Treatment of road-runoff with Dual Porosity Filtration (DPF), Lynge, Denmark
In the last decades, there has been a tendency towards separating the discharge of rainwater and household wastewater. Although this was also the case in the project “Lynge Nord”, the Municipality of Alleroed, north of Copenhagen, also wanted to create a new blue and clean habitat with water from road runoff. Since road water runoff is contaminated with fine particle materials as well as dissolved substances, a purification solution was necessary. The process, Dual Porosity Filtration (DPF), was developed in 2001 by Professor Marina Bergen Jensen and has since then been tested in different places in Denmark. It is now a well-documented technology with results from more than 40 stormwater events.
Watercare Filtration has industrialized the product. The processes of purifying the water in DPF are sedimentation, adsorption, and biodegradation. Less than 5 mg/l suspended solids (SS)  can be expected from DPF. Particles larger than 2µm will be removed creating crystal clear water after the purification processes. The removal of heavy metals and phosphorus is significant compared to other solutions on the market.

Dual Porosity Filtration is inspired by nature and requires no power and no chemicals. It makes no noise and doesn't smell and the process has a capacity from 3 litre per second to 100 litre per second.