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Nutrient recovery in Turku, Finland

Last updated: Jan 11, 2022

Summary

In Turku, even sludge does not go to waste. Sludge, a by-product of the city’s wastewater treatment, is processed with anaerobic digestion. Besides producing biogas, which is used to help power transport in the city, nutrients recovered from the process are used in landscaping and agriculture, which reduces reliance on fertilizers.

Problem

Until 2009, wastewater was collected separately by fourteen municipalities in the Turku region. Nutrients capture wasn’t maximized which was causing the Turku marine area to be substantially polluted with phosphorus and nitrogen. As for drinking water, it used to be produced by separate water production facilities using either groundwater or surface water obtained from small rivers nearby Turku. The quality and quantity of the river water was not sufficient. As a result, drinking water in the Turku.

Solution

Turku acknowledged the need to reinvent water management in the region to both improve the water quality and protect local ecosystems. Today, sludge, a by-product of the city’s wastewater treatment, is processed with anaerobic digestion.

Outcome

Besides producing biogas, which is used to help power transport in the city, nutrients recovered from the process are used in landscaping and agriculture, which reduces reliance on fertilizers.