Exam Question
With reference to Vacuum Sewage Systems:
(a) Sketch & Describe a Vacuum sewage system.
(b) State the advantage of Vacuum sewage system.
(c) State the different causes of dropping vacuum.
Class 2 (2nd Engineer)
MEKG
📅 Mar 2020
Reference Answer
### (a) Sketch & Description of a Vacuum Sewage System
**Concept**
A vacuum sewage system utilizes a pressure differential to transport black water (sewage) from toilets and urinals to a central collection tank. The piping network is maintained under a constant vacuum (typically -0.4 to -0.6 bar). The sanitary fixtures themselves remain at atmospheric pressure until flushed. When a toilet is flushed, a discharge valve opens for a few seconds, and the higher atmospheric pressure in the bowl forcefully pushes the contents into the vacuum piping. The high-velocity slug of sewage, mixed with entrained air, travels through small-diameter pipes to the collection tank.
**Components & Operation**
**Concept**
A vacuum sewage system utilizes a pressure differential to transport black water (sewage) from toilets and urinals to a central collection tank. The piping network is maintained under a constant vacuum (typically -0.4 to -0.6 bar). The sanitary fixtures themselves remain at atmospheric pressure until flushed. When a toilet is flushed, a discharge valve opens for a few seconds, and the higher atmospheric pressure in the bowl forcefully pushes the contents into the vacuum piping. The high-velocity slug of sewage, mixed with entrained air, travels through small-diameter pipes to the collection tank.
**Components & Operation**
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