Ways to Recycle Seafood Waste Water

The seafood industry is incredibly water-hungry; it takes around 8,000 litres to prepare one ton of marinated mackerel, and up to 50,000 for a ton of peeled shrimp. But researchers at Chalmers University in Sweden have found new ways to reincorporate this waste water back into the food chain.

The research, dubbed Novaqua, found that the waste water contains high levels of valuable nutrients such as proteins, peptides, fats and micronutrients, which are being washed away into side streams during processing. Using a patented two-step process, the research team was able to recover up to 98% of the protein and 99% of the omega-3-rich fats from samples of water.

The resulting biomass of nutrient-dense liquid, which was shown to contain 66% protein and 25% fat, was then dehydrated. It can be used in a variety of ways – including as feed for salmon, a glaze for frozen fish that stops them becoming rancid, and a substance for microalgae-cultivation.

Project researcher Bita Forghani Targhi said: "I am quite positive of the fact that related industries, sooner or later, will be implementing these [recovery] techniques. With ever increasing awareness of the value of recycling nutrients, this facilitates industrial processes to adopt feasible approaches towards a circular economy."

Also seeking to rescue seafood waste is Norwegian cruise operator Hurtigruten Cruises. It recently announced that by 2021, six of its cruise ships will run on liquefied biogas – a natural, non-fossil fuel produced from organic fish waste.

For more on the sustainable use of waste in the food space, see Global Food Trends 2018-19: Sial Paris and Fighting the Rising Tide of Food Waste.