24 January 2020
EnviroWaste boosts composting capacity to bite into food waste
With the final touches being applied to a purpose-built receivals building and engineered compost system trenches at EnviroWaste’s Hampton Downs facility, the company is set to boost its organic processing capacity to 20,000 tonnes per annum by 2020.
That’s a big leap from the 4,000 tonnes we processed in 2015, reflecting cross-industry uptake of sustainability initiatives to divert organics and recyclables from landfill, as well as council-led initiatives plotting a waste-free future.
What’s also good, is that demand for processed organic outputs – compost and liquid fertiliser – currently outstrips supply. Horticulturists and large-scale farming operations, among others, want compost and chemical-free fertilisers to replace nitrogen heavy soil additives.
For years now, EnviroWaste has collected green waste from company transfer stations in Auckland and Hamilton, and residential kerbside food waste and inedible food from commercial customers, processing it at our composting and vermiculture (worm farm) facility in Hampton Downs.
Our composting system uses German technology called GORE – a bunker system that creates a moist, oxygen-rich environment for microbes to convert waste to compost.
However, the latest capacity upgrade to our organics processing operation is designed specifically for odorous food waste. The new system sees trucks drive inside a receivals building with negative internal air pressure, designed to contain odours. Once unloaded, the organic matter is shredded inside the building and deposited in an engineered compost system bunker, where computer-controlled temperature and oxygenation accelerates degradation to the point that organic material is sufficiently stable for transfer to the GORE system.
The net result is a significant uptick in EnviroWaste’s organics processing capacity. There’s more to come, too, given the volume of organic material currently lost to landfill.
Each year in New Zealand 2.5 million tonnes of waste goes to landfill
That represents around four percent of the country’s total carbon emissions – most of which is from food and organic waste.
When it comes to food, we’re a nation of wasters. Each week we throw out around 13% of the food we buy, representing a $1.8 billion food waste problem. Granted, some discarded food ends up in a compost bin, but the lion’s share goes to landfill where it rots, releasing methane – a greenhouse gas – which harms the environment.
A waste audit undertaken by Tauranga City Council last year shows that two-thirds (66%) of kerbside waste had the potential to be recycled or composted. The biggest culprit was organic waste, with 48.5% of the rubbish being compostable.
Tauranga City Council’s planned roll-out of a rates-funded kerbside food scraps, recycling and rubbish service in 2021 can’t come soon enough. Further north, Auckland Council is also set to introduce a kerb-side food scraps collection following a successful trial introduced in Papakura in 2018 – a key component in Auckland Council's push to get the region waste free by 2040.
Piling into commercial food waste
While household food waste is easily managed through composting, in the commercial world, most waste from restaurants and food operators ends up in landfill.
Capturing this organic waste isn’t cheap, requiring organisations to invest in separation and capture, and processors like EnviroWaste, to scale up capacity to deal with newly separated material.
However, economics improve as councils roll-out kerbside food scraps collection services and the government increases the waste disposal levy on every tonne of rubbish entering a landfill.
Inevitably, both city residents and private sector organisations will shoulder some of the cost to support new collection schemes. But good things are happening – it just takes time and broader recognition that slashing the volume of compostable material ending up in landfill puts carbon back in the soil and reduces methane. Worms love it, too!
By Carl King, General Manager Post Collection, EnviroWaste
Pictured below: EnviroWaste's composting facility at Hampton Downs