Treated Wastewater Irrigates Pauanui

TCDC Consultants URS design disposal system throughout township.



Engineers are putting the final touches on the design of an “extremely complex” and precise underground irrigation system that will re-use treated wastewater for a greener Pauanui.



The council is limited to a maximum disposal of 5,400 cu m per day of the highly treated wastewater from the new plant and aims to beneficially re-use as much of this as possible on Pauanui’s green spaces.



“People won’t ‘see’ anything with this new system, since it will all be underground,” explained Project Manager Gordon Reynolds. “However some trees will need to be removed along the main pipeline route. On the positive side we will remove the ugly disposal systems currently in Vista Paku, and Pauanui will be greener.”



Treated water will be disposed of via pipeline feeders under the soil at three areas; Kennedy Park - for which construction of the pipelines is expected to begin at the start of March next year- parts of Vista Paku – where construction will start in late March to April - and a strip along the Pauanui Airfield in June.



Resource consent allows for only 5mm per day to be irrigated over a maximum area of 60 cu m on the airfield, which is a drip-feed amount. More investigation is needed into the potential effects on aquifers if this amount is increased, however the irrigation system is being ‘future-proof’ designed so that the entire airfield could be irrigated to dispose of much larger volumes in decades to come.



“As the communities of Pauanui and Tairua grow, there’ll be a greater need to get rid of larger volumes of wastewater,” said Mr Reynolds. “We can look into further water being re-used over more of the airfield and other parts of Pauanui. Any increase above 5,400 cu m per day will be subject to a future resource consent process,” he added.



The new wastewater treatment plant at Pauanui will need to dispose of double the amount of wastewater produced by the old plant. In current off-peak times the rate of wastewater produced is 900 – 1100 cu m per day but this rises to 3,000 cu m per day in the peak summer period and even higher with heavy rainfall during Christmas.



The Tairua-Pauanui Community Board will be involved in landscaping issues associated with the new disposal system. “All efforts will be made to retain as many trees as possible, however some will need to go,” said Mr Reynolds.