Laserfiche WebLink
Recommendations of the On -Site Wastewater Treatment Systems <br />Nitrogen Reduction Technology Expert Review Panel February 2014 <br />Best Management Practice <br />Qualifying Conditions <br />In Situ <br />Reduction <br />Credit' <br />Elevated Mound <br />A or A/B) <br />4.0 kg/p/yr (0%) <br />2.5 kg/p/yr (38%) <br />• Scarify surface of soil under mound <br />NSF 40 Class I Secondary Systems <br />3.2 kg/p/yr (20%) <br />• Uniform, pressurized distribution <_ 6 sf/orifice <br />2.0 kg/p/yr (50%) <br />Intermittent Media Filter <br />• Minimum 0.5' (for secondary treated effluent) or 2' <br />2.0 kg/p/yr (50%) <br />2.0 kg/p/yr (50%) <br />(for STE) layer of sand: ASTM C33; <_ 20% by <br />3.2 kg/p/yr (20%) <br />2.0 kg/p/yr (50%) <br />weight > 2 mm; D10 = 0.15 to 0.3 mm; UC = 4 to 6 <br />Anne Arundel Co. IFAS <br />2.0 kg/p/yr (50%) <br />• Max. top of sand ALR = 1 gpd/sf for STE, 2 gpd/sf <br />1.25 kg/p/yr (69%) <br />Recirculating Media Filter <br />for secondary <br />1.25 kg/p/yr (69%) <br />1.25 kg/p/yr (69%) <br />• 6-12" loamy cover layer <br />• Credit not provided where sand or loamy sand <br />soils predominate within 12" below mound <br />Permeable reactive barriers <br />• Site-specific <br />Case-by- <br />case <br />TN reduction applied to ex situ system effluent load (from Table ES -1. <br />LPD = low pressure distribution; UC= uniformity coefficient; ALR = aerial loading rate; STE = septic tank effluent; D10 <br />= 10% cumulative undersize particle size distribution; gpd = gallons per day. <br />Table ES -3. Summary of Net TN Load Reductions for Combined In Situ and Ex Situ Systems. <br />In Situ Practice <br />Ex Situ Practice <br />Conventional <br />Baseline <br />Shallow, Pressure <br />Dosed <br />Elevated Mound <br />Septic Tank Baseline <br />4.0 kg/p/yr (0%) <br />2.5 kg/p/yr (38%) <br />2.5 kg/p/yr (38%) <br />NSF 40 Class I Secondary Systems <br />3.2 kg/p/yr (20%) <br />2.0 kg/p/yr (50%) <br />2.0 kg/p/yr (50%) <br />Intermittent Media Filter <br />3.2 kg/p/yr (20%) <br />2.0 kg/p/yr (50%) <br />2.0 kg/p/yr (50%) <br />Vegetated Submerged Bed <br />3.2 kg/p/yr (20%) <br />2.0 kg/p/yr (50%) <br />2.0 kg/p/yr (50%) <br />Anne Arundel Co. IFAS <br />2.0 kg/p/yr (50%) <br />1.25 kg/p/yr (69%) <br />1.25 kg/p/yr (69%) <br />Recirculating Media Filter <br />2.0 kg/p/yr (50%) <br />1.25 kg/p/yr (69%) <br />1.25 kg/p/yr (69%) <br />Note: Percent reductions in table entries represent net reduction from baseline of 4 kg/person/year at edge-of- <br />drainfield. <br />OTETRATECH,INC, <br />13 <br />