# DRAFT

Date: July 16, 2010

Subject: Emissions Reductions and Cost Effectiveness of HEPA Filter Retrofits for Chromium Electroplating Emission Standards Technical Suppor t and Post Promulgation Activities EPA Contract No. EP-D-06-118; EPA Work Assignment No. 4-6 RTI Project No. 0210426.004.006

From: James Cunningham
Richard Marinshaw

To: Phil Mulrine, EPA/OAQPS/SPPD/MMG

The purpose of this memorandum is to presen t the estimated emissions reductions, costs, and cost effectiveness of retrofitting high efficien cy particulate air (HEPA) filters on all existing sources subject to the National Emission Standa rds for Chromium Emissions from Hard and Decorative Chromium Electroplating a nd Chromium Anodizing Tanks (Chromium Electroplating NESHAP, 40 CFR 63, subpart N). Re trofitting HEPA filters is being considered as one regulatory option for reducing the risk associated with chromium emissions from chromium electroplating and anodizing.

Section I of this memorandum presents estimated baseline emissions of chromium compounds from existing electroplat ing and anodizing tanks subjec t to the NESHAP. Emissions reductions associated with retrofitting HEPA filte rs on all existing affected sources are presented in Section II. Section III describes the basis for, and results of, the cost estimates for HEPA filter retrofits nationwide, and the resulting cost-effectiveness is summarized in Section IV. References are provided in Section V.

I. Baseline Emissions for Chromium Electroplating and Anodizing Sources

The basic methodology used to estimate baseline emissions from chromium electroplating and anodizing sources was as follows:

1. Estimate the number of plants of each type (hard chromium electroplating, decorative chromium electroplating, and chromium anodizing);
2. For each type of plant, estimate the numb er of each size (small, medium, large);
3. Estimate uncontrolled emissions from each plant type and size;
4. Estimate control method distribution a nd apply control efficiencies; and
5. Sum up the controlled emissions nationwide.2

Estimated Number of Plants by Type

Table 1 summarizes the estimated number of chromium electroplating and anodizing plants nationwide. The basis for thes e estimates is provided in Reference 1.

Table 1. Estimated Number of Chromium Electroplating Plants a

Process Estimated No. of plants Hard chromium electroplating 790 Decorative chromium electroplating 740 Chromium anodizing 240
Total 1,770

a Reference 1.

Estimated Number of Plants by Size

The numbers of chromium electroplating a nd anodizing plants by size were estimated using the model plants and plant distributions developed for the NESHAP and documented in Chromium Emissions from Chro mium Electroplating and Chromic Acid Anodizing Operations -- Background Information for Proposed Standards (Reference 2). Three sizes of model plants (small, medium, and large) were developed for hard and decorative chro mium electroplating, and two sizes of model plants (small and large) we re developed for chromium anodizing. Table 2 summarizes the resulting nationwide brea kdown of plants by type and size.

Table 2. Distribution of Mode l Plants by Size and Type a

Electroplating Type Size % of total No. of plants
nationwide
Small 70% 553
Medium 20% 158 Large 10% 79 Hard Chromium

Total 790
Small 80% 592
Medium 15% 111 Large 5% 37 Decorative Chromium

Total 740
Small 75% 180 Large 25% 60 Chromium Anodizing
Total 240 Total, all plants 1,770

a Reference 2.3

Uncontrolled Emissions from Model Plants

The uncontrolled model plant emissions developed for the NESHAP were used in the determination of baseline chromium compound emi ssions. Table 3 summarizes these emissions.

Table 3. Uncontrolled Chromium Co mpound Emissions from Model Plants a

Electroplating Type Size Uncontrolled Cr emissions, lbs/yr
Small 110
Medium 926 Hard Chromium Large 3,530
Small 13
Medium 53 Decorative Chromium Large 530
Small 7.2 Chromium Anodizing Large 88

a Reference 2.

Control Efficiencies and Control Method Distribution

To determine controlled (baseline) emissions nationwide, assumptions were made about the numbers and types of emission control technol ogies in use, and the control levels (control efficiencies) achieved by those technologies. Fo r hard chromium electroplating tanks, the most commonly used controls are the composite mesh pad (CMP), p acked bed scrubber (PBS), and mesh pad mist eliminator (MPME). In additi on, as the result of the 2005 amendments to the NESHAP, some hard chromium electroplating ta nks are controlled using only a wetting agent fume suppressant (WAFS). To estimate the impacts of the original NESHAP, the assumed
control efficiencies for these devices were 99.5 percent for CMP and 99.0 percent for PBS and MPME. For WAFS, a control efficiency of 99.5 percent was used. Fo r decorative chromium electroplating tanks and chromium anodizing tanks, the contro ls used include PBS, MPME, and CMP, but most tanks are controlle d using WAFS. The same contro l efficiencies indicated above for hard chromium electroplating also appl y to decorative chromium electroplating and chromium anodizing. A summary of the control efficiencies used is presented in Table 4.

