DCWW – Aberbaidan Primary Settlement Tank

As part of a scheme to design and build a new Primary Settlement Tank (PST), OCU were contracted by Dwr Cymru Welsh Water (DCWW) as part of our Pressurised Pipework Framework Contract to carry out the design and installation of a new 10m Diameter Primary Settlement Tank (PST) with all associated civil, mechanical, electrical and instrumentation works and construction of site access roads.

The works comprised the construction of the PST with a half bridge mechanical scraper along with sludge pumping systems and full control and telemetry installation.

Aberbaiden WwTW receives its flow from 2 number incoming lines from the North, Southwest and West of the works and a foul line from the Southeast of the works. Both flows meet in a chamber before entering the works to receive treatment. Treated effluent is then discharged into to the River Usk.

The aim of the scheme was to increase Primary Treatment Capacity to allow for the works to cope with increasing incoming flow levels to the works.  To facilitate this, the following scope of works was commissioned.

Scope of Works

OCU was responsible for all of the following activities on the project:

• Temporary over pumping from works inlet to existing PST and other over pumping required to facilitate investigation, construction works and commissioning
• Area of hard standing to be created for welfare accommodation and material / plant storage. Existing vegetation and bunded area to be stripped and stockpiled and new bunded area to be located to the west adjacent to proposed new boundary fence line
• Existing access and surrounding land to be reinstated as existing following completion of the works
• Temporary shoring to be placed in excavations where access is required for underground pipework
• Temporary shoring to be placed in excavations where access is required for PST, chamber manhole construction and at all other locations requiring formwork as identified by the contractor
• Formwork to be erected for slab construction and for all other locations requiring formwork as identified by the Contractor
• Scaffolding or an equivalent proposed method of safe access to be utilised for working at height
• Construction of the PST and all associated MEICA equipment including commissioning and handover of the works