The residue water from food industry works as an excellent fertilizer in land-based seaweed cultivation. It not only helps for seaweed to grow faster, but also helps for the protein content to multiply. This can help process water to advance from being a cost to become a resource in the food industry.
Does it seem possible for macroalgae such as sea lettuce to be at par source of protein among foods of the future the way soybean is placed today? Whilst protein content of seaweed is less than soybeans, the difference decreases with fertilizers.
A scientific article presented by researchers at Chalmers University of Technology and University of Gothenburg explains that process water from food production can serve as a superior fertilizer for cultivation of seaweed. The seaweed grew more than 60% faster, and the protein content increased by four times with the addition of process water.
Soybean contains 40% protein. The use of process water increases protein content of seaweed by more than 30%.
Meanwhile, it is known that algae grows better in the vicinity of fish farms in the sea due to nutrients it obtains from fish faeces that spreads in water. In the same way, process water from food industries id often rich in phosphorus and nitrogen.
For experimental purpose, the researchers examined four different types of seaweed and added process water from several different food producers – salmon farming, herring industry, shellfish processors, and manufacture of oat milk. The seaweed cultivation was added certain amount of process water with a controlled content of nitrogen. The results were analyzed after eight days.
Oat milk was included to achieve cultivation to be completely vegan. It turned out all different types of process water worked as well as fertilizer for seaweed.