R2016-15 PROFESSIONAL ENGINEERING SERVICES AGREEMENT SWTP CLARIFIERS

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-2 - � Moderate reduction in the cost to recycle the lime residual byproduct of the water purification process. • Unlike the current clarifiers, claricones do not operate in pairs. Instead, they operate independently which provides a very high degree of water purification flexibility and system redundancy. • Each pair of current clarifiers can treat 18 million gallons per day of water. Two claricones can treat 20 million gallons which is an 11% increase. • There are no operational disadvantages of claricones. In order to determine the long term financial impacts of rebuilding all four clarifiers or converting them to claricones, a 25 year present value analysis (assuming 2 % annual inflation) was completed for both options. The results of the analysis are that converting the clarifiers to claricones is essentially the same long term cost as rebuilding them. See Attachment C far details. It is important to note that the useful life expectancy of claricones is approximately 40 years compared to the approximately 25 year life expectancy of rebuilt clarifiers. 25 Year Cost to Rebuild the Clarifiers $76,934,150 Net Present Value $47,980,1 ll 25 Year Cost for Claricone Conversion $72,990,438 Net Present Value $48,407,481 In 2013 the City Council approved the Reliable Water System Program which included water rate increases to fund the replacement of aging system components such as the clarifiers. Since converting the clarifiers to claricones is far superior to rebuilding the clarifiers, a Request for Qualifications and Proposals to perform this work for the East clarifiers was issued in October with proposals due on December 15, 2015. Ten engineering firms were also directly notified of the request. Three proposals were received and independently evaluated by a five member City staff panel. A summary of the proposal costs is shown in Attachment D. The panel's consensus was that Crawford, Murphy and Tilly, Inc. (CMT) was best suited for this project for these reasons: • CMT has significantly more experience with claricones compared to the other firms. • CMT has the most experience with large concrete claricones including 3 claricones for the City of Springfield that are very similar to Decatur's. The other firms do not have this experience. • The same CMT staff that worked on Springfield's claricone projects would be assigned to Decatur's project. • CMT's proposal was for a significantly lower cost than the other proposing firms.