# BART Modeling Protocol:

PRAYON INC. Augusta, Georgia

Prepared by:

Ian Keefe ESH Engineer

April 30, 2006

## Contents

1.0 Introduction

............................................................................................................................... ................ 1-1

1.1 Objectives

............................................................................................................................... ......... 1-1

1.2 Location of source vs. relevant Class I Areas ................................................................................ 1-1

1.3 Organization of protocol document ................................................................................................. 1-1

2.0 Source description and emissions data ............................................................................................... 2-3

2.1 Unit-specific source data ................................................................................................................. 2-3

3.0 Input data to the CALPUFF model ......................................................................................................... 3-1

3.1 General modeling procedures: ....................................................................................................... 3-1

3.2 Air quality database (background ozone and ammonia) ............................................................... 3-1

3.3 Natural conditions and monthl y f(RH) at Class I Areas ................................................................. 3-1

4.0 Air quality modeling procedures ........................................................................................................... 4-1

4.1 Model selection and features .......................................................................................................... 4-1

4.2 Modeling domain and receptors ..................................................................................................... 4-1

4.3 Technical options used in the modeling ......................................................................................... 4-1

4.4 Light extinction and haze impact calculations ................................................................................ 4-1

5.0 Presentation of modeling results ........................................................................................................... 5-1

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## List of Tables

Table 2-1 The Augusta Plant modeling emission parameters ................................................................ 2-3



## List of Figures

Figure 1-1 Location of PSD Class I Areas in relation to The Augusta Plant ............................................ 1-2

ii March 2006

## 1.0 Introduction

1.1 Objectives
The Regional Haze Rule requires Best Available Retrofit Technology (BART) for any BART-eligible source that ‘‘emits any air pollutant which may reasonably be antici pated to cause or contribute to any impairment of visibility” in any mandatory Class I federal area. Purs uant to federal regulations, states have the option of exempting a BART-eligible source from the BART requirements based on dispersion modeling demonstrating that the source cannot reasonably be anti cipated to cause or contribute to visibility impairment in a Class I area. Therefore, this modeling protocol focuses on performing the BART modeling analysis for particulate matter (PM), SO 2 and NOx.

Several emission points at the Prayon Inc. manufactur ing facility, located near Augusta, Georgia, have been identified as BART-eligible sources. The purpose of th is document is to summarize the procedures by which a modeling analysis will be conducted for this source. The modeling procedures outlined will be used to determine whether the source is subject to BART require ments (exemption modeling). If it is determined that the source is subject to BART, then th e procedures will be used to evaluate th e visibility improvement factor in the BART determination step (determi nation modeling). The modeling proc edures are consistent with those outlined in the updated final VISTAS common BART modeli ng protocol (dated December 22, 2005, revision 2 – 3/9/06), available at http://www.vistas-sesarm.org/BART/ BARTModelingProtocol_rev2_9Mar2006.pdf . This source-specific BART modeling protoc ol references relevant portions of the common VISTAS modeling protocol.



### 1.2 Location of source vs. relevant Class I Areas
The Georgia Environmental Protection Division’s Air Protec tion Branch, which is in charge of the state’s BART program, has determined that several sources at Prayon Inc.’s Augusta, Georgia facility are BART-eligible for PM, SO 2 and NOx. Figure 1-1 shows a plot of the Augusta, Georgia facility relative to nearby Class I Areas. There are at least 3 Class I areas (possibly 6) within 300 km of the plant: Wolf Island Wilderness Area, Shining Rock Wilderness Area, and Cape Romain Wilderness Ar ea (possibly Linville Gorge Wilderness Area, Great Smoky Mountains NP, and Okefenokee Wilderness Area) . The BART 12-km exemption modeling will be conducted for each of these Class I areas in acco rdance with the referenced VISTAS common BART modeling protocol and the procedures described in this s ource-specific BART modeling protocol. If necessary, visibility improvement modeling for the BART determinati on step will be performed for those Class I areas where the exemption modeling shows a greater than 0.5 deciview impact.



