Fredrik Nyström

About me

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 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.

After the licentiate degree, Fredrik has in a study investigated how the choice and preparation of polymers affect a dewateringprocess of stormwater sediment from a stormwater pond. The study will result in two articles, where the first one will focus on the polymer demand and the treatment performance of the filtrate, i.e. the reject water that is returned to the pond in the dewatering process. The second article will focus on aspects of dewaterability of the stormwater sediment in relation to the polymer and the preparation.

In addition to the projects included in the PhD studies, a smaller study on the performance of electrocoagulation as a treatment process for stormwater was investigated. Specifically, the treatment performance and how it is affected by different current levels and material choice for the electrodes.