STGEL 900 SW Fifth Avenue. SUlle 2600

Portland. Oregon 97204 

main 503.224 JJ80 

~~,~ fax 503 220 2480 

1A'\\oW.~loel.com

ATTORNEYS AT LAW 

THOMAS R. WOOD 

Direct (503) 294-9396 

October 5, 2011	 trwood@stoel.com 

U.S Environmental Protection Agency Region 8
 

1595 Wynkoop St.
 

Denver, CO 80202-1129
 

Attention: Vanessa Hinkle, 8P-AR
 

Re:	 Response to Request for Additional Information for Montana City BART 

Determination 

Dear Vanessa: 

On September 19,2011, Ash Grove Cement Company ("Ash Grove") received by mail your 

information request made pursuant to Section 114 of the Clean Air Act and requesting 

information for use in determining Best Available Retrofit Technology ("BART") for the 

Montana City facility. Specifically, you requested that Ash Grove document that wet scrubbing 

is not technically feasible and that Ash Grove submit a five factor analysis of dry scrubbing 

techniques. This submittal was requested to be submitted by September 30, 2011-9 working 

days after receipt of the 114 request by mail. As I communicated to you, Ash Grove believes 

that this is an unreasonable amount of time to allow for response to such a significant request. A 

complete 5 factor analysis cannot be performed in 9 days. However, Ash Grove committed to do 

the best it could do within the time frame allowed. This letter constitutes Ash Grove's response 

to this request. 

I.	 Confidential Business Information 

Ash Grove is claiming confidential business information ("CBI") status for the information 

provided in this 114 response. This information complies with 40 CFR §§ 2.203(b) and 2.301 as 

well as Montana law. The identified information is eligible for CBI treatment under 40 CFR 

§ 2.208 for the following reasons: (a) this claim of confidentiality has not expired by its own 

terms, been withdrawn, or waived; (b) Ash Grove does not release information claimed as CBI to 

non-employees; only limited authorized employees have access to the financial information and 

production information claimed as CBI; Ash Grove intends to continue to keep internal 

distribution of this material limited and external distribution of this material prohibited; (c) the 

information is not obtainable without Ash Grove's consent; (d) there is no statutory obligation to 

disclose this information; and (e) disclosure of this information would harm Ash Grove's 

competitive position by making capital investment, cost of production, and operating 

information, not otherwise available, potentially known to Ash Grove's competitors. 

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The cement business is intensely competitive as manufacturers compete for shares in a limited 

market. The market is increasingly threatened by the import of overseas products and by new 

competitors. Consequently, information related to production, operation, performance, cost, 

pricing, and value, if disclosed to competitors can reveal critical data regarding Ash Grove's 

ability to compete in the market. 

II. Background 

Ash Grove's Montana City kiln is a long wet kiln that has been in operation since 1963. The kiln 

currently employs an electrostatic precipitator ("ESP") for the control of particulate ("PM"), 

good combustion practices and burner pipe maintenance/position for NOx control and inherent 

scrubbing and the use oflow sulfur coal as a component of the fuel mix for S02 control. As was 

previously described in Ash Grove's February 28, 2008 letter to Ms. Callie Videtich, a mass 

balance of sulfur inputs and emissions indicate that in 2006 the inherent dry scrubbing achieved 

by the kiln design resulted in 80 percent control of S02. Although inlet/outlet testing has not 

been performed, the kiln ESP would be expected to achieve 95 to 99 percent control. The PM 

emissions from the clinker cooler are controlled by a baghouse. Although inlet/outlet testing has 

not been performed, the clinker cooler baghouse would be expected to achieve 99 percent 

control. 

III. Response to Questions 

Ash Grove has undertaken to respond to EPA's request to the best of its ability. Ash Grove 

reserves all objections to this information request and the obviously inability of the company to 

respond to a request of this magnitude in the time provided. In your September 9,2011 letter, 

you posed two questions. Each of those questions is reproduced below in italics and the 

response follows. 

Request No 1: Support your statement that wet scrubbing is not technically feasible. 

In my letter of July 18,2011, I explained that wet scrubbers are no longer a technically feasible 

control for consideration as BART technology for the Montana City kiln. As explained in 

further detail below, this conclusion was based on an analysis performed consistent with EPA's 

guidance in the July 6, 2005 BART guidelines. 

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In a BART analysis data are collected through a five step process to arrive at a selection ofthe 

best methods of emissions reduction ofNOx, S02, and PM at the BART source. The five steps 

followed to develop information for making the BART determination are the following: 

1. Identify all available retrofit control technologies. 

2. Eliminate technically infeasible options. 

3. Evaluate control effectiveness of remaining control technologies. 

4. Evaluate impacts and document the results. 

5. Evaluate visibility impacts. 

These steps generate data that are used to evaluate the costs and benefits of various control 

technologies and, ultimately, identify the retrofit technology appropriate for installation at the 

source. 

Step 2 of the BART analysis involves the evaluation of all the identified available retrofit control 

technologies to determine technical feasibility. A control technology is technically feasible if it 

has been previously installed and operated successfully at a similar type of source or ifthere is 

technical agreement that the technology can be applied to the source. Two terms, "available" 

and "applicable," are used to define the technical feasibility of a control technology. A 

technology that is being offered commercially by vendors or is in commercial demonstration or 

licensing is generally deemed an available technology. Technologies that are in development 

and testing stages are classified as not available. Similarly, unless a technology can be 

demonstrated to comply with all applicable requirements, it cannot be considered available. The 

fact that a technology might be considered available is not a sufficient basis for concluding that a 

technology is applicable, and, therefore, technically feasible. A commercially available 

technology must also be "applicable," i.e., it must have been previously installed and operated at 

a similar type of source or a source with similar gas stream characteristics. Unless the 

technology is identified as both available and applicable, the technology is not considered 

technically feasible and, therefore, is not carried into Step 3 of the BART analysis process. 

Wet scrubbing is no longer an "available" control technology for wet cement kilns. As part of 

the February 28,2008 BART submittal, Ash Grove included a proposal from MECS for its 

Dynawave Scrubbing System. At that time, wet scrubbing was considered technically feasible 

for a wet kiln such as the one employed at Ash Grove's Montana City plant. The MECS 

proposal was dated April 27, 2007 and thus predated by several years the imposition of stringent 

new and existing source PM limits for cement kilns. At that time, the other primary supplier of 

wet scrubbing technology to the cement industry was Solios. Since the 2007 proposal was 

issued, EPA has imposed stringent new PM requirements. Specifically, the revised NESHAP 

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PM limit for existing kilns is 0.04lb/ton clinker and the limit for new kilns is 0.01 lb/ton clinker. 

