During the week of 21 July, Waikato District Council will be using a specialised unit to carry out water flushing in Huntly.
Council will be using the NO-DES (Neutral Output Discharge Elimination System) unit, operated by Detection Services, to flush and remove mineral deposits from the water pipes.
“Huntly gets its water from the Waikato river,” says Waters Manager Keith Martin. “The water intake is below the Mangawara stream in Taupiri and this stream has high levels of manganese, which is a naturally occurring mineral.
“Dissolved minerals build up in the pipes where they eventually drop off and are swept up by the flow of the water. This can sometimes cause the water to look discoloured. Even though the water is still safe to drink, we know that the water colour is off-putting for people.”
For this reason, Council has been undertaking a programme of work to improve the water supply in Huntly, including upgrading water lines and flushing the pipes more regularly, which has resulted in less incidents of brown water.
As part of this programme of work, Council has engaged Detection Services and will be using their specialist unit to remove accumulated mineral deposits in the network.
The unit uses a reverse flow to scrub the sediment build-up off the pipes and then filters it out.
“This technology connects hydrant-to-hydrant, using reverse-flow flushing to remove iron and manganese deposits from water lines. The process filters out debris with minimal water loss and will target key areas in Huntly, to improve water quality across the network.”
While the work won’t require the water to be shut off, there may be some disruption to traffic during the week. Be on the look out for the NO-DES truck on a street near you, says Martin.
“People may see work being carried out on the side of some roads, and there may be a few areas where the NO-DES hose will have to cross the road to reach hydrants,” says Martin. “We will have signage and traffic management in place in those areas.”
Detection Services/NO-DES staff have significant experience in carrying out this work. The unit has been used by a number of councils around New Zealand and Australia.
How does it work?
The NO-DES (Neutral Output Discharge Elimination System) unit works by creating a temporary loop in the reticulation system. It has a large variable speed drive pump which circulates water through the loop at well above the self-cleansing velocity of the water main. The increased velocity lifts the sediment off the pipe walls. As it passes through the chamber filtration system, the sediment is removed as it passes through the 24-chamber filtration system.
Will the water be turned off while this work is happening?
No. Huntly’s water supply will not be affected.
What other things is Council doing to improve the water in Huntly?
In the future, Council plans to upgrade the water treatment plant so that it can be better at dealing with the manganese deposits.
