The evolution of waste management : Learning from the past to plan for the future

Improving waste and resource management around the world can halve the weight of plastics entering the oceans, significantly mitigate global heating and contribute directly to 12 of 17 SDGs. Achieving such results demands understanding and learning from the historical evolution of waste and resource management practices. I have worked on policy, strategy and evidence for both municipal solid waste management (MSWM) and hazardous waste management worldwide through six decades; so have witnessed (and contributed to in a small way) the gradual stepwise evolution from a baseline of uncontrolled disposal to modern waste and resource management.

As I approach the twilight of my career, I set out to write my ‘magnum opus’. I believe it is necessary to understand how waste and resource management has evolved in the recent past, to plan confidently for the future and to avoid ‘reinventing the wheel’. The first two parts attempt to document and analyse steps in sector evolution between 1970-1990 and 1990-2020. Drawing on my own memories and experiences and my personal library, with literature reviews to fill in the gaps, the paper gives a contemporary witness account of how the sector has evolved over time. The third part uses the historical review, and my work over the last 15 years on distilling and setting global priorities, to reflect on directions of travel and upcoming priorities.

I want this work to be widely read by policymakers and practitioners, as well as academics, so I rejected offers to write a book that few could afford to buy, and instead chose to write an open access paper as part of the 40th anniversary virtual special issue of the ISWA journal Waste Management & Research. I have endeavoured to make the paper easily readable and accessible, enabling people to dip into whatever part is their current interest.

My analytical framework uses two recent tools that I have contributed to the development of. In Figure 1, two ladders show stepwise progression of service levels for waste collection and of control levels for recovery and disposal, which underpin the Waste Wise City Tool used in reporting on SDG indicator 11.6.1. In Figure 2, the nine development bands (9DBs) theory of waste and development helps to understand the current status of waste and resource management globally, and the key stages in the stepwise progression that have been experienced up till now.

Related article: The significant potential of better waste and resource management for climate mitigation

I started work in the sector in summer 1974, within weeks of the UK’s first environmental control legislation, the Control of Pollution Act. The baseline was near 100% collection of mixed waste in urban areas (the basic level of service in Figure 1a), with no or limited control over disposal of either MSW or hazardous wastes (Figure 1b). So, the initial priority was to bring wastes under control, moving to the basic level of controlled (recovery or) disposal, as illustrated by a 1970s UK controlled landfill in Figure 3. My doctorate was on planning for MSWM; I can still recite the objectives as a sort of mantra: what facilities do we build, where do we build them and how big do we make them. It was very much the ‘technical fix’: how to meet the legislative standards of environmental control at least cost.

By 1980, some of the most developed countries had reached what we now call the new target baseline of DB5 (Figure 2). They began to ramp up standards, e.g. on landfill leachate and gas control, moving through improved to full control (Figure 1b) during the 1980s and beyond. Figure 2 distinguishes two alternate pathways for the developing standards (DB6 and DB7), each achieving full control or environmentally sound management (ESM). DB6, the pathway followed by the US and UK, focused on market oriented systems to meet increasing legislative standards at least cost, which resulted in continued reliance on landfill. DB7, the pathway followed by North and Central European countries and Japan focused early on developing high recovery systems, typically involving incineration with electricity generation and heat recovery, driven by prescriptive technical regulations rather than market outcomes. A similar dichotomy of approaches to achieving high standards was also observed for hazardous wastes.

By the 1990s, people were beginning to recognise that an approach focussed primarily on the ‘technical fix’, based on technologies within a strictly enforced legislative framework, was not sufficient on its own. In the Global North, new MSW landfill and incineration facilities to meet ESM standards were becoming increasingly expensive and beyond the technical capacity of (small) municipal governments. Attempts to achieve economies of scale through inter-municipal co-operation, and to access technical capacity through contracting out to the private sector, likely exacerbated strong local opposition to new mega-facilities (not in my back yard – NIMBY). Also, the 1991 UN Framework Convention on Climate Change made methane from landfill into a climate issue.

So, recycling of MSW (both dry materials and e.g. composting of the wet, putrescible organics such as food and garden wastes) was being rediscovered, not so much as a source of revenue but more as an alternative, potentially cheaper waste destination or ‘sink’. Various economic, social and information-based instruments were developed to provide a balanced basket of policy instruments, enabling a more integrated approach to improving the levels of collection service, collecting several source-segregated fractions (Figure 1a) to facilitate diversion of waste to recycling or more generally ‘up the hierarchy’, and of biodegradable waste away from landfill. This extended the two distinct development pathways in Figure 2, reaching DB8 (from DB6) and DB9 (from DB7). Solid waste management was evolving into waste and resource management.