The revised NSPS limit for new, modified or reconstructed kilns is also 0.01 lb/ton clinker. 

Since these standards were issued, Solios withdrew from the market, now being unwilling to 

guarantee that their wet scrubbing technology will meet the cement NSPS and NESHAP PM 

limits. Similarly, MECS will not guarantee that its Dynawave technology will meet the NSPS 

and new source NESHAP limits. The total capital cost of installing a wet scrubber (based on a 

2010 MECS proposal) is slightly more than $30 million (see attached cost-effectiveness analysis 

for costing details). Ash Grove could not be re:llistically expected to install a $30 million control 

system on a 50 year old kiln without upgrading the kiln to maximize its output. Such a capital 

outlay would not be justified under any circumstances, but certainly not where the kiln is 

operating at its current levels. If EPA requires installation of a $30 million wet scrubber, the 

result will either be plant closure or reconstruction of the kiln. Reconstruction ofthe kiln would 

necessarily trigger NSPS and the 0.01 lb/ton clinker PM standard which the wet scrubber 

manufacturers will not guarantee that a wet scrubber can meet. Because a wet scrubber is not 

available, as that tenn is used in the BART gllidelines, the technology cannot be considered 

technically feasible. 

Wet scrubbing is also not an applicable technology for a wet kiln such as Ash Grove's Montana 

City kiln. The Montana City kiln is a long wet kiln. Although there are 5 kilns in the U.S. that 

are using wet scrubbers to control S02 emissions, none ofthese kilns are wet kilns. Each ofthe 

5 kilns is a preheater/precalciner kiln. There is no basis for assuming that the technology 

employed on a preheater/precalciner kiln will be transferrable over to a long wet kiln without 

extensive experimentation and pilot studies to detennine how the equipment must be modified to 

meet the PM standards. Therefore, wet scrubbing is not applicable, as that tenn is used in the 

BART guidelines, and so cannot be considered technically feasible. 

Ash Grove perfonned an independent analysis ofthe limited data available on those few kilns 

where wet scrubbers have been installed in order to verify the PM compliance issue. As noted 

above, the 5 kilns in the U.S. using wet scrubbers to control S02 emissions are all 

preheater/preca1ciner kilns while the Montana City kiln is a long wet kiln. The significantly 

different exhaust gas characteristics between a preheater/precalciner kiln and a long wet kiln are, 

in part, responsible for the technology not being directly transferrable. For example, the air flow 

Through a wet kiln is roughly twice that of a dry kiln on a dscf/ton feed basis. However, even if 

those differences are disregarded, the evidence indicates that a wet scrubber will increase 

filterable particulate matter emissions to a pOl:~! that the plant will be unable to consistently meet 

the existing source NESHAP PM emission limit of 0.04 lbs/ton of clinker, let alone the new 

source emission PM limit (NSPS and NESHAP) of 0.01 lbs/ton of clinker. This conclusion is 

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based on the data Ash Grove collected and assessed of PM emission tests for four of the five 

kilns to determine the expected PM emissions from a wet scrubber on a cement kiln. 

As EPA has previously recognized, in order to accurately predict long term performance, it is 

necessary to take into account the variability tllat occurs test-to-test as well as run-to-run. EPA 

has long understood that it must employ statistical methodologies to address the need to account 

for variability in developing emission limits that accurately represent the ability of a source to 

perform over an extended period of time. For example, EPA stated in the preamble to the 

Hazardous Waste Combustor ("HWC") NESHAP that "sources which are lowest emitting in 

single emission tests may not be the lowest emitters over time due to their test-to-test 

variability." 72 Fed. Reg. 54875,54878 (Sept. 27, 2007). Later in the HWC NESHAP, EPA 

discussed the issue of variability for controls other than fabric filters ("FF"): 

Sources equipped with control devices other than FFs are likely to 

emit more over time than they do in individual test conditions, even 

after adjusting test results to account for run-to-run variability. (Put 

another way, these sources' performance in individual test conditions 

are likely not representative of what they will emit over time.) This is 

because test-to-test variability, that is, long-term variability, has not 

been taken into account. Since these other control devices are known 

to be more variable and less efficient than FFs, TSD Vol. III pp. 16-3 

to 4 and 11, failure to consider long-term variability (i.e., looking 

exclusively at results of single performance tests) results in these 

sources' performance not being fully characterized. Long-term 

variability exists due to, among other things, variation over time in 

control device performance and varying ash feed rates. EPA 

confirmed in a series of analyses ofHWCs that this test-to-test 

variability for non-FF equipped devices both exists and is 

appreciable. Id at 54878-79. 

This same issue of variability and the need to account for it was discussed extensively in the PC 

NESHAP. In that context, EPA stated that it sought to define the NESHAP limits based on the 

use of available data such that if they were to randomly select a future test from any of the 

sources, they would be 99 percent confident that the future value would fall below the 

established limit. 75 Fed. Reg. 54969, 54975 (Sept. 9,2010). 

Although Ash Grove does not necessarily agree that EPA's approach is a fair method to use to 

set enforceable limits monitored using CEMs, Ash Grove applied a similar methodology to 

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evaluate how the wet scrubber controlled kilns would perfonn. First, in order to nonnalize 

results and employ the available data, it was necessary to detennine what grain loading would be 

necessary in order to achieve the existing source PM standard of 0.04 lbs/ton of clinker. This 

was detennined by taking the actual flow rate and production levels during several source tests 

perfonned at the Montana City kiln. This gives the infonnation necessary to convert the lbs/ton 

clinker limit to a gr/dscf limit. 

