Genomljusning – Optical sensors: the incoming future for process optimization in drinking water treatment plants

Last changed: 07 January 2020
A glass of water. Photo.

The Genomljusning project aims to improve the treatment of surface water for drinking water production using different optical, chemical and physical sensors along the treatment process.

In Sweden an increasing trend of natural organic matter (NOM) in surface water has been observed, which may cause problems for the production of drinking water. High concentration of NOM can affect the taste and odor of the produced water, growth of bacteria, viruses and parasites, as well as the formation of carcinogenic disinfection byproducts (DBPs).

NOM fluctuations in raw water and process water follow natural mixing in lakes and storm or snow melting events in running water. During these periods of the year, the drinking water plants can be faced with operational problems. NOM fluctuations can be easily followed using optical sensors, together with physico-chemical sensors. However, they are used only in a few, mostly larger, waterworks in Sweden.

Our research aims to:

  • achieve a good and steady process water quality using sensors with respect to color and NOM concentration and composition in different types of raw water;
  • reduce the use of precipitation chemicals and thus sludge production through optimized dosage;
  • optimize the operation of active carbon filters, membranes and managed aquifer recharge;
  • establish quality insured measurements and evaluation procedures using in situ sensors.

The project is financed by SLU, the Swedish water and waste water association, DRICKS, SafeDrink, DigiDrick and a cooperation of eight utilities in Sweden (Borås Energi och Miljö, Gästrike Vatten, Göteborg Kretslopp och Vatten, Norrvatten, Sydvatten, Tekniska Verken, Uppsala Vatten, VIVAB). The project runs in cooperation with Kathleen Murphy at Chalmers University, Göteborg.

An optical sensor. Photo.
Optical sensor in raw water monitoring. Photo: Claudia Cascone
The different steps in the water cleaning process and where sensors can be placed to measure natural organic matter. Illustration.
Sensors along the drinking water treatment process. Figure by Stephan Köhler and Claudia Cascone.