When Waste Management purchased Tirohia Landfill in the Waikato three years ago, 70% of the methane gas produced by decomposing waste was released into the atmosphere.

Methane is one of the most potent greenhouse gases in Earth’s atmosphere and contributes significantly to climate change.

So we are very proud that today, thanks to our investment and expertise, 90% of all methane gas at Tirohia is captured and destroyed. The site now has additional capacity to convert more gas into energy to feed into the national grid.

It means we are making a huge reduction in carbon emissions. For those with some knowledge of Unique Emissions Factors, Tirohia’s emissions dropped from 0.7248 tCO2e/t (tonnes of carbon dioxide equivalent) in 2018 to 0.119 tCO2e/t last year.

Waste Management sustainability manager Adam Weller says this is a significant and powerful reduction, and we should celebrate our team’s success and commitment to reducing carbon emissions through best practice.

In the past year, the Waste Management team at Tirohia has:

- Added extra gas collection pipes into the landfill, and improved existing pipes to capture methane

- Introduced a larger flare for better destruction of residual methane and also installed additional blowers and a gas conditioning plant which removes all the moisture out of the gas and by doing so increases the engine oil life substantially

- Installed a new flow metre to better measure and record methane collection

It all adds up to a massive improvement, which now puts Tirohia on equal footing with Redvale (in Dairy Flat, Auckland) and Kate Valley (Canterbury) landfill & energy parks – which are widely held to be among the best modern, engineered landfills in the southern hemisphere.

Aerial view of the Tirohia Landfill