SR0084207_SSNL - Laserfiche WebLink

Home Browse Search

5.3 Description of all current on-site sources of nitrate to soil and groundwater and the contribution of nitrate load from these sources to the project site: The sources of nitrate is the existing septic system in use by an existing parcel for residential uses. The existing septic system was accounted for when determining the approximate nitrate concentration, the site is expected to maintain its current flow with the proposed development. 5.4 Discussion of all proposed future on-site sources of nitrate to soil and groundwater and the contribution of nitrate load from these sources to the project site: The future use of the site will remain consistent. The existing residence with 1 bedroom was used to approximate the amount of people that could generate waste water flow. It was conservatively assumed that 100 gal/day would be generated for the first bedroom and 50 gal/day subsequently for every other bedroom, generating at a total of 100 gallons/day. The site is expected to be able to handle up to 6350 gallons/day, making the current flows sustainable. Similarly, there is no residences or definitive source of nitrates on the second 60 acre parcel; but 250 gal/day were used in assuming a residence could be built in the future. The 60 acre parcel would have no problem with these small flows, considering peak flow rate allowed is 6350 gal/day, but no major additions should be made without update to this report. The average total nitrogen concentration of domestic wastewater is about 20-85mg/L-N, although 35-45mg/L-N is a better approximation (Crites and Tchnobanglous). The value selected for this site was 45mg/L-N assuming this site shall experience a larger concentration. The site will experience a process of denitrification as the soil naturally treats surface material through natural forms. Denitrification is a process that occurs when bacteria uses oxygen in the nitrate (NO3) and release nitrogen (N2) into the atmosphere. Denitrification can be variable to the type of soils, chemical properties, moisture content and other variables. Based on the sandy loams on site and the high percolation rates, this site's soil has moderate levels of denitrification. It is expected that a site with soil of these characteristics shall have approximately about 10-15% of denitrification. The value used for this site was 15%. 5.5 Calculate mass balance of nitrogen loading considering all potential sources identified using Hanzteh/Finnemore equation: Using the data mentioned within this report and the attached Soil Suitability Study, the mass balance of nitrogen loading for this site was calculated. This was done using Hanztch/Finnemore formula. Based on the Hanztch/Finnemore equation, the two 60 acre sites would contain a Nitrate Load (Nc) of 9.97 mg/L-N when the site is generating its peak flows. (6350 gallons/day) 6.0 Discussion of nitrate loading results relative to proposed method of wastewater disposal 6.1 Discussion of total nitrate impact from proposed project: There are very low possibilities that the percolating effluent could affect ground water conditions.