PETALING JAYA: A thick layer of black oil that was found at the entry point of the sewage treatment plant in Batang Kali was quickly cleaned up after it was detected, says Indah Water Konsortium Sdn Bhd (IWK).
"The oil cleaning work was completed at 5pm on Saturday (July 20) and the sewage treatment plant has returned to normal operations. (Also) the discharge of effluent is according to standards by the Department of Environment," it said in a statement on Sunday (July 22).
IWK said investigations by Selangor Water Management Authority (Luas) found that the black oil was believed to be disposed off from the industrial area around the IWK plant.
IWK said the maintenance team was informed that there were no traces of oil spill the day before and that the plant then continued operations as normal.
"The team received information from Luas on Saturday morning and had then rushed to the plant at 5am to check on its condition and the quality of the effluent that was released.
"Checks found that the concentrated oil which was black in colour had entered the plant at 7am yesterday. We then stopped releasing the effluent temporarily to ensure that the cleaning operation was swiftly conducted.
"In order to prevent any disruption to the quality of the effluent, isolation was done immediately to control the release of the final effluent to Sungai Liam," operations chief Mohd Taufik Salleh was quoted as saying.
IWK said traces of the oil that had entered the plant needed additional treatment which required the suction of the thick oil layers at its entrance as well as the usage of oxidisation materials to activate the biological process to reduce the smell of the treated effluent.
It also noted that more than 250kg of activated carbon was placed into the final effluent discharge channel to reduce the odour as was recommended by Luas and Air Selangor.
It added that IWK would be providing a 24-hour task force to monitor restricted materials to prevent the situation from recurring.
IWK also said Selangor Environment, Green Technology and Consumer Affairs committee chairman Hee Loy Sian visited the plant together with other state assemblyman, officials from the Department of Environment and relevant authorities.
Previously, it was reported that the Sungai Selangor Phase 1, Phase 2 and Phase 3 Water Treatment Plants and the Rantau Panjang Water Treatment Plant had to be shut down due to odour pollution in the Sungai Selangor raw water source.
Investigations showed the source of the odour pollution had originated from Sungai Liam in Batang Kali, Hulu Selangor.