Professional Services Agreement - Arcadis US - WWTP Stress Testing Evaluation

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d. Following the maximum peak flow determination in Task 6, use the process model to predict plant performance (e.g. primary, secondary) and effluent quality. For modeling purposes, this will assume that the disinfection can handle the maximum peak flow. e. Based on our results of this evaluation, determine phased process or operational improvements that would allow the plant to more reliably and efficiently treat increased peak plant flows. 5. Hydraulic Evaluation a. Update the hydraulic model developed for the WWTP Secondary Treatment Improvements project based on final construction, run the following scenarios, and update the profile: i. Current average flow conditions (based on Task 2) ii. Permitted 77 mgd peak flow condition (with new RAS rate based on Task 2 and 4) b. Develop hydraulic stress testing protocol to calibrate the hydraulic model and review protocol with Client staff in an onsite meeting. Update to incorporate the Client's input. As part of this meeting, review the hydraulic criteria (e.g. flow distribution, free drop, freeboard) and determine the desired criteria to be used for the hydraulic evaluation. C. During dry weather, perform on site stress test of the hydraulic capacity of the secondary treatment system. Each stress test will last a maximum of 15 minutes per set of secondary clarifiers and a total of up to five hydraulic stress tests as described below will be performed. Hydraulic stress tests will isolate sets of final clarifiers and aeration tanks to simulate high flows to online aeration tanks and online final clarifiers. Stress testing of other plant areas is not required because there have not been relevant changes in these areas. This assumes previous survey information can be utilized for this task. d. Update the hydraulic model based on the hydraulic stress testing findings. C. Using the calibrated model and trial and error, determine maximum peak hydraulic flow based on the current plant facilities (not including disinfection). £ Determine phased hydraulic improvements that could increase the peak flow beyond this and ultimately to reach the previous 100 mgd peak flow condition considering the recommendations from the 2013 WWTP Facilities Plan (e.g. primary effluent channel improvements, lengthening aeration tank weirs), and associated flow increase per improvement. Hydraulic improvements may be bundled for similar areas. g. Once the process is confirmed for the maximum peak flow, update the hydraulic profiles with the calibrated model for the following scenarios. Normal units in service will include 2/3 bar screens, 2/2 grit tanks, 8/8 primary clarifiers, 4/4 aeration tanks, one configuration of 75% final clarifier capacity, and 2/2 disinfection. The aeration tank out of service will be identical to this except with 3/4 aeration tanks. Units out of service will include 2/3 bar screens, 1/2 grit tanks, 7/8 primary clarifiers, 3/4 aeration tanks, one configuration of 75% final clarifier capacity, and 2/2 disinfection. Page 3 (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.