AWWA JAW56688

Despite years of research, the mechanisms by which microorganisms survive in distribution systems and how various water quality parameters affect their survival are still not fully understood. Several factors affect bacterial regrowth in drinking water supplies. Although biodegradable organic materials, the "food" for bacteria, have often been thought to be a main culprit, this study shows that may not be the case. By evaluating the biological quality in a full-scale chloraminated distribution system, this study examined the various factors that affect bacterial regrowth. The conclusions of this study are likely to help utility managers gain a better understanding of the factors controlling bacterial regrowth and help them make well-informed decisions on treatment process improvement or distribution system maintenance. For example, rather than merely reducing the concentration of biodegradable organic matter, utilities may need to take multiple approaches to maintain good biological quality or to solve existing problems in their distribution systems. Includes 34 references, tables, figures.