BART DETERMINATION FOR INTERSTATE PAPER

Interstate Resources Incorporated owns and operates paper facility called Interstate Paper 

located in Riceboro, Georgia. Interstate Paper is located within 100 Km of Wolf Island 

Class I area and Okefenokee Wilderness Class I area. 

To be BART eligible a source must fall within one of the 26 BART eligible source 

categories included in Clean Air Act, The source must have been in existence on August 

7, 1977 and must have began operation after August 7, 1962 and the source must have 

potential emissions of visibility impairing pollutant of 250 tons per year or more. Three 

of Interstate Paper’s units satisfy these criteria and hence are BART eligible. These three 

units are Power Boiler (F1), Recovery Boiler (F3), and Lime Kiln (F4). 

INTRODUCTION TO BART ANALYSIS 

The Best Available Retrofit Technology (BART) analysis follows the “five factor” 

approach. The basic steps of a “five factor” analysis are as follows: 

1. Cost of Controls 

2. Energy and non-air quality environmental impacts 

3. Existing controls at the source 

4. Remaining useful life of the source 

5. Visibility improvement reasonably expected from the controls 

A detailed description of cost of controls for BART-subject units at Interstate Paper, LLC 

mill in Riceboro, Georgia is given in the BART engineering analysis section. Most of the 

control costs were obtained from AirControlNET-4.1. Fuel switching cost was based on 

the facilities fuel usage and the cost of fuel in 2007 based on number provided by the 

facility itself. This section also gives an in-depth description and usage of the existing 

controls at the source. 

There are no known energy and non-air quality environmental impacts related to BART 

determined controls for Interstate paper, LLC. Remaining useful life of the source is 

BART Determination – Interstate Paper 1
known to be at least 10 years. Visibility improvement reasonably expected from 

application of the controls is described in the modeling analysis section. 

Georgia EPD performed the five steps for each visibility-affecting pollutant emitted from 

the BART-subject units. Relevant pollutants are only: sulfur dioxide (SO2), nitrogen 

oxides (NOx) and particulate matter (PM10). The following sections provide detailed 

engineering and modeling analysis for each BART-subject unit. 

1.0 ENGINEERING ANALYSIS METHODOLOGY

The Best Available Retrofit Technology (BART) engineering analysis in this application 

follows the “top-down” approach. The “top-down” approach starts with the most 

stringent control technology alternative that has been applied to similar sources and 

provides a basis for rejecting this alternative in favor of the next most stringent 

technology or proposing it as BART. The basic steps of a “top-down” analysis are as 

follows: 

1. Identify all control strategies 

2. Eliminate technically infeasible options 

3. Rank remaining control strategies by control effectiveness or efficiency 

4. Eliminate economically infeasible ones 

5. Evaluate most effective controls and document results for BART recommendation 

Georgia EPD performed the five steps for each visibility-affecting pollutant. Georgia 

EPD has determined that the relevant pollutants are only: sulfur dioxide (SO2), nitrogen 

oxides (NOx) and particulate matter (PM10). 

The following sections provide a detailed engineering analysis for each BART-eligible 

unit. 

2.0 BART ENGINEERING ANALYSIS FOR RECOVERY BOILER

2.1 SOURCE DESCRIPTION 

BART Determination – Interstate Paper 2
The Recovery Boiler (F3) is a low odor, indirect contact evaporator design. It fulfills the 

following essential functions: 

1. Evaporates the residual moisture from the black liquor solids. 

2. Burns the organic constituents. 

3. Produces steam. 

4. Produces sodium carbonate and sodium sulfides in molten form 

 Black liquor with more than 68% solids is fired into the recovery boiler where the 

organics from the black liquor are burned off in a reducing atmosphere generating steam, 

molten sodium carbonate and sodium sulfides. 

Air pollutants emitted from the recovery boiler include all the three BART relevant 

pollutants i.e. sulfur dioxide (SO2), 2.46 tons/yr, nitrogen oxides (NOx), 349.92 tons/yr, 

and particulate matter (PM10), 0.5 tons/yr. Emissions of the Recovery Boiler currently 

pass through a venturi scrubber. 

2.2 PARTICULATE MATTER 

Step 1.0-Identification of Control Technologies 

Emission control equipments that may be considered to control particulate matter 

emissions from recovery boilers include ESP’s, baghouses and high efficiency wet 

scrubbers. Each of these types of control equipments is capable of significantly reducing 

particulate matter emissions. 

Step 2.0-Technical feasibility Analysis of the identified Control Technologies

While baghouses can achieve high levels of particulate matter control, the exhaust gas 

streams from recovery boilers have relatively high moisture contents that cause the 

particulate matter to be hydroscopic in nature. These characteristics of the gas will result 

in clogging up of the bag filters in the baghouse. This indicates that baghouses are not a 

good control option for recovery boilers. Therefore, baghouses are not considered further 

as part of this BART analysis. 

BART Determination – Interstate Paper 3
ESP’s and wet scrubbers are feasible technologies for reducing particulate matter 

emissions from recovery boilers, with ESP’s having 99+% of control efficiency and wet 

scrubbers having 98+% of control efficiency. 

Step 3.0-Control Efficiency and Cost Evaluation 

An ESP has a slightly better control efficiency as compared to wet scrubber but the 

recovery boiler at the facility already uses a venturi scrubber to control PM emissions. 

Thus it is economically infeasible to install an ESP for a control efficiency enhancement 

of about 1% and incur an expenditure of about $ 68,239,64 (includes capital investment, 

installation, maintenance, and cost per ton of reduction achieved). Approximately similar 

control efficiency can be obtained without any additional cost. 

Step 4.0-Control Technology Selected for BART 

The unit already utilizes a venturi scrubber to control particulate matter emissions, no 

additional controls are proposed. 

2.3 NITROGEN OXIDES 

Step 1.0-Identification of Control Technologies 

Emission control equipments that may be considered to control nitrogen oxide emissions 

from recovery boilers include combustion modification techniques and post-combustion 

controls. 

Combustion Modification Techniques 

A number of combustion modification techniques are available for reducing NOx

emissions from boilers in general. These include: 

• Staged air combustion 

• Low NOx burner with flue gas recirculation system 

• Oxygen trim and water injection 

The combustion modification techniques listed above reduce NOx by minimizing its 

formation in the combustion chamber of the boiler or by using less oxygen than is 

stoichiometrically required for complete combustion of the fuel. 

BART Determination – Interstate Paper 4
Post-Combustion Controls 

The technologies for post-combustion control include: 

• Selective non-catalytic reduction (SNCR) 

• Selective catalytic reduction (SCR) 

Step 2.0-Technical feasibility Analysis of the identified Control Technologies 

• Staged air combustion is integral to the operation of most recovery boilers, is the 

most effective strategy for minimizing NOx formation in a recovery boiler hence, 

is technically feasible. As such, it is also integral to the operation of most 

recovery boilers. The recovery boiler at the Riceboro mill currently employs 

staged air combustion with primary, secondary and tertiary combustion air. A 

fourth level of staged air combustion cannot be added, as it would require a new 

recovery boiler and cannot be considered as a retrofit control. 

• Use of a low NOx burner is of minimal value for NOx reduction because the 

primary fuel of the recovery boiler is black liquor. 

