NR 811.45NR 811.45 Aeration. Aeration treatment devices described in this section may be used for oxidation, separation of gases, or for taste and odor control. Air stripping towers shall meet the requirements of s. NR 811.53 (2), which can be used for the removal or reduction of some volatile organic compounds. The following requirements shall be met: NR 811.45(1)(1) Natural draft aeration. The design for natural draft aeration shall provide that: NR 811.45(1)(b)(b) Water is discharged through a series of 3 or more trays with separation of trays not less than 6 inches. NR 811.45(1)(c)(c) Trays are loaded at a rate of one to 5 gallons per minute for each square foot of total tray area. NR 811.45(1)(d)(d) Trays have slotted, heavy woven wire mesh with 0.5-inch openings or perforated bottoms. NR 811.45(1)(e)(e) Perforations are 3/16 to 1/2 inches in diameter, spaced one to 3 inches on center, when perforations are used. NR 811.45(1)(f)(f) Construction is of durable material resistant to the aggressiveness of the water and dissolved gasses. NR 811.45(1)(g)(g) Contamination from sources such as those listed is sub. (7) is minimized by providing down-turned, louvered or hooded, screened air inlet or outlet openings. Screens shall be constructed of 24-mesh corrosion resistant material. NR 811.45(1)(h)(h) Exhaust air is discharged directly to the outside atmosphere and in a location that will be protective of public health. NR 811.45(2)(2) Forced or induced draft aeration. The design for forced or induced draft aeration shall provide that: NR 811.45(2)(b)(b) The blower and blower motor are weatherproof and are installed in a weather-tight, screened enclosure. NR 811.45(2)(c)(c) There is an adequate countercurrent flow of air through the enclosed aeration column. NR 811.45(2)(d)(d) Aerator trays are loaded at a rate of one to 5 gallons per minute for each square foot of total tray area. NR 811.45(2)(e)(e) Water will discharge through a series of 5 or more trays with separation of trays not less than 6 inches or as approved by the department. NR 811.45(2)(f)(f) Construction is of durable material resistant to the aggressiveness of the water and dissolved gasses. NR 811.45(2)(g)(g) The aerator is insect-proof, watertight, and light-proof. NR 811.45(2)(h)(h) The air intake is located above grade and the air introduced into the column is as free as possible from contamination sources such as those listed in sub. (7). NR 811.45(2)(i)(i) The water outlet is adequately sealed to prevent unwanted loss of air. NR 811.45(2)(j)(j) Interior and exterior sections of the aerator can be easily reached or removed for maintenance. NR 811.45(2)(k)(k) The air inlet to the blower and the tower discharge vent shall meet all of the following requirements: NR 811.45(2)(k)2.2. Be provided with a downturned, hooded, or mushroom cap that protects the screen from the entrance of extraneous matter including insects and birds, obnoxious fumes, all types of precipitation and condensation, and windborne debris or dust. NR 811.45(2)(k)3.3. Be constructed of 24-mesh corrosion resistant material and installed at a location least susceptible to vandalism or damage. NR 811.45(2)(L)(L) Exhaust air is discharged directly to the outside atmosphere and in a location that will be protective of public health. NR 811.45(3)(3) Pressure aeration. Pressure aeration installations shall meet the following requirements: NR 811.45(3)(a)(a) Pressure aeration may be used for oxidation purposes. Pressure aeration will not be approved for removal of dissolved gases.