How should we properly dispose of old biological specimens preserved in formaldehyde?
Before starting any disposal procedure, please consult with local government authorities first and review the disposal guidelines in a recent Flinn Scientific Catalog/Reference Manual. Never dispose of any chemicals down the drain if the school is not connected to a sanitary sewer system.
Your specimens are probably packaged in a large bucket or pail. If not, transfer them into a pail. We want to rinse and wash away the preservative from the specimen. The room in which this process is undertaken should be well ventilated.
Place the bucket in a large sink. Attach a length of tubing to the cold water outlet and, wearing gloves, force the exit end of the tubing into the very bottom of the bucket. If possible, use a water outlet equipped with a siphon breaker to eliminate the possibility of backflow.
Turn the water on slowly. You may want to start the water flowing before you force the tubing into the bucket to better gauge and control the water flow. A very slow-but steady-flow is desirable. Allow the water to flow into the bottom of the bucket, forcing the preservative to overflow into the sink. Continue for a period of 8-12 hours.
After the wash cycle is complete, turn off the water, and drain all the remaining water from the container. Place the specimens in the garbage as you would any other organic waste