Germicidal Radiation Technology in Water Membranes

Skyler McLean
January 27, 2018

Submitted as coursework for PH241, Stanford University, Winter 2017


Fig. 1: A 1000 liter reverse osmosis plant for commercial use. (Source: Wikimedia Commons)

In water treatment, one of the most common ways to filter the water is by forcing it through a membrane. This process is used in many applications from the production of drinking water through reverse osmosis (Fig. 1) to wastewater treatment and even filtering water for the food industry. While this is an effective way to filter water, sometimes biofouling happens, which is when the membrane gets contaminated with a layer of bacterial biofilm. Not only is this bacteria potentially dangerous, it clogs the membrane and decreases the water flow. [1] With a decreased water flow comes increased operational costs for the water filtration plant. Membranes often need to to be removed in order to undergo disinfection, but this costs time and is an even easier opportunity for bacteria to traverse the membrane. Chemical treatment is effective at killing bacteria, however strong chemicals damage the membrane. [1]

Proposed Solution

Johnson et al. have suggested a new method for treating biofouling through radioluminescence membrane biofouling control. Radiation is a highly effective way to kill bacteria. Unfortunately at the moment there is no way currently to expose the inside of the water filtration tubes to UV radiation. [1] In radioluminescence enabled water filtration plant, a radioluminescent phosphor would be coated within the filtration tubes, and this coating would be excited by X-Ray delivered from outside the tubing. Using this technology, bacteria would be killed without chemicals and the filter would remain in operation during cleaning. [1]

Other Applications

While the above paper focuses primarily on water treatment solutions, irradiation techniques can be applied to other aspects of food production. By exposing food to a controlled amount of radiation, DNA in the bacteria on the food is broken down and reproduction is halted. [2] This process can help lengthen the shelf life of foods and kill dangerous bacteria that might otherwise be consumed, although further steps may be needed for full sterilization. [3]

© Skyler McLean. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] T. A. Johnson et al., "Bacteria Inactivation via X-ray-Induced UVC Radioluminescence: Toward in Situ Biofouling Prevention in Membrane Modules," Environ. Sci. Technol. 50, 11912 (2016).

[2] D. Poplawski, "The Use of Nuclear Technology in Agriculture," Physics 241, Stanford University, Winter 2015.

[3] C. Kao, "Nuclear Technology for Food - Food Irradiation," Physics 241, Stanford University, Winter 2012.