AWWA JAW63325

Water utilities rely on turbidity and particle-count data as a gauge of water quality, but gas bubbles can measure as false particles or turbidity and disrupt the operation of turbidimeters and particle counters. Because bubbles are harmless, it is important for utility managers to know when they are causing spikes in turbidity or particle counts. In this work, the investigators measured bubbles in bench-top laboratory experiments and at a full-scale utility. Although utility managers have long suspected bubbles of interfering with turbidity and particle count measurements, this is the first study that confirms that hypothesis. The results also point out the need for routine quality assurance/quality control (QA/QC) for turbidimeters and particle counters, especially when bubbles are suspected. The study clearly showed that improved QA/QC on particle counters and turbidimeters is necessary in water treatment applications where dissolved gas supersaturation occurs. Includes 31 references, table, figures.