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LUCCA WINERY SOIL SUITABILITY & NITRATE LOADING STUDY MAY 2013 logical, reasonable, contemporary, and applicable. Archaic Standards of 150 Average Daily Flow (ADF) per toilet are based on old-style toilets with a five gallon flush. New toilets use 1.5 gallons per flush. Although numbers of on-site people have not been estimated in the Application, the ADF for sizing criteria must be based on the premise of using a low-flow toilet at 1.5 gallons/flush. Anticipated flow volumes are as follows: A total of 24 flushes/dav will be assigned per toilet (24 flushes/toilet/day = 3 flushes/hr/8 hr day) for a total of 72 flushes/day x 1.5 gals/flush = 108 gals + 0.25 gallons for hand washing x 72 bathroom trips = 126 gallons ADF from the new restroom in Phase I and estimated restroom in Phase Il. ii. Wastewater Flow Characteristics It is assumed there will be no cooking, or food production in the restrooms. Therefore, there should be no 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 from a household. The scientific literature cites nitrogen concentrations in residential septic effluent typically ranging from 17 mg N/L for basins, sinks, etc. to 140 mg N/L 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, as indicated in -. the scientific literature. B. Calculated Nitrate-Nitrogen Loading 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, 2.) Variability in wastewater flows, nitrogen concentrations and dilution effects from effluent and stormwater recharge, 3.) Changes in groundwater directional flow and elevation, 4.) Denitrification potential within the soil environment and within the confined and unconfined aquifers and 5.) Potential landscape uptake of nitrogen. Various scientific methods exist to estimate nitrate-nitrogen loading. This Study will use the Hantzsche/Finnemore Formula to predict the average resultant concentration of nitrate-nitrogen in effluent recharge water. As calculated below, the property has been Page 19