===== PDF PAGE 70 ===== [Extraction: embedded PDF text] CITY OF WEST CHICAGO INFRASTRUCTURE COMMITTEE AGENDA ITEM SUMMARY ITEM TITLE: AGENDA ITEM NUMBER: Resolution No. 25-R-0061 - Change Order No. 1 - COMMITTEE AGENDA DATE: August 7, 2025Independent Mechanical Industries for the A2O COUNCIL AGENDA DATE: August 18, 2025 Phosphorus Removal Project for the West Chicago/Winfield Wastewater Authority Regional Wastewater Treatment Plant in an Amount Not to Exceed $105,800.00 for a Revised Contract Amount Not to Exceed $5,120,800.00 STAFF REVIEW: Mehul T. Patel, P.E., Director of Public Works SIGNATURE, _________ _ ITEM SUMMARY: The West Chicago/Winfield Wastewater Authority (WCWWA) Regional Wastewater Treatment Plant (WWf P) operates under an NPDES permit regulated by the Illinois Environmental Protection Agency (IEPA); Permit No. IL0024369. As authorized by the Clean Water Act, the NPDES Permit Program controls water pollution by regulating point sources that discharge pollutants into waters of the United States. Water pollution degrades surface waters, making them unsafe for drinking, fishing, swimming, and other activities. Industrial, municipal, and other facilities must obtain permits from the IEPA if their discharges go directly to surface waters and must renew their permits every five years. For years, the USEPA has pressured the IEPA to impose new and stricter nutrient removal limitations on wastewater treatment plants consistent with national policy. The most recent IEPA NPDES permit for the WCWWA wwrP expires on April 30, 2027. Since 2015, the WCWWA has been a member of one local environmental group, the DuPage River Salt Creek Workgroup (DRSCW), formed in 2005 in response to concerns about Total Maximum Daily Loads (TMDLs) being set for the East & West Branches of the DuPage River and Salt Creek, which is made up of local communities, Publically Owned Treatment Works (POTWs) or wwrPs, and private environmental organizations. The DRSCW has been working to produce comprehensive data sets for local watersheds to determine and resolve priority stressors to local aquatic systems. The organization continues to implement targeted watershed activities that resolve priority waterway problems efficiently and cost effectively. Working directly with the other environmental groups and the IEPA, the DRSCW has created, submitted, and received support for the implementation of special permit conditions and stream restoration projects. It is DRSCW's plan that implementation of its stream restoration projects will produce the greatest improvement in water quality and habitat for less money than individual POTW projects. Because of being a member of the DRSCW and paying Project Funding Assessments, participating POTWs received a temporary reprieve from the IEPA to upgrade its own POTW and comply with strict phosphorus limits likely to be imposed by the IEPA. The WCWWA agreement with DRSCW expired on December 31, 2022, at which time WCWWA stopped paying Project Funding Assessments. As a result, in WCWWA's current NPDES permit, a special condition has been added which states the total phosphorus removal limits of 1.0 mg/I would be effective Oct 1, 2026. On December 7, 2020, authorized by Resolution No. 20-R-0076, the Mayor executed a contract with the Donohue & Associates, Inc. (Donohue) for a Phosphorus Removal Pilot Study at the West Chicago/Winfield Wastewater Authority (WCWWA) Regional Wastewater Treatment Plant. This Study was completed and the final report was provided in January 2022. The study recommended four different options to reduce the total phosphorus limits below 1.0 mg/I. After review of the report and discussions with wwrP contracted staff, the consensus is to implement an option called "Anaerobic/Anoxic/Oxic (A2O)" to achieve the total phosphorus limits. This option will also provide the WCWWA with total nitrogen removal, limits for which will be coming down the road. With this option, the Study shows, WCWWA can achieve 0.37 mg/I total phosphorus removal limits, which would be siQnificantly below the 1.0 mQ/1. The IEPA has previously suQQested more strinQent total phosphorus limits ===== PDF PAGE 71 ===== [Extraction: embedded PDF text] CITY OF WEST CHICAGO including 0.5 mg/I and 0.1 mg/I. On February 20, 2023, the City Council authorized Resolution No. 23-R-0006 authorizing Donohue to perform all required design engineering services related to the A2O Phosphorus Removal Project. On May 20, 2024, the City Council