### 1.3 Organization of protocol document
Section 2 of this protocol describes the source emissi ons that will be used as input to the BART exemption modeling and, if necessary, the BART determination modeli ng. Section 3 describes the input data to be used for the modeling including the modeling domain, terrain and land use, and meteorological data. Section 4 describes the air quality modeling procedures and Secti on 5 discusses the presentation of modeling results. Since all of the references cited are also included in the VISTAS common BART modeling protocol (Section 7.), no additional references section is included in th is document. Appendix A provides additional information on the baseline source emissions.

March 2006 1-1Figure 1-1 Location of Class I Areas in Relation to The Augusta Plant

Marc h 2 0 0 6 1- 2

## 2.0 Source description and emissions data

2.1 Unit-specific source data

The emissions data used to assess the vi sibility impacts at the Class I ar eas within 300 km of the Augusta Plant is discussed in this section. Since various components of PM 10 emissions have different visibility extinction efficiencies, the PM 10 emissions are divided, or “speciated,” into several components (VISTAS common protocol Sections 4.3.3 and 4.4.2). The VISTAS protocol (Section 5.) allows for the use of sourcespecific emissions and speciation factors or default values from AP-42. The PM 10 emissions and speciation approach to be used for the modeling described in this pr otocol is indicated in the bullets below. Where default speciation values are used, the data represents a unit where curr ent (baseline) emission controls include fabric filter dust collecti on systems, but no post-combustion NO x or SO 2 control equipment exists.

• Total PM 10 is comprised of emission calculations from last stack testing conducted.

• Total PM 10 filterable and condensable emissions.
In practice, CALPUFF allows for the user to input certain components of PM 10 as separate species and separate sizes, which will result in more accurate wet and dry deposition velocity results and also more accurate effects on light scattering.

Table 2-1 provides a summary of the modeling emi ssion parameters to be used in the BART CALPUFF modeling, consistent with the source emissions data.

If the BART exemption modeling indicates that a BART det ermination is required, then one or more particulate matter control options will be considered for the modeling to determine visibility im provement from the baseline case. The BART engineering analysis w ill provide the justifications for the selected, technically feasible options and the species-specific control efficiencies. Table 2-1 will be updated to provide the modeling parameters for these feasible options and resubmitted to Georgia EPD for review. Any site-specific deviations from the default particulate matter specia tion guidance would be outlined at that time.

Table 2-1 The Augusta Plant modeling emission parameters

Location UTM (Zone 44 NAD-83) Actual 24-hr. Max. Emissions Case Source / Unit UTM East UTM North Stack Ht Base Elev. Above

MSL Diameter Gas Exit Vel. Stack Gas Exit Temp. SO 2 NO X PM 10

km km Ft Ft Ft ft/s deg F lbs/hr lbs/hr lbs/hr
The Augusta Plant current

Mist Elim S101 408284.594 3694680.919 97 240 8.0 13.8 178 0 0 0 Mist Elim S102 408284.594 3694680.919 97 240 8.0 13.8 178 0 0 0 Reactor S201 408284.594 3694680.919 8 203 2.67 15.0 176 0 0 10 SMill DC S304 408284.594 3694680.919 18 233 0.83 52.5 200 0 0 0.29

1 Mill Heater 5221 408284.594 3694680.919 0 0 0 0 N/a 0.00 0.20 0.01 1 Mill 5219 408284.594 3694680.919 0 0 0
DC Heater 5227 408284.594 3694680.919 0.0 0.05 0.00 Vent DC S306 408284.594 3694680.919 22.5 233 0.83 52.5 100 0.0 0.0 0.29 Calc DC S305 408284.594 3694680.919 21.75 233 1.17 62 270 0.0 0.0 0.50

