5.2. SR 01-11-2011 - Laserfiche WebLink

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10) WWTF Pumps and Controls Over the past months the crew at the WWTF have been experiencing some operations issues with the final clarifiers and sand filter at the plant. The problem consists of a layer of sludge that has built up in the final clarifiers. This sludge then affects the effluent water by sending additional solids to the final sand filters before leaving the plant. The additional loading entering the sand filters has caused some plugging and ultimately required replacement of some sand media. The crew has exhausted methods to remove the sludge blanket from the final clarifiers. This condition is taking large amounts of staff time and requiring the replacement of the sand media in the filters. In addition if the problem is left uncorrected, the effluent water leaving the plant may exceed limits set by the MPCA for total suspended solids (TSS) by this summer. This will result in a violation letter and corrective action order from the MPCA. In working with Bill Chang, the plant design engineer from BDM, we have developed a solution to correct the problem. The solution includes adding two pumps, modifying some plumbing, and controls on the sludge discharge lines leaving the final clarifiers. This will allow the operations staff to remove the sludge blanket from the clarifiers and lower the ultimate loading on the sand filters. We have estimated the costs for completing this work will be around $80,000 and come from the Sanitary Sewer Fund. To keep costs down the City crew will be completing the required demolition and disassembly work. Gary Leirmoe has solicited two quotes for the remaining installation of pumps, plumbing, and completion of the controls work. I will bring the quotes forward for consideration at the January 10, 2011 City Council meeting. Schedule Upon approval, we will direct the selected contractor to begin the work. There is a long lead time to order the pumps and controls and thus we need to have the contractor order them now to allow for the installation by the end of Apri12011. 11) Intersection Enhancements We have been in discussion with MNDOT who will be completing a pavement rehabilitation project along TH 169 in 2012. In our discussions with MNDOT we expressed the desire to incorporate a designated right hand turn lane at the intersection. of Jackson Avenue and TH 169 for east bound to south bound traffic. MNDOT was going to complete a survey of this area to identify the existing conditions and right-of--way limits. We are also considering the extension of the right turn lane at the intersection of Main Street and TH 169 for east bound to south bound traffic. Similar to the improvements we completed along Main Street in the opposite corner of the intersection during 2010, we would extend the turn lane to the west to provide additional stacking. N:\Public Bodies\Ciry Council\Council RCA\Agenda Packet\1-10-2011\Engineer Update.docx