1 

### MEMORANDUM

DATE: Ma y 2 2

, 201 5

SUBJECT: Revised MACT Floor Analysis for the Ferroalloys Production Source Category

FROM: Bradley Nelson, EC/R, Inc.

TO: Phil Mulrine , EPA OAQPS/SPPD/ M ICG

1.0 PURPOSE

The purpose of this memorandum is to document the results of the revised maximum achievable

control technology (MACT) floor determination for mercury (H g ), and total polycyclic aromatic

hydrocarbons (PAH) for the f erroalloys p roduction source category and Beyond the Floor (BTF)

analyses . The MACT floor determinations for each of these p o llutants were re

- evaluated

incorporating newly provided test data 1

, 2 

### received prior to and after the publication of the 201 4

supplemental propos ed amendments to the national emission standards for hazardous air pollutants

(NESHAP) for the ferroalloys production source category

, published in the Federal Register on

October 10 , 201 4 (7 9 FR 60238 ). This additional test data was rec eived from one of the facilities,

and provides additional HAP data for some pollutants at previously tested emission sources

, including PAH and Hg data from each of the operational furnaces at a single facility , one furnace

producing FerroManganese (FeMn) and the other producing SilicoManganese (SiMN)

.

Based on the inclusion of the new test data, EPA decided to re

- evaluate the emission limits for the

final amendments to the NESHAP. This memorandum describes the re

- evaluation and revisions to

the PAH and H g emissions limits for new and existing sources . The new test data included only

PAH and Hg emissions, and thus did not warrant any changes to the previously propose d emission

limit s for other pollutants

. B ackground information, facility summaries, deta ils of previously

proposed limits, and detail s of methodology are unchanged from those described in MACT Floor

memorandum supporting the supplemental proposal and thus is not included here

. 3

1 "Emission Measurement Summary Report Furnace No. 12 Scrubber PAHs and Mercury Eramet Marietta Inc.
Marietta, OH", January 2013

. 2 "Polycyclic Aromatic Hydrocarbons and Mercury Emission Summary Report EAF No. 12 Scrubber EAF No. 1 Baghouse Eramet Marietta Inc . Marietta, OH"

. 3 Memorandum from Bradley Nelson, EC/R to Phil Mulrine, EPA OAQPS/SPPD/MICG

, Revised MACT Floor Analysis for the Ferroalloys Production Source Category, August 29, 2014, EPA

- HQ

- OAR

- 2010

- 0895

- 0174.2 

### 2 .0 SUMMARY OF PROPOSED MACT LIMITS

A summary of the prop osed emission standards as they stand after the supplemental proposal of

amendments to the Ferroalloys NESHAP published in the Federal Register on October 10 , 201 4 (7 9

FR 60238 ) is presented in Table 2

- 1

. With the exception of the revisions detailed in the following

sections, these will be the final MACT emission limits.

3 .0 MACT DETERMINATION FOR FERROALLOYS SOURCE CATEGORY

Emissions data for each of the furnaces were obtained from the facilities from Information

Collection Requests (ICR) in 2010 and 2012 and from stack test submittals by the facilities. The

individual test reports submitted by the facilities can b e found in the docket for this rulemaking

( EPA

- HQ

- OAR

- 2010

- 0895 )

. For PAH, the test data from the 2010 ICR were collected using EPA

Method 0010, whereas test data from the 2012 ICR and other submitted test reports were collected

using California Air Resources Board Method 429 (CARB 429). The PAH test results from the two
test methods were considered to be comparable and were used in the MACT Floor analysis. The

test data for Hg was collected using either EPA Method 29 or 30b.

