Customer Questions: Disposing of Aerosol Puncturing Unit Filters
Question: I work for an oil and gas company. I’m looking at the aerosol can puncturing device. How do you properly dispose of the filters after they’ve been used?
Answer: When an aerosol can is punctured, any remaining propellant and liquid are evacuated from the can into the drum. Because this could cause an unsafe amount of pressure to build up in the drum, the filter that threads into the 3/4 inch bung is designed to vent at 3 psi. If this vent was solely a vent and did not have filtration media attached, VOC vapors from the propellant and mists from whatever liquid the can contained would be released into the environment.
But, because of the two-stage filtration media, both the mist and VOCs are captured. The coalescing media in the first stage of the filter collects any liquid mist that tries to escape from the drum. Capturing this mist first helps extend the life of the carbon filtration media in the second stage. The coalescing filters are designed to allow drainage of liquids back into the drum. This keeps them under the RCRA 3% “empty” rule, allowing them to be handled as non-hazardous waste.
The activated carbon media absorbs VOC vapors, leaving only the carbon and air. The EPA issued a technical bulletin discussing carbon and forms of VOC absorbents that discusses this process in great detail. The spent carbon media can also be handled as non-hazardous waste.