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Detention Time Calculation: Detention Time=2,000 gal proposed tank capacity x 0.70(30%volume lost to sludge/scum accumulation) 1.9 (Peaking Factor)x 560 gals/day (Total ADF) Detention Time= 1.3 days. The minimum acceptable detention time is 1.0 days. Therefore, a 2,000 gallon septic tank is suitable for sufficient detention time and a 10%to 20%reduction in N concentration. , The septic tank excavation was completed in the early Fall. Winter rains have washed soil down into this excavation. A backhoe must be used to clean out this soil inflow to the proper depth and elevation. The top of the tank must be as close to finished grade elevation as possible. Workers must not be allowed into this excavation without proper shoring as determined by a knowledgeable professional. Primary Disposal Area - Chambered Leachlines Mr. Radrigan is proposing to install Infiltrator®Leaching Chambers within the leachline trenches which were also excavated last Fall. Total leachline length=492 ft. As with the septic tank excavation, winter rains have washed soil down into the trenches and have caused a "silt-over" effect. These trenches must be re-excavated, preferably by hand, to remove the soil that has washed in, and prepare the native soil at the originally excavated depth to receive the organic sawdust/compost material discussed below. 100% Replacement Area The 100%reserve/replacement a' outlined in red ink on the plans found in Appendix C. It consists of an approximatecan 1 filter bed area that is approximately 22 ft N-S and 72 ft E-W for a total square footage of 1671 s . The attached NOTES to the Site Plan illustrating the primary and replacement areas, i ica a construction details of the septic system,particularly the 100% replacement area. Nitrate Loading Mitigation Measures Through extensive scientific research, it has been proven that rapid nitrification occurs within the top one-to-two inches of nitrogen receiving soils.' Three critical environmental factors that impede and can prevent this nitrification of the ammonium fraction of the effluent are anaerobic conditions, alkaline pH of the soil (enhanced by O.M. addition), and a carbon to nitrogen ratio (C:N)of the soil above 20 (also enhanced by the addition of O.M.). The Infiltrator Chambers proposed to be installed offer significant benefits by creating anaerobic conditions in the soil as the effluent dribbles into the Chambers causing saturated and thus anaerobic soil conditions. Page 4 of 13 Chesney Consulting