Table 4. Efficiencies of Chromium Electroplating Emission Controls a

Control Method Efficiency, % Composite mesh pad (CMP) 99.5 Packed bed scrubber (PBS) 99.0 Mesh pad mist eliminator (MPME) 99.0 Wetting agent fume suppressant (WAFS) 99.5

a Reference 2.

The distribution of emissi on control methods among the various types of chromium electroplating plants and plant sizes was estimated based on gene ral knowledge of the industry. Large hard chromium electroplating plants gene rally are controlled with CMPs; some PBSs are4

also used. For medium and small hard chromium electroplating plants, PBSs are more common. Some medium and small plants also use WAFS to control emissi ons. As noted above, WAFS is the most commonly used control method for deco rative chromium electroplating and chromium anodizing plants. However, other controls (P BS, MPME) also are used. To estimate the distribution, the percentage of pl ants that use WAFS was first assumed; then the percentages of each type of add-on control devices were estimate d. Since the control efficiencies for PBS and MPME are comparable, no distin ctions were made between th e two with respect to their
distribution. Table 5 summarizes the assumed di stribution of these controls among the various types of model plants. The resulting numbers of plants are summarized in Table 6.

Table 5. Distribution of Emission Co ntrols by Size and Type of Plant

% of Total Electroplating Type Model
Plant Size CMP PBS/MPME WAFS

Small 16 64 20
Medium 54 36 10 Hard Chromium Large 90 10 0
Small 0 10 90
Medium 2 18 80 Decorative Chromium Large 8 32 60
Small 0 10 90 Chromium Anodizing Large 8 32 60

Table 6. Distribution of Model Pl ants by Emission Control Method

Number of Plants Nationwide Electroplating Type Model
Plant Size CMP PBS/MPME WAFS Total

Small 88 354 111 553
Medium 85 57 16 158 Large 71 8 0 79 Hard Chromium

Total 790
Small 0 59 533 592
Medium 2 20 89 111 Large 3 12 22 37 Decorative Chromium

Total 740
Small 0 18 162 180 Large 5 19 36 60 Chromium Anodizing
Total 240

Estimated Controlled Baseline Emissions

Using the data and distributions discussed above and summarized in Tables 1 through 6,
nationwide baseline emissions of chromium compounds were estimated to be 3,279 pounds per year (lbs/yr) (1.64 tons per year [tons/yr]). Th is total is comprised of 3,030 lbs/yr for hard5

chromium electroplating, 207 lbs/yr for decora tive chromium electroplat ing, and 42 lbs/yr for chromium anodizing. Table 7 summarizes the results by model plant type and size.

Table 7. Estimated Baseline Emissions of Chromium Compounds

Electroplating Type Model Plant Size Nationwide Emissions, lbs/yr
Small 499
Medium 995 Large 1,536 Hard Chromium

Total 3,030
Small 42
Medium 35 Large 130 Decorative Chromium

Total 207
Small 7 Large 35 Chromium Anodizing
Total 42 Nationwide total 3,279

II. Estimated Emissions Reductions for HEPA Filter Retrofit

To estimate the emissions reductions that woul d be achieved by retrofitting HEPA filters on all existing sources subject to the Chromium Electroplating NESHAP, the control efficiency of HEPA filters was first applie d to uncontrolled baseline emissi ons. By definition, HEPA filters are designed to remove at least 99.97 percent of ai rborne particles that are 0.3 micrometers (μm) or larger in diameter. The onl y available particle size data for uncontrolled emissions from chromium electroplating sources, as summarized in Table 8, indicates that chromic acid mist emitted from hard chromium electroplating is comprised almost entirely of particles larger than 0.3 μm. On this basis, it was assumed that HE PA filters would generally remove 99.97 percent
of uncontrolled emissions from hard chro mium electroplating, decorative chromium electroplating, and chromi um anodizing sources.

Table 8. Particle Size Data for Uncontroll ed Hard Chromium Electroplating Emissions a

Particle Size, μm Cumulative % less than
8 82.6%
2.4 67.7%
0.5 6.9%

a Reference 3.

