DATE: January 30, 2012

SUBJECT: Draft Technical Support Document for the Secondary Aluminum Production Source 

Category

FROM: Mark Bahner, RTI International

TO: Rochelle Boyd, U.S. Environmental Protection Agency (the EPA)

The purpose of this memorandum is to document the technical approach and rationale used to develop 

certain proposed modifications to the National Emission Standards for Hazardous Air Pollutants 

(NESHAP) for Secondary Aluminum Production (40 CFR Part 63, Subpart RRR). The modifications are 

to be proposed in January 2012.

1. Capture Efficiency Assumption for Uncontrolled Furnaces

Test data related to the capture efficiency for uncontrolled furnaces were analyzed. Two tests were 

available. Both were conducted at Southwire Corporation in Hawesville, KY. Testing was also 

conducted on an in-line fluxer, but those results were not included in the analysis. Testing was 

performed for PM, HCl and PCDD/PCDF from April 30 – May 02, 2007 at Furnace #5 in Mill 3, as 

reported on June 26, 2007. Testing was performed for PM, HCl and PCDD/PCDF from July 17 – 19, 

2007 at a Group 1 furnace located in Rod Mill 1 and reported on September 5, 2007. Testing was 

performed on a furnace stack and also on a temporary canopy hood, which was installed for the test, to 

capture emissions not directed through the furnace stack.

One aspect of this testing, regarding sampling time at the canopy hoods versus the furnace stacks,

potentially affects the results. In the testing reported on June 26, 2007, sampling at the furnace stack was 

performed from 7.7 to 8 hours per run, whereas sampling at the canopy hood was performed for 3.0 to 

3.33 hours per run. This is consistent with the concept that emissions captured by the canopy hood 

would only occur during furnace charging, whereas emissions through the furnace stack would occur 

throughout the cycle (charging, melting, tapping) which presumably lasted 7.7 to 8.0 hours. However, in 

the testing reported on September 5, 2007, testing at the furnace stack was performed for 3.2 hours per 

run, whereas testing at the canopy hood was performed for 3.0 hours per run. This could mean that the 

complete furnace cycle was only 0.2 hours longer than the charging period, or it could be a mistake in 

the testing reported on September 5, 2007, such that the testing at the furnace stack did not occur 

throughout the entire furnace cycle. If the testing reported on September 5th was indeed flawed in that 

the sampling at the furnace stack did not occur throughout the furnace cycle, then the ratio of emissions 

in the canopy hood stack to total emissions would be biased high. 

The results of the two tests are summarized in Table 1. From Table 1, it can be seen that the average 

capture by the furnace stack, for all pollutants and for both tests, was 71 percent. The EPA has 

considered various potential furnace stack capture effiencies and resultant stack test estimation factors 

for uncontrolled furnaces. For example, if the furnace capture efficiency is assumed to be 50 percent, the 

furnace test results would need to be multiplied by a factor of 2. If the furnace capture efficiency was 
2

assumed to be 66.67 percent (approximately 67 percent), the furnace test results would need to be 

multiplied by a factor of 1.5. The test results in Table 1 support multiplying the furnace test results by a 

factor of 1.5, because the average capture efficiency for all tests was 71 percent, which is slightly higher 

than 67 percent.

Additional tables related to this analysis are included in Appendix A to this memorandum. The tables 

can be summarized as follows:

Table A1: This table presents data from the June 26, 2007 report. The data included 

pollutant emissions in pounds per hour and test sampling time. These are converted into 

total mass measured, so that the total emissions from the furnace stack can be compared 

to the total emissions in the canopy hood stack.

Table A2: This table presents data from the June 26, 2007 report. The data are 

exclusively in pounds and the table includes a calculation of the percentage of polluetants 

emitted through the canopy hood stack versus the total mass of pollutants emitted through 

both the canopy hood stack and the furnace stack.

