City Council Memorandum
TO: HONORABLE MAYOR AND CITY COUNCIL DATE: SEPTEMBER 22, 2026 FROM: PUBLIC WORKS DEPARTMENT WARD(S): ALL SUBJECT: CONSTRUCTION AGREEMENT FROM BID NO. 8236 WITH W. M. LYLES CO. OF FRESNO, CALIFORNIA FOR THE RIVERSIDE REGIONAL WATER QUALITY CONTROL PLANT BIOSOLIDS CENTRIFUGE 2 INSTALLATION FOR A PERIOD OF NINETY (90) DAYS FROM THE NOTICE TO PROCEED DATE, FOR A TOTAL AGREEMENT AMOUNT OF $1,190,000, AUTHORIZE 25% CHANGE ORDER AUTHORITY UP TO $297,500, FOR A TOTAL NOT-TO-EXCEED AMOUNT OF $1,487,500 ISSUE:
Consider awarding a Construction Agreement from Bid No. 8236 with W. M. Lyles Co. of Fresno, California for the Riverside Reginal Water Quality Control Plant Biosolids Centrifuge 2 Installation, for a period of Ninety (90) Days from the Notice to Proceed date, for a total Agreement amount of $1,190,000, and authorize 25% change order authority up to $297,500, for a total not-to-exceed amount of $1,487,500.
RECOMMENDATIONS:
That the City Council:
Award a Construction Agreement from Bid No. 8236 with W. M. Lyles Co. of Fresno, California for the Riverside Reginal Water Quality Control Plant Biosolids Centrifuge 2 Installation, for a period of Ninety (90) Days from the Notice to Proceed date, for a total Agreement amount of $1,190,000; Authorize a 25% change order in the amount of $297,500, for a total contract value of $1,487,500, to address unforeseen conditions including unknown electrical wiring, removal of obsolete and previously unidentified equipment, replacement of outdated control panels, and other unexpected appurtenances requiring upgrades to meet current code requirements; and Authorize the City Manager, or designee, to execute the Construction Agreement with W. M. Lyles Co. including making minor and non-substantive changes.
BACKGROUND:
The Riverside Water Quality Control Plant (RWQCP) treats wastewater generated within the City of Riverside and the communities of Edgemont, Highgrove, Jurupa, and Rubidoux. The RWQCP has a wastewater treatment capacity of approximately 52 Million Gallons per Day (MGD).
The solids handling facilities include thickening, digestion, and dewatering processes, whereas liquid handling facilities include preliminary, primary, secondary, and tertiary treatment processes. The solids handling facilities at RWQCP comprises of one centrifuge, two screw presses, and two belt presses for dewatering of digested sludge. The centrifuge yields a sludge concentration of 25% solids, which translates to a drier and lighter sludge, when compared with the screw presses and belt presses that are producing 19% and 14% sludge solids, respectively. Furthermore, the belt presses and screw presses are less reliable and require constant maintenance. As a result, the RWQCP operates the centrifuge as the primary dewatering unit, which equates to cheaper trucking and disposal costs. The belt presses and screw presses satisfy the requirement of 100% redundancy as emergency standby.
On December 19, 2023, the City Council awarded RFP No. 2222 for Biogas Upgrade and Digestate Management Facilities to Anaergia Services, LLC a Delaware limited liability company (LLC) doing business as Riverside Bioenergy Facility, LLC, a Delaware LLC. The City Council also approved the Lease and Energy Services Agreement with Riverside Bioenergy Facility, LLC a Delaware LLC, to accept and treat solid waste, particularly food waste, to improve anaerobic digestion at the RWQCP, to address regulatory challenges on climate, waste disposal, and biosolids management, and to maximize the potential of the RWQCP. Due to the anticipated higher solid contents from the acceptance of solid waste, the RWQCP was required to purchase a new centrifuge with higher capacity than the existing one.
On July 2, 2024, the City Council approved the purchase of one (1) Decanter Centrifuge unit Model CS26 – 4EV 2PH with Automatic Hydraulic Backdrive and one (1) Decanter Centrifuge Panel Upgrade for existing Centrifuge Model CS21 – 4HC to Centrisys-cnp. from Kenosha, Wisconsin, in the amount of $949,100 to process the current solids waste load and projected food waste from Riverside Bioenergy Facility. The new Centrifuge was manufactured and delivered to the RWQCP in December 2025.
