If, after you have followed all Pollution Prevention principles, you find that you must continue to use solvents that produce dangerous wastes, you may want to recycle your spent solvent through on-site distillation by purchasing a solvent still.
Pollution Prevention Saves Solvents and Money offers ways to use less. If you can reduce the amount of spent solvents you generate, a still may not be necessary.
Choose the Right Still offers guidance on this important purchase.
Free Labels for Spent Solvent and other dangerous and recyclable wastes.
Businesses that do on-site solvent recycling must consider spent solvents to be dangerous waste when these are stored or accumulated prior to distillation. Because solvents are often reclaimed and reused multiple times, however, it is only necessary to officially "count" the largest amount of spent solvent that was accumulated at one time, prior to recycling during that month. The main reasons for counting these wastes are to determine your generator status for the month and to report the combined monthly amount on the Dangerous Waste Annual Report.
Small on-site recyclers of dangerous solvents can claim their exemptions by keeping good records. Count the greatest amount of spent solvent not yet recycled for any given month, and count all still bottoms. Small quantity generators probably do not have to report solvent-recycling activity to Ecology. However, they should keep records to prove their generator status, since the inspector will likely ask for these.
Even if a solvent still is dry much of the time, remember that it sometimes contains dangerous liquids. Solvent stills should be in secondary containment to prevent local contamination.
On-site Distillation is an Ecology publication that details distillation issues. It includes worksheets and cost-benefit analysis.
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.htm