Redefining our relationship with waste

Is the waste management hierarchy an outdated concept? Phil Purnell thinks it is and argues why we need to reassess how we think of and deal with waste

We are taught that to move up the waste management hierarchy, we must move away from disposal and embrace recycling, reuse, minimisation and ultimately prevention.

However, for these to be effectively implemented the complete lifecycle of products, from concept and design through to life after disposal, must be reconsidered.

If a product is designed from the concept stage for reuse, reduction or even easy disassembly for recycling at the end of its life, there are likely to be multiple benefits to different stakeholders, including the waste management industry and recyclate markets, as well as the environment.

The research team that I head up at the University of Leeds is evaluating a novel systems-based approach that will move away from the traditional perception that alongside the desired product/s, production processes also generate waste.

Our alternative viewpoint is that all processes generate products and co-products with varying and complex economic, environmental and social values.

One outcome of this new approach is that it is perfectly reasonable to dispose of co-products with little or no economic, environmental or social value.

In a nutshell this means moving away from the management of waste and end-of-life resource recovery to the management of value and resources at each stage of the product’s lifecycle.

Currently, most of us inhabit the recycling tier of the waste hierarchy. But there is often a failure to distinguish between the visible collection of materials for recycling/reprocessing and the actual process of recycling. Collection alone is not recycling; materials collected for recycling in the UK are often disposed of elsewhere in the world.

Also, the markets for recyclables are generally volatile, affected by a host of factors from reliability of supply to cost of raw materials. In some instances, markets are often reliant on backstreet reprocessors who engage in recycling practices that pose risks to the environment and human health, for example, waste electrical and electronic equipment reprocessing in Southeast Asia.

By adopting a cradle-to-cradle approach from concept through to final dismantling or reuse, we will be better able to understand the consequences of global markets on production systems and hence develop more resilient systems.

However, it is not always easy to define a system as many production processes overlap. Changing one process to improve its social, environmental and/or economic value might have a negative impact on an adjoining sub-system.

This will have an uncertain and complex effect on the value – economic, environmental and social – of the entire system. Understanding how the boundary to a system is drawn is therefore an important consideration for all “design of disposal” assessments.

Systems can be designed to optimise the multifunctional value of any outputs. Such an approach embraces the ethos of the circular economy but does not slavishly advocate a zero waste strategy – there may always be outputs for which disposal will be the best way to minimise environmental, social and economic impacts.

It is important that we replace the waste management hierarchy with a complex value-based system that allows us to see the bigger picture, enabling joined-up thinking between resource management, economic drivers, social wellbeing and environmental impact.

Thanks to a Natural Environment Research Council catalyst grant from the resource recovery from waste programme, the research team at Leeds has just started this work.

The plan is to develop a framework over the next three years which can be used to understand the optimum economic, environmental and social values of different systems that might once have looked to the waste hierarchy for their end-of-life management.

Phil Purnell is Professor of Materials and Structures at the University of Leeds

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