DISCUSSION:
The existing centrifuge, installed in 2006, has consistently produced disposable sludge with higher solids content. However, on July 23, 2022, it experienced a catastrophic failure and was taken offline for extensive repairs. To ensure the RWQCP could continue operating in compliance with federal, state, regional, and local wastewater regulatory requirements, an emergency procurement was initiated to rent the necessary dewatering equipment at a rate of $13,836 per day, not including mobilization and demobilization costs. The addition of a second centrifuge will provide critical redundancy and allow for extended downtime needed to perform comprehensive maintenance on the older unit.
The total project cost, including equipment and installation, is $2,139,100. The project is expected to achieve a payback period of approximately 5.15 months, driven by the avoidance of dewatering equipment rental costs. This results in estimated monthly savings of $415,368 and annual savings of approximately $5,050,140. Based on these savings, the project yields an estimated return on investment (ROI) of 236%.
Table 1 – Return on Investment Analysis
Equipment Cost
$949,100
Installation Cost
$1,190,000
Total Project Cost
$2,139,100
Rental of Dewatering Equipment cost
$13,836/day
Project Payback in months
5.15 Return of Investment
236%
Purchasing Overview
On May 18, 2026, the City’s Purchasing Division (Purchasing) issued Request for Bids (RFB) No. 8236 on PlanetBids seeking prospective bidders for the Riverside Reginal Water Quality Control Plant Biosolids Centrifuge 2 Installation project.
The solicitation notification is summarized in the table below:
Action
Number of Vendors
External Vendors Notified
500
City of Riverside Vendors Notified
77 Vendors who downloaded the RFP
39 Proposals received
4 A mandatory pre-bid meeting was held on June 2, 2026, with nine (9) vendors in attendance. A total of 21 questions were received from prospective bidders, and two (2) addenda were posted. RFB No.8236 closed on June 25, 2026, with a total of four (4) responses. All bidders were found to be responsive and responsible.
The bid results are listed in the table below:
Vendor
Location
Bid Total
Rank
W.M. Lyles Co.
Fresno, CA
$ 1,190,000.00
1 SCW Contracting Corp.
Fallbrook, CA
$ 1,478,609.00
2 MMC, Inc.
La Palma, CA
$ 1,514,000.00
3 Pacific Hydrotech Corporation
Murrieta, CA
$ 2,054,400.00
4 Engineer’s Estimate:
$817,000.00
W.M. Lyles Co. was deemed the lowest responsive and responsible bidder. The lowest bid exceeds the engineer’s estimated amount by $373,000.
This action is pursuant to Purchasing Resolution 24101, Section 508 which states, “Contracts procured through Formal Procurement shall be awarded by the Awarding Entity to the Lowest Responsive and Responsible Bidder.” The Purchasing Manager concurs that the recommended action is compliant with Purchasing Resolution 24101.
FISCAL IMPACT:
The total fiscal impact of the actions of this report is a total of up to $1,487,500, which includes a change order authority amount of $297,500. Funding for this award is budgeted and available in the Sewer Fund, Re Rehab of the Biosolids Equipment project number 9917823-440301. Total estimated project costs are listed below in Table 1.
Table 1. Total Estimated Project Costs
Project Task
Account
Amount
W.M. Lyles Co. Contract
9917823-440301
$ 1,190,000
Construction Contingencies
9917823-440301
$ 297,500
In House Engineering and Inspection (10% of Contract)
9917823-440301
$ 119,000
Total
$ 1,606,500
Prepared by: Usha Kademani, Associate Engineer
Approved by: Nathan Mustafa, Public Works Director
Certified as to
availability of funds: Julie Nemes, Finance Director
Approved by: Kris Martinez, Assistant City Manager
Approved as to form: James Johnson, City Attorney
Attachment: Award Recommendation
Bid 8236 - Riverside Reginal Water Quality Control Plant Biosolids Centrifuge 2 Installation h Page 5