NR 110.19(7)(7)Structural features.
NR 110.19(7)(a)(a) Mercury seals. Mercury seals may not be used on trickling filter distributors. Mercury seals shall be removed from existing filters during renovation. Mercury seals removed from existing filters during renovation or destruction of the filter shall be disposed in a location and manner approved by the department.
NR 110.19(7)(b)(b) Depth of media. Rock or slag filter media, or loose synthetic media, shall have a minimum depth of 1.5 meters (5 feet) above the underdrains. Synthetic corrugated filter media should have a minimum depth of 3 meters (10 feet) to provide adequate contact time with the wastewater. Rock or slag filter media depths may not exceed 3 meters (10 feet) and synthetic filter media depths may not exceed 9.1 meters (30 feet) except where special construction is justified through pilot studies.
NR 110.19(7)(c)(c) Covers. Covers shall be provided on all filters to prevent icing and freezing and to increase the treatment efficiency of the filter during winter conditions.
NR 110.19(7)(d)(d) Ventilation.
NR 110.19(7)(d)1.1. The underdrainage system, effluent channels, and effluent pipe shall be designed to permit free passage of air. The size of drains, channels and pipe shall be such that not more than 50% of their cross-sectional area will be submerged under the maximum daily design hydraulic loading. The design of the effluent channels should consider the probability of increased hydraulic loading.
NR 110.19(7)(d)2.2. Filter covers shall be designed to allow adequate ventilation to maintain the filter in an aerobic state at all times.
NR 110.19(7)(e)(e) Maintenance. All distribution devices, underdrains, channels and pipes shall be installed so that they may be properly maintained, flushed and drained.
NR 110.19(7)(f)(f) Flow measurement. Devices shall be provided to permit measurement of flow to the filter, including the amount of recirculated flow.
NR 110.19 HistoryHistory: Cr. Register, November, 1974, No. 227, eff. 12-1-74; r. and recr. Register, February, 1983, No. 326, eff. 3-1-83; CR 09-123: am. (5) (b) 2. and (6) (b) 1. Register July 2010 No. 655, eff. 8-1-10.
NR 110.20NR 110.20Rotating biological contactors.
NR 110.20(1)(1)General.
NR 110.20(1)(a)(a) Applicability. Rotating biological contactors may be used when the wastewater is amenable to biological treatment. This treatment process may be used for carbonaceous or nitrogenous oxygen demand reduction, or both.
NR 110.20(1)(b)(b) Manufacturer’s warranty. Manufacturers of rotating biological contactor equipment shall guarantee the rotating shafts, and media against failure during the initial 5 years of operation for all proposed rotating biological contactor treatment systems. The guarantee shall include equipment replacement and installation costs.
NR 110.20(2)(2)Design considerations.
NR 110.20(2)(a)(a) Design report. A design report for rotating biological contactors shall be submitted in accordance with s. NR 110.15 (1).
NR 110.20(2)(b)(b) Design parameters. The design of rotating biological contactors shall consider:
NR 110.20(2)(b)1.1. Design flow rate;
NR 110.20(2)(b)2.2. Influent carbonaceous and nitrogenous biochemical oxygen demand;
NR 110.20(2)(b)3.3. Rotational velocity;
NR 110.20(2)(b)4.4. Wastewater temperature; and
NR 110.20(2)(b)5.5. Percent influent biochemical oxygen demand which is soluble.
NR 110.20(3)(3)Design features.
NR 110.20(3)(a)(a) Primary treatment. Rotating biological contactors shall be preceded by primary treatment.
NR 110.20(3)(b)(b) Contact tanks.
NR 110.20(3)(b)1.1. Contact tanks shall be sized to maintain a maximum hydraulic detention time of 100 minutes.
NR 110.20(3)(b)2.2. Tanks shall contain positive liquid level control so that the rotating biological contactors will remain approximately 40% submerged.
NR 110.20(3)(b)3.3. Contact tanks and rotating shafts shall be enclosed. The enclosure shall be ventilated.
NR 110.20(3)(b)4.4. Removable baffles shall be provided between contact stages.