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Regional wastewater turns into an energy resource


Detailed description of the Good Practice

In 1999, the Turku City Council made decision to build a new regional waste water treatment plant and it would be placed in the rock of Kakolanmäki (former prison area in Turku) in the very centre of Turku. Over ten years of work the plant has been finished and now most part of the waste water produced in Turku region is directed to the Kakolanmäki. After the decision of the City Council it took almost 5 years of completing all the permits needed for construction. The investment cost was about 128 M€ and included all construction costs as well as waste water transport pipes in the Turku area.
In 04/2009 a new waste water plant in Kakolanmäki started to operate and it replaces five old plants. The total treatment capacity of the plant is projected for 300000 people that means that the capacity also includes waste water treatment for several neighbouring municipalities.

In addition to the new technology and improved treatment quality as it meets all environmental standards of the HELCOM Recommendation 28E/5. The innovative aspect is focused in the concept of efficient partnership between the waste water treatment plant, the heat recovery company Turku Energia Ltd. and a biogas producer Biovakka Ltd.

The treatment plant was built in the city centre of Turku, tens of meters under the rock. At first the location of the plant was criticised for being in the very centre of the city as a source of possible smell or noise problems but these problems have not occurred and aren’t foreseen.

Treated water of the plant can now be released to the Baltic Sea without any harm to the coastal waters. All the contaminants in the waste water organic matter and pathogens are removed from the treatment process as sludge. Sludge, in its turn, is refined into biogas and the residue from that process is used as a fertilizer, while biogas is used for electricity and heat (see article in Baltic Cities Bulletin 2/2009 for more information).

The heat recovery system is also installed in the treatment plant and used for the district heating. Furthermore, cold water is also collected and used in the district cooling network in some hospitals and office buildings. The former problems are solved by combining problems and turning them into a resource. The Resource gives the community an opportunity to use less fossil fuels and offers a real solution for management of the growing waste sludge problem. Refining of the waste water into energy and fertilizers provides additional working places and incomes to the local area. There is less need for mining phosphate when sludge is used as a fertilizer.

waste water management
climate change
energy efficiency
stakeholders involvement

Objectives of the Good Practice

to create a modern waster water treatment plant that does the Baltic sea with minimal harm and the refined sludge of which can be used as a source of energy and fertilizers.

Participants of the Good Practice

Kakolanmäki waste water treatment plant, the heat recovery company Turku Energia Ltd. and a biogas producer Biovakka Ltd.

Funding of the Good Practice

Turku City Council

More Details of the Good Practice

Available files

Contact details

Kakolanmäki waste water treatment plant

Data sources and references

Baltic Cities Environmental Bulletin 1/2010