Monday, February 17, 2014

Improving water quality on the River Wandle

Mycofiltration Project - a pilot study using fungi to filter water from road runoff before it enters the river.

The experiment involves installing hessian sacks filled with mycelium at various sites along the Wandle and monitoring the water quality before and after.

We are using blue/grey oyster mushroom mycelium for this project because it is widely available and displays vigorous growth. It is also particularly good at concentrating heavy metals and hydrocarbons, which are two key pollutants from vehicle exhaust found in road runoff water. It is also good at absorbing excessive nutrients and silt that can cause problems in watercourses. It is harmless to people and wildlife.

The first step is to pack some hessian sacks with a layered mixture of damp straw, wood chip and fungi. Then we pop the hessian sacks into plastic bags to help retain moisture and protect them from the elements a bit. After a few weeks the spores should generate mycelium throughout the sacks at which point they will be moved to the test sites.

Unloading the equipment and getting set up.

Sutton Ecology Centre

The magic ingredient - the mushroom culture.

Weighing out the spores

The straw bales needed unbundling and soaking prior to layering into the sacks with wood chips and spores.

Soaking the straw

The first few sacks helped test out the ratio of substrate to spores.

Filling the first sacks

We will take the sacks home and leaves them in the garden checking twice a week until the spores start to sprout.

The first four sacks

Once the white threadlike patches of mycelium have appeared all over the hessian sacks, they will be ready to install at the study sites. This may take several weeks, watch this space...

UPDATE: There will be a follow up session, see Straw bale packing and collection day - Sat 22nd Feb, Sutton Ecology Centre SM5 3NY for more details.

The Wandle Trust is an environmental charity dedicated to restoring and maintaining the health of the River Wandle and its catchment. They hold community river cleanups on the second Sunday of every month, up and down this unique urban chalkstream – pulling out everything from shopping trolleys to shotguns, and improving the environment for birds, fish, insects and local people. For more visit:

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