• Flue Gas Recirculation has not been commercially applied to Babcock & Wilcox 

furnaces. Furthermore, the reducing atmosphere needed to convert sulfate 

compounds to sulfide compounds in the lower furnace tends to preclude FGR in 

the lower furnace. In other words, FGR wouldn't provide any measurable NOx 

reduction on the recovery boiler, if applied to the lower furnace. Use of FGR may 

also unreasonably restrict throughput and create safety issues due to anticipated 

smelt bed control problems, if applied to the lower furnace. There may be some 

benefit to FGR application above the tertiary air level but such has not been 

commercially applied. 

• Kraft recovery boilers already employ some method of oxygen trim due to the 

reduction atmosphere demanded by the process itself. Interstate Paper typically 

targets 3 to 4 % excess oxygen at the economizer, which trims air combustion in 

response. The use of more advanced oxygen trim methods probably won’t provide 

any measurable impact on NOx. Thus use of further oxygen trim is not technically 

feasible. 

BART Determination – Interstate Paper 5
• Water injection cannot be considered due to its' inherently dangerous nature for 

Kraft recovery furnaces. Thus water injection is technically infeasible and will not 

be further considered for BART analysis 

• SNCR as a control option for flue gas treatment is technically not very feasible 

based on the fact that SNCR systems work by injecting ammonia or urea into the 

combustion chamber of the boiler, thereby converting NOx to elemental nitrogen, 

carbon dioxide, and water vapor. The recovery boiler is a complete, chemical 

reaction system and any disruption of the delicate chemistry could possible 

damage the boiler, impact the quality of the product, or otherwise affect the 

system unacceptably. The injection of ammonia gas or urea solution would have a 

detrimental effect upon the chemistry inside the boiler. Thus usage of SNCR as a 

NOx control for recovery boilers is infeasible and will not be further considered 

for BART analysis. 

• The technical feasibility of a SCR system for treatment of flue gases generated 

from recovery boiler is questionable. The toxic metals present in the flue gas 

exhaust are of sufficient quantity to build up on the surface of the catalyst bed and 

poison the catalyst within a relatively short period of time. Thus SCR is also 

technically infeasible for a recovery boiler and will not be further considered for 

BART analysis. 

Step 3.0-Control Efficiency and Cost Evaluation 

No control technology was technically feasible. 

Step 4.0-Control Technology Selected for BART 

No additional BART controls are proposed. 

2.4 SULFUR DIOXIDE 

Step 1.0-Identification of Control Technologies 

Emission control equipments that may be considered to control sulfur dioxide emissions 

from recovery boilers include any number of absorption (i.e., scrubbing) processes, flue 

BART Determination – Interstate Paper 6
gas desulfurization (FGD), combustion control and usage of high black liquor solid 

content. 

 Step 2.0-Technical feasibility Analysis of the identified Control Technologies 

• Gas absorption systems are designed to maximize contact between the gas and 

liquid in order to permit interphase diffusion of the SO2. Absorbers found to 

adequately disperse the liquid include packed towers, plate or tray towers and tray 

chambers. SO2 emission reductions of 90-98% can be expected by usage of gas 

absorption systems. However if the pollutant concentration entering the absorber 

is relatively low, then SO2 removal efficiency will be much lower. Thus gas 

absorption systems are feasible control equipments for reduction of SO2

emissions. 

• Combustion control and high black liquor solids content are effective means to 

control SO2 emissions from recovery boilers. SO2 emissions are formed by the 

oxidation of reduced sulfur compounds in recovery boilers. These emissions vary 

depending upon the sulfur content of the black liquor being burned, the quantity 

of oxygen available in the combustion chamber and the black liquor solids 

content. Higher black liquor solids content, yields lower SO2 emissions. Thus 

combustion control and black liquor solid contents are feasible control 

technologies for SO2 emissions from the recovery boiler. 

• Flue gas desulfurization technology is used on coal-fired boilers and works in one 

of the two ways. The first method works by injecting dry limestone into the 

combustion chamber of the boiler, where limestone reacts with sulfur dioxide 

gases to form calcium sulfate. Injection of chemicals into the combustion chamber 

of the recovery boiler as a means to control SO2 emissions will interfere with the 

recovery process that is taking place inside the boiler. For this reason flue gas 

desulfurization using “dry limestone” method is not considered technically 

feasible for reduction of SO2. Additionally, there are no known recovery boilers 

in the U.S utilizing this particular type of SO2 control. The second method works 

by adding a wet slurry of limestone into a scrubber that is controlling the flue gas 

from the boiler. Limestone reacts to form calcium sulfate in the slurry form. 

Usage of wet limestone outside the boiler is technically feasible and would lead to 

BART Determination – Interstate Paper 7
a removal efficiency of 90% or higher depending on the SO2 content in the flue 

gas. 

 

Step 3.0-Control Efficiency and Cost Evaluation 

• Gas absorption systems are technically feasible control systems involving high 

capital investment and installation costs of about $166,5000. These systems 

usually have high-pressure drops in the range of 6-8 inches w.c. This may require 

additional expenditure for a new fan, which should be designed to handle that 

pressure drop. These systems also require routine maintenance and hence would 

also involve high maintenance cost. Thus they cannot be considered as BART 

controls because of their economic infeasibility. 

• Combustion control along with being a technically feasible means of controlling 

SO2 emissions is also inherent in the design of a recovery boiler due to the 

chemical reactions that take place inside of the combustion chamber when black 

liquor is combusted. Black liquor normally contains a number of sulfur-bearing 

compounds when it is generated from the Kraft pulping process. When black 

liquor is oxidized, most of the oxidized sulfur compounds are converted into 

sulfides. These inorganic compounds, primarily sodium sulfide and sodium 

sulfate, recovered in molten form at the bottom of the bed, are referred as “smelt”. 

The smelt is drained through the bottom of the recovery boiler into a smeltdissolving tank. The majority of the sulfur compounds that leave the smelt bed as 

sodium fume from the reduction process are tied up with boiler bottom ash as 

sodium sulfate, there by reducing SO2 emissions discharged from the boiler. The 

capture of SO2 is primarily dependent upon the boiler bed temperature. An 

increase in the dry solids content raises the temperature at the bottom part of the 

furnace thus reducing SO2 emissions. Thus a control efficiency of 99+% can be 

obtained without the usage of any additional control technology. Hence 

combustion control with high solids content is economically feasible control for 

SO2 emissions from the recovery boiler. 

• Flue gas desulfurization technique with wet limestone slurry is technically 

feasible but would involve additional equipment capital, installation and 

maintenance cost of about $ 290,6000 and lead to SO2 removal efficiency of 

BART Determination – Interstate Paper 8
about 90% which is less than what can be achieved by combustion control and 

high black liquor solids content. Hence it’s not considered to economically 

feasible and will not be further considered for BART analysis of the recovery 

boiler. 

Step 4.0-Control Technology Selected for BART 

Presence of black liquor solids content of up to 68% or more along with inherent design 

of the recovery boiler satisfies the requirement of combustion control technology thus 

leading to a control efficiency of 99+%. Thus no additional BART control is suggested. 

