Abergeldie upgraded Dora Creek WWTW, the capacity of the pre-existing plant was doubled by construction of new inlet works, septage receiver facility, soil bed filter; switch room, two clarifiers and pump stations. Modifications were also made to two bioreactors. Associated works included mechanical and electrical works, pipework, pumps, control systems, testing and commissioning. Civil works included new access roads, landscaping and demolition of existing inlet structures.
The upgrade required conversion of a semi batch decant process, still in use, to a continuous activated sludge process with no license breaches. This involved modifying existing tanks, requiring detailed planning and design to ensure sections of the plant could be bypassed for long durations to allow refit and commissioning of the new sections before bringing them on line. Close cooperation between Abergeldie’s in-house design team, commissioning teams and the utility owner developed a detailed and effective system of temporary bypasses and maintained continued operation of the plant.