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IV. SEPTIC SYSTEM OPERATIONAL PARAMETERS AND COMPONENTS The plan set, the operational parameters and the operational components of the wastewater treatment and disposal system for this project will be provided by the engineer -of -record, Mr. Paul Schneider, PE. V.P. of Siegfried Engineering, Inc. V. CONCLUSIONS AND RECOMMENDATIONS NLS§ 4.1. The nitrate loading calculations show the resultant effluent from the proposed project will theoretically possess a nitrate -nitrogen concentration well below the Federal nitrate Maximum Contaminant Level (MCL) of 45 ppm as nitrate or 10 ppm nitrate as nitrogen. A total nitrogen concentration that was used in the calculations was derived from the actual sampling of effluent from a septic tank installed for the Holly Commerce Center in 2017. This total nitrogen concentration provides a very accurate representation of future nitrogen loading from the project since it is assumed that the E&E Building will operate under similar conditions as the existing Holly Commerce Center. The septic tank effluent analyses were determined to be very high in nitrogen concentration at 146 mg/L TKN. This high nitrogen concentration may be attributable by a lack of a dilution effect caused by waterless and low flow fixtures. By conserving water with these fixtures, an apparent increase in nitrogen concentration has resulted. However, the total nitrogen contribution from the proposed sanitary sewer septic system to serve the subject property remains under the nitrate MCL. And of significance is that by developing this Parcel, thus creating impermeable surfaces of buildings, dock areas, parking lots, etc., this will "cap" the soil surface and prevent further migration of nitrate within the high nitrate laden soil from entering the groundwater due to rainfall. SSS§ 5.4, 6.8. The shallow soils underlying the proposed effluent disposal area show a slow but acceptable permeability at 50 min/in, translating to an acceptance rate of 0.311 gallons/ft2/day. Uniformly applying the effluent through equal distribution by laying the perforated drain pipe level over the entire filter bed area will allow optimum effluent management by the receiving soils and prevent soil saturation throughout the vadose zone. Taking only nitrate -nitrogen into account (not TN, TKN or NH4); we find the following: The soil nitrate -nitrogen concentration was determined to be 189 ppm at the 24" depth, approximately 0.8 ft above the water table. The water table concentration of nitrate was measured at 85 ppm. This nitrate concentration must be converted to nitrate -nitrogen for comparison purposes with the soil concentration: 85 ppm nitrate = 19 ppm nitrate -nitrogen. Therefore, a decrease in nitrate -nitrogen concentration from 189 ppm in the soil to 19 ppm in the top water table occurs in a distance of approximately 1.5 ft; a 90% decrease. This decrease can be attributable primarily to denitrification because of anaerobic conditions within the phreatic zone along with a carbon substrate, and the lack of sufficient alkalinity. Page -9- Chesney Consulting