Anglian Water has led the UK Water industry in successfully developing and delivering four Advanced Digestion plants in AMP4. These plants at Kings Lynn, Cotton valley, Whitlingham, and Great Billing, were designed to process 100,000 tDS/y of raw sludge (approx 60% of all sludge produced across Anglian Water), to produce enhanced quality sludge cake, deliver lowest sustainable cost of service and generate more than 40GWh of renewable power.
This paper examines the delivery of the Great Billing project. The Great Billing Advanced Digestion plant is the largest plant of its type in the UK, treating up to 38,500 tDS/year. Following planning approval this plant was safely constructed in a record time of 13 months through a successful collaborative arrangement with Anglian Water Special Projects.
The project combines several innovative features, including importing raw sludge cake from the large satellite sites of Flag Fen (Peterborough) and Broadholme, sludge cake blending and thickening to 8% DS, largest enhanced enzymic hydrolysis plant and high efficiency CHP for maximum renewable power generation and producing hot water and steam for process heating.
The plant has been the subject of an extended commissioning period. We have worked closely as an integrated team with local operations to optimise plant performance. Industry leading performance levels have been achieved including specific renewable power efficiency of approximately 0.9 MWh/tDS. Fully power self sufficient waste water service has been achieved with renewable power generation of 60-75 MWh/day compared to a power demand for waste water and sludge treatment of approximately 40 MWh/day. The team will continue to support further optimisation of plant performance through an extended two year Sludge OPEX Optimisation Programme (SOOP).
Anglian Water has reviewed best practise, captured lessons learnt and plan to deliver an additional five full scale plants before 2015.
Keywords: Advanced Digestion, Monsal Enhanced Enzymic Hydrolysis (EEH), High Efficiency CHP, enhanced sludge quality, power self sufficient operation, operational savings, sustainability
Anglian Water has led the UK Water industry in successfully developing and delivering four full-scale plants in AMP4. These plants at Kings Lynn, Cottonvalley, Whitlingham, and Great Billing, were designed to process 100,000 tDS/y of raw sludge (approx 60% of all sludge produced across Anglian Water), to produce enhanced quality sludge cake, and deliver lowest sustainable cost of service with targeted operational savings of over £6M/yr and generate more than 40GWh of renewable power.
Both Enhanced Enzymic Hydrolysis and Thermal Hydrolysis plants have been delivered. This paper focuses on the latest advanced digestion plant to be completed at Great Billing and describes the delivery experience, and full-scale performance with respect to sludge load, solids destruction, energy balance, power generation, pathogen destruction and treated sludge dewatering.
The Great Billing plant has been the subject of an extended performance optimisation period working closely with the local operational team to ensure full integration with existing assets and management of interdependencies with satellite sites. The plant has been successfully delivered and optimised to give industry leading performance and efficiency benchmarks. Volatile Solids (VS) destruction levels of approximately 50% have been achieved with higher gas yields than conventional AD plants and renewable power generation efficiency levels in the range of 0.8-1 MWh/tDS treated. Enhanced quality sludge and power self sufficient wastewater service has been achieved.