Calc heater 5406 408284.594 3694680.919 0.0 0.26 0.01

Bulk Ld DC S307 408284.594 3694680.919 22.5 233 0.83 52.5 77 0.0 0.0 0.29

2-3

## 3.0 Input data to the CALPUFF model

3.1 General modeling procedures:
VISTAS has developed five sub-regional 4-km CALMET meteorological databases for three years (2001- 2003) (VISTAS common protocol Section 4.4.2). Th e sub-regional modeling domains are strategically designed to cover all potential BART eligible sources with in VISTAS states and all PSD Class I areas within 300 km of those sources (to the nearest edge). The ext ents of the 4-km sub-regional domains are shown in Figure 4-4 of the VISTAS common BAR T modeling protocol. The BART modeling for The Augusta Plant will be done using the 4-km subdomain 4.

USGS 90-meter Digital Elevation Model (DEM) files were used by VISTAS to generate the terrain data at 4-km resolution for input to the 4-km sub-regional CALMET run. Likewise, USGS 90-meter Composite Theme Grid (CTG) files were used by VISTAS to generate the land us e data at 4-km resolution for input to the 4-km subregional CALMET run.

Three years of MM5 data (2001-2003) were used by VISTAS to generate the 4-km sub-regional meteorological datasets. See Sections 4.3.2 and 4. 4.2 in the VISTAS common BART modeling protocol for more detail on these issues.

It is intended that all of the modeling for The Augusta Pl ant will use the 4-km subdom ain 4. However, if the results indicate that the modeling could be improved wi th a CALPUFF run using a finer grid, then refinements in the modeling procedures will be considered and Georgi a EPD will be asked to approve these refinements.

In the event that a finer grid resolution is used, CALM ET must be rerun. Other modifications to inputs of CALMET would include the extent of the modeling domain, the resolution of the terrain and land use data, and other relevant settings. The same MM5 data and obs ervations as used for the 4-km sub-regional CALMET simulations would be used. The extent of the modeling domain may need to be changed because of disk space restrictions. The size of the CALMET output is di rectly proportional to the grid resolution of the run. The domain would be limited to the source and the exclus ive Class I area(s) being assessed with a higher grid resolution, including a 50-km buffer in all directions.

If CALMET needs to be run at even a finer grid resoluti on, then the appropriate model setting/files (specifically the GEO.DAT file) will be modified. A summary of thes e modifications would be provided to Georgia EPD for review and approval.



### 3.2 Air quality data base (background ozone and ammonia)
Hourly measurements of ozone from all non-urban moni tors, as generated by VISTAS and available on the VISTAS CALPUFF page on the Earth Tech web site (http://www.src.com/verio/download/sample_files.htm), will be used as input to CALPUFF. For ammonia, the approach recommended by VISTAS will be followed. However, since only PM emissions are being modeled, ozone and ammonia data is not really needed given that this data has no affect on PM results in CALPUFF.



### 3.3 Natural conditions and mont hly f(RH) at Class I Areas
For each of the applicable Class I areas, natural bac kground conditions must be established in order to determine a change in natural conditions related to a s ource’s emissions. The modeling described by this protocol document intends to use annual average natura l background light extinction (EPA 2003 values).

March 2006 3-1To determine the input to CALPUFF, it is first necessa ry to convert the deciviews to extinction using the equation:

Extinction (Mm-1) = 10 exp(deciviews/10).

For example, the EPA guidance document indicates for Great Smoky Mountains National Park that the deciview value for the average of the days is 7.60. This is equivalent to an ex tinction of 21.38 inverse megameters (Mm-1).

This extinction includes the default 10 Mm-1 for Ra yleigh scattering. The remain ing extinction is due to naturally occurring particles, and should be held constant fo r the entire year’s simulation. Therefore, the data provided to CALPOST for Great Smoky Mountains woul d be the total natural background extinction minus 10 (expressed in Mm-1), or 11.38. This is most easily input as fine soil concentrations (11.38 μ g/m3) in CALPOST, since the extinction effi ciency of soil (PM-fine) is 1.0 an d there is no f(RH) component. The concentration entries for all other par ticle constituents would be set to zero, and the fine soil concentration would be kept the same for each month of the year. The monthly values for f(RH) that CALPOST needs will be taken from "Guidance for Tracking Progress Under the Regional Haze Rule" (EPA, 2003) Appendix A, Table A-3.

