Sha Tin Sewage Treatment Works (STSTW) is the largest secondary sewage treatment works in Hong Kong. It occupies 28 hectares of land and serves a population of about 630,000 in Sha Tin and Ma On Shan Districts, which produce 250,000m³ of sewage per day.

STSTW was commissioned in 1982. To meet the continuous population growth in Sha Tin and Ma On Shan, the STSTW Extension Works were progressively. The treatment capacity of the STSTW was increased to 340,000m³ per day after the Extension Works.

Historical Photos of Existing STSTW

Sewage Catchment Areas in Sha Tin

There are six sewage pumping stations for transferring the sewage collected via the existing underground sewerage network within the six sewage catchment areas in Sha Tin district to the STSTW for centralised treatment.

Effluent Export Route

At present, the treated effluent from the STSTW is pumped to the effluent export tunnel starting at Nui Po Shan of A Kung Kok, and then transported to Kai Tak River in Wong Tai Sin for discharge. This arrangement can make use of the flushing effect by the treated, clean effluent from the STSTW, and hence improve the water quality and environment of the Kai Tak River.