### DATE: January 30 , 2012

**SUBJECT:** Draft Technical Support Document for the Secondary Aluminum Production Source Category **FROM:** Mark Bahner, RTI International **TO:** Rochelle Bo yd , U.S. Environmental Protection A gency (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, S ubpart 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 canop y hoods versus the furnace stacks, potentially

affects the results

. Inthe 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 presumabl y 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 canop y 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 canop y 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 b y the furnace stack, for all pollutants and for both tests, was 71 percent. The EPA has considered various potential furnace stack capture eff i encies 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 ta bles 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 canop y 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 canop y 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 canop y hood stack versus the total mass of pollutants emitted through both the canop y hood stack and the furnace stack. **2. Costs for**  **Lowering the Dioxin/Furan (D/F) limit for Group 1 Furnaces** The EPA multipathway

screen anal ys is 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 analys is focused on two options: 1) lower the D/F limit from 15 to 10 μ g 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 μ g TEQ/Mg , after appl ying a subcategorization that only required facilities producing more than 200,000 tpy in group 1 furnaces to meet the lower l imit. 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 responses 1 

### , it was estimated that approximately 11 facilities would ne ed 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 estimate d to need to red uce 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 c ost- effectiveness of approximately $1.22 million per gram D/F TEQ.

### 3

Our cost estimates were based on furnaces that were already controlled b y 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 s ys tems, 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 Jersey

2 

### , 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. Becaus e 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 probabl y much lower than emissions during normal operations since no scrap would be process ed. 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 simi lar 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 gradual ly 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 probabl y 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 te st 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 Te**  **sting** The EPA use d a nine

- company I CR to gather testing data that would correlate emissions of THC surrogate to speciated organic HAP s 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 b y 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.

### 5 

## 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, 20 07: 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

### 7

**Table 2**  **. Group 1 Furnace D/F Reduction Options**  **Opt ion**  **Furnace Status**  **Number of**

**Furnaces Capital Cost**  **1**

**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 .**  **Co st** **- 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 A**  **1. Southwire Testing Reported June 26, 2007: Complete Test Results**  **Southw ir**  **e Te**  **stin g R** 

**ep or** **ted on J**  **une 2**  **6, 2**  **007 PM**  **PM HCl**  **HCl TOTA** **L D /F**  ***** **TOTA L D**  **/F** ***** Durat ion(hr) fu rn ace 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

Durat ion(hr) canopy h ood 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

To ta l 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 av erage 6. 27 lb 6. 71 lb 4. 97E-07 lb * reported as 2378
- TCDD equivalent

### 10

**Table A** **2. Southwire Testing**  **Reported on June 26, 2007: Results in Pounds Southw**  **ir e**  **Te sti**  **ng Re por** **ted on J**  **une 2**  **6, 2**  **007**
**Pollut an**  **t Loc**  **at ion**  **Un it** **s Run 1**  **Ru n 2**  **Ru n 3**  **Ave rag**  **e** PM Fu rnace stack lb 4. 31 6. 00 4. 39 4. 90 PM Canopy h ood lb 0. 96 1. 93 1. 23 1. 37

PM To ta l lb 5. 27 7. 93 5. 62 6. 27
PM Fu rnace stack fra cti on of to ta l 0. 82 0. 76 0. 78 0. 78 PM Canopy h ood fra cti on of to ta l 0. 18 0. 24 0. 22 0. 22 22% Avg PM To ta l fra cti on of to ta l 1. 00 1. 00 1. 00 1. 00
HCl Fu rnace stack lb 5. 47 5. 60 5. 31 5. 46 HCl Canopy h ood lb 1. 53 1. 37 0. 84 1. 25 HCl To ta l lb 7. 00 6. 97 6. 15 6. 71
HCl Fu rnace stack fra cti on of to ta l 0. 78 0. 80 0. 86 0. 81 HCl Canopy h ood fra cti on of to ta l 0. 22 0. 20 0. 14 0. 19 19% Avg

