1.0 CIMCITY COMMISSION INFORMATION MEMORANDUM
ADMINISTRATIVE BRIEF FROM MARTHA TASKER June 13, 2022
UTILITIES DEPARTMENT
Portable Engine Generator Saves the Day During Extended Power Outage
During the wind storm of December 15th, 2021 the City's Wastewater Collection system
experienced multiple power outages. During the first few hours a total of thirty-eight out
of sixty sewer lift stations were without electric power and 24 hours later, seven lift
stations were without power. The Utilities Department purchased a 125 KVA portable
engine generator in 2018 at a cost of $71,000 to assist in this type of an emergency.
Staff utilized two gas powered pumps and the portable engine generator to keep the
wastewater flowing and ultimately preventing no sewage backups into citizen's buildings
or sewage overflows on to private property.
In some cases, power was restored before a high sewage level was reached at the lift
station. The portable generator was utilized at fourteen lift stations. This involved
traveling to a lift station and pumping the wastewater down and then traveling to the
next lift station and completing the same process. Some lift stations were operated on
the portable generator several times during the course of the loss of power event. In
addition, the portable generator provided power to a water booster station to fill a water
tower.
Sewage is collected in the sewer mains and flows downhill by gravity. At some point the
lines become so deep in the ground it is necessary to provide a sewer lift station to
pump the sewage up to a higher elevation where it will then flow by gravity to the next
sewer lift station. Each lift station has a minimum of two electric pumps that pump the
wastewater from a wet well, which temporarily stores the wastewater prior to pumping.
Prior to the portable generator, staff relied on the electric utility to restore power or
connected an engine driven pump to the lift station. Engine driven pumps require much
more time to connect and set up than the portable generator connection, and can't
easily be moved from station to station.
To connect the portable generator to a lift station, a disconnect switch and a large
electric "plug" are required. When staff arrives at the lift station, the cable from the
portable generator is connected to the "plug" and the switch operated to route the
portable generator power to the lift station.
The portable generator has been used
for power outages and times when the
electric utility company needs to work
on the power lines into a lift station.
The portable generator has also been
connected to submersible bypass
pumps. This setup was utilized during
replacement of a 24 inch sewer main at
Red Fox lane, thus saving the
manpower of staffing a manual bypass
pump 2417.