Spectroscopic Methods for Online Water
Quality Monitoring
Joep van den Broeke and Ton Koster
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
2 Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
3 Interaction of Light and Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
4 Signal Treatment . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 289
4.1 Data Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
4.2 Transformations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
4.3 Chemometrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
5 In Situ Spectroscopy for Water and Wastewater Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
5.1 UV/Vis Absorption Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
5.2 Fluorescence Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
5.3 NIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
5.4 Further Optical Technologies with Potential for Online Use in Smart Water Systems 304
6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
7 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
Abstract Sensors deployed in smart water systems need to meet a number of criteria,
first and foremost robustness of performance, autonomous operation and low maintenance. Solid-state, optical sensors are at the forefront in the development of the next
generation of sensors for smart water systems. A range of optical sensor technologies
is currently in use for (near) real-time water quality analysis and between them can
cover most of the relevant quality parameters. Technologies used in the water
industry include UV/Vis absorbance, fluorescence and NIR absorbance spectroscopy. Spectroscopic methods with potential for broader application include Raman
spectroscopy and laser-induced breakdown spectroscopy. All approaches share the
following properties: fully solid-state hardware, no reagents or other consumables
required for their operation, and automatic interpretation of the sensor data performed
J. van den Broeke (*)
KWR Water Research Institute, Nieuwegein, The Netherlands
e-mail: joep.van.den.broeke@kwrwater.nl
T. Koster
Enschede, The Netherlands
Andrea Scozzari, Steve Mounce, Dawei Han, Francesco Soldovieri,
and Dimitri Solomatine (eds.), ICT for Smart Water Systems: Measurements and
Data Science, Hdb Env Chem (2021) 102: 283–314, https://doi.org/10.1007/698_2019_391,
© Springer Nature Switzerland AG 2019, Published online: 31 August 2019
283
Quality Monitoring
Joep van den Broeke and Ton Koster
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
2 Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
3 Interaction of Light and Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
4 Signal Treatment . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 289
4.1 Data Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
4.2 Transformations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
4.3 Chemometrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
5 In Situ Spectroscopy for Water and Wastewater Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
5.1 UV/Vis Absorption Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
5.2 Fluorescence Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
5.3 NIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
5.4 Further Optical Technologies with Potential for Online Use in Smart Water Systems 304
6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
7 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
Abstract Sensors deployed in smart water systems need to meet a number of criteria,
first and foremost robustness of performance, autonomous operation and low maintenance. Solid-state, optical sensors are at the forefront in the development of the next
generation of sensors for smart water systems. A range of optical sensor technologies
is currently in use for (near) real-time water quality analysis and between them can
cover most of the relevant quality parameters. Technologies used in the water
industry include UV/Vis absorbance, fluorescence and NIR absorbance spectroscopy. Spectroscopic methods with potential for broader application include Raman
spectroscopy and laser-induced breakdown spectroscopy. All approaches share the
following properties: fully solid-state hardware, no reagents or other consumables
required for their operation, and automatic interpretation of the sensor data performed
J. van den Broeke (*)
KWR Water Research Institute, Nieuwegein, The Netherlands
e-mail: joep.van.den.broeke@kwrwater.nl
T. Koster
Enschede, The Netherlands
Andrea Scozzari, Steve Mounce, Dawei Han, Francesco Soldovieri,
and Dimitri Solomatine (eds.), ICT for Smart Water Systems: Measurements and
Data Science, Hdb Env Chem (2021) 102: 283–314, https://doi.org/10.1007/698_2019_391,
© Springer Nature Switzerland AG 2019, Published online: 31 August 2019
283