Drainage Services Department (DSD) successfully convened “HATS2A Hydraulics and Process Forum” on 23 May 2014 at Stonecutters Island Sewage Treatment Works (SCISTW).

Since the construction of HATS 2A project started in 2009, there had been continuous changes in population projections, development scenarios, environmental conditions and technological innovations.  The Forum reviewed the hydraulics and process design of the project so that fine adjustments could be made to enhance the design to meet the continuing changes and to facilitate the project commissioning in 2015.  The Forum shared the wisdom of the DSD project team and operational staff, the consultants, and the researchers actively engaged in the project planning and investigations.  There were more than 130 participants joining the Forum.

Topics that addressed at the Forum included:

• System hydraulics of the Sewage Conveyance Systems, the Preliminary Treatment Works and SCISTW;
• Hydro-mechanical design and operation of the existing and new main sewage pumping stations and their interconnecting tunnel;
• Hydraulic and process design of the chemically enhanced primary sedimentation tanks;
• Mitigation measures for the sewage septicity problem: corrosion protection, odour management and guarding of operators’ safety;
• Sludge dewatering, transport and disposal processes;
• Instrumentation system control, automation and system integration of HATS Stage 1 and Stage 2A;
• Effluent disinfection before marine disposal; and
• Environmental legislation compliance issues.