Important application of turbidity measurement. Many water supply systems depend partly on natural spring water. Frequently a spring will become unusable at certain times (snowbreak, thunder storms, etc.), which makes it necessary to monitor its turbidity continuously. Because the instruments, often in remote locations, switch automatically between "use" and "discard", they have to work reliably with virtually no maintenance. The Sigrist configuration with the stable alternating beam method and the windowless flow cell is ideal for this application.
In many areas there is a danger of spring water contamination from leaks in fuel oil tanks. In these cases, oil trace measurement by the fluorescence principle is used instead of turbidity measurement.