Find a Solvent Alternative
Find out if there is an aqueous or semi-aqueous cleaner you can use instead of the solvent. This can eliminate solvent wastes and the toxicity of used shop towels altogether.
Consider using solvents that are not chlorinated and have low volatile organic compound emissions; consult material safety data sheet information for toxicity and volatility data. Good resources for solvent substitutes are your state regulatory agency and pollution prevention (P2) programs.
Minimize Solvent Use
If you can’t find an alternative, try reducing what you do use. For example, use a container that delivers fresh solvent by hand-pumping or spraying the shop towels, instead of dipping or soaking them in buckets. The container should have a secure lid to prevent the operators from rinsing shop towels in the fresh solvent, and limit evaporation. An open container of solvent can evaporate at the rate of 1 gallon every 2 days in a dry environment.
Dirty shop towels can be wrung out over a waste solvent container. This option may require that the shop towels be changed more frequently if the rinsing step is eliminated.
Need an answer fast? Relax. Our editors guarantee a personalized response to your questions within 3 business days. Take a free trial of Enviro.BLR.com and see what everyone is talking about. For a limited time, also receive the new free special report: 2011-2012 EHS Salary Guide. Download Your Free Report
Minimize Shop Towel Use
Reduce the amount of contaminated shop towels generated by:
- Using a rag to its full absorbent capacity. Partially used shop towels should be stored separately and labeled for reuse prior to laundering.
- Implementing a rag reuse system to reduce unnecessary laundering. For example, use three containers marked "clean," "reusable," and "dirty" in the rag storage area to encourage workers to reuse shop towels.
Recycle Solvents
Generators who reuse and launder their own shop towels must remove all excess solvents from the shop towels prior to storing and laundering them. The excess solvents must then be managed as hazardous wastes. Businesses can recover spent solvents through the use of an outside recycler, or recycle solvents on-site using their own equipment. Note that most state policies specify strict requirements for laundering facilities.
Excess solvents can be removed by a gravity drain, a wringer, or a centrifugal extractor prior to shipping. Some states now require this solvent-removal step. Use caution in doing this, as the solvents used may be ignitable or flammable. Extractors must be explosion proof.
Reuse in two-stage cleaning. The recovered solvent can be reused for cleaning, reducing both the amount of solvent that must be purchased and air emissions. Some specialty cleaning solvents can cost well over $12 per gallon; recovery and reuse can save money. Often this "dirty" recovered solvent can be used, for example, to pre-clean very dirty ink-laden parts; clean solvent can be used for final cleaning.
Forget expensive calls to lawyers and consultants. With Enviro.BLR.com, you get instant access, 24/7. Try it out today and get the 2011-2012 EHS Salary Guide, absolutely free. Download Your Free Report
Using solvent in two-stage cleaning can reduce new solvent usage by up to 50 percent and cost nothing to implement. Recovered solvent can also be used initially for parts washing, recaptured, then distilled for reuse or sent out for fuel blending.
Recovery through filtration and distillation. When used solvent becomes too dirty to use for any type of cleaning, distillation or filtration can be used to recover clean solvent from the dirty solvent. Small solvent stills to handle as little as 1 gallon can be purchased to recover solvent; all distillation equipment must be explosion proof.
Cleaning solvents can also be used in parts washer sinks; many of these are equipped with filters. Filter-type solvent sinks are also very good at extending the useful life of solvents.