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22�) The EHD Onsite Wastewater Treatment Systems Standards Design Requirements for this locale specify 110 ft lineal ft of leachline (LFLL) + 98 ft of seepage pit equivalent=208 LL Eq. Converting 208 LL Eq. to a filter bed requires multiplying this figure by a soil factor of 3 (loam soils at the soil-effluent interface) =208 x 3 = 624 ft2 of needed application area. Application area of 40' x 10' filter bed= (40' x 2' x 2) + (10' x 2' x 2) +40' x 10' (floor) = 600 ft2 Additionally, a 2' W x 10' L x 8' D (6.5' app. area) sump is to be installed at end of the filter bed. Application area of sump = (6.5' x 2' x 2) + (6.5' x 10' x 2) +2' x 10' (floor) = 176 ft2. The proposed total effluent application area= 600 ft'- (filter Bed) + 176 ft2 (sump) = 776 ft2 > 624 ft2. A 1.5 ft wide retaining partition is to remain during filter bed/sump excavation, as illustrated on the Design Plans. This partition is to be situated between the filter bed and the sump and will force effluent to remain in the filter bed. Using the average of the application rates from the 40" and 94" depths, as determined from the perc tests conducted= 0.757 gallons/ft2/day+ 0.614 gallons/ft2/day= 1.371 gals/ft2/day_ 2 = 0.686 gals/ft2/day. Max. Average Daily Flow(ADF) of 140 gals/bedroom x 2 =280 gpd 280 gpd ADF - 0.686 gallons/ft2/day=408 ft2 of needed acceptance area based on perc rates. Proposed filter bed+ sump = 776 ft2. The 100%reserve/replacement area is identical to the primary disposal area, with a 10 ft separation distance between the two filter beds/sumps, as illustrated on the Design Plans. OPERATIONS AND MAINTENANCE PLAN Under Section 1.12.1 of the EHD OWTS Standards Manual, "All engineered designed OWTS shall be operated and maintained pursuant to an Operations and Maintenance Plan (OMP) compiled by the designer." The following comprises the OMP: 1. The septic tank for the SFR should be inspected every three years and pumped-out if inspection warrants pumping. 2. The D-Box for the SFR structure should be inspected at three year intervals to ensure equal distribution of effluent among the two perforated laterals. 2. All food wastes, including fats, oils and grease must be handled as solid wastes and disposed of into the garbage. There should be no garbage disposal in the kitchen sink. 3. Flushable wipes and other types (baby, disinfecting, makeup) must not be flushed down the toilet. Introduction of these materials into the septic tank will cause premature system failure. Page -5- Chesney Engineering, Inc.