Distribution

Distribution. The inlet and outlet on the tank (septic tank or ATU) must be 4 inch Schedule 40 pipe for a minimum of 3 feet onto undisturbed soil. Once the outlet pipe has extended a minimum of 3 feet onto undisturbed soil, it can then be reduced to a minimum of 3 inch Schedule 40 pipe for the entire discharge line: 1. Gravity Fed: a. Single point discharge: Gravity-fed discharge using a single point discharge line on 1% or greater slope. b. Distribution manifold: For gravity-fed multi-point discharge distribution by manifold, the level manifold must be constructed using flow diverting devices [see Figure 24] in such a manner as to be self-draining. A distribution box may be used for multi-point discharge. The distribution box must be installed level to ensure equal distribution of effluent. Outlet lines should have equal slopes for a minimum of 5 feet after leaving the D-box. The D-box should have a baffle wall, or some means of reducing the pressure from the inlet flow. [See Figure 26.] 2. Pressurized Distribution: a. Distribution box: A distribution box may be used for multi-point discharge. The distribution box must be installed level to ensure equal distribution of effluent. Outlet lines should have equal slopes for a minimum of 5 feet after leaving the D- box. The D-box should have a baffle wall, or some means of reducing the pressure from the inlet flow. [See Figure 26.] b. Distribution manifold: If effluent is to be delivered to a level manifold under pressure, the distribution system shall be designed to provide pressure at the point of discharge not to exceed 5 pounds per square inch. This can be achieved by pumping directly into the head of the manifold or into a baffled distribution box. [See Figure 27.] Source: Miss. Code Ann. § 41-67-3. FIGURE 24 – Gravity Fed Manifold Source: Miss. Code Ann. § 41-67-3. FIGURE 25 – Terrace Plant Beds Source: Miss. Code Ann. § 41-67-3. FIGURE 26 – Distribution Box Source: Miss. Code Ann. § 41-67-3. FIGURE 27 – Pressurized Manifold