7.0 Contingency Operation
The lift station has been designed with two equally-sized pumps for full redundancy, each able to handle full-flow capacity. A backup, natural-gas fed generator will be installed with the proposed lift station, which will allow for continuous operation on backup power. Colorado Springs Utilities will be supply natural gas to the site. Primary electrical power to the site will be provide by the City of Fountain.
In addition to redundancy and backup power generation, emergency storage will be constructed to provide a minimum of 8 hours of storage time (maximum 8-hr flow) in the event of a failure. Maximum flow was determined using a diurnal hydrograph provided by the district. This value exceeds CDPHE requirements for overflow storage equal to eight (8) hours of average daily flow. Auxiliary storage will be provided with the available storage volume in the wet well along with an approximately 20,000-gallon storage tank buried adjacent to the wet well. An overflow line will discharge from the wet well to the storage tank in the event of pump failure. A drain line on the auxiliary storage tank will be installed with an isolation valve to allow the storage tank to be hydraulically connected to the wet well. The storage tank will also be equipped with at least one 24-inch riser pipe to allow access from the surface. In the event of a failure, the force main will be plumbed to allow for bypassing lift station pumps using independently powered pumping equipment. A vac truck will also be able to access either the wet well or the storage tank to pump out stored wastewater.
The lift station will be equipped with a SCADA (Supervisory Control and Data Acquisition) system which will monitor and transmit operational information to operations office. That information shall include but is not necessarily limited to:
- Failure of the pumps to start or stop
- Wet well levels
- High level alarms triggered by backup float switches
- Loss of power
- Pump run times
- Pump On/Off Status
- Flow Rate
The SCADA system will include a telephone dialer that calls out to operations staff notifying them of the alarm. The operators then may take appropriate action regarding the nature of the alarm.
The operator response time to an emergency situation would most likely be less than 1 hour, especially considering the automatic safeguards in place.