APPLICATION – LuminUltra – Drinking Water


LuminUltra – Drinking Water

Mapping and Identifying the Source of Water Quality Issues

A Southern U.S. municipality experiencing taste and odour issues in a certain neighbourhood was also having difficulty maintaining chlorine residual levels in the area. Biological growth was suspected, however, water leaving the treatment plant met and exceeded all water quality requirements. After several investigations, the source of contamination in the distribution system could still not be identified.

Test Plan

The utility was successfully using 2nd Generation ATP testing in their water treatment plant to monitor biological fouling in the membrane filtration unit. Since they were already equipped to perform water analyses using LuminUltra’s QGA test kit, it was decided that the kit would be taken into the field to audit the distribution system and determine whether the cause of the taste and odor complaints was biological contamination.

Testing began at the water treatment plant where it was confirmed that biological content was very low (<1pg ATP/mL) and therefore well within the acceptable range. Operators then travelled to the affected neighbourhood and began to audit the system, tracing back to the water treatment plant.


The results confirmed that biological growth was significantly higher in the affected neighbourhood with ATP levels in the high-risk range of >10pg ATP/mL. The line was traced back toward the treatment plant and water samples were tested at several major junction nodes. ATP results remained high near the neighbourhood until suddenly, between sample point B and A, there was a significant drop in ATP levels back into the good control range of <1pg ATP/mL.

Upon further investigation, operators discovered a leaking valve that was not identified on the design drawings. Significant biofilm growth had built up on the valve and was entering the distribution system causing the disinfectant residual loss and water quality issues for consumers. Operators repaired the valve immediately and flushed the lines. Residual chlorine levels were quickly restored and follow-up ATP testing confirmed that biological growth in the system had dropped back into the good control range.


Having a field-ready rapid microbiological test allowed water distribution system operators to quickly audit their system and pinpoint the source of water quality issues. Routine distribution system monitoring was implemented to proactively monitor for biological regrowth and prevent similar water quality issues from affecting consumers in the future.

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