
FROM:	Jeff Coburn  -  RTI International
TO:	Phil Mulrine, EPA/OAQPS
FOR:	EPA Docket No. EPA-HQ-OAR-2019-0373
DATE:	July 3, 2019
SUBJECT:	Control Cost Estimates for Metal HAP Emissions from Iron and Steel Foundries
1.	Purpose
      This memorandum documents the analysis conducted to assess potential additional metal HAP emission control requirements as part of the ample margin of safety assessment for the national emission standards for hazardous air pollutants (NESHAP) for major source iron and steel foundries (40 CFR part 63 subpart EEEEE). 
2.	Background
      Section 112(d)(2) and (3) of the CAA directs the U.S. Environmental Protection Agency (EPA) to develop maximum available control technology (MACT) standards to control hazardous air pollutants (HAP) emissions from major sources. The term "major source" means any stationary source or group of stationary sources located within a contiguous area and under common control that emits or has the potential to emit considering controls, in the aggregate, 10 tons per year or more of any hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants. On April 22, 2004, the EPA published final standards for iron and steel foundries that are major sources of HAP emissions (40 CFR part 63, subpart EEEEE). 
      Section 112(f)(2) of the CAA requires the EPA to determine whether promulgation of additional standards is needed to provide an ample margin of safety to protect public health or to prevent an adverse environmental effect. Section 112(f)(2)(B) of the CAA further expressly preserves the EPA's use of the two-step approach for developing standards to address any residual risk and the Agency's interpretation of "ample margin of safety" developed in the Benzene NESHAP (54 FR 38044, September 14, 1989). In the ample margin of safety assessment, the EPA considers, among other things, additional standards that reduce the number of persons at risk levels higher than approximately 1-in-1 million, taking into account costs and economic impacts, technological feasibility, and other relevant factors.
      Based on the results of the residual risk analysis, several facilities are estimated to have maximum individual risk (MIR)s above 1-in-1 million due to the emissions of metal HAP. The metal HAP that contributed most to elevated risk include hexavalent chromium, nickel, and arsenic. These metal HAP emissions occur from alloying or inoculation (adding specific metals to molten iron or steel to achieve specific properties for the cast part), scrap handling and charging, and ladle transfers and pouring. For ease of reference within this memorandum, we will refer to these as "ancillary sources of metal HAP emissions."  In general, these ancillary sources of metal HAP emissions are "fugitive" in nature. That is, they are not captured and discharged though a conveyance to the atmosphere, but rather emitted through open roof vents or building openings. The emissions from these ancillary sources of metal HAP emissions are currently subject to the building opacity limit in the NESHAP at 40 CFR 63.7690(a)(7). 
3.	Emission Estimates for Ancillary Sources of Metal HAP Emissions
      We used the 2014 national emissions inventory (NEI) data set for iron and steel foundries that was developed for the risk and technology review (EPA, 2019). We filtered this data for just metal HAP and then filtered the data to exclude emissions from direct melting furnaces and combustion units (e.g. steam generating boilers). We determined that the resulting culled data set was a reasonable upper-range estimate of the emissions from ancillary metal HAP emission sources. The facility-wide metal HAP emissions from ancillary sources for each foundry that reported such emissions is provided in Table 1. There are 29 foundries that reported some metal HAP emissions from ancillary sources and 16 foundries that reported metal HAP emissions from ancillary sources of 150 pounds per year (0.075 tons/yr) or more (shaded facilities in Table 1). The total nationwide metal HAP emissions for ancillary sources were estimated to be 5.09 tons/yr, with an average foundry emission rate of 0.175 tons/yr (5.088/29). The average estimated metal HAP emissions rate from ancillary sources at the 16 foundries with reported ancillary emissions of 150 pounds per year or more is 0.293 tons/year (4.685/16).
4.	Control Cost Estimates for Metal HAP Emissions from Ancillary Sources 
      Reducing the emissions from ancillary sources of metal HAP would require installing and operating capture systems (e.g., hooding, duct work, fans, etc.) that direct the emissions to a particulate control device (e.g., scrubber or baghouse). In some applications, an existing particulate control device may have adequate capacity for handling the additional gas stream load, but in general, we expect that a new particulate control device would be required due to the relatively large volumes of air that may need to be collected. Most iron and steel foundries use baghouse control systems for their particulate matter control; therefore, we estimated the costs based on installing new hooding, duct work, fans and a relatively small baghouse specifically to control these ancillary sources of metal HAP emissions.
      Key parameters needed to develop the control costs for a fabric filter control system, commonly referred to as a baghouse, include the volumetric flow rate, application type, and the number of hours the source is operated per year. The volumetric flow rate of gas to be treated is dependent on the size of the source and the ability to provide a close capture hooding system. If the emission source can be enclosed or the capture system is located very near the source, less volume of gas is needed to ensure good capture of emissions. If a side draft hood or canopy hood well above the source is used, more air flow is needed for good capture. Because this analysis focuses on applying controls to existing sources, we expect that side draft hooding or canopy hooding somewhat removed from the source would be needed, resulting in higher volumes of gas collected and routed to the baghouse.
Table 1. Reported Metal HAP Emissions Estimates from Ancillary Sources by Foundry
                                 Facility Name
                                     City
                                     State
             Metal HAP Emissions from Ancillary Sources (tons/yr)
 John Deere Foundry Waterloo
Waterloo
                                      IA
     1.04
 DMI Columbus, LLC
Columbus
                                      GA
     0.4625
 U. S. Pipe & Foundry Company, LLC
Bessemer
                                      AL
     0.4384
 Nidec Minster Corporation
Minster
                                      OH
     0.3915
 Magotteaux Pulaski
Pulaski
                                      TN
     0.3106
 Waupaca Foundry Inc -Plant 4
Marinette
                                      WI
     0.3034
 Esco Corporation
Portland
                                      OR
     0.2783
 Liberty Casting Co.
Delaware
                                      OH
     0.2675
 Dalton Corporation Warsaw Manufacturing
Warsaw
                                      IN
     0.2284
 McWane
Tyler
                                      TX
     0.2113
 Alliance Casting Co. LLC 
Alliance
                                      OH
     0.1946
 Clow Valve Company - Foundry
Oskaloosa
                                      IA
     0.1840
 Bradken - Atchison/St. Joseph
Atchison
                                      KS
     0.09783
 Waupaca Foundry Inc Plant 1
Waupaca
                                      WI
     0.09279
 Metal Technologies Auburn LLC
Auburn
                                      IN
     0.09206
 Waupaca Foundry Inc
Tell City
                                      IN
     0.09176
 Ardmore Foundry
Ardmore
                                      OK
     0.07
 Waupaca Foundry Inc-Plants 2 / 3
Waupaca
                                      WI
     0.05783
 Harrison Steel Castings Company
Attica
                                      IN
     0.05521
 Aarrowcast Inc
Shawano
                                      WI
     0.05470
 Neenah Foundry Co - Plants 2 and 3 
Neenah
                                      WI
     0.05102
 Grede LLC
New Castle
                                      IN
     0.04395
 Quality Electric Steel Castings
Houston
                                      TX
     0.0255
 Intat Precision Incorporated
Rushville
                                      IN
     0.01470
 Rochester Metal Products Corp
Rochester
                                      IN
     0.01209
 American Cast Iron Pipe Company
Birmingham
                                      AL
     0.01034
 Ward Mfg Llc/Blossburg Plts 1-3
Blossburg
                                      PA
     0.00548
 Cadillac Casting, Inc
Cadillac
                                      MI
     0.00171
 Caterpillar Inc
Mapleton
                                      IL
     0.000935
      
