Now there is a proposal to put local food waste to use by mixing it with Ganoderma steyaertanum mycelium and making floating wetlands-cum-rubbish traps for the Yarra River.
Ben Edwards, a British architect who has lived in Melbourne for more than a decade, has designed tear-shaped islands that would effectively catch waste with waste.
Edwards’ architecture and design practice Studio Edwards came up with the project for the professional category of the Waste Challenge, held earlier this year as part of the National Gallery of Victoria’s Melbourne Design Week.
While the industrial design agency Studio Periscope took out the challenge for a piece of primary school playground equipment that doubled as a hot composting system, Edwards says positive feedback about his wetlands proposal – one of four projects shortlisted – has encouraged him to “keep the conversation going”.
With a spot off Southbank identified as one potential site for his part-science, part-gardening-on-the-river initiative, Edwards is now seeking funding for its development and fabrication. He anticipates the floating mycelium-food-waste platforms would be constructed in a laboratory over about five days.
A dampened mix of one part mycelium to 10 parts waste would be placed into a series of sealed triangular moulds – with air holes to allow the mycelium to grow. The moulds would be kept at the ideal temperature and humidity level for the mycelium to entirely colonise the waste, at which point a thick white skin would have developed around and inside it.
The resulting structure would be baked in an oven, killing the mycelium and resulting in what Edwards describes as a rigid but relatively light object that would have the feel of expanded foam. There would be a scooped-out area on the top (for the plants) and holes through its base (to allow the roots to grow into the river.)
The modules would be painted in linseed oil (to improve water resistance), pinned together to form an ‘island’, filled with a lightweight growing medium and planted with native aquatic species that would provide habitat for wildlife and help purify river water by absorbing excess nutrients. Anchored in pairs, a steel mesh trap would be placed in between two islands to capture floating litter.
Edwards says it’s a low-tech and low-environmental impact solution that is visually attractive and would help alleviate the “severe stresses” placed on the Yarra from pollution, development and the other downsides of increasing urban density.
While he anticipates the mycelium-made modules would need to be replaced every year (they would be removed from the river and left to break down on land) they are, he says, both more sustainable and more beautiful than the “horrible” metal traps currently in use.
They tie in with his interest in ‘future living’ and how we might design our cities in such a way that they can accommodate higher populations while providing engaging public spaces.
“The idea of ‘future living’ is not necessarily thinking about the house you live in but about the city you live in, including its parks and amenity spaces. You see the Yarra all the time, it runs through the city but it can be pretty grisly. The river is prime wildlife habitat and a public amenity and we need to think about how people might become more engaged with it.”