Geoscience Reference
In-Depth Information
move bacteria for approximately 13,000 gallons, if necessary. This filter utilizes a set of three
silver-impregnated ceramic cartridges with carbon cores.
The AquaRain models use state-of-the-art, award-winning ceramic cartridges from Mara-
thon (a MSR subsidiary) and contain replaceable silver-impregnated activated carbon cart-
ridges for removing chemicals, tastes, and odor. AquaRain model 200 ($199) has a rated capa-
city of 12 to 15 gallons per day and a life of many thousands of gallons. Their model 400
($260) has twice as many filter elements and can process 24 to 30 gallons per day. The com-
plete AquaRain unit has not been through EPA purifier certification; however, the Marathon
ceramic elements used in the AquaRain unit have been thoroughly tested, indicating an excel-
lent microbiological performance.
Note:
Filter life is dependent on water quality, filter surface area, filter thickness, and
ceramic hardness. In actual use, the large-capacity Berkey models and the AquaRain model 400
will probably have about double the useful life of the smaller Berkeys, the AquaRain model
200, and the Katadyn unit.
The recommended high-volume, pump-type unit is the pricey Katadyn Expedition Group
Filter ($1,200), which will pump more than one gallon per minute (much faster than the
gravity-fed units) and has a rated life of 26,000 gallons. Gravity-fed units are considerably less
expensive than pump units with equivalent lifetime capacities. This filter has no carbon core, so
it won't remove bad tastes, odors, or toxic chemicals. It is very popular with river guides and
disaster relief organizations.
Chemical Sterilization
Various forms of chlorine and iodine chemical treatments are commonly used to disinfect
drinking water. Chlorination is the most common method of chemically disinfecting water be-
cause it is easy to apply, readily available, and inexpensive. Chemical treatments, except for
chlorine dioxide (Aquamira, Micropur, and MMS) and the MSR MIOX pen, usually leave an
aftertaste that most people find unpleasant. The taste is caused by traces of chlorine or iodine,
which are active halogens that can also cause harmful health effects over long periods of time.
Caution:
Except for chlorine-dioxide solutions (trade names Aquamira, Micropur, and
MMS), and the MSR MIOX mixed halogens, neither chlorine nor iodine disinfection is effect-
ive against
Cryptosporidium
cysts.
If treated water has a strong chlorine or iodine taste, you can improve the taste by allowing
the water to stand exposed to the air for a few hours, pouring it back and forth several times