3.0 BART ENGINEERING ANALYSIS FOR LIME KILN

3.1 SOURCE DESCRIPTION 

The lime kiln dries and processes lime mud from the causticizing system by burning fuel 

oil with sulfur content no greater than 2.5%. The lime kiln is permitted to burn natural 

gas, No. 6 fuel oil, or limited quantities of used oil. It is equipped with a venturi scrubber 

to control particulate matter emissions. The lime kiln also serves as a back-up 

combustion device for low-volume, high concentration (LVHC) non-condensable gases 

(NCGs) generated in the pulp mill. 

Air pollutants emitted from the Lime Kiln include all the three BART relevant pollutants 

i.e. sulfur dioxide (SO2), 9.50 tons/yr, nitrogen oxides (NOx), 149.16 tons/yr, and 

particulate matter (PM10), 127.56 tons/yr. Emissions of the Lime Kiln currently pass 

through a venturi scrubber. 

3.2 PARTICULATE MATTER 

Step 1.0-Identification of Control Technologies 

Emission control equipments that may be considered for particulate matter control are 

baghouses, cyclonic separators, venturi scrubbers, other wet scrubbers and a combination 

of a venturi scrubber and ESP. 

BART Determination – Interstate Paper 9
Step 2.0-Technical feasibility Analysis of the identified Control Technologies 

All the above-listed technologies other than baghouses are technically feasible for 

removal of particulate matter from the lime kiln exhaust gas. 

Step 3.0-Control Efficiency and Cost Evaluation 

Table 1.0 ranks all the technically feasible control technologies based on top control 

efficiency values. The lime kiln at Interstate paper is currently equipped with a venturi 

scrubber. The venturi scrubber primarily uses fresh water as the scrubbing media. As 

shown in Table 1.0, the control efficiency that can be achieved with a venturi scrubber is 

about 98-99%. Cyclones are not considered because their control efficiencies are lesser 

than that of a Venturi scrubber. A venturi scrubber along with an ESP shows an increase 

in the control efficiency by about 1%. Installation of an ESP in combination to the venturi 

scrubber would approximately cost $5,495,014/yr. Hence it’s economically infeasible to 

endure such a high expense for an efficiency increase of about 1% only. 

Table 1.0. Ranking of Particulate Matter Control Equipments for Existing lime kilns 

Control Technology Removal Efficiency 

Venturi Scrubber and ESP 99.9%+ 

Venturi Scrubber 98-99% 

Dry/Wet ESP 98-99% 

Packed Bed Wet Scrubber 85+% 

Cyclone Separator 25-95% 

Step 4.0-Control Technology Selected for BART 

A venturi scrubber is the second most effective technology for removing particulate 

matter from lime kiln exhaust. Because the unit already utilizes a venturi scrubber to 

control particulate matter emissions, no additional controls are proposed. 

3.3 NITROGEN OXIDES 

BART Determination – Interstate Paper 10
Step 1.0-Identification of Control Technologies 

Emission control equipments that can be considered for control of nitrogen oxide 

emissions from the lime kiln are low NOx burners, SNCR-NH3 based, SNCR-urea based 

and SCR. 

Step 2.0-Technical feasibility Analysis of the identified Control Technologies 

All the above-mentioned control equipments are technically feasible for removal of 

nitrogen oxide from the lime kiln exhaust. 

Step 3.0-Control Efficiency and Cost Evaluation 

Table 2.0 ranks all the technically feasible control technologies based on top control 

efficiency values. 

Table 2.0. Ranking of Nitrogen Oxide Control Technologies for Existing Lime Kilns

Control Technology Removal Cost Evaluation 

Efficiency Capital + 

Operation 

Cost ($) 

Cost/ton of NOx

reduction ($/ton) 

Total 

Annual 

cost ($) 

SCR 80% 208,793,6 4,450 424,647 

Fuel Switch to burning 

of Natural Gas only 

73% 0 4,320 105,027.5

Low NOx burner 50% 144,242 740 26,461 

SNCR-Urea based 50% 174,006 1,017 60,641 

SNCR-NH3 based 30% 263,593 1,123 66,942 

The low-NOx burner control option and the two SNCR control options are considered to 

be economically feasible. However, they are not considered further as retrofit controls 

because of the relatively small benefit to visibility of NOx controls. Comparison of the 

visibility benefits of SO2 control versus NOx control is presented in Section 5.0. 

Step 4.0-Control Technology Selected for BART 

All the above-mentioned technologies are economically infeasible and cannot be 

considered as retrofit controls. Hence, no additional BART controls are suggested for the 

NOx emissions of the lime kiln at the Riceboro mill. 

BART Determination – Interstate Paper 11
3.4 SULFUR DIOXIDE 

Step 1.0-Identification of Control Technologies 

Emission control equipments that can be considered for control of sulfur dioxide are gas 

absorption with caustic scrubber; wet scrubber with lime mud; and use of low sulfur 

fuels. 

Step 2.0-Technical feasibility Analysis of the identified Control Technologies 

All the above-mentioned control equipments are technically feasible for removal of sulfur 

dioxide from the lime kiln exhaust. 

Step 3.0-Control Efficiency and Cost Evaluation 

The control efficiency of a gas absorber with caustic scrubbing is similar to that of a wet 

scrubber with lime mud. Each of these technologies can reduce sulfur dioxide emissions 

by up to 95%. Reducing the oil from 2.5% sulfur content to a low-sulfur fuel will show a 

control efficiency of approximately 50%. 

Step 4.0-Control Technology Selected for BART 

The lime kiln at Interstate Paper utilizes a venturi scrubber (wet scrubber) for particulate 

matter control. This scrubber further augments the SO2 removal process since the 

scrubbing solution becomes alkaline from the captured lime dust, consequently the lime 

kiln emits a very low level of SO2. Hence, no additional SO2 controls are proposed. 

4.0 BART ENGINEERING ANALYSIS FOR POWER BOILER

4.1 SOURCE DESCRIPTION 

The Power Boiler at Interstate Paper was installed in 1968 and has a maximum heat input 

of 400 MMBTU/hr. It fires natural gas and No. 6 fuel oil. The power boiler, along with 

the lime kiln, is used as a backup control device and it burns non-condensable gases too. 

Air pollutants emitted from the Power Boiler include all the three BART relevant 

pollutants i.e. sulfur dioxide (SO2), 300.49 tons/yr, nitrogen oxides (NOx), 409.24 tons/yr, 

and particulate matter (PM10), 19 tons/yr. 

BART Determination – Interstate Paper 12
4.2 PARTICULATE MATTER 

Step 1.0-Identification of Control Technologies 

Emission control equipments and technologies that may be considered for particulate 

matter controls are ESP, fabric filter and fuel switch to natural gas. 

Step 2.0-Technical feasibility Analysis of the identified Control Technologies 

All the above-mentioned control technologies are technically feasible for removal of 

particulate matter from the exhaust gases of the power boiler. 

Step 3.0-Control Efficiency and Cost Evaluation 

Table 3.0 ranks all the technically feasible control technologies and their total annual 

cost. 