March 2006 3-2

## 4.0 Air quality mo deling procedures

This section provides a summary of the modeling procedur es outlined in the VISTAS pr otocol that will be used for the refined CALPUFF analysis to be conducted for The Augusta Plant.



### 4.1 Model selection and features
As noted in the VISTAS protocol (Summary, Reco mmendations Section II.), VI STAS will use CALPUFF Version 5.754 and CALMET Version 5.7, which can be obtained at http://www.src.com/verio/download/download.htm#VISTAS_VERSION . These versions contain enhancements funded by the Minerals Management Servic e (MMS) and VISTAS. They were developed by Earth Tech, Inc. and they are maintained on Earth Tech’s Atmospheric Studies Group CALPUFF website for public access. This release includes CALMET, CALP UFF, CALPOST, CALSUM, and POSTUTIL as well as CALVIEW.

The major features of the CALPUFF modeling system , including those of CALMET and the post processors (CALPOST and POSTUTIL), are referenced in Section 3 of the VISTAS protocol.



### 4.2 Modeling domai n and receptors
The initial The Augusta Plant BART runs will use the sub-domain 4, 4-km CALMET data to be supplied by VISTAS, as discussed above. This domain includes all Cl ass I areas within 300 km of the source, plus a 50- km buffer. If there is the need for a refined analysis with a finer grid, a supplement to this modeling protocol will be provided describing the proposed procedures.

The receptors used for each of the Class I areas are based on the NPS database of Class I receptors, as recommended by the VISTAS common protocol (Section 4.3.3).



### 4.3 Technical options used in the modeling
CALMET modeling for the VISTAS-provided 4-km subdomai ns will be performed per the procedures specified in the VISTAS common BART modeling protocol. If it is decided to conduct additional modeling with a finer grid than 4 km, this modeling protoc ol will be updated to specify the te chnical options to be used in the CALMET run, in order to allow for state agency review and approval.

For CALPUFF model options, The Augusta Plant will follow the VISTAS common BART modeling protocol (Section 4.4.1), which states that we should us e IWAQM (EPA, 1998) guidance. The VISTAS protocol (Section 4.3.3) also notes that building downwash effects are not required to be included unless the state directs the source to include these effects. Since The Augusta Plant is several tens of kilometers from the nearest Class I area, building downwash effects will not be included in the CALPUFF modeling.

The POSTUTIL utility program (VISTAS common protocol Section 4.4.2) will be used to repartition HNO3 and NO3 using VISTAS-provided ammonia concentrations derived from previous 2002 CMAQ modeling conducted by EPA or the alternate ammonia concentrations approach recommended by VISTAS, if the CMAQ data is unavailable. As indicated earlier, since only PM em issions are being modeled, the treatment of ammonia should not have an affect on PM results from CALPUFF.



### 4.4 Light extinction and haze impact calculations
The CALPOST postprocessor will be used as prescribed in the VISTAS protocol for the calculation of the impact from the modeled source’s prima ry and secondary particulate matter concentrations on light extinction.

March 2006 4-1The formula that is used is the existing (not the November 2005 revised) IMPROV E/EPA formula, which is applied to determine a change in light extinction due to increases in the particulate matter component concentrations. Using the notation of CALPOST, the formula is the following:

b ext = 3 f(RH) [(NH4)2SO4] + 3 f(RH) [NH4NO3] + 4[OC] + 1[Soil] + 0.6[Coarse Mass] + 10[EC] + b Ray
The concentrations, in square brackets, are in ug/m3 and b ext is in units of Mm-1. The Rayleigh scattering term (b Ray ) has a default value of 10 Mm-1, as recommended in EPA guidance for tracking reasonable progress (EPA, 2003a). However, as recommended in the VISTAS prot ocol (Section 6.2.4), for refined 4-km grid (or smaller) CALPUFF runs, the Rayleigh scattering term will be modified for the specific elevation of the Class I area receptors. The Rayleigh term for estimating natu ral background will also, be adjusted to be consistent with this approach.

