SR0081560_SSNL - Laserfiche WebLink

Home Browse Search

D. OPERATIONAL PARAMETERS AND COMPONENTS SSS§ 3.7. An overview of the system operation to serve the proposed residential structure is as follows: Influent will gravity flow into a P&L Concrete, Inc. standard precast, 1,200 gallon septic tank. The tank must be set perfectly level and as high in elevation as possible. A Polylok® PL-68 effluent filter is to be installed on the sanitary tees of both side outlets of this tank. Clarified effluent will gravity flow equally from both side outlets to 3" perforated pipe running down the center of both 7 ft wide, 37 ft long filter beds. Perforated pipe is to run level and with capped ends to force as equal effluent distribution as possible. A minimum of 12" of washed drain rock, preferably 18" of rock, is to be placed under the perforated pipe, and extending 2" above the perforated pipe. Geotechnical filter fabric is to be placed over the drain rock and backfilled to grade with native soil. CONCLUSIONS AND RECOMMENDATIONS NLS§ 4.2. The shallow subsurface soils underlying the subject property where the two new filter bed disposal areas are to be installed, reveal a sandy loam soil structure with comparatively rapid permeability and a medium-to-high degree of natural denitrification potential. This potential is based upon the observed significant decrease in nitrate-nitrogen concentration with decreasing soil depth. NLS§ 4.1. The nitrate loading calculations show the resultant effluent from the proposed primary residential structure will theoretically possess a concentration of approximately 9.9 ppm as nitrate- nitrogen, which is under the MCL for nitrate-nitrogen at 10 ppm. The application rate of the shallow soils (36" depth) was determined from the perc rate to be 0.743 gallons/ft2/day. The total filter bed area is 518 ft2 of floor area. Therefore, the filter bed can manage: 0.743 gallons/ft2 /day x 518 ft2 = 385 gpd. The ADF was calculated to be 280 gpd. There is no on-site domestic well on the property. The proposed project has received a Will-Serve Letter from the City of Stockton to provide city water to the residence. NLS§ 4.2. All Onsite Wastewater Treatment Systems (OWTS) will eventually fail. A reasonably long lifespan of the primary disposal field can be expected based on the perc rates obtained and the incorporated design factors. Page -7- Chesney Consulting