Amendment No. 1 to PSA - WWTP Final Clarifier Proj No. 119-069 – Arcadis U.S., Inc.

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STANDARD AGREEMENT FOR PROFESSIONAL SERVICES Page 2 of 6 Between City of South Bend and ARCADIS U.S., Inc. Project Number: 30029091 AMENDMENT No. 1 SB WWTP Final Clarifier 123 Construction_Amendment No. 1.docx Schedule A-1 Scope of Amended Services and Related Matters ENGINEERING SERVICES BY ARCADIS Final Clarifier Nos. 1 through 3 Rehabilitation. The WWTP has seven final clarifiers. Final Clarifier Nos. 1 through 3 (112.5 ft dia.) were part of the original plant constructed in the early 1950s. Final Clarifier Nos. 4 and 5 (145 ft dia.) were added in the 1970s. Final Clarifier Nos. 6 and 7 (200 ft dia.) were added in the 1970s as tertiary clarifiers. In 2001, all final clarifiers were rehabilitated with new collector mechanisms, skimmers (Nos. 1 to 5 only), effluent weirs, and return sludge pumps. Final Clarifier Nos. 6 and 7 were converted from tertiary clarifiers to final (secondary) clarifiers during that time. As part of the recent WWTP Secondary Treatment Improvements project, Final Clarifier Nos. 6 and 7 were rehabilitated and enhanced and are operating exceptionally well (e.g. concentrated return sludge allowing lower pumping rates). As part of the WWTP Secondary and Disinfection Improvements project, Final Clarifier Nos. 4 and 5 were rehabilitated. Final Clarifier Nos. 1 through 3 have reached the end of their useful life and are in need of rehabilitation and replacement similar to Final Clarifier Nos. 4 through 7. Final Clarifier Nos. 1 through 3 are each 112.5 feet in diameter with a sidewater depth of 12 feet. The sludge collector mechanisms are suction sludge removal type. The clarifiers are drained by their associated return sludge pumps. Skimmings removal is provided in all clarifiers. As part of this project, the internal clarifier equipment including the sludge collector mechanisms and scum removal will be replaced. The influent and effluent troughs, and effluent weirs will be replaced and provided with concrete channels. The existing scum removal beyond that being replaced internal to the clarifiers will be reused. In addition, the clarifier structures will be inspected and rehabilitated and repaired, as necessary. The exposed concrete and just below the water line will also be coated. The limits of the structural inspection and rehabilitation include within the concrete tank structures only. Railing will be replaced; limits include these clarifiers and the final clarifier influent channel leading into these clarifiers from the main channel. The individual influent channels into each of Final Clarifier Nos. 1 through 3 also require improvements to eliminate this area overtopping during peak flows and spilling into the gallery buildings. The clarifier drive mechanisms are monitored by SCADA. Instrumentation and controls (i.e. over-torque alarm) will be provided, and HMI screens will be updated to match Final Clarifier Nos. 4 through 7. The clarifier equipment is electrically fed from their associated gallery buildings, which has been replaced through another City project and is assumed can be reused. These clarifiers will primarily be used during wet weather when the plant exceeds 77 mgd and is required to treat 100 mgd as part of the CSO LTCP requirement. Considering this and due to market conditions, these clarifiers will be replaced and rehabilitated in-kind, matching their current rim feed configuration. This project entails updating the prior Final Clarifier Nos. 1 through 3 design to replace and rehabilitate the clarifiers as perimeter feed type clarifiers, and to provide construction administration services during the City’s selected Guaranteed Savings Contract type delivery method, already awarded to the contract. The scope of engineering services shall include the following: 1. Project Management. Provide project management including scope, budget and schedule control; project coordination; maintenance of records; project setup, invoicing, and close-out. 2. Design Updates. Update the contract documents to replace and rehabilitate the clarifiers as perimeter feed type clarifiers. Upon acceptance of the Guaranteed Maximum Price, the following construction services apply. 3. General Administration of Construction Contract. Consult with Owner and act as Owner’s representative as provided in the Construction Contract. The extent and limitations of the duties, responsibilities, and authority of Engineer as assigned in the Construction Contract shall not be modified, except as Engineer may otherwise agree in writing. All of Owner’s instructions to Contractor will be issued through Engineer, which shall have authority to act on behalf of Owner in dealings with Contractor to the extent provided in this Agreement and the Construction Contract except as otherwise provided in writing. 4. Pre-Construction Conference. Participate in a Pre-Construction Conference prior to commencement of Work at the Site. The conference will be attended by Engineer.