With water purification, the two sources I look to for information are always backpackers and those working as aid workers in Third World Countries. Their well being depends upon adequately purifying water.
One product that impresses me (which I recommend in The Prepper Next Door) is the PUR Purifier of Water, which uses iron sulfate as a binder particle to attach to impurities in the water. Then the impurities can be filtered out with a simple coffee filter. The product was developed by Procter & Gamble.
The binder removes all sorts of horrible things including lead, arsenic, DDT, and PCBs.
You almost have to see this stuff in action to believe how well it works. You start off with water that you’d look at and say, “No way in Hell am I ever going to drink that.” Then you mix the stuff in the water and it kinda looks worse. In time, you can filter the water and you end up with water that looks really clear.
There are other commercial products that use this binder concept, which is also called a flocculant. (I like “binder particle” better). Chlor-Floc is one. Instead of using 5 gallon pails, this has tablets for treating one liter at a time.
Here’s a Youtube review of Chlor-Floc by colhane:
The downside to these commercial products, outside of Third World Countries, is expense. I got to thinking that any prepper who got a solid C in high school chemistry can probably figure out what is used as a binder particle and have a go at making their own water-purification flocculants. For do-it-yourself flockers, Alum (aluminum sulfate) seems to be the binder of choice.
Here’s a nice demonstration by CrazyTaileZ (“The Southwest Backpacker”) of using alum to treat murky water.
Here’s a good discussion about an issue that arises, the pH of the water.
One concern is that too much Aluminum might dissolve into the water. In addition, I’d hit the water with a chlorine-based treatment, like the commercial products do. This could easily be done in a second step.
Charlie P., author, The Prepper Next Door: A Practical Guide For Disaster And Emergency Planning