Anaerobic Digestion (AD) is a biological process which degrades organic material to generate
biogas and a stabilised, nutrient rich residue. The UK Government recognises the importance
of AD in meeting its environmental and renewable energy targets and has introduced
incentives to support and develop the industry. The rate limiting step in AD is the bacterial
hydrolysis (solubilisation) of the feedstock which is very slow compared to the subsequent
conversion to methane. Readily biodegradable materials (i.e. food waste) hydrolyse rapidly,
giving a good conversion to methane. However many substrates such as crop residues, silages
and manures contain slowly hydrolysable material (i.e. cellulose, ligno-cellulose) resulting in
reduced methane yields. It is therefore highly desirable to enhance the hydrolysis step to boost
biogas yields, improve performance and increase revenue.
Aqua Enviro identified that a novel pressurised microwave hydrolysis process developed by
York Biorenewables Development Centre (BDC) to breakdown energy crops for fermentation
to biofuels, could be used to pre-treat complex AD feedstock in order to boost process
efficiency. BDC and Aqua Enviro carried out initial self-funded tests demonstrating dramatic
increases in biogas yield of up to 340% when pre-treating maize silage. Such increases would
revolutionise the AD sector by; accessing new feedstocks, making AD viable at smaller scale
and improving AD economics. Aqua Enviro wishes to develop and introduce this technology
into the market. This Proof of Concept project aims to produce a robust scientific appraisal
and full business case for this technology to enable funding/industrial partners to be secured
for its widespread commercialisation. This will comprise MW pre-treatment of a range of
feedstock types under varying conditions and AD process assessment via laboratory scale
bench trials. The outputs of this project will justify the investment to move up to full-scale
demonstration trials.