Researchers at the University of Gothenburg have discovered a groundbreaking application for fish waste by converting it into biogas, providing both an energy source and a nutrient-rich fertilizer for aquaponic farms. In aquaponics, a system that integrates fish and vegetable farming, the nutrient-rich water produced by fish traditionally has been considered a byproduct with little value. However, the researchers found that by breaking down fish waste in an anaerobic environment, they can produce biogas consisting of 70% methane, which can be used as a fuel in aquaponic farms.
Victor Lobanov, a doctoral student of marine biology at the University of Gothenburg, explained, “By breaking down fish faecal matter in an anaerobic environment – known as digestion – we can obtain a concentrated gas mixture of 70 percent methane that can be used as fuel. This can make aquaponics a source of energy.”
The study also highlighted that the nutrients released during the digestion process are more readily available to plants compared to synthetic nutrient solutions. Fish waste, which contains valuable nutrients, has the potential to contribute to more sustainable food production in aquaponic systems.
Additionally, the biogas produced contains carbon dioxide, essential for plant growth in enclosed spaces like greenhouses. The researchers plan to initiate a pilot project in a commercial aquaponics facility this summer to assess the system’s resilience and guide the development of modular digestion systems that can be integrated into existing aquaculture and aquaponic setups.
Beyond aquaponics, the researchers believe this technology could find applications in other animal husbandry sectors, such as piggeries. The residual sludge from the digestion process remains highly nutritious and can be used as traditional fertilizer for fields, presenting an innovative solution to waste management challenges in farming.
“In many countries, the quantity of fertilizer produced in livestock farming is a problem. Digestion of the fish solids reduces the quantity of waste produced by farms while additionally producing energy and a great fertilizer for hydroponics,” Lobanov added. The findings contribute to more sustainable food production methods and address challenges related to waste management in livestock farming, offering a promising solution for generating valuable energy resources.