The second major installation of a new multi stage digestion process is at Bromborough WWTP for United Utilities: it uses Enzymic hydrolysis pre-treatment prior to existing anaerobic digestion

United Utilities have installed a new multi stage digestion process at Bromborough WWTP. This is the second major installation of this technology using Enzymic hydrolysis pre-treatment prior to existing anaerobic digestion. The plant provides increased levels of pathogen reduction and replaces the need for secondary digestion at this site.

In addition the process confers additional process benefits, which include increases gas production and volatile matter destruction.

Since commissioning gas production levels have increased by about 25% from 4500 m3/d to 5500 m3/d.

The plant is designed to treat a maximum sludge throughput of 375 m3/d or 23 TDS per day but will currently operate a lower loading of 270 m3/d 16.5 TDS per day.

The plant has been constructed by Monsal in conjunction with the main framework contractor KMI.

The plant has been fully operational since January 2004.

Monsal are the development partner for United Utilities and the licensee for the hydrolysis technology.

Multi stage digestion is potentially one of the fastest growing technologies for larger centralised digestion facilities, providing a high quality sludge product whilst optimising VS destruction and renewable energy production.

The Enzymic hydrolysis reactor is designed to operate at 42C with a 2 day HRT prior to digestion.

The plug flow rector reactor configuration developed by Monsal and United Utilities is unique and ensures optimal conditions for pathogen reduction and hydrolysis reactions prior to anaerobic digestion.

Monsal are currently completing the detailed design for a larger multi stage digestion facility for the centralised sludge treatment centre at Crewe treating up to 12,000 TDS/annum.

The plant will be constructed by 2005.

Monsal are a specialist company providing environmental products, technology and research capability for the water and waste markets.

Monsal provide sustainable technology for anaerobic digestion, biogas and bioenergy, advanced digestion and specialist processes for the treatment of organic solids and wastewater.

Monsal services range from fundamental research capability through consultancy, design build and optimisation of water and waste projects in our specialist areas.

We work closely with our clients to deliver the most optimal solution.