Australians are the best household recyclers in the world. Our domestic kerbside recycling rates are second to none. But even so, we still put about 15-30% of all recyclables into the wrong bin. That is, into the garbage bin instead of the recycling bin. By Mike Ritchie.
In NSW, this loss of recyclables accounts for 30% of all generated household recyclables.
To put this another way, 23% by weight of the garbage bin is recyclable product that should not be there (NSW EPA 2013).
MRA Consulting Group has described this loss of recyclables to the garbage bin as “leakage” to differentiate it from “contamination” (which is garbage in the recycling bin).
There are essentially three reasons for “leakage”:
- Lack of education; (“I don’t know”)
- Unwillingness to participate (“I don’t care”); and
- A lack of recycling bin capacity (“I don’t have enough space”).
The latter is easily identifiable and remedied. Approximately 15% of households in Australia regularly fill their 240 litre recycling bin to capacity (State Waste reports 2007-11) prior to pick up.
For this group of households, the question is “would a bigger, or a second, recycling bin reduce leakage and result in higher recycling rates?”.
MRA undertook a research project to test this question with the generous support of SULO, the NSW EPA, Rockdale City and Sutherland Shire councils in 2012-13.
We replaced 400, 240 litre bins with 360 litre bins and compared the results to an equal number of control households. We also compared households with 2, 240 litre bins to the controls but that is the subject of another article.
Over five months (winter and summer) we weighed the bins to determine whether the test bins (360s) varied from the controls (240s).
The key findings were:
- There was a 6% increase in the average weight of recyclables per lift and a 10% net decrease in the average weight of garbage per lift presented by households using a 360 litre recycling bin (see fig 1)
- The increase in household recycling yield with a 360 litre bin in mid-summer could be as high as 15%;
- However, the increase in the weight of recyclables and decrease in the weight of garbage was not statistically significant due to the limited sample size (400 households at 95% confidence);
- The cost of the new 360 litre bins is more than compensated by improved recycling rates driving reductions in landfill disposal costs (more than $300/t of waste landfill cost in Sydney);
- Similar outcomes could be achieved by the provision of a second 240 litre recycling bin but the collection contractor would most commonly charge an additional lift cost;
- So long as the contractors lift costs for a 360 bin are the same or a slight premium on the 240 bin, then 360 litre bins are a more commercially attractive option; and
- Supplying 360 bins to all households (and not just those that need it) was not as cost effective as it increases capital costs of bins without necessarily recovering additional recyclables.
Fig 1. Average recycling and garbage generation (kg) per bin lift, per household over the audit period.
The study concluded that providing 360 litre bins to those households that need it (i.e. the approx 15% of households that regularly fill their recycling bin) was an important innovation to improve recycling rates. Government grants are often available to support such innovations.
Councils should examine the cost benefit of selective provision of 360 litre bins based on their specific demographics, geography and existing recycling rates.