Table 3.0. Ranking of Particulate matter Control Technologies for Existing Power Boilers 

Control Cost Evaluation 

Technology 

Removal 

Efficiency Capital + 

Operation 

Cost ($) 

Cost/ton of PM 

reduction 

($/ton) 

Total Annual 

cost ($) 

Fuel Switch to 

Natural Gas

99% 0 5,705 102,000 

ESP 98-99% 4,129,230 19,364 1,705,983 

Fabric Filter 98-99% 3,355,180 79,470 1,782,035 

ESP and fabric filter are technically feasible controls for PM emission reduction, but 

there are high capital and maintenance costs which cause them to be economically 

infeasible for BART and hence will not be further considered for BART analysis. 

Step 4.0-Control Technology Selected for BART 

The fuel switch to natural gas gives a particulate matter removal efficiency of more than 

99%. The cost that the facility will incur for such a fuel switch is also relatively less than 

BART Determination – Interstate Paper 13
the addition of control equipment. Along with reduction in PM emissions, reduction in 

NOx and SO2 will also be achieved therefore fuel switch to natural gas is an economically 

feasible option. Hence in the power boiler at the Riceboro mill, it is recommended to 

burn natural gas only, other than during periods of curtailment (i.e. reduction or 

discontinuance of natural gas supply). 

4.3 NITROGEN OXIDES 

Step 1.0-Identification of Control Technologies 

Emission control equipments and technologies that may be considered for nitrogen oxide 

controls are low NOx burner, low NOx burner with flue gas recirculation, SCR, SNCR 

and fuel switch to natural gas. 

Step 2.0-Technical feasibility Analysis of the identified Control Technologies 

All the above-mentioned control technologies are technically feasible for removal of 

nitrogen oxides from the exhaust gases of the power boiler. 

Step 3.0-Control Efficiency and Cost Evaluation 

Table 4.0 ranks all the technically feasible control technologies and their total annual 

cost. 

Table 4.0. Ranking of Nitrogen Oxide Control Technologies for Existing Power Boilers 

Control Cost Evaluation 

Technology 

Removal 

Efficiency Capital + 

Operation 

Cost ($) 

Cost/ton of 

NOx reduction 

($/ton) 

Total Annual 

cost ($) 

SCR 80% 304,095 1,955 30,241 

Low NOx Burner 

+ Flue Gas 

Recirculation 

60% 104,006 1,479 17,163 

Low NOx Burner 50% 30,838 528 5,108 

SNCR 50% 313,418 3,407 32,948 

BART Determination – Interstate Paper 14
Fuel Switch to 

Natural Gas

13% 0 29,800 102,000 

SCR, Low NOx burner; Low NOx burner with flue gas recirculation are economically 

feasible controls for NOx emission reduction. However, they are not considered further 

for BART analysis because of the relatively small benefit to visibility of NOx controls. 

Comparison of the visibility benefits of SO2 control and NOx control is presented in 

Section 5.0. 

Step 4.0-Control Technology Selected for BART 

Along with reduction in NOx emissions, reduction in PM and SO2 emissions can also be 

achieved by “fuel switch to natural gas” thus, it is an economically feasible option. 

Therefore, it is recommended that only natural gas be permitted as fuel in the power 

boiler at Riceboro mill, other than during periods of curtailment (i.e. during reduction or 

discontinuance of supply in natural gas). 

4.4 SULFUR DIOXIDE

Step 1.0-Identification of Control Technologies 

Emission control equipments and technologies that may be considered for sulfur dioxide 

controls are venturi scrubbers with caustic addition, spray dry scrubbers, dry scrubbers 

and fuel switch to natural gas. 

Step 2.0-Technical feasibility Analysis of the identified Control Technologies 

All the above-mentioned control technologies are technically feasible for removal of 

sulfur dioxide from the exhaust gases of the power boiler. 

Step 3.0-Control Efficiency and Cost Evaluation 

Table 5.0. Ranking of Sulfur Dioxide Control Technologies for Existing Power Boilers 

Control Removal Cost Evaluation 

BART Determination – Interstate Paper 15
Technology Efficiency Capital + 

Installation + 

Operation 

Cost ($) 

Cost/ton of 

SO2 reduction 

($/ton) 

Total Annual 

cost ($) 

Fuel Switch to 

Natural Gas

99+% 0 370.00 102,000 

Wet Scrubber w/ 

caustic? (venturi) 

90% 2,377,636 1,630 528, 246 

Spray Dry 

Scrubber 

80-90% NA NA NA 

Dry Scrubber 50 to 80% NA NA NA 

Fuel switch and wet scrubber are technically feasible. The cost per ton of SO2 emission 

reduction of each alternative is well within the range that EPA considers economically 

feasible. Hence both the techniques will be further considered for BART analysis. 

Step 4.0-Control Technology Selected for BART 

Both the above-mentioned technologies are economically feasible. Natural gas has higher 

control efficiency at lower cost as compared to a wet scrubber. Therefore it is 

recommended that power boiler at Riceboro mill burn natural gas only, other than during 

curtailment periods (i.e., during reduction or discontinuance of supply in natural gas). 

5.0 COMPARISON OF IMPACTS OF SO2 AND NOX CONTROLS ON 

VISIBILITY 

Georgia Tech performed a study for EPD that compared the impacts of statewide 

reductions of point SO2 and point NOx emissions on visibilities at the Wolf Island and 

Okefenokee Class I areas (see Appendix A). The metric used for visibility improvement 

was light extinction (specifically reduction of light extinction), expressed in units of 

inverse megameters (Mm-1). The study found that a statewide reduction of one ton per 

year of point SO2 emissions would effect estimated light extinction reductions of 1.97 x 

10-5 Mm-1 at Wolf Island and 2.59 x 10-5 Mm-1 at Okefenokee. A one-ton-per-year 

BART Determination – Interstate Paper 16
reduction of point NOx emissions (statewide) would achieve estimated reductions in light 

extinction of 0.319 x 10-5 Mm-1 at Wolf Island and 0.159 x 10-5 Mm-1 at Okefenokee. 

The ratios of light extinction reduction from SO2 reduction to light extinction reduction 

from NOx reduction are then 6.2 at Wolf Island and 16.4 at Okefenokee. SO2 reductions 

are therefore expected to provide substantially more visibility improvement than NOx 

reductions at both of these Class I areas. 

Sections 3.3, 4.3, and 4.4 evaluate potential BART control options for Interstate Paper’s 

Lime Kiln and Power Boiler emissions. Using the results of the Georgia Tech study and 

EPD’s calculations of visibility impacts due to SO2 reductions at specific emissions 

sources, it is possible to estimate the total visibility improvements for the potential 

control technologies. The visibility improvements are presented only for Wolf Island 

since it has been determined (Section 7.1) that the benefits of Interstate Paper emissions 

controls on visibility at Okefenokee are too small to be considered. The SO2 visibility 

impact (0.000076 Mm-1/tpy) used in this calculation is based on site-specific modeling 

performed by EPD of the impact of Interstate Paper’s SO2 emissions on light extinction 

at Wolf Island (Appendix N.1, Table 1). This is believed to be a more accurate estimate 

of the impact than the SO2 impacts determined from the statewide emissions impact 

study. 

The NOx visibility impact is then determined by applying the ratio (1/6.2) of the NOx 

impact to the SO2 impact (from the state-wide study) to the site-specific SO2 visibility 

impact, resulting in 0.000013 Mm-1/tpy. Note that EPD did not directly model the 

impact of NOx reductions at specific sites on visibility. 

