DISPOSING OF WASTE
1. Disposing of Waste - Teachers should be aware of the appropriate method of disposal for any chemical used in the school laboratory. When in doubt, refer to the MSDS, a disposal manual, or the source of the chemical.
a. Classification of Hazardous Waste
The Environmental Protection Agency classifies wastes as:
Ignitable: has a flash point below 140°C, is an oxidizer, or is an ignitable compressed gas. Corrosive: has a pH equal to or below 2.0 or a pH equal to or greater than 12.5. Reactive: is reactive with air or water, is explosive, or is cyanide or sulfide. Toxic: has certain levels of certain metals, solvents, or pesticides greater than prescribed limits. Others: any chemical found in the lists in 40 CFR 261 subpart D. b. Classroom Management Make disposal options a part of all laboratory instructions for students. For each chemical waste produced, instruct students as to the appropriate disposal, including disposing of the substance in a disposal container or down the drain.
•See Chapter VII.C.3.c, Drain Disposal.
Place all laboratory waste in a properly labeled container. The label should contain the date and type of waste. Immediately following the laboratory activity, place the waste containers in a secure location until the containers can be removed to the central storage area. Some chemical wastes may be recycled. Teachers should seek guidance on recycling from local safety officers or other knowledgeable administrative staff. c. Drain Disposal
Before considering drain disposal, be certain that the sewer flows to a wastewater treatment plant and not to a stream or other natural water course. Check with the local waste water treatment plant authority to determine what substances are acceptable for drain disposal. Any substance from a laboratory should be flushed with at least 100 times its own volume of tap water. Acids and bases should be at least above pH 3 and below pH 8 before being placed in a sanitary drain.
a. Classification of Hazardous Waste
The Environmental Protection Agency classifies wastes as:
Ignitable: has a flash point below 140°C, is an oxidizer, or is an ignitable compressed gas. Corrosive: has a pH equal to or below 2.0 or a pH equal to or greater than 12.5. Reactive: is reactive with air or water, is explosive, or is cyanide or sulfide. Toxic: has certain levels of certain metals, solvents, or pesticides greater than prescribed limits. Others: any chemical found in the lists in 40 CFR 261 subpart D. b. Classroom Management Make disposal options a part of all laboratory instructions for students. For each chemical waste produced, instruct students as to the appropriate disposal, including disposing of the substance in a disposal container or down the drain.
•See Chapter VII.C.3.c, Drain Disposal.
Place all laboratory waste in a properly labeled container. The label should contain the date and type of waste. Immediately following the laboratory activity, place the waste containers in a secure location until the containers can be removed to the central storage area. Some chemical wastes may be recycled. Teachers should seek guidance on recycling from local safety officers or other knowledgeable administrative staff. c. Drain Disposal
Before considering drain disposal, be certain that the sewer flows to a wastewater treatment plant and not to a stream or other natural water course. Check with the local waste water treatment plant authority to determine what substances are acceptable for drain disposal. Any substance from a laboratory should be flushed with at least 100 times its own volume of tap water. Acids and bases should be at least above pH 3 and below pH 8 before being placed in a sanitary drain.