Waste disposal, toxic laboratories

Those elements of conventional laboratory design that must be refined for facilities in which toxic chemicals will be handled are presented. Alarms, communications, construction materials, containment cabinets, filter systems, floor plans, security, compressed gases, and waste disposal are discussed. Emphasis is given to design considerations dictated by the use of large numbers of fume hoods. 

Armour, M.A., Laboratory methods for disposal of toxic inorganic and organic chemicals, in Hazardous Waste Control in Research and Education, Pollution Prevention and Waste Minimization in Laboratories, Reinhardt, P.A. etal., Eds., Lewis Publishers, Boca Raton, FL, 1995, p. 105 Haz. Mat. Spills Tec., 29.7. 

Armour, M.A., Browne, L.M., and Weir, G.L., J. Chem. Educ., 62, A93,1985 Armour, M.A., J. Chem. Educ., 65, A64, 1988 Armour, M.A., Laboratory methods for disposal of toxic inorganic and organic chemicals, in Hazardous Waste Control in Research and Education, Korenaga, T. etal., Eds., Lewis Publishers, Boca Raton, FL, 1994, p. 101 Armour, M.A., Chemical treatment methods to minimize waste, in Pollution Prevention and Waste Minimization in Laboratories, Reinhardt, P.A. et al., Eds., Lewis Publishers, Boca Raton, FL, 1995, p. 289. 

An account of the safe disposal of laboratory chemicals is given in Pitt, M. J., et al., Handbook of Laboratory Waste Disposal (Chichester Ellis Horwood, 1985). Detailed experimental procedures have been published on how to convert particularly reactive and toxic substances into less harmful products before their disposal see, for example. Hazardous Laboratory Chemicals Disposal Guide, 3rd ed., ed. M.-A. Armour (Boca Raton, FL CRC Press, 2003). Destruction of Hazardous Chemicals in the Laboratory, 2nd ed., ed. G. Lunn et al. (New York Wiley, 1994) contains methods for the degradation and disposal of the following chemicals ... 

Disposal of toxic wastes like acetonitrile is expensive. Generally, there are limits on how much waste can be stored on-site, putting constraints on waste generation. Small laboratories generally collect waste and periodically have a disposal/reclaimation company haul it away. There is usually a fee for coming and an additional fee that depends on the nature and quantity of waste. In many locations, waste disposal is more expensive than the solvent purchase price. 

In laboratory, small amounts of metal alkyls may be destroyed by diluting the pure compounds or its more concentrated solutions to a concentration below 5% with a hydrocarbon solvent, such as hexane or toluene. Alternatively, a water-miscible solvent, such as ethanol or ferf-butanol may be used. Small volumes of such solutions are then slowly and cautiously added to water in wide-mouthed containers in a hood and swirled gently. The metal alkyls are converted into their oxides or hydroxides. The organic solvent, if immiscible in water, is separated and evaporated in a hood. The entire content may, alternatively, be placed in waste containers and labeled for disposal. The toxic oxides or hydroxides of the metals formed are disposed for landfill burial while the nontoxic metal oxides or hydroxides conld be flushed down the drain. Alternatively, the metal alkyl solution or its waste may be diluted to a concentration below 5% with toluene or heptane. The diluted solution is then placed in a labeled container under argon for waste disposal. 

Until a few years ago landfill disposal has been the favored method of disposing of laboratory wastes. Because of potential problems such as damage to the incinerators and control of toxic emissions and hazardous constituents in the residual ash due to the variety of materials in mixed laboratory wastes, many incineration facihties did not wish to accept this category of materials, allhough some would accept properly segregated materials. In addition. 

In spite of this capacity, many t)q)es of laboratory mixed waste have no commercial repository. No commercial mixed waste disposal facilities exist for waste contaminated with most toxic metals (such as mercury) or for lead-contaminated oils. Commercial disposal capacity likewise does not exist for high concentrations of halogen-containing organics and other TCLP waste, such as waste that contains chloroform. 

Waste disposal Assure that the plan for each laboratory operation includes plans and training for waste disposal (230). Deposit chemical waste in appropriately labeled receptacles and follow all other waste disposal procedures of the Chemical Hygiene Plan (22, 24). Do not discharge to the sewer concentrated acids or bases (231) highly toxic, malodorous, or lachrymatory substances (231) or any substances which might interfere with the biological activity of waste water treatment plants, create fire or explosion hazards, cause structural damage or obstruct flow (242). 

Special waste or hazardous waste is waste which meets the hazard criteria defined in the Special Waste Regulations 1996. The material can be described as dangerous, hazardous, or toxic waste. Because of the hazards of special waste the Regulations require that movement of such waste is tracked from source to final disposal by means of a consignment note system. Examples of Special Waste are asbestos, waste from a laboratory or waste from a hospital. 

Chemical Toxicity. In chemistry courses students learn a lot about what a chemical can do for them, but they know woefully little about what a chemical can do to them This deficiency in their chemical education is a result of standard and currently recommended academic practices. (For example, almost all new laboratory manuals in general and organic chemistry have eliminated the use of benzene and dichromate because of their carcinogenic status.) For reasons of safety and economy teaching laboratories tend to make use of small amounts of reagents with minimum toxicity, and use low-risk procedures, such as microscale. Students have only a single or at most a few exposures to any one chemical, and learning about a chemical s toxicity is minimal. These procedures often continue into advanced courses, and even research projects. Spills and waste disposal are handled by the instructors. 

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