13-2527 Amendment 1 to Supplemental Agmt 7 w Reiss Engineering, Inc - South Water Treatment Plant

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AMENDMENT NO. I TO SUPPLEMENTAL AG EENtENT NO. 7 SCOPE OF SERVICES City of Casselberry Additional Design Services for South Water Treatment P1 ant Gr,annanllarrActiva�ii;ed Carbon Treatment Addition August 20, 20113 if. INTRODUCTION The City of Casselberry (City) is in the process of upgrading treatment at the South Mater Treatment Plant (South WTP) by adding granular activated carbon (GAC) to improve the water distributed to its customers. The City authorized Reiss Engineering, Inc. (REI) with the design of the GAC process under Supplemental Agreement No. I in January 2013 and REI has worked on the design with input from the City. Under Supplemental Agreement No. 7, the GAC process was designed for a maximum daily demand of 2.5 MGD (1,740 gpm) with four (4) GAC vessels. During design, it was decided that the City would like to design for an instantaneous maximum flow rate of 3.74 MGD (2.,600 gpmn) to allow additional flexibility of operations. To accommodate the increase in flow, four (4) GAC vessels will be used for treatment while one (1) GAC vessel is out of service for maintenance. This will require the addition of a fifth GAC vessel to the design. In addition to expanding the treatment capacity of the GAC process, the inclusion of the fifth GAC vessel provides the City with complete redundancy of vessels in the; GAC process if a vessel is out of service for maintenance. During the design, it was decided that the City would like to use a V -port ball valve with automated controls on the GAC process instead of a pressure sustaining valve that is hydraulically operated. The City desires the V -port ball valve because it is less maintenance intensive as compared to the pressure sustaining valve. It was also decided during the design that the City would select a Construction Manager At Risk (CMAR) to perform the construction improvements. REI will provide additional coordination efforts between the City and the CMAR to transition from the design phase to the construction phase.