The 1970s baseline in the Global South was rather lower and progress has generally been much slower. My first field trip in 1983 was to Bangkok, where the MSW collection service coverage was around 80% (DB3 in Figure 2) with most collected waste going to three huge dumpsites (Figure 4). Worldwide, uncontrolled disposal and open burning was the norm, with waste collection in major urban areas often 30-60% (DB2), with 0-30% (DB1) elsewhere. The local public health and environmental impacts of unmanaged and mismanaged MSW were increasingly severe. Recycling rates were often higher than in the Global North thanks to an active informal sector, particularly in parts of Asia.

Attempts to export technologies designed for American, European or Japanese wastes, regulatory systems, cultures and income levels, often resulted in failure. Constraints to taking the first steps of extending MSW collection coverage and controlled disposal (moving gradually from DB1 to DB4 and DB5) were being identified as institutional and financial rather than technical. This led to a new paradigm, integrated sustainable (solid) waste management (ISWM), which I use to analyse progress from the 1990s. The first triangle in Figure 5 shows technical factors, the ‘hard’ components required for physical management of wastes, the ‘what to do’. The second shows ‘soft’ or ‘governance’ aspects, required to make that happen in practice, the ‘how to do it’: inclusivity of stakeholders (particularly service users and providers); financial sustainability; and sound institutions and pro-active policies at both national and local level. That said, politicians do like ‘modern’ technology, and efforts to promote a more integrated approach in the Global South have always been in competition with an army of technology salespeople – I led several 1990s projects that failed due to the promise of an alternative ‘magic solution’.

My current best estimate (albeit still hampered by unreliable data) is that, despite much recent progress, around 2.7 billion people, more than a third of the world’s population, lack access to a waste collection service; while some 40% of MSW that is collected ends up in uncontrolled disposal sites or is openly burned. This is an ongoing global waste emergency requiring concerted, urgent action.

Understanding this evolution of waste and resource management (WaRM) over the last 50 years is important when looking forward. The waste problem has absolutely not been ‘solved’. Even in the Global North, much remains to be done, both in terms of consolidating high levels of collection service and ESM for recovery and disposal; and of moving beyond ESM and recycling towards waste prevention and a truly circular economy (‘DB Zero’ in Figure 2). It is important to remember that waste and resource management as we know it only exists due to effectively enforced legislation; creating a ‘level playing field’ to attract investment in higher standard facilities and practices, without fear of being undercut by other facilities operating to lower standards or indeed by waste criminals. Challenges include achieving clean ‘cycles’ which avoid the accumulation of hazardous substances, recognising both limits to recycling and the continuing need for final sinks; and ‘new’ waste streams, e.g. electric car batteries, solar panels etc, for which both 3Rs (reduce, reuse, recycle) and ESM approaches have yet to be (fully) developed.

The priority in much of the Global South remains to bring wastes under control: both to extend MSW collection to all and phase out open dumps and open burning (achieving SDG indicator 11.6.1 and DB5), and to keep hazardous wastes separate from MSW and manage them in an environmentally controlled way.

With challenges come opportunities. I led work on UNEP and ISWA’s first (2015) Global Waste Management Outlook. We showed that the economic costs to society of unmanaged wastes exceed the financial costs of universal collection and controlled recovery or disposal (SDG 11.6.1, DB5) by a factor of 5-10. We showed that improving waste and resource management would contribute measurably to six SDGs (including SDG13, climate action), directly to a further six and indirectly to the remaining five; but we largely failed in our aim to increase its political priority. That changed in 2017/18 when Sir David Attenborough finally broke through to global consciousness on the tragedy of plastics entering the oceans. My best estimate is that extending basic waste collection and controlled disposal to all would cut in half the mass of plastics entering the oceans, while reducing open burning of wastes by >90%. As a result, ‘plastics initiatives’ are already a major source of funding for MSWM development projects. Current negotiations to develop a legally binding global instrument on plastics pollution (the ‘plastics treaty’) arguably places waste and resource management firmly on the international agenda. The same can be said of establishing an international science-policy panel on chemicals, waste and pollution prevention (SPP), modelled on the IPCC for climate change. However, there is much work to do to ensure that the final negotiations in 2024 on the plastics treaty and the SPP focus not only on the 3Rs/circular economy, but also recognise the importance of enabling the Global South finally to bring MSWM under control.

