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The EPA Onsite Wastewater Treatment System Manual indicates a weighted average daily flow (ADF) for residential structures of 68.6 gallon/person/day and residential populations are taken to be between 1 and 1.5 inhabitants per bedroom. The average number of inhabitants for the existing on- site structure is determined to be a total of three people (1.0 people x 3 bedrooms)theoretically each using 68.6 gallons per day. Therefore: 3 people x 68.6 gals/person/day=206 gals/day or 75,000 gallons/yr. The commercial coach is considered an office. According to EHD standards, day workers at offices are assigned 30 gallons per person per day,which is exorbitant and based on antiquated plumbing fixtures. Four office workers will occupy the coach, five days per week, 50 weeks per year: 4 people x 30 gals/day x 5 days/wk x 50 wks/yr= 30,000 gallons per year. Wastewater Characteristics Blackwater will originate from toilets and graywater from showers,hand washing, clothes washing and kitchen dishwashing. Additional wastewater constituents may consist of other liquids to the system, such as coffee,juices, etc. No industrial or commercial chemicals, solvents, etc. should be introduced into the wastewater treatment system. From the characteristics described above,the nitrogen emanating from the residence should be what is found in a similar or typical domestic or household system. The scientific literature cites nitrogen concentrations in domestic septic effluent typically ranging from 17 mg N/L for basins, sinks, etc. to 140 mg NIL for toilet wastes and a small volume of food wastes that may be introduced into the system through dishwashing. Therefore, considering a 38/52 percent usage for toilet and dish/hand/clothes/shower wash water volume,respectively, a value of 62 mg NIL (38% of 140 mg N/L plus 52%of 17 mg N/L) of septic effluent will be used to calculate nitrate-nitrogen loading for this project(See Kaplan-Septic Systems Handbook,Pg. 147). This same nitrogen concentration(62 mg N/L) will also be used for the proposed commercial coach. B. CALCULATED NITRATE-NITROGEN LOADING �S§3.4,3.5,3.6.-T�e calculated nitrate-nitrogen impact to the soil and ultimately to the groundwater is difficult to determine due to the large number of variables involved and variables unknown at this time. These include: 1.) Impact from upgradient nitrate sources, 2.)Variability in wastewater flows, nitrogen concentrations and dilution effects from upgradient and surrounding bodies of water and stormwater recharge, 3.) Changes in groundwater directional flow and elevation, 4.) Denitrification potential within the soil environment and within the confined and/or unconfined aquifers and 5.) Efficiency of nitrate mitigating design factors, 6.)Potential landscape uptake of nitrogen. Various scientific methods exist to estimate nitrate-nitrogen loading. The Hantzsche/Finnemore Formula is used to predict the average resultant concentration of nitrate-nitrogen in effluent recharge water from the residential structure and the proposed commercial coach septic system. As calculated below,the property has been assessed on a total areal loading basis correlated with the total projected yearly wastewater flow volumes calculated above. These two factors primarily estimate the average resultant concentration of nitrate-nitrogen in the recharge water. This concentration cannot exceed 10 ppm nitrate-nitrogen(45 ppm as nitrate). 7