The assessment of visibility impacts at the Class I areas will use CALPOST Method 6 (VISTAS common protocol Section 4.3.2). Each hour’s source-caused exti nction is calculated by first using the hygroscopic components of the source-caused concentrations, due to ammonium sulfate and nitrate, and monthly Class I area-specific f(RH) values. The cont ribution to the total source-caused extinction from ammonium sulfate and nitrate is then added to the other, non-hygroscopic com ponents of the particulate concentration (from coarse and fine soil, secondary organic aerosols, and from elemental carbon) to yi eld the total hourly source-caused extinction.

The BART rule significance threshold for the contribution to visibility impairment is 0.5 deciviews. The VISTAS protocol (Section 4.3.2) indicates that with the use of the 4-km sub-regional CALMET database, a source does not cause or contribute to visibility impairment if the 98th percentile (or 8th highest) day’s change in extinction from natural conditions does not exceed 0.5 deciviews for any of the modeled years (an added check is: the 22nd highest prediction over the three years modeled should also not exceed 0.5 deciviews for a source to be exempted from a BART determination).

Figure 4-1 of the VISTAS common BAR T modeling protocol presents a fl ow chart showing the components of that modeling protocol for t he analysis to determine whether a source is subject to BART. Again, it should be noted that the modeling for The Augusta Plant will fo cus on Subregional Fine-Scale modeling as depicted in the lower half of the figure.

If the exemption modeling demonstrates that The Augusta Plant does not cause or contribute to visibility impairment, then the source will no t be subject to BART requirements, and no further analysis is needed. Otherwise, the source will proceed to perform BART determination modeling for the baseline and each control option in a similar manner as has been described in this document. This protocol will be supplemented with a revised Table 2-1 if the source is determined to be subject-to-BART.

March 2006 4-2

## 5.0 Presentation of modeling results

The BART exemption and, if necessary, the BART deter mination modeling results for the Augusta Plant will be provided to the state agency in a manner as described in the VISTAS protocol (Section 4.5). A report will be produced that includes the following elements (a s suggested in the VISTAS protocol):

1. A map of the source location and Class I areas within 300 km of the source.

2. For the CALPUFF modeling domain, a table listing all Class I areas in the VISTAS domain and those in neighboring states and impacts from the BART 4-km grid exemption modeling at those Class I areas within 300 km of the source, as illust rated in Table 4-3 of the VISTAS protocol.

3. A discussion of the number of Class I areas with visibility impairment due to source emissions for the 98th percentile days in each year (and the 98th percent ile over all three years modeled) greater than 0.5 dv.

4. For the Class I area with the maximum impact, a discussion of the number of days beyond those excluded (e.g., the 98th percentile for refined analyses) that the impact of the source exceeds 0.5 dv, the number of receptors in the Class I area where the impact exceeds 0.5 dv, and the maximum impact.

5. For any finer grid CALPUFF exemption modeling, re sults for those Class I areas for which impacts of the source exceeded 0.5 dv in the 4-km initial mode ling. We would report the same type of results as provided for 4-km exemption modeling.

The BART determination modeling will be performed fo r those Class I areas shown in the exemption modeling to exceed 0.5 dv impact. The extent of the BART determination modeling results will depend on the number of technically viable controls identified in the engineeri ng analysis phase of the BART assessment. The results presented will be a comparison of the 98 th percentile value for the baseline and each control strategy derived as is outlined above for the exemption modeling. The same statistics as those mentioned above in Steps 3 and 4 would be provided, and a summary of the relati ve results among all emission scenarios run would be produced.

Additionally, the appropriate electronic files used to conduct the CALPUFF modeling will be submitted on CDROM or DVD media.

March 2006 5-1