AQ_F_1900015_20190318_CMPL_Fac-Ltr

arauco 985 Corinth Road
Moncure,North Carolina 27559
Tel:[phone]
Toll Free:855-427-2826
NC Dept of Environmental QualityFax:919-545 5822
MAR 18 2019
March 15, 2019
Raleigh Regional Office
Ray Stewart
NC Department of Environmental Quality
Division of Air Quality
Raleigh Regional Office
3800 Barrett Drive
Raleigh, NC 27609
Subject: Medium Density Fiberboard Biofilter Operations
Facility ID No. 1900015/Permit No. 03449T50
Arauco North America, Inc.
Moncure, Chatham County, North Carolina
Dear Mr.Stewart:
Arauco North America, Inc. (Arauco) is submitting this letter to the Division of Air Quality per discussions
on March 8, 2019 relating to the current and future state of the Medium Density Fiberboard (MDF)
biofilter control device (ID CD-18).The biofilter is a control device used to comply with the Plywood and
Composite Wood Products Manufacture (PCWP) MACT rule by destroying Hazardous Air Pollutants
(HAPs).Arauco implemented the biofilter to replace the previous PCWP MACT control device,the PGT
system, by entering in to SOC 2015-002 with the North Carolina Department of Environmental Quality
(NCDEQ) on November 2, 2015. Since entering SOC 2015-002, these significant deadlines have been
achieved:
• Complete the press duct work rerouting within 180 days after execution of this Order on
November 24, 2015
• Arauco filed with the DAQ an application for a revised permit for the installation of a biofilter on
January 9, 2016
• Arauco signed contracts with biofilter vendor on December 20, 2016.
• Arauco commenced construction of biofilter on February 17, 2017.
• Arauco completed construction on February 6, 2018.
• Arauco conducted performance testing on June 13, 2018 and submitted the PCWP MACT Notice
of Compliance Status on August 10, 2018.
In sum, every deadline in the SOC was met by or prior to the required date.
Arauco NA has conducted two performance tests on the Biofilter since construction was completed and
obtained the following results:

Test Date Formaldehyde Destruction Methanol Destruction
June 13,2018 97% 20%
November 8, 2018 97% 29%
During the engineering evaluation, shakedown, and compliance testing phase,Arauco had to restart the
unit multiple times before being satisfied biological growth was sufficient for the biofilter to fully
operate. As a part of the startup process, Arauco had to adjust several factors to achieve sufficient
biological growth.These included eliminating the Urea injection for 30 days with a Deferral of
Enforcement issued by the DAQ, slowly increasing the fan speed to increase the emission loading to the
unit, and adding bacteria from different sources to diversify the biological population.
In order to improve the performance and reliability of the biofilter, physical internal and external
modifications must be made to the unit including a total shutdown of the process and a subsequent
slow ramp up in order to assure improved biological activity and biofilter performance.These steps and
modifications will require time to adjust and optimize biofilter performance.
In order to provide the time needed for this improvement program,Arauco believes the best approach
is to enter in-to another SOC to accomplish the improvement program described above. There will be
potential deviations with Arauco's current Air Quality Permit No.03449T50. This would include
bypassing the biofilter for a period of time in order to accomplish a slow start up, necessitating turning
off the Urea Injection System. Good performance of the biofilter was observed when the urea injection
system was turned off during one of the initial startups. However,turning off the system could
potentially cause permit deviations from conditions 2.1.C.6.d, 2.2.B.1.a.1, and 2.2.B.1.d. In addition to
these urea injection requirements, Arauco is not confident the unit can achieve 50% DRE of WPP1 VOC
required by 2.2.B.2.a unless physical modifications internal and external to the biofilter are undertaken
to increase the biofilter's destruction efficiency.
Arauco has made a major investment, approximately$6 million, in the biofilter unit to comply with all
applicable requirements, and to reduce pollution to the environment by choosing a device that does
not generate additional NOx or greenhouse gases as would be the case with incineration-based
technologies.Since the biofilter is based on living organisms,sufficient time will be required to modify
the unit and allow the biology to regrow to stable populations. This biofilter is also unique in that it
operates at thermophilic temperatures(>1407). Consequently,several days are required to shut down
and cooldown the unit in order for technicians to safely enter the device for modifications.
By entering in to a new SOC and increasing the reliability and destruction efficiency of the biofilter,
Arauco has the primary goal of achieving a higher level of confidence in the biofilter's compliant
operation.
We look forward to further discussing this matter with you. If you have any questions, please contact
Yvonne Couts, Moncure Environmental Manager,919-545-5848 and/or [e-mail].
Sincerely,
1Ott`Bird
Corporate Environmental Manager
CC:Jeff McMillian, Moncure Plant Manager
Rich Weber, EHS&S Director