These impacts (0.000076 Mm-1/tpy and 0.000013 Mm-1/tpy) are then applied to the 

specific emissions reductions associated with the potential control options. Tables 5.1 

and 5.2 show the light extinction reductions associated with the potential control options 

presented in Sections 3 and 4 for the lime kiln and the power boiler. The light extinction 

reductions from the SO2 control options range from 0.0147 to 0.0225 Mm-1. The light 

extinction reductions from the NOx control options range from 0.0006 to 0.0041 Mm-1. 

BART Determination – Interstate Paper 17
Due to the lower extinction reductions (visibility improvements) for the NOx controls 

they were excluded from further consideration as feasible BART control options. 

Table 5.1. Interstate Paper Lime Kiln – Estimated Impacts of NOx Controls on Visibility 

at Wolf Island 

Control 

Technology 

Emissions 

(tpy) 

Removal 

Efficiency 

(%) 

Tons 

Removed

(tpy) 

Mm-1 per 

TPY* 

Extinction 

reduction 

(Mm-1) 

NOx Controls

. 

SCR 149.2 80 119.4 0.000013 0.0015 

Fuel switch to NG 149.2 73 108.9 0.000013 0.0014 

Low NOx burner 149.2 50 74.6 0.000013 0.0009 

SNCR - urea based 149.2 50 74.6 0.000013 0.0009 

SNCR - NH3 based 149.2 30 44.8 0.000013 0.0006 

Table 5.2. Interstate Paper Power Boiler – Estimated Impacts of SO2 and NOx Controls 

on Visibility at Wolf Island 

Control 

Technology 

Emissions 

(tpy) 

Removal 

Efficiency 

(%) 

Tons 

Removed

(tpy) 

Mm-1 per 

TPY* 

Extinction 

reduction 

(Mm-1) 

SO2 Controls

. 

Fuel Switch to NG 300.5 99 297.5 0.000076 0.0225 

Wet scrubber with 

caustic 

300.5 

90 270.5 

0.000076 

0.0204 

Spray dry scrubber 300.5 85 255.4 0.000076 0.0193 

Dry scrubber 300.5 65 195.3 0.000076 0.0147 

NOx Controls

. 

SCR 409.2 80 327.4 0.000013 0.0041 

Low NOx burner 

with FGR 

409.2 

60 245.5 

0.000013 

0.0031 

Low NOx burner 409.2 50 204.6 0.000013 0.0026 

SNCR 409.2 50 204.6 0.000013 0.0026 

Fuel switch to NG 409.2 13 53.2 0.000013 0.0007 

* The estimated light extinction benefit at Wolf Island associated with the reduction of one ton per year of 

emissions (SO2 or NOx) from the emissions unit. 

BART Determination – Interstate Paper 18
6.0 ENGINEERING ANALYSIS SUMMARY

Table 6.0 summarizes the technically and economically feasible options for the BARTeligible emission units. 

Table 6.0. Summary of BART Analysis, Interstate Paper 

Emission Unit Pollutant Existing Controls BART Options $/ton

Recovery Boiler PM10 Venturi Scrubber Venturi Scrubber 0 

Recovery Boiler NOx Staged Air Combustion Staged Air Combustion 0 

Recovery Boiler SO2 Combustion Control Combustion Control 0 

Lime Kiln PM10 Wet Scrubber Wet Scrubber 0 

Lime Kiln NOx Not Available None Applicable 0 

Lime Kiln SO2 Wet Scrubber Wet Scrubber 0 

Power Boiler PM10 Not Available Fuel Switch to natural gas 5,705 

Power Boiler NOx Not Available Fuel Switch to natural gas 29,800 

Power Boiler SO2 Not Available Fuel Switch to natural gas 370.00 

7.0 BART DETERMINATION VISIBILITY IMPACTS ASSESSMENT

In order to evaluate the potential visibility impacts or improvements at Class I areas 

which may be caused by the implementation of various emissions scenarios at the 

Interstate Paper mill, CALPUFF air dispersion modeling was conducted. Such modeling 

was conducted in accordance with the VISTAS Regional Planning Organization’s BART 

Modeling Protocol, version 3.2, dated August 31, 2006. The impacts of plant emissions 

were assessed under three emissions scenarios. The first scenario constitutes a baseline 

of emissions, based on actual plant emissions of visibility-affecting pollutants as 

determined from the facility’s 2002 worst-case (maximum) actual emissions over any 24-

hour period. The second scenario was evaluated on the basis that the facility’s Power 

BART Determination – Interstate Paper 19
Boiler would be shut-down, as initially proposed by the facility. The third scenario was 

assessed on the basis that the facility’s Power Boiler would operate on natural gas. 

The facility is located in Riceboro, Georgia. Three Class I areas are within 300 km of the 

site, the Cape Romain Wildlife Management Refuge (WMR), SC ( 207 km), the 

Okefenokee WMR, GA (109 km), and the Wolf Island WMR, GA (42 km). 

7.1 Baseline Emission Scenario 

On August 8, 2006, Interstate Paper, LLC submitted a facility-specific BART exemption 

modeling protocol to GA EPD. Review of this protocol indicated that the stack 

coordinates listed in the protocol did not compare favorably to coordinates for those 

stacks used in a 2001 Prevention of Significant Deterioration (PSD) permit application. 

The coordinates were modified, and the Building Profile Input Program (BPIPPRM, 

version 04274) was run to develop downwash dimensions. Downwash dimensions were 

required to be evaluated since the facility is located less than 50 km from the Wolf Island 

WMR and since the facility’s stacks are each less than Good Engineering Practice Stack 

Height (GEP). Also due to the facility’s location within 50 km of the Wolf Island WMR, 

4-km grid-based CALMET output files, prepared by the VISTAS contractor, were used 

in all the modeling. 

The mill’s emissions data was compiled by the mill’s consultant, Environmental 

Planning Specialists, Inc (EPS) from stack test, AP-42, and/or NCASI information. The 

specific data sources were submitted with the Interstate Paper, LLC BART Exemption 

Modeling Protocol prepared for the facility by EPS. The emission calculations were 

reviewed by GA EPD permit engineers (see attached Table 1., prepared by the VISTAS 

contractor). 

Each of the three International Paper BART-eligible emission sources were modeled 

separately in CALPUFF by the VISTAS contractor, for each model year. Other than 

point sources, no other emissions were modeled. Wet and dry deposition losses from the 

plumes were accounted for. Building downwash dimensions from BPIPPRM were 

provided, but conservatively, only the BPIP dimensions were assessed for downwash 

BART Determination – Interstate Paper 20
effects on plume concentrations. Table 2, prepared by the VISTAS contractor, notes that 

all PM10 and H2SO4 emissions were conservatively partitioned into organic condensable 

species, split equally by particle size class. This specific measure was implemented in 

POSTUTIL by the use of scaling factors. Pasquill-Gifford dispersion coefficients were 

used in the modeling, rather than basing the dispersion on coefficients developed from 

turbulence data. The meteorological grid was set equal in extent to the computational 

grid, and the cell size of each was 4 km sq. All source and receptor locations were 

assessed using the Lambert Conformal Conic coordinate system. 

