NR 811.53(3)(a) (a) The maximum filtration rate for pressure filters shall be 6 gallons per minute per square foot of filter area. The maximum filtration rate for gravity filters shall be 3 gallons per minute per square foot of filter area. Higher rates may be justified based on pilot studies for removal of the contaminant in question.

NR 811.53(3)(b) (b) The water from the carbon filter shall be continuously disinfected.

NR 811.53(3)(c) (c) The filter design shall provide for:

NR 811.53(3)(c)1. 1. Loss of head gauges on the inlet and outlet pipes of each filter.

NR 811.53(3)(c)2. 2. A meter or flow indicator.

NR 811.53(3)(c)3. 3. Adequate freeboard for backwashing based on the specific gravity of the media.

NR 811.53(3)(c)4. 4. An underdrain system to effectively collect the filtered water and distribute the backwash water.

NR 811.53(3)(c)5. 5. Backwash and air relief valves having discharges that terminate in a free air break at least 24 inches above the floor.

NR 811.53(3)(c)6. 6. Smooth-end sampling faucets on the inlet and outlet pipes of each filter.

NR 811.53(3)(c)7. 7. The ability to conveniently inspect, replace, or regenerate the media.

NR 811.53(3)(d) (d) The carbon used shall be virgin carbon.

NR 811.53(3)(e) (e) Information supporting selection of the carbon for removal of the contaminants in question shall be provided to the department.

NR 811.53(3)(f) (f) A plan for the disposal of the spent carbon shall be included in the specifications. Disposal of spent granular activated carbon shall comply with s. NR 811.859.

NR 811.53(3)(g) (g) An assessment of the impacts of radon and its decay products on operation, operator safety, and waste disposal shall be provided to the department.

NR 811.53 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: am. (2) (e) 7. Register January 2024 No. 817, eff. 2-1-24.

NR 811.54 NR 811.54 Ozonation. Ozonation can be used for a variety of purposes including disinfection, oxidation, and microflocculation. When applied, all of these reactions may occur but typically only one is the primary purpose for its use. Ozonation can be used for the removal of color, taste and odors, organics, algae, cyanide, hydrogen sulfide, iron, manganese, and heavy metals. In addition to these treatment processes, ozone is an acceptable alternative to chlorine disinfectants. Given the sophisticated nature of the ozone process, consideration shall be given to the need for maintaining qualified operators to operate and maintain the equipment. The following requirements shall be met:

NR 811.54(1) (1) General. The following general requirements shall be met:

NR 811.54(1)(a) (a) All process designs shall be based on bench or pilot scale studies of dosage requirements, application points, and detention times conducted in accordance with s. NR 811.44.

NR 811.54(1)(b) (b) When ozone is used as a disinfectant, ozonation and detention shall provide the required disinfection CT value. Additionally, application of a disinfectant which maintains a measurable residual in the distribution system shall be required.

NR 811.54(1)(c) (c) Where ozonation is approved by the department to be used for disinfection of a bacteriologically unsafe water supply, duplicate process streams shall be provided. This includes air supply, air preparation equipment, ozone generators, ozone contact chambers, ozone diffusers, power supply, and post disinfection equipment. This requirement may be waived by the department where other acceptable water sources having sufficient capacity are available.

NR 811.54(2) (2) Feed gas preparation. Feed gas can be air, oxygen enriched air, or high purity oxygen. Sources of high purity oxygen include purchased liquid oxygen; on site generation using cryogenic air separation; or temperature, pressure or vacuum swing, adsorptive separation, technology. For high purity oxygen-feed systems, dryers typically are not required. Feed gas preparation shall meet the following requirements:

NR 811.54(2)(a) (a) Air handling equipment. Air handling equipment on conventional low pressure air-feed systems shall consist of an air compressor unless drawn by vacuum, water or air separator, refrigerant and desiccant dryers and particulate filters. For oxygen-feed systems, compressors, separators, and dryers may not be required by the department depending on the purity of the oxygen. In all cases the design shall ensure that the maximum dew point of -60°C (-76°F) will not be exceeded at any time.

NR 811.54(2)(b) (b) Air compression.

NR 811.54(2)(b)1. 1. Air compressors shall be of the liquid-ring or rotary lobe, oil-less, positive displacement type for smaller systems or dry rotary screw compressors for larger systems.

NR 811.54(2)(b)2. 2. The air compressors shall have the capacity to simultaneously provide for maximum ozone demand, provide the air flow required for purging the desiccant dryers, where required, and allow for standby capacity.

NR 811.54(2)(b)3. 3. Air feed for the compressor shall be drawn from a point protected from rain, snow, condensation, mist, and fog to minimize moisture content of the air supply. The air feed shall be protected from contaminated air sources. Outside air intakes shall consist of a downturned pipe elbow installed at a location least susceptible to vandalism and covered with a 24-mesh corrosion resistant screen.

NR 811.54(2)(b)4. 4. A compressed air after-cooler or entrainment separator or both with automatic drain shall be provided prior to the dryers to reduce the water vapor.

NR 811.54(2)(c) (c) Air drying.

NR 811.54(2)(c)1. 1. Dry, dust-free, and oil-free feed gas shall be provided to the ozone generator. Sufficient drying to a maximum dew point of -60°C (-76°F) shall be provided at the end of the drying cycle.