Wastewater Treatment Process

Sha Tau Kok Sewage Treatment Works (STKSTW) provides secondary level treatment to sewage collected from the Sha Tau Kok areas.

Wastewater Treatment Process in STKSTW

Preliminary Treatment / Screening

Includes screening and removal of grit. Solids larger than 6 mm in diameter are removed from the sewage.

Primary Treatment

Includes screening, removal of grit and a sedimentation process. Solid waste and settleable suspended solids are removed from the sewage. Removal efficiency for Total Suspended Solids (TSS) is about 70% and Biochemical Oxygen Demand (BOD) is about 30% by this process.

Secondary Treatment

The sewage is purified by means of a biological treatment process after the primary treatment. The organic matter and nutrient in the settled sewage are decomposed by micro-organisms in the biological treatment process. Treated effluent from this process meets 30mg/L TSS and 20mg/L Biochemical Oxygen Demand standard.