O.N. Stevens Water Treatment Plant Raw Water Influent & Chemical Facilities Improvements

Photos

_{Existing Raw Water Intake Infrastructure to be Upgraded}

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Summary

The existing raw water piping configuration and Raw Water Junction Box at the O.N. Stevens Water Treatment Plant limit the hydraulic capacity to less than treatment capacity of the Plant.  In addition, existing piping makes it difficult to split incoming water flow between the four treatment trains. This project proposes to eliminate all hydraulic constrictions in the front-end piping, which allows raw water to be routed through the pre-sedimentation basin, and allows a passive flow split between the four treatment trains. The project will assure water demand for the City with future population projects and industries growth.

Construction is expected to start by the end of 2020 and should be complete in 2023.

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Project Scope

The project scope for the Chemical Facilities Improvements work components consist of the following major elements.

Chemical Storage Improvements (Designed for 200 MGD plant capacity.)

• Additional fiberglass bulk Alum storage tanks
• Replacement of three polymer storage tanks with new tanks for storage of liquid ammonium sulfate (LAS), and two new fiberglass polymer storage tanks
• Additional bulk and day tank storage tanks for Caustic Improvements
   

Chemical Feed Improvements (Designed for 200 MGD plant capacity.)

• New flow‐paced metering pumps for feeding alum, cationic polymer, LAS and caustic (Additive Alternate Only).
• New chemical diffusers, or direct injection and pumped diffusion flash mixing equipment for the introduction of alum, polymer,  LAS, and caustic into the water treatment train.
• Chemical injection point modifications/relocations to accommodate new raw water influent improvements.
• PLC replacement/upgrades for LAS, polymer, alum, and including integration.
   

Sedimentation Basin Hydraulic Improvements

This project includes installation of a full width and depth baffle wall replacing the distribution channels at the head of each sedimentation basin to improve flow distribution across each basin and increase baffling factors and concentration time.  These improvements are designed for an ultimate plant flow rate of 200 MGD.

Caustic Feed Improvements (Additive Alternate #1 ONLY)

• New 7,000-gallon Caustic Day Tank
• New 15,000-gallon Caustic Bulk Tank
• New Caustic Transfer Pump
• New Caustic metering pumps skid with 6 total pumps
• New containment area for all of the above.
   

Sodium Permanganate

• Proposed sodium permanganate injection point for algae control

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Reports

Project Location Presentation