SLU news

New grips to purify water

Published: 22 March 2022

At the beginning of April, Malin Ullberg will defend her dissertation. The dissertation contributes with new findings on how different processes with granular activated carbon can be used under different conditions to treat water. The work behind the dissertation is an input for protecting human health in the future.

In the work on the dissertation, Malin has investigated the effects of combining different processes and what role they can play in the production of drinking water. Malin used two different ways to perform experiments. They were set up at two existing drinking water treatment plants in Sweden, one in Stockholm that treats water from Lake Mälaren and one in Uppsala that purifies groundwater. The treatment plant in Uppsala has a known problem with high levels of several PFAS (per- and polyfluoroalkyl substances).

According to the UN, safe and clean drinking water is a fundamental human right and should be accessible to all. However, lakes, rivers, and groundwater around the world are increasingly negatively affected by the widespread use of artificial chemicals, such as medicines, per- and polyfluoroalkyl substances (PFAS). In nature, PFAS and other chemicals used in industrial production are largely indestructible. These pollutants are released into the environment in different ways. At high concentrations, they can pose a threat to wildlife, the environment, and human health. PFAS in particular has received a lot of media attention, as exposure (through drinking water) has been linked to certain cancers and to reproductive problems.

Since such compounds inevitably end up in water intended as drinking water, they must be removed in drinking water treatment plants to make the water safe for human consumption. Through the work on her dissertation, Malin has shed light on how granular activated carbon can be used in purification. Many unwanted chemicals are not easy to remove with conventional treatment techniques. Therefore, new treatment steps are needed that are tailored to remove these substances.