Question: How should you dispose of an absorbent that soaked up acid?
Answer: Absorbents take on the properties of the substances they absorb, so you would need to handle the mat as you would the acid itself.
Under Resource Conservation and Recovery Act (RCRA) regulations, facilities that generate wastes must first determine if the waste is a solid and then if the waste is hazardous before disposal. Wastes are hazardous if they are an Environmental Protection Agency (EPA) listed waste or have a hazardous characteristic (ignitable, corrosive, reactive or toxic). If the acid is considered hazardous due to federal, state or local regulations, then it always needs to be handled as hazardous waste.
This doesn’t always mean that acid-soaked absorbents need to be landfilled. Most absorbents can be recycled through fuels blending processes that thermally destroy the absorbent to create energy.