Table A3: This table presents data from the September 5, 2007 report. The data included 

pollutant emissions in pounds per hour and test sampling time. These are converted into total 

mass measured, so that the total emissions from the furnace stack can be compared to the total 

emissions in the canopy hood stack.

Table A4: This table presents data from the September 5, 2007 report. The data are exclusively

in pounds and the table includes a calculation of the percentage of polluetants emitted through 

the canopy hood stack versus the total mass of pollutants emitted through both the canopy hood 

stack and the furnace stack.

2. Costs for Lowering the Dioxin/Furan (D/F) limit for Group 1 Furnaces

The EPA multipathway screen analysis results indicated exceedances of worst-case screening levels, 

which do not necessarily indicate risks; however, they cannot be ruled out based on the results. 

To evaluate the potential to reduce D/F emissions, our analysis focused on two options: 1) lower the D/F 

limit from 15 to 10 μg TEQ/Mg (micrograms toxic equivalent per Megagram of feed) for group 1 

furnaces processing other than clean charge at all facilities, and 2) lower the D/F limit for Group 1 

furnaces processing other than clean charge to 10 μg TEQ/Mg , after applying a subcategorization that 

only required facilities producing more than 200,000 tpy in group 1 furnaces to meet the lower limit.

These lower limits could potentially be met with activated carbon injection systems. 

With regard to the first option, based on testing reported in information collection request responses1, it 

was estimated that approximately 11 facilities would need to reduce their D/F emissions, and that the 

costs would be approximately $5.9 million in total capital costs, with total annualized costs of 

approximately $2.7 million. This option was estimated to achieve an approximately 1.66 grams TEQ 

reduction of D/F, with an overall cost-effectiveness of approximately $1.61 million per gram D/F TEQ.

For the second option, again based on testing and production data reported in information collection 

responses, approximately 4 facilities were estimated to need to reduce their D/F emissions, and that the 

costs would be approximately $129,000 in total capital costs, with total annualized costs of 

approximately $464,000. This option is estimated to achieve an aproximately 0.38 grams TEQ reduction 

of D/F with an overall cost-effectiveness of approximately $1.22 million per gram D/F TEQ.
3

Our cost estimates were based on furnaces that were already controlled by fabric filters simply adding an 

activated carbon injection system, which is relatively low in capital cost, but is high in operating costs, 

due to the cost of activated carbon. Our cost estimates for uncontrolled furnaces were based on adding 

fabric filters and activated carbon injection systems, which have high capital costs as well as operating 

costs. All costs were based on a study done for the costs of adding fabric filters and activated carbon 

injection done for a utility in New Jersey2, with costs adjusted for the lower flow rate for secondary

aluminum furnaces (assumed to be 45,000 acfm, based on ICR responses).

3. Compliance with Emission Limits during Startup/Shutdown

The EPA is proposing standards for startup and shutdown for all secondary aluminum process units. The 

subpart RRR standards would apply at all times, including periods of startup and shutdown. Because the 

scrap processed at secondary aluminum production facilities is the source of emissions, emissions during 

startup and shutdown are expected to be no higher and probably much lower than emissions during 

normal operations since no scrap would be processed. Therefore, the agency sees no reason why the 

existing standards should not apply at all times. 

For production processes in the secondary aluminum production source category where the standards are 

expressed in units of pounds per ton of feed or similar units (i.e. thermal chip dyers, scrap 

dryer/delacquering kiln/decoating kilns, dross-only furnaces, in-line fluxers using reactive flux and 

group 1 furnaces), the form of the standard would raise implementation issues if facilities were simply

required facilities to demonstrate compliance in the exact same way as they do during normal operations 

, because the equipment is not receiving feed material during startup and shutdown periods. For 

example, the startup procedure for a furnace consists of gradually heating the furnace to normal 

operating temperature, without any addition of feed material. Since the feed rate is zero, the emission 

rate per ton of feed would be calculated to be infinite.

