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HomeMy WebLinkAbout20111212 UC Minutes Ros�MOUNT PUBLIC WORKS DEPARTMENT UTILITY COMMISSION MINUTES December 12, 2011 Pursuant to due call and notice thereof the regular Utility Commission meeting of the City of Rosemount was called to oYder on December 12, 2011 at 5:30 p.m. in the Conference Room of the City Hall by President Don Harmsen. Those present were Commission Members Mulhern, Speich, Mayor Droste, Executive Director Bxotzler, Operations Superintendent Cook and Recording Secretary Dorniden. ADDITIONS OR CORRECTIONS TO THE AGENDA None. AUDIENCE INPUT None. MOTION by Speich to approve the minutes of the September 12, 2011, regular Utility Commission meeting. SeCOnd by Mulhern. Ayes: Harmsen, Speich, Mulhern. Nays: None. Motion carried. OLD BUSINESS None. NEW BUSINESS 6a. Sanitar� Sewer Lift Station #1 Im,provements Executive Director Brotzlex started the discussion regarding the lift station improvements by apprising the Commission that the lift station had been renovated in 1987. There are no historical papers showing when the lift station was initially put in, however Staff knows that it's been in prior to 1972. Staff has been talkixig about the rehabilitation of this lift station for the past two yeaxs. Kevin Newman from WSB Associates, Inc. has been working with the maintenance personnel on this lift station and prepared a Technical Memorandum that summarizes the existing condition of the lift station and provides recommendations for improvements for the Utility Commission to peruse. Executive Dixector Brotzler introduced Mr. Newman. Mr. Newman gave an overview of the project he is anticipating, stating that review of the lift station by WSB was prompted by safety concerns Public Works staff have with certain features of the sta.tion. WSB was asked to investigate those concerns, evaluate costs for ixnprovements to eliminate the safety issues, as well as determine if there are other unprovements that should be made to the lift station. Lift Station No. 1 serves the downtown area and Central Park, including City Hall, the Public Works Facilities, and a lot of the businesses withixi the downtown area. Prior to the SPIRIT OF PRIDE AND PROGRESS 2875 145th Street West Rosemount, MN 55068-4997 651-423-4411 TDD/TTY 651-423-6219 Fax 651-322-2694 www.ci.rosemouni.mn.us UTILITY COMMISSION MINUTES December 12, 2011 Yenovations in 1987 the lift station included an above grade masonry building that was located over the below gxade concYete drywell and wet well. The masonry building housed the control panel and ventilarion equipment. The below grade dry well and wet well included intermediate/elevated concrete slabs that were for support and maintenance of equipment; pump motors in the dry well and a bar screen in the wet well. When the lift station was modified in 1987 the masonry building was removed and roof scuttles installed over the dry well and wet well for access. The intermediate concxete slabs were left in place. Only a portion of the intermediate slab in the wet well was removed for modifications that would allow installation of submersible pumps and removal of the bar screen. Kevin gave a brief description of improvements to the lift station that are recommended, starring from ground level and working down. Removal and replacement of the access hatches is recommended. The current hatches are not heavy duty and are not commonly used for access hatches for lift stations in current sta.ndaxds. The e�sting hatches stick 5 or 6 inches above grade creating a tripping hazard. On the inside of the existing hatches there are signs of severe corrosion and fatigue. There is also no safety grating inside the hatch opening. Replacement of the hatches with aluminum access hatches that include safety grating is recommended. Mr. Newman mentioned that a couple different options were evaluated for installation of the new hatches. The option xecommended is to expose the e�sting top slab, constructing a new cast-in place concrete slab over the existing top slab, and cast the new alutninum hatches into the new concrete slab. The hatches would be cast flush with the top of the concrete slab to allow easier snow removal. Replacement of the guide rails, which are used to remove the pumps, is recommended. The existing guide rails were constructed of galvanized steel and are showing visible areas of rusting and pitting at connection points. Replacement with staixiless steel guide rails is Yecommended. Removal of the elevated concrete slab in the wet well is recommended. The slab is no longer needed and poses a safety risk when maintenance personnel have to enter the wet well for cleaning, because it xequires that they walk under the elevated slab whexe they are no longer visible to someone from the access hatch. Removing of the slab will require the constructing of two beams to replace the lateral wall support that this concYete slab was designed to provide. With the slab removed the pump float cables can be move to the east side of the wet well, which won't require the need for maintenance personnel to enter the wet well to adjust or untangle to cables. Along with removal of the concrete slab in the wet well, removal of the concrete support for the old bar screen is recommended. The support is no longer needed and now just catches xags and other debris, because it is located right under the influent pipe. Replacing the wastewater pump impellexs with different style impelleYS to increase the capacity is recommended. Design guidelines for sanitary lift stations require that the lift station is capable of pumping the peak hour flow with the largest pump out of service. So with a two pump lift station, such as Lift Station No. 1, each pump should have the capacity to pump the peak hour flow, with the other pump out of service. The estimated peak hour flow to the lift station is 360 gpm. Based 2 UTILITY COMMISSION MINUTES December 12, 2011 on