1 ENCLOSURE 3 **PUBLIC PA RTICIPA** 

**TION RECORD** As required by 40 CFR 51.102(e), the complete record of testimony is located at the Department of Environmental Quality. The d epartment contact to access this information is the Director, Air D ivision

. As requ ired by Section 2.1(h) of Appendix V of 40 CFR Part 51, below is a summary of the testimony received and responses thereto. Included is a brief statement of the subject, the identification of the commenter, the summary of the comment and the response (ana lysis and action taken). Each issue is discussed in light of all of the comments received that affect that issue. All comments have been reviewed and responses developed based on an evaluation of the issues raised in consideration of the overall goals an d objectives of the air quality program and the intended purpose of the document under review. 1. **S UBJECT**  **:** Sulfur dioxide (SO 2 ) emissions. **COMMENTER :**  National Park Service **TEXT :**  DEQ has proposed addition of a caustic wet scrubber to control SO 2 emiss ions from the rotary k iln. W e agree and fully support this proposal. **RESPONSE :**  Support for the proposal is appreciated. 2. **SUBJECT :**  Nitrogen oxide ( NO X ) emissions, cost effectiveness of selective catalytic reduction ( SCR ) control

. **COMMENTER :**  National Park Service **TEXT :**  We agree that SCR in a high - dust location on this rotary lime kiln poses problems that render this approach technically infeasible in this situation. There is a growing successful track record of SCR use in the U nited S tates that indi cates that spent catalyst and ammonia use are not a significant risk if proper procedures are followed. The following comments are directed to O - N Minerals' June 4, 2009 response to DEQ as it relates to the cost - effectiveness of a tail - end SCR system loca ted down stream of the existing baghouse. Except as noted elsewhere , we accept O - N's estimated costs at face value, and appreciate their effort to provide that information in such detail. W e believe that O - N's operating cost for "Supplemental Natural Gas Firing" may be overstated. W e recently received an analysis of tail - end SCR as it might be applied following a wet scrubber at Basin Electric Power Cooperative's (BEPC) Leland Olds Station Unit #2 in North2

Dakota. In that analysis, BEPC assumed that enough heat could be recovered that the additional natural gas heating requirement to operate SCR would be only 50 ° F. If we compare that Leland Olds estimate to the 200 ° F increase estimated by O - N, there is the potential to cut natural gas use by 75%. We believe that O - N has underestimated the effectiveness of SCR at 80% control efficiency (305 tpy reduction). It is generally assumed that SCR can attain at least 90% control --which should be especially likely in a low- dust location. (The Leland Olds Unit #2 BART analysis assumed 90% control.) A 90% reduction at O - N could result in up to 340 tpy removal. We entered data into a spreadsheet that adjusts the O - N Minerals results to account for reduced reheat cost and increased NO X removal. The resulting $5,100 per to n cost - effectiveness is substantially lower than the $7,500 per ton estimated by O - N Minerals. Unless a control technology option is determined to be technically infeasible, the full five - step BART process should be applied. In this case, tail - end SCR is technically feasible and its costs are low enough to justify an analysis of the visibility improvements that would result from its application. **RESPONSE :**  The comments offered by the National Park Service (NPS) do not address - - or change - - our position as s tated in our September 22, 2009 letter responding to NPS’ s original comments (provided during NPS’ formal 60 - day review period). As detailed in the letter, SCR has not been applied to or demonstrated on any kiln (cement or lime) in the United States . The limited data derived from one European cement kiln SCR application indicates poor performance (resulting in the SCR being replaced by SNCR at that location). W e have found no use of SCR on a lime kiln anywhere. Accordingly, and as detailed in our 9/22/09 letter, we find that SCR is not a candidate for technology transfer for BART consideration

. Nonetheless, we offer the following responses to the points raised by NPS during the public comment period. It is uncertain that it would be technically feasible to retrofit th e existing rotary kiln setup at the Strasburg site to accommodate a heat exchanger for the purpose of heating the baghouse exhaust. K iln heat is already recovered and used to heat limestone in the preheater, so it is unlikely that there wou ld be enough residual heat to appreciably raise the baghouse outlet stream temperature

. It is not reasonable to conclude that O - N’s natural gas heating requirement would be 50 ° F (i.e., would be reduced by 75%) based on the requirements of a coal -fired boi ler ins tallation using heat recovery. As stated in our 9/22 /09 letter, we believe 80% is an appropriate control efficiency basis for a novel application of SCR such as that on a lime kiln. There are data available from one application of SCR to a kiln (a cement kiln, not a lime kiln) in Europe; the data show that the SCR achieved an average control efficiency below 50%. W e also note that several recent entries for applications of SCR on EPA’s RACT/BACT/LAER3

Clearinghouse (RBLC) are listed at efficienci es below 90% , which reflects the process specific nature of SCR effectiveness . As we previously concluded, although SCR is capable of achieving 90% reduction efficiency in certain applications, it would not be appropriate to apply that standard to a n appl ication of SCR to a lime kiln. The adjusted cost per ton value ($5,100) presented by NPS is based on several assumptions. First, i t pre sumes that a heat exchanger retrofit is technically feasible on the rotary kiln. Secondly, NPS’ s revised calculation d oes not include an adjustment to capital costs to reflect the cost of the retrofit, if it is feasible. Finally, the revision is based on 90% control efficiency, which, as explained above, we find to be inappropriate in this case. W e therefore do not find th e adjusted cost per ton to be an accurate indicator of SCR control cost in O - N’s case. Modeling to assess the visibility improvement likely to result from application of SCR at O - N has not been conducted, because SCR was determined to be cost prohibiti ve. Additionally, as detailed above, SCR has not been applied to a lime kiln and we do not find it to be a candidate for technology transfer consideration under the BART guidelines. The analysis conducted to determine BART for O - N is fully consistent wit h the five -factor evaluative approach outlined in the BART guidelines (40 CFR Part 51, Appendix Y). 3

