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A screenshot of Pernille Marianne Carlson presenting her lecture at the Lice Conference 2021.
A screenshot of Pernille Marianne Carlson presenting her lecture at the Lice Conference 2021.

A technological-chemical method of neutralising hydrogen peroxide in water used in salmon bath treatments has been developed by the Norwegian Institute for Water Research (NIVA).

NIVA researcher Dr Pernilla Marianne Carlson told the Lice Conference 2021 that experiments have shown that a standard treatment solution with hydrogen peroxide for use against salmon lice must be diluted 11,000 times so that the solution is no longer dangerous for what are called non-target organisms, ie, organisms you do not want to affect. Both algae and crustaceans such as shrimp and krill have been shown to be sensitive.

Niva has, among other things, tested several different types of chemical that can be added to the bath water. One, known as Component A, has been shown to meet many requirements, although one downside is that it is sensitive to temperature.

Removes oxygen

“Another disadvantage is that it also removes the oxygen in the water. The advantage is that it removes hydrogen peroxide quickly and that other water parameters, apart from oxygen, stay well,” said Carlson.

She pointed out that it is undesirable to release oxygen-free water, so it is something that had to be solved before the method is fully developed. NIVA has applied for a patent for the method.

Graphic showing the development in the concentration of H2O2, pH and O2 after use of a chemical reducing agent. Table of various substances that have been tested to neutralise H2O2 before discharge to sea. Taken from Pernille Marianne Carlson's lecture at the Lice Conference 2021. *Rentsjøvan = seawater. H202 tilsatt = H202 added. Click on image to enlarge.
Graphic showing the development in the concentration of H2O2, pH and O2 after use of a chemical reducing agent. Table of various substances that have been tested to neutralise H2O2 before discharge to sea. Taken from Pernille Marianne Carlson's lecture at the Lice Conference 2021. *Rentsjøvan = seawater. H202 tilsatt = H202 added. Click on image to enlarge.
The area exposed to potentially harmful concentrations of H2O2 with (left) and without reduction of the treatment concentration before discharge to sea. Taken from Pernille Marianne Carlson's lecture at the Lice Conference 2021. Click on image to enlarge.
The area exposed to potentially harmful concentrations of H2O2 with (left) and without reduction of the treatment concentration before discharge to sea. Taken from Pernille Marianne Carlson's lecture at the Lice Conference 2021. Click on image to enlarge.