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What should you be asking your DAHS vendor with respect to the PC MACT?

Posted: March 26th, 2015

Author: All4 Staff 

Right about now you should be working with the vendor of your Data Acquisition and Handling System (DAHS) on providing a compliance solution for the Portland Cement MACT (PC MACT).  What type of questions should you be asking?  How can you ensure that you will get what you need?  Read below as ALL4 continues its series of blog posts concerning the PC MACT.  Hey, we all can’t wait for summer, but we may be anxious about the fall with the September 09, 2015 compliance deadline looming.

The single most important question that you should be asking your DAHS vendor is “What exactly do you need from me?”.  Not to under-value the effort associated with programming your DAHS for compliance with the PC MACT, but, if your DAHS vendor is expecting a “0” or “1” from you, the burden is now yours.  Your DAHS vendor may be expecting a digital status bit for periods when PC MACT regulated sources such as kilns, clinker coolers, raw mills, and slag dryers, are in specific operational states (i.e., “in startup”, “in normal operation”, “in shutdown”, or “not operating”).  Providing the DAHS vendor discrete operational status makes their job a lot easier and requires the plant to develop their own digital status bits.  Don’t get me wrong, I would rather see the plant in control of these definitions.  However, providing operational status requires the plant to interpret the regulatory requirements, develop (and document) the algorithms, and implement signal programming.  Ultimately, operational status impacts calculations that determine compliance averages, so the programming should be tested to verify its accuracy.  Make sure that you find out what your DAHS vendor needs now, so that you can minimize surprises and properly manage your limited resources. 

A DAHS continuously collects data in an automated manner.  Plants may need to simultaneously collect data outside of the DAHS necessary to demonstrate compliance with the PC MACT.  Another item that should be discussed with your DAHS vendor is the capability to input data collected outside of the DAHS.  How will your DAHS allow you to enter data made available today, for a time-frame that occurred in the past?  Two main examples are the use of mercury (Hg) sorbent tubes and clinker production.  Hg sorbent tubes will be collected for a period of time and sent to a laboratory for analysis, and the results will be available several weeks later.  The resulting Hg concentration must be entered into the DAHS for the time-fame during which the Hg sorbent tubes were collected and compliance will have to be recalculated based on the updated data.  In addition, the PC MACT allows for the reconciliation of clinker production based on inventory measurements.  Will your DAHS allow you to input a retroactive clinker production rate based on inventory measurements if you chose this compliance option?  This raises another consideration for plants opting to reconcile clinker production, are you providing a clinker production rate to the DAHS or a kiln feed and a feed-to-clinker ratio?  Is the DAHS vendor expecting that any kiln feed-to-clinker ratio be applied “outside the DAHS”?

We discussed the potential expectations that the DAHS vendor may have of you, but what expectation should you have of them?  Your DAHS vendor should provide you a document describing the data validation and data averaging processes that are being used.  How are they building a 30-day average? How many minutes are needed to establish a valid 180-minute rolling average after the raw mill operational status changes from off to on or vice-versa?  Are calculated averages corrected to 7% O2 on the minute or hourly basis? How many minutes in startup/shutdown are needed in an hour to designate that hour as startup/shutdown (remember that startup/shutdown hours are excluded from compliance averages)?  Why would you need to know this?  The DAHS vendor is part of your team to develop a compliance approach for the PC MACT.  There may be no right or wrong way to interpret the “grey areas” of data validation within the PC MACT.  The plant must understand the advantages and disadvantages to the data validation process when building compliance averages.  We recommend that the data handling be addressed in the site-specific monitoring plan required by the PC MACT.  Don’t worry we’ve got you covered here as well.  Be on the lookout for an upcoming blog post that focuses on the elements and importance of a site-specific monitoring plan.

You may be thinking that this blog post raises a lot of questions and does not provide many answers.  It does, and I am not done yet.  How will the DAHS handle measurements of HCl in excess of the span value and the potential missing data substitution required for those periods?  What about the reports required to be submitted via Compliance and Emissions Data Reporting Interface (CEDRI)?  Is your DAHS vendor tracking any reporting format updates released by U.S. EPA?  We hope that this blog post has got you thinking.  These are all serious questions with serious compliance implications.  Your solution may not be any one answer to the above questions, but may be part of an overall compliance strategy that addresses all of the above questions. 

Stay tuned for upcoming blog posts that will continue to dive further into the PC MACT.  Can’t wait?  We know…that deadline is right around the corner.  Here’s how we are helping other clients prepare for PC MACT right now: reviewing the plant’s proposed compliance approach, identifying operational considerations, identifying gaps, and preparing a site-specific monitoring strategy to resolve outstanding implementation items.  Give me a call or shoot me an email and we’ll get started.  


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