At a time when territorial authorities were primarily responsible for managing solid waste, Redvale was the first privately owned landfill in New Zealand. It was developed to serve the burgeoning population of Auckland and was then quickly the largest landfill in the country at 20 million m³. It was also the most modern landfill – ushering into New Zealand a new era of highly engineered solid waste management facilities.
From inception, Tonkin + Taylor worked with Waste Management International Inc’s team of engineers to select the site and to progress it from concept designs to consenting. Resource consents were granted in 1992, and we moved immediately into detailed design and construction of the site access and facilities and the first stage of the landfill.
Over the years, we have partnered with the owner, Waste Management NZ, to develop 17 landfill cells at Redvale. Various ancillary projects have also been undertaken, including the site drainage and stormwater treatment system comprising six stormwater treatment ponds.
Redvale Landfill is in a geological formation ideally suited to waste disposal. The thick layers of very low permeability mudstone and limestone beneath the site make it very difficult for contaminants to leak out of the landfill.
The geology, however, is also highly challenging, and most projects at Redvale require significant input from our engineering geologists and geotechnical engineers. Key among these are the temporary slopes and sides of the landfill pit, some of which are up to 50 m high. In addition, six large temporary and permanent stockpiles have been developed on and around the site.
The landfill includes a gas-to-energy plant, flares, and a leachate evaporator primarily developed by the owner. We have also provided expert support to the required air discharge consents.