David A. Reckhow
Globally, over one billion people do not have access to safe drinking water. The majority of these people live in developing nations, where large-scale drinking water treatment projects may not provide a viable solution because of a lack of skilled laborers, consistent and reliable electricity, materials, sufficient economic capital, and/or fuel sources. Appropriate non-conventional drinking water treatment technologies may provide a solution to these problems, particularly if such technologies are composed of materials readily accessible to the population. Three treatment technologies whose materials are easily acquired throughout the developed and developing world are sari filtration, solar disinfection, and citrus fruit acidification. While some of these technologies have undergone extensive investigation for pathogen removal and inactivation efficiencies, no relationship between the technologies using similar methods and microorganisms has been established. In this research, the removal efficiency and pathogen inactivation of these appropriate technologies was investigated using three indicator organisms: a bacteria (E. coif), a virus (MS2 coliphage), and a surrogate for protozoa (aerobic bacterial spores, B. subtilis). The optimum conditions for pathogen inactivation and removal was investigated by examining a number of variables. As a single treatment method will not provide the safest option for drinking water, a combination of these technologies was also investigated in this research. Ultimately, significant inactivation of E. coli and MS2 coliphage occurred within 4 hours using solar disinfection and 24 hours using citrus fruit acidification. No inactivation occurred for B. subtilis using either of these methods, nor was any significant removal of indicator organisms found when testing sari filtration. Removing the pulp of lemon and lime juice with sari cloth filtration showed no significant removal in MS2 coliphage. However, it was noted that the addition of organic acids to solar disinfection greatly increases the time and inactivation of E. coli and MS2 coliphage. Additionally, the combination of organic acids and solar disinfection can greatly improve MS2 coliphage inactivation on cloudy days. While this research is still in the preliminary stage, the use of appropriate and indigenous treatment options holds a tremendous amount of promise, and should be further studied.