TO: Honorable Mayor & Members of the North Port Commission
FROM: Peter D. Lear, CPA, CGMA, City Manager
TITLE: Contract No. 2019-16 with Harn R/O Systems, Inc. for the Myakkahatchee Creek Water Treatment Plant Membrane Element Replacement Project.
Recommended Action
Award of Contract No. 2019-16 with Harn R/O Systems, Inc. for the Myakkahatchee Creek Water Treatment Plant Membrane Element Replacement Project in the amount of $ 222,348.44 with a contingency amount of $ 22,234 for a total project cost of $ 244,582.44.
Background Information
The reverse osmosis membranes at the water treatment plant experienced the loss of rejection beginning May 4, 2018. Loss of rejection means that the membranes are allowing to pass those constituents, primarily total dissolved solids (TDS), that they normally remove and typically is an indicator that the membranes are fouled or have failed. Harn R/O Systems, Inc, our quarterly service company for the system, was called and were onsite May 4, 2018. They inspected the reverse osmosis system and confirmed the loss of rejection. During a subsequent call with Harn R/O Systems, Inc., it was decided that the membranes would be probed to determine if all the membranes had failed or if the second stage might still be operational. The probing was performed on May 14, 2018 and confirmed that all the membranes had failed, likely due to exposure to an oxidant. The only proven method of restoration of membrane rejection is the replacement of the membranes. The membranes have been treating a source water with an increasing TDS and were approaching the end of their useful life.
Pursuant to the recommendation by Carollo Engineers, Utilities staff is recommending replacing the membranes with a hybrid array due to the five (5%) percent higher permeate water quality and the ability of the membranes to reject higher values of TDS. The specifications for the project identifies three Membrane Systems Suppliers (MSS) that could provide the se...
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