UV-254 measurements are a practical indicator of dissolved organic compounds in water. Traditional methods such as TOC, COD, and BOD all capture more organics and other potential contaminants but have the drawback of being expensive and maintenance intensive. In fact, most are done only in the laboratory due to the complexity of on-line systems.
UV-254 measurement is much simpler and can be correlated to DOC levels. It has the advantage of being nearly real time, providing input to treatment control systems and alarming of abnormal conditions. Routine maintenance consists of cleaning the optical surfaces, which is generally simple and quick.
The Q46UV UV254 monitor provides additional optical measurements for added measurement capabilities and increased reliability. Infrared sensors for measuring both 90° Scatter Turbidity and IR absorption are built into the UVA sensor. These additional optics allow for the measurement of both UV-254 and Turbidity, a unique capability to enhances the usefulness of the monitoring package, especially in raw water monitoring applications. The IR absorption measurement is used to correct measurements for minor optical fouling that can occur over weeks or months of operation.
Sensors in contact with raw or settled water samples may experience fouling from iron and manganese. Pre-chlorination causes iron and manganese to precipitate out of solution and coat surfaces that are in contact with the sample. While manual sensor cleaning is easy, ATI offers Q-Clean, an automatic sensor cleaning system that reduces user maintenance.
The cleaning system consists of an automatic sensor wash system that injects a cleaning solution into the sensor flow chamber at the frequency programmed by the operator. The cleaning solution contains chemicals that dissolve iron and manganese that has accumulated on optical surfaces.