FÖRSEDIMENTERING OCH FILTER VID DAGVATTENRENING I FÖRORENINGSBELASTADE OCH TRAFIKTÄTA OMRÅDEN / Pre-sedimentation and filter for stormwater treatment in traffic dense areas with high pollution load

The EU Water Directive (2000/60/EG) refers to 1991/271/EEC in regards to runoff water (storm water) as a type of sewage water. The EU Water Directive also points out the urban road runoff water as a pollutant source for ground water. Elevated levels of pollutant concentrations can be found in runoff water from catchment areas with dense traffic loads. Depending on road maintenance, use of studded tires, type of pavement, traffic load, velocity, type of vehicle, residential and industrial areas and tunnels, the degree of mobility of the pollutants will vary in the ambient air and the runoff water. An aspect that only to some extent has been elaborated on is the influence of pavement type and its wear with regards to the mobility of the pollutants. A possible treatment
technique for polluted runoff water is the use of sedimentation and a filter for removal of dissolved and colloidal substances utilizing a batch sequenced mode of operation. The successful application of a batch sequenced treatment technique would depend on the “First flush” behavior of the catchment area. Along the Essingeleden motorway in Stockholm, with a yearly average traffic load of 120 000 vehicles per day, field trials and investigations of the treatment technique and first flush behavior is carried out along with assessment of generated sludge from storm water.