UV254 absorbance as real-time monitoring and control parameter for micropollutant removal in advanced wastewater treatment with powdered activated carbon

This study investigates the applicability of UV absorbance measurements at 254 nm (UVA(254)) to serve as a simple and reliable surrogate parameter to monitor and control the removal of organic micropollutants (OMPs) in advanced wastewater treatment applying powdered activated carbon (PAC). Correlations between OMP removal and corresponding UVA(254) reduction were determined in lab-scale adsorption batch tests and successfully applied to a pilot-scale PAC treatment stage to predict OMP removals in aggregate samples with good accuracy. Real-time UVA(254) measurements were utilized to evaluate adapted PAC dosing strategies and proved to be effective for online monitoring of OMP removal. Furthermore, active PAC dosing control according to differential UVA(254) measurements was implemented and tested. While precise removal predictions based on real-time measurements were not accurate for all OMPs, UVA(254)-controlled dynamic PAC dosing was capable of achieving stable OMP removals. UVA(254) can serve as an effective surrogate parameter for OMP removal in technical PAC applications. Even though the applicability as control parameter to adjust PAC dosing to water quality changes might be limited to applications with fast response between PAC adjustment and adsorptive removal (e.g. direct filtration), UVA(254) measurements can also be used to monitor the adsorption efficiency in more complex PAC applications. (C) 2016 Elsevier Ltd. All rights reserved.