4 Handling Waste

As a student in the chemistry lab, every time you perform an experiment, you will generate waste. Therefore, you have the responsibility to see that the chemicals are identified, handled, and disposed properly. The following information will help you meet this responsibility.

First, you must understand the difference between hazardous and non-hazardous waste:

• Non-hazardous waste: Non-hazardous waste does not cause harm to the environment and may be disposed of in the normal waste stream. Non-hazardous waste includes clean disposable pipets, vials, broken glassware, filter paper, gloves, etc. A small number of chemicals are considered non-hazardous. Where you dispose of these items depends on what it is:

• • Glass disposal (blue broken glassware box): Broken glass and other potentially sharp debris must be placed in the blue broken glass box.
  • Sink: Some inorganic solutions and soap water are non-hazardous and can be flushed down the drain with excess water. These include some, but not all, solutions of sodium, potassium, magnesium, and calcium salts.
  • Trash can: Most of the remaining non-hazardous waste can go in the trash can.

• Hazardous waste: Most inorganic compounds and the vast majority of organic compounds are considered hazardous and should not be flushed down the drain or placed in the trash. These materials must be collected and handled in the hazardous waste stream:

• • Hazardous waste carboys: Each lab has at least one hazardous waste carboy. They are topped with large funnels in which you can pour chemical waste.
  • Contaminated lab debris can: Lab supplies contaminated with hazardous chemicals (e.g., filter paper, paper towels, gloves) can go into contaminated lab debris can.

Note: Sometimes the funnels get clogged or the carboy gets full. In this case, alert your TA and wait to dispose of more waste until the situation is resolved.

In order to comply with government regulations, the contents of hazardous waste containers must be known as accurately as possible. In addition, many wastes are incompatible and should never be mixed together. Mixing of the wastes may cause a dangerous situation (e.g., an explosion or the formation of poisonous gas). Therefore, the hazardous waste containers in the lab are labeled by course number, experiment number, and name/type of waste. If everyone disposes of their waste in the proper container, the container’s contents will be known, and incompatible wastes will not be mixed.

If you are directed to treat the used chemicals you generated to render them non-hazardous, detailed instructions will be given as part of the project. Follow those instructions carefully. With your help, the Department of Chemistry can manage the used chemicals generated in the teaching labs in a safe and environmentally responsible manner.

Note: Unless you are absolutely certain how to dispose of something properly, ask your instructor before you get rid of it!