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June 11,2003 Job Number:LG03-137 Page 10, stream)was assumed to be 51.8 mg/L-N. The leach field denitrificaiton was assumed to be 35 percent. Please refer to Table 8 for a summary of the results of the nitrate loading equation. Please.note the variable Nc represents the-average, long-term nitrate concentration of percolating water.for . the site from rain water and treated domestic waste water. Hantzsche and Finnemore (1992) indicate that the nitrate concentration of the aquifer may"build up" to the Nc level in the long term. Table 8. . S mma of Nitrate Mass Balance ance Analysts. Scenario Result Acres Average Daily Effluent Leachfiel Deep c * ' ((Nc) (A) Flow(Q) . Concen- d Percolation of (Table 6) tration(Nw) Denitri£- Rainfall(R) ter---- ` cation.(d) (Plate 4) Standard Sept9.9 mg/L-N 0.W2 27.2 gpd 51.8 mg/L-N' 35% 1.07 in 5 stem Plate 5 Maximum contaminate-level-wCL)for Nitrate in drinking water is 10 mg/L N. 7.0 CONCLUSIONS AND RECOMMENDATIONS r In conclusion, a satisfactorypercolation rate was achieved on the property. The depth to ground water on June 3, 2003 was found to be 9.5 feet- The nitrate levels measured in the onsite well was 76 mg/L-NO3 (or 16.8 mg/L-N). The Environmental Protection'Agency maximum contaminate level for drinking water for nitrate is 45 mg/L as NO3 (or 10 mg/L-N). The presence of coliform was not detected in the water sample. . The'nitrate loading analysis has shown that the use of a septic system may not cause a build up of nitrogen-in the aquifer above the maximum contaminate level for nitrogen of drinking water which is 10 mg/L.-N. The result of the analysis indicates nitrate level (Nc) for the property is 9.9 mg/L-N.. 'This .. level assumes low water use by.the five (5) customers or Iess per day, essentially 1.7 gallons per flush per customer visit and 13 gallons per-day for one (1) employee. m addition, 35 mg/L- N was assumed to be the typical concentration for septic waste using average na Twaer. Since the well water was tested and shows 16.8 mg/LN(or 76 mg/L-NO3) nitrate, the Nw level was increased to 5 1.8 mg/L-N for total nitrate to reflect this condition. X w