Clever technologies for clean aquaculture

Meet the AQUAPHOENIX partners advancing novel technologies to support sustainable production.

“The common way of looking at sludge is to consider it a problem. It’s a byproduct, and people don’t really want to see it. But if you can harvest some of the value from sludge — that’s potentially a game-changer.”

Magnus Holmefjord describes the untapped potential of sludge, a term describing the large volumes of faecal matter produced in open cage fish farms every day. Typically, this waste falls to the bottom below cages and is released into the surrounding water, threatening marine ecosystems with an overload of excess nutrients. 

But Holmefjord’s team, who is leading AQUAPHOENIX Work Package 1, has invented an alternative.

Holmefjord is the Manager for the LiftUP products within Framo Aquaculture, through an acquired leading manufacturer of pumping technology for the fish farming industry for 30 years. For decades, Framo has been developing innovative pumping systems to ships and offshore installations. In the last 10 years, they have expanded their offering with new Aquaculture products to purify and circulate water, keep fish healthy and increase efficiency in sites across the world. 

“The common way of looking at sludge is to consider it a problem. It’s a byproduct, and people don’t really want to see it. But if you can harvest some of the value from sludge — that’s potentially a game-changer.”

Magnus Holmefjord

Now Framo Aquaculture is working on novel technologies that salvage sludge before it reaches the seabed. “Our pumping technology extracts the sludge, brings it to the surface, dewaters it and prepares it for storage,” Holmefjord explains. It’s an effective solution that can be relatively easily integrated into existing infrastructure and adapted to individual needs.

Accelerating sludge collection with AQUAPHOENIX 

Sludge collection has already been piloted at several Norwegian salmon farms to validate its efficiency, security and ease of use. As part of the AQUAPHOENIX project, a four-year project funded by the European Union, Framo is continuing their rigorous testing efforts with the goal of bringing this technology to the wider world. Developing and demonstrating sludge collection is the central action of AQUAPHOENIX Work Package 1, led by Framo with support from partners in research, fish farming and waste management. 

From autumn 2025, the team will install sludge collection technology in active production sites in Norway and Finland. Their mission is to test sludge collection across regions, nations and seas; laying the groundwork for its enhancement and distribution on a much bigger scale. 

Working with local producers 

Installing the technology at active commercial fish farms is reinforcing the link between manufacturers and users, with aquaculture experts eager to test and report on how the technology works for them. 

“We don’t want to pollute our local community,” explains Ingebrigt Ølmheim, technical lead of Norwegian fish farming company Lingalaks, which is currently testing and providing feedback on sludge collection technology. “We want to have a sustainable business, economically and ecologically. So we are trying to collect the sludge in a sustainable manner.” 

Sludge collection is expected to have a positive environmental impact. As Holmefjord explains, “we are hoping that we can lay the foundation for gathering enough information to really understand what happens if we remove the sludge.” As part of AQUAPHOENIX Work Packages 2 and 3, research teams will measure and model the effects of sludge removal on surrounding ecosystems and assess its capacity to reduce emissions. 

“We don’t want to pollute our local community. We want to have a sustainable business, economically and ecologically. So we are trying to collect the sludge in a sustainable manner.”

Ingebrigt Ølmheim

From waste to resource

Aquaculture sludge contains nitrogen and phosphorus (N+P) that can pollute waters, threaten wildlife and curtail local industry when released in excessive amounts. But when harvested correctly, these elements are the key to understanding sludge as a resource.

“Sludge contains a lot of nutrients – phosphorus, nitrogen – that can have value further down the chain,” notes Holmefjord. 

Pumping, dewatering and storing sludge is only the first element of the AQUAPHOENIX action plan. Next, the sludge will be tested in a range of contexts including the production of sustainable assets like feed, fertiliser and renewable energy. 

From salvaging sludge to safeguard local ecosystems and support economic growth, to investigating its potential as a sustainable resource, the AQUAPHOENIX team is working to validate aquaculture waste as a circular resource and lead change on an international scale. Sludge collection technologies are one of the engines of this change: a key step towards reducing aquaculture emissions and realising a Zero Pollution Europe.