One possibility would be to have concentration-based limits. However, these are probably not 

appropriate for the secondary aluminum industry, because hooding draws in large amounts of ambient 

air in order to increase hooding capture. Therefore, it is expected that emissions during startup and 

shutdown will be measured and determined under the applicable test method in pounds per hour 

(lb/hr).Under the proposed rule, to demonstrate compliance during the startup and shutdown periods, for 

the emissions standards that are in units of lbs per ton, the emissions in units of pounds per hour would

be divided by the feed rate in tons per hour (ton/hr) from the most recent or current performance test and 

compared to the emission limit for the affected source. For example, the PM limit for a new or existing 

group 1 furnace is 0.4 lb/ton. If, during a startup or shutdown, the emission rate determined under the 

applicable test method is 2 lb/hr, and the furnace charge rate during the most recent performance test 

was 10 tons per hour, the calculated emission rate for that test during a period of startup or shutdown 

would be 0.2 lb/ton of feed (2 lb/hr of PM divided by 10 tons per hour of feed). This would be in 

compliance with the PM standard of 0.4 lb/ton of feed.

4. Representativeness for Nine-Company HAP Metals and HAP Organics Testing

The EPA used a nine-company ICR to gather testing data that would correlate emissions of THC

surrogate to speciated organic HAPs and emissions of PM surrogate to speciated metal HAPs. Testing 

was limited to nine companies for efficiency and to avoid undue burden to the industry. The nine 

companies were chosen primarily because they were large companies operating many facilities, and 

because they were companies that were known to operate major source facilities that had thermal chip 

dryers or scrap dryer/delacquering/decoating kilns. Thermal chip dryers and scrap dryer/delacquering 
4

decoating kilns are the only types of equipment that have THC limits. These two pieces of equipment

were limiting in selecting companies for testing, in that few companies in the secondary aluminum 

source category currently operate those pieces of equipment. Therefore, the sampling for those pieces of 

equipment was representative, because the sampling represented a large fraction of those pieces of 

equipment operated by the industry. The sampling for HAP metals in fabric filter dust represented a 

much smaller fraction of the industry (less than 10 percent of all pieces of equipment). However, there 

were a total of 55 samples analyzed for the full suite of HAP metals (including arsenic, cadmium, total 

chromium and hexavalent chromium, manganese, mercury, nickel, etc.). Because 55 samples were taken 

from many facilities owned by nine companies, these results are believed to be representative of metal 

concentrations in fabric filter dust within the secondary aluminum industry and are suitable for use in 

developing speciated metal HAP emissions from PM emissions. 

References

1. Letter, Peter Tsirigotis (U.S. EPA) to Russell Mayfield (Mayfield Salvage Company) et al.,

“Requirement to provide information according to 42 U.S.C 7414,” February 7, 2011. This was 

the cover letter for the all-company data collection ICR.

2. Memorandum, Serpil Guran (New Jersey Department of Environmental Protection) to William 

O’Sullivan (New Jersey Department of Environmental Protection). Subject: Analysis for Coal 

Burning Boilers Mercury Emissions Levels and Control Options. May 8, 2003.
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List of Tables

Table 1. Southwire Test Results Summary............................................................................................. 6

Table 2. Group 1 Furnace D/F Reduction Options................................................................................. 7

Table 3. Cost-effectiveness Calculation for D/F Reduction Options ..................................................... 7

Table A1. Southwire Testing Reported June 26, 2007: Complete Test Results........................................ 9

Table A2. Southwire Testing Reported on June 26, 2007: Results in Pounds ........................................ 10

Table A3. Southwire Testing Reported September 5, 2007: Complete Test Results.............................. 11

Table A4. Southwire Testing Reported on September 5, 2007: Results in Pounds................................. 12
6

