Disposal of Solid Biological Waste in Research Laboratories
IUPUI Laboratories performing research procedures or activities typically generate biological waste. Often referred to as biohazardous or infectious waste, it may be one of three types. The first is liquid waste, which as the name implies refers to culture media requiring some sort of vessel to contain the volume, aspirate collection in a vacuum Erlenmeyer flask, human or other bodily fluids, or any other material that can be poured. While appropriate to autoclave, the easiest means of decontamination is to add a 10% volume of bleach and allow to sit for 20 minutes. The liquid waste, now treated, can be slowly poured down a lab sink drain followed with copious amounts of tap water. Please note that this only applies to biological waste that is NOT mixed with any form of chemical or radioactive waste, as these should not be poured down a sink drain.
The second type involves sharps originating from laboratory or clinical use. The definition of a sharp is an item that is sharp in its original form (syringe, scalpel, etc.) and can become sharp upon bending or breaking (Pasteur pipettes). These items must be disposed of in a puncture resistant sharps container made of hard plastic. The illustration is NOT a sharps container regardless of how it is labeled. Closed sharps containers are autoclaved and marked as treated, according the Indiana Code and OSHA, prior to disposal.
The third type of biological waste is solid waste intended for autoclaving as a final treatment prior to entering the waste stream. Solid waste (non-sharps) must be collected in a red or orange autoclave bag appropriately parked with a biohazard symbol. These bags should be held in a rigid container or cardboard box commonly known as a “burn up bin”. If the red bag is removed from the container prior to autoclaving it should not contain sharps that can poke through the bag. Usually the bin itself is autoclavable and the bag removed once treated. Good Laboratory Practices notes that all biohazardous waste collection units should be covered at all times – unless of course waste is actively being added to it.
There are concerns at times regarding the need to keep biohazardous waste covered. The rationale is to limit the amount of possible contamination that could be released from the container during waste manipulation or addition. This is especially true for staff present that may not have appropriate barriers in place to prevent exposure. The Biosafety Program based this policy on the NIH Guidelines and the CDC publication the BMBL 5th ed. Another common question is the use of foot pedal activated lids. While convenient it should be mentioned that every time the foot pedal is depressed an upward draft is generated leading to possible release of aerosols and an appropriate risk assessment should be performed to determine whether a foot pedal waste container or simple lid should be used.
Some common mistakes that occur when disposing of biohazardous waste involve over-filling a waste container. There are two issues with the adjacent illustration that should be avoided. First is the obvious over-filling that prevents the contents from remaining in the bag thus resulting in pipettes sticking out of the container. This also prevents the lid from being properly set in place. Improper disposal of biological waste has the potential to expose non-laboratory to biohazardous agents. Staff working for Campus Facilities are instructed to not handle leaking and/or biohazardous waste that has not been treated, i.e., autoclaved. With that said IUPUI research staff are responsible for the approved treatment and disposal of biohazardous waste.
Let’s put some of the above thoughts to work and review the biohazardous disposal processes illustrated below. As you consider 1-4, try to put yourself in the image and what you think you should do. The answers are below the image.
1. Pipettes have been placed in a regular trash receptacle and not a biohazardous bag suitable for autoclaving.
2. Serological pipettes have been tossed into a biohazardous red bag and pointing in various directions from over-filling. These should be disposed of in a pipette box, treated prior to placing in a cardboard box, or placed in a horizontal fashion within a red bag lined cardboard box. This is sealed and placed in a red bag for autoclaving. There is also no lid present to contain possible aerosols.
3. This biohazardous container is extremely overfilled and the contents are at risk of spilling out. The research staff that generated this container would need to repack the contents to alleviate the stress of the cardboard container.
4. This may not be obvious but looking closely at the bottom of the container mold contamination is present. This may indicate a container that is not disposed of in a timely manner.
Thank you for taking the time to read this article and if you should have any concerns or questions please do not hesitate to contact the IUPUI Biosafety Program at firstname.lastname@example.org.