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The maximum number of people potentially on-site for this agricultural facility will be a maximum of five people per day, eight hours per day, six days per week. If the toilet and lavatory are used twice per hour, for a total volume of 2.0 gallons each use, we find: 2.0 gallons/use x 2 uses/hr x 8 hrs/day 32 gallons/day (ADF) x six days/wk x 52 wk /yr = 9,984 gals/yr. This figure will be used in the nitrate loading calculations below. A shower is proposed to be installed, but this will only be used in an emergency. Wastewater Characteristics The domestic wastewater generated from the Ag Building will be composed of blackwater from toilets and graywater from hand washing. There will be no high organic loading from a 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 agricultural chemicals, solvents, etc. should ever be introduced into the wastewater treatment system. It is imperative that low strength and low volumes of cleaners are used in the restroom since they can disrupt the septic tank biology. The scientific literature cites nitrogen concentrations in domestic septic effluent ranging from 17 mg N/L for basins, sinks, etc. to 140 mg N/L for toilet wastes. A value of 62 mg N/L is typically used for domestic calculations, as indicated in the literature (See Kaplan - Septic Systems Handbook, 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 upgradient nitrate sources, 2.) Variability in wastewater flows, effluent nitrogen concentrations and dilution effects from rainfall recharge, 3.) Changes in groundwater directional flow and elevation. The Hantzsche/Finnemore Formula is used below to predict the average concentration of nitrate- nitrogen in effluent recharge water from the proposed wastewater management system. The calculations are based on a total areal loading basis of 67.19 acres, correlated with the annually projected wastewater flows of 9,984 gpy. These two factors primarily estimate the average concentration of nitrate-nitrogen in the recharge effluent, which should not exceed 10 ppm nitrate- nitrogen (45 ppm as nitrate). CALCULATED NITRATE-NITROGEN LOADING FROM THE PROPOSED RESTROOM TAKING THE ENTIRE SUBJECT PARCEL AREA INTO CONSIDERATION: HANTZSCHE/FI1VNEMORE EQUATION INw 11 - d) + R Nb Nr = (I + R) Page -5- Chesney Consulting