Chapter NR 666

where:

n = number of carcinogenic metals

NR 666.106(4)(d) (d) Noncarcinogenic metals. For the noncarcinogenic metals, the predicted maximum annual average off-site ground level concentration for each metal may not exceed the reference air concentration (RAC).

NR 666.106(4)(e) (e) Multiple stacks. Owners and operators of facilities with more than one on-site stack from a boiler, industrial furnace, incinerator or other thermal treatment unit subject to controls on metals emissions under an operating license or interim license shall conduct emissions testing (except that facilities complying with adjusted Tier I controls need not conduct emissions testing) and dispersion modeling to demonstrate that the aggregate emissions from all such on-site stacks do not result in an exceedance of the acceptable ambient levels.

NR 666.106(4)(f) (f) Implementation. Under Tier III, the metals controls shall be implemented by limiting feed rates of the individual metals to levels during the trial burn (for new facilities or an interim license facility applying for an operating license) or the compliance test (for interim license facilities). The feed rate averaging periods are the same as provided by sub. (2) (a) 1. and 2. and (b) 2. The feed rate of metals in each feedstream shall be monitored to ensure that the feed rate limits for the feedstreams specified under s. NR 666.102 or 666.103 are not exceeded.

NR 666.106(5) (5) Adjusted Tier 1 feed rate screening limits. The owner or operator may adjust the feed rate screening limits provided by ch. NR 666 Appendix I to account for site-specific dispersion modeling. Under this approach, the adjusted feed rate screening limit for a metal is determined by back-calculating from the acceptable ambient level provided by ch. NR 666 Appendix IV and ch. NR 666 Appendix V using dispersion modeling to determine the maximum allowable emission rate. This emission rate becomes the adjusted Tier I feed rate screening limit. The feed rate screening limits for carcinogenic metals are implemented as prescribed in sub. (2) (b).

NR 666.106(6) (6) Alternative implementation approaches.

NR 666.106(6)(a) (a) The department may approve on a case-by-case basis approaches to implement the Tier II or Tier III metals emission limits provided by sub. (3) or (4) alternative to monitoring the feed rate of metals in each feedstream.

NR 666.106(6)(b) (b) The emission limits provided by sub. (4) shall be determined as follows:

NR 666.106(6)(b)1. 1. For each noncarcinogenic metal, by back-calculating from the RAC provided in ch. NR 666 Appendix IV to determine the allowable emission rate for each metal using the dilution factor for the maximum annual average ground level concentration predicted by dispersion modeling in conformance with sub. (8).

NR 666.106(6)(b)2. 2. For each carcinogenic metal by all of the following:

NR 666.106(6)(b)2.a. a. Back-calculating from the RSD provided in ch. NR 666 Appendix V to determine the allowable emission rate for each metal if that metal were the only carcinogenic metal emitted using the dilution factor for the maximum annual average ground level concentration predicted by dispersion modeling in conformance with sub. (8).

NR 666.106(6)(b)2.b. b. If more than one carcinogenic metal is emitted, selecting an emission limit for each carcinogenic metal not to exceed the emission rate determined by subd. 2. a. such that the sum for all carcinogenic metals of the ratios of the selected emission limit to the emission rate determined by subd. 2. a. does not exceed 1.0.

NR 666.106(7) (7) Emission testing.

NR 666.106(7)(a) (a) General. Emission testing for metals shall be conducted using Method 0060, Determinations of Metals in Stack Emissions, EPA SW-846, as incorporated by reference in s. NR 660.11.

NR 666.106(7)(b) (b) Hexavalent chromium. Emissions of chromium are assumed to be hexavalent chromium unless the owner or operator conducts emissions testing to determine hexavalent chromium emissions using procedures prescribed in Method 0061, Determination of Hexavalent Chromium Emissions from Stationary Sources, EPA SW-846, as incorporated by reference in s. NR 660.11.

NR 666.106(8) (8) Dispersion Modeling. Dispersion modeling required under this section shall be conducted according to methods recommended in Appendix W of 40 CFR part 51 (”Guideline on Air Quality Models (Revised)” (1986) and its supplements, incorporated by reference in s. NR 660.11), the “Hazardous Waste Combustion Air Quality Screening Procedure”, provided in ch. NR 666 Appendix IX , or in Screening Procedures for Estimating the Air Quality Impact of Stationary Sources, Revised, EPA-450/R-92-019, incorporated by reference in s. NR 660.11, to predict the maximum annual average off-site ground level concentration. However, on-site concentrations shall be considered when a person resides on-site.

NR 666.106(9) (9) Enforcement. For the purposes of license enforcement, compliance with the operating requirements specified in the license (under s. NR 666.102) shall be regarded as compliance with this section. However, evidence that compliance with those license conditions is insufficient to ensure compliance with this section may be information justifying modification or revocation and re-issuance of a license under s. NR 670.041.

