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MEMORANDUM

TO: Rochelle Boyd, EPA

FROM: Mark Bahner, RTI

DATE: September 28, 2011

SUBJECT: Procedures Used to Calculate Allowable and Actual Dioxin/Furan (D/F)

Emissions for Secondary Aluminum Production Risk Modeling Files

The purpose of this memorandum is to document the procedures and rationale used to calculate 

allowable and actual D/F emissions (in toxic equivalents, or TEQ) for the Secondary Aluminum 

Production residual risk modeling files. Procedures are listed for sweat furnaces, Group I 

furnaces handling other than clean charge, scrap dryer/delacquering/decoating kilns, and chip 

dryers. These are the four types of secondary aluminum production equipment that have D/F 

emissions.

Sweat Furnaces

Allowable Emissions

1) Calculate volume of exhaust per ton of aluminum produced, based on four stack test 

reports. See Table 1 at the end of this memorandum for details. Value is approximately 

148,000 cubic feet of exhaust per ton of aluminum.

2) Calculate the conversion factor that converts one ton of aluminum produced to tons of 

dioxin (TEQ) produced, at the emission limit of the standard, using the exhaust volume 

per ton of aluminum calculated in Step 1. See Table 2 at the end of this memorandum for 

details.

3) Multiply production capacity by the conversion factor in Step 2.

4) Multiply the result by 0.5.

5) If production capacity is not available, use the average production capacity for all other 

sweat furnaces.
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Actual Emissions 

1) Multiply actual production by the conversion factor in Step 2 of allowable emissions.

2) Multiply the result by 0.35/0.8. This represents the fact that, during the D/F testing used 

to establish the standard, the average concentration for the three runs was 0.35 nanograms 

per dry standard cubic meter, whereas the standard was set at 0.8 nanograms per dry 

standard cubic meter.

Group I Furnaces Handling Other than Clean Charge

Allowable Emissions

1) Multiply production capacity (in megagrams/yr) by the emission limit of 15 micrograms 

per megagram of feed.

2) Multiply the result by 0.5.

Actual Emissions

1) Multiply the actual production by the actual emissions (in micrograms per megagram of 

feed) reported in the ICR.

2) If the actual production is not available, multiply the production capacity factor by the 

average capacity factor for all other Group I furnaces handling other than clean charge.

3) If the actual emissions (in micrograms per megagram of feed) are not available, use the 

average ratio of actual emissions to allowable emissions for all other Group I furnaces 

handling other than clean charge.

Scrap Dryer/Delacquering/Decoating Kilns

Allowable Emissions

1) Multiply production capacity (in megagrams/yr) by the emission limit of 5.0 micrograms 

per megagram of feed (which is the limit for a scrap dryer/delacquering/decoating kiln 

with an afterburner with a residence time of at least 1 second and operates at a 

temperature of at least 1400F).

2) Multiply the result by 0.5.

Actual Emissions
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1) Multiply the actual production by the actual emissions (in micrograms per megagram of 

feed) reported in the ICR.

2) If the actual production is not available, multiply the production by the average capacity 

factor for all other scrap dryer/delacquering/decoating kilns. 

3) If the actual emissions (in micrograms per megagram of feed) are not available, use the 

average ratio of actual emissions to allowable emissions for all other scrap 

dryer/delacquering/decoating kilns.

Chip Dryers

Allowable Emissions

1) Multiply production capacity (in megagrams/yr) by the emission limit of 2.5 micrograms 

per megagram of feed.

2) Multiply the result by 0.5.

Actual Emissions

1) Multiply the actual production by the actual emissions (in micrograms per megagram of 

feed) reported in the ICR.

2) If the actual production is not available, multiply the capacity by the average capacity 

factor for all other chip dryers.

3) If the actual emissions (in micrograms per megagram of feed) are not available, use the 

average ratio of actual emissions to allowable emissions for all other chip dryers.
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Table 1. Sweat Furnaces: Median Volume of Exhaust per Ton of Aluminum

RTI 

ID # Facililty Parameter Value Units

50 Dittmer's Recycling Average flow rate 1050 dscfm

Production during run 0.4295 tons

Run length 1 hour

Volume per ton 146,682 dcsf/ton

89 Pita Metals Average flow rate 2446 dscfm

Production during run 1.4565 tons

Run length 1 hour

Volume per ton 100,762 dcsf/ton

117 NH Kelman Average flow rate 6430 dscfm

Production during run 0.75 tons

Run length 1.06667 hour

Volume per ton 548,693 dcsf/ton

N/A Rochester Aluminum Smelting Corp. Average flow rate 1001 dscfm

Production during run 0.4 tons

Run length 1 hour

Volume per ton 150,150 dcsf/ton

Median 148,416 dscf/ton
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Table 2. Conversion Factor Calculation for Sweat Furnaces

Sweat furnace - D/F (limit = 0.8 Ng/dscm @ 11% O2)

1 ton aluminum 148,416 dscf 0.8 Ng 1 dscm 1 gram 1 pound 1 ton

1 ton aluminum 1 dscm 35.3 dscf 1,000,000,000 Ng 454 grams 2000 pounds

Conversion factor = 3.70E-12