SINGAPORE - The water quality in the Johor River has been assessed to be suitable for treatment, with PUB's Johor River Waterworks (JRWW) resuming treatment operations on Sunday (Oct 29) evening, PUB said in a statement on Monday.
"The water quality in Johor River at our plant's intake point is assessed to be suitable for treatment," said PUB. "JRWW has progressively resumed water supply to both Singapore and Johor."
PUB added that it will continue to monitor the raw water quality in the river closely, to ensure that it remains suitable for abstraction and treatment.
The national water agency had stopped treatment operations at 11am on Saturday due to high ammonia levels in the Johor River, disrupting water supply to Singapore and parts of Johor.
An ammonia level of 2.75 parts per million (ppm) - nearly double the Health Ministry's permitted level of 1.5ppm - was recorded late on Friday night.
Johor identified the source of the pollution on Sunday - a poultry farm and a factory in the Kota Tinggi district that converts manure into fertiliser.
The farm and factory were ordered to shut down.
Singapore draws up to 250 million gallons of raw water a day from the Johor River, under a 1962 agreement with Malaysia, which expires in 2061.
Malaysia's Ministry of Natural Resources and Environment asked for authorities such as the Kulai Municipal Council, Kulai Land and District Office and the Veterinary Services Department to "look into this matter seriously".
It also asked for the culprits to be blacklisted.
While PUB was able to increase production at its desalination plants and local waterworks to meet demand during the disruption, the agency stressed that "imported water from Malaysia remains an important source of water supply for Singapore".