At first, it looked like a pond dewatering job.
A storage pond in Whangārei was holding up civil works because the water couldn’t simply be discharged. Testing showed it contained dissolved zinc contamination – a heavy metal that standard sediment control doesn’t remove.
Hansen Drainage & Earthworks Ltd
Located at Northport Boat Yard, the storage pond held about 60,000L of contaminated water – with dissolved zinc the main contaminant of concern. It needed to be dewatered and treated before civil works on adjacent land could proceed.
Because the treated water was going into the stormwater network and nearby harbour, the discharge solution had to be carefully controlled.
Have a water treatment job on the horizon? Get in touch with us today.
Aerial view of the Northport Boat Yard site – showing the storage pond needing treatment
The zinc, likely from sacrificial boat anodes, was dissolved in the water. That meant settling tanks or basic sediment removal wouldn’t be enough before discharge.
The job needed a more practical treatment solution.
Vessels configured for dissolved heavy metal treatment at the Northport Boat Yard site
Prime built a temporary water polishing setup tailored to the application. At the centre of it were several vessels – configured specifically to treat dissolved heavy metals before discharge.
This method was chosen because settlement could only deal with solids. The zinc remained in the water, so treatment had to happen as the water moved through selected media.
Each vessel was loaded with media specifically formulated for dissolved zinc removal. A support layer helped spread the flow and protect the underdrain.
A vessel full of a special product, designed to remove dissolved zinc
The vessels were run in parallel so more water could be treated at once – without bottlenecks slowing the job down.
Prime worked with a specialist supplier to find the right material composition to treat the zinc. The vessels then provided the pressure, containment and flow path needed to make that media work in a temporary site setup.
This wasn’t a standard hire setup. Prime took a treatment approach more often seen in permanent plants and made it practical for a civil project that needed water moved and treated at the same time.
Find out about Prime’s water treatment solutions and support.
The treated water was discharged safely, allowing civil works to proceed while reducing environmental risk to nearby waterways.
For Hansen Drainage & Earthworks Ltd, the value was practical – a discharge problem that standard sediment control couldn’t address now had a workable site solution. Civil works could proceed, with the water treated before release to the stormwater network and nearby harbour.
The project showed where specialist hire support matters most. It’s not just about supplying a pump but understanding why the usual treatment path doesn’t work – then configuring a temporary setup around the contaminant, flow rate and discharge risk.
Complete treatment setup - with pump and vessels to treat pond water before discharge.
Get in touch with Prime to discuss your water treatment needs.