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4.0. SR 02-08-1993 IkrL Lt. o. _ / f ~ ~ ~ ~ CONSUITING ENGINEERS · -~ ~_I Maier Stewart & Associates Inc. February 3, 1993 File: 230-151-80 Mr. Pat Klaers City Administrator City of Elk River 700 Dodge Avenue NW Elk River, MN 55330 RE: ELK RIVER WWTP IMPROVEMENT PROPOSED DESIGN FLOW AND NEW EFFLUENT DISCHARGE STANDARDS Dear Mr. Klaers: . The meeting with the City Council on January 25, 1993, has suggested a higher wastewater treatment capacity than 2.2 million gallons per day (MGD) that was previously proposed for the current plant expansion. We have extended the service area, as advised by the Council, toward the east and south regions shown in Figure 1. The U. S. Census Bureau and State Demographer's Office predicted the population for the Year 2000 to be 15,000-18,000. This means about 3-5 percent of annual growth from the population 11,700 of the Year 1991. Using the 5 percent annual growth rate, population for the Year 2012 is projected to be 32,600 in the City. Based on the projected population, the sewage flow at the Year 2012 is projected as follows: Year 1991 - Total Population Serviced Population Average Wet Weather Flow (MGD) 11 ,700 5,414 0.67 . Year 2012 - Total Population Population Increase Since 1991 Existing Unsewered Becomes Sewered (Estimated) Serviced Population Increase Sewage Flow (gallons per day per capita, including Industrial and Commercial) Sewage Flow Increased (MGD) Infiltration/Inflow Increased (MGD) Average Wet Weather Flow (MGD) (0.67 + 2.19 + 0.13) Design Flow (MGD) 32,600 20,900 1,000 21,900 100 2.19 0.13 2.99 3.00 1959 SLOAN PLACE, SUITE 200, ST. PAUL, MINNESOTA 55117 612.774-6021 9800 SHELARD PARKWAY, SUITE 102, MINNEAPOLIS, MINNESOTA 55441 612-546-0432 · Equal Opportunity Employer . . . Mr. Pat Klaers February 3, 1993 Page Two The proposed design flow (3.00 MGD) would be about 4.5 times the existing sewage flow (0.67 MGD). In regard to the wastewater treatment plant effluent discharge standards, we have been advised by the Minnesota Pollution Control Agency (MPCA) that the plant's effluent is currently discharged to the Mississippi River, which is classified as "Outstanding National Resource Water"; therefore, the Nondegradation Regulation applies. Under this regulation, the total mass loadings of Carbonaceous Biochemical Oxygen Demand (CBOD) and Total Suspended Solids (TSS) from the treatment plant to the receiving water should not exceed the loading rates stipulated in the current permit. As the wastewater flow increases, additional treatment is required to further lower the effluent CBOD and TSS concentration. The existing plant is permitted 1.04 MGD with 25 mg/l CBOD (mass loading 98.3 kg/day) and 30 mg/l TSS (mass loading 118 kg/day). When the sewage flow is increased to 3.00 MGD, the effluent CBOD and TSS must be reduced to 8.67 mg/l and 10.40 mg/l respectively in order to comply with the mass loadings requirement. To achieve such an effluent quality, it will cost more to treat every gallon of wastewater than it does now. For the City of Otsego, MPCA indicated verbally that 25 mg/l CBOD and 30 mg/l TSS may be their effluent limits if they construct their own wastewater treatment plant. When this issue is discussed, the City of Otsego should be made aware of the more stringent treatment and higher treatment cost at the Elk River Plant. Whether it would be economical to deliver sewage to Elk River for more extensive treatment or to build their own treatment plant to meet a probably less stringent effluent limit should be reassessed. We would like to continue the discussion with the City Council relative to design flow as soon as possible so we can proceed with the process design. If you have any questions or comments, please feel free to call. Yours truly, MAIER STEWART & ASSOCIATES, INC. ~~~(itU T;;;;;.~~~r, P.E. bO;M/f/ Bill Chang, P .E. BC:tp 151-0304.fOO .(" ,', Jt~ it, Ii: IJ I ~f~ (l I _ . / 1 _,.,0 ., , (~. .",) "JJI.I" , I.." \/' ,y '~"""'. r",' .....- L, . --=--,.~-, I ! v A1 I "-J~..,j ~~Lt: " ~.\ " D f7\Jln"~~"~i =-!t!rl!= ~ll I ~ ,1\'\Yf'I./ ~.--''-''l IT l " ...J I " J: 11;;t.~~ ' . 2 -,/"'.rr '['1!:J,,~ r :,." .~ LLJ~.~, I""; 11'1// I t--'lu ~r J _ I ,I ;/,. ~1~ ~. I + I t ~ I f I ;.