Table 1. Southwire Test Results Summary

Test Report Date Pollutant

Three-run Average

Fraction in Furnace Stack

Three-run Average

Fraction in Canopy Hood Stack

June 26, 2007 PM 0.78 0.22

June 26, 2007 HCl 0.81 0.19

June 26, 2007 D/F 0.97 0.03

Sept. 5, 2007 PM 0.49 0.51

Sept. 5, 2007 HCl 0.77 0.23

Sept. 5, 2007 D/F 0.42 0.58

Average for all All 0.71 0.29
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Table 2. Group 1 Furnace D/F Reduction Options

Option

Furnace 

Status

Number of 

Furnaces

Capital Cost1

Each (2011 $)

Annual Operating 

Cost Each

(2011 $)

Combined Total Capital 

Cost (2011$)

Combined Total 

Annualized Cost (2011$)

Limit of 10 μg/Mg TEQ for all Controlled 11 32,478 115,983

5,910,258 2,680,713

Limit of 10 μg/Mg TEQ for all Uncontrolled 9 617,000 156,100

Limit of 10 μg/Mg TEQ if 

production >200,000 tpy Controlled 4 32,478 115,983

129,912 463,932

Limit of 10 μg/Mg TEQ if 

production >200,000 tpy Uncontrolled 0 617,000 156,100

Table 3. Cost-effectiveness Calculation for D/F Reduction Options

Option

Combined Total 

Annualized Cost (2011$)

Annual D/F Emission Reduction 

(grams TEQ)

D/F Removal Cost Effectiveness

($/gram TEQ)

