SECTION 252:626-13-3. Drying beds

  Drying beds shall be designed based on the amount of residuals produced and other site specific criteria including climatic conditions, quantity of residuals products, the method and frequency of solids removal, and land requirements. The design shall include the following:

(1)   a minimum total filter area, regardless of the volume of water to be handled, of 100 ft,

(2)   protection from flooding by surface runoff or floodwaters, in accordance with OAC 252:626-5-3,

(3)   drying beds to facilitate maintenance, mechanical cleaning, and removal of surface sand and residuals,

(4)   drying bed media consisting of a minimum of 12 inches of sand, 3 inches of supporting gravel or torpedo sand, and 9 inches of gravel in graded layers. Wash all sand and gravel to remove fines,

(5)   drying bed sand with an effective size of 0.8 to 1.2 mm and a uniformity coefficient not to exceed 1.7. Alternate bed material will be considered on a case-by-case basis,

(6)   an adequate under-drainage collection system to permit satisfactory discharge of the filtrate to the backwash lagoons, and

(7)   surface area designed so that during any one filtration cycle, no more than 2 feet of wastewater will accumulate over the sand surface.

[Source: Added at 18 Ok Reg 1612, eff 6-1-01; Amended at 25 Ok Reg 2304, eff 7-11-08; Amended at 29 Ok Reg 1035, eff 7-1-12]