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Kennedy/Jenks Consultants Memorandum John Marlow, Owner 1 April 2009 Page 2 1 also spoke with you by telephone that day and said that I could be available to further discuss these issues with the EHD and others upon my return 1 April 2009. 1 received messages from Mr. Hakeem on my return that he had transmitted my comments to the County, had received a letter from Mr. Irey, 20 March that stated the same 3 comments for acceptance as the previous fax, and that a meeting to discuss these issues will be conducted on 3 April. This memorandum provides opinions and documentation why neither 1 or 2 are necessary. Also it was thought that the installation of the residual chlorine analyzer, chart recorders, distribution pressure sensors, recorders and alarms was for pilot and demonstration testing and not a condition for continuing use for such a small ground water supply with no recent record of coliform or water pressure insufficientcy. Storage Tank and Booster Pump: The "Adedge" pyrolusite filter systems utilize a backwash supply that is provided by filtration through other filters in the train. The manufacturers' data sheets on these filters were provided in my report of 4 December 2007. The suggested operating conditions are for a service flow rate of 8-12 gpm/sf and a backwash flow rate of 18-20 gpm/sf. This translates to a service flow rate for 2 filters in operation of 50.2 to 75.4 gpm and a backwash rate of 56.5 to 62.4 gpm The selected 60 gpm rate for backwash is appropriate for the WTP. The question of the adequacy of the 60 gpm Islander Well was questioned by EHD at our meeting last June, it was assumed that the automatic programming of backwash at 3 AM; a time of very minimal water demand, plus the additional flow capacity available from the well pump at lower pressure, should provide adequate flow for both backwash and any distribution needs. This issue was addressed in item 3a of my letter of 24 June 2008, which indicated that a well pump for 60 gpm at 60 psi would discharge 85 gpm, at 40 psi and over 110 gpm at 25 psi. Thus, with respect to insufficiency of reliable water supply, there is none. The installation of a storage tank and pump will only complicate the system as it is always desirable to keep small water systems simple to operate and maintain. It is acknowledged there were several low pressure indications on the distribution charts during last Fall's pilot tests. But as described in my letter report of 4 December 2008, that there was also a near concurrent off the chart high pressure indication. As explained it is most likely due to a water hammer source, which is best addressed by check valve or other operation pressure suppression. There was no indication of the low pressure surge occurrence with the Bar Well or subsequent demonstration testing of the Islander water. 9T,uouP` nirctyhyW;�9:'ehiic ismtlenra6dtYwizPm!.`llwcrspnC�lMrr;. menmra„d�mjahn nnatbx 04.01.09.tloc ©Ke=.uietl ysJaMcs CWGUIITll6.enc.