15 November 2024
Water Conservation Series – Microfiltration with Fungi
We have all heard of water filters, and many of us use them in our homes. But did you know that mushrooms can be used to filter water?
In this edition of our water conservation series, we explore how fungi, with their unique design, play a significant role in reducing contaminated wastewater.
How Fungi Are Designed
Looking under a microscope, fungi cells are about 0.5-2 microns wide whereas human hair is about 50 microns wide. These cells grow as interconnected webs, resembling netted fabric, much like with regular filters made of fibrous material.
What They Can Filter
Research has shown that certain fungi are particularly effective at filtering contaminants from water and soil. There are two standout species - Stropharia rugosannulata known as the Garden Giant, and Pleurotus osteratus, the oyster mushroom.
The Garden Giant has proven especially adept at degrading polycyclic aromatic hydrocarbons (PAHs), harmful compounds found in substances like fossil fuels. In a test on a waterfront farm, this mushroom reduced coliform bacteria – a harmful bacterium commonly found in animal waste – by 100-fold, significantly reducing the impact of contaminated water downstream.
Similarly, the oyster mushroom has demonstrated strong performance in laboratory tests, showing the ability to break down hydrocarbons. After the 2007 San Francisco Bay oil spill, fungi filters, including oyster mushrooms were used removing 70-84 percent of the PAHs. Beyond water and soil, fungi can also filter the air.
Benefits
With approximately 80 percent of the world’s wastewater being left untreated before making its way into waterways, fungi filters offer an inexpensive and simple way to reduce contaminated wastewater. On a larger scale, they require low capital and minimal maintenance costs.
Can You Make Your Own?
You can, have a go and create your own fungi microfilter. They can be simply made with a hessian sack, filled with some woodchips, and inoculated mycelium. They can be placed around water ways around farms, urban areas, roads, and factories.
Incorporating fungi-based filtration methods not only highlights an innovative approach to purifying water but also emphasises the importance of conserving this precious resource by preventing contaminants entering our waterways. Their natural ability to filter contaminants such as heavy metals, hydrocarbons, and harmful bacteria from water and soil offers an eco-friendly solution to one of the world's most pressing environmental challenges.
