Thermal Hydrolysis Advanced Pre-treatment pilot rigAdvanced pre-treatment technologies are used to treat feedstocks prior to anaerobic digestion to enhance the rate of degradation with the aim of providing greater biogas yields and improved dewaterbaility of the digestate.  In 2006 Aqua Enviro invested in a Thermal Hydrolysis pre-treatment pilot ri and now in 2010, the business has over 3,000 "trial days" of data from operating both enzymic and thermal hydrolysis advanced pre-treartment trials. 

The pilot scale unit is the only one of its type in the UK and has been in constant demand.  It is comprised of a steam generator with injection heating pump and heating element, the reactor with sample holder, the flash tank with the scrubber and carbon filter, plus associated pipe work, valves and instruments.  Raw sludge is subjected to intense heat and pressure, typically 165^oC and 6 Bar for 20-30 minutes, during which time the cell structure is disintegrated into an easily digestable feed. 

The process increases the amount of methane generated from the downstream anaerobic digester along with the quantity of volatile solids destroyed.  Combined with reduced odour, better dewaterability and an end product that is pathogen free thermal hydrolysis is becoming a real option as part of an integrated sludge treatment strategy.  The exact costs and benefits do however vary depending upon the catchment, the type of sludge to be processed and the preferred final disposal route, therefore it is imperative that upfront testing is undertaken.

Aqua Enviro have operated labaortory scale trials on the treated feedstocks to provide process performance data to allow a full economica appraisal of proposed schemes.

Northumbrian Water's GBP 28 million Bran Sands CAMBI plant

‘The advanced digestion trials undertaken by Aqua Enviro were invaluable in helping to determine the preferred treatment process for the upgrade of the Bran Sands Regional Sludge Treatment Centre and in highlighting the understanding of the key design aspects’

Mike Rewcastle, Sludge Strategy Manager Northumbrian Water Limited

Aqua Enviro have undertaken pilot scale thermal hydrolysis for a wide range of organisations including Nortumbrian Water Limited, Anglian Water, Welsh Water, Black & Veatch, AECOM, Veolia, Cambi.

Click here for further information on Aqua Enviro's anaerobic digestion trials