Table 1: Montana City Kiln 

Date of Test 

Run 

Flow Rate 

(dscfm) 

Production 

Rate 

(TPH) 

dscfhon 

clinker 

MACT 

Limitpounds per 

ton of clinker 

MACT Limit 

- Grains per 

ton of clinker 

Grains per 

dscfto meet 

theMACT 

Limit during 

this stack 

test 

91712010 56649 38.8 87601.5 0.04 280 0.00320 

9/7/2010 61164 38.9 94340.4 0.04 280 0.00297 

91712010 64547 39.0 99303.1 0.04 280 0.00282 

9/8/2010 58938 38.8 91141.2 0.04 280 0.00307 

9/8/2010 60382 38.9 93134.2 0.04 280 0.00301 

9/8/2010 56870 38.9 87717.2 0.04 280 0.00319 

10/7/2009 57471 39.3 87742.0 0.04 280 0.00319 

101712009 58772 39.3 89728.2 0.04 280 0.00312 

10/7/2009 57682 39.3 88064.1 0.04 280 0.00318 

Average 0.00308 

STDev 0.00013 

95% 

Percentile 

(low) 0.00287 

95% 

Percentile 

(high) 0.00330 

Minimum 0.00281 

In evaluating the results of this conversion, Ash Grove applied a 90 percent confidence interval 

by adding 1.65 standard deviations ("STDev") ~o the average of the data set. Because a 90 

percent confidence interval means that there is a 90 percent likelihood that a value will not lie 

above or below the data set, this means that if EPA sets a limit equal to the 90 percent confidence 

interval, they would predict that 5 percent of future test values would fall outside of each end of 

the range. As this test is not as rigorous as the one defined by EPA in the PC NESHAP, ifthe 90 

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percent confidence interval generates a value equal to or greater than the regulatory limit, the 

kiln in questions would not be deemed compliant. 

Ash Grove found one stack test for the Holcim kiln located in Florence, Colorado. This 

preheater/precalciner kiln employs a wet scrubber to control S02 emissions and there is a 

baghouse upstream ofthe wet scrubber. The PM emission rate from this single test was 0.0020 

gr/dscf. While this might suggest that a wet scrubber controlled kiln could comply with the 

range of grain loading limits necessary to achieve compliance with the existing source standard 

at Montana City, more comprehensive testing at other kilns with wet scrubbers paints a very 

different picture. 

Ash Grove found two stack tests for the TXI kiln located in Midlothian, Texas. This preheater/ 

precalciner kiln employs a wet scrubber to control S02 emissions and has a baghouse upstream 

of the wet scrubber. The results of each of the runs for these two stack tests are presented in 

Table 2. 

Table 2: TXI: Midlothian, TX 

Date Test Runs #/hr gr/dscf bws 02 T stack (F) 

9/26/2006 8:30 to 9:37 12.15 0.0027 0.180 12.4 286 

9/26/2006 13:38 to 14:47 10.3 0.0023 0.187 11.6 283 

9/29/2006 8:07to9:13 7.67 0.0017 0.183 11.6 280 

9/28/2006 6:35 to 7:51 16.45 0.0040 0.181 11.4 272 

9/28/2006 10:20 to 11 :28 8.54 0.0020 0.185 11.8 278 

9/28/2006 14:02 to 15:08 18.8 0.0046 0.186 10.4 272 

Average 12.31833 0.0029 

STDev 0.0012 

95% Percentile 0.0048 

These data from the TXI Midlothian kiln show that the 95th percentile grain loading based on 

these six test runs would be 0.0048 gr/dscf. This is well above the upper bound 95th percentile 

that would be required to be in compliance with the existing source PM standard at Ash Grove's 

Montana City kiln. Similarly, the 95th percentile value required to meet the existing source PM 

standard at Ash Grove's Montana City kiln is 0.0033 gr/dscf. The 95th percentile value for 

TXI's Midlothian kiln is significantly higher than that ofthe 95th percentile value at the 

Montana City kiln and the average value for the TXI kiln is only slightly lower that the average 

Montana City compliant value. This indicates that with a scrubber downstream of a baghouse, 

Ash Grove's Montana City kiln would be expected to violate the existing source PM standard a 

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significant amount of the time. This is not consistent with EPA's stated target of being 99 

percent confident that future values would fall below the established limit. 

Data from nine stack tests for the Hokim Kiln 1 located in Midlothian, Texas further bear out 

this trend. Hokim Kiln 1 is a preheater/ precalciner kiln that employs a wet scrubber to control 

S02 emissions with an upstream baghouse to control particulate. The results of those stack tests 

are presented in Table 3. 

Table 3: Holcim Kiln No.1; Midlothian, TX 

Test Date #/hr gr/dscf bws 02 T stack (F) 

10/9-10/2000 13.21 0.0056 0.188 12.4 137 

10/11-13/2000 16.15 0.0074 0.196 13.2 139 

6/24-25/2002 8.64 0.0034 0.192 12.2 138 

6/25-26/2002 15.90 0.0062 0.184 11.7 139 

1113/2004 5.53 0.0020 0.180 14.2 135 

1114/2004 17.00 0.0062 0.192 12.6 138 

3/14/2007 3.91 0.0015 0.172 13.2 133 

3/15/2007 11.82 0.0057 0.206 11.1 141 

8/25/2008 11.10 0.0042 0.218 12.5 146 

Average 11.47 0.0047 

STDev 0.0020 

95th Percentile 0.008 

As can be seen from this set of source tests, the average grain loading at Holcim's Kiln No.1 is 

well in excess of the upper bound 95th percentile value of grain loadings that would demonstrate 

compliance with the existing source PM standard at Ash Grove's Montana City. As with the 

TXI kiln data, the Hokim Kiln No.1 data indicate that using a wet scrubber downstream from a 

baghouse would result in Ash Grove's Montana City kiln exceeding the existing source PM 

standard considerably more than 50 percent 01 the time. 

This is again demonstrated when examining the data from Hokim Kiln No.2 in Midlothian, TX. 

Ash Grove obtained sixteen stack tests for the Holcim Kiln 2, thus providing a very robust data 

set. As with the other kilns examined, this preheater/ precalciner kiln employs a wet scrubber to 

control S02 emissions with a baghouse upstream of the scrubber. The results of the stack tests 

from Hokim Kiln No.2 are shown in Table 4. 

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Table 4: Holcim Kiln No.2; Midlothian, TX 

Test Date #/hr gr/dscf bws 02 T stack (F) 

12/4-5/2000 11.75 0.0046 0.189 12.9 141 

1/3-4/2001 15.85 0.0069 0.182 12.9 145 

6/24-25/2002 3.75 0.0014 0.207 13.0 142 

6/25-27/2002 5.97 0.0021 0.207 12.7 142 

8/26/2003 15.30 0.0057 0.195 10.3 139 

11/4/2004 1.06 0.0016 0.188 13.3 137 

11/3/2004 9.20 0.0035 0.175 13.5 135 

2/28 -3/02/2007 6.36 0.0022 0.168 12.2 134 

2/28 -3/01/2007 8.09 0.0031 0.174 11.6 136 

8/28/2008 18.30 0.0062 0.195 12.8 146 

7/30/2009 16.00 0.0056 0.189 13.0 138.7 

7/30-31/2009 8.60 0.0031 0.208 12.3 141.4 

7/21/2010 4.80 0.0017 0.178 13.0 144.5 

7/20/2010 9.00 0.0033 0.184 12.8 137.2 

11/9/2010 1.14 0.0004 0.164 13.2 135 

11/9-11/2010 2.75 0.0011 0.169 12.6 135 

Average 8.62 0.0033 

STDev 0.0020 

95th Percentile 0.0066 

Again, as with all of the tests except the single test on the Florence kiln, these data clearly show 

that a kiln with a wet scrubber, even one with a baghouse upstream of that scrubber, cannot 

reliably meet the existing source NESHAP PM limit. The average value for all of these tests is 

0.0033 gr/dscf--exactly equal to the upper bound 95th percentile for the range of grain loadings 

predicted to meet the existing source PM standard at the Montana City kiln. Thus, these data 

indicate that were the Montana City kiln to employ a wet scrubber, it would be expected to 

exceed the existing source PM standard approximately half ofthe time. 

