Advanced digestion plans for Bran Sands: design and construct experiences
Rawlinson, D.1, Halliday, S.1, Garbutt, S.2 and Jobling, I. 2 , 1Northumbrian Water
(free)
In June 2007 Northumbrian Water Ltd (NWL) awarded a design and construct contract to Aker Solutions for a new Advanced Digestion Treatment Plant at the Bran Sands site on Teesside.
Following laboratory trials, advanced digestion via Thermal Hydrolysis was identified as the preferred treatment process for the upgrade of Bran Sands Regional Sludge Treatment Centre (RSTC). The plant will treat indigenous sludges generated on-site and imported sludge from around the Northumbrian Water region.
The plant has been designed for a maximum throughput of 40,000 tds/ annum and will generate up to 4.7 MW of electrical power for use on site at Bran Sands whilst at the same time producing a Class A biosolid product. Overall, this will reduce the whole Bran Sands site electricity usage at by up to 50 percent.
The modification to the drying plant at Bran Sands RSTC utilises existing liquid sludge storage facilities and dewatering facilities for raw indigenous sludges and for the final digested sludge product.
The new Advanced Digestion Facility consists of a twin cake reception facility and associated cake blending system, a two stream Thermal Hydrolysis Process (THP), three new digesters, two gas storage units, four gas engines and waste heat recovery units plus two package boilers and associated water treatment facilities.
A new cake storage facility will also allow 7 days storage of digested cake.
The project is nearing completion with functional testing now completed. Process Commissioning is due to commence in July 2009.
The proposed paper will describe the outline design approach and details of the process design used by Aker Solutions, lessons learnt by all parties through the design and construction process and provide early plant process performance results from the operation of the new Advanced Digestion plant.
