Boiling water every time you want drinking water is really inconvenient for most travelers, so your choices are really using chemicals and filters. Water filters are compact, reliable, and relatively inexpensive when you consider how important they are to giving you safe drinking water. The method that each filter uses may vary, but essentially, they all involve pumping water through the filter at one end while cleaner, filtered water comes out the other. But filtering water does not automatically purify it. This includes some bacteria and protozoa as well.
Purification is a combination of filtering and disinfecting.
It involves actually killing any bacteria, protozoa and viruses in the water. Disinfecting water is accomplished by using chemicals or boiling water. Water filters are very simple to use, but employ a very intricate design. As the water passes through the filter, small particles are trapped within the interior surface of the filter. The surfaces are made of ceramic, glass fiber or other porous material which needs to be cleaned periodically, depending on the amount of use.