Online water quality monitoring and process control using UV-Vis sensors

First published in Water e-Journal Vol 7 No 1 2022.

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Research Questions

• Why and how suspended particles in the water affect water quality measurements using online UV-Vis instruments?
• How to eliminate particle interference and obtain accurate measurements of UV254 using online UV-Vis instruments?
• Can we use UV-Vis spectra directly or indirectly for water treatment process control?
  

Objectives

• Provide in-depth knowledge of the impact of suspended particles on online UV-Vis measurements.
• Develop software compensation techniques to improve online measurement.
• Develop models using spectra information to predict chemical dosing for water treatment process control.

Findings to date

• New knowledge added in understanding the effect of particle type and concentration on UV-Vis measurements and the compensation techniques.
• A universal compensation algorithm has been developed with better accuracy compared with the generic algorithm which has suffered from undercompensated or overcompensated measurements in some cases.
• Confirmed the use of single wavelength compensation with similar accuracy compared with the multiple wavelength compensation for online instruments as built-in compensation algorithms.

Industry:

• Simple UV–Vis instruments with a single wavelength could be employed in the field to monitor water quality.
• Chemometric models based on UV-Vis spectra can be developed into decision support tools for water treatment process control.