Limit of 10 μg/Mg TEQ for all 2,680,713 1.66 1,610,000

Limit of 10 μg/Mg TEQ if 

production >200,000 tpy 463,932 0.38 1,220,000
8

Appendix A

Southwire Test Results
9

Table A1. Southwire Testing Reported June 26, 2007: Complete Test Results 

Southwire Testing Reported on June 26, 2007

PM PM HCl HCl TOTAL D/F* TOTAL D/F*

Duration(hr) furnace stack

Run 1 7.70 0.56 #/hr 4.31 lb 0.71 #/hr 5.47 lb 8.69E-08 #/hr 6.69E-07 lb

Run 2 8.00 0.75 6.00 lb 0.7 5.60 lb 7.72E-08 #/hr 6.18E-07 lb

Run 3 7.70 0.57 4.39 lb 0.69 5.31 lb 2.18E-08 #/hr 1.68E-07 lb

Duration(hr) canopy hood

Run 1 3.00 0.32 #/hr 0.96 lb 0.51 #/hr 1.53 lb 3.87E-09 #/hr 1.16E-08 lb

Run 2 3.33 0.58 1.93 lb 0.41 1.37 lb 4.92E-09 #/hr 1.64E-08 lb

Run 3 3.00 0.41 1.23 lb 0.28 0.84 lb 2.95E-09 #/hr 8.85E-09 lb

Total

Run 1 5.27 lb 7.00 lb 6.81E-07 lb

Run 2 7.93 lb 6.97 lb 6.34E-07 lb

Run 3 5.62 lb 6.15 lb 1.77E-07 lb

average 6.27 lb 6.71 lb 4.97E-07 lb

* reported as 2378-TCDD equivalent
10

Table A2. Southwire Testing Reported on June 26, 2007: Results in Pounds

Southwire Testing Reported on June 26, 2007

Pollutant Location Units Run 1 Run 2 Run 3 Average

PM Furnace stack lb 4.31 6.00 4.39 4.90

PM Canopy hood lb 0.96 1.93 1.23 1.37

PM Total lb 5.27 7.93 5.62 6.27

PM Furnace stack fraction of total 0.82 0.76 0.78 0.78

PM Canopy hood fraction of total 0.18 0.24 0.22 0.22 22% Avg

PM Total fraction of total 1.00 1.00 1.00 1.00

HCl Furnace stack lb 5.47 5.60 5.31 5.46

HCl Canopy hood lb 1.53 1.37 0.84 1.25

HCl Total lb 7.00 6.97 6.15 6.71

HCl Furnace stack fraction of total 0.78 0.80 0.86 0.81

HCl Canopy hood fraction of total 0.22 0.20 0.14 0.19 19% Avg

HCl Total fraction of total 1.00 1.00 1.00 1.00

Total D/F Furnace stack lb 6.69E-07 6.18E-07 1.68E-07 6.35E-07

Total D/F Canopy hood lb 1.16E-08 1.64E-08 8.85E-09 1.48E-08

Total D/F Total lb 6.81E-07 6.34E-07 1.77E-07 4.97E-07

Total D/F Furnace stack fraction of total 0.98 0.97 0.95 0.97

Total D/F Canopy hood fraction of total 0.02 0.03 0.05 0.03 3% Avg

Total D/F Total fraction of total 1.00 1.00 1.00 1.00
11

Table A3. Southwire Testing Reported September 5, 2007: Complete Test Results

Southwire Testing Reported on September 5, 2007

PM PM HCl HCl TOTAL D/F* TOTAL D/F*

Duration(hr) furnace stack

Run 1 3.20 0.61 #/hr 1.95 lb 1.38 #/hr 4.42 lb 2.02E-09 #/hr 6.46E-09 lb

Run 2 3.20 0.49 1.57 lb 0.81 2.59 lb 3.97E-09 #/hr 1.27E-08 lb

Run 3 3.20 0.49 1.57 lb 0.68 2.18 lb 8.31E-10 #/hr 2.66E-09 lb

Duration(hr) canopy hood

Run 1 3.00 0.86 #/hr 2.58 lb 0.38 #/hr 1.14 lb 8.31E-09 #/hr 2.49E-08 lb

Run 2 3.00 0.36 1.08 lb 0.25 0.75 lb 2.20E-09 #/hr 6.60E-09 lb

Run 3 3.00 0.53 1.59 lb 0.28 0.84 lb 1.35E-09 #/hr 4.05E-09 lb

Total

Run 1 4.53 lb 5.56 lb 3.14E-08 lb

Run 2 2.65 lb 3.34 lb 1.93E-08 lb

Run 3 3.16 lb 3.02 lb 6.71E-09 lb

average 3.45 lb 3.97 lb 1.91E-08 lb
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Table A4. Southwire Testing Reported on September 5, 2007: Results in Pounds

Southwire Testing Reported on September 5, 2007

Pollutant Location Units Run 1 Run 2 Run 3 Average

PM Furnace stack lb 1.95 1.57 1.57 1.70

PM Canopy hood lb 2.58 1.08 1.59 1.75

PM Total lb 4.53 2.65 3.16 3.45

PM Furnace stack fraction of total 0.43 0.59 0.50 0.49

PM Canopy hood fraction of total 0.57 0.41 0.50 0.51 51% Avg

PM Total fraction of total 1.00 1.00 1.00 1.00

HCl Furnace stack lb 4.42 2.59 2.18 3.06

HCl Canopy hood lb 1.14 0.75 0.84 0.91

HCl Total lb 5.56 3.34 3.02 3.97

HCl Furnace stack fraction of total 0.79 0.78 0.72 0.77

HCl Canopy hood fraction of total 0.21 0.22 0.28 0.23 23% Avg

HCl Total fraction of total 1.00 1.00 1.00 1.00

Total D/F Furnace stack lb 6.46E-09 1.27E-08 2.66E-09 1.06E-08

Total D/F Canopy hood lb 2.49E-08 6.60E-09 4.05E-09 1.27E-08

Total D/F Total lb 3.14E-08 1.93E-08 6.71E-09 1.91E-08

Total D/F Furnace stack fraction of total 0.21 0.66 0.40 0.42

Total D/F Canopy hood fraction of total 0.79 0.34 0.60 0.58 58% Avg

Total D/F Total fraction of total 1.00 1.00 1.00 1.00