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[Kendall Ferraro]: If you've ever driven along the freeway near Craigie, you've probably noticed there's an unusual building hidden in the bush. I'm going to show you why facilities like this are so important to our community. So, you flush the toilet, have a shower, or pull the plug on the sink and the water just heads down the drain.

This used water is called wastewater, and this is where its adventure starts. On average, each of us produces about 200 to 300 litres of wastewater every day. That's enough to fill a bathtub. While 99.97% of the wastewater is actual H2O, there's also oil, grease, detergents, nutrients, bacteria and bulkier items like wet wipes and cotton buds, as well as some other pretty nasty stuff that should never make its way into our pipes.

Once you've sent your wastewater on its way, it flows by gravity or is pumped through your household pipes into a network of larger pipes called sewer mains, before making its way to one of our wastewater treatment facilities like the Beenyup Resource Recovery Facility in Craigie.

When it gets to the plant, the wastewater comes in through here, the main inlet pipe. Each day millions of litres of wastewater makes its way through this pipe from schools, homes and businesses in the area.

Our job is to make sure the wastewater is treated and safely returned to the environment. We do this in the most sustainable way possible. The flow of incoming wastewater changes throughout the day and night, depending on what we use in the community.

There are definitely peak poo hours and the wastewater treatment plant needs to be ready for it. All running plant and equipment is monitored in our control room, 24 hours a day, 365 days a year by our highly trained engineers and plant controllers.

There's a saying around here, if you can see it, you can smell it. That's why all tanks and pipes at the plant carrying untreated wastewater are completely enclosed. The odorous gases are extracted using huge air pumps and vents that push the gases through filters called odour scrubbers.

These filters remove almost all of the bad smells. The treated gases are then released through a 50-metre-high stack.

Now onto the wastewater treatment. There are a few different ways to treat wastewater. We choose to do it the natural way. We mostly use simple physical and biological processes, and this is where it all starts.

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I know you want to see this, the first screening process which collects things that shouldn't end up in our sinks, toilets and drains. None of these items can be treated or recycled so, sadly, they end up as landfill.

Gross. The most common things that get caught by the screens are wipes, earbuds, rags, plastic and general rubbish. Sometimes we find other things. We've pulled out false teeth, wallets, money and even toys like this little guy. These huge bins are filled with literally tonnes of the non-organic waste which is picked up in the screening process.

Trucks come to collect this rubbish every two days, but a lot of this waste can be avoided if we all do the right thing and remember to only flush the three P's. Pee, poo and toilet paper. And of course, there's a fourth unofficial P, puke. That's okay too.

Next is the primary treatment which takes place in sedimentation or settling tanks. This tank is uncovered because it's no longer in use, but you can get an idea of how it works. Inside each tank, solids sink to the bottom, forming sludge.

Mechanical scrapers push that sludge to the end of the tank where it is removed. Meanwhile, fats or oils floating on top of the water surface are skimmed, collected and also removed. The wastewater then flows through to the next stage called secondary treatment.

The sludge, however, heads off on a completely new journey which we'll see later on. By now, the water is largely sludge-free and ready to work its way through a network of aeration tanks. In these tanks, good microscopic bacteria called microbes really go to work to further break down any remaining nutrients and organics in the wastewater.

Where do these microbes come from? They originally come from your stomach. You donate some of your stomach microbes to the wastewater facility every time you relieve yourself. At our facilities, your microbes basically do the same job they do in your stomach, just at a much larger scale. Thanks for your contribution.

At the plant, we further cultivate specific microbes that we want to use in the treatment process. When a new plant comes online, we collect the good cultivated bacteria from another plant to start the biological process for treating wastewater.

This process is called seeding. These aeration tanks need to be constantly aerated using oxygen in these pipes into fine membranes on the floor of the tanks. The oxygen is essential for the good microbes to survive and play their role in breaking down the bad guys.

You can see all the aeration tanks are completely covered. This is to stop the last of any unwanted odours escaping into the air. But from here on, things are nicer on the nose as the odourless water emerges into the light.

This is the final part of the process just here below our feet. These are the secondary sedimentation tanks, where the water is clean enough for ducks and other bird life to enjoy. And they love it too.

At this stage, the water goes through a slow flowing system to separate the remaining sediment. This is removed and mixed with the rest of the sludge separated in the earlier processes. So exactly what happens to the sludge? It's rich with nutrients but still needs further treatment before it can be safely reused. It's broken down by bacteria in these heated digestion tanks.

The sludge is then put through a centrifuge, which spins the sludge around really fast, removing the excess water and turning the sludge into biosolid cakes. It's definitely not the sort of cake you dish up at a birthday party, but it's certainly very useful when processed and served up as a fertiliser in places like tree farms and canola fields.

But the sludge hasn't finished giving just yet. Whilst being digested in the tanks, it emits a collection of gases called biogas. At the Beenyup Resource Recovery Facility, the biogas is used to heat the digester tanks and also power other parts of the plant.

Given that the biogas is a collection of carbon dioxide and methane, you could say this facility is partly run by fart power. We recycle as much of the biogas as possible because, as you probably know, methane and carbon dioxide are both potent greenhouse gases, and too much of these types of gases in our atmosphere can contribute to climate change.

You've probably noticed that we reuse as many materials as possible. This is to reduce the impact of our operations on the community and our environment. But now we've treated all of this water, where does it go?

Some of the treated water flows via pipes to the ocean, but a large portion head over to our Advanced Water Recycling Plant where we further treat the water and actually return a portion of that to our underground aquifers.

The goal here at Beenyup is to recycle as much of our treated wastewater as possible, creating a more sustainable water cycle. The water that does go to the ocean travels via a long outlet pipe. The submerged pipe has lots of small holes along it to evenly disperse the water out to the sea. To make sure the marine environment stays nice and healthy, regular monitoring and testing takes place. Here at Beenyup, a large portion of that treated water heads over to our neighbours at the Advanced Water Recycling Plant. Where it ends up and what they do with it is another amazing story in our water world.

You can find out more by visiting our website.