1978-06-07 Septic System Design - Laserfiche WebLink

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II. DISTRIBUTION OF EFFLUENT 1. BY GRAVITY FLOW OVER THE SOIL TREATMENT AREA A. Level Ground Wi%rre the elevation difference of the ground surface does not exceed P inches in any dire(�.Ion within the soil treatment area, the sewage tank of uent may be directed to the soil treatment area through a distribution box. See Detail). Oistriuution boxes may not be allowed by certain governing bodies or municipalities. Contractor shall contact appropriate authorities for such determination. 1. The box shall be watertight with a removabl- cover- and shall be constructed of durable materials not subject to excessive= rorr-osion or decay. The minimum insi-ie� dimension be at: least ton int:ht- 2. The inverts of all outlet Shall be at the - n.- -1evttion as measured from a Iiqui,' surtacN in the bottom of the box. 1 3. Thz inlet invert shall be at least one inch above tht• outlet inverts. 4. The cutlet inverts shall be at least four rr.ches above thr distribution box f Ioor-. b. Each drainfield trench- line shall be connected separately to the distribution box and ;hall no' be subdivided. .then sewage tank'effluent rs delivered to the distribution box by pump, either a baff t wall shall be, in;'.alled in the distribution box or the pump discharge s 11 be directed against a wall or- side of the box on which there is no out t. The baffle shall be secured to the borc,and shall extend at least inch above the crown of the inlet flow line �\ B. Sloping Ground (AS r 1>0"P 9 OXcs Where the elevatrnn difference of the ground surface exceeds 28 inches in any direction within soil trcitment arta a drop box shall be installed at the head end of each literal line. Connections between drop boxes shall be by watertight pipes. (See Detail). 1. The drop box shall be watertight and constructed of durable materials not subject to excessive corrosion or decay. The minimum inside dimension shall be at lea3t ten inches, unless the box is to be used as a valve box. Then each outlet shall have at least eight inches of sidewall space and the side of any outlet shall be at least six inches from any corner. 2. The invert of the inlet pipe shall be at least one inch higher than the invert of the outlet pipe to the next trench. 3. The invert of the outlet pipe to the next trench shall be at least two inches higher than the invert of the outlet pipe of the trench in which the box is located.