Singapore's PUB draws curtain on algae
Singapore's national water agency PUB has for the first time installed silt curtains at the waters off Tuaspring and Singspring desalination plants, to protect them from damaging fouling of their reverse osmosis membranes by mounting levels of algae in the water.PUB said it was installing the silt curtains after it had noticed a slight increase in levels of algae in the seawater around that area. The agency said would monitor the situation and, if necessary, the silt curtains will stay on beyond April 20. An algal bloom in the East Johor Strait in recent weeks killed some 600 tonnes of fish at fish farms. Such blooms can be triggered by weather changes, a higher concentration of nutrients in the seawater and poor water exchange between high and low tides.
Silt curtains, which drop to the seabed, can help keep out silt particles or other materials. Desalinated water is one of Singapore's four national souces of potable water and the two plants currently can meet up to 25% of the country's water demand.
Director of Nanyang Technological University's Maritime Research Centre, Tan Soon Keat said the silt curtains would be able to block out primarily suspended solids and, to a certain degree, oil slicks.
He said low-quality intake water may need additional pre-treatment processes that would incur additional cost, added Tan He explained that during dry weather there is more land-based washoff when sudden rain falls on the hard. dry land. He said that there may be elevated levels of phosphorus and nitrate in the runoff. Installing silt curtains, he said, was good practice, as it can buy time for the desalination plant to respond.