08 Water Purification: Physical Treatment: Microfilters: Products
Description
This article is from the Water Treatment FAQ, by Patton Turner with numerous contributions by others.
08 Water Purification: Physical Treatment: Microfilters: Products
Basic Designs Ceramic Filter Pump ($29/$15, 8 oz.) Cheap flimsy
filter, claimed to filter up to 500 gallons with a .9 um ceramic
filter. Not EPA rated, may not have passed independent lab tests,
prone to damage, filter element must be submerged in water.
General Ecology- First Need Deluxe ($70/$30, 20 oz) This filter uses a
structured matrix micro strainer, though General Ecology won't reveal
what the structure is. It has survived independent lab tests, and
filters particles to 4 um, while actually removing viruses (the only
filter capable of doing this) through electrostatic attraction. The
filter cartridges can't be cleaned (other than by backflushing), but
are good for 100 gallons. Pump design isn't the best. Other models
are available from the manufacturer.
Katadyn PF ($250/$145,22.7 oz). The original microfilter using a .2
um silver impregnated ceramic candle. An extremely thick filter
allows it to be cleaned many times for up to 14,000 gallons capacity.
While the Katadyn seems well made, one reader of this list reported
breaking the candle, and Backpacker Magazine broke the case during a
field test. The pump, while probably indestructible, is somewhat slow
and hard to use, requiring 20 lbs. of force on a small handle. The PF
also lacks a output hose as
the Katadyn engineers felt if would be a source of contamination.
Katadyn Combi ($185/$75 (ceramic)/$19 (carbon), 29 oz) A cheaper
version of the PF incorporating both ceramic and carbon stages. Much
faster filter than the PF. Katadyn Minifilter ($139/$59, 8.3 oz) A
smaller and cheaper version of the PF, easier to pump, but generally
not well received. Good for 200 gallons.
Katadyn Expedition ($680,$77 13 lb.) Similar filter to the PF (exact
same cartridge as the Drip Filter Below) but designed for much higher
production, stainless steel case with spade type D handle, produces
.75 gpm. Filter good for 26000 gallons.
Katadyn Drip Style Filter ($240, $77 12.5 lb.) Filter elements
similar to those in the PF are mounted vertically in top 3 gallon
plastic bucket, water drips through filters into second 3 gallon
bucket with faucet. 1 qt, per hour with the 2 filters included, a
third filter can be added to increase rate 50%. Some units are being
shipped with 3 filter. Each filter is good for 13000 gallons. The
mounting hardware for the filters is available for $10 to allow you to
make your own filter of what ever size is needed. Each mounting kit
requires a 1/2" hole in the bottom of the raw water container.
Katadyn Siphon Filter ($92, 2 lb.) Similar design to PF filter
element, but a siphon hose replaces the pump, filters 1-2 quarts per
hour (allow 1 hour for the filter to "prime" itself via capillary
action), but multiple filters can be used in the same container.
Collection vessel must be lower than raw water container. Good for
13000 gallons
MSR Miniworks ($59/$30, 14 oz) MSR's smaller filter, using a .3 um
ceramic element. Pump is well designed, and easy to use. Main
drawback is that the clean water discharge is from the bottom of the
filter, and no hose is provided. While the bottom is threaded for a
Nalagene bottle, it is a pain in the butt to fill a canteen or 2
litter bottle. Claimed to filter 100 gallons, Backpacker Magazine
feels this may be one of the few filters without a grossly inflated
rating
MSR Waterworks ($140/$30/$30, 17 oz) MSR's first filter with a .2
micron ceramic, membrane stage and a carbon stage. Other wise similar
to the Miniworks.
PUR Pioneer ($30/$4, 8 oz), newly introduced low end microfilter. .5
um, 1 lpm filter rate, 12 gallon capacity
PUR Hiker ($50/$20, 12 oz) PUR's microfilter only design, filters to
.5 um, 200 gallon capacity. Well liked, as are the other PUR filters.
Very compact. 200 gallon capacity
PUR Scout ($70/$35/$15, 12 oz) Combines a iodine resin stage , a 1.0
um filter, and a activated charcoal filter. 200 gallon capacity
PUR Explorer ($130/$45, 22 oz) PUR's top of the line model. bulky,
but well made, with a high output (1.4 lpm, faster than any of the
hand held models listed and one of the easiest to pump) Has a 1.0 um
filter plus a iodine resin stage, 300 gallon capacity
Sweetwater Walkabout($35/$13, 8.5 oz.) Sweetwater's low end filter,
0.2 um, .7 lpm, 100 gal capacity
Sweetwater Guardian ($60/$20, 11 oz) Uses a glass fiber and carbon
filter, filters to ..2 um, claimed to last for 200 gallons. A iodine
resin stage can be added that will kill viruses, and will last for 90
gallons. Pump is well designed, but it takes a few seconds to
pull a captive pin to fold for storage. Available in white or OD.
Timberline Eagle ($20/$13, 8 oz) At 1 um, this filter only does
protozoa, but is much easier to pump. lighter, and cheaper. Filter is
attached to pump, and must rest (but doesn't have to be submerged) in
water to be purified. Looks flimsy, but seems to hold
up. Claimed to last for 100 gallons.
It is also possible to build your own microfilter using diatomaceous
earth, sold for swimming pool filters (DE). Usually pressure is
required to achieve a reasonable flow rate. A DE filter will remove
turbidity as well as pathogens larger than 1 um.
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