From a model plant perspective, Table 9 summarizes the resulting nationwide emissions of chromium compounds from hard chromi um electroplating, decorative chromium electroplating, and chro mium anodizing assuming all existing tanks are retrofit with HEPA6

filters. The table also shows the emissions reducti ons from baseline that would result from this option. Based on this analysis, retrofitting HEPA filters or all existing tanks subject to the NESHAP would reduce nationwide emissions by 3,121 lbs/yr (1.56 tons/yr) from 3,279 lbs/yr (1.64 tons/yr) to 158 lbs/yr (0.079 tons/yr).

Table 9. Estimated Emissions Reductions for HEPA Filter Retrofit - Model Plant Basis

Nationwide Emissions, lbs/yr

Electroplating Type Model Plant
Size Baseline HEPA Filter
Retrofit Net Emissions
Reductions
Small 499 18 481
Medium 995 44 952 Large 1,536 84 1,452 Hard Chromium

Total 3,030 146 2,884
Small 42 2.3 40
Medium 35 1.8 33 Large 130 5.9 124 Decorative Chromium

Total 207 10.0 197
Small 7.1 0.39 6.7 Large 35 1.6 33 Chromium Anodizing
Total 42 2.0 40 Nationwide total 3,279 158 3,121

With respect to emissions limits, the Chro mium Electroplating NE SHAP distinguishes between four types of plants: large hard chromium electro plating, small hard chromium electroplating, decorativ e chromium electroplat ing, and chromium anodizing. Large hard chromium electroplating plants are defined as those that have a maximum cumulative potential rectifier capacity of at least 60 million ampere-hours per year (amp-hr/yr), and small facilities are those with a maximum cumulative potential rectif ier capacity less than 60 million amp-hr/yr. These size distinctions differ from the model pl ant sizes for hard chromium electroplating. All large model plants would be classified as larg e hard chromium plants under the NESHAP, and all small model plants would be classified as small hard chromium pl ants under the NESHAP. However, the larger portion of me dium size model plants would be classified as small, and the
remainder would be classified as large under the NESHAP . For this analysis, it was assumed that 67 percent of the medium size model plants are small hard chromium plants under the NESHAP, and that those plants account for 33 percent of the emissions from medium size model plants. The remaining medium size model plants, and the emissions attributed to those plants, are assumed to represent large hard chromium plants under the NESHAP. Table 10 summarizes baseline emissions, emissions under the HEPA filter retrofit option, and the corresponding emissions reductions based on these assumptions.7

Table 10. Estimated Emissions Reductions fo r HEPA Filter Retrofit - NESHAP Basis

Nationwide Emissions, lbs/yr

Plant Type No. of plants Baseline HEPA Filter
Retrofit Net Emissions
Reductions Large Hard Chromium 132 2,200 113 2,087
Small Hard Chromium 658 831 33 797
Decorative Chromium 740 207 10.0 197 Chromium Anodizing 240 42 2.0 40 Total 1,770 3,279 158 3,121

III. HEPA Filter Retrofit Costs

This section describes the methodology, data, an d assumptions used to estimate the costs of retrofitting HEPA filters on existing sour ces subject to the Chromium Electroplating NESHAP. In estimating costs, distinctions we re made between emission control systems with existing add-on controls, and sources that use WA FS and are not equipped with add-on controls. For systems with existing add-on co ntrols, a retrofit factor was incorporated into the basic HEPA filter system cost. For systems without existing a dd-on controls, a retrofit factor was not applied to the costs. However, it was necessary to in clude costs of an exhaus t and ventilation system (hoods, ductwork, and fans) and a primary control device to remove the larger particles in the exhaust stream prior to the HEPA filter. The following sections provide additional details on
how these costs were estimated.

Sources with Existing Add-On Controls

Cost estimates were requested from thr ee vendors for the complete installation new HEPA filter systems on systems designed fo r four exhaust flow rates: 6,000, 12,000, 18,000, and 40,000 actual cubic feet per minute (ACFM). Estimates were received from Oskar Environmental Inc. of Youngsville, NC and Fl anders/CSC of Washingt on, NC. Because the quotes were for budgetary purposes , detailed itemization was not provided. The Flanders quote included an itemized list of compone nts, but only a total cost fo r each system. The Oskar quote was itemized by the following: 1) fan and HEPA housing; 2) ducti ng and installation; 3) estimated freight; and 4) filter replacement cost . The estimated freight and filter replacement costs were assumed equal to no rmalize the quotes for comparison. The quotes are presented in Appendix A of this document.

