Air Emission Standards for Process Vents

The first set of air emission standards address the emissions of process vents. A "process vent" is any open-ended pipe or smokestack that releases emissions directly into the atmosphere or through another system or tank. Process vents are typically used with treatment technologies for hazardous wastes that generate VOCs. Some of the commonly used technologies are as follows:

• Distillation (removal of contaminants with differing boiling point through a process of heating and cooling)
• Fractionation (separation and isolation of contaminants)
• Thin-film evaporation (thermal separation of components by a mechanically generated film that is thin and turbulent causing the volatile compounds to quickly evaporate and separate from the waste)
• Solvent extraction (separation based on the different solubilities of the components of the waste)

The regulations also apply to air stripping and steam stripping operations that are used to manage hazardous wastes that have an annual total organic concentration of 10 parts per million by weight (ppmw). "Air stripping" is the process of moving air through contaminated groundwater to remove VOCs. Surface water can be similarly treated using an above-ground treatment system. "Steam stripping" refers to the process of using steam distillation to remove or separate the VOCs from waste.

Owners and operators of TSDFs who employ these methods for hazardous waste treatment must comply with the RCRA regulations, by either modifying their treatment process or installing a device that effectively controls the level of organic emissions.

To learn more about RCRA visit our RCRA Hazardous Waste Safety Online Training web page.