AQ_F_1900015_20190628_CMPL_Fac-Ltr

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BURNS, DAY & PRESNELL, P. A.
ATTORNEYS AT LAW
2626 GLENWOOD AVENUE, SUITE 560
RALEIGH, NORTH CAROLINA 27608
JAMES M.DAY MAILING ADDRESS:
DANIEL C.HIGGINS POST OFFICE BOX 10867
ANDREA L.HINSHAW RALEIGH,NORTH CAROLINA 27605
GREG L.HINSHAW
CI EMILY D.IVERSON TELEPHONE[phone]
JULIA Y.KIRKPATRICK FACSIMILE(919)782-2311
JAMES J.MILLS www.burnsdaypresnelI.com
LACY M.PRESNELL III-OF COUNSEL
CHARLES S.CARTER-OF COUNSEL
F.KENT BURNS—RETIRED
June 28, 2019
VIA CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. Ray Stewart, Supervisor
Raleigh Regional Office
Division of Air Quality, NCDEQ
3800 Barrett Drive
Raleigh, N.C. 27609
Re: Notice of Violation/Recommendation for Enforcement, Dated June 5, 2019
Dear Supervisor Stewart:
In response to NCDEQ's Notice of Violation to Arauco dated June 5, 2019, this letter provides the
company's responses, including the MDF biofilter concrete structure investigations and repairs, and
increases in VOC destruction efficiency.
Arauco employees visually confirmed significant biofilter concrete degradation on April 9 and
contacted DAQ about the degradation on April 10. The concrete observed during a routine outage had
shown significant acid attack and degradation around the structural concrete beams that support the
biofilter media and the walls that support the entire biofilter structure. Company representatives met with
DAQ Raleigh Regional Office staff on April 25 to discuss the concrete degradation and reduction in the
destruction efficiency of the device. During that meeting, the company representatives described the
need for significant biofilter downtime to repair the concrete and modify the device in order to increase
destruction VOC efficiency. Due to the potential for structural failure of the concrete and risks to company
employees from device failure, Arauco shut down the biofilter on May 8 and so informed DAQ by letter.
Since May 8, Arauco has worked with the biofilter original equipment manufacturer(OEM) and
subcontractors of the OEM to conduct structural analysis of the concrete structure to ensure the device is
safe to work inside and that it will not catastrophically fail while workers are inside. A subcontractor was
selected during the week of May 27 to evaluate the structure of the concrete. Core drillings and visual
inspections were performed during the week of June 3 by a subcontractor of the OEM and the preliminary
results were received by the OEM June 24.
Based on the results, Arauco and the OEM will determine a remedial course of action for cleaning
and lining the concrete interior of the biofilter with a material that is more acid and temperature resistant
than prior materials selected for the biofilter's interior liner. Arauco expects cleaning and lining of the
interior structure to begin in August. Arauco and the OEM have already met with two different concrete
lining suppliers to select a new liner material that can be applied as quickly as possible and prevent future
significant structural failures. Once a supplier is awarded the contract, two to three site mock-up
applications with different liners will be conducted to make sure the selected liner can bond correctly to
the concrete surface

Supervisor Stewart, RRO DAQ June 28, 2019
Response to NOV/NRE Page 2
Arauco has noted a lack of efficient biological activity in the device which has resulted in reduced
VOC destruction. To resolve this problem, Arauco is working with the OEM to rectify certain design errors
in the system that contribute to poor biological growth in the second half or true"biofilter" section of the
device. The media in the second half will be modified to remove the current 3 inch media and replace it
I with all 1 inch media and 1 foot of compost containing media to inoculate the unit. The OEM is working
` with Arauco and consultants from Duke University to redesign and modify the "biofilter" section in order to
reduce continuous water flow in the device to intermittent flow and significantly reduce water flow rates.
This approach should prevent washout of the true"biofilter" section which has caused the poor biological
growth. This modification will be undertaken after the interior concrete repairs are completed in the event
the irrigation systems or other components of the system need to be dismantled during the cleaning and
re-lining process of the structure. Arauco believes continuous washout that has been occurring
prevented proper biomass adherence to media and development of sufficient biomass capable of treating
the exhaust airstream for methanol and other less water soluble VOC.
Arauco is working with the same consultants at Duke University to evaluate potential biological
inhibitors present in the MDF plant's exhaust that could be inhibiting biological activity. This biological
inhibitory study was initiated during the week of June 3, with the University growing cultures at elevated
thermophilic temperatures to test with various potential inhibitory agents.
With respect to air quality impacts and mitigation, Arauco's shutdown of the biofilter on May 8tn
was undertaken to limit the time needed to evaluate and resolve the design and material problems with
the biofilter. Delaying shutdown of the device would have resulted in significant additional degradation of
the concrete structure and deterioration of the control system. The result would have been significant
additional time needed to remediate the biofilter and increased the risks to company staff from system
failure. Early shutdown of the biofilter will result in significantly shortening the downtime of the device.
While VOC emissions will increase during the shutdown, Arauco submitted modeling of the facility
prior to construction of the biofilter that demonstrated compliance with North Carolina's air toxics
standards for formaldehyde. This demonstration, showing that uncontrolled formaldehyde emissions from
the MDF dryers comply with air toxics standards for formaldehyde, was submitted to DAQ and reviewed
by Mr. Matthew Porter in October 2016.
Arauco's primary goal is expeditiously returning to full compliance with its Title V Air Permit.
Arauco has been diligently working with the OEM and outside consultants to develop the needed
corrections to repair the biofilter system and further increase its destruction efficiency. Arauco expects
that resolution of the biofilter deficiencies will ensure compliance by its Moncure facility for the long term.
Arauco proposes the following timeline to have the biofilter running and complying with permitted
rules and regulations:
• Rehabilitation Program Planning and Contract Award: 7/1/19—8/15/19
• Biofilter Construction Activities: 8/15/19— 12/1/19
• Biofilter Start-up & Commissioning: 12/1/19-1/31/20
• Biofilter Evaluation, Engineering, Shakedown and compliance testing: 2/1/20—7/31/20
If you have any questions or need any additional information regarding this any aspect of these
responses, please contact Yvonne Couts at(919) 545-5848, or me at the numbers and addresses listed
above.
Very truly yours,
Charles S. Carter
Attorney for Arauco
cc Steve Hall, DAQ
Jeff McMillian, Arauco
John Bird, Arauco
Yvonne Couts, Arauco