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NITRATE LOADING STUDY FINDINGS WASTEWATER FLOW VOLUME PROJECTIONS AND CHARACTERISTICS Wastewater Flow Volume Projections To determine nitrate-nitrogen loading from any project, wastewater flow volumes must be determined as accurately as possible. Flow volume projections will be approximated from the potential number of on-site truck drivers/employees/customers, as illustrated in Table 3. It is my understanding that the proposed restroom this will be the only domestic wastewater fixture units for this project. According to EHD standards, people who are associated with a facility, whether they are employees are not, must have access to available restroom facilities. The following chart illustrates the Employees/Customers/Deliveries, etc. per work shift used to calculate the anticipated wastewater flow volumes. TABLE 3 Number of Employees Customers per Shift we/w Vehicles per Shift 4 8 31 Taking a reasonable usage factor of five gallons per day (2.5 gals AM, 2.5 gals PM) for each class of on-site people, including drivers even though they are long-haul and will not be on-site daily, we find the following: Total usage= 43 on-site people x 5 gpd/person = 215 gpd x 6 days per week = 1,290 gpw x 50 wks/yr = 64,500 gpy. Wastewater Characteristics Blackwater will originate from toilets and graywater from hand washing. Additional wastewater constituents may consist of other liquids to the system, such as coffee, juices, etc. Industrial or commercial chemicals, solvents, etc. must not be introduced into the wastewater treatment system. The scientific literature cites nitrogen concentrations in domestic septic effluent typically ranging from 17 mg N/L for graywater basins, sinks, etc. to 140 mg N/L for blackwater toilet wastes. Therefore, considering a 38/52 percent usage for toilet and hand wash water volume, respectively, a value of 62 mg N/L (38% of 140 mg N/L plus 52% of 17 mg N/L) from the septic effluent will be used to calculate nitrate-nitrogen loading for this project (See Kaplan - Septic Systems Handbook, Pg. 147). CALCULATED NITRATE-NITROGEN LOADING NLS§ 3.4, 3.5, 3.6. The 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, 5 Chesney Consulting