II. Methods: Boiling
- Water sterilized at onset of boiling
III. Methods: Pasteurization
- Cleans, but does not sterilize water
- Six log reduction in organisms
- Protocols
- Heat at 185 degrees F for 20 seconds
- Heat at 145 degrees F for 30 minutes
IV. Methods: Filtration
- Pore size dependent
- Agent dependent
- Bacteria <.2 micron
- Cryptosporidium < 1 micron
- Virus particles (as small as .0004 micron)
- Avoid sediment
- Clogs filters, harbors organisms
- Technique 1 to clear sediment
- Allow water to sit so sediment can settle
- Pull water off top into filter
- Technique 2 to clear sediment
- Run water through coffee filter first
V. Methods: Halogenation with Chlorine or Iodine
-
Chlorine contact time (assumes standard pH and Temp)
- Escherichia coli: 0.016 ppm Minute
- Enteric virus: 4 ppm Minute
- Giardia lamblia: 150 ppm Minute
- Cryptosporidium: 9600 ppm Minute
-
Tincture of Iodine (5-10 drops added to quart water)
- Indicated for high organic solute load in water
- Not effective against Cryptosporidium
- Avoid in thryoid disease
VI. References
- Wayman (2017) Crit Dec Emerg Med 31(6): 3-10