The following sections summarize the approach in determining the revised PAH and Hg MACT

fl oors for the Ferroalloys Production source category using the upper prediction limit (UPL) using

the guidelines provided in the UPL memorandum. For datasets (for the development of a specific

emissions limit) that consisted of at least 3 test runs but few er than 7 test runs, an approach

developed for limited datasets was used to calulate the UPL. 4



### Furnace test data submitted by Eramet for testing conducted in July 2012 were not included in the

MACT Floor analysis for PAH. These data consisted of only one run each from both Furnaces 1

and 12 and one run from the Furnace 1 tapping baghouse. The Furnace 12 scrubber outlet PAH test

was conducted during FeMn production, and the Furnace 1 baghouse outlet and Furnace 1 tapping

baghouse outlet PAH tests were con ducted during SiMn production. The test samples were diluted

2000 times to obtain concentration results within the calibration. Because of the extreme dilution of

the samples

, the quantitative accuracy of the isotope dilution corrections to the data were b rought

into question. Furthermore, a valid emissions test generally should include 3 test runs. However,

as stated above, these July 2012 PAH emissions tests included only one run. Therefore, these July

2012 PAH test data were excluded from the dataset for PAH MACT Floor determinations.

4 Memorandum from Barrett Parker and Brian Shrager, EPA OAQPS to Docket ID No. EPA

- HQ

- OAR

- 2010

- 0895, Approach for Applying the Upper Prediction Limit to Limited Datasets, September 3, 2014. (This memo is also
referred to as the Limited Dataset Memo).3 

### Table 2

- 1 . Proposed HAP Emission Standards for the Ferroalloys Production NESHAP Subsequent to the Supplemental Proposal of October 10, 2014 (79 FR 60238)

HAP Pollutant New or

Reconstructed or Existing Source Affected Source Proposed

Emission

Standard

PM (surrogate for metal HAP) New or reconstructed Electric arc furnace (EAF) 9.3 mg/dscm

PM (surrogate for metal HAP) Existing EAF 24 mg/

Hg Existing EAF ( FeMn production ) 170 μg/dscm

Hg New or reconstructed EAF (FeMn production) 170 μg/dscm

Hg Existing EAF (SiMn production) 12 μg/dscm

Hg New or reconstructed EAF (SiMn production ) 4 μg/dscm

PAH Existing EAF (FeMn production) 1,400 μ g/dscm

PAH New or reconstructed EAF (FeMn production) 880 μ g/dscm

PAH Existing EAF (SiMn production) 120 μg/dscm

PAH New or reconstructed EAF (SiMn production) 72 μg/dscm

HCl Existing EAF 1,100 μg/dscm

HCl New or reconstructed EAF 180 μg/dscm

Formaldehyde New, reconstructed, or existing EAF 201 μg/dscm

PM (surrogate for metal HAP) New, reconstructed, or existing Local ventilation used to capture tapping, casting, or

ladle treatment emissions 24 mg/dscm

PM (surrogate for metal HAP) New, reconstructed, or existing MOR process 3.9 mg/dscm

PM (surrogate for metal HAP) New, reconstructed, or existing Crushing and screening operations 13 mg/dscm4 

### 4 .0 MACT F LOOR AND VARIABILITY ANALYSIS RESULTS

This section provides the results of the revised MACT floor analyses and UPL calulations for

existing and new sources for PAH and Hg

. Tables 4

- 1 through 4

- 4 present the results of the

existing source MACT floor and variability analyses for PAH and H g

. The procedures outlined in

the UPL caclulation memorandum 5 

### were used to determine the approriate UPL equation to use.

4 .1 Existing Furnace

- PAH

T he test data for the furnace total PAH concentrations during FeMn and SiMn production were

determined to be non

- normal based on the results of the skewness and kurtosis tests. Because the

amount of manganese ore, coal, and coke di ffers when producing the different products

, separate
statistical analys e s w ere performed on the PAH test data during FeMn and SiMn production. The

results of these analyses are provided in Table 4

- 1 and 4

- 2

.

The results of the PAH analysis show that there is a significant difference in PAH emissions during

FeMn production as compared to SiMn production. It was concluded that the difference of PAH

emissions during FeMn production and SiMn reduction was a result of the recipe and input

mater ials used to make the different products. Therefore, it was determined that it would be

appropriate to have two subcategories for PAH emissions and establish separate MACT limits for

each of these two subcategories. The UPL results for these data sets usi ng a 99 percent confidence

level were were rounded up to the next highest integer using 2 or 3 significant figures , therefore the

MACT floor limits for existing furnace sources were determined to be 1 1

, 5 00 μg/dscm for FeMn

production and 1 3 0 μg/dscm for SiMn production. At these levels, we expect neither source would

need to install additional controls to meet the emission limits.

