I always understood the we need one gallon per day per person sothat makes the 185 gallons it can do less than a year.

although one gallon per person is truly an over-simplification of a human's water requirement, it likely refers to all water intake and not specifically water drank on its own, in liquid form.

There is a flocculation packet made by Pur for humanitarian relief that would seem more practical for large scale but not as inexpensive from what the info below states.
Recently it was written up as a new product:
The PUR Purifier of Water treatment could be a solution.

Each 4 g (0.14 oz) packet treats 2.5 gallons/10 liters and takes 30 minutes. ($185 for 185 gallons?)

Step 1. Mix: You add the packet (0.542% calcium hypochlorite, 99.458 % other ingredients) to 10 liters of water.

Step 2. Stir: Stir well for 5 minutes. Let stand for 5 minutes. If water is not clear stir again until the floc is separated.

Step 3. Filter: Use clean thick 100% thick cotton cloth without any holes to filter. Dispose of filtered floc away from children and animals. Wait 20 minutes.

Step 4. Drink It'll be sold two ways:

1. as six (4 g) PUR packets and a cotton filter cloth ($14.99)

2. as a kit with mixing container, storage container, stirring wand, cotton filter cloth, packet opener, and three Pur packet ($28.99).

This link has the humanitarian info:
http://www.pg.com/company/our_commitment/drinking_water.jhtml;jsessionid=SZSW5FN1KV5OHQFIAJ1XKYWAVABHM3MK

This product has seriously limitations that place big doubts upon its practicality and usefulness.

It uses high-tech ion-exchange resin, which, although I cannot find pricing info on the website, suggests it is expensive. A new unit must be purchased at least once per year and I wonder how many people could afford it. (The unit is designed to provide 2 L of drinking water per day; US EPA recommends 2.5 L/day.)

It only treats water for one person, and cannot be expanded to meet the needs of a household or small community. Each person has to have their own unit and so cannot take advantages of an economy of scale.

It cannot deal with turbid water and will quickly become clogged, which will probably ruin the unit and necessitate the purchase of additional units.

It does not remove arsenic or any other heavy metals.

It does not remove giardia or cryptosporidium or other parasites -- these are major issues, and the fact that the LifeStraw cannot deal with them makes it worthless in my opinion. These are the main killers of infants through enteric disease.

It's meant to be carried everywhere, worn on a string around the neck, etc. which presents difficulties in terms of the technology being taken up, adapted and used within the culture of the recipients. I'm doubtful of this technology being easily taken up and used. (It looks dorky to use...this sounds like a joke but it is a serious cultural barrier to technology uptake.)

And the whole thing depends upon people being able to purchase units from a distributor. Thus folks are dependent upon having enough money, and having a local distributor from whom to purchase the units they need.

A much better solution would use inexpensive or free and locally-abundant materials to purify drinking water, and would necessitate a minimum of disturbance or modification of present culture and practices.

At AqueousSolutions, we are providing such solutions and empowering communities around the world to attain self-reliance in drinking water purification. This way they are not increasingly dependent upon buying high-tech devices from Western for-profit corporations.

You can read about our research and projects in the field at www.aqsolutions.org.

The LifeStraw seems like it was developed by a bunch of Western engineers who may have never even been to a developing country, and marketed by entrepreneurs who may not understand or care about the issues involved with technology uptake that make or break the authentic success of such an innovation. It seems to be designed more to be profitable than practical.

www.aqsolutions.org.