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Cleaning solutions
Cleaning solutions Laboratory Waste Minimization
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aboratories have numerous opportunities for waste minimization with cleaning solutions. These opportunities arise in areas such as standard operating procedures, selection of cleaning agents, and storage of used cleaning solutions. In this column, we will address some of these opportunities to assist you in making more specific assessments for your laboratory.
work just fine. In other cases, a stronger cleaning agent is required. Agents such as potassium hydroxide/ethanol, hydrochloric acid, or NoChromix are corrosive; however, most can be neutralized by elementary methods (be careful!) and disposed down the drain. Check with the local sanitary sewer authority to make sure you are in compliance with all of their requirements before disposing of neutralized cleaning solutions.
STANDARD OPERATING PROCEDURES
Before starting any work with chemicals, give thought to what equipment will require cleaning at the end of the experiment and how it will be cleaned. Perhaps the experimental conditions can be modified so that equipment does not become as contaminated when compared to the standard procedure. Perhaps the reaction conditions can be made less severe so that the equipment is easier to clean. Or, perhaps the experiment can be redesigned to reduce the amount of contaminated equipment resulting from the work. If contaminated equipment must result from the experiment, what cleaning methods will be required? Again, you should be able to answer this question before you start the experiment. When actually using cleaning agents, there may be ways of doing more with less. For example, if several rinses with acetone are required, don’t use fresh acetone each time. Use acetone from later rinses for earlier rinses the next time around. For corrosive cleaners, how many times can they be used before they must be discarded? Don’t assume that cleaners may only be useful once. Peter C. Ashbrook (left) is director of environmental health and safety at the University of Missouri-Columbia, and Todd A. Houts (right) is interim assistant director of environmental health and safety at the University of Illinois at UrbanaChampaign.
1074-9098/00/$20.00 PII S1074-9098(00)00116-7
STORAGE OF CLEANING SOLUTIONS
Store both used and unused cleaning solutions in suitable containers that are properly labeled. Provide secondary containment when appropriate. Store the containers in a location where they will not get in anyone’s way. Several years ago, the consequences of an accident involving the incomplete treatment of sodium was greatly compounded by the improper storage of acetone used for cleaning purposes. A graduate student had treated sodium with tert-butyl alcohol and poured the solution down the drain. Because the reaction had not gone to completion, a fire broke out in the sink. As it happened, there was a onegallon glass bottle of acetone used for cleaning purposes that was stored in this sink. The graduate student, realizing that a fire near acetone was dangerous, tried to remove the bottle from the sink. Unfortunately, in the haste to remove the bottle it hit the side of the sink and broke, greatly accelerating the fire and causing substantial damage to the laboratory. Think about how easily the waste from that incident could have been minimized.
SELECTION OF CLEANING AGENTS
When we were in school, chromic acid cleaning solutions were the standard cleaning agents used. Chromic acid works great, but is hazardous to work with and expensive to dispose. Even when neutralized—which is not easy— chromic acid must be disposed of as a hazardous waste because of the presence of chromium. When people think to look for an alternative to chromic acid, they discover that there are many alternatives. In many cases, simple detergents such as Alconox or Pierce RBS-35
CONCLUSION
Cleaning solutions provide many opportunities for waste minimization. Take some time to examine your procedures to see if you have some available to you. Waste Minimization Recommendation #56: If you use chromic acid, look for alternative cleaning solutions. Waste Minimization Recommendation #57: Store containers of cleaning solutions out of the way and with secondary containment, if appropriate.
© Division of Chemical Health and Safety of the American Chemical Society Published by Elsevier Science Inc.
31
L
aboratories have numerous opportunities for waste minimization with cleaning solutions. These opportunities arise in areas such as standard operating procedures, selection of cleaning agents, and storage of used cleaning solutions. In this column, we will address some of these opportunities to assist you in making more specific assessments for your laboratory.
work just fine. In other cases, a stronger cleaning agent is required. Agents such as potassium hydroxide/ethanol, hydrochloric acid, or NoChromix are corrosive; however, most can be neutralized by elementary methods (be careful!) and disposed down the drain. Check with the local sanitary sewer authority to make sure you are in compliance with all of their requirements before disposing of neutralized cleaning solutions.
STANDARD OPERATING PROCEDURES
Before starting any work with chemicals, give thought to what equipment will require cleaning at the end of the experiment and how it will be cleaned. Perhaps the experimental conditions can be modified so that equipment does not become as contaminated when compared to the standard procedure. Perhaps the reaction conditions can be made less severe so that the equipment is easier to clean. Or, perhaps the experiment can be redesigned to reduce the amount of contaminated equipment resulting from the work. If contaminated equipment must result from the experiment, what cleaning methods will be required? Again, you should be able to answer this question before you start the experiment. When actually using cleaning agents, there may be ways of doing more with less. For example, if several rinses with acetone are required, don’t use fresh acetone each time. Use acetone from later rinses for earlier rinses the next time around. For corrosive cleaners, how many times can they be used before they must be discarded? Don’t assume that cleaners may only be useful once. Peter C. Ashbrook (left) is director of environmental health and safety at the University of Missouri-Columbia, and Todd A. Houts (right) is interim assistant director of environmental health and safety at the University of Illinois at UrbanaChampaign.
1074-9098/00/$20.00 PII S1074-9098(00)00116-7
STORAGE OF CLEANING SOLUTIONS
Store both used and unused cleaning solutions in suitable containers that are properly labeled. Provide secondary containment when appropriate. Store the containers in a location where they will not get in anyone’s way. Several years ago, the consequences of an accident involving the incomplete treatment of sodium was greatly compounded by the improper storage of acetone used for cleaning purposes. A graduate student had treated sodium with tert-butyl alcohol and poured the solution down the drain. Because the reaction had not gone to completion, a fire broke out in the sink. As it happened, there was a onegallon glass bottle of acetone used for cleaning purposes that was stored in this sink. The graduate student, realizing that a fire near acetone was dangerous, tried to remove the bottle from the sink. Unfortunately, in the haste to remove the bottle it hit the side of the sink and broke, greatly accelerating the fire and causing substantial damage to the laboratory. Think about how easily the waste from that incident could have been minimized.
SELECTION OF CLEANING AGENTS
When we were in school, chromic acid cleaning solutions were the standard cleaning agents used. Chromic acid works great, but is hazardous to work with and expensive to dispose. Even when neutralized—which is not easy— chromic acid must be disposed of as a hazardous waste because of the presence of chromium. When people think to look for an alternative to chromic acid, they discover that there are many alternatives. In many cases, simple detergents such as Alconox or Pierce RBS-35
CONCLUSION
Cleaning solutions provide many opportunities for waste minimization. Take some time to examine your procedures to see if you have some available to you. Waste Minimization Recommendation #56: If you use chromic acid, look for alternative cleaning solutions. Waste Minimization Recommendation #57: Store containers of cleaning solutions out of the way and with secondary containment, if appropriate.
© Division of Chemical Health and Safety of the American Chemical Society Published by Elsevier Science Inc.
31