4

. 2 New Furnace

- PAH

T here are only two furnaces in the source category that produce FeMn, and both furnaces are located at Eramet. The units are similar in design and process the same types of raw materials, and

we, therefore, expect little or no difference in the performance of these units. The available

emissions data, which show that the two units mean emiss ions are only 2 percent different, support

this hypothesis. We conclude, based on the similarities in the units and the available data that these

two furnaces achieve the same degree of control of PAH emissions with their current control

devices. According ly, we consider these two units to be equal performers with regard to PAH

emissions and we used all the data from both units to calculate the new source limit. Using the 99

percent UPL calculation, we derive an emissions limit of 11,500 ug/dscm for new fur naces producing ferromanganese.

5 Me morandum from Phil Mulrine, EPA OAQPS/SPPD/MICG to Docket ID No. EPA

- HQ

- OAR

- 2010

- 0895, Use of Upper Prediction Limit for Calculating MACT Floors, July 30, 2014. EPA

- HQ

- OAR

- 0895

- 0179.5 

### Table 4

- 1. Existing Source MACT Floor and Variability Analysis Results for Furnace PAH

during FeMn Production

PAH MACT Floor

- FeMn Furnace

Total Facility Count 1 # Facilities

Total Furnace Count 2 # Furnaces

Average

- All Runs 4482.04 μg/dscm

Minimum

- All Runs 244.100 μg/dscm

Maximum

- All Runs 10488.44 μg/dscm

Sample Size (n) 13 # of runs

Skewness (S) 0.25
Std Error of Skewness (SES) 0.68

Skewness Test (reported values) 0.36 S/SES

Normal S/SES>2

Kurtosis (K)

- 1.84
Std Error of Kurtosis (SEK) 1.36

Kurtosis Test (reported values) - 1.35 K/SEK

Normal K/SEK>2

99% UPL (normal distribution) 11458.21 μg/dscm



### Table 4

- 2. Existing Source MACT Floor and Variability Analysis Results for Furnace PAH

during SiMn Production

PAH MACT Floor

- SiMn Furnace

Total Facility Count 2 # Facilities

Total Furnace Count 5 # Furnaces

Average

- All Runs 74.84 μg/dscm

Minimum

- All Runs 21.230 μg/dscm

Maximum

- All Runs 158.53 μg/dscm

Sample Size (n) 22 # of runs

Skewness (S) 0.46
Std Error of Skewness (SES) 0.52

Skewness Test (reported values) 0.88 S/SES

Normal S/SES>2

Kurtosis (K) 0.09
Std Error of Kurtosis (SEK) 1.04

Kurtosis Test (reported values) 0.09 K/SEK

Normal K/SEK>2

99% UPL (normal distribution) 128.12 μg/dscm6 

### The analysis and calculations used to determine the MACT floor for PAHs from new furnaces

producing SiMn are unchanged from the October 2014 supplemental proposal. T he final MACT

floor is 72 μg /dscm for PAHs from new furnaces producing SiMn.

4

. 3 Existing Furnace

- Hg

The mercury test results for FeMn production were significantly different in comparison to the

mercury test results during SiMn production. This difference is a direct result of the amount of raw

materials and procedures used to produce the different products. The FeMn product consists of

approximately 78 percent Mn content with a carbon content ranging from 7.5 to 0. 5 percent carbon,

and is produced using Mn ore and high carbon coke. The formula used to produce FeMn requires a

much greater amount of Mn ore in comparison to the SiMn production, and the high carbon coke is

needed to reduce the manganese oxide (MnO 2 

### ) in the ore to produce the high Mn content in the

FeMn product. The SiMn product is approximately 65 percent manganese, and includes

approximately 16 percent silicon and 2 percent carbon. A different formulation of raw materials is

used to produce the SiMn product. The primary source of mercury emissions from the furnace

smelting process is the Mn ore used to produce the products. Because of the difference in the

amount of Mn ore that is needed for FeMn production, the mercury emissions from FeMn

production are significantly higher than the mercury emissions from SiMn production. Therefore,

the ferroalloy products (FeMn and SiMn) were subcategorized for determining mercury emissions

limits, and separate MACT limits were established for each of these two sub categories.

