AWWA JAW64356

As surrogates for viruses, bacteria, and protozoa, fluorescent microspheres can be used to challenge pathogen-removal technologies and determine their efficacy in removing contaminants of interest. In addition, microspheres are helpful in quantifying flow patterns and mixing characteristics. However, the most common microsphere enumeration method, direct count by fluorescence microscopy, requires skilled operators and expensive equipment. In the research discussed here, a prototype device that used laser scanning cytometry and that was constructed of relatively inexpensive components performed at least as well as the microscope for the range of ~5-200 µS/mm². Among the many challenges facing water providers today are increasingly stringent regulations and the threat of intentional contamination of water sources with pathogens. A device such as the prototype described here would offer utility managers a way to test their water supply technologies with more accuracy and precision. It represents a building block toward more advanced (but still low-cost) technologies that can detect pathogens and help reduce risks. Includes 7 references, figures.