NR 666.106 History History: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06; corrections in (2) (intro.), (a), (b) 1., (c), (e), (3) (intro.), (a), (b), (4) (b), (5), (6) (b) 1., 2. a., (8) made under s. 13.92 (4) (b) 7., Stats., Register March 2013 No. 687; CR 16-007: am. (1) Register July 2017 No. 739, eff. 8-1-17.

NR 666.107 NR 666.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

NR 666.107(1) (1) General. The owner or operator shall comply with the hydrogen chloride (HCl) and chlorine (Cl2) controls provided by sub. (2), (3) or (5).

NR 666.107(2) (2) Screening limits.

NR 666.107(2)(a) (a) Tier I feed rate screening limits. Feed rate screening limits are specified for total chlorine in ch. NR 666 Appendix II as a function of terrain-adjusted effective stack height and terrain and land use in the vicinity of the facility. The feed rate of total chlorine and chloride, both organic and inorganic, in all feed streams, including hazardous waste, fuels and industrial furnace feed stocks may not exceed the levels specified.

NR 666.107(2)(b) (b) Tier II emission rate screening limits. Emission rate screening limits for HCl and Cl2 are specified in ch. NR 666 Appendix III as a function of terrain-adjusted effective stack height and terrain and land use in the vicinity of the facility. The stack emission rates of HCl and Cl2 may not exceed the levels specified.

NR 666.107(2)(c) (c) Definitions and limitations. The definitions and limitations provided by s. NR 666.106 (2) for the following terms also apply to the screening limits provided by this subsection: terrain-adjusted effective stack height, good engineering practice stack height, terrain type, land use and criteria for facilities not eligible to use the screening limits.

NR 666.107(2)(d) (d) Multiple stacks. Owners and operators of facilities with more than one on-site stack from a boiler, industrial furnace, incinerator or other thermal treatment unit subject to controls on HCl or Cl2 emissions under an operating license or interim license shall comply with the Tier I and Tier II screening limits for those stacks assuming all hazardous waste is fed into the device with the worst-case stack based on dispersion characteristics.

NR 666.107(2)(d)1. 1. The worst-case stack is determined by procedures provided in s. NR 666.106 (2) (f).

NR 666.107(2)(d)2. 2. Under Tier I, the total feed rate of chlorine and chloride to all subject devices may not exceed the screening limit for the worst-case stack.

NR 666.107(2)(d)3. 3. Under Tier II, the total emissions of HCl and Cl2 from all subject stacks may not exceed the screening limit for the worst-case stack.

NR 666.107(3) (3) Tier III site-specific risk assessments.

NR 666.107(3)(a) (a) General. Conformance with the Tier III controls shall be demonstrated by emissions testing to determine the emission rate for HCl and Cl2, air dispersion modeling to predict the maximum annual average off-site ground level concentration for each compound, and a demonstration that acceptable ambient levels are not exceeded.

NR 666.107(3)(b) (b) Acceptable ambient levels. Chapter. NR 666 Appendix IV lists the reference air concentrations (RACs) for HCl (7 micrograms per cubic meter) and Cl2 (0.4 micrograms per cubic meter).

NR 666.107(3)(c) (c) Multiple stacks. Owners and operators of facilities with more than one on-site stack from a boiler, industrial furnace, incinerator or other thermal treatment unit subject to controls on HCl or Cl2 emissions under an operating license or interim license shall conduct emissions testing and dispersion modeling to demonstrate that the aggregate emissions from all such on-site stacks do not result in an exceedance of the acceptable ambient levels for HCl and Cl2.

NR 666.107(4) (4) Averaging periods. The HCl and Cl2 controls are implemented by limiting the feed rate of total chlorine and chloride in all feedstreams, including hazardous waste, fuels and industrial furnace feed stocks. Under Tier I, the feed rate of total chloride and chlorine is limited to the Tier I screening limits. Under Tier II and Tier III, the feed rate of total chloride and chlorine is limited to the feed rates during the trial burn (for new facilities or an interim license facility applying for a license) or the compliance test (for interim license facilities). The feed rate limits are based on either of the following:

NR 666.107(4)(a) (a) An hourly rolling average as defined in s. NR 666.102 (5) (f).

NR 666.107(4)(b) (b) An instantaneous basis not to be exceeded at any time.

NR 666.107(5) (5) Adjusted Tier I feed rate screening limits. The owner or operator may adjust the feed rate screening limit provided by ch. NR 666 Appendix II to account for site-specific dispersion modeling. Under this approach, the adjusted feed rate screening limit is determined by back-calculating from the acceptable ambient level for Cl2 provided by ch. NR 666 Appendix IV using dispersion modeling to determine the maximum allowable emission rate. This emission rate becomes the adjusted Tier I feed rate screening limit.