A total of fourteen mercury tests from the outlet of the control device from the furnace smelting

process were submitted to EPA from the Ferroalloy facilities. Two of the tests were measured

using EPA Method 29 and the other twelve were measured using EPA Method 30B. One of the

EPA Method 30B tests was invalidated (Felman Furnace 5 performed on 3/20/2013) because the

test runs did not meet the breathrough criteria and lack ed sufficient QA/QC to be used in the

MACT Floor calculations . In addition, eight of the individual Method 30B runs were also

invalidated because the paired sample agreement was greater than t he EPA Method 30B quality

assurance criteria that requires the paired samples to have a relative deviation of less than or equal

to 10 percent for s amples with a mercury concentration of greater than 1 microgram per dry

standard cubic meter (μg/dscm). Therefore, the data set used to calculate the UPL for the MACT

Floor consisted of a total of 13 tests (5 during FeMn production and 8 during SiMn produc tion) for

a total of 3 3 individual runs (15 runs during FeMn production and 1 8 runs during SiMn

production)

.

A statistical analysis was performed on the FeMn data seta and the SiMn data set and a summary of

the results is provided in Tables 4

- 3 and 4

- 4 . The skewness and kurtosis tests performed on each of

the data sets showed that both the FeMn Production and the SiMn Production data sets were

normally distributed. The UPL for normally distributed data was used to calculate the UPL for

each of the two data sets. As the results show, the FeMn Production UPL result of 13 0 μg/dscm

(rounded up to the nearest whole integer using 2 significant figures) provides a limit that is higher7 

### than any of the test data results (to account for variability in the data s et) and provides a limit that

can be achieved using the current control technology.

The mercury data set for SiMn production was also determined to normally distributed and the UPL

for the data set was calculated to be 1 2 μg/dscm (rounded up to the near est whole integer). The

UPL, as described above, accounts for variability in the test data set and was determined to be

achievable using the current control technology.

4

. 4 New Furnace

- Hg

The MACT floor for new sources was calculated by first determining the “best performing source”

for each of the FeMn and SiMn production data sets. This was done by ranking the sources by the

99 percent UPL of the test data for each furnace. The source w ith the lowest UPL by furnace

product (FeMn or SiMn) would be established as the “best performing source”, and the 99 percent

UPL would be the MACT floor limit for new sources. A summary of the test data and the UPL

rankings are provided in Appendix A.

The test data f or FeMn production included 9 test runs from a single furnace (Eramet Furnace 12)

that was identified as the "best performing source" based on average emissions, and the 99 percent

UPL was calculated to be 1 3 0 μg/dscm (rounded up to the near est whole integer using 2 significant

figures)

.

The analysis and calculations used to determine the MACT floor for Hg from new furnaces

producing SiMn are unchanged from the October 2014 supplemental proposal. Error! Bookmark not defined.



### The final MACT floor is 4 μg/dscm for Hg from new furnaces producing SiMn.

5.0 SUMMARY OF REVISED MACT FLOOR DETERMINATIONS

The revised MACT floor determinations for PAH and Hg based on the new test data received prior

to and after the publication of the 2014 supplemental proposed amendments to the national

emission standards for hazardous air pollutants (NESHAP) for the ferroa lloys production source

category, published in the Federal Register on October 10, 2014 (79 FR 60238) are summarized in

Table 5

- 1. The test data used for the analyses are provided in Appendix A.8 

### Table 4

- 3. Existing Source MACT Floor and Variability A nalysis Results for Furnace H g during FeMn Production

