Michael Mobbs - Sydney's Sustainable House

Public composting in Chippendale

Here is a report on the first six weeks trial of public composting in Chippendale.

The trial is part of the strong support from Mayor Clover Moore and council staff for our road gardens.  Mayor Moore recently planted fruit trees in Myrtle Street and has strongly supported our food road gardens with a clear new Council policy.

There are seven 400 litre Aerobins in Peace Park.  Each bin handles 3 tonnes of food waste a year and makes a tonne of soil compost.  The bins handle citrus, onions, paper, grass and rely on heat not worms to break the waste down.

These seven bins plus the other 6 in the nearby streets mean that we are keeping over 40 tonnes of food waste out of garbage trucks, making over 13 tonnes of soil compost to grow our local food, and cutting over 10 tonnes of greenhouse pollution a year.  The nutrient juice from the bins will increase the productivity of the gardens.  These savings are achieved at no cost except our own gardening labour.

Council’s Waste Officer, Michael Neville, is providing advice and support and helping us to document the trial.  Here are some notes of progress to this week prepared by Michael:

• Michael M, Matthew and myself met on site at 3.30 pm for an initial investigation of all bins. We found that the original carbon layer we put down had worked really effectively in stopping the soggy anaerobic conditions of the original bins - pre trial and extra bins
• We gave all the bins a really good turn to mix materials, added carbon (shredded cardboard and straw) and water
• There were minimal odours and contamination (a few aluminium cans and a couple of beer stubbies)
• A couple of days later I went back and gave each bin about 5 litres of strong worm juice as an activator - more about that later…
• I reckon that between 3.30 and 7.30 pm about 350 people passed through the park (the kiddy people, followed by the doggy people interspersed with the travellers heading in all directions)
• We spoke to 5 groups of people depositing food…most seemed to bring about 2 litres worth - all were very keen and committed;
  • Antoinette walks up from Pyrmont and brings her food scraps in her back pack a couple of times a week
  • The family of three bring 2 L ice-cream containers most days
  • the older woman checks that there’s room before bringing her scraps
• We spoke to about 20 different people - there was only one negative comment about odours - everyone else was incredibly positive…also lots of interested observation of us…
• We also had a teacher from Lakemba wanting composting info for his school

So our super thermometer probes arrived this week and I went to the park for the first check of bin temps on Tuesday the 9th. As a measure the Aust standard for commercial compost is 55 degrees c for three consecutive days. Readings on the bins right to left: Sunday bin = 51 cSat bin = 42 cFri bin = 50 cThu bin = 49 cWed bin = 57 c [highest temp - bin 6 days maturing when measured]Tues bin = 38 cMon bin =  38 c
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The idea Michael Neville had of providing one bin for each day of the week seems to be working so far.  It’s an easy message for anyone to ‘get’ in the park when they use the bins.

Anyone may use the compost.  It will be ready at the end of March.  Just lift out the lid at the bottom of the bin and take it, clean up after yourself and leave the bin lid well secured so it doesn’t fall open.

We will use the compost for the espaliered fruit trees in the park and for the food plants in our road gardens.

May no waste be with you,
Michael