Waste Transformation Limited (WTL), a company with Ōtaki connections and Raukawa ki te Tonga AHC as a cornerstone shareholder, has developed a global leading waste diversion system using a proven technology that turns waste wood into valuable by-products.

Over the past five years, WTL has moved from proof of concept to full commercialisation with a new plant capable of processing 200 tonnes of waste timber a month and producing, when fully operational, up to 80 tonnes of commercial charcoal. The company’s operations are currently based at Timaru District Council’s Redruth Resource Recovery Park, where its new plant is diverting all recoverable untreated waste timber from the landfill.

WTL is largely Māori-owned, with Ōtaki-based Raukawa ki te Tonga AHC having a cornerstone shareholding of about 38 percent. Other shareholders are Spectionz, predominantly Ngāti Hine and close associates with 25 percent; and Kilnz Bio Energy and close associates, predominantly Ngāti Raukawa, holding 37 percent.

Raukawa ki te Tonga AHC was established as the commercial organisation to manage the settlement assets and investments of Raukawa ki te Tonga Trust.

Jack Morris, Raukawa ki te Tonga AHC’s chief executive, says WTL is an ideal investment for his company.

“We are a longer-term investor committed to socially responsible investing,” he says. “WTL ticks the environmental box, transforming waste to an environmentally friendly fuel source, creates employment in regional centres, is innovative and Māori-owned and managed.

“We also have good reason to believe that it will be a commercial success given that it addresses the need for territorial authorities to better manage their waste streams.”

The WTL technology has significant environmental benefits. The Ministry for the Environment estimates that each year about 400,000 tonnes of timber are consigned to the country’s landfills, constituting about 15 percent of the national waste stream. Waste wood is particularly challenging in that it’s bulky, difficult to compact and produces greenhouse gases (GHG) as it decomposes.

Landfills are a huge problem in that the land use is permanently lost from agricultural, housing or business use. It’s also expensive and becoming more so, given the cost of land and the associated engineering safeguards required to prevent toxic leachate from reaching groundwater or streams. Hence the need to minimise hazardous waste and encourage the re-use and repurposing of building site and demolition materials.

Charcoal, produced from waste wood, also has the potential to replace coal as an industrial fuel source. Compared with coal, charcoal has a higher energy value, zero sulphur oxides and lower nitrous oxide emissions. Charcoal is also smokeless.

WTL has taken a proven technology –pyrolysis – and built an economic unit that is scaled to New Zealand conditions and environmentally compliant. Overseas pyrolysis plants require huge waste volumes to be economic.

“There’s no other comparable plant in New Zealand,” says WTL chief executive Mike Henare. “What we’ve been able to do is to develop a unit that is economic and matches the waste disposal requirements of New Zealand’s regions. The plant is transportable, designed to go to the waste stream and not require the waste streams to be transported to a significantly larger centralised plant.

“This sized unit also provides better control, especially when dealing with problematic waste steams such as treated timber and tyres. While the proof of concept has been based around waste timber (excluding CCA-treated timber) the company has its sights on solutions for these other problematic waste streams.

“Our new kiln is fully automated, PLC and tablet-driven and meets the Australian Standard AS1375. There’s no New Zealand standard for this type of equipment.”

(PLC – a programmable logic controller – is an industrial computer control system that continuously monitors the state of input devices and makes decisions based on a custom program to control the state of output devices.)

The company’s technology development has been supported since inception by an independent science and technology panel. A Massey University study presented to the 2016 Chemeca Conference established that when taking all the greenhouse gas contributions into account, wood pyrolysis has about zero greenhouse gas emissions compared with about 1760 kgCO₂/tonne for clean-burning wood.

“The operation has been carefully developed with full consideration given to health and safety of the operation and equipment, and the processing is carried out under a consent with Environment Canterbury,” Mike says.