FROM: James D. Herberg, General Manager
Originator: Rob Thompson, Assistant General Manager
SUBJECT:
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PLANT NO. 2 TRICKLING FILTER PUMP STATION VARIABLE FREQUENCY DRIVE REPLACEMENT
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GENERAL MANAGER'S RECOMMENDATION
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RECOMMENDATION:
A. Approve a Service Contract with Baker Electric, Inc. for Plant No. 2 Trickling Filter Pump Station Variable Frequency Drive Replacement, per Specification S-2021-1273BD, for a total amount not to exceed $191,290; and
B. Approve a contingency of $19,129 (10%).
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BACKGROUND
The Orange County Sanitation District (OC San) Plant No. 2 secondary treatment process uses three trickling filters for water treatment. Each of the three trickling filters has a pair of Variable Frequency Drive (VFD) controlled pumps to lift flow from the primary basins up to the filter beds. Each pump is rated at 36.4 MGD and five of six pumps are required to deliver peak flow. The existing six VFDs are obsolete and no longer supported by the manufacturer.
RELEVANT STANDARDS
* Protect OC San assets
* 24/7/365 treatment plant reliability
* Maintain a proactive asset management program
PROBLEM
The existing Plant No. 2 Trickling Filter Pump Station is necessary to meet OC San effluent discharge requirements. The VFDs that drive the pumps for this station were declared obsolete by the manufacturer. This means that spare parts and support services are no longer available for these units. One unit has already failed and is in the process of being retrofitted similar to the proposed solution below.
PROPOSED SOLUTION
Staff recommends replacing Trickling Filter Pump Station VFD internal components with new original equipment manufacturers upgrade kits. This will result in essentially new, supported units, while reusing the old cabinets, conduits, controls, and wiring. The upgraded VFDs will provide more reliable operation and will reduce risk in emergency conditions during peak wet weather flow events...
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