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1 RiversideCA.gov
BID NO. 7935
CHLORINE CONTACT BASE 2 (CCB2) FREE
CHLORINE MODIFICATIONS AT RIVERSIDE
REGIONAL WATER QUALITY CONTROL PLANT
City Council
February 28, 2023
PUBLIC WORKS DEPARTMENT- SEWER DIVISION
RiversideCA.gov
2 • The Wastewater Division is responsible for the collection, conveyance, and treatment of wastewat er generated within the City of Riverside and the Communities Service Districts of Edgemont, Jurupa, Rubidoux, and the unincorporated community of Highgrove.
• Sewage treatment is performed at Riverside’s Regional Water Quality Control Plant (RWQCP), which provides primary, secondary, and tertiary treatment which has a hydraulic rating capacity of 46 million gallons per day (MGD). • Discharge of treated effluent from RW QCP is mandated by the City’s National Pollutant Discharge Elim ination System (NPDES) permit as authorized by the Clean Water Act, issued by the California Regional Water Quality Control Board (RWQCB), Santa Ana Region, and Title 22 (State of California Water Recycling Criteria) for disinfected tertiary recycled water.
BACKGROUND
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3 The RWQCP operates as two individual plants:
a. Plant 1, Membrane Bioreators (MBR) Treatment with a
hydraulic capacity of 32 MGD.
b. Plant 2, Activated Sludge Treatment Plant with a hydraulic capacity of 20 MGD.
a. Flow from both plants is commingled prior to Chlorine Contact Basin 2 (CCB2) where the effluent is chlorinated to meet the RWQCB’s requirements and dechlorinated prior to being
discharged to the Santa Ana River.
BACKGROUND
RiversideCA.gov
4 1. In May 2019, the City of Riverside received conditional approval from the State Water Control Board, Division of Drinking Water for the conversion of CCB2 chloramine disinfection to free chlorine disinfection.
2. Presently, CCB2 uses chloramine disinfection with a residual contact time of 450 milligrams-minutes per liter.
3. After construction, CCB2 will be using free chlorine disinfection with a free chlorine residual contact time of 30 milligrams-minute per liter.
DISCUSSION
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5 BENIFITS OF USING FREE CHLORINE WITH SHORTER CONTACT TIME:
1. Reduced disinfection by-products.
2. Reduce chemical dosages.
3. Reduced chemical costs.
4. Improve overall operational efficiency.
DISCUSSION
RiversideCA.gov
6 • On October 7, 2022, Bid No. 7935 was advertised by the City on PlanetBids.
• On November 17, 2023, three bids were received.
• The lowest responsive bid was from SCW Contracting Corp., in the amount of $1,431,185.
• Bid is 26.88% over engineers estimate of $1,128,000.
• Higher bid correlates to inflation and supply chain issues, which effects labor and material costs.
• Costs for labor and material may level off, but not decrease significantly to warrant project delay.
DISCUSSION
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4 RiversideCA.gov
7 Strategic Priority 6 - Infrastructure, Mobility and Connectivity Goal 6.2 – Maintain, protect and improve assets and infrastructure within the City’s built environment to ensure and enhance reliability, resiliency, sustainability, and facility connectivity
Cross-Cutting Threads
STRATEGIC PLAN ALIGNMENT
RiversideCA.gov
8 That the City Council:
1. Award a construction contract for Bid No. 7935 for the construction of Chlorine Contact Basin 2 (CCB2) Free Chlorine Modifications at Riverside’s Regional Water Quality Control Plant to SCW Contracting Corp. of Fallbrook, California, in the amount of $1,431,185; and
2. Authorize the City Manager, or designee, to execute the construction contract, including making minor and non-substantive changes, subject to the availability of budgeted funds.
RECOMMENDATIONS
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