NR 666.107(6) (6) Emissions testing. Emissions testing for HCl and Cl2 shall be conducted using the procedures described in Methods 0050 or 0051, EPA SW-846, as incorporated by reference in s. NR 660.11.

NR 666.107(7) (7) Dispersion modeling. Dispersion modeling shall be conducted according to s. NR 666.106 (8).

NR 666.107(8) (8) Enforcement. For the purposes of license enforcement, compliance with the operating requirements specified in the license (under s. NR 666.102) shall be regarded as compliance with this section. However, evidence that compliance with those license conditions is insufficient to ensure compliance with this section may be information justifying modification or revocation and re-issuance of a license under s. NR 670.041.

NR 666.107 History History: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06; corrections in (2) (a), (b), (3) (b), (5) made under s. 13.92 (4) (b) 7., Stats., Register March 2013 No. 687.

NR 666.108 NR 666.108 Small quantity on-site burner exemption.

NR 666.108(1) (1) Exempt quantities. Owners and operators of facilities that burn hazardous waste in a non-site boiler or industrial furnace are exempt from this subchapter if all of the following conditions are met:

NR 666.108(1)(a) (a) The quantity of hazardous waste burned in a device for a calendar month does not exceed the limits provided in the following table based on the terrain-adjusted effective stack height as defined in s. NR 666.106 (2) (c).

NR 666.108(1)(b) (b) The maximum hazardous waste firing rate does not exceed at any time one percent of the total fuel requirements for the device (hazardous waste plus other fuel) on a total heat input or mass input basis, whichever results in the lower mass feed rate of hazardous waste.

NR 666.108(1)(c) (c) The hazardous waste has a minimum heating value of 5,000 Btu/lb, as generated.

NR 666.108(1)(d) (d) The hazardous waste fuel does not contain (and is not derived from) EPA hazardous waste numbers F020, F021, F022, F023, F026 or F027.

NR 666.108(2) (2) Mixing with nonhazardous fuels. If hazardous waste fuel is mixed with a nonhazardous fuel, the quantity of hazardous waste before such mixing is used to comply with sub. (1).

NR 666.108(3) (3) Multiple stacks. If an owner or operator burns hazardous waste in more than one on-site boiler or industrial furnace exempt under this section, the quantity limits provided by sub. (1) (a) are implemented according to the following equation:

£

å

=

where:

n means the number of stacks.

Actual Quantity Burned means the waste quantity burned per month in device “i”.

Allowable Quantity Burned means the maximum allowable exempt quantity for stack “i” from the table in sub. (1) (a).

NR 666.108 Note Note: Hazardous wastes that are subject to the special requirements for small quantity generators under ss. NR 662.013 and 662.016 may be burned in an off-site device under the exemption provided by this section, but shall be included in the quantity determination for the exemption.

NR 666.108(4) (4) Notification requirements. The owner or operator of facilities qualifying for the small quantity burner exemption under this section shall provide a one-time signed, written notice to the department indicating all of the following:

NR 666.108(4)(a) (a) The combustion unit is operating as a small quantity burner of hazardous waste.

NR 666.108(4)(b) (b) The owner and operator are in compliance with this section.

NR 666.108(4)(c) (c) The maximum quantity of hazardous waste that the facility may burn per month as provided by sub. (1) (a).

NR 666.108(5) (5) Recordkeeping requirements. The owner or operator shall maintain at the facility for at least 3 years sufficient records documenting compliance with the hazardous waste quantity, firing rate and heating value limits of this section. At a minimum, these records shall indicate the quantity of hazardous waste and other fuel burned in each unit per calendar month, and the heating value of the hazardous waste.

NR 666.108 History History: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06.

NR 666.109 NR 666.109 Low risk waste exemption.

NR 666.109(1) (1) Waiver of DRE standard. The DRE standard of s. NR 666.104 (1) does not apply if the boiler or industrial furnace is operated in conformance with par. (a) and the owner or operator demonstrates by procedures prescribed in par. (b) that the burning will not result in unacceptable adverse health effects.

NR 666.109(1)(a) (a) The device shall be operated with all of the following conditions:

NR 666.109(1)(a)1. 1. A minimum of 50% of fuel fired to the device shall be fossil fuel, fuels derived from fossil fuel, tall oil, or, if approved by the department on a case-by-case basis, other nonhazardous fuel with combustion characteristics comparable to fossil fuel. Such fuels are termed primary fuel for purposes of this section. (Tall oil is a fuel derived from vegetable and rosin fatty acids.) The 50% primary fuel firing rate shall be determined on a total heat or mass input basis, whichever results in the greater mass feed rate of primary fuel fired.

NR 666.109(1)(a)2. 2. Primary fuels and hazardous waste fuels shall have a minimum as-fired heating value of 8,000 Btu/lb.