The capital and annual costs for each system were determined by the methods described
in the EPA Air Pollution Control Cost Manual (Reference 4)

. Presented in Table 11 are the capital costs categories and the source of thos e rates, if not provide d in the cost quotes.8

Table 11. Cost Components and Assumptions Used to Estimate HEPA Filter Retrofit Costs

Plant Type Oskar Environmental Flanders System Included Included Instrumentation Not included; assumed 11% of equipment cost Not included; assumed 11% of equipment cost
Sales tax Assumed 6% Assumed 6% Freight Included Not included (used Oskar quote) Installation Included Included, but not itemized (used Oskar quote) Performance testing Not included; assumed 0.7% of
installation cost Not included; assumed 0.7% of
installation cost Contingencies Assumed 2.1% of installati on cost Assumed 2.1% of installation cost Retrofit Cost Assumed 50% of capital cost Assumed 50% of capital cost

Table 12 presents the annual cost categories considered in the estimate, the assumptions used, and the information source. The filter re placement costs were provided in each quote, while the additional information was derived from various sources. For electricity costs, a unit price of $0.14 per kilowatt hour (k W-hr) was used (Reference 5).

Table 12. Annual Cost Components and Assu mptions Used for HEPA Retrofit Costs

Cost Component Source/Method
Labor hours CA ARB a Filter Replacement Quotes Filter Disposal $930/5000 ft 3 /min. a Electricity $0.14/kwhr Property Tax & Insurance 4% of capital cost b

a Reference 6.

b Reference 4.

The average total annual cost for each system was determined from the two quotes, and the resulting cost curve was determined using an interest rate of 7% a nd 20-year lifetime. The cost curve plotted exhaust flow (independent va riable) versus total a nnual cost (dependent variable) and resulted in a R 2 value of 0.999. The equation of the best-fit line was then used to
determine the total annual cost fo r the model facilities for hard plating, decorative plating, and anodizing facilities. Presented in Figure 1 is the cost curve fo r retrofitting a new HEPA filter system on a chromium electroplating source with existing add-on controls.9

Figure 1. Annualized Cost Curve for Retr ofitting new HEPA Filter on Existing Chromium Electroplating Source wi th Existing Add-on Controls.

The cost curve was used to estimate the co st per model plant, which was then multiplied by the number of plants nationwide. Based on this methodology, the estimated annualized cost to retrofit a new HEPA filter on all sources subj ect to the NESHAP with existing add-on controls is $53.7 million. Table 13 shows the detailed cost and number of facilities for each type of model plant.

Table 13. Nationwide Annualized Costs for HEPA Retrofit - Sources with Add-on Controls

Model
Plant Size Exhaust Flow Rate, ACFM Number of
Facilities Annualized Cost per Model Plant, $/yr Total Nationwide Annualized Cost, $/yr

Hard Chromium Electroplating Small 12,000 442 $39,909 $17,640,000 Medium 35,000 142 $91,220 $12,953,000 Large 70,000 79 $169,301 $13,375,000 Decorative Chromium Electroplating Small 12,000 59 $39,909 $2,355,000 Medium 24,000 22 $66,680 $1,467,000 Large 76,000 15 $182,686 $2,740,000 Chromium Anodizing Small 12,000 18 $39,909 $718,000 Large 40,000 24 $102,374 $2,457,000 Total Nationwide Annualized Costs $53,705,000

Sources without Existing Add-On Controls

For existing chromium electroplating and a nodizing sources that ar e not equipped with add-on controls, the same basic methodology was used as described in the previous paragraphs.10

However, the 50 percent retrofit factor was excl uded from the calculations, and the costs for installing an exhaust system and a primary control device were included. For the primary control device, it was assumed that a mesh pad mist elim inator (MPME) would be used. To estimate the cost of installing an exhaust system and MP ME, the cost model developed for the NESHAP (Reference 2) was used and converted to 2009 dollars using the C onsumer Price Index (Reference 7). The cost of a new HEPA filter syst em was added to these costs and a similar cost curve was developed. Figure 2 shows the resulting cost curve

Figure 2. Annualized Cost Curve for Retr ofitting new HEPA Filter on Existing Chromium Electroplating Source without Existing Add-on Controls.

