R2026-124 Resolution Authorizing Agreement with Burns and McDonnell Engineering Company, Inc., to Provide Professional Engineering Services to the City of Decatur for the South Water Treatment Plant Expansion Plan, City Project 2025-03

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Evaluation Procedures for Granular Media (total of 24 core samples). The core should be collected after each filter has been in service for a typical filter duration (or maximum allowable before breakthrough if required by higher loading rate). Core samples will be collected by the City. (3) Develop a solids retention profile per AWWA Filter Evaluation Procedures for Granular Media for each of the filters to determine depth of solids removal within the filter bed before and after backwash (by BMcD) (4) Evaluate the overall effectiveness of backwash process based on the collected flowrate,duration, and solids retention profiles(by BMcD). c) Develop conceptual designs and conceptual-level (AACE Class 5) cost estimates for the rehabilitation and/or replacement of filter media, underdrains, and backwash system components required to achieve a range of future target capacities. For the new filter building, identify a range of the number of new filters, associated building sizes, and filter material (sand/anthracite, GAC, etc.), and design flows the City could build and operate.A total of five (5) filter expansion/rehabilitation options will be considered. The analysis will include the following design considerations: i) Filter to Waste (FTW)provisions. ii) A new filter inlet concept to allow for improved isolation of existing filters for rehabilitation. iii) Backwash system modifications to support system upgrades, considering hydraulic requirements (minimum 20 feet of head pressure, with greater than 22 feet preferred). iv) Filter media improvements using dual-media(sand and anthracite). v) GAC sizing is dependent on empty bed contact time (EBCT). For the purposes of this task, 10-minute and 20-minute EBCT options will be evaluated. Prior to finalizing GAC, additional full scale pilot testing is suggested(excluded from this scope). d) Filter Expansion Workshop i) To be combined with the Clarifier workshop (see Task 3). ii) Organize and facilitate one (1) virtual workshop (up to 2 hours) with the City to present the findings of the filter analysis and the preliminary design alternatives. iii) The purpose of this workshop is to discuss the alternatives and for the City to select a preferred path forward for the preliminary design. iv) A summary of the workshop, which may be in the form of meeting minutes or notes and/or presentation slides, will be provided to document the decisions made by the City. 6) STORAGE AND DISINFECTION TANK ANALYSIS a) Analyze existing CT calculations to identify trends regarding amount of CT provided during different seasons. b) Compare the existing finished water storage capacity against current and projected future demands provided by the City. c) Develop a conceptual volume for a new CT basin(or tank) by analyzing the minimum required volumes for the following scenarios (1)high plant flow and low temperature restrictive conditions (2) low plant flow and high temperature restrictive conditions, and (3) average plant flow conditions. These scenarios will define the minimum, average, and maximum volumes needed for CT. The conceptual design will be based around an achieving an assumed minimum baffling factor of 0.7, per EPA Disinfection Profiling and 5