There are some easy gains to be made in cutting out waste, reports Tom McKinlay.
Waste minimisation sounds at first meeting like something of an oxymoron. It implies an alternative: waste maximisation. And who would be stupid enough to do that? Everyone minimises waste as a matter of course, surely?
Well, session three of the Sustainable Living Programme's eightweek course provides some evidence that a little more minimisation might not be so hard to achieve.
Indeed, of the 300kg of material each person in Dunedin puts out on the roadside each year, only 41.3% is not capable of being recycled. Almost 40% is compostable and about 20% could go to the recycling centre, including cans and plastics one and two.
The Dunedin City Council knows this because it has been going through the black plastic bags left for it to pick up, auditing the contents.
That 300kg is down from 400kg, indicating recycling has picked up, but there's obviously still some way to go.
The 38.6% of compostable content is a particular concern because of its part in producing leachate and methane at the landfill. Methane is a more damaging greenhouse gas than carbon dioxide, while leachate will carry any nasties in the landfill into waterways.
Much of the compostable material will be from the 17% of food in New Zealand that is thrown out.
Nestling in among last Tuesday's leftovers, there is almost bound to be a few items of that ubiquitous substance, plastic.
You know the ones, PET, HDPE, PVC, LDPE, PP, PS and the rest. They are, perhaps, more familiar as the numbers in the recycling triangles. PET is one, HDPE is two, etc etc. ‘‘The rest'' all get lumped under recycling number seven and include bioplastics and polycarbonates.
If you are picking plastics off the shelf at the supermarket, it's useful to know that types one and two (PET, HDPE) are recycled in New Zealand, sent to Christchurch to be granulated. The others go to China.
Those to be particularly avoided include three (PVC), six (PS) and seven.
Dioxin is created in the manufacture of PVC, while plastics in bracket seven are problematic in terms of recycling, so best avoided, as is number six, polystyrene (PS).
So far so straightforward. But there are some further subtleties in the world of plastics.
For example, those cornstarch ‘‘biodegradable'' plastic bags (PLA) that appear, on the face of it, a step in the right direction, are not all they might seem.
For a start, they need an industrial process to biodegrade. Put them on your compost and they'll just sit there. They actually become a problem in terms of recycling streams as a contaminant.
So it is worth keeping an eye on the packaging that seems to come with everything, and leave it on the shelf when you can.
