The wastewater is treated with mechanical, chemical and biological methods and then passes through the sand filtration process that filters out the remaining small particles. The whole purification process takes 24 hours. The treated water is discharged into the Baltic Sea.
Less impact on the environment
Stockholm Vatten continuously works to reduce the impact that the organic substances, phosphates and nitrogen will have on the environment. At least 95 percent of the organic substances and 98 percent of phosphates, plus at least 50 percent of the nitrogen are removed during purification, thus satisfying the demands of the authorities.
Work to reduce rubbish and environmental toxins
Every week 32 tons of trash, which has been flushed down the toilet, ends up in the sewage treatment works in Stockholm. To reduce the amount of trash, as well as the environmental toxins that may disturb both the processes in the treatment works as well as the aquatic environment, measures are continuously taken to improve the treatment process and prevent the toxins and trash from ending up in the wastewater. One of the measures has been public campaigns with the aim, for example, to convince the population to use eco-labelled products and to use a waste-paper basket instead of flushing trash down the toilets.