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I <br /> 77­7 <br /> NLS§ 4.1. The nitrate loading potential ca ted on F ge or the Public/Em p oyee es ooms <br /> and Page 10 for the two residential stru es in 'cate the perc lating effluent w theoretical y <br /> 6SS§,4.1. <br /> resultant nitrate concentration o 40.4 pp an (9.6"ppm s nitrate, respectively, which is <br /> he drinking water Maximum Co tami t Le l (MCL} f 45 ppm as nitrate. <br /> The nitrate loading potential from both sources were quantified separatel�d cannot be <br />' combined or added together. It is important to recognize that when adding one concentration of a <br /> solute (i.e.,NO3-N concentration determined in the effluent recharge from the Deli/Kitchen) to <br /> another concentration of a solute (i.e.,NO3-N concen. n termined from the residential <br /> structures), where both solutes are in ppm, the resulvwnot c ulative or the sum of the two solutes. <br /> Parts per million is a mass ratio (mg perl06 mg). Fo�, ple, the Nr (the resultant average <br /> concentration of nitrate-nitrogen in effluent recharge in ppm of NO3-N from the two sources), was <br /> determined to by the Hantzsche-Finnemore Equation to be 9.1 milligrams of nitrate in 106 milligrams <br /> of water(one liter) for the Restrooms and 6.7 milligrams of nitrate-nitrogen from the residential <br /> structures. If this 9.1 ppm concentration is added to the same volume of water(I x 106 milligrams) <br /> a�'h <br /> concentrationdet d for the residential ruc es, then the resultant concentration is now: <br /> illigrams per liter+ 6.7 illigrams per liter15.8 m lligrams nitrate-nitrogen in 2 x .106 <br /> rams (2 liters, or p er 2 million) of wat <br /> I <br /> Therefore, to convert back to ppm, the numerator and Odinat must be divided by 2 withthe <br /> result of 7.9 milligrams NO3-N per 1 x 106 milligramsnitrate NO3.`The water table <br /> mixing layer nitrate-nitrogcn concentration is unkno higher than what was determined <br /> in the well water. Therefore, it is unknown whether ththeoretical dilution effect from <br /> the percolating effluent and create a nitrate concentration less than what is currently found in the <br /> water table underlying a future effluent disposal area. In addition, if the effluent nitrate <br /> concentration from both sources (35.1 ppm as nitrate)were to percolate down to the drinking water <br /> aquifers with a groundwater nitrate concentration of 18 ppm nitrate, t result concentration <br /> would be: 35.1 ppm + 18 ppm= 53 ppm-2 =26.6 ppm nitrate, whic is still be ow.the MCL of <br /> ppm nitrate. <br /> It is imperative that all food and food b - roduct wastes rom the delAitchen are handled as solid <br /> wastes and placed in the garbgge, and not be disposed o into the se tics stem. This will preven <br /> concentrated or anic loading, rolon the Lifes an o the wastewater dis osal system and reduce <br /> nitrate loading potential The kitchen sink must not contain a garbage disposal and oils and <br /> grease must not be poured down the sink drain. <br /> Total Suspended Solids (TSS) can create and enhance biomat formation between the soil and <br /> effluent interface, thus restricting infiltration. The biomat, also referred to as a"clogging mat,"is a <br /> biological, slimy substance which forms on the soil-effluent interface over time. This mat is <br /> composed mostly of aerobic and anaerobic bacteria and bacterial-products consisting of polyuronides <br /> and polysaccharides. The biomat does have the beneficial property of removing approximately 10% <br /> of the nitrogen from wastewater disposal systems, although this figure was not used above in the <br /> nitrate loading calculations,to maintain a conservative loading concentration. <br /> 12 <br /> Chesney Consulting <br />