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CFAsferenced, in conjunction with taking soil samples from.the backhoetest pit,a water table e was retrieved for. analyses of Nitrate, Total Dissolved Solids (TDS), pH and Total Alkalinity. The nitrate concentration was measured to be 23 mg/L. The TDS is high at I346 mg/L ! and T)2.3, tal Alkalinity,is 405 mg/L,which is discussed below. NLS§ SS§-4.3, 4.4, 4.5:- There is no electricity to the referenced well, and therefore, could not beed. lation of Alkalinity Nitrification Requirement for q t fficatian The nitrate-nitrogen loading estimation-on Page 14 is contingent upon the-environmental factors required for nitrification to occur.--These conditions include soil pore-space oxygen content, soil temperature, pH, electrical conductivity; organic-matter, cation exchange capacity, and alkalinity. Alkalinity in wastewater effluent is derived from the anticipated well water supply in addition to the introduction of wastes: Nitrification consumes approximately 7.1 mg of alkalinity for every mg of ammonia-nitrogen (NH4-N) oxidized. Nitrification of the average Total Nitrogen (TN) concentration of 31 mg/L, as determined on Page 12 would require: 31 mg/L NH4-N x 7.1 mg CaCO, =220 mg/L alkalinity. The alkalinity in the receiving water table is presently 405 ppm, so sufficient alkalinity exists which may theoretically retard nitrification to an indeterminable degree. This may also be contributing to the relatively low nitrate concentration.in the water table. Mounding Analysis Reference is made to the encountered groundwater from.the backhoe test pit at 9.5 feet below existing grade. The depth'to the water table is comparatively shallow which may induce a phenomenon known`as a"mounding effect.':'. This may occur when percolating effluent encounters the water table, or restrictive stratum.and cannot disperse_laterally in a certain time frame. Consequently; a mound forms under the disposal field creating saturated flow conditions and decreasing the distance the effluent must travel under unsaturated flow for effluent treatment to occur. An equation developed by Finnemore and Hantzsche (19$3) is used below to predict the long-term maximum rise of the mound:_ . h =N +Zm=2 where: h =distance from boundary to mid-point of the long-term mound;in ft H =height of stable groundwater table above impermeable boundary, in ft Z.= long-term maximum rise of the mound, in ft Substituting known and estimated values for the variables, we find the following: H =The height of stable groundwater above an.impermeable boundary is estimated to be 40 based upon the`. depth to the on-site well and measured standing water depth in the backhoe test pit. Therefore, it will:be . assumed that a boundary exists at-H =40 ft. Long-term maximum rise of mound is estimated at 0.5 ft. Therefore, h =40+(0.5 2)=40.25 Zn CAC! 4 4 Y l:Kh)0.5n Sy �.�.o.sa Chesney Consulting x