      For this screening analysis, we assumed the capture system would have a flow rate of between 40,000 actual cubic feet per minute (acfm) and 80,000 acfm, depending on the size, configuration, and number of the ancillary metal HAP emissions sources present at the foundry. We assumed that all ancillary emission sources could be ducted to a single control system. We assumed the capture system and control device would operate 4,000 hours per year.  
      We developed capital investment and total annualized costs for two modular pulse-jet baghouse systems using the methods provided in the EPA Air Pollution Control Cost Manual (U.S. EPA, 2002): one system with a design capacity or 40,000 acfm and one system with a design capacity or 80,000 acfm. Costs for pulse-jet systems were used because they are commonly used at foundries and they are generally less costly than shaker or reverse-air systems because they can achieve high removal efficiencies with higher gas-to-cloth ratios. We used a material factor of 9.0 (for metal powder) and an application factor of 0.8 (process gas filtration), which resulted in a design gas-to-cloth ratio of 7.66 acfm/ft[2]. Capital costs were escalated to 2017 dollars, and a retrofit factor of 1.3 was applied to the capital costs to account for additional costs associated with retrofitting the control system to an existing plant. An equipment life of 20 years was assumed along with a bag life of 2 years. The capital costs were annualized using a 5 percent annual interest rate. Operating costs were based on 2017 values summarized in Table 2.
               Table 2. Summary of 2017 Utility and Labor Rates
      Description
   Cost
    Units
 Electricity 
 $0.0688
 per kWh
 Compressed Air 
 $0.25
 per 1,000 scf
 Operator Labor Rate
 $27.48
 per hour
 Maintenance Labor Rate
 $30.23
 per hour
 Dust Disposal Cost 
 $0.05
 per ton
      
