Stantec’s Chris Hudson on digesting the food waste facility need

Chris Hudson is technical lead, waste and energy transition at Stantec

Around half of English councils currently collect food waste, and the steep increase due to be mandated will represent a step change.

This is good news for the environment, with the hope being that it makes food waste collection as normalised as paper or glass recycling, while also producing useful biogas. But put simply, England may not have enough sites to treat the waste. To enable more investment in new treatment facilities to come forward, we need to demystify anaerobic digestion (AD) – a natural process whereby waste is placed in a sealed ‘digester’ that starves the material of oxygen and micro-organisms in the waste break it down.

AD treatment facilities are the main way of managing food waste in England. AD plants are currently built via private investment in response to demand and can take many years to pass through planning and construction. Although their utility and benefits far outweigh any potential impacts, local communities often oppose new facilities, and approval and development can be far from simple.

With a potential wave of new demand coming in a very short time, Stantec expects a significant increase in AD investment and capacity will be needed if we are to reap the benefits of segregation of food waste at source. While this could be seen as a looming problem, it is better to look at this as a major opportunity for growth and local investment.

Food for thought: investment in treatment works will be needed to meet new regulations on food waste collection

Food waste is not a good traveller, so AD plants are best located near points of waste collection. Lower AD coverage can often overlap with places of higher economic need – where under-resourced councils might not prioritise food collection – so new investment in facilities and the employment they bring could be especially beneficial.

Properly managed, AD treatment is an eco-friendly way of dealing with food waste. It stops the free release of methane to the atmosphere, which is common in composting and landfill, and allows the waste to be used to generate biogas, which can be used to replace natural gas in the national network. While the AD process can cause some limited methane release, with the correct mitigations in place, it remains an efficient form of reducing emissions. AD sites already help to cut 1% of the UK’s carbon emissions every year and with more capacity, the sky is the limit.

Wider waste treatment challenges

More AD coverage could also help us with wider waste treatment challenges as the AD process can also be used to treat commercial biowaste, agricultural waste and waste water. Guidance does not currently allow for them to be treated (‘co-digested’) together. If this can be changed at a national level, it could significantly increase the ability for new capacity to be co-ordinated and delivered at scale across the country. In some cases, industrial waste that currently goes into our sewer system may even be able to be collected and redirected to these plants. This would all help to generate economies of scale – incentivising treatment providers to invest in bigger, better sites able to accommodate all these types of waste.

England needs much greater awareness of the importance of food waste treatment, and its added benefits, to derisk the delivery process and incentivise providers to build more much-needed capacity. This is achievable, but will require co-ordination between the waste sectors as well as local and national governments. It will also take a step change in public opinion – an acknowledgement of the need for local treatment works and a willingness to get to grips with this under-appreciated but vital system of infrastructure.

Chris Hudson is technical lead, waste and energy transition at Stantec