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October 7, 1999 <br /> Job Number: 599226 <br /> Page 7 <br /> VII. NITRATE LOADING STUDY <br /> A build up of nitrates in the upper ground-water zones can cause a temporary blood <br /> disorder in infants called methemoglobinemia(blue baby). Serious and occasionally fatal <br /> poisonings in infants have occurred following the ingestion of water containing nitrate <br /> concentrations greater than 10 mg/1 nitrate as N or 45 mg/l nitrate as NO3. The units of nitrate as <br /> used in the mass balance equation are nitrate-N with a maximum drinking water contaminate level <br /> of 10 mg/l. <br /> A nitrate loading analysis is used to estimate the concentration of nitrate-N of the septic <br /> effluent and rain water percolate before mixing with ground water. The analysis is based on a <br /> simple mass balance formula which takes into account soil denitrification, rain fall, and the <br /> proposed waste quantity and waste nitrate level. Assumptions and calculations for the analysis <br /> are contained on Plate 8 and Plate 9_ <br /> Denitrification is the biological process in the soil whereby certain bacteria utilize the <br /> oxygen in the nitrate(NO3) and release nitrogen gas(N2)to the atmosphere. The denitrification <br /> ` factor is expressed as a percentage and the normally accepted range is 10%to 25% . Areas with <br /> higher clay content, moist soil conditions, and organic material denitrify about 25% or more but <br /> areas with higher sand content are estimated to denitrify about 10%. Due to the presence of gray <br /> clay material in the shallow soil column soil column examined, we estimate the denitrification <br /> factor be about 25 %.ti IX56P75E Ah}dtaup YP <br /> In our analysis to determine the nitrate concentration,the anticipated occupancy(persons <br /> per day) and water use computation factor(gallons per person) are presented in the following <br /> ` table for the various buildings of the phased development: <br /> OSGI <br />