When a surface sand filter is used as a component of an aerobic type treatment system it shall comply with the following requirements:
(A) The surface sand filter shall have a minimum filter area of thirty square feet.
(B) The effective size of the filter sand shall be six-tenths to one millimeter with a uniformity coefficient not to exceed three.
(C) The minimum depth of the filter sand shall be eighteen inches.
(D) A minimum of twelve inches of freeboard above the upper sand surface shall be provided.
(E) The effluent shall be distributed over the entire sand filter area.
(F) Dosing devices, if required, shall be provided with a pump having a minimum capacity of 3.75 gallons per minute.
(G) The sump for the dosing device shall have a minimum working volume of seventy-five gallons.
(H) The sand filter shall be covered with durable grating constructed of materials resistant to corrosion and decay, or surrounded by a fence to prohibit unwarranted or unauthorized entry.
(I) A sampling well with a minimum inside diameter of eight inches shall be installed on the surface sand filter discharge line within six feet of the filter bed, accessible from the surface of the ground, and provided with a secured cover.
Promulgated Under: 119.04
Statutory Authority: Sec. 120.02 of Am. Sub. HB 119 (127th G.A.)
Rule Amplifies: Sec. 120.02 of Am. Sub. HB 119 (127th G.A.)
Prior Effective Dates: 7/1/1974, 7/1/77, 7/2/07