Whanganui Wastewater Treatment Plant

Photo of two clarifiers at a wastewater treatment plan

By harnessing Cardno’s expertise in wastewater treatment, the new Whanganui Wastewater Treatment Plant has provided a sustainable and cost-effective solution to a range of issues facing the Whanganui District Council and the local community.

After opening in 2007, the old Whanganui Wastewater Treatment Plant experienced numerous issues. The Plant failed to comply with resource consent conditions on an ongoing basis, and during the summer of 2012-2013, significant odour events affected many Whanganui residents.  

Drawing from Cardno’s world leading expertise in wastewater treatment, our local team was engaged by Whanganui District Council in 2013 to design a new Wastewater Treatment Plant.  

Cardno specialists began the Whanganui project by undertaking a detailed review of all possible options for the new plant.  

We proposed a cost-effective, robust solution that made best use of existing assets for the new facility. Cardno’s designers focused on providing an effective wastewater treatment solution to ensure effluent consent compliance, as well as an odour control design that minimises the risk of future odour events 

Construction of the new plant began in September 2016 and was completed in March 2018. The plant processes around 28 million litres of wastewater each day – equivalent to approximately eleven Olympic-sized swimming pools. The ‘sludge’ resulting from the treatment process is dried, creating around 10 tonnes of pellets, which can be spread over land as fertiliser.