No stack tests were found for the Lehigh Davenport kiln. 

These stack test results provide a compelling basis for concluding that if the Montana City 

cement kiln employs a wet scrubber, it cannot reliably meet the existing source NESHAP PM 

limit. The data summarized above demonstrate that a kiln with a wet scrubber would at best 

meet the PM standard only about half of the time. However, the NESHAP requires that kilns 

demonstrate continuous compliance utilizing a PM CEM. Given the available data, one cannot 

conclude that compliance with the existing source PM limit can be consistently demonstrated 

when a PM CEM is employed. This explains why one leading manufacturer of wet scrubbers for 

the cement industry is no longer selling wet scrubbers for cement kilns and the other primary 

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manufacturer will no longer provide written guarantees that the equipment will meet the 

standard. In light of the test data and the lack of confidence of the manufacturers that their wet 

scrubbing equipment can meet the existing source PM standard (let alone the standard that would 

apply if Ash Grove were to reconstruct its kiln) there is no basis on which to conclude that wet 

scrubbing is currently technically feasible. EPA cannot consider a control technology to be 

technically feasible if those controls are unlikely to be capable of operation without causing the 

Montana City plant to exceed the existing source PC NESHAP PM standard. 

In addition to the technical feasibility issues associated with the inability of the Montana City 

kiln to comply with the PC NESHAP and NSPS PM standards, wet scrubbing is also technically 

infeasible due to the lack of available water to operate the scrubber. Since the 2007 BART 

analysis was prepared, the State of Montana has decreased the water right held by Ash Grove's 

Montana City plant to match historical use. As a result, a considerable amount of the water for 

which the plant previously held a water right, has now been withdrawn by the State. The 

Montana City plant is in an area that only receives 11.9 inches of water per year. In such an 

area, water is an extremely valuable commodity. Because ofthe overappropriation of water 

rights, the State has become increasingly active in trimming existing water rights to match 

historic use. This is what occurred to Ash Grove. A wet scrubber is anticipated to consume 

approximately 38 gallons/minute of water, a total of approximately 19 million gallons/yr (~61

acre-ft/year). EPA cannot require Ash Grove to install and operate such a technology in an arid 

part of the country where there is no certainty that Ash Grove would even be able to obtain a 61 

acre-ft/year water right. Furthermore, even if Ash Grove were able to obtain a water right to 

such a large quantity of water, there is no guarantee that the company would be able to rely on 

that water right. In a dryer year than normal, 8 more senior water rights holder could require that 

Ash Grove cease its use thus resulting in the closure of the plant. The large amount of water 

required to operate a wet scrubber in the arid location ofthe Montana City plant poses one more 

reason why a wet scrubber is not technically feasible. 

For the reasons stated above, Ash Grove has concluded that wet scrubbing is not a technically 

feasible technology for the wet kiln at the Montana City plant. We also note that based on Ash 

Grove's latest information regarding the cost of wet scrubbing, the cost per ton of S02 controlled 

is nearly $11,000 per ton. We have included with this response the most recent costeffectiveness calculations prepared by Trinity Consultants. At this cost, wet scrubbing is 

unquestionably not cost-effective and so cannot be considered BART for S02. 

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Request No 2: Submit a 5factor analysis ofdry scrubbing techniques 

You had also requested that Ash Grove conduct a 5 factor analysis of dry scrubbing technologies 

for S02 control. Although you did not define what you meant by "dry scrubbing technologies," 

Ash Grove conservatively opted to include both Dry Adsorbant Addition ("DAA") as well as 

Semi-Wet Scrubbing. 

The BART rule states that a BART determination should address the following five 

statutory factors: 

1. Existing controls 

2. Cost of controls 

3. Energy and non-air quality environmental impacts 

4. Remaining useful life of the source 

5. Degree of visibility improvement as a result of controls 

Further, the BART rule indicates that the five basic steps in a BART analysis can be summarized 

as follows: 

I. Identify all available retrofit control technologies; 

2. Eliminate technically infeasible control technologies; 

3. Evaluate the control effectiveness of remaining control technologies; 

4. Evaluate impacts and document the results; 

5. Evaluate visibility impacts 

Ash Grove has prepared this analysis specific to DAA and semi-wet scrubbing, while otherwise 

remaining consistent with the methodology outlined above. 

I. Identify All Available Retrofit Control Technologies 

As at EPA's request, this analysis is limited to DAA and semi-wet scrubbing, this particular step 

ofthe analysis is pre-determined. 

2. Eliminate Technically Infeasible Control ~~chnologies

Ash Grove believes that neither DAA nor semi-wet scrubbing is technically feasible. DAA is in 

the earliest stages of development and while various companies have begun experiments in its 

application to cement kilns, it is not a proven technology at this time. 

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Semi-wet scrubbing is similarly unproven. Semi-wet scrubbing is not being operated on any 

cement kiln in the country. Ash Grove has proposed semi-wet control to EPA Headquarters in 

relation to its Midlothian, TX plant, but as an Innovative Control Technology project where Ash 

Grove would seek to implement a pilot project for the technology. That site was chosen because 

its S02 emissions are several fold higher than those from the Montana City plant. As discussed 

above, a control technology is technically feasible only if it has been previously installed and 

operated successfully at a similar type of source or if there is technical agreement that the 

technology can be applied to the source. In addition, the technology must be both "available" 

and "applicable." Technologies that are in development and testing stages are not considered 

available. A commercially available technology must also be "applicable," i.e., it must have 

been previously installed and operated at a similar type of source or a source with similar gas 

stream characteristics. Unless the technology is identified as both available and applicable, the 

technology is not considered technically feasible and, therefore, is not carried into Step 3 ofthe 

BART analysis process. Because semi-wet scrubbing is not being operated on any cement kiln 

in the country, let alone a wet cement kiln, it is not considered technically feasible. Again, as 

was clearly stated in the BART rule preamble, "[EPA does] not expect a source owner to 

conduct extended trials to learn how to apply a technology on a totally new and dissimilar source 

type. Consequently, you would not consider technologies in the pilot scale testing stages of 

development as "available" for purposes of BART review." 70 Fed. Reg. at 39165. As semiwet scrubbing is in the pilot scale testing stages of development, it must be eliminated from 

consideration in Step 2. 

