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Production of nitrogen, phosphorus and carbon from waste water


Municipal sewage and some industrial waste waters can be used as sources of carbon and nutrients much more effectively than they are today. VTT Technical Research Centre of Finland considers waste water to be a feedstock from which these valuable substances can be extracted in a form suitable for various applications. VTT is now promoting this idea with the help of the Resource Container project, aiming at small-scale waste water treatment solutions.

According to studies conducted by the Finnish Innovation fund Sitra, the value of nutrients and carbon lost in waste water treatment processes in Finland amounts to several million euros. Efficient nutrient recycling would reduce the nutrient burden causing eutrophication, and the harmful climatic effects caused by production of mineral fertilisers.

VTT has designed a Resource Container concept that consists of physico-chemical methods used or under development in the industrial sector. They will be combined in such a manner that the focus of substance extraction will be specifically on the products (nutrients, bio-carbon and clean water), rather than on their disposal. The operating model does not include biological treatment, and can therefore be flexibly implemented in various scales locally or as a seasonal solution.

"This year, we will test the concept at the waste water treatment plant of the town of Parainen. We also intend to study its functionality in archipelago conditions, where the challenge is to guarantee functional waste water treatment for a few dozen households and facilitate potential utilisation of the purified water, e.g. for irrigation," says Mona Arnold, Business Development Manager from VTT. 

In the follow-up project, VTT will ensure functionality of the sub-processes and make preliminary investment and operating cost calculations for the best comprehensive solution. The best technologies will be incorporated into a mobile waste water treatment container that can be used in small-scale waste water treatment projects. With the help of this container, Finnish companies can demonstrate the technological strengths of their products and thus improve their business opportunities on the international markets.

The results of the project will especially benefit municipal waste water treatment plants, technology suppliers, the chemical industry, and producers of recycled nutrients and soil improvers. The project will generate information about innovative treatment solutions and recovered nutrients, carbon and other products for the use of such operators.

The Resource Container project, included in the Ministry of the Environment's Raki2 programme, was launched on 1 December 2016 and will end on 31 December 2017. In the first phase, it is funded by the Ministry of the Environment and VTT. In addition to the parties mentioned above, other members of the steering group are Sofi Filtration, Aquaminerals, Owatec Group, Kemira, Dewaco, Econet Group, BSAG, the town of Parainen and Pöyry. VTT's share of the project is the design, definition and testing of waste water treatment concepts and their techno-economic evaluation. 

Valuable substances found in waste waters include carbon, phosphorus, nitrogen, water and metals

  • Carbon recovery would enable the production of energy products, soil improvers and oil alternatives.
  • Recycling of phosphorus is vital in food production. Phosphate rock has identified as critical raw material.
  • Nitrogen is a major environmental threat to water systems and nitrogen recycling saves energy.
  • Production of fresh water from waste water is considerably cheaper than from sea water.
  • The recovery and recycling of minerals, such as potassium and magnesium, will be increasingly important in the future.