Visit to Norvatten, Stockholm

Drinking water utility Norvatten wants to modernize its treatment process for the increasing population of Stockholm, and to provide additional disinfection and removal of organic micropollutants. They asked KWR for some independent advice as to how to select the technologies that should be compared in pilot research.

Norvatten drinking water utility in Stockholm

The city of Stockholm and its surroundings have two drinking water utilities: Stockholm Water (providing water for about 1.4 million people in the center and southern part of the city) and Norvatten (providing drinking water for about 600,000 people in the north of the area). Norvatten has to modernize its treatment processes in order to be able to provide water for the increasing population in the area, and to incorporate additional disinfection and removal of organic micropollutants. The source is lake Mälaren, one of the largest lakes in Europe with a surface area of 1100 km2.

New treatment processes

In order to select the most suitable treatment processes, Norvatten wants to do some pilot research, comparing several techniques. So far they have been discussing this with several technology providers, but they were looking for some independent advice. Technologies they are interested in are several membrane processes (ultrafiltration and microfiltration), ion exchange processes, ozonation, advanced oxidation (O3/H2O2 and UV/H2O2), and filtration over granular activated carbon.