Development and validation of online surrogate parameters for water quality monitoring at a conventional water treatment plant using a UV absorbance spectrolyser

Absorbance data collected from an online UV absorbance spectrophotometer installed for water quality monitoring at a conventional drinking water treatment plant was used to develop surrogate parameters for treatment process monitoring and optimisation. Surrogate parameters were developed via data analysis of collected online data as well as by targeted selection from previous research knowledge. These parameters were validated in the field using the same online spectrophotometer to gauge their response to events caused by operational changes, such as high chlorine demand and changes in natural organic matter (NOM). Almost all parameters generated responses comparable to the commonly used process assessment UV online parameter, absorbance at 254 nm. Some parameters, such as the derivative of absorbance at 290 nm and the second derivative of absorbance at 310 nm, generated responses far exceeding the standard monitoring parameter, making them potentially useful tools for control of operational treatment processes. It is hoped that in future, these and other novel UV absorbance parameters can be monitored simultaneously to reflect water quality change to further the application of this technology in optimisation of water treatment.