Vacuum line trap systems are utilized across campus research laboratories to collect liquid biohazardous waste and prevent suction of infectious and non-infectious materials into vacuum lines (house vacuum line or vacuum pump). Setting up your vacuum line trap system correctly will allow for safe collection and decontamination of liquid biohazardous waste.
Source: CDC, Biosafety in Microbiological and Biomedical Laboratories (BMBL), 6th Edition
The diagram above details the correct setup of two vacuum flasks and an in-line hydrophobic/HEPA filter in series connected by vacuum lines to a port for house vacuum. Alternatively, a vacuum pump may be used if house vacuum is not available.
Liquid waste material is drawn into the catch flask A which is pre-filled with an appropriate disinfectant*. Flask A is connected to the overflow flask B. Note that flask B is empty. Flask B provides overflow protection for flask A. Care must be taken to prevent overflow of flask A. An in-line hydrophobic/HEPA filter C is located between overflow flask B and the vacuum port D. Both flasks should be seated in a spill tray to contain any spill should the flasks be knocked over. The spill tray must be non-porous and autoclavable.
*Household bleach is commonly used for disinfection of liquid biohazardous waste. When utilizing household bleach for disinfection of liquid biohazardous waste, the catch flask A should be pre-filled with household bleach such that when the flask is 2/3 full, the final concentration is 10% bleach. Ensure appropriate contact time (20 minutes for 10% bleach). Once the appropriate concentration and contact time have been met, test the pH of the liquid using a pH meter or pH test strip (available upon request from Research Safety) to ensure it is within acceptable limits for drain disposal (5.5-11.5 SU). Once the mixture has met all requirements (10% bleach, 20 minutes, pH 5.5-11.5), it may be poured carefully and slowly down the laboratory sink drain with copious amounts of water.
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Flasks should be constructed with heavy walls to withstand vacuum pressure. Note that appropriate flasks have a glass hose connector such that flasks may be connected in series.
Vacuum tubing should be thick-walled such that it can withstand vacuum pressure without collapsing and be autoclavable.
(One hole) Size 8 will fit 1L flasks. Size 9 will fit 2L flasks.
Spill tray must be non-porous, autoclavable, and of a size appropriate to contain the contents of flasks in case of spill.
In-line vacuum line filters must be hydrophobic/HEPA filters.
pH test strips must display the full pH range (0-14).
NOTE – UK Research Safety will provide pH test strips to researchers free of charge! Simply email biosafety@uky.edu to request pH strips for liquid biohazardous waste.