Every year, every single person in Perth generates around 2.5 tonnes of household waste. Food waste, old newspapers, cans, bottles, plastic and packaging. That’s an awful lot of rubbish. So what happens to it all? Well, rather than being dumped as landfill, this waste is about to have a new lease of life – as something very useful. But let’s start at the beginning – at your place. It’s bin day. And, as you’ll learn later, it’s really important to put the right rubbish into the right bin. The green-topped bin is for household rubbish only – and that’s mainly food and organic waste. So… in it goes …just in time for Mike to pick it up. Each waste collection truck can hold the contents of up to 800 wheelie bins before it’s full. Then it’s off to the Regional Resource Recovery Centre in Canning Vale. Mike’s truck is carrying 9 tonnes of waste – just a fraction of the 350 tonnes of waste that arrives here every day of the week. Once the truck’s been weighed, it’s off to the tipping floor at the Waste Composting Facility. This waste is about to be turned into compost but before the process can begin, things that can’t be composted have to be removed. Here are just a few of the things that people have wrongly put in their green bin. You can’t compost a fire extinguisher! Now you see how important it is to only use your green bin for organic waste. This waste is now ready to be loaded into the giant machines which will magically turn it into compost. You might have a composter like this one at home. It can turn your food scraps into compost in around 3 months. But if you have thousands of tonnes of waste to compost, you’re going to need something a bit bigger – and a lot faster. These giant digesters are the biggest in the Southern Hemisphere. Each one is 67 metres long and weighs 650 tonnes when full. And there are four of them. As they rotate, the waste passes slowly from one end to the other. As it does so, microbes break down the waste in temperatures up to 60 degrees centigrade. In just three days, your waste has broken down into this – the beginnings of a good quality compost. And this is where the final part of the maturation process takes place. This aeration area is huge – the size of two soccer fields and can store 5 ½ thousand tonnes of maturing compost in up to twenty-eight rows. It’s pretty hot and sticky in here as the maturing compost needs moisture, oxygen and heat to help bacteria break it down. As it matures, it gives off a lot of heat. This pile is currently 70 degrees inside; so it needs turning. Thankfully, they’ve got a machine for that. Turning the compost every few days helps it mature evenly and cool. The drying process is also helped by giant fans, which circulate fresh air under the concrete floor. Now, as you can imagine, rotting rubbish can give off quite a smell. So before the air can be released into the atmosphere, it has to be cleaned. First the smelly air is sucked out of these buildings with a giant vacuum pressure system. Next, these humidifiers remove large particles from the air and saturate it with water. Then the air’s pumped through this huge bio filter. Micro-organisms living in these woodchips break down the odour molecules – and the result is clean, fresh unpolluted air. Once it’s been sieved and screened to remove impurities such as metal, glass and larger pieces of plastic, what’s left of your rubbish is a fine brown powder. After 6 weeks, this compost is dry, fully-matured and ready to use. One final screening removes any remaining pieces of plastic, glass and metal – and then the compost is loaded onto transport trucks. And this is where the compost ends up – on the farm. Compost makes a rich, organic fertiliser that’s perfect for feeding above ground crops such as wheat and barley. So instead of becoming landfill, your household waste is now helping enrich the soil, reducing the impact of greenhouse gases, and growing crops which will become the food on your table. And some of that food will eventually end up in your green topped bin. Which, if you remember, is where we started.