Bypass Pumping Done Right & On Time for 25 MGD Trunkline Rehabilitation

Knoxville, TN – A 48-inch sewer trunkline needed to be relined and repaired. To clear the active rehabilitation zone, two bypass systems would be required for sewer flow control.

For the main bypass pumping station, Rain for Rent installed six 14-inch pumps to handle 25 MGD, three of the pumps were installed for back up. All six pumps were connected to the same 24-inch HDPE discharge line using a manifold system with a check valve for each pump. The system provided suction lift of 9-feet and moved the flow through approximately 1,330-feet of discharge pipe to the specified manhole. An additional bypass system of two 4-inch pumps, one installed for back up, was incorporated downline to integrate a 12-inch feeder line flow.

•Rain for Rent Engineering provided precise system designs and drawings.
•Bypass pumping system was equipped with dual float control for automatic start control and a remote monitor for high level notification.
•Prior to the project starting, the bypass systems underwent hydrostatic testing, and float control/remote monitoring system testing.
•To create a safer jobsite, each day a ‘Bypass Inspection Check List’ was reviewed, and JSAs (Job Safety Analysis) were performed.
•For the duration of the 2-month project, a minimum of one person remained on site at all times to provide 24/7 Pump Watch, inclusive of pump, sewer level, and discharge pipe monitoring, with pump refueling and maintenance as needed.

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