KUALA LUMPUR, Feb 23 — Air Selangor will source raw water from the downstream flow of a river and store it in ponds to ensure uninterrupted supply in the event of pollutants in its main intakes.

Air Selangor chief executive officer Suhaimi Kamaralzaman said that these ponds act as river security as the stored water could be used if river pollution occurs, the Star reported.

“If the river is polluted, we can shut the flow of the water into the ponds and draw water from there (the ponds) while the river is being cleaned up,” he said.

The method is currently being used at the Semenyih 2 and Labohan Dagang water treatment plants, with more plants being built to take advantage of the storage ponds.

Suhaimi explained that the previous method of building water treatment plants generally tapped upstream water as this was typically cleaner.

“The further downstream, the dirtier the water is typically, so these retaining ponds act as a pre-treatment process to ensure the water goes in the plant is clean,” he said.

He said water treatment plants built in the 1980s and 1990s were typically located upstream near mountains to allow waters to be pumped from there.

“This started to change as technology improved,” said Suhaimi, adding Air Selangor is one of the pioneers of the technology and was shortlisted for a Global Water Award in Spain last year.

He added that one of the criteria mentioned in Air Selangor's submission to the awards was the off-river water storage system.

“It impressed them (the awards organisers) a lot in terms of a newer way of approaching water treatment," he noted.

Suhaimi said Air Selangor would also be using the method to build the Rasau treatment plant downstream of the Klang River in the next four years.

“We are taking it downstream and putting the water in a series of eight ponds and then drawing water from that.

“The new plant is timely as there is a huge demand for water in Klang and we are trying to meet it by bringing the downstream water closer to where the demand is,” he said.

He added that while river pollution could not be completely stopped in the near future, the turnaround time would be faster with this method in the event of any water disruption.

He also said that they are working with overseas partners to make sure the needed technology is in place to cater for the treatment processing required.

“Among the methods being looked at is pre-ozonation, which is technically using ozone to disinfect the water before it is drawn into the plant.

“The dirtier the water, the more costly the technology will be, but it needs to be done and we will do it,” he said.