Better sewerage built for Kerikeri
In 2013, the Far North District Council’s community engagement programme called “Let’s Talk Crap” got residents talking about what they wanted for their sewerage.
Sixty per cent of the 650 submitters said they wanted more properties connected to the council’s sewerage scheme, rather than the ongoing use of septic tanks.
In 2015, formal consultation was run as part of the council’s Proposed Long Term Plan 20152025.
From this, the council got the mandate to extend the sewerage reticulation network in central Kerikeri, plus build a new wastewater treatment plant to increase treatment capacity.
“Many properties in central Kerikeri rely on on-site disposal systems – generally these are septic tanks and soakage fields,” says Mayor John Carter.
“These can pose a risk to the environment if they’re not maintained properly, or used in unsuitable soils,”Kerikeri has also outgrown its existing wastewater treatment plant, which is 28 years old.
Carter says the plant is running at capacity and failing to meet the discharge standards required by the discharge consent.
The first contract includes expanding the sewerage network in central Kerikeri by about 28km, allowing an extra 350 existing homes and businesses to connect to the scheme.
This contract was awarded to United Civil Construction this year, with physical work starting in June.
Privately owned and founded in 2006 by Andrew Campbell and Paul Mandeno, United Civil Construction has undertaken a wide range of significant civil projects including state highway reconstruction, local authority intersection upgrades, sewerage systems, water reticulation, bridge replacements and stormwater works.
It is also a key partner in a joint venture company, Maintenir, that holds the contract for the maintenance and heavy infrastructure at the Marsden Point Oil Refinery.
Having successfully completed a similar low-pressure sewerage scheme in Opua, Bay of Islands in 2012/13 that overcame a number of significant geological challenges to complete the project on time and on budget, United Civil Construction was ideally suited to undertake the Kerikeri wastewater project.
Greg Whitehorn, project manager for the Kerikeri Wastewater Reticulation Scheme, says the contract involves installing a network of wastewater pressure pipes that connect each of the 350 properties’ new private pump chambers to the new wastewater treatment plant.
In addition there are booster pump stations and a terminal pump station to be constructed. “There’s about 28km of pipe to be installed in total,” explains Greg.
“We have installed about 19km of pipeline so far and expect to complete the contract in March next year in terms of laying pipe and installing the pump chambers, with the booster pump stations completed by June.”
The pump chambers, measuring 800mm in diameter, are placed two metres deep in each of the properties connecting to the new scheme.
Once installed, the pump chambers are connected to the pressure pipeline that is being installed in the road.
The chambers will pump the sewage to the new treatment plant once it is built as part of a separate contract.
“We’re directional drilling most of the pipeline to reduce the impact to private properties, road users and pedestrians as much as possible,” says Greg.
“We’re about 70% of the way through the pipework installation and overall we’re sitting at about 65% of the way through the contract.”
He says there have been a number of geological challenges in that the Kerikeri area is volcanic with a lot of rock. In some cases it has not been possible to directional drill and trenches have had to be dug to lay pipe. The contract is tracking on time and on budget.
Once the treatment plant itself has been completed and commissioned, United Civil will return to each of the residents’ homes and decommission the old septic tanks.
The second part of the FNDC project is the building of a new wastewater treatment plant on a rural site 3km to the south-east of the town.
Council has bought the land for this project but has not yet awarded the construction contract.