shop drawings and pump testing the e�sting pumps each have a capacity of appro�mately 300 gpm, falling short of the existing peak hour flow by 60 gpm. Records indicate that both pumps have had to run together for several minutes to keep up with peak flows. Removal and replace of the dry well access ladder is recommended. The existing steel ladder in the dry well is in very poor shape with severe rust and corrosion. Replacement of the existing ladder with an aluminuxn ladder is recommended. The existing area at the lift starion is grass with no space for parking or staging for repair or maintenance vehicles and equipment. Wet weather creates slippery and hazardous conditions making snow removal difficult along with no firm ground to place a tripod fox lowering someone into the wet well. So paving axound the site is recommended. The Coinmission members asked Mr. Newman quesrionsjconcerns that they had. The vent looked good when inspected. The new access hatches will include a surety system connected into the SCADA system to norify Public Works of unauthorized entry. At this time there aren't any other projects that this lift station could be linked to. After the failute at Lift Station #51ast yeax it was decided to check on the diffexent stations. Lift Station #1 has been on the maintenance personnel's radar for a couple years so Staff decided to start with this one. Initially they were just talking replacing the hatches and tearing out the intermediate sla,b. Going this route Staff will be able to srick the vactor tube from the jet truck in the wet well rather than manually raking out the sludge. Commission Member Mulhern wanted to make sure any metals used for the new ladder to the dry well axe compatible, which Mr. Newman assured them they would be. President Harmsen questioned the capacity of the pumps. Executive Director Brotzler assured him that Lift Station #1 has accounted for any development within the downtown district. Replacing the impellors is cost effective. President Harmsen also wondered if they had considered eliminating the dry well at all. Mr. Newman said that they hadn't considered eliminating the dry well, but had considered modifications to reduce the overall depth of the dry well. The modifications would be more expensive, because of the elevarion of the existing forcemain and the structuxal modifications that would have to be made to remove the existing elevated concrete slab and construct a new floor slab Generally Staff never has to go down into the dxy well. There axe two 4" discharge pipes, one from each pump, that connect into the 6" forcemain. A question was asked regarding the condition of the existing forcemain. Mr. Newman indicated that the forcemain was not inspected as it would require televising. However, a hydraulic analysis was perfoxmed and based on that analysis; it is presumed that the forcemain is in decent condition as the pumps are still pumping at close to original design capacity. This is a long range rehabilitation project. 3 UTILITY COMMISSION MINUTES December 12, 2011 MOTION b Mulhern to authorize 1) re aration of lans and s ecificarions; and 2) the Y p p P p solicitation of quotes for the Sanitary Sewer Lift Station #1 Improvements. Second by Speich. Ayes: Speich, Mulhern, Harmsen. Nays: None. Motion carried. PRESIDENT'S REPORT None. EXECUTIVE DIRECTOR'S REPORT 8a. PROJECT UPDATE Executive Director Brotzler humorously informed the Utility Commission there is an end in sight for the Quiet Zone project. At least Staff hopes it is as this has been the ongoing, never ending project. Work will be completed and another 21-day norice will be forwarded on to the Federal Rail Association (FR.A) by the end of the year. Hopefully by early January the City of Rosemount will have a Quiet Zone in pla,ce. Prestwick Place 2° and 3`� Additions and Connemara Trail have been the projects of the year. Connemara Trail advanced enough so the streets within the two new additions have only the final lift to be put down in the spring. The 2011 Street Improvements are complete. A public hearing was held foY the 2012 Street Improvements, which encompass Shannon Parkway from County Road 42 to 145`�' Street; 145` Street from Shannon Parkway to Cameo Avenue (paxking will remain on both sides of the road between Chippendale Avenue and Cameo Avenue), the bike route will be signed; and the Shannon Hills neighborhood. A smaller project with a lot of facets is Hawkins Sanitary SeweY Extension, which is out on the Continental Nitrogen property at the corner of TH 52/55. It is developer driven for Hawkins Chemical, Yocum Oil and Feed Products. Executive Director Brotzler handed out information on the fees for 2012 on water meter costs with and without an MXU. These axe the fees the builders pay on a building perxn.it for the water meter. Part of the purpose of bringing this to the Commission was to let them know the City is going to an IPERL versus a SRII water meter. These axe both Sensus meters which is what is mandated in the City Code. There is a slight cost increase, however the IPERL have a longer warranty life, better low level flow read and they are not noisy because the noisy meters are within the chamber of the meter and the IPERL doesn't have a chamber. Staff feels the positive outweigh the slight cost increase. T'he water usage report shows that water usage finally caught up in October. Executive Director Brotzler indicated he feels the reason for the usage is because of the good job the City did educating 4 UTILITY COMMISSION MINUTES December 12, 2011 the ublic on conservation and the new rates. OveYall the City didn't have a lot of calls Yegarding P the new billing structure. 8d. SET NEXT MEETING AGENDA FOR January 9, 2012 Nothing at this time, however the stormwater discussion will be coming back sometime in 2012. MOTION by Harmsen to adjourn. SeC011d by Speich. Meeting adjourned at 6:20 p.m. Respectfully Submitted, Cindy Do 'den Recording Secretary 5