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�T December 12,2006 NOA Project Number: E06094A ` The following tables presents the septic waste water uses associated with the Site. The rates presented from the references provide general guidance but do not always reflect a match in usage. Careful examination,professional judgement, and experience are necessary to select a reasonable flow rate estimate. The flow rates selected for maximum uses associated with this project are presented in the following table. r Table 2. Typical Quantity of Effluent l~ Category Total People per Average Quantity per Average Daily Flow Day Person Per Parcel l Parcel 1,2,3& Designated 5 70 gal/day/resident 5 residents 70 gpd/resident = 350 gpd Remainder Parcel 4 4 70 gal/day/resident 4 residents* 70 gpd/resident = 280 gpd Note -gpd is gallons per day. For parcels one, two, three and the Designated Remainder, the total daily waste water quantity is 350 gallons per day. For parcel four, the total daily waste water quantity is 280 gallons per day. The average total nitrogen concentration of domestic waste water is normally considered to range f F°# from 20 to 85'mg/L-N with 35 to 45 mg/L-N being typical (Crites and Tchobanoglous, 1998). For thepurposes of the nitrate loading estimate, the long-term average concentration for total nitrogen in waste water'is estimated to be 45 mg/L-N. �k 3.4.2 Denitrification Estimate Fi 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 (N) to the atmosphere. Denitrificatioti 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 $ j 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. F! A typical denitrification factor of 35 percent was selected for the Site because of the peat that exists at the site. i r 6 }