Community composting – think before acting
…by Russ Grayson
A woman walks down the road carrying a couple plastic shopping bags. Reaching a large, tall, green box conveniently located by the footpath, she flips open the lid and empties the contents of her plastic bags, one after another, into it. Out tumbles orange and potato peel, apple cores and banana skins and last night’s leftovers. No illegal dumping this—we are witnessing a new phenomenon in our cities—community composting.
Kitchen and garden wastes, which make up almost half of our domestic waste, are known as ‘green waste’ and in a small but increasing number of places the stuff is being tossed into community compost bins. You find two of them adjacent to the wall of the scout hall in the Dolphin Street reserve in Coogee. There’s a lone one outside an apartment block in Waverley, more in Peace Park in inner city Chippendale and they are likely to soon appear in a couple other local government areas (LGA) in Sydney, on a trial basis at first. So as not to feel left out down south there’s a possibility that they will soon be found on the streets of Port Phillip local government area.
While it is usually local councils that install community composting bins, the lone bin in Waverley is the initiative of Sarah van Erp, a young woman who said farewell to her native New Zealand and now lives in Waverley. Sarah is one of these people who love garbage. She loves it so much, in fact, that she became a revolutionary, joining the Three Council (Woolahra, Waverley, Randwick) Ecological Footprint Project’s Compost Revolution. ”
Sarah installed an Aerobin composter, a type favoured for community composting, though that may be due more to people copying what others are using than any objective selection process. Irrespective of the type of composter used, community composting has the potential to address the waste recycling need of those who live in apartments.
Councils: apply a little systems thinking first
For councils considering community composting, it’s a good idea to apply a little systems thinking before jumping in.
First, we think about the inputs to the community composting bins. What will people put into the bins and how much of it is there likely to be?
The first part of the question will suggest whether we need to supply other materials to put into the compost to achieve the needed mix of green and brown (nitrogen-rich and carbon materials. The latter part of the question will determine how many bins the council installs.
Next, we come to the question about process—about how the composting process will be managed.
Much depends on the type of compost bin installed. So far, the Aerobin has been the preferred model but there are other possibilities. Aerobins are rapid composters that, in theory, do not require the compost to be turned. Our experience with the Chippendale Aerobins is that the process benefits from regular turning with a composts screw.
What is needed are enthusiastic composter volunteers to ensure that the bins function well. Arcane it might sound, there are people out there walking our streets who are compost mavens, closet compost lovers who like the stuff so much that they will voluntarily form themselves into composting crews and keep an eye on the bins to ensure that they are working well. These people are the critical ingredient in community composting.
The final stage in our systems thinking model is about outputs—the compost we produce in our public place compost bins. It’s little use producing compost if we have nowhere to use it, and it’s salutory to remember that one of the duo who invented the Permaculture design system, Bill Mollison, told us that an unused resource can become a pollutant. That’s how it is with compost, a valuable resource for our home and community gardens but a source of nutrient-rich pollution if it is stored unused and is washed into our stormwater system when it rains.
We need somewhere to use our community compost. There is much to be said for placing community compost bins at community gardens where the stuff will be used, however there’s no reason householders could not take a share, especially if they contribute their kitchen wastes to the bins.
If we are making use of systems thinking as a means of working out how to manage our community compost, there’s something else that is a characteristic of systems. This is feedback loops that allow us to monitor how our compost is working, the quality of the compost produced and to feed back corrective information into the production process so that we can tweak and improve it.
This is called ‘corrective feedback’ and it’s the opposite to ‘reinforcing feedback’ that accelerates a trend further in one direction and that can make errors so much worse. In managing our community composting, the feedback loop is made up of monitoring, of periodically checking, how our compost is working and the quality of the compost produced. If the quality is not so good, then we feed that learning back into our production process by taking measures to correct whatever is wrong. All good ideas need feedback loops.
A popular idea
There are now community composting facilities being tried out in a number of local government areas. All of these use the Aerobin technology, but as I said earlier, there are other types of composters that could be used.
How well do the Aerobins work? Overall, very well. However, the Aerobins are tall enough to make is potentially difficult for children or shorter people to access them effectively and, in Sydney, there have been cases of cockroaches breeding inside the bins.
Monitoring of the Chippendale community composting bins in Peace Park by staff from the City of Sydney dis closes that most of the material being put into community compost bins is kitchen scraps. This is nitrogen-rich material and it can become sloppy and requires the addition of carbon-rich material such as wood shavings, shredded newspaper of straw to produce a better acidity/alkaline balance.
Community composting is something new on our city streets and the idea is best regarded as being in what I call it’s ‘rapid prototyping’ phase. During this phase the system is trailed and debugged before being scaled up and more facilities installed.
What is ideal is that the facilities are monitored, a record kept of their performance and, after a year or so, the idea is evaluated. This allows it to be scaled up based on the knowledge learned during rapid prototyping.
You could say that our city has a wasteful future, but that’s waste-become compost thanks to the enthusiasm of community composting mavens and innovative councils working together. We have learned that care needs be taken in locating the compost bins as they will likely get better use when placed where a larger number of people live, especially near apartments or other medium density areas.
More on community composting