ERSL = emission rate screening limit provided by ch. NR 666 Appendix I for metal “i”
NR 666.106(3)(c)(c) Implementation. The emission rate limits 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 a 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(3)(d)(d) Definitions and limitations. The definitions and limitations provided by sub. (2) for the following terms also apply to the Tier II emission rate 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 666.106(3)(e)(e) Multiple stacks.
NR 666.106(3)(e)1.1. Owners and operators of facilities with more than one onsite 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 comply with the emissions screening limits for any such stacks assuming all hazardous waste is fed into the device with the worst-case stack based on dispersion characteristics.
NR 666.106(3)(e)2.2. The worst-case stack is determined by procedures provided in sub. (2) (f).
NR 666.106(3)(e)3.3. For each metal, the total emissions of the metal from those stacks may not exceed the screening limit for the worst-case stack.
NR 666.106(4)(4)Tier III and adjusted Tier I site-specific risk assessment. The requirements of this subsection apply to facilities complying with either the Tier III or adjusted Tier I controls, except where specified otherwise.
NR 666.106(4)(a)(a) General. Conformance with the Tier III metals controls shall be demonstrated by emissions testing to determine the emission rate for each metal. In addition, conformance with either the Tier III or adjusted Tier I metals controls shall be demonstrated by air dispersion modeling to predict the maximum annual average off-site ground level concentration for each dispersion modeling to predict the maximum annual average off-site ground level concentration for each metal, and a demonstration that acceptable ambient levels are not exceeded.
NR 666.106(4)(b)(b) Acceptable ambient levels. Chapter NR 666 Appendix IV and ch. NR 666 Appendix V list the acceptable ambient levels for purposes of this rule. Reference air concentrations (RACs) are listed for the noncarcinogenic metals and 10–5 risk-specific doses (RSDs) are listed for the carcinogenic metals. The RSD for a metal is the acceptable ambient level for that metal if only one of the 4 carcinogenic metals is emitted. If more than one carcinogenic metal is emitted, the acceptable ambient level for the carcinogenic metals is a fraction of the RSD as described in par. (c).
NR 666.106(4)(c)(c) Carcinogenic metals. For the carcinogenic metals, arsenic, cadmium, beryllium and chromium, the sum of the ratios of the predicted maximum annual average off-site ground level concentrations (except that on-site concentrations shall be considered if a person resides on site) to the risk-specific dose (RSD) for all carcinogenic metals emitted may not exceed 1.0 as determined by the following equation:
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=
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-
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.