The issues of clean drinking water can be tackled in many appropriate ways. We will not cover all of them here, but we will cover some that we have used to help people. First lets point out that the issue we are discussing here is not access to water, but rather making the available water palatable (safe to drink).
Bio Sand Filtration:
These filter have been installed in many remote locations with a high rate of success. The simple science explanation for how it works is simply that as the water moved through the top layer of sand, the microorganisms like that environment and stick themselves to the top layer of sand in the filter. The water that is pushed all they way through and comes out the spout is about 98% pathogen free.
To see a good description of how this Bio Sand filter works see SON International.
Moringa seed settling:
The dried seeds from a Moringa tree can also make water clean. Turbidity (undissolved partials in water) always have a negative molecular charge. However the seeds kernels of Moringa have a positive molecular charge. Crushing the seeds into powder and putting them in water will cause the turbidity to settle to the bottom. Additionally however, the Moringa seed has a natural microbial agent which also kills pathogens in the water. There are lots of articles these days on the web about Moringa water treatment. However, if you want to read some scholarly articles I would recommend the following. Article #1. Article #2. If you want to read further on this subject search for works done by “Department of Microbiology, Obafemi Awolowo University, Nigeria”
Solar water disinfection:
Another very simple but effective way to purify water is by solar water disinfection. Put the water in a clear bottle and place in the sun for some hours. However, the water must be clean already. Microorganism that can make you sick are smaller then dust particles. So if you water has any turbidity in it, this method does not work well. as the germs can hide in the shadow for the dust. For more on this method, check out this article.