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F7havean c eve opmen , almost a o e percentage o e ans ace wl a covere wl asphaltic concrete (AC) grinds over four inches of aggregate base (AB). This will nuating effect on the downward migration of nitrate molecules currently "in-transit"te yet to be formed within the area of the project. This semi-impermeable surface will beotential point sources of nitrate: the on-site septic system and landscaping. Domesticcharge can account for 250 to 1,500 gallons of water/day during the spring and summer months (approx. 6 mos. out of the yr). Excessive landscape watering can lead to nitrogen leaching, and runoff to open areas. Therefore, it is imperative that landscaping fertilization be kept to an absolute minimum,if at all. C. WASTEWATER FLOW CALCULATIONS AND CHARACTERISTICS A. WASTEWATER FLOW PROJECTIONS AND CHARACTERISTICS In accordance with requirements of the Environmental Health Department,this Nitrate Loading Study is to quantify the number of people (employees and customers)that will contribute to the nitrate loading of the subject parcel. Therefore, wastewater flows must be determined as accurately as possible. For typical facilities such as this one, EHD prefers loading projections be based on the total number of parking stalls for employees and customers who may potentially use the toilet/sink, etc. on a workday basis. The following chart illustrates the anticipated number of employees and customers to be associated with the property: NUMBER OF TOTAL NUMBER OF NUMBER OF DAYS OF PER CAPITA TOTAL. EMPLOYEES PARKING STALLS: CUSTOMERS/ OPERATION TOTAL, WASTEWATER THREE STANDARD, visrrORS FLOW ONE HANDICAP One Four Three per day Office Open Four per day 4 x 30 gpd= M-F, 8-5 120 gpd There will be no cooking within the office area of the future building, and consequently no need for a garbage disposal. Therefore, there should be no highly concentrated organic loading. The characteristics of the wastewater flow will be predominately blackwater from toilets, with a comparatively small volume of graywater from sinks, or other sources of graywater. Additional wastewater constituents may consist of coffee,juices or other similar type liquids to the system. No industrial or commercial chemicals, solvents, etc. are to be introduced into the septic system. From the anticipated wastewater characteristics described above, the nitrogen emanating from the project may be at a higher concentration than what would normally be found in a typical domestic or household system. This can be attributed to the lack of a dilution effect that graywater from showers, laundry, and dishwashing would provide. The scientific literature cites nitrogen concentrations in residential septic effluent typically ranging from 17 mg N/L for basins, sinks, etc. to 140 mg NIL for toilet wastes. Therefore, considering a 70/30 percent usage for toilet water volume and sink water volume, respectively, a value of 103 mg N/L of septic effluent will be used to calculate nitrate-nitrogen loading for this project. A value of 66 mg N/L is typically used for residential calculations. Page-5- Chesney age-5- Chestsey Consulting