Prawn shells can stop algal blooms in NI

A waste product from the local fishing industry can be used to remove blue-green algae from Lough Neagh, a committee of MLAs has been told.

Speaking at Stormont last Thursday, Harry Wick from the NI Fish Producers’ Organisation explained that the natural chemical chitosan can be obtained from prawn shells.

He said chitosan has binding properties which can be used to treat blue-green algae that has grown in Lough Neagh, as well as stop excess nutrients entering the waterbody in the first place.

“It has no observable negative effect on fish or wildlife. It completely biodegrades within three weeks.

“It’s already used for water treatment in the UK and as a natural fertiliser. From the regulatory side, it is completely safe,” Wick said.

His proposal is that shells from prawns which are harvested in the Irish Sea are refined in a purpose-built plant in NI and the product is initially used to address algal blooms in Lough Neagh.

“We have the raw material needed to treat Lough Neagh many times over.

“There are other challenges for water systems in NI and all over the UK and Europe.

“We could roll this out in other parts, and it could be something NI is known for,” he maintained.

When asked about the cost of the proposed project, Wick said it “depends on water quality analysis and how the solution is refined”.

“At this point, it is really difficult to give an exact cost. We need to get some boots on the ground in NI and start some work before that can be assessed accurately,” he said.

Examples

MLAs were told that the technology has been used in waterbodies in other parts of the world, with the most similar case to Lough Neagh being in Madison, Wisconsin, in the USA.

“There is a body of scientific evidence that proves this all works in theory. We also intend to expand on the case studies that show this works in practice,” Wick said.

Nathan Holloway from US-based firm Tidal Vision said a six-month trial could be carried out in NI, where water from the lough is treated with chitosan and filtered through sand.

“We estimate we could treat approximately one billion litres of water, return it right back to the lake and recycle the algae that we pull out of the water for compost,” he told MLAs.