Potential answer to scourge of red tide in UAE

After waves of marine algae hit the UAE with a devastating impact last year, scientists have been trying to come up with a way to protect the country's waters from another siege of "red tide".

Powered by automated translation

ABU DHABI // After waves of marine algae hit the UAE with a devastating impact last year, scientists have been trying to come up with a way to protect the country's waters from another siege of "red tide". And they believe they could have a solution. At a cost of Dh8 million (US$2.16m), it doesn't come cheap. But, if it works, it would be worth every dirham. With the blight thought to have cost desalination plants hundreds of thousands of dirhams.
The answer, they hope, will lie with a system used to clean ballast water on ships, a technology being adapted to work on land. Testing of a pilot programme will begin this summer off the shores of Abu Dhabi to see whether the system, developed in Japan, can be used as a contingency tool to limit the damage of harmful algal blooms. The idea was conceived in October last year as the east coast was recovering from possibly the worst algal bloom event in the country's history.
Developed by Hitachi Plant Technologies and Mitsubishi Heavy Industries, the method was showcased to officials from the Environment Agency-Abu Dhabi (EAD) who were on an official visit to Japan. "It could be an answer," said Dr Thabit Zahran al Abdessalaam, EAD's director of biodiversity. In the event of another outbreak of red tide of the same magnitude, the UAE needs to protect its desalination plants, he said.
The country depends on desalination plants for more than 90 per cent of its domestic water supply. The algal bloom from August 2008 through March 2009, which hit Fujairah and Khor Fakkan particularly severely, is commonly called red tide because it turns water a dark blood reed. It caused disruptions in desalination plants on the east coast, with production in some plants decreasing by up to 40 per cent due to equipment failures.
The red tide is estimated to have caused losses of US$100,000 a day for industry, according to the Abu Dhabi Water Resources Master Plan. It also killed hundreds of tonnes of fish, whose rotting corpses fouled beaches and hurt tourism, and suffocated significant portions of coral reefs. In order to keep balanced, ships take up a certain amount of ballast water at the start of a voyage. International regulations require vessels to treat that water before discharging it back at sea at the end of a journey. This is done so that bacteria, algae and marine creatures inhabiting a certain area are not spread to other parts of the ocean.
EAD is investing in adapting the system for a land-based device. A machine capable of treating 400 tonnes of water per hour will be tested in Abu Dhabi in the summer. "The technology has been used in ships for a few years but this application has never been tried anywhere" on land, Dr al Abdessalaam said. The system works with a process called "flocculation", in which chemicals are used to clump together bacteria, algae, sediment and other pollutants, which then fall and settle on the bottom.
The intake of water is also treated with magnetic power which mixes with the lumps of pollutants. The liquid is then run through a separator which extracts the flocks from the rest of the liquid. The flocks, which have the consistency of sludge, are removed. EAD will be testing the pilot device at a yet-to-be-determined location off the shores of Mussafah where there are high concentrations of algae in the seawater in summer.
The device is expected to arrive in Abu Dhabi by the beginning of July. It will be tested over a year to determine its effectiveness. René Hoeijmakers, a director at Royal Haskoning, an international engineering and environmental consultancy which has an office in Dubai, said that one issue that should be considered is cost. Both ballast water and desalination plant intake represent challenges, he said. A ballast water-treatment system has to be very compact, at no more than 2,000 cubic metres per hour, but a system for a desalination plant needs to be capable of handling 50,000 cubic metres per hour.
vtodorova@thenational.ae