Technical Visits
Shatin Sewage Treatment Works
Shatin Sewage Treatment Works (STSTW) is the largest secondary sewage treatment works in Hong Kong with a treatment capacity is 340,000 m3 per day. It occupies 28 hectares of land and was commissioned in 1982. The biological sewage treatment process adopted in STSTW is the activated sludge process named Modified Ludzack-Ettinger (MLE) process. It is a single-stage nitrogen removal process in which the aeration tank is configured into an initial anoxic zone and a subsequent aerobic zone.
Aerial View of STSTW
Highlights
"Co-settling" Sludge Treatment Scheme
A sludge treatment scheme on “co-settling” technology has been implemented in STSTW. The scheme: (i) provides a shortcut for a portion of the surplus activated sludge, after biological treatment, to return to the primary sedimentation tanks, which allows the processes of sedimentation, biological treatment and sludge thickening to be carried out simultaneously; (ii) improves primary sludge quality and hence reduces the sludge digestion time and facilities, and also the energy for heating the digesters. |
“Co-settling” Sludge Treatment Scheme in STSTW |
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Odour Management
In addition to routine odour monitoring, DSD has proactively developed a master odour management plan for STSTW, by which biological de-odourizers (bio-trickling filters) and activated carbon adsorbers are installed for treatment of odour from different areas and facilities. |
Bio-trickling Filter in STSTW
Activated Carbon Adsorber in STSTW
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Water Reclamation
- The reclaimed water produced by the water reclamation facilities at STSTW is used for irrigation of plants there and the dilution of chemicals required for sewage treatment processes.
- The facilities mainly contain three filtration parts, namely disc filters, ultra-filtration membranes and reverse osmosis (RO) membranes.
- The RO technology adopted can remove impurities, salts and viruses of size exceeding 1 nanometer.
Operation Flow Chart of the Water Reclamation Facilities in STSTW
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Landscape Beautification Works
Various landscape beautification works, in particular, green roof and vertical greening, have been commissioned at STSTW. The planting design concept is to use different types and species of plants to create different seasonal colourful palettes throughout the year to blend STSTW, physically and visually, into the surrounding natural environment. |
Green Roof in STSTW
Vertical Greening in STSTW |
