And the Changes Keep Coming for Pulp and Paper Mills…Proposed Subpart BBa is Out!

Just when we thought Pulp and Paper Mills could take a regulatory breather, another very important rule comes out in the proposal stage.  We have heard rumblings of a review of New Source Performance Standard (NSPS) Subpart BB since the pulp and paper Information Collection Request (ICR).  Well, it’s out now in pre-publication form.  Kraft mills may be wondering what has triggered these proposed amendments.  The answer is a combination of it being time to complete the eight (8) year review that is required by the Clean Air Act (CAA), and a lawsuit requiring U.S. EPA to complete the review.  I know you are asking yourself “Will we be affected and if so, how?” The short answer is that if you are an existing source, you will not be affected immediately.  The proposed amendments would be a new rule, 40 CFR Part 60 Subpart BBa, which would apply to new, reconstructed, or modified sources after the proposed rule is published in the Federal Register. 

The proposed new Subpart BBa would still only affect the following sources at Kraft pulp mills:

• Digester system
• Brownstock washer system
• Multiple-effect evaporator system
• Recovery furnace
• Smelt dissolving tank
• Lime kiln; and
• Condensate stripper system

No additional Kraft mill sources have been brought into the proposed rule.  The proposed rule focuses on particulate matter (PM) and total reduced sulfur (TRS).  However, U.S. EPA wants to better understand the atmospheric chemistry between nitrogen oxides (NO_X), sulfur dioxide (SO₂), and particulate matter less than 2.5 microns (PM_2.5).  Therefore, Subpart BBa proposes requiring condensable PM (CPM) stack testing, using Method 202, to develop data needed to aid in understanding of the chemistry of CPM formation even though there is no proposed limit.  The proposed PM limit is still in terms of filterable PM (FPM) demonstrated by Method 5 testing. 

The proposed limits are:

• FPM limit of 0.015 grains per dry standard cubic feet (gr/dscf) for new and reconstructed recovery furnaces, which is consistent with 40 CFR Part 63 Subpart MM.  Modified recovery furnaces would maintain the current limit of 0.044 gr/dscf.
• Opacity limit for recovery furnaces would be 20% for new, constructed, and modified sources.  U.S. EPA is also proposing to reduce the monitoring allowance from 6% to 2% of the six (6)-minute opacity averages.
• TRS limit for recovery furnaces would remain the same (5 parts per million dry volume, ppmdv, for straight and 25 ppmdv for cross).  A 1% monitoring allowance for TRS emissions to 30 ppmdv or less is proposed. 
• PM limit of 0.12 pounds per ton black liquor solids (lb/ton BLS) for new and reconstructed smelt dissolving tanks that are associated with new or reconstructed recovery furnaces.  Modified, new, or reconstructed smelt dissolving tanks not associated with a new or reconstructed recovery furnace would maintain the current limit of 0.2 lb/ton BLS.
• TRS limit of 0.033 lb/ton BLS for smelt dissolving tanks would remain the same under the proposed rule.
• PM limit of 0.064 gr/dscf (for all fuels fired) for modified lime kilns, which is consistent with 40 CFR Part 63 Subpart MM.  New or reconstructed lime kilns would be subject to a PM limit of 0.010 gr/dscf, which is also consistent with 40 CFR Part 63 Subpart MM.
• TRS limit for lime kilns would remain the same (8 ppmdv).  A 1% monitoring allowance for TRS emissions to 22 ppmdv is proposed. 
• Opacity limit of 20% (consistent with 40 CFR Part 63 Subpart MM) for lime kilns with an electrostatic precipitator (ESP) with a 1% monitoring allowance.
• TRS limit for digester systems, brownstock washer systems, evaporator systems, and condensate stripper systems remain the same as Subpart BB.

U.S. EPA is continuing the trend of removing startup, shutdown, and malfunction exclusions and requiring repeat air emissions testing.  The proposed emission limits would apply at all times (i.e. no separate limits for startup and shutdown periods).  The proposed rule would include the affirmative defense provisions for periods of malfunctions.  The proposed rule would require initial and repeat testing for PM (filterable and condensable) and TRS.  The repeat testing would be required every five (5) years.  The proposed rule would also require specific monitoring for control devices, such as ESPs and wet scrubbers.  As seen in recent rulemakings, U.S. EPA is requiring performance test data be submitted through the Compliance and Emissions Data Reporting Interface (CEDRI) in the proposed Subpart BBa.

As previously mentioned, the excess emissions during a quarter in the proposed rule would be:

• A 1% allowance for TRS emissions from recovery furnaces, provided that the TRS concentration doesn’t exceed 30 ppm corrected to 8% oxygen.
• A 2% allowance for average opacities from recovery furnaces.
• A 1% allowance for TRS emissions from lime kilns, provided that TRS concentrations doesn’t exceed 22 ppm corrected to 10% oxygen.
• A 1% allowance for average opacities from lime kilns.

Another difference from Subpart BB is the provision to consider TRS concentration uncorrected when determining compliance with excess emissions during periods of startup or shutdown when stack oxygen approaches ambient conditions.  If the measured TRS concentration uncorrected is less than the emission limit (i.e. 5 ppm for recovery furnaces and 8 ppm for lime kilns) during periods of startup or shutdown when the stack oxygen is 15% or greater, then the TRS average would be deemed in compliance.

When planning to construct, reconstruct or modify one of the affected sources at your Kraft mill, you will now add another layer of regulatory review with the need to consider the proposed Subpart BBa requirements.  So, go ahead get your thoughts together so you can provide comments because the new rule will be published any day triggering the 45-day comment period.  Put pen to paper (or in this electronic age, keyboard to computer) and let your thoughts be known to U.S. EPA!