New Zealand is in the top 10 waste producers in the world. Our waste to landfill has increased 48% in the last decade.
When we deposit our bags or bins of waste on the curbside for collection, we rarely consider where it goes and what happens to it.
Waste is ubiquitous and problematic, when we dispose of it to landfill it does not get sorted out, and it does not completely go away. It manifests in the form of greenhouse gases; methane and carbon dioxide, and also toxic leachate, an acidic liquid cocktail of chemicals and heavy metals that is rarely contained in landfills, and as many of our landfills in NZ are built near waterways and estuaries, it is clear where it will end up.
Modern landfills are usually lined with high density polyethylene (HDPE) plastic, geotech liners and clay to contain the leachate, however liners ultimately fail. A life of 15-106 years for high density polyethylene liners has been estimated at 350C, average temperature for a landfill (Geosynthetic Institute 2011).
Landfills also produce greenhouse gases; methane and carbon dioxide, which are a by-product of bacterial respiration and decomposition of waste in the landfill. These greenhouse gases can be emitted for thirty to fifty years and are often released into the atmosphere. Although a small number of landfills clean the gases and extract methane to burn for electricity generation.
On closure of a landfill on-going monitoring and remediation is required for up to thirty years via the Resource Management Act.
Numerous landfills have leaked contents in waterways and the atmosphere over the years. I conducted research on Meola and Motions Road landfills in the 1990’s which were prime examples of both leachate and gas escaping from old landfills. More recent instances are Spicer landfill Poirirua, leaking potentially fatal levels of hydrogen sulfide and methane gas in 2015, Levin landfill 2016, Houghton Bay, Ocean Beach landfill Dunedin 2019, Wellington 2020, Fox Rover 2020, Gisborne Te Araroa landfill 2020, Taranaki landfill 2020, just to name a few.
Incineration and waste to energy plants are not a sustainable option for disposal. They can produce toxic ash and particulate matter, greenhouse gases, compete with recycling centres, and for some they need to be fed 24/7 encouraging a throwaway culture.
The New Zealand Government currently charges a $10 per tonne waste levy fee for every tonne of waste to landfill. This is highly likely to increase in 2021 when Ministry for the Environment quite rightly increase the fee. As a comparison, the Waste Levy in Australia is $133 per tonne, in the UK $160 per tonne. This will hopefully start to change the model, as it currently cheaper to landfill than recycle.
Over 3.68 million tonnes of waste went to landfill in 2019 in NZ.
We cannot keep throwing away, dumping, disposing, discarding. We need to do things differently. Taking steps to reducing waste; using cloth bags, avoiding packaging, buying second hand, making things, buying at bulk bins, composting, shopping at farmer’s markets, buying local, contacting manufacturers and producers asking them to change their packaging, signing petitions- look at what happened with plastic bags!
Circular economy ōhanga āmiomio is a concept and practice to unmake everything we make. It’s about designing out waste, keeping products and materials in use and endeavouring to regenerate natural systems. After all we only have one Papatuanuku.