Agenda - Council - 10/14/1997 - Laserfiche WebLink

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I I I I I I I I I I I I I i I I I § 8.30 Filter material for a soil treatment unit using gravity distribution of effluent shaIl not be placed in contact with original soils having a percolation rate faster than 0.1 m~nute per inch. For coarse softs having a percolation rate faster than 0.1 minute per inch, at least 12 inches of lo2my sand textured soft having a percolation rate between 6 and 15 m~nutes per inch at the original site shell be placed between the filter material and the coarse soft along the excavation bottom and sidewalls. The size of the soft treatment system must be based on the required treatment area for a soft having a percolation rate of 16 to 30 rn~nutes per inch as specified in Table II. For softs with percolation rates between 0.1 and 5 minutes per inch, at least one of the foZlowing treatment techrHques shall be used: a) Distribute the sewage tank effluent by pressure flow over the treatment area as specided in this chapter. b) D~vide the total soil treatment area into at least four equal parts connected serialIy;,.or c) Provide at least 12 inches of loamy sand textured soil with a percolation rate between 6 and 15 m~uutes per inch in situ between the drainfield rock and the coarse - soils. Trenches must be used with this liner system. The size of the soft treatment system must be based on the required treatment area for a soil having a percolation rate bet~veen 16 to 30 m~uutes per inch as specified in Table II. Mou~ds may be constructed on soils having the site or soil conditions spe~fied ~a §8.30'.04 Subd. 7. The soft percolation rate in all layers of the natural or fill soil to a depth of at least 24 inches below the sand shall be faster than 120 minutes per inch. The allowable absorption area loading rate must be detm-,,,~ued according to Table III by the percolation rate of the 12 inches of original or fill soft immediately under the sand layer. l°~nted 1~28/90 Page 255