TITLE 326 AIR POLLUTION CONTROL BOARD

Amends 326 IAC 1-2-2.5 and 326 IAC 4-1-7 concerning refractory-lined box type air curtain destructors. Effective 30 days after filing with the Publisher.

First Notice of Comment Period: June 1, 2011, Indiana Register (DIN: 20110601-IR-326110317FNA).

Second Notice of Comment Period: November 16, 2011, Indiana Register (DIN: 20111116-IR-326110317SNA).

Notice of First Hearing: November 16, 2011, Indiana Register (DIN: 20111116-IR-326110317PHA).

Change in Notice of Public Hearing: December 21, 2011, Indiana Register (DIN: 20111221-IR-326110317CHA).

Change in Notice of Public Hearing: March 7, 2012, Indiana Register (DIN: 20120307-IR-326110317CHA).

Date of First Hearing: May 2, 2012.

IC 13-14-9-4.5 states that a board may not adopt a rule under IC 13-14-9 that is substantively different from the draft rule published under IC 13-14-9-4 until the board has conducted a third comment period that is at least 21 days long. Because this proposed rule is not substantively different from the draft rule published on November 16, 2011, at DIN: 20111116-IR-326110317SNA, the Indiana Department of Environmental Management (IDEM) is not requesting additional comment on this proposed rule.

IDEM requested public comment from November 16, 2011, through December 16, 2011, on IDEM's draft rule language. IDEM received comments from the following parties:

Air Burners, LLC (AB)

Following is a summary of the comments received and IDEM's responses thereto:

Comment: 326 IAC 4-1-7(a)(5) reads as if an air curtain burner (destructor) can't be located at either a landfill or transfer station. The commenter suggests that the "1,000 foot rule" might better read "when located at a landfill or transfer station the air curtain burner (destructor) will be located 1,000 feet from any combustible source material." One of the advantages of the air curtain burner in addition to its pollution control properties is the fact that it reduces dependence on landfills for the disposal of woody debris. This extends the landfill life and reduces gas releases from decomposing wood waste rotting in the landfill, including methane, a very undesirable greenhouse gas. (AB)

Response: The purpose for not allowing the operation of an air curtain destructor at or near a landfill is to prevent the possibility of igniting an underground fire fueled by either the buried waste or the gases produced by the buried waste. The air curtain destructor is not intended to be permanently located at a site. It is intended to be located at a job site to dispose of the clean wood waste or vegetation derived from clearing a specific project site. Approval to operate an air curtain destructor at a specific job site is not valid for more than one year. Operating an air curtain destructor at a specific job site, for disposal of clean wood waste or vegetation derived from that site, eliminates the need to haul this waste to either a transfer station or landfill for disposal. Windrowing, mulching, chipping, and salvaging marketable material are alternatives to burning. In addition, tree waste may be placed in ponds or lakes for fish habitat provided this method complies with other local, state, and federal requirements. In summary, the operation of an air curtain destructor at a transfer station or landfill is prohibited because of fire hazard, operating time is limited, and there are other methods of disposal which would prevent the material from going to a landfill while being environmentally acceptable.

Comment: The commenter suggests deleting the specifications for minimum average air velocity and air flow at the nozzles at 326 IAC 4-1-7(a)(11)(D) of the draft rule language in the Second Notice of Public Comment Period, because the trench burner's (or the above ground air curtain burner's) adequate performance should be gauged by opacity and/or particulate matter (PM) measurement which are indicators of the pollution control effectiveness of the machine, the purpose of using and regulating the air curtain burner in the first place. (AB)

Response: Minimum velocity and air flow were established in order that the unit would operate at 0% opacity and ensure minimal or no PM emissions. The unit creates a curtain of air passing over the burning material striking the opposite wall so that the air tumbles downward in the pit, thus, it entraps and entrains the smoke (unburned fuel) back into the burning process. The curtain of air also provides oxygen to the burning process for complete combustion of the material in the pit. Also, 326 IAC 4-1-7(a)(11)(D), (326 IAC 4-1-7(a)(12)(D) in the draft rule), applies to pit burners, not above ground units. Above ground units are regulated under 326 IAC 4-1-7(13) of the draft rule in which IDEM is proposing that the unit be operated according to the manufacturer's specifications and recommendations. In summary, requiring a minimum velocity and air flow eliminates opacity and PM emission issues.

Comment: It should be IDEM's best interest to permit and regulate machines based on newer technologies that may drastically reduce fuel consumption, PM (black carbon) and non-biogenic carbon dioxide (CO₂) emissions from the unit's diesel engine by downsizing the engines. By mandating very specific design parameters you may limit Indiana to old technology. (AB)

Response: IDEM supports new technologies that have been proven to better safeguard the environment and health of its citizens. As new technologies to control air emissions become available, IDEM takes appropriate actions to incorporate them into the regulatory process. The size and type of engine used to operate an air curtain destructor may be one factor in achieving the acceptable velocity and air flow; however, it has been reported that the pitch of the fan blades have been found to be a critical factor in achieving increased velocity. On the other hand, if a "squirrel cage" is used, you can only increase velocity by turning the "squirrel cage" faster (i.e., increasing motor speed). In this rulemaking IDEM is proposing that newly designed above ground self-contained metal box type units are required to follow manufacturer's recommendations instead of design parameters specified in the rule.

