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Trans Sohal Logistics—Nitrate Loading Section Page 11 of 13 Our Project Number: LGS140011 October 8,2014 Table 4. Typical Quantity of Effluent. Category Total People Average Quantity per Average Daily Flow per Parcel per Day Person Permanent 3 *13 gal/day/employee (3 employees* 13 gpd) = 39 gpd Employees Occasional 3 *5 gal/day/visitor (Maximum 3 Visitors* 5 gpd) = 15 gpd Visitors Note: gpd is gallons per day. *Value cited from Crites, R. &Tchobanoglous, G., Small and Decentralized Wastewater Management Systems, 1998. Table 4-2: Typical Wastewater Flowrates from Commercial Sources. For the subject property, the total daily wastewater quantity for office employees is 39 gallons per day and for maximum occasional visitors is 15 gallons per day, for a total of 54 gallons per day. A five-sevenths conversion was used for the permanent on-site employees and visitors to account for a five day work week. Five-sevenths of 54 gallons per day is 38.57 gallons per day average. The average total nitrogen concentration of domestic wastewater is normally considered to be J �� 20-85 mg/L-N with 35 to 45 mg/L-N being typical (Crites and Tchobanoglous, 1998). It is ... estimated that commercial use will have higher concentrations of total nitrogen when compared to residential use. It is estimated that_t#e age concentration for total nitrogen in wastewater for the project is approximat y85 mg/L- over the long term. _ 2.3.4.2 Denitrification Estimate Denitrification is an important process which occurs within the leach field whereby certain bacteria utilize the oxygen in the nitrate (NO3) and release nitrogen gas (N2) to the atmosphere. Denitrification is expressed as a percentage, and the normally accepted range is 10 percent to 35 percent. Soils with higher clay content, moist soil conditions, high pH, and organic material denitrify by about 35 percent, and soils with high sand content and fast percolation rates are estimated to denitrify at a lower rate, about 10 percent to 15 percent. A denitrification factor � 15 percent,'was selected for the Site because of the silty sand soil at depth (>18 feet bgs) with-a.fast percolation rate. 2.3.5 Nitrate Loading Scenario A nitrate loading scenario was performed to determine the impact from the proposed project. The scenario utilizes the variables discussed previously which represent the estimated conditions and uses associated with this project. The following table presents a summary of the nitrate loading calculation for the site, as presented in Plate 8. ©2014 Neil O.Anderson&Associates,Inc. A Terracon Company