There is a critical need to tackle process emissions from anaerobic digestion facilities, to promote environmentally sustainable treatment whilst continuing to generate biogas and biosolids for beneficial use. To deliver the most beneficial environmental outcomes, resources and investment should be targeted towards assets that pose the greatest emission potential.

In collaboration, Thames Water and AtkinsRéalis have developed a Risk-Based Approach for assessing bioresources flowsheets and identifying targeted interventions to reduce process emissions, increase treatment resilience and comply with permit requirements within the Industrial Emissions Directive. This approach considers a hierarchy of emissions in order of greatest environmental concern: i) greenhouse gases; ii) ammonia emissions; and iii) odour and nuisance emissions. This approach was developed during a practical assessment of Bracknell Sludge Treatment Centre which serves over 90,000 people. Bracknell's assessment combined extensive monitoring data by Thames Water with complementary emission modelling from AtkinsRéalis to provide robust, evidence-based recommendations for asset interventions.

Specific learnings gained during the Bracknell assessment during the development of this Risk-Based Approach provide insight into the critical next steps required to mitigate process emissions. This offers a framework to focus resources and investment to meet the challenges of the Industrial Emissions Directive and deliver resilient, low emissions bioresources centres which are fit for the future.