An optical dissolved-oxygen sensor and analyzer for use in wastewater aeration basins and ponds more easily resists fouling than do polarographic sensors, says its manufacturer.

Introduced by Emerson Process Management, Irvine, Calif., Rosemount analytical RDO device comes with either an integral or quick-disconnect cable. A 1.25" FPT fitting at the sensor’s rear allows a threaded pipe to be screwed into the unit so it can be submerged in the basin. Because it does not require a flowing sample, the sensor works well in a low-flow basin or pond.

Maintenance primarily consists of replacing the sensing cap once a year. The analyzer accepts one or two sensors. It has a two-line display, which can be customized to show mg/L (ppm) oxygen, percent saturation, oxygen partial pressure or temperature for either sensor.