Acting as designer to Morgan Sindall for the Dŵr Cymru Welsh Water Framework, Sweco was commissioned to design the refurbishment works at Langdon Road Sewage Pumping Station. The 10m diameter, 20m deep pumping station wet well had air entrainment issues that caused the pumps to frequently fail and spill sewage into Swansea Bay.
Client: Dwr Cymru Welsh Water
Location: South Wales
Contract Value: £4.7m
The services provided by Sweco included:
For 10 years, Swansea’s Terminal Pumping Station, Langdon Road did not achieve its pass forward flow rate due to the presence of air-entrainment within the wet well, which led to pumps breaking in the wet well. Sweco and Morgan Sindall were tasked with modifying the wet well and pump arrangement to reduce the maintenance requirements.
We engaged BHR Group to build a physical model of the existing wet well and investigate measures to reduce the air-entrainment. The solution was to modify the existing sump, provide a new benching arrangement and reposition the pumps. In order to gain access for both the construction works and future maintenance, a new cover slab was also required.
The new benching, pipe work and cover slab design were all related to the existing arrangement. Consequently, the exact location and dimensions of the existing assets in the wet well were critical to the design. The challenges faced were;
Any survey method involving man entry into the wet well was therefore discounted. Using innovative technology, Sweco undertook a 3D dimensional “pointcloud” laser survey, which avoided the need for man entry into the wet well. This produced an accurate 3D model of the wet well that formed the basis of the final design. The 3D survey also allowed us to design pre-cast elements for the cover slab and benching - thus minimising the health & safety risks associated with man-entry during construction. We also used the 3D survey to maximise the use of standard fittings and establish a construction sequence that provided both time and cost savings.