08-22-2022 City Council Packet - Laserfiche WebLink

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Understanding The City of Lino Lakes is planning to construct a new 8.6 million gallons per day (MGD) iron and manganese Water Treatment Plant (WTP) to treat Wells 1, 3, 5, 6 and future wells following a traditional design -bid -build method. All four wells exceed the Minnesota Department of Health's recommended health risk limit (100 ppb) for manganese for infants. In 2020, the city prepared a Feasibility Study for the purpose of selecting the preferred site, developing the preliminary design concepts for the WTP including the selection of treatment processes, developing floor and site plans, and preparing preliminary cost estimates. In 2021, the city completed a biological filtration water treatment pilot study that successfully treated the iron and manganese in the City's highest producing manganese well without feeding chemicals The city has requested this proposal from WSB to provide professional engineering services to complete the final design, to prepare plans and specifications, to assist with bidding the plans and specifications, and to administer and observe the construction of the proposed WTP. Water Quality and Treatment The City of Lino Lakes proposed water treatment plant will need to provide manganese free water in addition to removing other secondary contaminants. The design capacity of the plant should be high enough to meet the city's projected maximum day demands or be designed to be expanded in the future. The plant should be designed to treat iron and manganese biologically with aeration and gravity filtration in addition to feeding chlorine for disinfection, and fluoride for dental care. The analysis of the water treatment plant will include, but not be limited to, estimated construction costs, flexibility of the system to treat additional elements as drinking water standards change, water chemistry changes or demand necessitates, the ability of the system to effectively and efficiently remove manganese, iron, and other contaminants from the water supply, ease of the operation of the system (manpower needed, availability of replacement parts and materials), the discharge of the waste products, and the ability of the plant to be modified in the future. This will be a comprehensive review during the preliminary design phase and recommendation of the best treatment facility to meet the current and future needs of the city. The manganese and iron in the city's well water could be treated without chlorine and potassium permanganate with biological filtration as successfully piloted. In addition, the disinfection byproducts (Total Trihalomethanes and Total Haloacetic Acids) that are formed in the city's water when chlorine reacts with the natural organic matter could be totally eliminated with biological filtration. A Proposal for Design, Bidding, and Construction Administration for a Water Treatment Plant for City of Lino Lakes Project Understanding & Approach 2