Could experts have a solution to toxic algae?

Experts are testing out a new method that could see a way to tackle blue-green algae blooms.

The toxic algae is actually cyanobacteria rather than a true algae and can increase dramatically in heat, making people and animals sick when ingested.

Dr Sanjay Nagarajan, from the Institute for Sustainability and Climate Change at the University of Bath, took his child to the Warminster Pleasure Grounds in Wiltshire when he saw the lake there closed because of the bloom.

He and colleagues have since created a machine to help eliminate it from the water which he hopes he can make bigger and loan to councils.

From January to October this year alone there have been more than 168,000 visits to the park in Warminster.

People would usually be able to take boats out onto the lake and an active model boat club is in the area.

However, while it tends to die off in wintry weather, the algae has been causing problems over summers and this year it has been closed to activities for several months, with warning signs up round it.

"Every year it gets worse and worse with climate change," said Kevin Whitehorn, the estates manager for Warminster Town Council.

"Water levels in the lake have gone down which meant the blue-green algae has grown even more than it has done in the previous years," he added.

Nagarajan, a chemical engineer, visited the park with his child and emailed the council saying he wanted to test something.

His colleague, Dr Madhubalaji Chegu Krishnamurthi, has been studying algae for a decade and said "there many good algae as well as bad algae".

"Whenever the bad algae grows more, because of the nutrients in the lakes, it will release the various toxins that are very harmful for humans."

Nagarajan, with colleagues and a PhD student, have put together a machine with a reactor that uses bubbles to get rid of the algae. The type of reactor is not new, but its use like this is.

As with many new inventions, in order to get the water in and out of the reactor, they have had to improvise. This devices uses a generator and equipment usually used for home beer brewing.

A small box at the side does a lot of the work - Nagarajan explained that it is the reactor.

"If you take a small drinks can, fill it up with some water, heat it up and then invert it into an ice bath, it gets crushed. That's exactly what happens inside the reactor and we call it cavitation.

"Whenever we are able to manipulate the conditions to produce these cavitation bubbles, these bubbles will actually be crushed or imploding.

"Once the implosion happens those effects will help in destroying the bloom."

Nagarajan said they have had positive results: "We've seen up to 20% degradation in terms of toxins and we've also seen a lot of the algal cells being destroyed because of the effect of cavitation."

The next stage is to get their results published and apply for funding to create a bigger machine they can loan out to councils.

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