Researchers explore using sewage waste to combat algal blooms

Scottish collaborative project utilises circular approach to produce biochar and filter phosphorus from wastewater.
Filtering phosphorus from wastewater could help to prevent harmful algal blooms.

Filtering phosphorus from wastewater could help to prevent harmful algal blooms.

Photo: Industrial Biotechnology Innovation Centre (IBioIC).

Scientists in Scotland are investigating a novel approach to combat eutrophication and algal blooms in water bodies by converting sewage sludge into biochar.

Biochar is a charcoal-like substance created when materials such as sewage sludge are burned at high temperatures and deprived of oxygen.

Funded by the Industrial Biotechnology Innovation Centre (IBioIC) and Scottish Water, the project found that biochar-based filters were highly effective in removing phosphorus, a key nutrient contributing to algal blooms, from wastewater.

This suggests the potential for large-scale water treatment applications to prevent algal blooms forming where wastewater is discharged, the researchers say.

Combating harmful algal blooms while recovering phosphorus from wastewater

"While phosphorus causes challenges for the environment and sectors such as aquaculture because of its impact on algal blooms, it is also an element that we all use in everyday products. Natural stores are depleting, so this circular bioprocess could lead to new opportunities to recover the nutrient from wastewater and create new supply chains here in Scotland," said Dr. Szabolcs Pap, the project's lead academic, in a media release.

“At the same time, water companies are under increasing pressure to reduce waste and find alternatives for bioresources from sewage, so there is an additional benefit in terms of sustainability. Biochar can be a valuable material with a range of potential applications, but the global market is still in its infancy. The approach to recovering phosphorus we are exploring in this project is just one example of what it can be used for.”

Project could pave the way for commercialisation of biochar in Scotland

Scottish Water is providing the raw materials to produce the biochar, which is then tested at Scottish Water Horizons' Waste Water Development Centre in Bo’ness, with input from the Environmental Research Institute at UHI, North, West, and Hebrides, and water treatment specialists AL-2 Teknik.

The next research phase will involve on-site tests at smaller Scottish Water treatment works and discussions with regulators about commercializing biochar.

“This collaboration demonstrates how one type of waste can be used for the benefit of the natural environment, treating issues like algal blooms which are posing significant challenges as climate change continues and water temperatures rise," said Dr Liz Fletcher, director of business engagement at IBioIC.

"Although the creation of biochar is still in its infancy, we see huge potential for a growing market that could help several industries to reduce waste and adopt more circular processes," Fletcher added.

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