Mechanical engineers urge ‘radical rethink’ of UK waste hierarchy

Yesterday (5 September), The Institute Mechanical Engineers (IMECHE) issued an update to its 2009 report Waste as a Resource, urging a reassessment of the UK’s waste hierarchy.

IMECHE report waste hierarchy

Echoing recommendations put forward in the original document, Waste as a Resource: A Sustainable Way Forward calls on the Government to abandon its current approach to the hierarchy, with the view of waste as a problem. Rather, it proposes a reinterpretation of the waste hierarchy from a ‘Waste as a Resource’ (WaR) perspective.

The UK waste hierarchy

Adopted in the 1990s to support environmentally-minded decision-making and climate change mitigation (CCM) in waste management, the waste hierarchy progresses as follows: prevention, re-use, recycling, other recovery, and disposal. The updated report, however, aims to prove that the hierarchy does not deliver such mitigation for which it was designed.

In 2009, the Institute’s first report demonstrated that the waste hierarchy, first adopted in the 1990s, was not suitable for achieving the Government’s commitments for 2020 on emissions and energy.

The IMECHE now claims that, had the recommendations laid out in the original report been adopted into UK waste, energy and emissions policies, they would have been much more effective in aiding the country in meeting its sustainability targets. Further, the country ‘could now have a more clearly-defined and sustainable future ahead as it faces highly ambitious Net Zero emissions targets for 2050.’

In particular, it first claims that the hierarchy doesn’t encourage the necessary levels of waste reduction. Reductions are found often as a result of redefinition of what constitutes ‘waste’, rather than the genuine prevention of waste.

The body also shares that ‘reuse’ has not yet been widely practised in the UK, and is unlikely to in a society where it is much cheaper to replace than to rather repair, refurbish, or renovate.

The report observes that recycling, the hierarchy’s third tier, has not been a well-designed area of policy by the UK Government to achieve CCM. Importantly, demand for recycled material can vary, meaning large stockpiles of it often go unused. 

IMECHE also notes that energy recovery has been mistaken by the Government and NGOs for incineration. Consequently, due to animosity towards the latter, energy recovery has been an unused option within the hierarchy.

Finally, the Institute observes, the rejection of disposal of waste continues in large quantities, and plans to rule out landfills are often abandoned. For example, in 2019 the Scottish Government deferred its 2021 landfill ban to 2025, and may even struggle to meet that based on current performance.


In light of these issues, the IMECHE concludes its newest report with five key recommendations in order to strengthen the hierarchy to better meet its purpose. This can first be achieved, according to the body, with a replacement of the hierarchy with a model that genuinely delivers on the prevention of waste. This step, it states, is paramount to bringing the most beneficial effect to the environment.

Careful consideration must be taken towards finding solutions to various waste streams, as the report puts emphasis on the diversity of non-reusable materials, such as PET bottles and metals, which cannot be disposed of in the same way.

Emphasis is also placed on adopting a zero-to-landfill approach. The Institute, echoing the European Landfill Directive and wider environmental hazards, states that landfill is no longer an acceptable way to deal with waste. While ‘zero-waste’ is not a realistic target, effort must be made to greatly reduce the amount of waste heading to landfill, with transparent, independently audited data on the recovery and destination markets of materials can be used to achieve this.

IMECHE calls for greater emphasis on all waste streams, not just household waste. As household waste makes up only 12 per cent of all streams, legislators must take pressure to solve this limited area and shift focus to addressing industrial waste, as well as construction and demolition waste.

The new report concludes with the recommendation for the Government to use locally-produced waste to heat and power local communities. Complete community ownership of waste processes, from transporting to marketing materials, would be a positive consequence of CCM, one which is already being implemented in other European countries.