NR 666.109(1)(a)3. 3. The hazardous waste shall be fired directly into the primary fuel flame zone of the combustion chamber.

NR 666.109(1)(a)4. 4. The device shall operate in conformance with the carbon monoxide controls provided by s. NR 666.104 (2) (a). Devices subject to the exemption provided by this section are not eligible for the alternative carbon monoxide controls provided by s. NR 666.104 (3).

NR 666.109(1)(b) (b) Procedures to demonstrate that the hazardous waste burning will not pose unacceptable adverse public health effects are all of the following:

NR 666.109(1)(b)1. 1. Identify and quantify those nonmetal compounds listed in ch. NR 661 Appendix VIII that could reasonably be expected to be present in the hazardous waste. The constituents excluded from analysis shall be identified and the basis for their exclusion explained.

NR 666.109(1)(b)2. 2. Calculate reasonable, worst case emission rates for each constituent identified in subd. 1. by assuming the device achieves 99.9% destruction and removal efficiency. That is, assume that 0.1% of the mass weight of each constituent fed to the device is emitted.

NR 666.109(1)(b)3. 3. For each constituent identified in subd. 1., use emissions dispersion modeling to predict the maximum annual average ground level concentration of the constituent.

NR 666.109(1)(b)3.a. a. Dispersion modeling shall be conducted using methods specified in s. NR 666.106 (8).

NR 666.109(1)(b)3.b. b. Owners and operators of facilities with more than one on-site stack from a boiler or industrial furnace that is exempt under this section shall conduct dispersion modeling of emissions from all stacks exempt under this section to predict ambient levels prescribed by this subdivision.

NR 666.109(1)(b)4. 4. Ground level concentrations of constituents predicted under subd. 3. may not exceed all of the following levels:

NR 666.109(1)(b)4.a. a. For the noncarcinogenic compounds listed in ch. NR 666 Appendix IV, the levels established in ch. NR 666 Appendix IV.

NR 666.109(1)(b)4.b. b. For the carcinogenic compounds listed in ch. NR 666 Appendix V, the sum for all constituents of the ratios of the actual ground level concentration to the level established in ch. NR 666 Appendix V cannot exceed 1.0.

NR 666.109(1)(b)4.c. c. For constituents not listed in ch. NR 666 Appendix IV or V, 0.1 micrograms per cubic meter.

NR 666.109(2) (2) Waiver of particular matter standard. The particulate matter standard of s. NR 666.105 does not apply if both of the following conditions are met:

NR 666.109(2)(a) (a) The DRE standard is waived under sub. (1).

NR 666.109(2)(b) (b) The owner or operator complies with the Tier I or adjusted Tier I metals feed rate screening limits provided by s. NR 666.106 (2) or (5).

NR 666.109 History History: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06; corrections in (1) (b) 4. a. to c. made under s. 13.92 (4) (b) 7., Stats., Register March 2013 No. 687.

NR 666.110 NR 666.110 Waiver of DRE trial burn for boilers. Boilers that operate under the special requirements of this section, and that do not burn hazardous waste containing (or derived from) EPA hazardous waste numbers F020, F021, F022, F023, F026 or F027, are considered to be in conformance with the DRE standard of s. NR 666.104 (1), and a trial burn to demonstrate DRE is waived. When burning hazardous waste, all of the following apply:

NR 666.110(1) (1) A minimum of 50% of fuel fired to the device shall be fossil fuel, fuels derived from fossil fuel, tall oil, or, if approved by the department on a case-by-case basis, other nonhazardous fuel with combustion characteristics comparable to fossil fuel. Such fuels are termed primary fuel for purposes of this section. (Tall oil is a fuel derived from vegetable and rosin fatty acids.) The 50% primary fuel firing rate shall be determined on a total heat or mass input basis, whichever results in the greater mass feed rate of primary fuel fired.

NR 666.110(2) (2) Boiler load may not be less than 40%. Boiler load is the ratio at any time of the total heat input to the maximum design heat input.

NR 666.110(3) (3) Primary fuels and hazardous waste fuels shall have a minimum as-fired heating value of 8,000 Btu/lb, and each material fired in a burner where hazardous waste is fired shall have a heating value of at least 8,000 Btu/lb, as-fired.

NR 666.110(4) (4) The device shall operate in conformance with the carbon monoxide standard provided by s. NR 666.104 (2) (a). Boilers subject to the waiver of the DRE trial burn provided by this section are not eligible for the alternative carbon monoxide standard provided by s. NR 666.104 (3).

NR 666.110(5) (5) The boiler shall be a watertube type boiler that does not feed fuel using a stoker or stoker type mechanism.

NR 666.110(6) (6) The hazardous waste shall be fired directly into the primary fuel flame zone of the combustion chamber with an air or steam atomization firing system, mechanical atomization system, or a rotary cup atomization system under any of the following conditions: