Westland finishes wastewater pipeline project

Westland resident director Shiqing Jian said a significant proportion of work was undertaken by locally based contractors, ensuring a proportion of the budget was spent in the local community.

Westland general manager of supply and environment, Mark Lockington, said local contractors WestRoads laid 4.3km of underground pipe from the factory to 100m south of Westland District Council’s oxidation ponds ending at a de-aeration chamber behind beachside dunes.

Engineering firm McConnell Dowell were contracted to tunnel and lay an under-seabed pipeline from the de-aeration chamber to a point 800m out to sea. A team of divers was deployed by McConnell Dowell to attach a diffuser unit to the underwater pipeline where it emerged from the seabed.

Covid-19 restrictions caused slight delays to the completion of the project, originally scheduled for March 2021, with final completion work limited to appropriate weather and ocean conditions providing safe working conditions and procedures.

Following the completion of the project, trial runs of water and then highly treated wastewater were discharged through the ocean outfall pipe, and operational procedures were finalized, with the pipeline coming into use from May 10.

Jian said the pipeline has been designed to ensure minimal visible disruption to the local landscape and allows for Westland District Council to use the pipeline if needed as part of any future upgrades to council’s sewage treatment outfall.