It can take hundreds of years for plastic to degrade alone, but nature may already have answers to our problem. For some organisms, plastic debris offers a food source; for many others, a literal life raft. When 8 to 10 million metric tons of plastic end up in the ocean each year, some of it provides a home to entire biological communities.
There are more than 170 trillion plastic particles – with a combined weight of over 2.33 million tonnes – currently floating in the world’s oceans. Today, plastic marine debris is found in all five major ocean gyres, and in the Southern Ocean. Gyres are areas of large circulating ocean currents that act like a vortex, causing floating waste to be gently drawn into their core.
Microalgae have been gaining attention as a sustainable, less energy-intensive method for wastewater treatment. This involves growing them in the effluent, where they consume compounds containing nitrogen and phosphorus, as well as heavy metals, pesticides, and particular toxins. Microalgae view these as valuable nutrients, effectively removing pollutants from the water.
When we think of pollution in streams and rivers, we tend to think first of rubbish in water; the litter traps along the Yarra River in Melbourne’s CBD that are often overflowing, or the empty plastic bottles along the Moonee Ponds Creek. But water pollution takes many forms, from physical trash to invisible chemicals that accumulate in our waterways.
Victoria can simultaneously solve Melbourne’s future sewerage crisis whilst building a sustainable carbon credits sector. A common sight for Melbourne’s residents in the 1850’s would have been carts full of “nightsoil” trundling down Flemington Road. Melbourne subsequently built one of the world’s best municipal water systems, supporting the quality of life its residents enjoy today.