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4 rrTLEACHFIELD AND SEEPAGE PITS will be two restrooms available to employees, which could theoretically reduce the total ADF to each restroom by half. However, the total ADF will be used in the following calculations. Seepage pits will provide the potential need for temporary effluent storage and provide additional infiltrative surface, versus installing leachlines exclusively. LEACHFIELD EXAMPLE FOR NEW SEPTIC SYSTEM: 2,000 gallon septic tank. Therefore, the Base Tank Capacity = 2,000 gal: _ ✓ Base Tank Capacity (BTC) +Avera e Daily Flow(ADF) x Soil Factor (SF) = 2,000 gal BTC+(509 gal/day) 2,509 ADF x 0.250 SF= 627 lineal ft of leachline Y ffd In accordance with San Joaquin County Sewage Standards, at the end of three of the four 3(o leachlines may be a 36-inch diameter, 25 ft deep seepage pit. Each pit has an equivalent leachline ` length of 70 ft: 4(100 ft leachline) =400 ft+ 3 - 36'125' deep seepage pits = 3(70 ft) =210 ft= 400 ft+ 210 ft= 610 ft of leachline. E A 23 ft deep (accounting for invert inlet), 36 inch diameter seepage pit has an infiltrative surface area of 217 sq ft (excludes bottom area)'x 3 seepage pits = 651 total sq ft. The ultimate performance of the proposed seepage pits are affected by several variables such as: surface head, and the elevation, lateral extent, continuity and angle of the encountered porous strata. Surface head pressure will have significant influence on the infiltration of effluent into the soil below the referenced sand stratum. Consequently, the percolation rate obtained can be assumed to be an "average" percolation rate for 75% (17.3 ft) of the height of the deep perc test boring. As f illustrated on the Percolation Field Testing Report, a formula for determining a seepage pit application rate in gallons/sq ft/day suggests the surface area of the seepage pits should accept 2.5 gals/sq ft/day, based upon the percolation test results. NITRATE-NITROGEN IMPACT MITIGATION From the experiment of running two separate shallow (42 inch depth)percolation tests, it was determined that there is percolation at the shallow depth when the clay soils are not compacted. Therefore, full 100 ft length leachlines should be installed to take advantage of the alkaline clay surface soils and promote the denitrification process. Llnad&tion, by installing a filter(e.g.,Zabel® or OSI® Filters) in the second compartment of the tank will greatly reduce particulate matter from being deposited in the leachline trenches andutes to excessive biomat buildup. 10 Nadey Ag Research