FROM: Robert Thompson, General Manager
Originator: Mike Dorman, Director of Engineering
SUBJECT:
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DEWATERING CENTRIFUGE DIVERTER GATE IMPROVEMENTS AT PLANT NO. 1, PROJECT NO. FR1-0018
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GENERAL MANAGER'S RECOMMENDATION
recommendation
RECOMMENDATION: Recommend to the Board of Directors to:
A. Award a Construction Contract Agreement to Innovative Construction Solutions for Dewatering Centrifuge Diverter Gate Improvements at Plant No. 1, Project No. FR1-0018, for a total amount not to exceed $1,289,500; and
B. Approve a contingency of $193,425 (15%).
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BACKGROUND
The Orange County Sanitation District’s (OC San’s) Plant No. 1 Thickening and Dewatering (T&D) Building has three diverter gates installed. One diverter gate per dewatering centrifuge, at the basement level, to route unthickened solids, and wash water away from the centrifuge cake pump hopper to a drain during a centrifuge startup and shutdown.
RELEVANT STANDARDS
• Comply with California Public Contract Code Section 20103.8, award construction contract to lowest responsive, responsible bidder
• Maintain a proactive asset management program
PROBLEM
During a centrifuge startup, or water flushing cycle, water leaks through the closed diverter gate to the dewatering cake piston pump below, causing premature wear of the piston. Additionally, excessive water is being pumped to the biosolids cake silos creating a wetter cake, which impacts the truck loading process and biosolids handling costs.
PROPOSED SOLUTION
Award a construction contract to install three new water-tight diverter gates. The new diverter gates will be sourced from the same manufacturer that supplied the gates currently in use at Plant No. 2. These have demonstrated superior performance compared to the existing equipment at Plant No. 1.
TIMING CONCERNS
Delaying the project award increases the risk of premature wear or failure of the cake piston pumps.
RAMIFICATIONS OF NOT TAKING ACTION
If no action is taken, there is an increased risk of a cake piston pump failure, which would require the shutdown of the centrifuge and impact the biosolids handling capacity.
PRIOR COMMITTEE/BOARD ACTIONS
N/A
ADDITIONAL INFORMATION
OC San advertised Project No. FR1-0018 for bids on May 27, 2025, and received eight sealed bids on July 8, 2025. A summary of the bid opening follows:
|
Engineer’s Estimate
|
$ 1,750,000 |
|
Bidder |
Amount of Bid |
|
Innovative Construction Solutions |
$ 1,289,500 |
|
LEED Electric, Inc. |
$ 1,416,534 |
|
MMC |
$ 1,554,000 |
|
GSE Construction Company, Inc. |
$ 1,697,500 |
|
Myer and Sons |
$ 1,740,000 |
|
Tharsos, Inc. |
$ 1,786,000 |
|
Environmental Construction, Inc. |
$ 1,788,992 |
|
Minako |
$ 3,330,500 |
The bids were evaluated in accordance with OC San’s policies and procedures. A notice was sent to all bidders on July 24, 2025, informing them of OC San staff’s intent to recommend award of the Construction Contract to Innovative Construction Solutions.
Staff recommends awarding a Construction Contract to Innovative Construction Solutions, the lowest responsive and responsible bidder. This project requires modifications to existing equipment, some of which may only become accessible once work begins, and coordination with ongoing facility operations. To address potential unexpected conditions or operational delays, staff recommend including a 15% contingency."
CEQA
The project is exempt from CEQA, and a Notice of Exemption will be filed with the OC Clerk-Recorder and State Clearinghouse after the OC San's Board of Directors approval of the Purchase Order.
FINANCIAL CONSIDERATIONS
This request complies with the authority levels of OC San’s Purchasing Ordinance. This recommendation would be funded under the Repairs and Maintenance line item for the Operations and Maintenance Department (Budget FY 2025-26, Page 33) and the available funding is sufficient for this action.
ATTACHMENT
The following attachment(s) may be viewed on-line at the OC San website (www.ocsan.gov) with the complete agenda package:
• Construction Contract Agreement
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