Over the last ten years, a variety of pre-treatment technologies have emerged claiming to optimise anaerobic digestion. Of all these technologies, biological hydrolysis (Monsal Enzymic Hydrolysis) is the most widely adopted technology in the UK. Monsal Enzymic Hydrolysis has now been selected for eleven plants; eight operational, one under construction, and two in design, and the technology has been adopted by five water utility companies, and is currently the technology utilised at the largest Advanced Digestion plant in the UK.
Originally designed as a cost effective alternative to secondary digestion, the paper reviews the development of the Monsal Enzymic Hydrolysis process since 2002 to the present day. Current levels of performance are highlighted demonstrating biogas production of >400m3/tds, pathogen free centrifuge cake without regrowth, energy self-sufficiency, rheology conditioning,
dewaterability >28%DS and seamless plant integration. New plants under construction are presented introducing new advances such as raw cake back mixing allowing feeds of 8% and digester loadings of >4.5kgVS/m3.day.