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CITY COUNCIL WORK SESSION <br />DRAFT <br />1 CITY OF LINO LAKES <br />2 MINUTES <br />3 <br />4 DATE : March 7, 2022 <br />5 TIME STARTED : 6:15 p.m. <br />6 TIME ENDED : 7:45 p.m. <br />7 MEMBERS PRESENT : Councilmember Stoesz, Lyden, Ruhland, <br />8 Cavegn and Mayor Rafferty <br />9 MEMBERS ABSENT <br />10 Staff members present: City Administrator Sarah Cotton; Community Development <br />11 Director Michael Grochala; City Engineer Diane Hankee; Director of Public Safety John <br />12 Swenson; City Clerk Julie Bartell <br />13 <br />14 (5:30 pm) The Rookery Activity Center (visit facility) <br />15 <br />16 1. Water Treatment Pilot Study, Greg Johnson and Ursinio Puga of WSB and <br />17 Associates — Mr. Johnson reviewed the written report noting that in 2021 the council had <br />18 authorized WSB to complete the pilot study. Mr. Johnson added that the biological <br />19 filtration process being recommended is already being used effectively in several other <br />20 cities and has been utilized in Europe for decades. Mr. Johnson and Mr. Puga reviewed <br />21 a PowerPoint presentation that included information on: <br />22 <br />23 <br />- Raw Water Quality — parameters for monitoring the water for pilot study; <br />24 <br />focus on removing iron, manganese and ammonia from water; dissolved <br />25 <br />oxygen and orthophosphate will also be discussed; <br />26 <br />- What is Biological Filtration — microorganisms are already in the water and <br />27 <br />need optimum conditions to get to the level to remove; other biological <br />28 <br />filtration plants in the state; <br />29 <br />- Conventional Filtration vs. Biological Filtration — comparison table; chemicals <br />30 <br />are reduced by utilizing biological process; the rest of the process is same <br />31 <br />minus some of the chemicals; <br />32 <br />- Pilot Study Goals and Objectives; <br />33 <br />- Pilot Plant Setup and Operation — view of pilot study testing machine used at <br />34 <br />Well No. 6; two filter medias were compared; trailer was used for testing; <br />35 <br />- Pilot Study Results — Found orthophosphate adequate; graph showing aeration <br />36 <br />requirements; oxygen is added in the form of natural air; iron isn't a big goal <br />37 <br />because it is already okay; ammonia results also graphed and reviewed; <br />38 <br />- Financial Analysis — both treatment options include the same steps of treating <br />39 <br />the water; with biological treatment chemicals are greatly reduced; graph <br />40 <br />comparing costs for chemicals (inflated numbers used); Mr. Puga noted <br />41 <br />information from another city that has already changed from conventional to <br />42 <br />biological filtration and who experienced savings because of the rise in supply <br />43 <br />costs; <br />44 <br />- Conclusions; <br />1 <br />