CALPUFF modeling was conducted to provide concentrations at Class I area receptors 

located in the Cape Romain, SC; St. Marks, FL; Okefenokee, GA; and Wolf Island, GA 

Wildlife Management Refuges. Chemical transformation rates of SO2 and NOx into 

SO4

-2, HNO3, and NO3-1 were assessed using the MESOPUFF II scheme with hourly 

ozone concentrations derived from contemporaneous monitoring in the domain, and a 

constant (uniform) monthly average ammonia concentration of 0.5 ppb throughout the 

domain. 

POSTUTIL conversion of the CALPUFF concentration files was implemented to develop 

the PM10 (and H2SO4) emissions into two equal size fractions of PM2.5 condensable 

organic matter. The Ammonia-Limiting Method of limiting ammonium nitrate formation 

due to the scavenging of atmospheric ammonia to form ammonium sulfate, was not 

implemented in the POSTUTIL processing. The speciated emissions of each of the three 

modeled sources were summed, by species, at the Class I area receptors modeled. 

The CALPOST processor was implemented to assess, by Method 6, the 24-hour average 

change from annual average, natural background visibility caused by the facility’s 

sources, in delta-deciviews (ΔdV). The FLAG, 2000 proposed relative humidity 

function, with a maximum value of 95 %, was used to simulate hygoscopic species 

growth. Extinction coefficients of sulfate and nitrate (hygroscopic) species were 

computed using monthly relative humidity adjustment factors. The visibility calculations 

were made using the (original) IMPROVE equation. 

BART Determination – Interstate Paper 21
The results of the baseline visibility assessment of the Interstate Paper, LLC BARTeligible sources is presented in Tables 3 and 4, prepared by the VISTAS contractor. 

Table 3 indicates these sources to have no impact at either the St. Marks, FL, or the Cape 

Romain, SC WMRs. 

The expanded results shown in Table 4 indicate that, based on the highest 98th percentile 

change in visibility (one of the design criteria when modeling using a 4-km 

computational grid), the impacts of the Interstate Paper BART-eligible sources at the 

Okefenokee WMR are well below the BART exemption level of 0.5 ΔdV. The alternate 

design criteria when modeling with a 4-km computational grid is the highest 22nd high 

over the three years modeled. Table 4 indicates that the BART exemption level of 0.5 

ΔdV is met with the 11th highest impact over the three year period modeled at the 

Okefenokee WMR. This indicates that the Interstate Paper BART-eligible sources do not 

need to consider their impacts at the Okefenokee WMR further. 

However, the expanded results indicated on Table 4 for the Wolf Island WMR fail to 

meet the BART exemption criteria on both the annual and the 3-year period basis, by 

exceeding the exemption level with the 98th percentile impact in each of the three 

modeled years, as well as exceeding the 3-year period design criterion of 0.5 ΔdV with 

the 22nd highest impact. 

7.2 Proposed alternative exemption scenario #1. Interstate Paper proposed to 

shutdown its Power Boiler, which had by far the greatest impact on the visibility at Wolf 

Island. The Power Boiler was modeled as it operates, with no air pollution control 

equipment. The Power Boiler is permitted to burn #6 fuel oil containing as much as 3 wt. 

percent sulfur. The VISTAS contractor re-evaluated the remaining two Interstate BARTeligible sources, using the same modeling techniques as implemented in the baseline 

modeling. The results are indicated on Tables 5 and 6, prepared by the VISTAS 

contractor. These results show only two 24-hour periods were predicted to have visibility 

impacts in excess of the BART exemption level over the 3-year period modeled, and 

those impacts were limited to the Wolf Island WMR. Clearly this is a scenario which, if 

implemented by the facility, would exempt Interstate Paper from further BART 

requirements. However, Interstate Paper declined to pursue this alternative. 

BART Determination – Interstate Paper 22
7.3 Proposed alternative exemption scenario #2. The Georgia Environmental 

Protection Division (GA EPD) completed a BART Determination assessment of several 

alternative scenarios. Based on the detailed BART analysis of control options feasible 

for each of the BART-eligible sources, GA EPD determined that the most beneficial 

control option would be to limit the Power Boiler to burning natural gas. 

In developing appropriate emissions estimates for this scenario, it was noticed that the 

Power Boiler is permitted as a back-up device for controlling non-condensable gases 

(NCGs). The current Title V application list the SO2 emission rate due solely to 

combusting NCGs as 53.8 pounds of SO2 per hour, and includes a limit of such operation 

to 1480 hours per year. AP-42 was used to calculate the SO2 and NOx emission rates 

appropriate for firing the Power Boiler at 100% capacity. The AP-42 emission rate was 

increased by the maximum SO2 emissions due to combustion of NCGs in the Power 

Boiler. These emissions, indicated in Table 7 and 8, were modeled for this alternative 

scenario. The modeling was conducted in the same manner as the other two modeled 

scenarios. 

The results of modeling the natural gas combustion scenario are presented in Tables 9 

and 10. Only Wolf Island receptors were evaluated, since the other Class I areas had 

already been demonstrated to be unaffected by Interstate Paper emissions, or Interstate 

Paper was able to be exempted from further BART requirements in these other Class I 

areas. 

In contrast to the baseline scenario, the natural gas firing scenario showed a total of 14 

occurrences of impacts over 0.5 ΔdV at Wolf Island versus 30 occurrences in the baseline 

scenario. Thus the 3-yr period impacts decreased below the exemption level on this 

basis. In 2001, the number of 24-hr average exceedances of 0.5 ΔdV decreased from 8 to 

6 per year; in 2002, the number decreased from 12 to 6 per year; and in 2003, the number 

decreased from 10 to 2 per year. Since none of the modeled years in the natural gas 

firing scenario showed a 98th percentile high impact in excess of 0.5 ΔdV, the facility 

meets both exemption criteria by implementing this scenario. 

BART Determination – Interstate Paper 23
7.4 BART modeling results summary. The facility has been shown to conform to 

BART exemption criteria for visibility impacts under the Regional Haze Regulation in 

the scenario where the Power Boiler must burn natural gas (and in selected operational 

scenarios, NCGs). However, since the facility went through the BART Determination 

mechanism to achieve this status, the facility should not be allowed to burn #6 fuel oil in 

trade for periods in which NCGs are not combusted in the Power Boiler. The combustion 

of NCGs should be restricted to periods of emergency only, when the Lime Kiln (primary 

NCG control device) and the Multi-fuel Boiler (secondary NCG control device) are outof-service. Both the latter two sources have existing SO2 control devices on their exhaust 

streams, while the Power Boiler does not. 

BART Determination – Interstate Paper 24
BART Determination – Interstate Paper 

INTERSTATE PAPER, LLC 

Georgia 

Visibility Results for 2001-2003 CALPUFF Screening Runs 

CALPOST, Method 6 

Using annual average Haze Index (HI) values in processing 

Table 1. Stack parameters and emissions 

Lambert Conformal 

Stack Coordinates 

ID # LCC East LCC North 

Stack 

Height 

Base 

Elevation Diameter Gas Exit Velocity 

Stack 

Gas 

Exit 

Temp. 