. **SUBJECT :**  Changes to permit conditions and SIP revisions. **COMMENTER :**  O - N Minerals (Chemstone) Company **TEXT :**  The proposed BART permit contains numero us and specific conditions that we understand will become part of Virginia's state implementation plan (SIP) once finalized and approved by the U.S. Environmental Protection Agency (EPA). Given that this facility in the near and long term may undergo perm it changes that could result in future permit cond i tions that differ from those that incorporated in this permit, we have previously suggested to DEQ that this permit contain certain language to allow for permit modifications to minimize the possibility of having to modify the SIP to accommodate future permit requirements that may conflict with the BART permit as drafted. W e appreciate that DEQ has considered this request previously and we understand some regulatory options may exist to reduce the opportun ity for SIP revisions to be necessary. However, we remain concerned that future permitting efforts at the facility may require SIP revisions before they can be implemented without such permit revision provisions being incorporated in this permit. Accordi ngly, we appreciate DEQ reconsidering this aspect of the permit during this phase of the process. **RESPONSE :**  We understand O - N’s desire to simplify the administrative SIP revision process that may be required to address future modifications at the facility. Nonetheless, there is no way to avoid the need for a SIP revision if O - N wishes to change the terms of the BART permit in the future. W e note that this is the case for any facility holding a n air permit that is part of Virginia’s SIP.4

4

. **SUBJECT :**  Scrubber installation date. **COMMENTER :**  O - N Minerals (Chemstone) Company **TEXT :**  We previously suggested that Condition 4 be revised to accommodate the timeframes that the company is working under relative to installation of an SO 2 continuous emission mon itoring system (CEMS) and, if necessary, the design, engineering, permitting and installation of add - on control equipment as applicable. DEQ has not agreed to accept our proposed revision to this condition in prior discussions. W e would prefer not to for mally challenge the permit or delay the revision to the SIP. However, we cannot agree to the proposed language of Condition 4 which would require us to install a scrubber by September 10, 2010. W e must have time to demonstrate that a scrubber is not nece ssary and obtain approval for the alternative control technology. If we cannot make that demonstration after a reasonable period (including the requirement to install a CEM for SO 2 ), we will need adequate time to install the scrubber (assuming we continue to operate the kiln). W e recommend that Condition 4 clearly state that we have until September 10, 2011 to seek approval of alternative control technology. Therefore, we propose the following revised Condition 4: 4. Emission Controls: Rotary Kiln - No later than September 10, 2010, sulfur dioxide (SO2) emissions from the rotary kiln (U5) shall be controlled to achieve the SO2 limits set forth in this permit. Unless the Director , Valley Regional Office, approves inherent process scrubbing as an alterna tive control technology by September 10, 2011, a wet scrubber shall be installed by September 10, 2012. The wet scrubber or other technology employed to meet the SO 2 emission limits shall be provided with adequate access for inspection and shall be in ope ration when the rotary kiln is operating. (9VAC5 - 80 - 850, 9VAC5 -40 - 7580, 9VAC 5 -40 - 7590, and 9VAC5 -40 - 7650) We also think it is important to state our understanding that the Director will agree that inherent process scrubbing is an approvable control techno logy if our SO2 emissions are consistently within the permit limits. W e agreed to install a CEMS to provide data to demonstrate that inherent process scrubbing is effective and capable of meeting the BART permit without additional controls. Additionally, we understand that given the newness of continuous emission monitoring for SO 2 , occasional deviations of the SO 2 limit should not preclude the Director from granting approval. **RESPONSE :**  We agree that an extension of the deadline to install a scrubber is appropriate, provided that the emission limits determined to represent BART for SO 2 from the rotary kiln (Condition 23) are met by September 10, 2010. Accordingly, we have changed Condition 4 to read:5

**Emission Controls: Rotary Kiln** 

– No later than Septe mber 10, 2010, sulfur dioxide (SO 2 ) emissions from the rotary kiln (U5) shall be controlled to achieve the SO 2 limits in Condition 23. Unless the Director, Valley Regional Office, approves inherent process scrubbing as an alternative control technology by September 10, 2011, a wet scrubber shall be installed by August 1, 2012. The wet scrubber or other technology employed to meet the SO 2 limits shall be provided with adequate access for inspection and shall be in operation when the rotary kiln is operatin g. (9 VAC 5 - 80 - 850, 9 VAC 5 -40 - 7580, 9 VAC 5 -40 - 7590 and 9 VAC 5 -40 - 7650) Note that the scrubber installation date has been changed to August 1, 2012 (instead of September 10, 2012 as proposed by O - N) to comply with Virginia’s BART regulation (9 VAC 5 -40 - 7590.4). 5

. **SUBJECT :**  We t scrubber. **COMMENTER :**  O - N Minerals (Chemstone) Company **TEXT :**  We also believe a wet scrubber will be sufficient and ask to remove the reference to "caustic" in the appropriate conditions including, but not limited to, Conditio ns 4, 9, 14, and 26j. **RESPONSE :**  As requested, we have removed the word “caustic” from all references to the scrubber throughout the permit.

TEMPLATES \ SOURCE - SPECIFIC\ PLN03 SRCESPEC\ O - N MINERALS \ ONM - SIP - 3.DOC