The main research focus of Fredriks PhD project include advanced treatment components for polluted stormwater. Coagulation/flocculation has been the primary focus so far.
Stormwater treatment is conventionally based on sedimentation processes to remove particulate matter in order to improve the water quality. However, recent research has shown that that the smaller particle fractions, that are less efficiently removed by sedimention, are important pollutant transporters. In order to attain adequate treatment effect, stormwater control measure design should include targeted removal of the smaller particle fractions.
Coagulation/flocculation is a treatment process that is ubiquitous in wastewater treatment and drinking water production, but very uncommon in a stormwater treatment context. Coagulation/flocculation has a proven ability to destabilize smaller particles, causing them to readily aggregate and settle out.
So far the PhD studies have aimed at investigating different research questions concerning coagulation/flocculation and its application as a treatment component for polluted stormwater. More specifically, the choice of coagulant, the coagulation characteristic and the dominating coagulation mechanism were investigated. Additionally the treatment efficiency of the most common pollutants in stormwater were determined.
Future studies to be included in the PhD thesis include the investigation of an innovative method to dewater stormwater sediment by utilization of polymers, as well as investigations into the use of electrocoagulation as a treatment method.