Professional Services Agreement - Arcadis US Inc - Secondary Treatment and Disinfection Improvements at WWTP

Home Browse Search

This is EXHIBIT A, consisting of 11 pages, referred to in and part of the Agreement between Owner and Engineer for Professional Services dated , Engineer's Services Article 1 of the Agreement is supplemented to include the following agreement of the parties. Engineer shall provide Basic and Additional Services as set forth below. PART 1— BASIC SERVICES The City of South Bend desires to continue its efforts to rehabilitate, modify and expand the WWTP to work towards achieving the CSO Long -Term Control Plan requirement, which ultimately requires an increase in the peak wet weather capacity at the WWTP from 77 mgd to 100 mgd. This WWTP Secondary and Disinfection Improvements Project entails three major project components as follows: • Final Clarifier Nos. 1 through 5 Rehabilitation • Aeration Tank Nos. 1 through 4 Modifications • Effluent Disinfection Chemical Expansion This project does not include an increase in permitted peak flow capacity; however, these improvements are a critical component of the plant's ability to treat the future peak flow. The focus of this project is to complete the remaining final clarifier and aeration tank aging equipment, process and hydraulic needs building upon the recent, successful WWTP Secondary Treatment Improvements project, and expanding the effluent disinfection chemical system. The improvements will be designed to provide the future required 100 mgd peak flow, assuming IDEM approval can be obtained for less than 15 minutes contact time for disinfection (in the future). The secondary improvements have the added benefit of better process control, particularly through the ability to control return sludge, which will result in better treatment, reduced energy costs, improved secondary treatment hydraulics, and ease of operation and maintenance — all of which will positively impact the current plant operations and prepare the plant for the future. The disinfection improvements will expand the chemical systems to dose at higher concentrations during variable wet weather periods to ensure compliance. Final Clarifier Nos. 1 through 5 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. l 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). Final Clarifier Nos. 1 through 5 have reached the end of their useful life, and are in need of rehabilitation, replacement, and enhancement similar to Final Clarifier Nos. 6 and 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. Final Clarifier Nos. 4 and 5 are each 145 feet in diameter with a sidewater depth of 14 feet. The sludge collector mechanisms are also suction sludge removal type. The clarifiers are drained Page 1 (Exhibit A — Engineer's Services) EJCDC E-500 Agreement Between Owner and Engineer for Professional Services Copyright © 2008 National Society of Professional Engineers for EJCDC. All rights reserved.