AWWA JAW10124

The objective of this study was to ascertain any relationships among acid-fast organisms and conventional microbial parameters and to determine removal efficiencies through conventional treatment processes. Sampling was conducted at eight locations at a water utility in Concord, New Hampshire, as well as a utility in Manchester, New Hampshire. The parameters analyzed included acid-fast organisms, total coliforms, standard plate count (SPC), membrane standard plate count (m-SPC), free and total chlorine residual, total organic carbon (TOC), pH, turbidity, and temperature. These data were analyzed by using computerized statistical packages. Results showed that densities of acid-fast organisms in raw water correlated with concentrations of total coliforms and the level of turbidity. Sand filtration removed acid-fast organisms, and the densities of acid-fast organisms decreased with increasing distance from the treatment plant. Conventional terminal chlorination appeared to have no statistically significant effect on the density of the organisms leaving the plant. Overall, chlorine residuals had a negative effect on densities of acid-fast organisms, whereas turbidity and TOC had positive effects on microbial concentrations. Includes 15 references, tables.