The largest infrastructure project undertaken in New Zealand for many years, and as a design build contract required total integration between the Beca design team and the contractors.
The former Prime Minister, Helen Clark, opened the new Mangere Wastewater Treatment Plant (WWTP) in 2003, hailing it as "Auckland's biggest infrastructural investment in a generation." This $450 million project involved an upgrade of the existing Mangere Wastewater Treatment Plant and the decommissioning of the oxidation ponds.
Beca was involved at an early stage in the project, with an ongoing role in early investigations and planning, and finally assisting with the masterplan for a major transformation of the old plant into a 21st century facility.
Watercare selected an international consortium, known as Manukau Wastewater Services, to deliver the upgrade through a design build contract, with Beca and its JV partner CH2M HILL as the designers. The old Mangere Wastewater Treatment Plant was progressively transformed into a state-of-the-art facility, while providing uninterrupted wastewater treatment service. Over five years the secondary and tertiary processes were replaced with new technology and other areas of the plant were either replaced or comprehensively upgraded. The new technology resulted in the treatment cycle for wastewater being reduced from 21 days to 13 hours.
The dismantling of the oxidation ponds was one of the most visual aspects of Project Manukau. Approximately 3.5 million cubic metres of sludge from the pond floors was dredged and disposed of, and more than 500 hectares of oxidation ponds and sludge lagoons and 13 kilometres of coastline were returned to a natural harbour environment. In 2003, this was the biggest coastal restoration effort ever attempted in New Zealand and acknowledged as a major environmental success.