Dye Test Inspection for Submarine Outfalls
Dye Test Inspection for Submarine Outfalls
Submarine outfalls are used for discharging treated sewage from DSD sewage treatment plants into the sea. These submarine outfalls are located in various water areas across Hong Kong.
Each year, every submarine outfall is scheduled to be tested once to ensure the integrity of the submarine outfalls for discharging effluent from the DSD sewage treatment plants. The dye test would generate a fluorescent green colour patch at the observed area, and it is the result of testing as the green dye emerges from the submarine outfall.
The dye used is a non-toxic dye and is harmless to the marine environment. The tidal current will disperse it rapidly.
Schedule of Dye Test Inspection of Submarine Outfalls
|
Position |
Location |
Date of test |
Expected time of observation of dye at outfall point |
|
1 |
To Kwa Wan PTW |
10-Dec-2025 |
10:15 – 10:45 |
|
2 |
North Point PTW |
10-Dec-2025 |
10:20 – 10:50 |
|
3 |
Kwun Tong PTW |
10-Dec-2025 |
10:25 – 10:55 |
|
4 |
Tsueng Kwan O PTW |
10-Dec-2025 |
10:30 – 11:00 |
|
5 |
Stanley STW |
10-Dec-2025 |
10:35 – 11:05 |
|
6 |
Aberdeen PTW |
10-Dec-2025 |
10:40 – 11:10 |
|
7 |
Central PTW |
10-Dec-2025 |
10:45 – 11:15 |
|
8 |
Wan Chai East PTW |
10-Dec-2025 |
10:50 – 11:20 |
Outfalls Location on 10 December 2025 Schedule
Schedule of Dye Test Inspection of Submarine Outfalls
|
Position |
Location |
Date of test |
Dosing time |
|
1 |
Sha Tin STW, East Pipe |
19-Dec-2025 |
09:30 |
|
2 |
Sha Tin STW, West Pipe |
19-Dec-2025 |
14:00 |
Outfalls Location for 19 December 2025 Schedule
Schedule of Dye Test Inspection of Submarine Outfalls
|
Position |
Location |
Date of test |
Dosing time |
|
3 |
Pillar Point STW, Emergency Bypass Pipe |
6-Jan-2026 |
13:00 |
Outfalls Location for 6 January 2026 Schedule
Schedule of Dye Test Inspection of Submarine Outfalls
|
Position |
Location |
Date of test |
Dosing time |
|
4 |
Pillar Point STW, B Pipe |
16-Jan-2026 |
13:00 |
|
5 |
Sham Tseng STW, Outfall |
16-Jan-2026 |
13:00 |
Outfalls Location for 16 January 2026 Schedule
