AWWA WQTC62502

Listed on the US Environmental Protection Agency Contaminant Candidate List 2, Mycobacterium avium is anopportunistic human pathogen found in municipal drinking water systems. Its survivaland presence in drinking water has been attributed to its resistance to chemicaldisinfection by single applications of chlorine, chloramines, ozone, and chlorine dioxide.However, current disinfection strategies exist that employ the use of a primary andsecondary disinfectant. Inactivation kinetics of M. avium with monochloramine hasdemonstrated the presence of an adaptive response triggered by pre-exposure torelatively low concentrations of monochloramine (<1 mg/L). Subsequent inactivation bymonochloramine at higher concentrations (>5 mg/L) proceeds at a slower rate comparedto that without the pre-exposure. With some utilities using both freechlorine and monochloramine, the objective of this study was to elucidate any synergisticand/or adaptive responses exhibited by M. avium to sequential treatment. In addition,while free chlorine inactivation kinetics has been reported in the literature, a comprehensivestudy on the effects of water quality parameters is still needed. Despite the fact that M.avium is often found within biofilms, this study focused on the inactivation kinetics of M.avium as suspended cells in order to provide the baseline kinetics for future work withbiofilms. The experimental results presented here are for single-step free chlorine andsequential free chlorine/monochloramine as a function of pH, temperature, anddisinfectant concentration. Includes 5 references, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

6

File Size:

1 file , 140 KB