Published on 21 October 2019

Green turns into black gold

Have you wondered about what happens to your lunch leftovers or your grass clippings once you put them in the bin for kerbside collection?

Confused as to which bin to put your leftovers? Red, yellow or green? We ask Lynda Wedding, City of Onkaparinga’s Waste and Recycling Education Officer, to demystify the dilemma and explain why waste is such an important resource.

In addition to garden cuttings, what else can we put the green organics bin?

All food scraps — fruit and vegetables, seafood, meat, bones, dairy and processed foods. These are eminently suitable for commercial composting, where materials break down quicker than in a home compost system.

Anything else?

Coffee grounds (not pods); tea bags, but not the silky looking ones because they’re actually made from the same plastic as soft drink bottles; cold ashes and charcoal; clipped nails and hair, including pet hair and dog waste (no plastic bags though); iceblock sticks; wooden tooth picks; and bamboo plates and cutlery. As a general rule, if it grows, it can go in the green organics bin.

What about pizza boxes?

We get asked this a lot because people are concerned about the oil that leaks into the box. But the answer is, you have a choice. If it’s empty and clean, then the box can be recycled and go in your yellow-lidded bin, otherwise pop it in the green organics bin.

Shredded paper?

Green organics bin, definitely. Imagine the recycling sorting facility; it’s a big open-air building where trucks offload material onto a conveyor belt, but if it’s windy it creates a small cyclone and smaller bits of paper blow around like confetti, damaging machinery. The general rule is if the paper is smaller than a post-it note, then it goes in the organics bin.

What organic items can’t we put into the green organics bin?

Cooking oil is a hazardous waste, so you can’t pour in oil that you’ve fried your chips in. But if you’ve wiped up oil with a paper towel, it can go in the organics bin.

Can we put food scraps in compostable bags?

Yes; plant-based compostable bags will be available from council, free, from December this year until November 2020, but similar bags are widely available in stores.

However, there’s a lot of confusion out there with brands claiming to be enviro-friendly, yet their products are still mostly fossil fuel-derived plastic. Look for the word ‘compostable’ and the Australian seedling logo on the packaging. If it meets these standards, it can go in the green organics bin. If not, it can’t. 

What happens to the organics once it’s picked up?

We have a contract with Solo Resource Recovery, which delivers our organics to Peats Soil and Garden Supplies where it is hot composted to neutralise weed seeds and viruses. This means you can put things in the green organics bin that you wouldn’t put into the home compost like soursobs, caltrop and black spot-affected roses. The matter is then mixed with other materials such as manure, chicken carcasses, and absorbents like wheat husk, to become a delightful plant food.

How beneficial is compost?

It’s an excellent soil conditioner. It provides essential nutrients for growing plants but also improves soil structure and its ability to retain moisture. Micro-organisms love it. So do the farmers, gardeners, and the environment. Basically, it’s black gold.

VIC reduces food waste

The City of Onkaparinga is at the forefront of sustainable practices with its tourist hub — the McLaren Vale and Fleurieu Visitor Information Centre (VIC) ­— located in the heart of Australia’s most sustainable wine region.

It’s therefore no surprise that the VIC’s in house café strives to close the loop on food waste.

More than 100,000 people visit the VIC each year, with its café catering for visitors, locals and events. That’s a lot of food preparation. And it could mean a lot of waste ending up in landfill if it wasn’t for the café’s efforts to combat this problem.

All food waste is separated into the green organics bin, joining other compostable products such as serviettes, cardboard straws and packaging. Coffee grounds are a great soil conditioner, so they are set aside for local gardeners to collect or are mixed into the compost for the on-site kitchen garden.

“It’s wonderful to be able to pick fresh and seasonal produce straight from the garden for our café menu — herbs, fruit and veg,” says café attendant Stephanie Morris.

“We also try to reduce our carbon footprint and food waste by shopping locally, sourcing regional produce, and diligently separating our food waste so it can be commercially composted to help local farmers grow more nutritious food, which we then buy.

“We’ve still got improvements to make, but we’re working towards reducing our impact on the environment and sharing our journey with our community and visitors.”


  • From 1 January 2020, green organics bins will be collected fortnightly rather than every four weeks. 
  • Residents can pick up free compostable bags from the council from December 2019.
  • Visit the council’s waste and recycling guide.
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Solo Resource Recovery delivers organic material to Peats Soil