EXPERIMENTAL EVALUATION OF A NOVEL PHOTODYNAMIC WATER DISINFECTION TECHNIQUE

This bench-scale study explores and evaluates the feasibility and effi cacy of the combination of two previously reported techniques for the photodisinfection of heavily polluted water. These are: (a) photodynam ic disinfection of excessively polluted water with methylene blue as a sensitising dye and exposure to solar UV-A radiation; and (b) the 'Ha losol Process', designed to achieve an effective bactericidal action b y solar irradiation of super-chlorinated water. The objective of the p hotodynamic disinfection technique is to broaden the biocidal spectrum , and to achieve a combination of germicidal effects, decolourisation, and dechlorination. It is applicable in the developing countries, whe re sunlight abounds and enteric diseases are prevalent. The halosol pr ocess may be applied in these countries to water from relatively clean sources.