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F tic Tank Volume Hydraulic Detention Time Example - Gas Station and venience Storention Time =7,000 gal septic tank capacity x 0.70 (30%volume lost to sludge/scum accumulation) 2 (Peaking Factor) x 2,250 gals/day Detention Time= 1.0 day. 7-wG0.NGhUSIONSTANDTREGOMMENDATIONS SSS§ 5.4 The.— opsit moils wi'tfiin the.proposed wastewate%disposal area are eonducivefor-the acceptance_and*managufferofseptictank treatcAeffluent7 Percolation test results indicate that sufficient soil porosity exists for acceptable permeability through the soil profile of the disposal area. Only at the 15 ft depths at the two test sites was percolation found to be exceedingly slow. Although this impermeability may be somewhat attributable to the in-place soil samples retrieved by hammering the split-spoon sampler at this depth, the two deep borings were "reamed-out"with the auger at this depth after the soil samples were retrieved. Consequently, it can be concluded that there is only a small probability that soil compaction occurred from the in-place sampling method that may have contributed to slow permeability. In addition,MoundingTAn'7a }ysis calculations show thatr4ver,.-a ten--ye" ear time-s--p o app"'lying-fhe cal'culffted,wastewatgr fly_ow�of 25,080 gpd(Tale 8xPagetl7)' predict I-9f:only�a�1�68�ft rise-in t Trp`ot nttahwafer talile bove;tlus:slowly pe-imeable-stiatTitriw illi occur�!t i { It is unknown has to how pervasive this slowly permeable stratum at 15 feet is throughout the proposed disposal area. hi two of the five backhoe test pits at the southern end of this area, the soils were a silty sand at the 15 It backhoe test pit depths. Therefore,it may be concluded that this stratum is not overly pervasive throughout the entire 3.89 acre area. SSS§ 6.8 Averaging the acceptance rates derived from the percolation rates, we find that relatively j beneficial rates are found at the two test sites. For example, taking the slowest acceptance rates derived from the southwest comer test site of 0.574 gallon/ft'/day, and applying the calculated ADF obtained from EHD Requirements of 29,400 gpd (Table 8, Page 17), we find a disposal area of: 29,400 gpd_ 0.574 gallon/ft2/day= 51,220 W or 1.17 acres of disposal area would be required for complete build-out of Phase 1,based on the test results. As referenced,Q!I acres arable- orm many tdisposal,_a d-3'sl acres.are_available forjY00%o.cep`lacemen1 t Infiltration rates obtained from the Double Ring Infiltrometer Test reveals that slow permeability exists at a shallow plow-pan stratum at approximately one foot depth below the soil surface. The slow permeability of this layer is easily overcome by"ripping"the proposed disposal area with two foot shanks or a three-foot slip plow. This would be especially important if drip irrigation of the effluent, and/or Infiltrator Chambers®were installed. Page -23- Chesney Consulting i