Drinking Water Safety Advisory Committee accepts investigation report for water quality incident at Queen’s Hill Estate and Shan Lai Court
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The Drinking Water Safety Advisory Committee (DWSAC) held a meeting today (July 16) and received a briefing from the Water Supplies Department (WSD) on the investigation report concerning the water quality incident at Queen’s Hill Estate and Shan Lai Court. The report aims to outline the WSD’s tracing work, covering the entire fresh water supply network from the Ping Che Fresh Water Service Reservoir to Queen’s Hill Estate and Shan Lai Court, along with related analysis and findings, and recommendations to prevent similar incidents in the future.
The Chairman of the DWSAC, Dr Chan Hon-fai, said that the tracing work conducted by the WSD was objective and scientific. The DWSAC agreed with the WSD’s findings that the black sediments in fresh water, identified as bituminous materials, originated from a 400-metre-long steel pipe with internal bituminous protective lining at Ping Che Road, which is located upstream in the water supply network of the estates. The sediments also contained a trace amount of blue fragments, which were identified as resin from the internal protective coating of valves in the water pipelines. A source of the fragments was found to be a valve located at Lung Ma Road outside the estates. The DWSAC agreed to continue the identification and replacement of any defective valves in the estates.
The DWSAC noted that the WSD and the Housing Department had carried out a series of joint operations over the past month. These included increasing the frequency of flushing the underground fresh water pipes along Lung Ma Road and within the estates, cleansing the water tanks in each building of the estates, and installing additional strainers at the existing filtering devices within the estates. The DWSAC noted that the prevailing water quality had resumed normal. The WSD will explore whether new technologies can be adopted to ensure effective cleansing and eliminate the possibility of sediment in the water pipes.
In addition, the DWSAC agreed with several recommendations put forward by the WSD, including the gradual replacement of steel water pipes with bituminous protective lining. This can effectively prevent recurrence of similar incidents in the future. The WSD reported to the DWSAC that it had promptly replaced a section of the underground water pipe with bituminous protective lining at Ping Che Road with an exposed temporary water pipe, and would strive to complete the laying of a new permanent underground water pipe by the end of this year.
The DWSAC asked the WSD to expedite the implementation of these improvement measures and expected the WSD to provide further progress updates before the end of this year.
The WSD’s investigation report (Chinese only) has been uploaded to the following website: www.wsd.gov.hk/en/core-businesses/water-quality/water-quality-incident/index.html