JOHOR BARU: The Johor government has shut down a chicken farm and fertiliser factory that caused pollution in the Johor River thrice since December 2016, forcing water treatment plants to shut down two of those times.
It said these were the only incidents where chicken manure fertiliser caused ammonia pollution in the river to this degree due to the sheer volume of product being processed.
Three water treatment plants, including PUB's Johor River Waterworks, were closed over the weekend due to the ammonia pollution in the Johor River.
The state says the 20-year-old farm and factory ignored prior warnings, leading to 360,000 account holders in Malaysia being affected as plants waited until ammonia levels were back to normal before starting up again.
Singapore's PUB said water supply in Singapore was not affected as the shortfall from the Johor waterworks was topped up from other sources, including desalination.
Water supply has since been restored for all the affected water treatment plants, including the Johor River Waterworks, which, according to the state government, was the least affected given its distance from the source of contamination.
"The water treatment plant for PUB is located at the furthest south end of Sungai Johor (Johor River), and Linggiu Dam, as the balancing dam, discharged 900 million litres for two days into Sungai Johor to dilute the level of contamination," said Johor executive councillor Hasni Mohammad at a news conference on Wednesday (Nov 1).
"(The Singapore plant) is located further downstream and is safer than the (Malaysian) plants."
Even though supply has been restored, the state says it is monitoring three other chicken farms located around the Johor River.
"I suppose with this incident authorities will have to look at their SOP and make good if there are any incidents here and there but the intention is to make sure incidents like this don't happen," said Mr Hasni.
To that end, Johor says it will no longer grant permits to companies to mine sand near water treatment plants, as this could cause a build-up of silt and muddy discharge, leading to polluted rivers.
It has also asked the state's water regulatory body to survey main areas around the Johor River and take strict action against any offenders.