Waterfront: ‘Mushi’

Mushi developed upon the idea of a 'floating wetland', initially conceptualised by Studio Edwards for the 2019 Victorian Design Waste Challenge. The concept aimed to address waste by creating a mycelium based floating wetland made with organic waste to harbour water-cleaning plants for purifying the river, providing a habitat for wildlife and host litter traps to clean waterways. As the benefits of artificial wetlands are well established, this design research trials a floating mycelium-based structure. It materialises the concept and creates a tangible opportunity to test and assess its feasibility, buoyancy, durability, scalability, structural capacity, and effectiveness in maintaining waterways.

The design outcome is 3x800mm diameter triangular-shaped modules. The modules are made with a bio-composite material composed of mycelium and sawdust. While mycelium can colonise and digest a range of cellulose materials, sawdust was used as the substrate for its linear and fibrous forms, which when bound by mycelium results in greater material strength. The mycelium material is set within specially designed moulds that expand to form the structure of the floating wetland. Above the surface, native wetland plants were grown within the compound to create habitat for insects and birds while the roots penetrate the base for water purification.

Artificial wetlands have a positive impact on improving ecological systems by harbouring plants that purify wastewater whilst creating habitats for wildlife. In addition, this prototype embraces the concepts of circular economy mimicking the material cycles in a natural system. The bio-composite used to construct the wetland is grown using a waste product/by-product from another industry process. The waste materials are upcycled into a new product with minimum energy input. The biodegradability of the organic matter means that the wetland end of product life can be returned to the soil and transformed into nutrients and fed back to the natural ecosystem.

An additional internal timber structure is integrated inside the mycelium composite in order to handle the potential tensile forces incurred on the connection points between the individual modules of artificial wetlands. This will effectively mitigate the pulling forces imposed by the waves, wind, or animal movements. The natural wood product can be colonised by and bound with mycelium, thus maintaining the structural stability of the network of artificial wetlands. Three different types of timber were tested in the prototype, they include soy laminate poplar, CD structural ply and Low formaldehyde poplar. While mycelium-based product development has emerged in recent years, its durability has never been tested in an open natural environment while submerged in the water. Therefore, three different surfaces treatments have been applied to each of the individual wetland modules to gain a better understanding of the mycelium composite's durability, integrity, and buoyancy performance. The mycelium composite surface treatments included: organic hard wax, charred, and naturally untreated. Finally, the wetland features three types of Victorian Indigenous plants. The wetland houses Juncus gregiflorus Juncus procerus and Juncus usitatus which are known to provide habitat and food for species such as birds and frogs (Centre for Australian National Biodiversity Research, 2006)