HCl To ta l fra cti on of to ta l 1. 00 1. 00 1. 00 1. 00
To ta l D/ F Fu rnace stack lb 6. 69E- 07 6. 18E -07 1. 68E -07 6. 35E -07 To ta l D/ F Canopy h ood lb 1. 16E- 08 1. 64E -08 8. 85E -09 1. 48E -08 To ta l D/ F To ta l lb 6. 81E- 07 6. 34E -07 1. 77E -07 4. 97E -07
To ta l D/ F Fu rnace stack fra cti on of to ta l 0. 98 0. 97 0. 95 0. 97 To ta l D/ F Canopy h ood fra cti on of to ta l 0. 02 0. 03 0. 05 0. 03 3% Avg To ta l D/ F To ta l fra cti on of to ta l 1. 00 1. 00 1. 00 1. 00

### 11

**Table A** **3 .**  **Southwire Testing Reported September 5, 2007**  **: Complete Test Results So**  **uthw ir**  **e Te**  **st ing Re**  **por ted** **on Se pt**  **emb er**  **5, 2**  **007 PM**  **PM HCl**  **HCl TOTA** **L D/F** ***** **TOTAL D /F**  ***** Durat ion(hr) fu rnace stack Run 1 3. 20 0. 61 #/ hr 1. 95 lb 1. 38 #/hr 4. 42 lb 2. 02E -09 #/ hr 6. 46E -0 9 lb Run 2 3. 20 0. 49 1. 57 lb 0. 81 2. 59 lb 3. 97E -09 #/ hr 1. 27E -0 8 lb Run 3 3. 20 0. 49 1. 57 lb 0. 68 2. 18 lb 8. 31E -10 #/ hr 2. 66E -0 9 lb

Durat ion(hr) ca nopy h ood Run 1 3. 00 0. 86 #/ hr 2. 58 lb 0. 38 #/hr 1. 14 lb 8. 31E -09 #/ hr 2. 49E -0 8 lb Run 2 3. 00 0. 36 1. 08 lb 0. 25 0. 75 lb 2. 20E -09 #/ hr 6. 60E -0 9 lb Run 3 3. 00 0. 53 1. 59 lb 0. 28 0. 84 lb 1. 35E -09 #/ hr 4. 05E -0 9 lb

To ta l Run 1 4. 53 lb 5. 56 lb 3. 14E -0 8 lb Run 2 2. 65 lb 3. 34 lb 1. 93E -0 8 lb Run 3 3. 16 lb 3. 02 lb 6. 71E -0 9 lb av erage 3. 45 lb 3. 97 lb 1. 91E -0 8 lb

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**Table A** **4 .**  **Southwire Testing Reported on September 5**  **, 2007: Results in Pounds** Southw ire Testing Reporte d on Se ptem ber 5 , 2007 **Po llutant**  **Lo ca** **tio n**  **Units Run**  **1 Run**  **2 Ru** **n 3 Av**  **er ag**  **e** PM Fur na ce stack lb 1. 95 1. 57 1. 57 1. 70 PM Canopy hood lb 2. 58 1. 08 1. 59 1. 75

PM Tota l lb 4. 53 2. 65 3. 16 3. 45 PM Fur na ce stack fracti on of tota l 0. 43 0. 59 0. 50 0. 49 PM Canopy hood fracti on of tota l 0. 57 0. 41 0. 50 0. 51 51% Avg PM Tota l fracti on of tota l 1. 00 1. 00 1. 00 1. 00 HCl Fur na ce stack lb 4. 42 2. 59 2. 18 3. 06 HCl Canopy hood lb 1. 14 0. 75 0. 84 0. 91 HCl Tota l lb 5. 56 3. 34 3. 02 3. 97 HCl Fur na ce stack fracti on of tota l 0. 79 0. 78 0. 72 0. 77 HCl Canopy hood fracti on of tota l 0. 21 0. 22 0. 28 0. 23 23% Avg
HCl Tota l fracti on of tota l 1. 00 1. 00 1. 00 1. 00 Tota l D/F Fur na ce stack lb 6. 46E -09 1. 27E-08 2. 66E-09 1. 06E -0 8 Tota l D/F Canopy hood lb 2. 49E -0 8 6. 60E-09 4. 05E-09 1. 27E -0 8 Tota l D/F Tota l lb 3. 14E -0 8 1. 93E-08 6. 71E-09 1. 91E -0 8 Tota l D/F Fur na ce stack fracti on of tota l 0. 21 0. 66 0. 40 0. 42 Tota l D/F Canopy hood fracti on of tota l 0. 79 0. 34 0. 60 0. 58 58% Avg Tota l D/F Tota l fracti on of tota l 1. 00 1. 00 1. 00 1. 00