When working in a lab, waste disposal causes considerable concern. In many cases, legal issues arise from pouring certain chemicals down the drain. Even if legal in your state, chemicals contain hazardous short and long term effects to the environment and human life. The first step in disposing of any water-soluble chemical starts by determining whether the waste meets hazardous criteria.
Consult the material safety data sheets (MSDS) for your water-soluble chemical to determine whether it's toxic, corrosive, flammable or highly reactive. If it meets any of these criteria, it's hazardous. Labs are legally required to keep MSDS for their chemicals on file, so if you do not know where to find the MSDS for a particular chemical, ask your supervisor for help.
Dispose of NON-hazardous water-soluble chemicals by pouring down the drain. Sodium chloride (table salt), for example, is water-soluble and not toxic, corrosive, flammable or highly reactive, which allows for easy disposal down a water drain.
Choose a container to store the waste if hazardous. The container must be chemically compatible with the hazardous waste. Consult the MSDS if in doubt about the types of containers compatible with a given chemical.
Choose an appropriate secondary container. The secondary container must also be chemically compatible with the waste. Use a box or a tub, such as one made of plastic, which contains any spills or leaks from the primary container and prevents them from coming in contact with other materials.
Fill out a hazardous waste tag and attach to the container of hazardous waste. The waste tag lists the owner and hazards of the waste, together with the type of material and the date it was created.
Place your hazardous waste container somewhere safe but reasonably close to the location where you have generated or expect to generate the hazardous waste. If the waste may release toxic fumes, keep the container under a fume hood.
Cap the container. Labs typically contract out with companies that handle hazardous waste and dispose of it in accordance with EPA guidelines, so hazardous waste should be collected periodically.
- UCSD: How to Store and Dispose of Hazardous Chemical Waste
- UCSD Undergraduate Laboratory Safety Exam: Study Guide
- "Chemistry 7L Lab Manual"; Sandrine Berniolles; 2010
- Reed College Laboratory Reference Manual: Disposal
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