Sustainable financing

Sustainable financing remains a challenge for residual waste management facilities in the Global North, particularly in countries like the UK and US which rely more on market forces (development pathway DB6-DB8). In much of the Global South, the financial costs of even basic services for MSWM are unaffordable locally, but the economic benefits of reducing plastics pollution and mitigating global heating are felt worldwide; so a global initiative is required to develop tailored and innovative financing mechanisms (including ‘climate’ and ‘plastics’ finance) to extend services to under-served communities. Traditional international development finance has focused on capital investment costs for full control (ESM) recovery and disposal facilities (Figure 1b). But over a period of years, operational and maintenance costs often exceed investment costs; investment in basic control facilities may be required as an interim step; and collection costs often exceed recovery and disposal costs. So it is important to consider all aspects of sustainable financing.

Rethink sustainable recycling

In the Global North, the MSW recycling system, which has been rebuilt from a low base over the past 30 years, is broken. Focus needs to shift from increasing the supply of materials, as measured by quantities collected for recycling, to increasing demand and the quality and quantity of materials actually recycled. Targets need to be set not just on weight, but also on carbon.

In the Global South, the baseline is quite different, with active informal sector recycling often operating in parallel to formal city MSWM. Here, rethinking means first, combining existing formal MSWM and informal recycling into one integrated WaRM system and involving informal recyclers as a key stakeholder group. Second, modifying the 9DBs roadmap as followed in the Global North to leapfrog the ‘basic’ level of collection service (Figure 1a), moving directly to an ‘improved’ or ‘full’ level of service collecting two, three or more source segregated fractions. The benefits should be a win-win-win: extended collection coverage; less waste requiring controlled disposal so less investment required; and more jobs with better working conditions for both formal and informal waste workers.

EPR with teeth

More responsibility must be placed on the ‘producers’ (manufacturers and supply chain) who place products or packaging on the market, including all products containing chemical substances of concern. Where extended producer responsibility (EPR) (or product stewardship) is already present, to work more effectively it needs to be given ‘teeth’ rather than just ‘gums’. The producers need to: cover all the end-of-first-life costs of collecting, sorting and recycling their products and of managing any residual wastes; meet progressively increasing recycling targets; and take full responsibility to ensure that recycling both can and actually does take place in an environmentally sound (ESM) way. A well-designed EPR scheme must incentivise product design to: reduce waste quantities; facilitate disassembly for easy repair, reuse, and recycling; and minimise use of difficult-to-recycle materials.

It is the municipalities and informal recyclers in the Global South who are most in need of financial and other support from the producers to manage end-of-life products and packaging on their behalf, and who are most impacted by their mismanagement. But many lower income countries have GDPs less than the revenue of a large transnational fast-moving consumer goods corporation (FCMG); so EPR needs to be implemented in a coordinated way across the world, with regional or even global mechanisms for negotiation.

Implementation of these three priority policies would go a long way to addressing the global waste emergency of billions of people still without even basic MSWM services. The traditional ‘top-down’ approach to development, working through national governments, gradually building capacity, and focusing on (larger) investments in infrastructure, will take many years to reach the poorest communities. So a parallel, complementary, ‘bottom-up’ approach is also required, working with NGOs and communities themselves, and putting people at the centre of the narrative. Sustainable waste and resource management needs to work for the poorest people, providing both a quality service which keeps low-income and slum areas clean and healthy, and a decent livelihood for the multitude of workers who deliver collection and recycling services and EPR on behalf of producers (Figure 6).

Achieving controlled disposal of residual wastes at an affordable cost remains a major challenge. One issue is an ambiguous attitude to the acceptability of the ‘basic’ level of control (Figure 1b), which was used as a first step in the Global North in the 1970s. Many international donors require, and indeed national governments legislate for, best practice – full control – ESM standards. The outcome is often perverse – an insistence on full control in effect allows no control to continue, particularly in secondary cities and rural areas. What is urgently needed is innovation in governance, service delivery and relatively simple technologies that would facilitate local officials making affordable, incremental improvements and replacing or upgrading existing dumpsites to intermediate basic-control landfills suitable for reaching SDG 11.6.1 compliance.

When I first stumbled into waste management in 1974, I did not expect still to be here nearly 50 years later. I have stayed because my international work on policy, planning and the evidence base has constantly evolved, bringing interesting new challenges and opportunities. Because of plastics pollution, those are greater now than ever; the early 2020s may be a ‘tipping point’, when my ‘baby’ has ‘come of age’ and is emerging at last onto the world stage as a global priority. But I do need to continue handing on the baton to the next generations of waste and resource management practitioners: I have written my ‘contemporary witness’ account for you. Please do download and dip into it – I hope you find inspiration.

You can download David C. Wilson’s December 2023 paper, ‘Learning from the past to plan for the future: An historical review of the evolution of waste and resources management 1970-2020 and reflections on priorities 2020-2030 – The perspective of an involved witness’ from the Waste Management & Research website.