Agenda Packets - 1985/06/24 - Laserfiche WebLink

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SUE&" TKDA Ill U"fill 1,'I aryl, d', :r ilia lI ' irJ..bP.urtll Alm I'll. AN fill Ip ALAI hANK 111111111f1r. ENGINEERS ARCHITECTS PLANNERS n,�ran .AlrAM1 snit. r•.Im April 10, 1985 Mr. Steve Thatcher, P.E. Director of Public Works/Community Development City of Mounds View ,} , 2401 Highway 10 ` Mounds View, MN 55112 Re: Pilot Plant Study - Phase 2 Well No. 3 Mounds View, Minnesota Commission No, 7848 Dear Mr. Thatcher: Review of the results of SercoIs pilot plant operation on Well No. 3 water, conducted using potassium permanganate and greensand filter media, Indicates to us that the concentrations of Iron and manganese In the water are too high for satisfactory water treatment using the existing filters In Plant No. 1, even with greensand modification. Manganese residual concentrations approaching those recommended for trouble -free municipal water quality Just were not achievable. Therefore, the City has three (3) remaining options with regard to Well No. 3 as we view It: 1) Conduct pilot plant studies to determine if ozonation will yield a suitable treated drinking water 2) Consider lime softening to remove the Iron and manganese with the other mineral constituents 3) Abandon Well No. 3 as a source of water for the City Although we belleve that ozonatlon will likely reduce the Iron and her or not tmaanese levels he tt continued use No. 3,he desired and the atreatment necessary tions, we question wt trender Its water suitable, Is Justified. Well No. 3 Is a relatively shallow well, thus more vulnerable to contamination. In addition, Well No. 3 cannot be deepened to draw upon lower aquifers because of Its limited present diameter and because Its drawdown would Interfere with Well Nos. 1 and 2, which are already deep wells. Under the circumstances, we recommend the following course of action for tho City: 1) Conduct pilot plant studies for treating Well No. 3 water with l ozone. 2) Conduct similar tests on the water from Well No. 4.