IMPACT OF GREATER USE OF DESALINATION

IMPACT OF GREATER USE OF DESALINATION

40.

Mr Seah Kian Peng asked the Minister for the Environment and Water Resources in light of increasing desalination in the coming years (a) what is the environmental impact of releasing brine into the ocean; (b) what is the experience of other countries with regard to releasing concentrated brine (or hyper-saline) over a long period of time; and (c) what is the impact on marine life and whether there is a risk of "dead zones" being created off Singapore island.

Assoc. Prof. Dr Yaacob Ibrahim: Brine, or concentrated saltwater, is a by-product of desalination. It may pose a threat to the marine ecosystem if improperly discharged to the sea. However, with available technologies, the brine discharge can be managed through internationally acceptable practices such that there is no long-term impact on the marine environment. These include discharging the brine at locations that would ensure better dilution, and using diffusers to reduce the brine concentration to ambient salinity levels.

For the existing SingSpring desalination plant in Tuas, the Tropical Marine Science Institute of NUS was engaged to carry out an environmental study before implementation of the plant to assess the impact of brine discharge on the marine environment. The consultants have been monitoring seawater quality data in the vicinity of the plant since it started operation in 2005, and have found that there has been no significant change in the levels of salinity of the seawater.

For the new desalination project which will also be sited at Tuas, PUB has engaged an independent consultant to carry out an environmental impact study. This study will recommend appropriate measures to mitigate any impact that may arise from the project implementation, and ensure that the marine water quality, ecology and coastal processes are protected and preserved.

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