Sutton Bingham Water Treatment Plant Upgrade, Yeovil, UK

Sutton Bingham Water Treatment Works serves the Yeovil area. It is supplied by a raw water reservoir in which large blooms of blue green algae occur. The algae produces geosmin and MIB both of which can adversely affect taste and odour.

The existing treatment, which comprised clarification by dissolved air filtration (DAF) and rapid gravity filtration through granular activated carbon, was unable to consistently meet Wessex Water’s treated water standard of 4 ng/l for geosmin and MIB and lacked a capability to remove manganese. Additional issues, which Wessex Water required Sweco to resolve, included the inability of the works to ramp up from its typical flow of 8 to 10 Ml/d to its design maximum of 18 Ml/d and scaling due to the hard water.

Before the advanced oxidation treatment was removed from the project scope, Sweco completed the outline design of the treatment process using ozone generation/dosing, liquid oxygen storage/dosing and hydrogen peroxide storage/dosing upstream of the granulated activated carbon (GAC) stage. This process solution is rarely seen in the UK and was the first such design undertaken by Sweco.

The final approved solution that was constructed comprised:

• An interstage pumping station
• Manganese contactors (pressure vessels)
• A new stage of GAC comprising an open tank system complete with eductors and backwash pumps
• New washwater pumps and washwater recovery facilities
• pH correction via alkali dosing
• Upgraded existing chemical dosing system
• Configuration to accept a possible future advanced oxidation process
• Associated instrumentation and controls for the above plant

Sweco provided the economic analysis used by Wessex Water to assess / approve the final solution. The increased GAC volume and subsequent regeneration costs were offset by the removal of the advanced oxidation treatment process. We also developed 3D CAD models for rapid live visualisation and modification during client/contractor constructability reviews.

Our staff were co-located in Wessex Water’s Bath office and worked in collaboration with the contractors and supply chain throughout the design and construction period.