Anatomy of a Lift Station
What's inside?
-a well (a hole in the ground usually) with an inlet
-2 pumps (sometimes more) connected into a discharge pipe
-a level sensing device (sometimes more than one)
-a control panel to turn the pumps on and off
At its simplest, when the level reaches a preset point - the activation point, or ON point, one pump is started. This empties the well under normal circumstances. When the well level reaches a lower preset point - the deactivation point, or OFF point, the pump is stopped.
In the next cycle, the other pump is started, evening out the wear between the two pumps. This is called alternation. If the running pump is faulted, or for any reason the level carries on rising, the other pump will be turned on.
Very simple, isn't it?
However, wastewater is pretty nasty stuff and anything that can go wrong, does go wrong, many times. Operations staff who look after lift stations will tell you about ragging of pumps, sticks in pumps, impellors of pumps falling off, cables burning out, level sensing devices giving false reading, pumps overheating..
The consequences are serious, as sewerage overflows create an environmental hazard - for example, children playing in the street come into contact with sewerage and get sick. It's a reality, so government regulatory bodies take sewerage spills extremely seriously, and often impose hefty fines on organizations who have spills.
