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r5�7�111.�NITRATE LOADING STUDY FINDINGS 2222�)) A. WASTEWATER FLOW VOLUME PROJECTIONS AND CHARACTERISTICS Wastewater Flow Volume Projections Typically, loading projections for commercial facilities are based on the maximum anticipated wastew to b�ulzied_peoflle-tha�cu €k4y-,-ment-h for singular events. The maximum number of people_potentially - ite for this facility will be 20. herefore,the commercia septic system description is as follows: The type o es airs-hmenuis`Irn ustrial building no oc c etena. 'The gallons per person per day is 15 gals. 20 people x 15 g/person/day= 300 gpd AD gp x 5 d/wk x 52 wks/yr= 78,000 g/yr. This figure will be used in the nitrate loading calculations below. Wastewater Characteristics The domestic wastewater generated from the facility will be composed of blackwater from toilets/urinals and greywater from hand washing and a break room sic. There should§ hi� organic loading from kitchen use, etc. Additional wastewater constituents may consist of other liquids to the system, such as coffee,juices, low strength cleaning liquids, etc. No industrial or commercial chemicals, solvents, etc. should ever be introduced into the wastewater treatmen system. It is imperative that low strength an 'rw volumes of cleaners are use m the i��ir�nr3 since they can disrupt the septic tank biology. The scientific literature cites nitrogen concentrations in do Mepic ging from 17 mg N/L for basins, sinks, etc. to 140 mg N/L for toilet wast s A /L s typically used for domestic calculations,as indicated in the literature( e a an ook,Pg. 147), based upon a mixture of the concentrations referenced above. B. CALCULATED NITRATE-NITROGEN LOADING NLS§3.4,3.5,3.6. The calculated nitrate-nitrogen impact to the soil and potentially 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 referenced upgradient nitrate sources,2.) Variability in wastewater flows, effluent nitrogen concentrations and dilution effects from Creek water/stormwater recharge, 3.) Changes in groundwater directional flow and elevation, 4.)And of significant importance is not only the denitrification potential of the indigenous tight loam soils, but . equally important is the diminished nitrification potential within this soil environment at the soil effluent interface. The small pore space within this soil significantly reduces oxygen content, thus impeding nitrification. The Hantzsche/Finnemore Formula is used below to predict the average concentration of nitrate- nitrogen in effluent recharge water from the proper anageent system. The calculations are based on g b is os m of 3.36 acres rrelated with the annually projected wastewater flo s of 19 68 rs primarily estimate a avera concentration of nitrate-m en recharge effluent which cannot exceed 0 ppm nitrate- nitrogen(45 ppm as nitrate). n' Page -6- Chesney Consulting