Waste and resource management remains a complex societal issue with different world regions at very different stages of the transition to a more sustainable model of economic growth and consumption. While the world's governments generally acknowledge the impact that humanity is having on, particularly, climate change, the ability of policymakers to drive change remains challenging. However, the integrated nature of ‘life’ is evidenced in the three papers in this edition, showing how academic research can shine a light on current practices and bring experience from other regions to improve local conditions.
Waste as a resource has long been recognised, particularly regarding municipal solid waste. European legislation has dramatically improved recycling rates (notably in the UK) but as they are typically based on weight metrics this has often driven recovery of more dense materials, especially wet materials such as green (garden) waste and metals, to the detriment of less dense materials, such as plastics, which take up much more space. While waste transport is constrained primarily by weight of vehicles that are allowed on roads, landfill is constrained by volume (it is void space that defines the final contours of a landfill, not the tonnage disposed of). The flip side of this is energy recovery, where plastics have a high energy content relative to wet dense materials, but shredding as a pre-treatment is often required to try to reduce volume. Therefore, waste composition and collection systems can have an impact on how governments determine which waste management policies are right for their location, state of economic development and vision for sustainability.
The ‘prevent – reuse – recycle – recover – dispose’ model enshrined in EU law in 2008 can trace its roots back to the 1975 version of the Waste Framework Directive, when waste prevention, recycling and ‘possibly’ energy recovery were to be ‘encouraged’ by member states. Over 45 years later these founding principles are still valid, but how to implement them remains a local challenge.
Intuitively, a fully integrated approach to waste management would be the best result: product producers would design products that prevented waste during manufacture and use and that facilitated easy reuse or recovery of all the components at the end of the product's life; consumers would recycle as much waste as possible, reduce food waste in general and minimise residual waste for disposal; while those responsible for waste disposal would recover value (both materials and energy) from waste and reduce to a minimum the amount of non-recyclable waste that requires some form of final disposal. However, such approaches are complex and costly and there is no ‘one size fits all’ approach that works because of the interaction between environmental, social and economic factors. What is good for the environment often has an economic impact that society isn't yet ready to accept.
Currently, the impact of societal and economic pressures is becoming increasingly clear, where events in Ukraine are having worldwide impacts, causing concerns such as the ‘cost of living crisis’ that, for many, are far more pressing than waste management priorities. While these pressures may change consumption patterns, the longer-term consequences for the wider environment are less clear. Consequently, researchers will have to keep investigating all aspects of waste management policy and practice around the world so that learning can be shared and hopefully applied to the benefit of all.
The literature review of best practice in Brazil (Olivo et al., 2022) highlights the multi-dimensional nature of waste management in terms of the actors involved and the frameworks within which they operate. However, by applying sustainable integrated approaches better outcomes are achieved and the paper proposes guidelines for implementation. Such approaches reduce the amount of waste requiring landfill, but it is likely that some form of landfill is going to be required in many parts of the world for many years to come. Consequently, in areas where seismic activity is a risk, landfill location and design, as well as the characteristics of the waste to be landfilled, need careful consideration to prevent long-term environmental risk, which is considered in a numerical analysis paper from Iran (Azhari et al., 2022). While in the UK sewage sludge is usually treated by the local water utility company, in other regions dewatered sewage sludge can be and is directly landfilled. A genomic study from Russia (Dregulo et al., 2022) considers how the varying microbial populations in sewage can negatively impact landfills and proposes policy changes including regulation and bans to improve the environmental and sanitary standards when landfilling sewage sludge or using it as a fertiliser.
