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Northland Waste manages around 20,000 tonnes of waste in Rodney each week. Chief executive Ray Lambert sees the new Re:Sort station as a commitment to Warkworth and says the success of the project was thanks to making sure all contractors were local. “The advantage of having local subbies is that they know each other and work well together as a team,” he says.
Good neighbours
Ray credits the Warkworth office of engineering firm LDE with preventing the new site from being the subject of a legal battle in the Environment Court.
LDE redesigned the site in response to mediation with neighbours. It now features “bunds” or small hills planted with native trees by McNaught Nurseries, which will effectively hide the transfer station within bush.
In response to feedback, the shed was also moved to the back of the site to minimise noise disruption, and a new fence was built for an immediate neighbour.
Another one of LDE’s design innovations is a “green water treatment” feature. Two 70-metre grassed swales divert
run-off water from the open yard and effectively filter any contaminants before they reach a subsoil drain.
LDE’s Aaron Holland says the swales can accommodate up to 500mm of heavy rainfall before water will begin to overflow into a drain. There is also a “rain garden” near the weighbridge which filters stormwater from the access way through four different layers of soil.
With these innovations, and a newly sealed road and concreted site, Ray Lambert believes the community is better off.
“We respected the neighbours’ desire for a better outcome, and I think the whole project is better for it. I believe there are now fewer impacts on the community here than before we built a transfer station,” he says.
Concreting under pressure
For Atlas Concrete’s Warkworth branch, the new transfer station is the largest project it has done since it established a local depot three years ago.
The Atlas team poured 150 cubic metres of concrete in a day, twice a week. For each section, the team had to prepare with aggregate, mesh and boxing, as it went along.
At 15 centimetres thick, the concrete surface had to be sturdy enough to withstand the constant pressure of truck and trailers moving about each day.
It is now rated to 30 megapascals, which is the equivalent of 300 kilograms of pressure per square centimetre.All told, Atlas poured 1750 cubic metres of concrete for the project, used 3700 tonnes of aggregate and 1200 sheets of high-tensile mesh.
Manager Troy Rolfe-Vyson says it was just one job among many, with all five of his trucks “flat out” since lockdown restrictions eased for construction.
He says it helped that there were well organised tradies working on the project. One was Jamie Hardwick, of Prime
Earthworks, who was in charge of preparing the final touches on 8000 square metres of surface, before the critical moment of the concrete pour.
A master of the trade, Jamie says his precision skills simply come down to having a “good eye”. He reckons laser instruments are prone to mistakes and haven’t yet caught up to the “bucket and string” method. A concrete surface might need a subtle gradient across hundreds of metres to facilitate drainage, with a difference of only 80 millimetres at either end. This requires precision. Jamie says all of his work is “word-of-mouth” and this project was no different. He was working for another company on the concrete slab inside the sorting station when Northland Waste needed someone for the outdoor surface, and Jamie “put his hand up”.
No time or resource wasted
Andrew Boyd, of Coresteel Rodney, is confident that the large waste sorting station was itself “99 per cent” waste free, with all offcuts being recycled into reusable material.
“The remaining one per cent would be the tradesmen’s lunch wraps generated during installation,” he jokes.
Coresteel did a bespoke design for the transfer station, with the height of cranes and trucks in mind.
The building is around 750 square metres with a height of 12.5 metres. But, most importantly, it also has 7.5 metre high doors.
Andrew says this is so that large rubbish trucks won’t hit the top if they accidentally forget to lower their tipper bucket.
The concrete floor has reinforcing steel fibres and was done in a single pour so that there are no joins or cracks where a grader bucket might catch and damage it. The floor has been designed with a slope so that liquid run off is caught into a sewer drain to be treated and not accidentally flushed into stormwater drains.
With an evolving design, Northland Waste benefited from local electrician John Lepper, of Mahurangi Electrical, being on call. John was responsible for the design and installation of power for the sorting station, weighbridge and water treatment facilities. He worked with Vector to replace power lines with underground cabling and the building of a new transformer.
John says he was particularly proud to be a part of the project because Northland Waste has been helping him to reduce his construction waste by sorting it into streams.
“It’s good to be part of something that helps us out environmentally. That’s something we value highly,” he says.
Northland Waste estimates that, thanks to the new facility, it will be able to divert around half of the construction waste it receives.
