Full Description

The overall objective of this project was to evaluate the efficacy of chemical and photochemical disinfectants in inactivating selected emerging waterborne pathogens. The specific objectives of the project were to: assess microbial inactivation kinetics of selected emerging pathogens;compare the inactivation rates of the selected emerging pathogens to those pathogens that are of considerable concern today (Giardia and Cryptosporidium); determine the impact of selected water quality parameters on inactivation of the selected emerging pathogens; develop and assess selected CT criteria for the emerging pathogens; and, determine whether existing disinfection practices provide adequate treatment for the emerging pathogens. The following emerging pathogens were studied: adenovirus 40; feline calicivirus (as a surrogate for human caliciviruses);mycobacterium fortuitum;legionella pneumophila; and, microsporidia (Encephalitozoon intestinalis). Experiments were conducted using 1,000-mL glass beakers as reactors. The control reactors contained test water and microorganisms, but no disinfectant. The other reactors contained test water, microorganisms and disinfectant (added at t=0). Separate identical reactors were used to collect the disinfectant residual samples and the microbial inactivation samples. The reactors were set up in a recirculating, temperature-controlled water bath. Prior to each experiment the temperature was set at the target temperature for that particular experiment, and was checked using a thermometer with an error of 0.5C. The control samples for bacteria density were taken at the beginning and the end of each experiment. Disinfectant residual and microbial inactivation samples were collected throughout the experiment. The disinfectant residual samples were analyzed immediately. Upon collection, the microbial inactivation samples were mixed with 10 percent sodium thiosulfate solution to remove residual disinfectant. Includes 14 references, tables, figures.

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Edition: Vol. - No. Published: 06/16/2002 Number of Pages: 13File Size: 1 file , 380 KB