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WS-1 <br />WORK SESSION STAFF REPORT <br />Work Session Item No. 1 <br />Date: March 7, 2022 <br />To: City Council <br />From: Rick DeGardner, Public Services Director <br />Michael Grochala, Community Development Director <br />Re: Water Treatment Pilot Study <br />Background <br />The Minnesota Department of Health tested the City's manganese levels in each of the City's <br />wells as part of the EPA Unregulated Contaminant Monitoring Rule 4 (UCMR4). The water <br />quality testing data from MDH indicated that five of the City's six wells exceed the maximum <br />recommended manganese level for infants, and three of the wells exceeds the maximum <br />recommend level for adults and children. <br />On June 14, 2021, the City Council authorized WSB to complete the Water Treatment Pilot <br />Study to verify the effectiveness of biological filtration to remove manganese, iron, and <br />ammonia from the City's well water. The purpose of the study is to provide the City with critical <br />information that is required to design and size a water treatment plant to address the high <br />manganese and iron levels in its drinking water. <br />The attached report recommends construction of a conventional gravity filtration system using <br />biological filtration with an initial treatment capacity of 6,000 gallons per minute (gpm). <br />Biological filtration is promoted by the Minnesota Department of Health and is currently being <br />used by the cities of Minneapolis, St. Paul, St. Cloud, and other communities in Minnesota to <br />effectively treat their drinking water. Biological filtration could potentially save the City almost <br />$1 million in chemical costs and save millions of gallons of water over the first 20 years of plant <br />operation. <br />The next steps that were previously identified included completion of the utility rate study and a <br />water treatment pilot study. The Utility Rate Study was completed by Baker Tilly and accepted <br />by the City Council on May 10, 2021. Staff is now proposing to move forward with the design <br />phase for the proposed water treatment plant. <br />Requested Council Direction <br />Information only. <br />Attachments <br />1. Water Treatment Pilot Study Report <br />