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Subpart AA Standards
Closed-Vent Systems
Control Devices
Waste Determinations
Recordkeeping Requirements
Reporting Requirements
Implementation Issues Associated with Subpart AA Regulations
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Subpart AA Standards
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These regulations apply to process vents associated with
distillation, fractionation, thin-film evaporation, solvent
extraction or air or steam stripping operations that manage
hazardous wastes with organic concentrations of at least 10
ppmw. The owner or operator with process vents associated
with one of the processes above must reduce total organic
emissions from affected process vents at the facility below 1.4
kg/h (3 lb/h) and 2.8 Mg/yr (3.1 tons/yr) or reduce, by use of a
control device, total organic emissions from all affected process
vents at the facility by 95 weight percent. |
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Closed-Vent Systems
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| Closed-Vent Systems |
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Description: A closed-vent system is defined as a system that is not open to
the atmosphere and that is composed of piping, connections,
and, if necessary, flow-inducing devices that transport gas or
vapor from a piece or pieces of equipment to a control device. |
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Control Devices
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| Control Devices |
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Description: The following are descriptions of the control device
requirements included in the Subpart AA standards. These
control devices must be installed, calibrated, maintained and
operated according to the manufacturers specifications. They
also must be operating at all times when emissions may be
vented to them. |
| Vapor Recovery Devices Such as Condensers and Carbon Absorption Systems |
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Description: A control device involving vapor recovery must be designed
and operated to recover the organic vapors vented to it with an
efficiency of 95 weight percent or greater. This requirement
must be maintained unless the total organic emission for all of
the affected process vents at the facility can be maintained at
less that 1.4 kg/h and 2.8 Mg/yr if the vapor recovery device is
operating at an efficiency less than 95 weight percent. |
| Flares |
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Description: A flare used to comply with the Subpart AA regulations can be
steam-assisted, air-assisted or nonassisted. A flare must be
designed for and operated with no visible emissions as
determined by Method 22 which is found in 40 CFR Appendix
A. |
| Enclosed Combustion Devices |
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Description: Examples of enclosed combustion devices include thermal
vapor incinerator, catalytic vapor incinerator, boiler and process
heater. |
| Other Control Devices |
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Description: Control devices other than thermal vapor incinerators,
catalytic vapor incinerators, flares, boilers, process heaters,
condensers, or carbon adsorption systems also may be used to
destroy organics from process vents that are subject to the
Subpart AA standards. |
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Waste Determinations
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| Waste Determination to Determine Applicability of Subpart AA Standards |
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Description: In order to show that a process vent associated with a
hazardous waste distillation, fractionation, thin-film evaporation,
solvent extraction, or air or steam stripping operation is not
subject to the Subpart AA standards, the owner or operator
must make an initial determination that the time-weighted,
annual average total organic concentration of the waste
managed by the waste management unit is less than 10 ppmw.
The owner or operator may use either direct measurement or
process knowledge. |
| Demonstrating Compliance with Performance Standards |
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Description: Determinations of process vent emissions and reductions of
total organic compound concentrations achieved by control
devices may be based on engineering calculations or
performance tests. If performance tests are used to determine
total organic compound concentrations, vent emissions, or
emission reductions, the performance tests must conform with
the requirements outlined in 40 CFR 264.1034 and 265.1034. |
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Recordkeeping Requirements
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| Recordkeeping Requirements |
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Description: Records must be kept which identify all affected process vents
and provide data and information on the annual throughput and
operating hours of each affected unit, estimated emission rates
for each affected vent, estimated emission rates for the overall
facility and the approximate location of each vent within the
facility. |
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Reporting Requirements
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| Reporting Requirements |
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Description: Reporting requirements exist for permitted facilities which are
subject to Subpart AA standards. A semiannual report which
identifies the facility by EPA identification number, facility name,
and facility address must be submitted to the Regional
Administrator. |
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Implementation Issues Associated with Subpart AA Regulations
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| Implementation Issues Associated with the Subpart AA Regulations |
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Description: Subpart AA applies specifically to process vents associated
with distillation, fractionation, thin-film evaporation, solvent
extraction, or air/steam stripping operations subject to a permit.
Because of the recycling provisions, operations such as the
distillation of hazardous waste at generator facilities are
generally exempt from permitting, with the practical effect that
Subpart AA is generally only applicable at TSD facilities. While
the applicability of Subpart AA is limited, it is important to note
that subsequent requirements of Subparts BB and CC refer
back to the control device standards of Subpart AA. |
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