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From: Putney, David 

Sent: Thursday, December 18, 2014 10:51 AM 

To: 'Van Der Meyden, Henk' 

Cc: Matthew Hakos (mhakos@rti.org); David Green 

Subject: RE: Primary Aluminum MACT question 

Mr. van der Meyden, 

Thank you very much for your interest in the supplemental proposal for 

RTR amendments to the primary aluminum NESHAP that was published in 

the FR on 12/08/14 and for bringing these issues to my attention. I 

will attempt to address your concerns briefly in this email, but I 

want to mention that it would be very helpful if you would include 

your questions (i.e., from your email below), along with any other 

comments you might have on the supplemental proposal, in a comment to 

the docket (Docket ID No. EPA-HQ-OAR-2011-0797) during the public 

comment period. That way these issues (and the EPA responses) will be 

in the response to comments document. 

In your first question you asked what limitation the bag leak 

detection systems (BLDS) are to be used to demonstrate compliance 

with. As proposed, the RTR amendments would require the use of either 

a BLDS or a particulate matter (PM) continuous emissions monitoring 

system (CEMS) to demonstrate continuous compliance with the newly 

proposed PM standards. 

In your second question you ask for clarification of paragraph 

§63.848(o). Specifically, there is confusion as to whether a BLDS is 

required in order to demonstrate continuous compliance with the newly 

proposed PM standards or if a BLDS is simply one of the options for 

demonstrating continuous compliance. The cited paragraph reads, in 

part, “[f]or each baghouse used to control PM emissions, you must 

install, operate and maintain a bag leak detection system according to 

paragraphs (o)(1) through (3) of this section, unless a system meeting 

the requirements of paragraph (p) of this section, for a CEMS and 

continuous emissions rate monitoring system, is installed for 

monitoring the concentration of particulate matter.” (emphasis added). 

So, we intended to give 2 options for demonstrating continuous 

compliance with the newly proposed PM standards – either a BLDS or a 

PM CEMS. 

In your third question you ask for the basis for requiring BLDS (or, 

presumably, PM CEMS). I’m not completely clear what you are asking for 

but I think you are asking for the regulatory basis for this 

requirement. That is, the regulatory authority underlying this 

requirement. At the beginning of the regulatory text in the FR notice 

we cite 42 U.S.C. 7401, et seq. as the authority for these 

requirements. If I misunderstand your question, or if you want a more 

specific regulatory citation, please let me know. 

 
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Thanks again for bringing these issues to my attention. 

David Putney, Environmental Engineer 

U.S. Environmental Protection Agency 

Office of Air Quality Planning and Standards 

Sector Policies and Programs Division 

109 T.W. Alexander Drive, RTP, NC 27711 

Mail Drop D243-02 

Ph: (919) 541-2016 Fax: (919) 541-3207 

Email: putney.david@epa.gov 

From: Van Der Meyden, Henk [mailto:Henk.VanDerMeyden@alcoa.com] 

Sent: Wednesday, November 26, 2014 9:18 AM 

To: Putney, David 

Subject: Primary Aluminum MACT question 

Mr. Putney, 

I am following up on my call from 11/25/2014 regarding the 

supplemental proposed rulemaking for the NESHAP for Primary Aluminum 

Reduction Plants which was signed on 11/13/2014. I have a couple of 

questions regarding the use of bag leak detection systems as proposed 

under 63.848(f)(6) and (o). 

The proposed rule amends Section 63.848 by adding a new paragraph 

(f)(6) which states: 

“(6) For emission sources with fabric filters that choose to 

demonstrate continuous compliance through bag leak detection systems 

you must install a bag leak detection system according to the 

requirements in paragraph (o) of this section, and you must set your 

operating limit such that the sum of the durations of bag leak 

detection system alarms does not exceed 5 percent of the process 

operating time during a 6-month period.” 

First, can you clarify what the limitation is that the bag leak 

detection systems are to be used for to demonstrate continuous 

compliance with? Is this to be an option in lieu of doing a daily 

visible emissions check as is currently required under 648(g), or is 

this a new separate requirement? Second, the wording of the paragraph 

indicates that a bag leak detection system is one option (“choose”). 

Yet, paragraph 648 (o) indicates that a bag leak detection system is 

required (“For each baghouse used to control PM emissions, you must 
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install, operate and maintain a bag leak detection system...”). Can you 

clarify the option/requirement for bag leak detection systems? Third, 

there is no mention in the preamble of the proposed rule regarding the 

basis for requiring bag leak detection systems. Can you clarify the 

basis for the proposed requirements regarding bag leak detection 

system? Is there a document in the docket? 

Thanks for your consideration, 

Henk van der Meyden, PG 

Sr. Environmental Consultant 

Alcoa Inc. 

Cell: (843) 296-3359 

henk.vandermeyden@alcoa.com