Although both DAA and semi-wet scrubbing are properly eliminated in Step 2, we have 

nonetheless carried both technologies through into the subsequent steps. For DAA, this is 

because Ash Grove is proposing to install DAA as an innovative control technology on its 

Montana City kiln. For semi-wet scrubbing, Ash Grove has carried the technology through the 

subsequent stages so as to document all of the additional reasons why, even if it were technically 

feasible, semi-wet scrubbing would not constitute BART. 

3. Evaluate The Control Effectiveness Of Remaining Control Technologies 

Because ofthe technical infeasibility issues associated with both DAA and semi-wet scrubbing, 

it is extremely difficult to estimate the control effectiveness. For DAA, there is no record which 

can be used to estimate a specific system removal efficiency ("SRE"). Given the lack of 

information, Ash Grove is conservatively estimating that it will achieve an SRE of20 percent of 

the existing baseline. 1 Ash Grove has also conservatively estimated that semi-wet scrubbing 

I Ash Grove wishes to note that the existing baseline S02 emission rate has changed since the 

2007 BART submittal. As described in the 2007 document, an S02 CEM had been operating 

(continued ...) 

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will achieve an SRE of90 percent. While the SRE for semi-wet scrubbing may be extremely 

optimistic, Ash Grove does not believe that it changes the outcome of this analysis. 

4. Evaluate Impacts And Document The Results 

Step four for the BART analysis procedure is the impact analysis. The BART determination 

guidelines list the four factors to be considered in the impact analysis: 

• Cost of compliance 

• Energy impacts 

• Non-air quality environmental impacts; and 

• The remaining useful life of the source 

AGC has conducted an impact analysis for both of the two control options notwithstanding the 

fact that neither is considered technically feasible. 

Cost of Compliance 

Ash Grove's construction consultant derived the cost of a semi-wet scrubbing system based on a 

vendor quote that was not site-specific. Based on this cost, Trinity Consultants performed an 

economic analysis to determine the annualized cost for semi-wet scrubbing using the 

standardized OAQPS format. Ash Grove divided the annualized cost of semi-wet scrubbing by 

the annual tons of S02 reduced to determine the cost effectiveness for semi-wet scrubbing. The 

"annual tons reduced" were determined by subtracting the estimated controlled annual emissions 

(... continued) 

only a short time as of the preparation date of that submittal. As a result, very little was known 

about the variability of the S02 emission rate or how to control that emission rate through 

process changes. Since that time the plant management has employed the CEM to adjust kiln 

operation in a manner that the S02 emission rate has decreased considerably. Specifically, in the 

original BART submittal Ash Grove estimated that the annual S02 emission rate was 981 tons/yr 

derived by multiplying the average emission rate during 2006 (254 lb/hr) by the annual operating 

hours (7,740 hours). Based on the average emission rate during 2010, Ash Grove now estimates 

the hourly S02 emission rate as 612 tons/yr. Ash Grove believes that this revised emission rate, 

which assumes an average emission rate of 147 lb/hr and 95 percent availability (8,322 hours), 

more accurately characterizes the baseline emission rate for the plant as it has been operated 

during the past several years. 

70926750.10012028-00054 
U.S Environmental Protection Agency Region 8 

October 5, 2011 

Page 14 

from the baseline annual emission rate of612 tons/yr (see above). The estimated controlled 

annual emissions were calculated by applying the 90 percent control efficiency to the baseline 

annual emissions rate. The attached cost-effectiveness spreadsheet provides the cost 

effectiveness analysis related to semi-wet scrubbing. As can be seen from the analysis, the cost 

of control is not considered cost-effective. Other BART determinations have considered costs in 

excess of $4,000 per ton of pollutant controlled to be excessively expensive. Here, Ash Grove 

has documented that the cost would be $4,052/per ton. This is not considered cost-effective. 

As Ash Grove is proposing to employ DAA as BART, it did not prepare a cost-effectiveness 

analysis for the technology. 

Energy Impacts 

A semi-wet scrubber requires an additional fan of considerable horsepower to move the flue gas 

through the scrubber. Therefore, this element of the analysis also weighs against requiring a 

semi-wet scrubber as BART. 

Non-Air Quality Environmental Impacts 

The key non-air quality environmental impacts associated with semi-wet scrubbing, as opposed 

to DAA, is the consumption of water. DAA relies on the inherent moisture in the exhaust gas to 

operate. By contrast, semi-wet scrubbing requires 3.5 gallons/minute or nearly 2 million gallons 

of water per year. As noted above, the Montana City plant is located in an extremely arid 

location and its water right was just severely reduced by the State of Montana to match historic 

use. This means that new water use would require ash Grove to obtain additional water rights in 

an area where all surface water is fully appropriated and groundwater is limited and subject to 

being turned off during dry periods if a senior water right is affected. EPA has a long record of 

not requiring water intensive control technologies in arid regions due to the severe environmental 

impacts. In this case, semi-wet scrubbing should not be required as BART due to its 

consumption of significant quantities of water that may simply not be available. 

Remaining Useful Life of Source 

Ash Grove does not believe that the remaining useful life ofthe source is a relevant factor to the 

analysis. 

70926750.1 0012028·00054 
U.S Environmental Protection Agency Region 8 

October 5, 2011 

Page 15 

5. Evaluate Visibility Impacts 

The final step of the analysis is to evaluate the visibility impacts associated with the different 

control alternatives. In performing this assessment, it is important to note that S02 is not a 

controlling pollutant in Ash Grove's visibility ,malysis. The predominant driver of visibility 

impacts at Class I areas from the Montana City kiln are the NOx emissions. S02 emissions 

contribute an almost insignificant amount to visibility impacts from the Montana City plant. As 

Table 5 below shows, this means that the imposition of any S02 control at the plant results in 

minimal visibility improvement. The incremental improvement in visibility attributable to 

requiring semi-wet scrubbing as BART is a mere 5 percent improvement or a 0.16 dv 

improvement in visibility. Based on the annualized cost of the semi-wet scrubbers, this results in 

a cost of well over $13 million dollars per deciview of improvement. This cost is clearly not 

justified and semi-wet scrubbing should not be required as BART. 

