SOLAR WATER DISINFECTION AND POSSIBLE APPLICATION FOR HOUSEHOLD PURPOSES

Sunlight possesses a potential germicidal activity, which varies throughout the day and the year, as well as with geographical locations and climatological status. In order to explore this phenomenon an attempt was made to investigate the possibility of using sunlight for water disinfection in the hope to apply this technique in areas where conventional water disinfection processes are not available. Autoclave sterilized raw river water containing a known concentration of E.coli cells was exposed to sunlight, for varying time intervals, in 50, 100, 500 and 1000ml glass bottles. Cells mounted on membrane filters were also exposed to sunlight in the same manner in order to study the direct effect of sunlight on bacterial cells. Results showed that about 4 hours of continuous sunlight exposure were required to reduce survivors to about 0.01% (4 log cycles) in bottles. The volume of exposed samples did not have significant influence on the efficiency of inactivation. However, about one hour was needed to achieve the same level of survivors with cells mounted on filters. Generally, solar inactivation capacity increased with the progression of the day giving a peak efficiency at 12:00-16:00 in winter, 11:00-17:00 in spring and autumn, and 10:00-18:00 in summer.

[1]  R. Fujioka,et al.  Effect of sunlight on survival of indicator bacteria in seawater , 1981, Applied and environmental microbiology.

[2]  Janet L. Hopson,et al.  Essentials of biology , 1990 .

[3]  Kevin G McGuigan,et al.  Solar disinfection of drinking water and diarrhoea in Maasai children: a controlled field trial , 1996, The Lancet.

[4]  R. Fujioka,et al.  Effect of sunlight on enumeration of indicator bacteria under field conditions , 1982, Applied and environmental microbiology.

[5]  F. L. Gates A STUDY OF THE BACTERICIDAL ACTION OF ULTRA VIOLET LIGHT , 1929, The Journal of general physiology.

[6]  M. Ellison,et al.  PYRIMIDINE DIMERS INDUCED IN ESCHERICHIA COLI DNA BY ULTRAVIOLET RADIATION PRESENT IN SUNLIGHT , 1981, Photochemistry and photobiology.

[7]  T. McMeekin,et al.  Effect of solar radiation and predacious microorganisms on survival of fecal and other bacteria , 1981, Applied and environmental microbiology.

[8]  D. Ciochetti,et al.  Pasteurization of naturally contaminated water with solar energy , 1984, Applied and environmental microbiology.

[9]  R. Reed,et al.  Solar inactivation of faecal bacteria in water : the critical role of oxygen , 1997, Letters in applied microbiology.

[10]  B. Juven,et al.  Destruction of coliforms in water and sewage water by dye-sensitized photooxidation , 1977, Applied and environmental microbiology.

[11]  Kunte,et al.  Inactivation of Salmonella typhi by high levels of volatile fatty acids during anaerobic digestion , 1998, Journal of applied microbiology.

[12]  W. Harm Biological effects of ultraviolet radiation , 1980 .

[13]  A. W. Downing,et al.  III. Researches on the effect of light upon Bacteria and other organisms , 1878, Proceedings of the Royal Society of London.

[14]  D. Alexander,et al.  Characterization of mutations induced by 300 and 320 nm UV radiation in a rat fibroblast cell line. , 1996, Mutation research.

[15]  Andrew G. Glen,et al.  APPL , 2001 .

[16]  B. Harris,et al.  Arab League Educational, Cultural and Scientific Organization (ALECSO) , 1986 .

[17]  R. Mitchell,et al.  Solar radiation induces sublethal injury in Escherichia coli in seawater , 1981, Applied and environmental microbiology.

[18]  R. F. Hill ULTRAVIOLET‐INDUCED LETHALITY AND REVERSION TO PROTOTROPHY IN ESCHERICHIA COLI STRAINS WITH NORMAL AND REDUCED DARK REPAIR ABILITY , 1965, Photochemistry and photobiology.

[19]  P. Hartman,et al.  Breakthrough of ultraviolet light from various brands of fluorescent lamps: Lethal effects on DNA repair‐defective bacteria , 1996, Environmental and molecular mutagenesis.

[20]  J. Berciano,et al.  Botulism and pregnancy , 1996, The Lancet.

[21]  R M Conroy,et al.  Inactivation of fecal bacteria in drinking water by solar heating , 1996, Applied and environmental microbiology.

[22]  John E. Frederick,et al.  SOLAR ULTRAVIOLET RADIATION AT THE EARTH'S SURFACE , 1989 .