Food waste co-digestion with sewage sludge – Realising its potential in the UK

The application of anaerobic co-digestion of food waste with sewage sludge, although well established in many European countries, is still in its infancy in the UK. This process has many benefits to offer, with a successful application often associated with increased renewable energy potential, outweighing constraints associated with the variability of food waste and its handling requirements prior to co-digestion. With both regulations and water infrastructures designed and constructed on the basis of linear views and sectorial requirements and conditions and technologies from the past in many parts of the world, in the UK, sewage sludge and food waste digestion operations are also under very different regulatory and management regimes. With sustainability requiring that we do not address single issues in isolation, but through a systems approach that delivers integrated solutions, co-digestion of food waste with sewage sludge could become such a solution. If carefully applied, co-digestion can deliver beneficial synergies for the water industry and authorities responsible for food waste management. The collaboration of all relevant stakeholders and regulators to support changes to current regulatory frameworks to enable this, is proposed as the way forward, particularly as their complexity has been identified as the major hurdle to the implementation of co-digestion in the UK.

► Food waste co-digestion with sewage sludge is still in its infancy in the UK.
► The benefits of co-digesting food waste with sewage sludge outweigh the constraints.
► In the UK the application of this process looks to be complex and unclear.
► Regulations have become the major hurdle to its implementation in the UK.
► Collaboration between stakeholders and relevant authorities is recommended for the UK.