Agenda Packets - 1994/07/25 - Laserfiche WebLink

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MEMO TO : Samantha Orduno, City Administrator FROM : Michael Ulrich, Director of Public Works DATE: July 19, 1994 SUBJECT: Installation of flush out system at Water Treatment Plant #1 Several months after the operational changes had been resolved with the new water treatment plant, Water Operators Bill Hanson and Bill Hanggi reported that the slope of the reclaim tank was not adequate, therefore the sludge was not being removed from the tank sufficiently. They proposed to install a high pressure water flush system, to agitate the sludge into a suspended state, in which the pump could then discharge. Due to the other plant revisions taking place during this time, and other routine maintenance procedures, the flush out system had to be delayed. Throughout the past two years, when ever the reclaim tank needed to be cleaned out (every 2 months) , it was a task that required 3 operators to manually clean the tank. Not only was this task labor intensive, but it also required that staff disinfect the tank because the backwash water is pumped back into the filter and into the system. The process of manufacturing and installing a flush out system involved calculating the required flow per nozzle, tapping a water main inside the plant, drilling a 2 1/2 inch hole in the floor, installing a backflow preventer, plumbing all pipes, fittings and nozzles, and fastening pipes at the proper height and position in the tank, and installing an electrical solenoid valve to provide for automatic control. Material and labor is estimated to cost $3, 500. The expense of manual cleaning was approximately $1, 225 per year, making the payback of this installation about three years. Even though this project was very cost efficient, more important is the fact that the city no longer risks the possible contamination of the water system by entering the reclaim tank. Bill Hanson and Bill Hanggi deserve the highest of gratitude from the City of Mounds View for their ingenuity, professionalism, and workmanship in the construction of this project.