Low carbon crisps

Ever thought about the carbon cost of a packet of crisps?

At CCm Technologies they think of little else. Their revolutionary fertiliser offers a big step to carbon-free snacking. Waste from crisp factories or from sewage treatment works can be routed and treated to form the basic building blocks of new fertilisers that can be spread on the ground to grow a new harvest of potatoes - or any other crop we need. The system avoids waste and takes a big cut out of the carbon emissions of traditional fertiliser production.

In this episode, Tom Heap tours the CCm fertiliser plant on the outskirts of Birmingham and discusses the carbon benefits with Society Fellow Dr Tamsin Edwards of King's College London.

Listen now on BBC Radio 4

What our experts say

We asked Society Fellow Dr Kate Schofield from the University of Plymouth to offer some observations on the potential of fertiliser produced from waste products in reducing carbon emissions. Their points take some of the themes of the programme a step further. 

Soil fertility and land productivity are significant and yet often overlooked issues. The CCm fertiliser is not a silver bullet solution, however, the application of the CCm fertiliser product in combination with other important adaptations and improvements to land management practices has the potential for significant benefit.

What are the limiting factors?

Feedstock suitability and availability: the nature of waste materials is that they commonly vary in both characteristics and availability. Thus, the following questions/limitations may need consideration: 

• What are the criteria for a suitable feedstock?  

• Is it possible to ensure consistency between batches? One might assume that differences in the feedstock result in differences in the product. This may have implications at the point of use regarding required application rate. 

• Will there by screening processes for different feedstocks to ensure that they produce suitable (safe) fertilisers and to ensure optimal operating conditions?   

• Does the biodigestion process remove all potentially toxic elements or contaminants, in particular any veterinary antibiotics (as antimicrobial resistance is an increasingly looming issue)? 

Social acceptability and local regulations may be a factor that requires consideration with regard to global roll-out of the technology, although regulation largely appears to view such applications in a favourable light.

What are the co-benefits?

• Biogas production - (relatively) clean energy 

• Improved soil fertility  

• Increased macro and micro nutrient concentrations  

• Improved crop productivity 

  • Increased efficiency of nutrient uptake by plants

  • Suggested benefits to plant immunity to biotic and abiotic stressors 

• Circular economy - Organic waste management  

  • Controlled degradation through the biodigestion process has the potential to reduce the release of greenhouse gases compared with ‘traditional’ organic waste disposal methods. 

A further positive consideration is the scalability of these systems - this makes it easier for individual farmers up to large scale manufacturers to invest in appropriately scaled systems, as Walkers have done.

Are there any potential negative impacts of this idea?

As with any fertiliser use, careful application management is required to minimise the risk of direct and indirect harm to interlinked environments through leaching and runoff.

Whilst the process of biodigestion reduces/capture greenhouse gas emissions from the feedstock, better understanding of the longevity of the greenhouse gas retention with these fertilisers is needed in order for long-term implications to be understood. As always, more research is needed!

Further reading

• Chojnacka et al. 2019. Carbon footprint of fertiliser technologies. Journal of Environmental Management 231, pp. 962-967 

• Gonzalez-Diaz, A., Jiang, L., Roskilly, A.P., Smallbone, A.J. 2020. The potential of decarbonising rice and wheat by incorporating carbon capture, utilisation and storage into fertiliser production. Green Chemistry 22, pp. 882-894

• Food and Agriculture Organization of the United Nations. 2019. World fertilizer trends and outlook to 2022

• World Biogas Association. 2019. Global Potential of Biogas

About the series

39 Ways to Save the Planet is a new radio series by BBC Radio 4 developed in partnership with the Society and broadcast in 2021. It showcases 39 ideas to relieve the stress that climate change is placing on the Earth. In each 15 minute episode Tom Heap and Dr Tamsin Edwards meet the people behind a fresh and fascinating idea to cut the carbon.

Programme website

Over the course of 2021, the Society will be producing events and digital content to accompany the series.