H g MACT Floor

- FeMn Furnace

Total Facility Count 1 # Facilities

Total Furnace Count 2 # Furnaces

Average

- All Runs 68.58 μg/dscm

Minimum

- All Runs 28.614 μg/dscm

Maximum

- All Runs 130.36 μg/dscm

Sample Size (n) 15 # of runs

Skewness (S) 0.42
Std Error of Skewness (SES) 0.63

Skewness Test (reported values) 0.66 S/SES

Normal S/SES>2

Kurtosis (K)

- 1.38
Std Error of Kurtosis (SEK) 1.26

Kurtosis Test (reported values) - 1.09 K/SEK

Normal K/SEK>2

99% UPL (normal distribution) 127.84 μg/dscm



### Table 4

- 4. Existing Source MACT Floor and Variability Analysis Results for Furnace H g during SiMn Production

H g MACT Floor

- SiMn Furnace

Total Facility Count 2 # Facilities

Total Furnace Count 5 # Furnaces

Average

- All Runs 4.42 μg/dscm

Minimum

- All Runs 0.347 μg/dscm

Maximum

- All Runs 11.87 μg/dscm

Sample Size (n) 18 # of runs

Skewness (S) 0.61
Std Error of Skewness (SES) 0.58

Skewness Test (reported values) 1.06 S/SES

Normal S/SES>2

Kurtosis (K)

- 1.52
Std Error of Kurtosis (SEK) 1.15

Kurtosis Test (reported values) - 1.32 K/SEK

Normal K/SEK>2

99% UPL (normal distribution) 11.61 μg/dscm9 

### Table 5

- 1. Summary of Revised MACT Flo or Determination for PAH and Hg

HAP Pollutant New or

Reconstructed or Existing Source Affected Source Revised MACT

Floor Limits

PAH Existing Electric arc furnace during FeMn production 11,500 μ g/dscm

PAH New or reconstructed Electric arc furnace during FeMn production 11,500 μ g/dscm

PAH Existing Electric arc furnace during SiMn production 130 μg/dscm

PAH New or reconstructed Electric arc furnace during SiMn production 72 μg/dscm

Hg Existing Electric arc furnace during FeMn production 13 0 μg/dscm

Hg New or reconstructed Electric arc furnace during FeMn production 1 3 0 μg/dscm

Hg Existing Electric arc furnace during SiMn production 1 2 μg/dscm

Hg New or reconstructed Electric arc furnace during SiMn production 4 μg/dscm10 

### 6 .0 BEYOND THE FLOOR

To evaluate opportunities for emissions reductions beyond those that would result from requiring

facilities to meet the MACT floor emissions limits, we typically identify control techniques that

have the ability to achieve an emissions limit more stringent than the MACT floor and evaluate

whether the standard should be more stringent based on consideration of the factors enumerated in

section 112 (d)(2) of the Act.

No beyond the floor options were selected for PAH, as detailed in Revised MACT Floor Analys is

for the Ferroalloys Production Source Category

. 3



### For new and reconstructed furnaces producing FeMn, it was determined to employ a beyond the

flo or approach based on 90 percent mercury reduction as set out in Mercury Control Options and

Impacts for the Ferroalloys Production Industry Error! Bookmark not defined. 

### ( fabric filters and the

installation of brominated carbon activated carbon injection ), with a resultant emission limit of 1 3

μg/dscm (rounded up to the nearest whole integer.)11 

### Appendix A

PAH and H g Data Sets used to Calculate UPL12 Furnace Hg Data

Facility Sample

Date Sample Location Test Method Furnace

Product Run 1

Conc

. (μg/dscm) Run 2

Conc

. (μg/dscm) Run 3

Conc

. (μg/dscm) Run 4

Conc

. (μg/dscm) Average

Conc

. (μg/dscm) Furnace

Average

Conc

. (μg/dscm) Number
of Test

Runs in

Furnace

Average Furnace

99% UPL

Eramet 3/4/2013 Furnace 1 Baghouse Outlet Method 30B FeMn 2 8

. 614 44.3 39 3 6

. 477

Eramet 10/16/2014 Furnace 1 Baghouse Outlet Method 30B FeMn 9 6

. 40 3 13 0

. 358 10 8

. 607 71

. 602 10 1

. 602 79

. 894 6 17 2

. 754

Eramet 8/16/2010 Furnace 12 Scrubber Outlet Method 29 FeMn 30.9 17 29.0 46 34.71 3 31.5 59