TABLES 

Maximum 

8th High 

(t.dv) 

Change 

From 

Baseline 

(dv) 

Percent 

Improvement 

Existing 2.699 -­ -­

DAA 2.666 -0.033 1% 

Semi-Wet Scrubber 2.539 -0.16 6% 

A more detailed summary table of the modeling results is included as an attachment to this letter. 

6. Select BART for S02 

Based on the analysis above, there is a strong argument that semi-wet scrubbing is not a 

technically feasible control technology. However, even if that concern is ignored, the 

environmental impacts, cost impacts and lack of any material improvement in visibility 

associated with semi-wet scrubbing all combine to demonstrate that it would be arbitrary and 

capricious to consider this technology to constitute BART. Although similar arguments against 

DAA being a technically feasible control technology exist, Ash Grove is willing to take on this 

technology as a innovative control and commit to operate the technology such that S02 

emissions are limited to I47lb/hr (30 day rolling average). As with semi-wet scrubbing, this 

control technology will not result in significant visibility improvement. However, the 

development ofDAA technology for wet kilns may prove useful at other plants across the 

country and so there is separate merit in installing the technology. 

70926750. J 0012028-00054 
U.S Environmental Protection Agency Region 8 

October 5,2011 

Page 16 

IV.	 PM BART 

Although EPA did not request additional information regarding BART for PM, Ash Grove 

wanted to update the agency as to its current plans for PM control. As noted above, Ash Grove 

currently operates an ESP for controlling PM from the kiln. Estimated annual PM emissions 

have averaged approximately 100 tons/yr with the ESP in operation. However, Ash Grove is 

moving forward with installing a baghouse on the kiln exhaust which it anticipates will decrease 

kiln PM emissions from approximately 37 lb/hr used in the modeling to approximately 5 lb/hr, 

an estimated reduction in actual PM emissions ofover 85 percent. While NOx, not PM, is not 

the primary driver of visibility impacts, we wished to make EPA aware of this increase in 

emissions control that the company is investing in. 

V.	 Statement of Certification 

Included as an attachment to this letter is a Statement of Certification from Dick Johnson, the 

plant manager of Ash Grove's Montana plant, certifying the accuracy ofthe statements and 

materials comprising this submittal. However, Ash Grove is unable to certify that the submittal 

is complete given the unreasonably short time frame allowed for the response. 

Please let me know if you have any questions after reviewing this submittal. 

cc:	 Dick Johnson 

Jeff Briggs 

Fran Streitman 

Curtis Lesslie 

Bob Vantuyl 

Kasi Dubbs 

Attachments: 

1. Wet scrubber cost-effectiveness analysis 

2. Semi-wet scrubber cost-effectiveness analysis 

3. Revised modeling summary 

4. Certification statement 

70926750.1 0012028-00054 
AGC Montana City
 

SO, Control Cost Effectiveness Analysis
 

Wet Scrubber
 

Direct Costs NoCc:Ii 

Purchased E ui ment Costs 

MECS 11)1IIIW8\"(: SCl'\lbbo;lrQuolc; 2010 

$9.000 k S..rut>~r. S 1.~(lO k Rea~ell1 rrr-:r &. tiller 

$24U k hIll",. t>uddlll{l_ S!lOO ShJJ!lc J"p'_I', $600 k 

Wei SCI\lllller Ul\Il SlZ.I4II.0(JO HnUelll hllOdhnll.l 

111~lrum,,"llllion mel 

Sales Tax (3°,. aCEe) S,'(,.L~O(l () 03 A 

Freillhl So'oorEe $(,07.(J{)(1 OOs A 

SuhtotaJ. I'ufchllsed LqulpmCmCOs\ (PEe) SI3.JJI.lU(l fl 

l'D"'.=,,.'-"'"'Slll"'"!!lllli"'"''-'C-'''os'"'\S'--­ -----1 006 H. from CONTROL COST MANUAl 

Fou"daliOll ((,° 0or PEe) S7KIl.f>72 EPA 45~ 'H·OZ-()()] (eeM] 

Suppons (60 0 of PIT) PKh_f>7~ O()(,13 fmm CCM 

HlIfldlitl!lllOd ErcCllOIl (40°'. or ['Ee) S:'.~44A80 () ~o H. frolll CCM 

Elco.;mcal(IO'oofPECj $131.112 001 B,rromCCM 

Pipll1p.(30.oofI'FC} SJ.'I,n..'f,1l (1.30 B. rlOm CeM 

~lsulB.1I011 for Dllc",,'orl (1% of PEl') S13 1.112 0.t}1 fl. from CCM 

P

.c,,,,"","',"'.l!''''o.•'''O!.!r1'EEC''-------,SC-"hCC'O__,''~L''''''-'w--,.,~'''--,sta~Il'--,''-••-;CeCC",--',-~S'C''''I~:~~~'C;.,,~~'--, ---j(l.lll H. [.om CCM 

Tolll DirKI lOllI SZ4.ZSS.720 

-'.In'''d''';r''''~,,t-'C'''os,,ts'-- ;-:bl:::.--,''~c:,:::il1P.:-------------------,S,.;,;:;,,,:;;,m"''',----\MECSlJovt18 B.\'eScl\Jl>hcl()uole20111

CooslruclJOll and Field Expense (10°'0 ofl'EC) S1.3 tl.120 0 to fl, CCM 

Contractor h::es (IOO'oofI'ECj S1..'I11.120 !l III fl. CCM 

Sl.lI.n-up (1 0"0 ofPEC) S131,112 (I,or Jl.CCM 

I'erfomulncc res' (IO--oofI'EC) SI,ll.J 12 001 B. CCM 

",C","'''''''''-''~""""'''-' "'20"'%'-"O"'f1CE'E"'CL------COT..,"'-,.'~'"-,di..,'K-'.."C..,"'-, __~~;",:~,;,~~",:;,:,,~,-,---jAGe. EnllllloemHI. bUmble 

Tolal lotpitallnvefihnenl (Tn) 

Direct Annual Costs 

Hour> per Year 950'0 Annual Run Time 11.322 

Oneratlll Labor 

0l'elalOr (0 5 hris/lin. 3 shlns:dav. 365 d.-yr. S25,hr) 

SU'lCl'\'lsor 15°'0 oj o>crator 

SubtOlal 0l>cralllltll.<l(lor 

Sl\.MIll 

520B 

SIS.Nt 

CCM 

Labor (D,' hrlshlti. 3 ~hlft~'dlIy, 365 d:vr, :ii25'hr) 

Maleflill 1000/. of m<linlenlln~ll1t>or 

SuhlOtal. Mawtmane<.: 

S13,688 

S13 Mil 

S27.:n5 

CCM 

lJtlhtles 

f]octrlcl1 

PUl1ll' (kWj -l6J 51 

MECS [)vnawa~e Scrtlbl:>er Quote 2007. 510 hp (l1l0 

kW) wsl..'t1l U.'illge. scaled up accordlnp. to () 6 power 

n>le fron> 75,000 -;cfln {I 15,057 aclln)'o 160,OOD adn> 

,if;. 350 dCll Fnue O(a... l1o,," rate 

Cil-il (S:kW-hrl ~uh\(lllli. l:k,,;ln<,;ll, -----;s~~~';"~~"'~~+; ---1 NorthWestern Enerll:\' smaJllndu.i1l\', Helena, M'I • 

Lllm~SI~le Slufl".' 

