SU0012939 SSNL - Laserfiche WebLink

Home Browse Search

Mr:George Rose March 1,2002 ,Page 2 ; The quantity,of household waste water was estimated to be 50 gallons per person per day. In a residence of three(3)or(4)bedrooms, the typical occupancy would probably range between. two (2) to four(4) persons per day resulting in a daily waste water flow between 100,to 200 gallons,per day. The potential impact of a, legally permitted second dwelling unit containing three (3)bedrooms is estimated to include an additional three(3)people to the property. The second dwelling unit could potentially contribute and additional 150 gallons per day to the site. . See Table 2 for the total estimate daily effluent flow. Table 2. Total Daily Effluent. (see worksheets in Appendix for calculations) Category Quantity Maximum Daily effluent quantity for each analysis Occupancy Main 50 4 people 50 gallons/day/person x 4 people=200 gallons/day Residence gallons/day/person L 50 Additional gallons/day/person 3 people 50 gallonsidaylperson x 7 people=350 gallons/day Dwelling (4+3—'7) The average nitrate concentration of the typical residential septic waste is normally considered to be.45 mgIL-N.Z The deep percolation of rain for the site was estimated to be 6.79 inches (Plate 2). The concentration of nitrates in rain water is estimated to be 0-17 mglL-N, according to work presented by Hantzsche and Finnemore. A denitrification factor of 25%was utilized due to fine'grained soils encountered at the site. The nitrate loading analysis was performed for the smallest parcel size of 2.10 acres. This is the most conservative calculation since the impact is the less fof larger parcels. Table 3 presents a summary of the nitrate loading analysis which considers nitrate sources from septic systems and rainfall: 2 Otis,R.J.,Boyle,W.C., 1980,Design manual,onsite wastewater treatment and disposal systems:.U.S. . Environmental Protection Agency,EPA 62511-80-012. (Seepage 100,table 6=1). '�pE RrQy r