HomeMy WebLinkAbout7.b. Well 7 Operational Improvements
EXECUTIVE SUMMARY
Utility Commission Meeting: June 28, 2021
AGENDA SECTION:
AGENDA ITEM: Well 7 Operational Improvements
New Business
PREPARED BY: Brian Erickson, P.E. Director of Public Works
AGENDA NO. 7.b.
/ City Engineer
ATTACHMENTS: None APPROVED BY: BLE
RECOMMENDED ACTION: None, informational only
BACKGROUND
The City of Rosemount shut down usage of Well 7, near Chippendale Tower due to an elevated
manganese concentration in the water. This shut down was performed as part of a coordinated effort
between the Minnesota Department of Health (MDH) and the City of Rosemount. At the time this was
seen as the best solution until additional information was available.
DISCUSSION
Recently the MDH took sample and has been working with city staff to monitor the manganese in the
various wells. As a result, the MDH has provided an option for being able to restart and use Well 7 as
long as another well is on line at the same time. This will provide for a blending effort in the water system.
There is an inability to vary the pumping rate in Well 7 due to the age of equipment. Staff has contacted
local vendors that have the ability to upgrade the equipment in the well to allow a variable pumping rate.
Additionally, the replacement of the existing aged pump motor was priced as well. Ultimately, these
upgrades will cost approximately $40,000 and allow the well to resume some pumping.
The recommended upgrades include:
Variable Frequency Drive (VFD) which will allow the pump to run at different speeds in order to
meet the MDH’s recommended blending rates. - $18,000
Pump motor replacement for the exising aged pump. Staff did review the possibility of installing a
‘filter’ which would have allowed the old motor to be driven at various rates. However, that cost
was more than half the cost of a new motor ($6,500, filter versus $12,500, new motor). Therefore,
staff is planning to replace the motor.
Labor costs are estimated between $8,000 and $10,000.
RECOMMENDED ACTION
None, informational only.
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