(b) Advantages of a Vacuum Sewage System:

• The vacuum sewage system uses 85–90% less water for flushing compared to conventional systems, requiring very little flushing water.
• Toilets can be positioned more flexibly, including below the level of the holding tank, which is not feasible with gravity-fed systems.
• The system uses smaller diameter piping, reducing material and space requirements.
• The reduced water usage contributes to overall water conservation, making the system environmentally friendly.

• If the pump is pumping foam instead of liquid, this will be evident due to severe vibration. Add water to the tank and try again. If adding water does not help, reduce the level of foam by pouring antifoam agent into the tank (1 cup per 2 cubic metres of foam and sewage).
• Check that shut-off valves are fully open and not clogged.
• If the direction of rotation of the pump is wrong, change wiring accordingly.
• Close the valves that isolate the collecting unit from the piping system and start the pump again. If vacuum now builds up, there must be a leak in the piping system.