classification system. This article reviews 12 contemporary brownfield classification systems and analyzes their strengths and weaknesses. It concludes that the lack of a multidisciplinary approach in the development of the existing classification systems limits their use on a broader scale. Lastly, the article establishes the need for a broader multidisciplinary classification system that can serve as a basic framework for systematic decision making regarding brownfields.

Life Cycle Assessment (LCA) is a widely used tool to measure the environmental sustainability of products or processes. Integrating LCA into the assessment of waste diversion strategies recognizes that current waste diversion strategies are insufficient to stem the global impacts of waste effectively. The increased pressure to divert organic and inorganic materials to reduce landfills impacts and promotes the circular economy. Historically, waste diversion efforts in municipalities and industries focused on higher-profile inorganic wastes, such as plastics and other recyclables. However, organic waste is increasingly identified as a key waste fraction that must be effectively managed and regulated. This research surveys published LCAs from 2019 to 2023 focusing on the anaerobic digestion (AD) of organic waste. Notable conclusions include the lack of studies comparing AD with the latest treatment options such as co-gasification; the insufficient attention to the LCAs on biogas upgrading methods; and the monetization of LCA results using carbon credits. In addition, more than 50% of reviewed LCA studies concluded the results with a sensitivity analysis, which was not a common practice before 2019 in LCA studies on anaerobic digestion. This signifies the increasing need to understand uncertainty in the circumstances governing applying AD to wastes. Finally, neglecting the combined effect of several parameters in the sensitivity analysis might have reduced the accuracy of the sensitivity analyses in the reviewed LCAs. Overall, LCAs conducted on AD-related applications vary widely in terms of scope and consistency, implying that the outcomes may not be as applicable as intended. The identified challenges, issues, and other findings related to this research are expected to help standardize LCA procedures as applied to AD to promote greater comparability.