Am'Xlol R,;qu"c:J (llI11~',) 3.2% 

MECS I~Tlllwavc ScruhberQuole 2007. 650 Ih hr 

hmcsl'Ilc USllllc scaled up acu,rdintllO 0.6 J'l',,"er mlc 

from 75,000 ,;erm (115.057 act'm) 10 160.000 ac:Jln IfI' 

350dCllFl1ucllasl!owrate 

Ch,,(S'lu'l) Sublolal, 11m..: ---;C~C7~~-l7'·:"76 ---1 (S15 from Table 3 1-2 of NLA· evaluation) 

MECS [)ynllwllve Scrtlhher Quote 2007, J I lllIl'lmn 

wakr uSiltle ';Caled up accordintllO 0 6 [lOWer rule ironl 

75,000 'iC11ll (115.057 aclm) 10 IMl.OOO OcCllI ti ]50 

Amounl kcqu"':d (tlf'>l'l) 1711 dell F lluejl.as no,," rale 

CllSl (SdOOO ~lIllns) ~ublOIIiI. wa,cf---;cS:",~:4"'5;C'~ Helena Water - S2 60 !>cr 7411ll,allons' 

~Iud e DI~l'>O!'al

MECS Dyllawavc Scruhl:>er QuOle 2007.1.350 lbll>' 

sludlle p.encralJOIl, scaled up accordmp. hl 0 (, JXl"'cr 

rule irom 7S,O()O >;cfrn (11S,057 act'm) 10 160,000 act'm 

Amounl Geueraled (tpy) 6,84(, fa' 350 dell F tluejl.asllowrale 

D1sprnal Fe.: (Siton) SubtolO(I. Sludge -----;S"'.1:"';~"'~~K",;---1 1

,eWll Wld Clark CounlV Landfill d 

Sublotal. Uhhlles $716,162 

TOlal DirKt '\nnu.1 Costa 5759,278 

Indirect Annual Costs 

Overhead (60G ,0 of sum of operaullg. ,u[ll:l".·I.or, maintenance lal>or & llla'enals) S300,271 [)oesnullndlJdee!eclrlcll'\ 

AdrnlUistraliv.: (2% TCI) S600,448 O,02TCI 

Property Tax (1°'0 TCl) S300.224 () 01 TCI 

lusurwlcc(lo'oTClj S300.224 001 TCI 

Ca }]jal Rec:o~el"\' 15 vear life 7 S3 296 3U1 

Totallndir('(;t Annual CO$t s.a,797,468 

Conclusion 

rolll Annu..liu·d CUJit 55.556,746 

l'ollutant t:mission Rale Prior to Scrubht'r (lOnl' SO/yr) 612 

111I.,ed un 20](1 aH:rlltle ':1ll15Sllrl nu~ of 14711->'-1->1 S02 

(with I'roccs.~ ...",,,ols Irnplemeillcd). ';5"" ul'lnne 

Pollutant Remo\'i·d (tons SOl/lr) 

C".I Pt'rT"n "rl'oIlUlanl !Wn",,,flI 

lIIa••i"'i 900'0 removal. A.>slJlIles 9~"··" conlrol C<julprn"'l1 upume 

TOlal ,\nllullli"l"II COlli 

IlO'£i~·;.. ... lmp....vt'n'.1I1 

5 I lkch'iew 1m rOH'mt"nl 

SS,556.746 

1,u60 

$34729,663 

hl1p' ''''''''''' Ilonhwestern':n.:rgy com oor<';uslomers'shllrl'd'nlt.xompure.aspx 

h NLA E~ll.lua1J(I] - WET FLUF GAS DESULFURilATlON TECHNOLOGY EVALUATION. JANUAkY 2(KI.\ (So.r8,-,"11 and Lundy I.LC) 

hltp.!Iwww Cl hckna.m I.U !ildep"nlllo:tll.'!"lIdnlllll~lralL ~'C->oCr\'IC"""" filllU1CC,ul1 ht)'-eUSlomcr-ser~Il:Cs.'-eU slonler,mquLrI e;,.- water-rales. hlml 

d http 'Iw...."" co lew,s-clllrk.ml.usldcl'0rtmalls.'pubhc_worhi.•olid_wastc.html 
AGC Montana City
 

S02 Control Cost Effectiveness Analysis
 

Semi-Wet Scrubber
 

Direct Costs Notes

Purchased EflU!nment Costs 

Sohos Enhanced Semi-v.et Serubber QUOIC 2010 (2010 

Scrubber Unit $),690,000 Quote)

Instrumentation S7JO.OOO 2010 Quote 

Sales Tax (3% of EC) SI32,600 00) A

FrelPht $300000 2010 Quote 

Subtotal, Purchased Equipment Cosl (PEC) S4JI~2,600 B 

Direct Installation Cosls 

Ci\'11 Structural (inel. mal'l) 

Foundation 

Supports 

Handling and Erection 

ElecLrieal 

Piping 

Insulation for Ductwork 

Paintin 

Subtotal, Dmxt Installation COSI 

$1,020,000 

Inel 

Inel 

$1,690,000 

$620,000 

Incl 

Incl 

Incl 

$),330,000 

2010 Quote 

2010 Quote 

20lO Quote 

Total Dirert Cosl $8,182,600 

Indirect Costs 

Ellglnccnng 

Construction and Field Expense 

Contractor Fees (10% ofPEC) 

SIar1-llP (I % of PEC) 

Perfomlance Test (1% ofPEC) 

Conlinllcnclcs 

Total Indirect Cost 

$400,000 

S660,OOO 

S48\260 

S4R,526 

S48,526 

$1.820.000 

S3,~62,Jll

2010 Quote 

2010 Quole 

f,pm CONTROL COST MANUAL· EPN4l2/B·Ol· 

001 (CCM), Seclion 5.1, Chapter I, Table I 3 

(,CM. ~tlon :'i. I. Chapter I, Table 1.3 

CCM. Sccllon 5 I. Chaptcr I, Table I 3 

2010 QuOIC 

Tnhll Ca'lihlllnvcsimeni (TCI) SII,644,912 

Direct Annual Costs 

Hours per '{ car 95% Annual Run Time &,)22 

~t'" Labor 

Operator (0.5 hr/shin, 3 shins/day, 365 d

Suocrvisor (15% of oneralor) 

lyr, S25/hr) 

Subtotal, Operating Labor 

$13,6&& 

$205) 

$15,741 

estImate 

CeM 

Maintenance 

Labor (0.5 hr/shIO. shIfts/day. 365 dlyT. 