The cost curve was used to estimate the co st per model plant, which was then multiplied by the number of plants nationwide. The resulting annualized cost to retrofit a new HEPA filter on all sources subject to the NESHAP without ex isting add-on controls was estimated to be $68.0 million. Table 14 shows a breakdown of the annua lized costs for these sources. Table 15 shows the combined annualized costs by model plan t type and size for existing sources with addon controls and sources without add-on controls. Total na tionwide annualized costs are estimated to be $121 million. Table 16 shows the same costs based on the source types and sizes specified in the NESHAP.11

Table 14. Nationwide Annualized Costs for HEPA Retrofit - Sources without Add-on Controls

Model
Plant Size Exhaust Flow Rate, ACFM Number of
Facilities Annualized Cost per Model Plant, $/yr Total Nationwide Annualized Cost, $/yr Hard Chromium Electroplating Small 12,000 111 $54,981 $6,103,000 Medium 35,000 16 $138,286 $2,213,000 Large 70,000 0 $271,566 $0 Decorative Chromium Electroplating Small 12,000 533 $55,524 $29,594,000 Medium 24,000 89 $98,627 $8,778,000 Large 76,000 22 $257,459 $5,664,000 Chromium Anodizing Small 12,000 162 $55,525 $8,995,000 Large 40,000 36 $185,712 $6,686,000 Total Nationwide Annualized Costs $68,033,000

Table 15. Nationwide Annualized Cost s for HEPA Retrof it - All Sources

Model Plant Size Number of
Facilities Total Nationwide Annualized Cost, $/yr Hard Chromium Electroplating Small 553 $23,743,000 Medium 158 $15,166,000 Large 79 $13,375,000 Decorative Chromium Electroplating Small 592 $31,949,000 Medium 111 $10,245,000 Large 37 $8,404,000 Chromium Anodizing Small 180 $9,713,000 Large 60 $9,143,000 Total Nationwide Annualized Costs $121,738,000

Table 16. Nationwide Annualized Costs for HEPA Retrofit - NESHAP Basis

Facility Type a Number of
Facilities Total Nationwide Annualized Cost, $/yr Large Hard Chromium 132 $18,425,000 Small Hard Chromium 658 $33,859,000 Decorative Chromium 740 $50,598,000 Chromium Anodizing 240 $18,856,000 Total 1,770 $121,738,000

a As defined in NESHAP.12

IV. Cost Effectiveness fo r HEPA Filter Retrofit

Table 16 presents the cost effectiveness for retrofitting HEPA filters on all existing tanks that are subject to the Chromium Electroplating NESHAP. The cost effectiveness ranges from $17.7 million per ton for large hard chromium elect roplating plants to $944 million per ton for chromium anodizing plants. Overall cost effect iveness was estimated to be $78 million per ton.

Table 16. Cost Effectiveness for HEPA Filter Retrofit

Cost Effectiveness Facility Type a Emissions reductions, lbs/yr Annualized costs, $/yr $/lb $/ton Large Hard Chromium 2,087 $18,425,000 $8,800 $17,700,000 Small Hard Chromium 797 $33,859,000 $42,500 $84,900,000 Decorative Chromium 197 $50,598,000 $256,900 $513,900,000 Chromium Anodizing 40 $18,856,000 $472,400 $944,800,000 Total 3,121 $121,738,000 $39,000 $78,000,000

a As defined in NESHAP.

V. References

1. Memorandum from R. Marinshaw, RTI Intern ational, to P. Mulrine, EPA/OAQPS.
Estimated Number of Chromium Electroplating Plants. May 24, 2010.

2. U.S. EPA. Chromium Emissions from Ch romium Electroplating and Chromic Acid Anodizing Operations -- Background Informati on for Proposed Standards, Volume I (EPA 453/R-93-030a). U.S. Environmental Protection Agency, Research Triangle Park, NC. July
1993.

3. U.S. EPA. Compilation of Air Pollutant Emission Factors, Volume 1, Stationary Sources, Section 12.20, Electroplating . U.S. Environmental Protection Agency, Research Triangle Park, NC. June 2006.

4. U.S. EPA. EPA Air Pollution Control Cost Manual, EPA/ 452/B-02-001. U.S. Environmental Protection Agency, Research Triangle Park, NC 2002.

5. South Coast Air Quality Management District. Final Socioeconomic Assessment for Proposed Amendments to Rule 1469 – Hexava lent Chromium Emissions from Chrome Plating and Chromic Acid Anodizing Operati ons and Proposed Rule 1426 – Emissions from Metal Finishing Operations . 2003.

6. California Air Resources Board. Proposed Amendments to the Hexavalent Chromium Airborne Toxic Control Measure for Ch rome Plating and Chromic Acid Anodizing Operations . 2003

7. U.S. Department of Labor, Bureau of La bor Statistics. http ://www.bls.gov/CPI/.