Comment: The commenter suggests deleting the specification at 326 IAC 4-1-7(a)(11)(I) of the draft rule language in the Second Notice of Public Comment that all nozzles must be aligned such that the air strikes the opposite trench wall three feet from the top edge or below. The air flow angle is important in reducing PM release and measuring the true air curtain angle is an elaborate process that cannot be accomplished accurately in the field. (AB)

Response: The air curtain destructor is positioned at the top edge of the pit (whether dug into the ground or metal fabrication) so that the nozzles are directed towards the opposite wall. Since the nozzles are stationary, they should be positioned during the manufacture of the unit so that when the unit is on flat, level ground, the nozzles are positioned such that air flow would strike the opposite wall (when positioned on site) three feet below the grade upon which the unit is located. When the pit is dug, the unit may be lifted or lowered from the rear to achieve the acceptable angle of air flow. This angle is easier to achieve when using a metal fabricated pit with an air curtain since topography would not be as critical as when digging a pit. When fabricating the metal pit, the air curtain should be positioned (when operating) to comply with all parameters. In summary, measuring the angle is not an elaborate process since this can be accomplished during the manufacturing of the metal pit and unit. The correct angle can be achieved when using an earthen pit by adjusting the height of the rear of the unit. Also, 326 IAC 4-1-7(a)(11), (326 IAC 4-1-7(a)(12) in the draft rule), applies to pit burners, not above ground units. Above ground units are regulated under 326 IAC 4-1-7(13) of the draft rule in which IDEM is proposing that the unit be aligned and directed toward the opposite wall so that the air strikes the opposite wall without the three foot from the top edge requirement.

Comment: The air curtain angle needs to be measured at the center of the nozzle jet stream. With the proper measurements, a "3 foot" requirement is wrong and will cause the ash bed to be fluidized with the resulting PM release rising significantly. If the manufacturer designs the air curtain correctly and the air curtain angle correctly, the opacity will be less than 10% and the PM release will be equally low. An acceptable PM emissions factor would be 2 pounds of PM releases per 1 ton of wood waste combusted. Other states, such as Florida, are guided by this emissions factor. (AB)

Response: If the pit is dug properly, the air curtain is properly positioned, and the nozzles are in alignment, all measurements along the nozzle action should ensure that the air strikes the opposite wall at the required three feet location. The manufacturer's design of the air curtain will ensure compliance with all required parameters such as velocity, air flow, etc. Issues with the fluidization of the ash bed have not been observed during the operation of air curtain destructors in Indiana; however, should future, reliable and valid test data prove otherwise, IDEM will take appropriate action. In summary, the parameters established in the air curtain destructor rule for pit units remain acceptable.

On May 2, 2012, the Air Pollution Control Board (board) conducted the first public hearing/board meeting concerning the development of amendments to 326 IAC 1-2-2.5 and 326 IAC 4-1-7. No comments were made at the first hearing.

SECTION 1. 326 IAC 1-2-2.5 IS AMENDED TO READ AS FOLLOWS:

Affected: IC 4-21.5; IC 13-12; IC 13-17-9

Sec. 2.5. "Air curtain destructor" means an engineered apparatus consisting of a motorized high-velocity fan and an air distribution system designed to aid in the efficient combustion of materials placed in an adjacent earthen pit or refractory lined box. An air curtain destructor is not considered an incinerator as defined in section 34 of this rule.

SECTION 2. 326 IAC 4-1-7 IS AMENDED TO READ AS FOLLOWS:

Affected: IC 4-21.5; IC 13-12; IC 13-17-9

Sec. 7. (a) To obtain an air curtain destructor letter of approval, the owner or operator shall ensure that installation and operation of such the air curtain destructor will comply with subdivisions (1) through (22) as follows. (13). Burning shall be terminated immediately at any air curtain destructor site that does not comply with this section and the following requirements:

(b) An air curtain destructor letter of approval shall be valid for no not longer than one (1) year.

(c) The commissioner or the commissioner's designated agent may add conditions to an air curtain destructor letter of approval as necessary to prevent a public nuisance or protect the public health.

(d) A decision on the air curtain destructor letter of approval is subject to IC 4-21.5 (Administrative Orders and Procedures Act (AOPA)).

*This document is incorporated by reference and is available from the Government Printing Office, 732 North Capitol Avenue NW, Washington, D.C. 20401 or is available for review and copying at the Indiana Department of Environmental Management, Office of Air Quality, Indiana Government Center North, Tenth Floor, 100 North Senate Avenue, Indianapolis, Indiana 46204.

Notice of Public Hearing

DIN: 20120530-IR-326110317PRA

Composed: Apr 26,2024 3:56:59AM EDT

A PDF version of this document.