West Cork students put green, slimy invaders to good use

The beautiful beaches of west County Cork have sadly, in the past few years, been overwhelmed by hordes of unwelcome, green, slimy, smelly, and noxious invaders.

No, this story has nothing to do with certain human visitors to the area. Rather this concerns the arrival of a green algae, ‘Sea Lettuce’ – or Ulva Lactuca to be precise.

It is not clear why the Sea Lettuce has arrived in rural Cork in such numbers. The two most popular theories are that it has something to do with global warming, as the Sea Lettuce is a creature that thrives in shallow, warm waters, or that it is linked to the pressure put on the local waste water plant.

It’s said that the Clonakilty waste treatment plant can’t cope with the increase in holiday homes in the area in recent times.  The inevitable result, it is argued, is the leaking of raw sewage into the ‘run off’ water, upon which the Sea Lettuce thrives.

But, no one knows the exact cause for sure.

Neither is west Cork alone, as this is a global problem now, one that has reared its head in places as far flung as Brittany, Beijing and Australia.


The local people in Cork have watched in horror as their beautiful beaches have disappeared under piles of green slime, sitting on top of the sand, emitting noxious gases and killing off some existing forms of sea life.

Enter three enterprising local Transition Year students, Muireasa Carroll, Mairéad Kingston and Denise Hurley, pictured above, from the Sacred Heart School in Clonakilty. They wanted to see if they could turn a ‘negative into a positive’.

They come up with a great idea. To harvest the Lettuce, use a machine to compress the water out of it, and mould it into briquettes for burning. They would then see if the Lettuce briquettes were a viable source of heat, and what gases they would emit.

They made their briquettes using a hydraulic pumping ramp. They tested the briquettes and found that they burned slightly longer than peat, with slightly less heat emitted. Also, the briquettes were ‘carbon neutral’. That meant that, unlike fossil fuel briquettes, they did not emit significant amounts of carbon dioxide ‘greenhouse gas’.

They appeared to have a viable ‘renewable fuel’ product that could be harvested cheaply from the strangled beaches in their locality. But, they didn’t stop there. They tested the briquettes for water concentration and found that even after they were compressed and moulded that the briquettes were made up of 25 per cent water.

If they can eliminate more water, they will have a product that burns even longer.

They also looked at the waste products from the burning of the briquettes – ash – to see if it could be put to good use. They found that the briquette ash was a very effective fertiliser and that it was also useful as a cleaning product to absorb stains.

All in all, it’s a brilliant idea, and reflects the move in recent years at the BT Young Scientist and Technology Exhibition discoveries that can help society to improve. Certainly, Sean Gallagher, one of the ‘Dragons’ from the RTE series ‘Dragons Den’ thought it was an excellent idea when he stopped to have a look while at the Show.

The girls are veterans of the Show and were also at the RDS in 2010. They impressed then too, enough to be offered a marketing course at TCD, which they took.

The Lettuce briquettes have been registered as a patent with the Irish patent office, and the girls want to develop the product into a business at some stage in the future.

They have also been invited to talk to local county councils, about their great idea.

But, for now, they have the Leaving Cert to attend to, but watch this space, this is an idea that could ‘find legs’ when the girls emerge from school in a few years time.

This project was the winner of the ‘Intel Students of Excellence Award, at the BT Young Scientist and Technology Exhibition 2011.

This article was first published in Science Spin (May-June 2011 Issue)

One comment

  1. Hi this is Muireasa from the article.Thanks for writing such a lovely article on our project. We have also gone on to win 4th place in the Environmental Management category in the Intel International Science and Engineering Fair which was held in May in Los Angeles.

Comments are closed.