Aldermaston STW – Wastewater Asset Assurance Programme

Inlet pumping. New duty/standby variable speed inlet pumps were installed within the existing inlet pumping station wet well, sized to support the required duty flowrate and improve the resilience of the inlet transfer process.

Raised inlet works and balancing tank. Woodhams carried out the mechanical works associated with the new raised inlet works arrangement, including process pipework connections, manufacture of the new balancing tank, mechanical interfaces, hydrobrake installation, flow control connections and pipework integration with the downstream treatment process. The balancing tank arrangement included storm separation and flow control functionality, with washout and drain provision for maintenance.

Storm tank and storm return pumping. Mechanical works covered pipework connections from the storm tank overflow to the downstream chamber, process pipework between the storm tank and the existing storm land treatment area, and the interfaces allowing storm flows to be managed through the upgraded process. The new storm return pumping arrangement included duty/standby progressive cavity pumps and discharge pipework back to the raised inlet works, returning storm flows at a controlled rate so the storm tank could be emptied following storm events.

Primary settlement tank. The new PST was fitted with mechanical and process equipment including a fixed bridge, manual scum removal system, manual desludging system and auto-desludging system, together with the associated pump installation, valves, pipework and mechanical connections to the existing sludge holding tank. The auto-desludge system used a duty progressive cavity pump transferring sludge from the PST to the existing holding tank, with manual desludge arrangements for routine and emergency use, isolation valves and a Bauer connection for temporary desludging equipment.

Return liquors and sludge pipework. Woodhams delivered the mechanical works for the new Return Liquors Pumping Station, including duty/standby submersible pumps, rising main pipework and connections back to the new PST inlet chamber, designed to return flows at a controlled rate while preventing excessive pump starts. The scope also included modifications to the existing sludge holding tank pipework and diversion of the existing humus tank desludge pipeline to the new return liquors pumping station — works that required careful sequencing to avoid simultaneous desludge flows reaching the return liquors system.

Process pipework and mechanical interfaces. Woodhams coordinated and installed the full range of connections between new and existing assets: inlet pump discharge and process connections, balancing tank forward flow and storm separation pipework, storm tank overflow and discharge pipework, storm return pumping discharge, PST desludge and scum removal pipework, return liquors rising main, sludge holding tank modifications, humus tank desludge diversion, and connections into existing below-ground and above-ground process systems.