KUALA LUMPUR, Dec 22 — The Sungai Semenyih Water Treatment Plant is to remain non-operational until further notice as restoration work is still ongoing following an odour pollution incident at Sungai Semenyih on Friday.

In a statement, Air Selangor Sdn Bhd (Air Selangor) corporate communications chief Abdul Halem Mat Som confirmed that Indah Water Consortium Sdn Bhd and related agencies such as Lembaga Urus Air Selangor (Luas) were actively carrying out cleaning work.

"Manhole cleaning work near the sewage treatment plant to suck out the contaminating effluent is ongoing. Activated carbon damping has also been implemented to reduce the impact of odour pollution in the Semenyih River.

"As of 6.30am today, the odour pollution reading is recorded at 3-tonne level. Therefore, the water treatment plant is still unable to operate until the reading reaches 0 tonne level which is non-existent,” he said.

Meanwhile, the National Water Services Commission (SPAN) also confirmed the incident was due to illegal waste disposal in the form of contaminants into sewage manholes by unscrupulous parties following initial site visit investigations.

"SPAN views this act seriously as it is unacceptable. The perpetrators, soon to be identified, will see action taken against them under the Water Services Industry Act.

"Following the completion of our investigations, the case will be referred to the Attorney General’s Chambers for further action,” it said.

Yesterday, Air Selangor said the large-scale work stoppage would result in 348 areas with 328,957 consumer accounts in Petaling, Hulu Langat, Kuala Langat and Sepang experiencing unscheduled water supply disruption following the pollution.

In another development, he also said the Bukit Tampoi plant had also been affected and shut down since yesterday evening, leaving the water supply of 366 areas and 336,930 consumer accounts affected in addition to yesterday’s figure.

He said Air Selangor is expecting the recovery period for the supply disruption to take some time, thus it has provided emergency water supply assistance at local service centres with tanker trucks dispatched to affected areas with priority given to users, critical premises and emergencies including hospitals.

"The public are urged to refer to the Air Selangor mobile app, Facebook and Air Selangor Instagram, or our website for information which will be updated from time to time,” he added.