ABSTRACT
Microbial response is a measure of the sensitivity of the microorganism to UV light and is unique to each microorganism. UV doseresponse is determined by irradiating water samples containing the microorganism with various UV doses and measuring the concentration of infectious microorganisms before and after exposure. The microbial response is calculated using the following equation:
Log inactivation = log10 N/N0
where N0 = concentration of infectious microorganisms before exposure to UV light, N = concentration of infectious microorganisms after exposure to UV light, and
Log inactivation of streptococci = log10 546/2987
= –0.738
10. If water having an E. coli load of 3290 CFU/ml was treated with UV irradiation and the concentration of the microbes reduced to 1200 CFU/ml, comment on the microbial response. A similar experiment was conducted using water with coliform density of 4362/100 ml, and after UV treatment the coliforms were inactivated reducing their concentration to 200/100 ml. Comment on the coliform response to UV irradiation and also mention which microorganism is susceptible to UV treatment.
