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HomeMy WebLinkAboutMN-BPW-2010-02-05BOARD OF PUBLIC WORKS PROCEEDINGS CITY OF ITHACA, NEW YORK Special Meeting 1:00 p.m. February 5, 2010 PRESENT: Mayor Peterson Commissioners (3) – Brock, Tripp, Wykstra OTHERS PRESENT: City Attorney – Hoffman Superintendent of Public Works – Gray Assistant Superintendent of Water and Sewer – Whitney Common Council Liaison – Zumoff Executive Assistant – Gehring Director of Planning & Development – Cornish Chief Water Plant Operator – Baker Asst. Civil Engineer – Sledjeski Environmental Engineer – Gibson O’Brien & Gere Consultant – Rick Gell Watek Consultant – Ben Movahed Natural Areas Commission Member – Todd Miner Treva Avenue Neighbor and County Planning Dept. – Scott Doyle Water Street Neighbor – John Ochshorn Giles Street Neighbor – Bill Hnat EXCUSED: BPW Commissioner – Jenkins Acting Asst. Superintendent of Streets & Facilities - Benjamin DAC Liaison – Roberts SPECIAL ORDER OF BUSINESS Water Plant Membrane Pilot Study – Discussion Mayor Peterson introduced the consultants, neighbors and other interested parties in attendance for the presentation. O’Brien & Gere Consultant Gell explained the piloting phase of the membrane study would begin in the near future. He stated that O’Brien & Gere would like to ensure that all questions are answered, and noted that there are energy-related concerns the group needs to consider. Supt. Gray explained the history of water filtration systems used in the past and what may be used now. He noted that sand filtration systems can no longer filter some contaminants. Discussion followed on the floor regarding expected costs related to a new filtration system. Supt. Gray responded that final costs would be determined once the membrane system is chosen. Watek Consultant Ben Movahed presented a chart showing all of the natural water contaminants and explained the different membrane filtration processes that could be considered. He stated that the City should consider the Microfiltration and Ultrafiltration (MF/UF) systems, which remove over 90% of contaminants in the water. He further explained that the highest costs at water treatment plants with membrane filtration systems are energy costs; however, when plants change to membrane filtration, they use 30-50% fewer chemicals. He further explained that the City could use tubular membranes and hollow fiber membranes at the water treatment plant. He noted that more manufacturers are making hollow fiber membranes than tubular membranes. He elaborated that with a MF/UF system, that the City must choose either pressurized or submerged filtration process. He showed the difference between pressurized and submerged multifiltration/ ultrafiltration membranes. Discussion followed on the design, electrical costs, and gravity of the new system. He provided photos of both pressurized and submerged membrane filtration systems and noted some of the advantages and disadvantages for each system. 2 February 5, 2010 Extensive discussion followed on the floor regarding fitting the new water plant on the existing site, the hydraulics of the system chosen, and precautions that would be taken so that part of the plant will continue to operate in case of power outages. Further discussion followed on the floor regarding the number of pumps required for the water plant. Discussion also followed on the floor regarding the ability to provide water in an emergency (fire) through gravity and planning for future expansion of the plant. Mr. Movahed explained two ways to determine the health of the membrane systems: 1. Use of a particle counter, which detects different sizes of particles, including those that are much smaller than what a sand filtration system can capture; and 2. Pressure Decay Test (PDT), now required by New York State, which can detect five to six broken fibers in a few seconds of testing. The test applies air into the fibers to detect the exact location of any leak. Discussion followed on the floor regarding the repair, replacement of the fibers, modules, requirements for the new membrane plant, and two options for purchasing membrane systems: Further discussion followed on the floor regarding the pilot studies that will be conducted, to determine which technology would best meet the needs of the City. Mr. Movahed stated that a small building should be constructed for the pilot studies and that the same water is provided for all studies. He further explained that up to four vendors would be tested. He stated that only manufacturers with plants located in the United States who have been in operation for at least two to three years would be selected. Mr. Movahed stated that the MF/UF system would meet future water treatment regulations so the new water plant will last for the next 100 years without any major changes required. Discussion followed on the floor regarding the types of contaminants that the MF/UF system would remove and the costs related to building a conventional plant versus a membrane filtration plant. Further discussion followed on the floor regarding whether a decision had been made to build a membrane plant or a conventional plant. Mayor Peterson suggested that the Board decide in the near future about the number of pilot studies to conduct and whether to study more than one type of membrane system. ADJOURNMENT On a motion the meeting adjourned at 2:10 p.m. ______________________________ _____________________________ Kathrin D. Gehring Carolyn K. Peterson Executive Assistant Mayor