Delayed New Zealand Wastewater Project Progressing

May 24, 2007

The end is in sight for a $13 million comprehensive wastewater upgrade in Palmerston North, New Zealand, which began in 2003 and will not be operational until November 2007.

Work began late last year on the final stage, the $9.2 million phosphorus and sludge dewatering plant. Council contractor HEB Smithbridge is currently building a clarifier, which will remove phosphorus from the wastewater to further purify it before it is discharged into the river.

The upgrade is a reflection of the City Council’s commitment to discharging only water of the highest quality back into the Manawatu River, and has been designed to meet city growth over the next 25 years.

Project Manager, David Cotton, explains that the plant is a key process in taking raw sewerage and treating it effectively to meet stringent Horizons Regional Council standards.

Wastewater from the aerated lagoon will enter the clarifier and, when the phosphorus is removed, the treated water will be pumped into the UV disinfection system for further purification.

The sludge dewatering plant removes the water from the sludge accumulating in the clarifier and dries it prior to disposal.

This second and final stage of the wastewater treatment plant upgrade is a further treatment process (tertiary) to improve the quality of treated wastewater and is in addition to the primary and secondary treatment processes already in place. The quality of wastewater produced after the three stages of treatment (primary, secondary and tertiary) will help meet Horizons’ contact recreation (swimming) standards for the river.

City Council Project Manager, David Cotton, was recruited in London last year to handle the final stage. David is a Civil Engineer and managed a number of major projects throughout the United Kingdom before relocating to Palmerston North in August 2006.

He says the upgrade is technically interesting because of its multi-disciplined content encompassing civil, structural, mechanical, electrical and process engineering.

Source: Palmerston North City Council

Image by Burnham RNG, courtesy twentytwo & brand.