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HomeMy WebLinkAboutSP April 30, 1998 , Special City Council Meeting'; Thursday, April 30, 1,998 Call to Order - Following Board of Review Meeting held at 7:00 PM 1. '. " .J CITY OF ANDOVER REQUEST FOR COUNCIL ACTION \. DATE: April? 1998 AGENDA SECTION Staff, Committees, Commission ORIGINATING DEPARTMENT Scott Erickson, "- Engineering ITEM NO. 10. Information on Lift Stations As the development within the City of Andover begins to reach the limits of the anticipated sanitary sewer service area we are and will continue to be confronted with the issue of our ability to service these areas with gravity sanitary sewer. As a result we will need to further discuss the philosophy of lift stations and the technical aspects behind them, As this is a significant deviation from the policy and mind set of the city a lot of discussion and information will need to be presented on this issue. PHILOSOPHY Andover's philosophy regarding its sanitary sewer system has predominantly been that gravity sanitary sewer will be utilized in place of sanitary sewer lift stations. This has in fact been the case, with one exception of a temporary lift station being installed for The Meadows of Round Lake development in 'anticipation of the CAB interceptor being constructed at some time in the future. , Although "there may be other scenarios, I have identified three examples where a discussion on sanitary sewer lift station would come up: 1, In-filling of existing low areas within the current MUSA boundary. This may occasionally occur when the trunk sanitary sewer begins to reach the previously identified MUSA boundary. When we begin to reach the limits of the sanitary sewer service area the cover over the gravity pipe is minimal. If there are low areas as we reach the MUSA boundaries or the pipe begins to .come out of the ground" we will be faced with options of sanitary sewer lift station, 2. MUSA Boundary Extensions or Keep the Boundary Where it Currently is. This discussion is currently taking place with the comprehensive plan task force. The use of sanitary sewer lift station would allow for modification to this boundary if the Council so chose. It should be noted that we are limited by the capacity of our sanitary sewer trunk that exits at the south end of the city. The system would need to be re-analyzed to determine if in fact we have any excess capacity at this location. 3, By-passing agricultural lands or lands not ready to develop, There may be occasions where politically this option will be discussed by the council. An example of this would be the next phase of the Winslow Hills development. TECHNICAL INFORMATION :The concept and use of sanitary sewer lift stations is not new in the industry. Lift stations have been in - - use for many years not only in the metro area but throughout the United States. Although not entirely fail safe the technology and maintenance behind sanitary sewer lift stations has improved over the years. Some examples of these improvements are as follows: 1. A redundant pumping system, two pumps are installed, to help insure the reliability of the system. -") Only one pump is actually needed to run the lift station so the second pump acts as a backup for the I system, The pumps themselves have become very reliable and require minimal maintenance and repair. 2. The sanitary sewer lift station are equipped with a computer monitoring system (SCADA) which detect problems and notify the maintenance personnel immediately. The SCADA system currently monitoring our municipal wells would be utilized to monitor the lift stations. 3, The routine maintenance of the lift station has been reduced through improvements to equipment and controls. A detailed maintenance program is important to insure a reliable system. 4. Lift station are equipped with a generator connection to provide for the possibility of a power outage. 5. Liftstation controls have been brought above ground to provide easy access and maintenance and to also provide a safe environment for the maintenance personnel. It is no longer necessary, in new installations, for the maintenance personnel to have to enter an underground lift station, 6. There is additional maintenance involved with a lift station. Similar to a municipal well house, a lift station is typically checked three times a week. Although relatively maintenance free there is periodic rebuilding of pumps and motors of a station, The maintenance is typically funded from the public Works sewer budget. . These are a few of the technical items that may help the council better understand the reliability and maintenance of a lift station, We have contacted the maintenance personnel of both the City of Anoka '"') and the City of Fridley regarding the maintenance of their lift stations, Anoka currently maintains 20 lift' , stations while the City of Fridley maintains 14. There were no real horror stories regarding problems with the facilities and both cities have been operating and maintaining the lift stations for many years (Fridley's oldest was approximately 45 years old). They did clearly indicate that routine maintenance is necessary and they have had to deal with power outages, pump replacements, etc... over the years. We hope this provides the Council with some background and history on the issue of lift stations, If any additional information is needed or desired we will provide that at the Council's request. ;~ ',-- j