SO2

Emissions 

SO4

Emissions 

NOx

Emissions 

PM

Emis

km km m m m m/s K g/s g/s g/s g

PB 1470.712 -789.031 46.04 4.30 1.98 15.45 470.92 60.5000 0.0000 8.7000 3.4

LK 1470.714 -788.897 15.24 3.60 1.52 4.96 342.09 0.1600 0.0000 2.2000 0.74RB 1470.714 -789.026 46.04 4.20 2.74 13.73 353.37 0.1200 0.0000 8.8000 5.5

Table 2. Particle Speciation 

particle speciation Condensable Filterable Stack ID 

# filterable 

PM10

condensa

ble PM10

organic 

condensable (OC) 

inorganic 

condensable COARSE Soil 

% % 

0.625-

1.0 

μm 

(g/s) 

0.5-

0.625 

μm 

(g/s) 

0.625-

1.0 

μm 

(g/s) 

0.5-

0.625 

μm 

(g/s) 

6-10 

μm 

(g/s) 

2.5-6 

μm 

(g/s) 

1.25-

2.5 

μm 

(g/s) 

1.0-

1.25 

μm 

(g/s) 

0.625-

1.0 

μm 

(g/s) 

0.5-

0.625 

μm 

(g/s) 

1.

2

μ

(g

PB 1.7000 1.7000 

LK 0.3700 0.3700 RB 2.7500 2.7500 

Note: Stack parameters and emission data obtained from “EPD BART Emissions.xls” file. The PM speciation was not provided by the state. All PM10 - H2S

between the two size categories of OC. This is a conservative approach since, Organic condensable have extinction efficiency of 4 m2/g. 
BART Determination – Interstate Paper 

Table 3. Summary of Visibility Results 

Class I Area 2001 2002 2003 

Annual 

average 

background 

bext

Maximum delta-deciview, (# days>0.5 dv, # days >1 dv) (Mm-1) 

Cape Romain 0.330 (0 0) 0.408 (0 0) 0.242 (0 0) 21.22 

Okefenokee 0.670 (4 0) 0.561 (3 0) 1.153 (4 1) 21.41 

St Marks 0.192 (0 0) 0.196 (0 0) 0.247 (0 0) 21.54 

Wolf Island 1.653 (8 1) 0.963 (12 0) 0.938 (10 0) 21.33 

Table 4. Visibility Results – 8 highest values 

2001 2002 2003 

Change in 

Deciview (dv) Day Change in Deciview (dv) Day Change in Deciview (dv) Day 

Okefenokee 

0.670 0.579 0.520 0.514 0.431 0.431 0.431 0.318 

Feb 13 

Nov 19 

Oct 22 

Dec 4 

Jun 20 

Feb 12 

Jan 14 

Oct 23 

0.561 0.516 0.500 0.462 0.461 0.456 0.401 0.338 

Dec 8 

Oct 22 

Jan 27 

Oct 25 

Dec 18 

Jan 26 

Oct 14 

Feb 3 

1.153 0.630 0.523 0.500 0.391 0.341 0.336 0.328 

Jan 31 

Dec 27 

Nov 8 

Sep 10 

Nov 21 

Oct 31 

Jan 28 

Nov 11 

Wolf Island 

1.653 0.851 0.759 0.755 0.675 0.665 0.584 0.573 

Jan 15 

Sep 17 

Jan 10 

Feb 6 

Jan 21 

Sep 9 

Sep 18 

Dec 21 

0.963 0.962 0.943 0.823 0.751 0.731 0.691 0.650 

Jan 28 

Dec 27 

Nov 26 

Sep 17 

Nov 1 

Dec 30 

Jan 16 

Oct 26 

0.938 0.763 0.760 0.707 0.630 0.609 0.574 0.565 

Dec 8 

Sep 7 Sep 8 

Jul 15 

Nov 22 

Oct 15 

Oct 4 

Nov 7 
BART Determination – Interstate Paper 

Table 5. Summary of Visibility Results 

Class I Area 2001 2002 2003 

Annual 

average 

background 

bext

Maximum delta-deciview, (# days>0.5 dv, # days >1 dv) (Mm-1) 

Cape Romain 0.069 (0 0) 0.106 (0 0) 0.048 (0 0) 21.22 

Okefenokee 0.236 (0 0) 0.187 (0 0) 0.337 (0 0) 21.41 

St Marks 0.034 (0 0) 0.041 (0 0) 0.045 (0 0) 21.54 

Wolf Island 0.718 (1 0) 0.502 (1 0) 0.416 (0 0) 21.33 

Table 6. Visibility Results – 8 highest values 

2001 2002 2003 

Change in 

Deciview (dv) Day Change in Deciview (dv) Day Change in Deciview (dv) Day 

Wolf Island 

0.718 0.371 0.345 0.312 0.310 0.282 0.231 0.216 

Jan 15 

Sep 17 

Jan 10 

Feb 6 

Dec 21 

Jan 21 

Dec 30 

Jan 2 

0.502 0.420 0.357 0.337 0.311 0.286 0.273 0.241 

Dec 27 

Nov 26 

Nov 1 

Jan 16 

Nov 19 

Dec 26 

Oct 26 

Jan 28 

0.416 0.335 0.268 0.265 0.257 0.255 0.250 0.189 

Dec 8 

Oct 15 

Sep 7 

Nov 30 

Sep 8 

Jan 7 Jan 5 

Feb 9 
BART Determination – Interstate Paper 

INTERSTATE PAPER, LLC 

Georgia 

Visibility Results for 2001-2003 CALPUFF Screening Runs 

CALPOST, Method 6 

Using annual average Haze Index (HI) values in processing 

Table 7. Stack parameters and emissions 

Lambert Conformal 

Stack Coordinates 

ID # LCC East LCC North 

Stack 

Height 

Base 

Elevation Diameter Gas Exit Velocity 

Stack 

Gas 

Exit 

Temp. 

SO2

Emissions 

SO4

Emissions 

NOx

Emissions 

PM

Emis

km km m m m m/s K g/s g/s g/s g

PB 1470.712 -789.031 46.04 4.30 1.98 15.45 470.92 60.5000 0.0000 8.7000 3.4

LK 1470.714 -788.897 15.24 3.60 1.52 4.96 342.09 0.1600 0.0000 2.2000 0.74RB 1470.714 -789.026 46.04 4.20 2.74 13.73 353.37 0.1200 0.0000 8.8000 5.5

PB* 1470.712 -789.031 46.04 4.30 1.98 15.45 470.92 6.81 0.0000 13.83 3.4

Table 8. Particle Speciation 

particle speciation Condensable Filterable Stack ID 

# filterable 

PM10

condensa

ble PM10

organic 

condensable (OC) 

inorganic 

condensable COARSE Soil 

% % 

0.625-

1.0 

μm 

(g/s) 

0.5-

0.625 

μm 

(g/s) 

0.625-

1.0 

μm 

(g/s) 

0.5-

0.625 

μm 

(g/s) 

6-10 

μm 

(g/s) 

2.5-6 

μm 

(g/s) 

1.25-

2.5 

μm 

(g/s) 

1.0-

1.25 

μm 

(g/s) 

0.625-

1.0 

μm 

(g/s) 

0.5-

0.625 

μm 

(g/s) 

1.

