- Case Studies
As part of an on-going development programme, Thames Water appointed Tamesis (a Joint Venture of Imtech Process and Laing O’Rourke), to co-ordinate the project at Crossness Sewage Treatment Works
The aim was to expand the sewage treatment works (STW) in anticipation of increased population growth and to treat the sewage waste to a higher standard, whilst also preventing sewage overflow into the River Thames. Crossness STW is one of the largest facilities in Europe, serving a population of approximately 1.8 million people in east London.
Aware of Edina’s involvement with many sewage treatment projects, Tamesis invited Edina to submit proposals for the sewage gas utilisation through Combined Heat and Power (CHP) production. Following the acceptance of Edina’s proposal, a full-time Project Manager was appointed to oversee and co-ordinate the scope of works.
The project involved close liaison with other contractors on site, full HAZOP (Hazard and Operability) participation and careful consideration to concurrent site operations.
With an output of 2MWe each, the MWM manufactured TCG 2020 V20 gas engine was selected due to its high electrical efficiency and three orders were placed totalling a combined 6MWe output. The project included a fully inclusive maintenance contract, which provided the client with the lowest lifecycle operating cost.
The thermal hydrolysis plant will burn the highly combustible sewage sludge created after waste water treatment to 160 degrees Celsius, to produce 50 per cent more biogas prior to the anaerobic digestion (AD) process. The biogas will be combusted within the CHP plant to generate electricity and heat used on site with excess sold to the electricity grid.
When combined with the adjacent Beckton STW installation, the 12MWe CHP plants will produce enough electricity to power 24,000 homes. The engine jacket water heat will be used for digester heating with the exhaust fed to waste heat boilers for steam production to assist the advanced digestion process. These gensets habitually operate at an overall efficiency in excess of 85 per cent with uptime of >92 per cent.
The gensets were containerised within acoustic attenuated enclosures at Edina’s manufacturing facility based in Lisburn, Northern Ireland and included all ancillary equipment which was assembled and tested at Edina’s factory, reducing site installation time and project cost.
This makes possible a “plug and play” unit with full adherence to all UK, European and Ireland Regulations. The experience and ability of Edina to containerise the 2MWe gen-set, sets it apart from its competitors and was a key factor in Tamesis’ choice.
Tamesis Joint Venture
3 x 2MWe TCG 2020 V20