Thames Water

marine-and-rivers-thames-water-beckton

Facts and figures

  • The Thames Gateway Water Treatment Plant provides a new water resource to maintain the water supply-demand balance within London
  • 24-month programme to construct and commission the plant
  • The joint venture offered the client Interserve's water industry project management and construction experience combined with Acciona Agua's track record in designing and operating reverse osmosis desalination plants

Gateway treatment plant

Interserve's joint venture with Acciona constructed a 150,000-m3/day reverse osmosis desalination facility to treat brackish water abstracted from the Thames estuary.

marine-and-rivers-hrh-the-duke-of-edinburgh-opens-beckton-thames-water-desalination-plantOpened by HRH The Duke of Edinburgh, the unique desalination plant located on the north shore of the River Thames at Beckton, takes water from the tidal Thames and removes the salt to produce enough drinking water to supply about one million people.

The four-stage design and construction contract included; project design development; planning application preparation; environmental impact assessment; cost development; programme development for construction, procurement, erection and commissioning; operation of the pilot plant; and site clearance, demolition and enabling works.

To maintain the supply-demand balance within London, the tidal stretch of the river provides a practically limitless supply of water that can be harnessed without further stressing the environment.

The tidal and seasonal variability of the raw water in terms of salinity, temperature and concentrations of dissolved and particulate organic and inorganic matter presented unique treatment challenges. A pilot plant was commissioned at the proposed site and was operated for an 18-month period to test candidate pre-treatment technologies and to define the raw water design envelope and full-scale plant process design criteria.

The process design included raw water intake via screens, raw water storage, mixing and equalisation, coagulation, flocculation, lamella clarification, pressure sand filtration, ultrafiltration (UF), a four-stage reverse osmosis (RO) system and post-treatment including re-mineralisation, disinfection and plumbosolvency control.

Awards

  • The plant won the 2011 Global Water Award as the Best Desalination Plant of the Year
  • Winner of the London and South East Constructing Excellence Awards 2010 in the Innovation Category
  • Most Sustainable Project at the Global Water Intelligence (GWI) Awards 2009

Sustainability in action

A number of design innovations were employed to minimise energy consumption of the plant including:

  • The raw water storage and equalisation tank allows for raw water abstraction to be constrained to three hours per tidal cycle on an ebb tide approaching low tide conditions. Thus the raw water salt concentration and power consumption is minimised.
  • Included Pelton turbines to recover energy from the reject stream
  • Using variable speed drives on the four stages of reverse osmosis feed pumps reduces energy wastage through permeate throttling
  • The plant's energy demand is met by renewable energy
  • Innovative electrical engineering: Using higher voltage transmission of 33 kV as opposed to 11 kV and water cooled switch gear as opposed to air cooling and intelligent assemblies, helps monitor electrical energy use and efficiency.

The treated water quality specification, developed to ensure that the treated water:

  • Is compliant with UK legislation and Thames Water internal standards
  • Is non-aggressive to the distribution network (slightly scale forming)
  • Minimises the impact on domestic and commercial customers