Originally Posted by Bekologist
the FIRST NEED is the only EPA certified PURIFIER available. relying on physical processes alone. but that makes it prone to clogging. All the rest of the water pumps currently available are only 'filters', held to less high of a standard of clean water than a 'purifier.'
The other water pump 'purifiers' relied on chemical- i.e. iodine or proprietary chemical blends - to purify water. The PUR 'purifier' was even recalled because of this.
i'd vote for the First Need for domestic backcountry use, and a field cleanable FILTER system like the MSRs or Kathydin in conjunction with the MIOX pen (or aqua mira- even just bleach) for third world usage. Or a First Need, bringing an extra cartridge for it if the trip is over a month long, and the possibility for a resupply from your support network via post along the way on extremely long duration trips.
There are other EPA approved purifiers on the market such as the AquaStar Plus, while not mechanical it takes only 1 minute to purify water vs 4 hours for the Miox. This system use UV light and there are several other brands that use the same principle and is certified for use in third world countries. There is also a thing called the Steripen Ultraviolet Water Purifier by Pur or Katadyn that is shaped like a pen with a small UV light tube that you submerge in a glass of water and the UV kills all the bad guys, but that one takes a battery to run similar to the AquaStar.
And there are several mechanical units on the market but while they say are portable they weigh 20 pounds and over! Not exactly for backpacking or biking.
Some Katadyn systems requires that you use their Micropur Tablets or Potable Aqua tablets to actually purify the water after you filtered it, seems like a waste of time to me. HOWEVER the Katadyn Exstream is a mechanical water purifier that is very simple to operate and EPA certified:
http://www.nitro-pak.com/product_inf...roducts_id=822
In summary the First Need system is a very good purifier that uses NO chemicals as does the AquaStar Plus; the Katadyn Exstream which can purify up to 26 gallons and is only about $35 vs $100 for the First Need, but the Exstream uses iodine to kill the bad guys.