Outotec to build sewage sludge thermal treatment plant in Switzerland

Outotec OYJ, a Finland-based provider of solutions for the mining and metallurgical industries, has won a contract worth €50 million ($63.75 million) to build the advanced sewage sludge thermal treatment plant in Switzerland.

The contract has been awarded by City of Zürich (represented by Entsorgung und Recycling Zürich). The value of the contract, of which the first phase engineering will be included in Outotec’s 2012 order intake, and the main delivery contract, subject to a mandatory referendum by the people of Zürich, will be booked in the second quarter of 2013.

Outotec’s solution is based on advanced fluidized bed technology. The new sludge thermal treatment plant in Werdhölzli will treat all the sewage sludge produced in the Zürich region, annually 100,000 tonnes, and generates 875kW of electrical power and 4,450kW of heat.

The plant complies with the most stringent European and Swiss emission limits. Outotec will deliver the plant on a turnkey basis and is scheduled to be commissioned in 2015.

The Werdhölzli plant is designed as a mono sludge incineration plant. A phosphate recovery process, such as the Outotec ASH DEC process, can be added to the plant in future. The ASH DEC technology, acquired by Outotec in 2011, complements Outotec’s biomass incineration solutions.

The method is used to extract phosphorus fertilizer from ash produced in sludge incineration. Integrating the ash-to-fertilizer process into sludge incineration, the plant enables the recovery of energy and valuable nutrients from biomass and sludge in a single, sustainable facility.