Via ScienceDaily, Dr. James Amburgey, from the University of North Carolina at Charlotte, has developed an inexpensive and low-tech way to treat water using sand. According to Dr. Amburgey, all that is needed to create safe drinking water is PVC pipe, sand and inexpensive treatment chemicals.
Previous technologies have used sand filtration, however, this current prototype cleans water much more effectively and is 30 to 50 times faster. More importantly, it is able to remove Cryptosporidium oocysts, one of the main causes of diarrhea in contaminated water.
In addition to its simplicity and low cost, another advantage of the system is that it can use sands or crushed rock that are found locally.