authorized Resolution No. 24-R-0045 to approve a Contract with Independent Mechanical Industries of Elk Grove Village, Illinois, for the A2O Phosphorus Removal Project at the West Chicago/Winfield Wastewater Authority Regional Wastewater Treatment Plant in an amount not to exceed $5,015,000.00. The Project scope of work includes physical modifications to the existing aeration basins, pulled air mixing system, electric actuators, pumps, diffusers and other necessary items. Please note, the current Project scope was reduced significantly to stay within budget. The major cuts included removing Return Activated Sludge (RAS) pumps, chemical polishing system, and modified electrical scope. By implementing the reduced Project scope, WCWWA can achieve 0.6 mg/I total phosphorus removal limits, which would be below the 1.0 mg/I. The construction on this Project began in fall 2024 and was suspended through the winter 2024-25 season. The construction resumed in March 2025. To date, the Project has run into some unforeseen circumstances as well as some necessary changes that are required for completing the Project. To date, ten additional scope of work items have been identified. The following table summarizes the additional work and its associated costs. No. Additional Work Item Reasoning for additional work Cost 1 Stainless Steel Internal Mixed Liquor Material change request by the $(54,000.00) Recirculation {IMLR) Piping in lieu of contractor to provide project savings Ductile Iron Pipe 2 IMLR Pump Variable Frequency Drive In order to obtain a standard IMLR $13,478.00 Upsize pump (without integral VFD) , VFD size needed to be upsized to accommodate next standard. 3 Selector Zone Wall Flaps Allow drainage and still prevent short- $29,209.00 circuiting or mixing of aerated wastewater with the non aerated anoxic selector zone while in service. 4 Remove Aeration Tank Effluent Weir Lower aeration tank water elevation on $12,696.00 downstream side of anoxic zone selector wall to enhance positive flow to aerobic zone. 5 Conduit work for Compressor Denied $0 6 Switch panel support area from concrete Grating allowed room for existing $(973.00) to fabricated/ grated piping under the walkway compared to a concrete slab. 7 Aeration Tanks 3 and 4 stop gate delete Gates are failing and/or stuck as well $16,709.00 and fill wall opening as some deteriorated concrete around the gates 8 Aeration Tank 3 Cleaning Additional Cleaning required after $11,631.00 failure of existing gate on Tank 3 allowed mixed liquor into the tank while it was down for improvements. 9 Aeration Tanks 1 and 2 stop gate delete Gates are failing and/or stuck as well $77,050.00 and fill wall opening as some deteriorated concrete. All project costs, including this change order, are funded by the West Chicago/Winfield Wastewater Authority WCWWA and do not im act the Cit 's General Fund. ===== PDF PAGE 72 ===== [Extraction: embedded PDF text] CITY OF WEST CHICAGO ACTIONS PROPOSED: Approve Resolution No. 25-R-0061 authorizing the Mayor to execute a Change Order No. 1 with Independent Mechanical Industries of Elk Grove Village, Illinois, for the A2O Phosphorus Removal Project at the West Chicago/Winfield Wastewater Authority Regional Wastewater Treatment Plant in an amount not to exceed $105,800.00 for a Revised Contract Amount Not to Exceed $5,120,800.00 COMMITTEE RECOMMENDATION: ===== PDF PAGE 73 ===== [Extraction: embedded PDF text] RESOLUTION NO. 25-R-0061 A RESOLUTION AUTHORIZING THE MAYOR TO EXECUTE A CHANGE ORDER NO. 1 WITH INDEPENDENT MECHANICAL INDUSTRIES OF ELK GROVE VILLAGE, ILLINOIS, FOR THE A2O PHOSPHORUS REMOVAL PROJECT AT THE WEST CHICAGO/WINFIELD WASTEWATER AUTHORITY REGIONAL WASTEWATER TREATMENT PLANT IN AN AMOUNT NOT TO EXCEED $105,800.00 FOR A REVISED CONTRACT AMOUNT NOT TO EXCEED $5,120,800.00 BE IT RESOLVED by the City Council of the City of West Chicago, in regular session assembled, that the Mayor is hereby authorized to execute a Change Order No. 1 with Independent Mechanical Industries of Elk Grove Village, Illinois, for the A2O Phosphorus Removal Project at the West Chicago/Winfield Wastewater Authority Regional Wastewater Treatment Plant in an amount not to exceed $105,800.00 for a Revised Contract Amount Not to Exceed $5,120,800.00, m substantially the form attached hereto and incorporated herein as Exhibit "A". APPROVED this 18th day of August, 2025. AYES: NAYES: ABSTAIN: ABSENT: Mayor Daniel Bovey ATTEST: Executive Office Manager Valeria Perez