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February 27,2002 <br /> Job Number: LG02-048 <br /> Page 1 I <br /> Nitrate from Septic System <br /> The quantity of effluent waste water was estimated to be 70 gallons per person per day <br /> based on a publication by Crites and Tchobanoglous.8 A typical 4-bedroom home was estimated <br /> to include as many as 5 persons. A 1500 sq-ft second dwelling unit can contain up to 3- <br /> bedrooms and exist on the site. We estimate that the second dwelling unit may contain up to 4 <br /> - additional persons on the parcel. The total daily flow for a four(4)bedroom home is about 350 <br /> gallons per day (See Table 6). The Second Dwelling Unit could potentially add an additional 280 <br /> gallons per day of waste water. Together, the four bedroom residence and second dwelling unit <br /> could be occupied by 9 people with a total estimated flow of 630 gallons per day(Table 6). The <br /> average total nitrogen concentration of the typical residential septic waste is considered to be 35 <br /> mg/L-N.' <br /> Table 6. <br /> Total Estimated Effluent. <br /> (see worksheets in Appendix for calculations) <br /> Category Quantity People Estimated quantity per category <br /> Residence(4-bedroom) 70 gpd/person 5 70 gpd/person x 5 people=350 gpd <br /> Second Dwelling Unit(3-bedroom) 70 gpd/person 4 70 gpd/person x 4 people=280 gpd <br /> Combined 70 gpd/person 9 70 gpd/person x 9 people=630 gpd <br /> (4-bdnn Res.and 3 bdrm SDU) <br /> Note:bdr n-bedroom,SDU-second dwelling unit,gpd-gallons per day. <br /> Nitrate from Agriculture <br /> Leaching losses of nitrate fertilizer occur when soils have more incoming water(rain or <br /> irrigation) than the soil can hold. As water moves through the soil, the nitrate(NOO that is in <br /> soil solution moves along with the water. Ammonium (NH,') forms of N have a positive charge <br /> and are held by the negative sites on the clay in the soil; therefore,NH4' forms of N leach very <br /> little. In sands where there is very little clay, ammonium forms of N can leach. Coarse-textured <br /> sands and some muck soils are the only soils where ammonium leaching may be significant. <br /> One way to minimize N leaching and denitrification is to minimize the time the N is in the soil <br /> 8 Crites,R,and Tchobanoglous,G., 1998,Small and decentralized wastewater management systems: <br /> McGraw-Hill Publishing Company, 1084 p. See Tables 4-1 (p.170)and 4-14(p. 181). <br /> PERS 1 <br /> W <br /> O � <br /> �'fS OG♦ <br />