Over one third of our waste in the Bay of Plenty is organic or ‘biodegradable’. That amounts to over 52,390 tonnes of valuable nutrients being lost each year – contributing to the pressing global issue of soil erosion. Thats not all. When this type of waste goes to the landfill it rots under anaerobic (without oxygen) conditions, giving off methane gas. Methane is considered the biggest threat to climate change and is 23 times worse than carbon dioxide. As if that wasn’t enough, the liquid by-product of organic material rotting in landfills is leachate, which is toxic and leaches down into our soils.


Organic matter bio-degrades, which means it can be returned to the earth to be used again! This can be done in many ways, with various costs and benefits.

Common solutions are:

  • Mesophilic composting – using microorganisms to break down matter slowly.
  • Vermi-composting – feeding matter to worms and harvesting their ultra fertile castings.
  • Thermophilic digestion – fermenting matter at higher temperature.
  • Feeding to pigs – not ideal as this can promote the spread of disease, parasites and pathogens. Not to mention methane from the other end of the pig!


At Why Waste we commonly adopt the first two approaches. However the big plan is to direct the Bay of Plenty’s organic waste stream into a thermophilic digester, which produces not only amazing compost but a source of powerful fuel. This fuel can be used to generate electricity, power vehicles, produce heat – the Bay’s very own source of renewable energy!

For a project on this sort of scale we’d need a lot of organic waste. So for now, we need to focus on finding where this waste is produced and setting up a reliable way of collecting it and diverting it away from the landfill and one day use our kiwi ingenuity to put a whole new meaning to the idiom “one mans trash is another mans treasure”


Information from ’The New Zealand Waste Strategy, Towards Zero Waste and a Sustainable New Zealand’, Ministry for the Environment, March 2002, www.mfe.govt.nz


Anything bio-degradable:

  • vegetable and fruit scraps
  • cooked meat scraps
  • cooked bones – small to medium in size
  • shells – oyster, mussel, clam, crab, egg
  • breads and baking products
  • cheeses, desserts and cream
  • coffee grounds and filters
  • nuts and cereals
  • pasta and rice
  • tea bags and tea leaves
  • flowers, plants and green waste
  • unbleached paper hand towels and serviettes
  • compostable packaging