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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />3. For soils with percolation rates between one-tenth (0.1) and five (5) minutes per <br />inch, at least one of the following treatment techniques shall be used: <br /> <br />a. Distribute the sewage tank effluent by pressure flow over the treatment area <br />as specified in this chapter. <br /> <br />b. Divide the total soil treatment area into at least four equal parts connected <br />serially; or <br /> <br />c. Provide at least 12 inches of loamy sand textured soil with a percolation rate <br />between six and 15 minutes per inch in situ between the drainfield rock and <br />the coarse soils. Trenches must be used with this liner system. The size of <br />the soil treatment system must be based on the required treatment area for a <br />soil having a percolation rate between 16 to 30 minutes per inch as specified <br />in Table ll. <br /> <br />SUBDIVISION 4. MOUNDS. <br /> <br />1. Mounds may be constructed on soils having the site or soil conditions specified in <br />Section 150.0140. <br /> <br />2. The soil percolation rate in all layers of the natural or fill soil to a depth of at least <br />twenty-four (24) inches below the sand shall be faster than one hundred twenty <br />(120) minutes per inch. <br /> <br />3. The allowable absorption area loading rate must be determinedaccording to Table ill <br />by the percolation rate of the 12 inches of original or fill soil immediately under the <br />sand layer. <br /> <br />TABLE III <br /> <br /> Allowable absorption area loading rate I <br />Percolation rate of original soil gallons/day per square feet per <br />under sand layer, minutes square foot gallons per day <br />6 to 15 0.79 1.27 <br />16 to 30 0.60 1.67 <br />31 to 45 0.50 2.00 <br />46 to 60 0.45 2.20 <br />61 to 120 0.24 4.20 <br /> <br />4. Below the sand layer, there shall be at least one (1) layer of soil, either natural or <br />fill, at least twelve (12) inches thick, which has a percolation rate slower than five <br />(5) minutes per inch (loamy sand). <br /> <br />5. Wherever possible, mounds shall be located on flat areas or crest of slopes. <br />Mounds shall not be located on natural slopes of more than three per cent (3%) if <br />the percolation rate is slower than sixty (60) minutes per inch to a depth of at least <br />twenty-four (24) inches below the sand layer. <br /> <br />55 <br />