      The projected capital and annualized costs for the model capture and baghouse control systems are summarized in Table 3. 
              Table 3. Cost Estimates for Model Baghouse Systems
                             Model Control System
                            Design Flow Rate (acfm)
                            Total Capital Cost ($)
                         Total Annualized Cost ($/yr)
                          Electricity Use (kW-hr/yr)
                                Small Baghouse
                                    40,000
                                    607,000
                                    146,000
                                    187,100
                                Large Baghouse
                                    80,000
                                   1,013,000
                                    270,000
                                    374,200
      
      Because the flow rate of the capture system is more dependent on the configuration of the capture system than the total amount of PM or metal HAP emitted, we did not assign foundries to the model plants based on the reported HAP emissions. Instead, we assumed that approximately half of the foundries would have a 40,000 acfm system and the other half would have an 80,000 acfm system. More specifically, considering 29 foundries with metal HAP emissions from ancillary sources, we assigned 15 foundries to the 40,000 acfm system and 14 foundries to the 80,000 acfm system. Table 4 summarizes the development of nationwide costs when considering all foundries with ancillary metal HAP emissions sources. 
      Table 4. Development of Nationwide Cost Estimates for all Foundries
                             Model Control System
                           No. of Foundries Assigned
                       Aggregate Total Capital Cost ($)
                    Aggregate Total Annualized Cost ($/yr)
                                Small Baghouse
                                      15
                                   9,102,000
                                   2,189,000
                                Large Baghouse
                                      14
                                  14,186,000
                                   3,777,000
                                  Nationwide
                                      29
                                  23,288,000
                                   5,966,000
      
      We also assessed the nationwide costs of a targeted regulatory option that only required control of ancillary sources if these sources had combined emissions of more than 150 lbs/yr. We again assumed half (8) of the foundries could use the 40,000 acfm system and the other half (8) would need the 80,000 acfm system. Table 5 summarizes the development of the nationwide costs of a targeted regulation for sources with high metal HAP emissions from ancillary sources.
   Table 5. Development of Nationwide Cost Estimates for Targeted Regulation
                             Model Control System
                           No. of Foundries Assigned
                       Aggregate Total Capital Cost ($)
                    Aggregate Total Annualized Cost ($/yr)
                                Small Baghouse
                                       8
                                   4,854,000
                                   1,167,000
                                Large Baghouse
                                       8
                                   8,106,000
                                   2,158,000
                                  Nationwide
                                      16
                                  12,960,000
                                   3,326,000
      
      Baghouses can generally achieve 99 percent reduction in PM and metal HAP emissions. However, for these ancillary sources, the capture system will likely limit the overall control efficiency of the system. For this analysis, we assumed an overall capture and control system would achieve a 90 percent reduction in metal HAP emissions. Table 6 provides a summary of the cost effectiveness for a general and a targeted regulation for controlling ancillary sources of metal HAP emissions.
     Table 6. Summary of Cost Effectiveness for Metal HAP Control Options
                                Control Option
                       Nationwide Total Capital Cost ($)
                    Nationwide Total Annualized Cost ($/yr)
                    Metal HAP Emission Reduction (tons/yr)
                 Cost Effectiveness ($/ton metal HAP reduced)
                                 All Foundries
                                  23,290,000
                                   5,970,000
                                     4.58
                                   1,300,000
                           Foundries >= 150 lbs/yr
                                  12,960,000
                                   3,330,000
                                     4.22
                                    790,000
      
5.	References
U.S. Environmental Protection Agency. 2002. EPA Air Pollution Control Cost Manual. 6th Edition. EPA/452/B-02-001. Baghouses and Filters. Section 6, Chapter 1 (chapter dated December 1998). Available at:  https://www3.epa.gov/ttncatc1/dir1/c_allchs.pdf 
U.S. Environmental Protection Agency. 2019. Residual Risk Assessment for Iron and Steel Foundries Source Category in Support of the 2019 Risk and Technology Review Proposed Rule, Appendix 1. In Docket ID No. EPA-HQ-OAR-2019-0373.
