Idaho Hydro Tech


ISU Study: Humigation Captures Mold and Bacteria

In the fall of 2017, Dr. Peter Sheridan of the Idaho State University Microbiology department began testing the Humigator to learn how well it removes mold spores, bacteria, and viruses from air.  The Idaho Global Entrepreneurial Mission (IGEM) under the Idaho Department of Commerce provide initial funding.

The preliminary findings are summarized below.  Read the entire report here.

Testing Method Summary
A model 1225 Humigator is set up in a dedicated laboratory in the ISU Life Sciences Building. This small Humigator moves approximately 560 CFM. The volume of the lab is about 6,000 cubic feet, so the Humigator cycles the air in the lab about every 11 minutes. Microbes are aerosolized in approximately the middle of the lab, and the Humigator is set up to source air from about eight feet from where it discharges air, also near the middle of the room. There are areas of high air flow and other areas of relatively low air flow in the space because of its shape and the relative locations of the equipment. The lab is cleaned and disinfected before each test.

Each test begins with the Humigator and the microbe aerosolizer turned on simultaneously. A total of 68 collection plates are evenly spaced and placed in a grid on the surfaces of the lab including walls, floor, and ceiling. At the end of each test, the number of microbes on each collection plate is counted, and the number of microbes in the Humigator waste water is also counted. The test plan includes three test configurations with each of three microbe types. Brewer’s yeast (Saccharomyces cerevisiae) is used for the spores. These spores are similar in size to Silver Scurf (Helminthosporium solani) and Black Dot (Colletotrichum coccodes) spores. A benign form of E. coli is used for the bacteria, and a benign virus that infects E. coli (viruses that infect bacteria are called a bacteriophage) is used for the virus test.

Analysis of Preliminary Results
The Humigator captures huge numbers of both yeast spores and bacteria. As noted above, the discharge water microbe counts were similar in recirculating tests and flow-through tests. This was the case for both yeast spores and bacteria. This means that in an atmosphere with high concentrations of microbes, the Humigator collects nearly as many microbes per unit of water as the water can hold.

Peter P. Sheridan
Professor of Microbiology and Biochemistry
Department of Biological Sciences
Idaho State University

Phone: (208) 282-5368



Blake Isaacs