2

μ

(g

PB 1.7000 1.7000 

LK 0.3700 0.3700 RB 2.7500 2.7500 

PB* 1.7000 1.7000 

Note: Stack parameters and emission data obtained from “EPD BART Emissions.xls” file. The PM speciation was not provided by the state. All PM10 - H2S

between the two size categories of OC. This is a conservative approach since, Organic condensable have extinction efficiency of 4 m2/g. 

 * Power Boiler as modified by GA EPD for Determination modeling to ONLY Wolf Island. Natural gas PTE includes ability to combust non-conden
BART Determination – Interstate Paper 

Table 9. Summary of Visibility Results 

Class I Area 2001 2002 2003 

Annual 

average 

background 

bext

Maximum delta-deciview, (# days>0.5 dv, # days >1 dv) (Mm-1) 

Cape Romain 0.330 (0 0) 0.408 (0 0) 0.242 (0 0) 21.22 

Okefenokee 0.670 (4 0) 0.561 (3 0) 1.153 (4 1) 21.41 

St Marks 0.192 (0 0) 0.196 (0 0) 0.247 (0 0) 21.54 

Wolf Island 1.653 (8 1) 0.963 (12 0) 0.938 (10 0) 21.33 

Wolf Island* 1.380 (6 1) 0.873 ( 6 0) 0.773 ( 2 0) 21.33 
BART Determination – Interstate Paper 

Table 10. Visibility Results – 8 highest values (asterisked values (*) indicate GA EPD Determination modeling 

 Bold format concentrations are >0.5Dv, Bold format dates are different or in different sequence from date

2001 2002 2003 

Chg. in 

Deciview 

(dv)

Day

Chg. in 

Deciview 

(dv)

Day

Chg. in 

Deciview 

(dv)

Day 

Okefenokee 

0.670 0.579 0.520 0.514 0.431 0.431 0.431 0.318 

Feb 13 

Nov 19 

Oct 22 

Dec 4 

Jun 20 

Feb 12 

Jan 14 

Oct 23 

0.561 0.516 0.5000.462 0.461 0.456 0.401 0.338 

Dec 8 

Oct 22 

Jan 27 

Oct 25 

Dec 18 

Jan 26 

Oct 14 

Feb 3 

1.153 0.630 0.523 0.500 0.391 0.341 0.336 0.328 

Jan 31 

Dec 27 

Nov 8 

Sep 10 

Nov 21 

Oct 31 

Jan 28 

Nov 11 

Wolf Island 

1.653 0.851 0.759 0.755 0.675 0.665 0.584 0.573 

Jan 15 

Sep 17 

Jan 10 

Feb 6 

Jan 21 

Sep 9 

Sep 18 

Dec 21 

1.380*0.614*0.604*0.559*0.547*0.525*0.396* 0.336* 

Jan 15 

Sep 17 

Jan 10 

Feb 6 

Jan 21 

Dec 21 Dec 30 

Jan 2

0.963 0.962 0.943 0.823 0.751 0.731 0.691 0.650 

Jan 28 

Dec 27 

Nov 26 

Sep 17 

Nov 1 

Dec 30 

Jan 16 

Oct 26 

0.873* 0.786* 0.604* 0.583* 0.548* 0.501*0.482* 0.457* 

Jan 28 

Dec 27 

Nov 26 

Sep 17 

Nov 1 

Dec 30 

Jan 16 

Oct 26 

0.938 0.763 0.760 0.707 0.630 0.609 0.574 0.565 

Dec 8 

Sep 7 Sep 8 

Jul 15 

Nov 22 

Oct 15 

Oct 4 

Nov 7 

0.773*0.529*0.463* 0.454* 0.440* 0.438* 0.420* 0.339* 
BART Determination – Interstate Paper 31

APPENDIX A 

Impacts of SO2, NOx, and Primary Carbon (PC) on Okefenokee and Wolf Island Class I Areas 
Emission sensitivities were performed by Georgia Tech to examine the impact of SO2, NOx, and primary carbon 

(PC) on Okefenokee and Wolf Island Class I areas. The impacts (Mm-1) were normalized by the emissions 

(tons/year) to show the relative importance of SO2, NOx and PC emission reductions by source category and by 

state (Figures A-1 and A-2). Figures A-3 and A-4 contain the normalized visibility responses on 20% worst days 

at Okefenokee and Wolf Island to reductions from the 2009 BaseD inventory for non-EGU point SO2 emissions 

and point NOx emissions in Georgia. 

At Okefenokee, the light extinction impact due to one ton of non-EGU SO2 is 2.59E-05 Mm-1/TPY and the light 

extinction impact due to one ton of point NOx is 0.159E-05 Mm-1/TPY. Therefore, the reduction of one ton of 

SO2 emissions is 16.4 times more efficient than the reduction of one ton of NOx emissions at Okefenokee. 

At Wolf Island, the light extinction impact due to one ton of non-EGU SO2 is 1.97E-05 Mm-1/TPY and the light 

extinction impact due to one ton of point NOx is 0.319E-05 Mm-1/TPY. Therefore, the reduction of one ton of 

SO2 emissions is 6.2 times more efficient than the reduction of one ton of NOx emissions at Wolf Island. 

Okefenokee, GA (Worst)

-0.00018

-0.00015

-0.00012

-0.00009

-0.00006

-0.00003

0.00000

SO2_EGU

SO2_nonEGU

NOx_Ground

NOx_Point

PC_Ground

PC_Point

Δ

Bext /ΔE (Mm-1/TPY)

WV

VA

TN

SC

NC

MS

KY

GA

FL

AL

Figure A-1: CMAQ projections of normalized visibility responses on 20% worst days at Okefenokee, GA to 

reductions from the 2009 BaseD inventory for visibility-reducing pollutants in different source categories and 

geographic areas. 

BART Determination – Interstate Paper 32
Wolf_Island, GA (Worst)

-0.00010

-0.00008

-0.00006

-0.00004

-0.00002

0.00000

SO2_EGU

SO2_nonEGU

NOx_Ground

NOx_Point

PC_Ground

PC_Point

Δ

Bext /ΔE (Mm-1/TPY)

WV

VA

TN

SC

NC

MS

KY

GA

FL

AL

Figure A-2: CMAQ projections of normalized visibility responses on 20% worst days at Wolf Island, GA to 

reductions from the 2009 BaseD inventory for visibility-reducing pollutants in different source categories and 

geographic areas. 

Okefenokee, GA (Worst)

-0.000030

-0.000025

-0.000020

-0.000015

-0.000010

-0.000005

0.000000

SO2_nonEGU NOx_Point

Δ

Bext /ΔE (Mm-1/TPY)

GA

Figure A-3: CMAQ projections of normalized visibility responses on 20% worst days at Okefenokee, GA to 

reductions from the 2009 BaseD inventory for non-EGU point SO2 emissions and point NOx emissions in 

Georgia. 

BART Determination – Interstate Paper 33
Wolf_Island, GA (Worst)

-0.000025

-0.000020

-0.000015

-0.000010

-0.000005

0.000000

SO2_nonEGU NOx_Point

Δ

Bext /ΔE (Mm-1/TPY)

GA

Figure A-4: CMAQ projections of normalized visibility responses on 20% worst days at Wolf Island, GA to 

reductions from the 2009 BaseD inventory for non-EGU point SO2 emissions and point NOx emissions in 

Georgia. 

BART Determination – Interstate Paper 34