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r � November 15, 2010 � Brian Palmer 1190 Lyman Avenue � Wayzata,MN 55391 Subject: Onsite Wastewater System Design � Sub'ect Pro : 1190 L an Avenue• Ci of Orono Minnesota J P�3' Ym � tY , � Introduction � The subject property contains an existing house, driveway, shallow well, and Onsite Wastewater System (OWS), as shown on the Certificate of Survey completed by � Gronberg & Associates, Inc. located in Appendix A and on Figure 1. The homeowner intends to make improvements, additions, and needed repairs to the house and is in need of upgrading the OWS (a.k.a. septic system). The existing OWS is located west of the � house and will be abandoned in accordance with City of Orono ordinances. • Design Parameters for Proposed OWS: � o Number of Bedrooms for the design: Four(4)Bedrooms ■ Design Flow: 600 Gallons per Day o Expected Wastewater Characteristics: � ■ Influent to Septic Tank BOD = 150-225 mg/L TSS = 125-180 mg/L � Oil and Grease= 10-30 mg/L Fecal= 100,000-1,000,000 fcu/100m1 � Soil Conditions The Hennepin County Soil Survey (Appendix B) indicates the site is underlaYn by a � Lester-Kilkenny Complex formed in calcazeous loamy glacial till deposits. These soils generally have a depth to seasonally saturated conditions at less than three feet. The soil descriptions completed from the three soil borings (Appendix B) in the drain field area � depicted on Figure 1, indicate evidence of seasonal saturation (i.e. redoximorphic features) at 30-32 inches, requiring the installation of a "mound" drain field. The mound system is being designed with a one foot sand lift to ensure a three foot vertical � separation distance will exist to seasonal saturation after construction. Two saturated hydraulic conductivity tests were performed in the drain field area with a � constant compact head permeameter. The results of the tests (Appendix B) indicate a rate of water movement into the soil of approximately 5-10 minutes per inch at the depth tested. � � 1