Purifying water through the sands of time

摘要

Water is vital for life, but unless it is clean, it contains many hidden dangers. The World Health Organization (WHO) reports that there are more than 1,415 species of infectious organisms known to be pathogenic to humans. It states: "Many of these organisms are associated with diseases that have been known for many years, a small but significant percentage are associated with more recently emerged diseases, such as Acquired Immunodeficiency Syndrome (AIDS), Ebola and Severe Acute Respiratory Syndrome (SARS)."