-/<J ~ r r~ ._n..!!\..!!...",. ;A~'", I I (> : )Jl~~i<, lml ,~;~U /' r-- "!i';'~t!. . r " . '\ I '. Jt ~ 11 . .~: __J_n ~ T1 n , -II _~-' [0'-.0 r ~ . ILlU, lt1\ \j I \ '\ . 1. . .. I ., . , Tl~ll I . . '/.1, /' ,I;. li. " "",". "i1J" J' JJH , "".. :y, I ~ ..:- I . I f11a lJ" -,~ ~\' ->" i;';t I,ll ~'tJ *' ,;r M 'J -'m, ll.!=~..,~ 111 '4JU;ir,~~~ I~r .1 A1 II ':.IT ~:~, A1 '11' '~~~:i' ' ], ;-;r' ~i'~ ~I i,~:, ~ l )~" :=b;1 ~J, ~ - R~~ ~~ , ~~1!,; I) Y 1 . 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February 8, 1993 File: 230-151-80 Mr. Pat Klaers City Administrator City of Elk River 720 Dodge Avenue NW Elk River, MN 55330 RE: NON-DEGRADATION RULES FOR OUTSTANDING RESOURCE VALUE WATERS Dear Mr. Klaers: As you know, the reach of the Mississippi River that receives the City's treated effluent has been designated an "outstanding resource value" water. In fact, the entire reach of the Mississippi River from St. Cloud to the Anoka City limits has been designated an "outstanding resource value" water. Non-degradation rules apply to these waters. In simple terms, the non-degradation rules state that there shall not be an increase in the total pounds of biochemical oxygen demand (BOD) associated with a municipality's effluent discharge. Elk River's current NPDES permit allows a discharge of98.3 kilograms (216.84 pounds) of BOD . per day. The 216.84 pounds was determined according to the following equation: lb. BOD/day = BOD concentration in mg/l x flow in millions of gallons per day x 8.34 Filling in the permitted BOD concentration of 25 mg/l and the permitted flow of 1.04 MGD completes the equation: lb. BOD/day = 25 mg/l x 1.04 MGD x 8.34 = 216.84 If the total pounds of BOD per day cannot increase, it becomes apparent from this equation that as flow increases, the permissible BOD concentration must decrease. The City Council has indicated a desire for up to a 3 MGD wastewater treatment facility. An increase from roughly 1 MGD to 3 MGD will result in a permissible BOD concentration of approximately 9 mg/l (25 mg/l -:- 3). Achieving this or any level of BOD removal over approximately 1.75 MGD will result in a more expensive wastewater treatment facility (WWTF). There are some alternatives to constructing a WWTF to meet this more stringent BOD concentration. These alternatives include: . Construction of a controlled discharge treatment facility (stabilization pond system) . · Construction of a land application treatment facility. 1959 SLOAN PLACE, SUITE 200, ST. PAUL, MINNESOTA 55117 612-774-6021 9800 SHELARD. PARKWAY, SUITE 102, MINNEAPOLIS, MINNESOTA 55441 612-546-0432 . Equal Opportunity Employer 151-080l.feb . . . Mr. Pat Klaers February 5, 1993 Page Two · Construction of a WWTF to meet current effluent limitations (BOD = 25 mg/l and TSS = 30 mg/l) and an effluent pipeline to the point that the Mississippi River is no longer designated an "outstanding resource value" water (Le., Anoka City limits). · Obtaining a variance from the non-degradation rules. Unfortunately, none of these alternatives is particularly viable as will be explained below. A stabilization pond system must store wastewater flow for a 180 day period. For a 3 MGD flow this would result in over 400 acres of wetted surface. With dikes, buffer zones, etc., figured in, approximately 600 acres of land would be required. This land requirement, in combination with the expense of sealing the anticipated permeable soils in the Elk River area, would result in a high cost to construct a stabilization pond system. Land application is not a particularly viable option either, because even more land would be required. Also, a land application system would require even more storage than would be required for a stabilization pond system. Construction of a WWTF to meet current effluent limitations (BOD = 25 mg/l, TSS = 30 mg/l) and an effluent pipeline to near the Anoka City limits is not a viable alternative because of the cost of the effluent pipeline ($4 million +). The final alternative, that of obtaining a variance from the non-degradation rules, would result in the least cost WWTF, both from a capital cost standpoint, as well as an operation and maintenance cost standpoint. Gary Rott of the Minnesota Pollution Control Agency states in the