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“Your Safer Source for Science” Chemical Disposal Procedures Review of Chemical Disposal Procedures, continued
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As an example of this strategy, some experiments or demonstra- tions, such as the iodine clock reaction, may produce small amounts of iodine as a byproduct. Incorporate reduction of the iodine, an oxidizer, at the conclusion of the experiment. (Halogens may be reduced with sodium thiosulfate according to Flinn Suggested Disposal Method #12a.) In reviewing this treatment method, make sure you know the balanced chemical equation so that the appropriate molar excess of reducing agent, as well as any acid or base needed for the reaction, will be used.
Reducing the Amount and
Toxicity of Hazardous Waste
Not all potentially hazardous waste must be shipped off-site for treat- ment or disposal. EPA and many states provide several regulatory exclusions that allow generators to treat hazardous waste without a permit as part of a broader mandate to further waste reduction efforts. In its publication “Little Known but Allowable Ways to Deal with Hazardous Waste,” published in 2000, the EPA describes five strate- gies for minimizing hazardous waste. These include the domestic sewage exclusion, elementary neutralization, recycling, treatment in accumulation containers, and burning in small boilers. Recall that each state sets its own requirements for compliance with RCRA regulations. Requirements cannot be less strict than federal law, but states may impose more limitations than federal law. Thus, 28 states allow treat- ment in accumulation containers, two prohibit it, and the others impose some conditions or restrictions on treatment methods. (A complete state-by-state listing of all allowable waste reduction strategies can be found in the Appendix to the EPA publication cited above.)
Source reduction, or pollution prevention, is the preferred method for reducing the environmental burden of hazardous wastes. Materials may also be reclaimed by processing them to recover useful products. When source reduction and reuse or recycling are not feasible, waste may be treated to reduce its volume and toxicity. EPA allows drain disposal of even hazardous wastes via the “domestic sewage exclusion” provided that amounts and chemicals are in compliance with all wastewater standards and discharge limits imposed by publicly owned water treat- ment works. Among the allowed chemical treatments are elementary neutralization of acids and bases, precipitating metals from solution to obtain insoluble salts, and oxidation–reduction reactions. Treatment residues may still require management as a hazardous waste and resi- dues destined for land disposal are subject to land disposal restriction standards. Never dispose of chemicals in a septic system or storm sewer. Make sure chemicals will not react with piping systems, and do not specifically rely on dilution to reduce the reactivity of chemicals or render them nonhazardous.
Licensed Hazardous Waste Disposal
Some chemicals will always require licensed hazardous waste disposal. These include toxic heavy metal salts and their solutions, including mercury, lead, cadmium, and chromium; arsenic and its compounds; halogenated organic solvents such as methylene chloride, chloroform, trichloroethylene or perchloroethylene; and various pesticides.
Summary
Most schools and many small colleges will fall into the least regulated “conditionally exempt small quantity generator” class for complying with EPA regulations regarding the storage and disposal of hazardous waste. However, it is important to know your status. It is the responsi- bility of every school to identify all types of hazardous waste that they generate. Hazardous waste generally falls into two categories, charac- teristic wastes and listed wastes. An accurate and up-to-date chemical inventory is the most effective means of keeping track of all chemi- cals and thus preventing the accumulation of unused chemicals that will need to be discarded. This is especially important for discarded chemicals that would be designated as P-list, or acutely toxic, hazard- ous waste. Of the more than 1200 chemicals that Flinn Scientific sells,
only six chemicals are on the P-list. Laboratory chemicals or chemical byproducts are not generally considered to be waste until they have left the lab. To avoid restrictions on treating hazardous waste, always incorporate treatment of excess chemicals or chemical byproducts from a lab activity into the lab procedure itself. Please consult this Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state, and local regulations that may apply, before proceeding. In its effort to reduce the amount and toxicity of hazardous waste, the EPA provides several exclusions for the treatment of hazardous waste without a permit. Not all states, however, allow all of these procedures. Among the generally allowed treatment methods are acid–base neutralization reactions, oxida- tion–reduction reactions, and precipitating metals to obtain insoluble salts. Some chemicals will always require licensed hazardous waste disposal. Please call or e-mail Flinn Scientific if you have any ques- tions or if we can offer additional assistance.
Review of Chemical Disposal Procedures
The administration, faculty, and staff share responsibility for minimiz- ing the amount of hazardous waste and disposing of those wastes in a way that safeguards human health, protects the environment, and complies with all relevant environmental laws and regulations.
It is suggested that regular safety meetings are conducted. The discussion period will vary depending on the issues that need to be addressed.
It is important to keep a copy of safety training notes and a signed attendance sheet to verify that regular safety training meetings were held. The sign-up sheet is almost as important as the training notes and is usually the first thing that is requested and reviewed by regulatory inspectors. A copy of the sign-up sheet that we suggest using may be found at www.flinnsci.com/forms/signup.aspx.
References
1. “Hazardous Waste Management for School Laboratories and Classrooms,” EPA Publication 908-F-06-001, February 2006. Available online (accessed August 2015)
2. “Chemical Management Resource Guide for School Administrators,” EPA Publication 747-R-06-002, December 2006. Available online (accessed August 2015)
3. “Little Known but Allowable Ways to Deal with Hazardous Waste,” EPA Publication 233-B-00-002, May 2000. Available online (accessed August 2015)
4. ACS Task Force on Laboratory Waste Management; Laboratory Waste Management: A Guidebook; American Chemical Society: Washington, DC (2012).
5. Margaret-Ann Armour, Hazardous Laboratory Chemicals Disposal Guide, Third Edition; CRC Press, Lewis Publishers: Boca Raton, FL (2003).
6. National Research Council; Prudent Practices in the Laboratory: Handling and Management of Chemical Hazards; National Academies Press: Washington, D.C. (2011).