Submitted By: Hector Colon
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Presentation By: Sean Lanier
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Department: Engineering
FORMAL TITLE:
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Amendment No. 5 to the Professional Design Services Agreement for Water Treatment Plant No. 2 with Kimley-Horn and Associates, Inc.
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OCALA’S RELEVANT STRATEGIC GOALS:
Operational Excellence, Quality of Place
PROOF OF PUBLICATION:
N/A
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BACKGROUND:
The original Water Treatment Plant No.2 (WTP-2) design scope, now approximately 90 percent complete, was based on constructing a water treatment plant (WTP) that would blend water from the Upper Floridan Aquifer (UFA) with the Lower Floridan Aquifer (LFA) to produce nine million gallons per day (MGD). However, during coordination with the City’s Construction Manager at Risk (CMAR), estimated construction costs have escalated dramatically from the pre-design estimate of $72 million to $265 million based on the 90 percent design, rendering the project financially unfeasible.
Following discussions with the St. Johns River Water Management District, the team initiated a value engineering and cost-saving strategy to phase the construction of the plant. The plan is to postpone the LFA phase, which utilizes membrane filtration as the treatment method and is responsible for most of the escalation in construction costs. As a result, the project scope has been revised to prioritize the design and construction of a 13.5 MGD Upper Floridan Aquifer (UFA) facility for the first phase of construction, thereby meeting the City’s immediate water supply needs. Additionally, the team will evaluate electrocoagulation (EC) as an alternative treatment method to membrane filtration for the LFA. Most of the existing LFA design will remain usable even if EC is eventually chosen as the treatment method for the LFA phase.
Electrocoagulation is an advanced water treatment process that utilizes electricity to remove contaminants from water. At its core, the process involves passing an electric current through water containing suspended, emulsified, or dissolved pollutants. This electric current generates coagulating agents in situ, which then interact with the contaminants, forming larger particles that can be easily separated from the water.
The Electrocoagulation process begins with the dissolution of metal electrodes, typically made of iron or aluminum, when an electric current is applied. This reaction produces metal ions that serve as coagulating agents. The metal ions react with hydroxyl ions in the water to form metal hydroxides. These hydroxides are highly effective at adsorbing contaminants and forming larger, more easily removable particles. The metal hydroxides destabilize suspended particles in the water by neutralizing their electrical charges. This destabilization allows the particles to come together and form larger aggregates. As the destabilized particles collide, they form larger flocs. These flocs can then be easily removed from the water through sedimentation, flotation, or filtration.
FINDINGS AND CONCLUSIONS:
This amendment is a “no cost” change to amend the scope of work and extend the contract expiration date by 365 days to complete the project. The design scope of WTP-2 will be amended to include the tasks necessary for completing a 13.5 MGD UFA Water Treatment Plant design, which allows for the phased implementation of the LFA portion of the plant in the future. The design scope will also include the evaluation of electrocoagulation (EC) for the treatment of the LFA raw water at WTP-2 and the UFA raw water at WTP-1. Completion of the design for the LFA phase will be put on hold until the evaluation of the EC treatment method has been completed.
Staff recommends approval of Amendment No. 5 with Kimley-Horn and Associates, Inc.
FISCAL IMPACT:
Funding for Amendment No. 5 was encumbered under the original contract in account string 455-020-302-536-53-31010. Amendment No. 5 will use the remaining contract funds. No additional funds are required.
PROCUREMENT REVIEW:
These services were procured in compliance with the City’s Procurement Policy.
LEGAL REVIEW:
This Agreement will be reviewed and approved for form and legality by City Attorney, William E. Sexton.
ALTERNATIVE:
• Approve with Changes
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• Deny