Matenal (I OD% of maintenance labor 

$25/hr) 

Subtotal, Maintcnance 

$1 ),6&8 

$136~UI

S27,J75 

estlmale 

CeM 

Utilities 

Electncllv 

Demand (kW) 75 16 

Estimated based on 2011 Turbosome syslem for a lime 

kJin wllh 69.000 cfm nue gas al 300 deg F - 377,600 

kw-hr. scallXi up aCCQrding to 0.6 powcr rulc to 160,000 

cfm 

Cost (SIkW-hr) 

Subtotal, Ek:ctrlclt) 

$00671 

$~I,96&

NorthWestern Energy: small mdustry, Helena. MT a 

Hvdrated LIme 

Amounl ReqUIred (tonly.-) 

Cost (S/ton) 

Subtolal, Lime 

1,096 

$14500 

$15&,910 

Based on 2010 average cmission rate of 147 lblhr S02 

(wllh process CQntrols implemcnted), CaOH/S02 ratiO 

of 1.5. 96.8% puril) 

$/ton deli\'ered (Quote from Graymonl) 

Subtotal, U\llibes $200,&7& 

Water 

Amount RCqUlfcd (gpm) 

Cost (S/1000 gallons) 

Subtotal. Waler 

3 S 

13476 

S6.075 

AGe - Engmccnng Estlmatc 

Helena Water - S2.60 per 74M gallons 

Total Dircct Annual CO.'its S250,068 

Indirect Annual Costs 

O\·erhead (60% of sum of opcrotmg. supervisor, mamtenanec labor & matenals) $124,&60 

Admlnls(rauve (2'111 TCI) S232.K9R 002 Tel. CCM, Sec 5 I. Ch I. T,ble I 4 

Prope~ Tax (1% TCI) Sllfl,449 0,01 TeL CCM, Sec:'i I,Ch I. Table 1.4 

Insurance (1% TCI) SI16,44\;> OOITCI,CCM,Sec51,Ch I,T.ble 14 

CaVltal Recoverv (]5 ear hfe. 7 oereenl mterest) $1.27R.549 CCM, Sec I, Ch 2, EQn 2.8a 

Total lodirect Aonual Cost SI,I<69,205 

Total Anouali7.ed Co~t S2,119.273 

Based on 2010 average emiSSIOn ratc of 1471blhr S02 

Pollutant Emissioo Rate Pdor 10 SHubbcr (tons SO}/yr) 612 (with process CQntrols implemented), 95% uptime 

Pollutant Removed (tons SOl/yr) 523 90% removal. Assumes 95% CQnlrol equipment uptime 

Cost P"r Ton of PolI.fanl Remo\'ed 

TOial AnDualized Cost S2.119.273 

Deci~iel't Improvement 0.160 

S I Dech'icw 1m lrOl'emeol 513,245,457 , htt p :/1 WWWCI helena.rnt,us/ de pa rtrne n / IS admJnlstrallHl servlCCS finance/utility customer sen Ices/customer mqUlnes/waler ralCS hlml 
Method 8 Mode 5 post processing. 

Pe

Chan

Change from Ba

3yr 98th Baseline Based Ba

Natural Maximum 8th_ Percentile on Maximum Ma

Background Ranked Ranked Ranked High Ddv (22nd High) 8th-High Ddv 8th-H

Method Ddv 

Class I Area: 

Gates of the 

Mountain 

BaselinelProcess	 

2001 Ddv 2002 Ddv 2003 Ddv Ddv 

4.196 4.638 4.234 

3.777 4.527 4.194 

3.698 4.037 4.072 

3.217 3.291 3.458 Annual Average	 2.699 2.699 N/A N

Control	 3.118 3.169 3.300 

2.869 2.872 2.897 

2.769 2.724 2.768 

2.461 2.597 2.699 

Total # days over 0.50 ddv	 98 82 71 total across 3yrs 251 

Total # days over 1.0 ddv 56 43 42 total across 3yrs 141 

4.170 4.581 4.174 

3.748 4.486 4.150 

3.629 3.984 3.987 

3.174 3.231 3.412 20% Reduction. OAA Annual Average	 2.666 2.666 -0.033 

3.094 3.112 3.240 

2.850 2.825 2.878 

2.706 2.69 2.681 

2.420 2.571 2.666 

Total # days over 0.50 ddv	 98 82 69 total across 3yrs 249 

Total # days over 1.0 ddv 55 42 41 total across 3yrs 138 

4.078 4.376 3.994 

3.646 4.343 3.962 

3.388 3.794 3.682
 

90% Reduction. Semi- 3.020 3.015 3.250
 Annual Average	 2.539 2.487 -0.16 

Wet or Wet Scrubber	 3.013 2.912 3.038 

2.781 2.657 2.813 

2.486 2.575 2.551 

2.277 2.487 2.539 

Total # days over 0.50 ddv	 97 81 66 total across 3yrs 244 

Total # days over 1.0 ddv 52 37 39 total across 3yrs 128 

CONCLUSION: Since Nitrates is a largest percentage of the deciview a large reduction in sulfates does not yield a large reduction in deciviews. 

See individual year tabs for species % of deciview for top 22 ddv. 
Statement of Certification 

I certify under penalty oflaw that I have personally examined and am familiar with the 

infonnation submitted in this document and all attachments and that, based on my inquiry of 

those individuals immediately responsible for obtaining infonnation, I believe that the 

infonnation is true, accurate, and complete. I am aware that there are significant penalties 

for submitting false infonnation , including the possibility of fine or imprisonment. 

Signature: 

Title:~\ et", t ctk. ~l~-l v 

Date: 1D-)- lD JJ