Eramet 7/25/2012 Furnace 12 Scrubber Outlet Method 30B FeMn 79. 865 11 7

. 865 10 6

. 733 101. 261

Eramet 10/23/2012 Furnace 12 Scrubber Outlet Method 30B FeMn 47. 050 39

. 321 64. 470 5 0

. 280 61. 033 9 125. 618

Eramet 7/24/2012 Furnace 1 Baghouse Outlet Method 30B SiMn 8. 826 1 1

. 867 10

. 34 7 10

. 347 2 72

. 804

Eramet 3/4/2013 Furnace 12 Scrubber Outlet Method 30B SiMn 2.23 1 2.23 1

Eramet 10/16/2014 Furnace 12 Scrubber Outlet Method 30B SiMn 10. 660 10. 637 9. 307 10.45 2 10.26 4 8

. 657 5 1 8

. 606

Felman 7/9/2010 Furnace 2 Baghouse Outlet Method 29 SiMn 0. 694 4. 949 4. 327 3. 323

Felman 8/ 13 /2012 Furnace 2 Baghouse Outlet Method 30B SiMn 0.6 79 0.783 0. 731

Felman 3 / 20 /201 3 Furnace 2 Baghouse Outlet Method 30B Si Mn 0.469 0.528 0.498 1.775 7 6.040

Felman 8 /9/201 2 Furnace 5 Baghouse Outlet Method 30B SiMn 0.629 0.629 0.629 1 N/A

Felman 8/7/2012 Furnace 7 Baghouse Outlet Method 30B SiMn 0.3 47 0.68 3 1.53 5 0.85 5 0.85 5 3 4.3 37 Furnace PAH Data

Facility Sample Date Sample Location Test Method Furnace

Product Run 1

Conc. (μg/dscm) Run 2

Conc. (μg/dscm) Run 3

Conc. (μg/dscm) Run 4

Conc. (μg/dscm) Average

Conc. (μg/dscm) Furnace

Average

Conc (μg/dscm) Number
of Test

Runs in

Furnace

Average Furnace

99% UPL

Eramet 3/6/2013 Furnace 1 Baghouse Outlet Method 429 FeMn 1141.2 646.9 732.2 840.1

Eramet 10/15/2014 Furnace 1 Baghouse Outlet Method 429 FeMn 6148.1 8939.9 9056.3 4405.5 7137.5 4438.6 7 12528.6

Eramet 8/17/2010 Furnace 12 Scrubber Outlet Method 23 FeMn 244.1 357.3 429.5 343.6

Eramet 10/23/2012 Furnace 12 Scrubber Outlet Method 429 FeMn 10488.4 9343.7 6333.3 8721.8 4532.7 6 15920.0

Eramet 3/6/2013 Furnace 12 Scrubber Outlet Method 429 SiMn 108.6 91.4 87.4 95.8

Eramet 10/16/2014 Furnace 12 Scrubber Outlet Method 429 SiMn 109.5 95.2 158.5 107.9 117.8 108.3 7 160.1

Felman 7/25/2012 Furnace 2 Baghouse Outlet Method 429 SiMn 27.8 25.2 21.2 24.7

Felman 3/18/2013 Furnace 2 Baghouse Outlet Method 429 SiMn 38.3 117.9 56.0 70.7 47.7 6 134.7

Felman 8/10/2012 Furnace 5 Baghouse Outlet Method 429 SiMn 58.2 57.4 59.9 58.5

Felman 3/14/2013 Furnace 5 Baghouse Outlet Method 429 SiMn 103.0 80.9 59.0 81.0 69.7 6 114.0

Felman 8/7/2012 Furnace 7 Baghouse Outlet Method 429 SiMn 62.9 59.2 61.2 61.1 61.1 3 71.7