SECTION 252:641-12-4. Low pressure dosing fields

(a)   Location. All low pressure dosing fields shall be:

(1)   located in the identified dispersal site;

(2)   installed more than five feet (5') from the septic tank or aerobic treatment unit; and

(3)   preceded by a low pressure dosing tank.

(b)   Header line. The header pipe (i.e., the pipe between the pump tank and the manifold) shall:

(1)   have a diameter the same as the diameter of the outlet of the low pressure dosing pump; and

(2)   be no longer than thirty feet (30').

(c)   Total linear length. All low pressure dosing fields shall meet the total linear length requirements set forth in Appendix H, Figures 8 and 9.

(d)   Trench length. Each trench in a low pressure dosing field shall be forty feet (40') long.

(e)   Trench spacing. The trenches in a low pressure dosing field shall be spaced six feet (6') apart, center to center.

(f)   Trench width. All trenches in a low pressure dosing field shall be twenty-four inches (24") wide.

(g)   Trench depth. Each trench in a low pressure dosing field shall have a uniform depth of at least fourteen inches (14") and no more than thirty inches (30"). The bottom of the trenches shall be level.

(h)   Dispersal and storage. Each trench in a low pressure dosing field shall contain a zone for the dispersal and storage of effluent comprised of low pressuring dosing pipe and storage media.

(1)   Low pressure dosing pipe. Low pressure dosing pipe shall:

(A)   meet the minimum specifications listed in Appendix C;

(B)   have one-fourth inch (1/4") diameter holes spaced five feet (5') apart the entire length of the pipe;

(C)   extend the entire length of the trenches; and

(D)   have all of the joints glued.

(2)   Storage media. The storage media shall:

(A)   be at least six inches (6") deep and at least twenty-four inches (24") wide the entire length of the trench;

(B)   be installed with at least two inches (2") of the storage media above and two inches (2") of storage media below the low pressure dosing pipe; and

(C)   be level:

(i)   in each trench; and

(ii)   across the low pressure dosing field.

(i)   Retention structures prohibited. Retention structures may not be used in low pressure dosing fields.

(j)   Backfill. For low pressure dosing fields:

(1)   the depth of the backfill shall be consistent and shall not vary more than four inches (4"); and

(2)   the backfill shall consist of at least eight inches (8") of topsoil.

(k)   Layout examples. There are layout examples located in Appendix K, Figure 3, and Appendix M, Figure 3.

[Source: Added at 25 Ok Reg 2318, eff 7-11-08]