attached letter, "This rule (non-degradation) makes it very difficult for a discharger to prove that the mass loading of his existing discharge should be permitted to increase." Although this statement is discouraging, MSA feels that further research into the possibility of obtaining a variance is warranted. Over the 20-year design life of the expanded WWTP, the extra cost (capital and operation and maintenance) of a 9 mg/l BOD WWTF over a 25 mg/l BOD WWTF will be in excess of $1 million. Please let me know if you agree that MSA should conduct the research on a variance from non-degradation rules. Sincerely, MAIER STEWART & ASSOCIATES, INC. Bl!!t~ . . . _ / f ~ . ~ ~ CONSULTING ENGINEERS ~_I Maier Stewart & Associates Inc. February 5, 1993 File: 230-133-10 Mr. Pat Klaers, Administrator City of Elk River 720 Dodge Avenue NW Elk River, MN 55330 RE: JACKSON/SCHOOL/169 FEASffiILITY STUDY Dear Mr. Klaers: Attached are ten copies of the Jackson/School/169 Feasibility Study prepared in February 1992. These are for backup information for the new City Council members. In reviewing this study, we would offer the following comments about it: 1. This feasibility study was presented to the City Council on March 9, 1992, but no action was taken. 1L an overall feasibility study is prepared for the Elk Park Center proposal which includes internal improvements, trunk utility improvements from this study and external road improvements from the traffic impact study, tillm no action may ever need to be taken on this study because it will be superseded by the project specific study. 2. The exhibits contained in this study were based on the original site plan for Elk Park Center. Therefore, they do not accurately reflect the most recently revised plan for the development of that area. 3. Through discussions with the City Council, the developers of Elk Park Center, and a joint meeting with the City Council and Utilities Commission, the consensus has been that the water systems improvements should include an elevated tower, well, and water treatment. 4. The -high pressure water system would provide service to Deerfield 3rd and 4th, Royal Oaks Ridge, Hillside Estates, and Cherryhill Bluffs, thus eliminating the need for the water booster station. However, the booster station would remain in service as a backup in case of a well failure. 1959 SLOAN PLACE. SUITE 200. ST. PAUL, MINNESOTA 55117 612-774-6021 9800 SHELARD.PARKWAY. SUITE 102. MINNEAPOLIS, MINNESOTA 55441 612-546-0432 . Equal Opportunity Employer . . . Mr. Pat Klaers, Administrator February 5, 1993 Page Two If you have any questions or would like me to present this report to the City Council, please call. Sincerely, MAIER STEWART & ASSOCIATES, INC. spr~ Terry J. Maurer, P.E. TJM:tp 133-0507 .feb _ / } ~ ~ ~ _~ J CONSULTING ENGINEERS · .",""- Maier Stewart & Associates Inc. February 10, 1993 File: 230-080-10 Mr. Pat Klaers, Administrator City of Elk River 720 Dodge Avenue NW Elk River, MN 55330 RE: EAST HIGHWAY 10 FEASffiILlTY STUDY Dear Mr. Klaers: . Enclosed are ten copies of the East Highway 10 Feasibility Study. These are for informational purposes for the new City Council. This study was authorized in 1989 during the discussion relative to city sewer and water to serve the proposed Americ Inn. The draft study was completed in March 1990. When the Americ Inn project moved forward without the need for city utilities this study was put on hold. Other factors that have kept this study on hold are the Focus Area Study, Community Center Task Force and City Hall issues. Therefore, these studies are still in draft form as indicated by the preliminary stamp on the front cover. Please let me know how you would like us to proceed with this issue. Sincerely, MAIER STEWART & ASSOCIATES, INC. T~~ TJM:tp Enclosures 08~06.feb . 1959 SLOAN PLACE. SUITE 200. ST. PAUL. MINNESOTA 55117 612-774-6021 9800 SHELARQ PARKWAY. SUITE 102, MINNEAPOLIS, MINNESOTA 55441 612-546-0432 . Equal Opportunity Employer . . . or ~ 1113111'1-/1 ...j"4 a: w f- Z~ wg O~ z ~~ a: a: <(~ a. a: ~ -J ~W -I W ~ e;j ~~i~ ~15~ll' ~fi~~ ><;r:ilj Iilue i ~ ~ In ...1 ll!j~ 01 HOd YlllY '1.0UN.,." '.JAII 111) IIl!Hl:l )Il1Yd )I1l J!~ . I.... IL .....t-:::-:-:: , , , , \ , \ \ \ \ , , , -...___1 () ~ ~ EB i [' ~;