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University of Tartu: Pallet of solutions for nutrient recycling

6 May, 2020 - 14:31

One of the main outputs of the BSR WATER project is the “Pallet of solutions for nutrient recycling in the Baltic Sea region”, foreseen as an integral part of the HELCOM Regional Nutrient Recycling Strategy. The pallet of solutions is a compilation of most recent knowledge and practice on advanced and efficient solutions to recycle nutrients, and in particular phosphorus from wastewater.

While phosphorus is a recognized pollutant for the Baltic Sea region, it is also part of many organic molecules and is vital and irreplaceable for all lifeforms. Phosphorus is an essential and limited resource, classified as a critical raw material by the European Commission. Natural reserves of phosphate rock are concentrated in limited number of countries such as China, Morocco and the US. As the population grows, the phosphorus demand and production in the world is also steadily increasing and the management of phosphorus must be transformed from linear to circular in order to retain the safety of our economy and food. The efficient use of natural resources is also one of the main factors of becoming a sustainable society, therefore coupled with the environmental issues, reuse and recovery of phosphorus needs to be one of our main goals for the near future. One of many measures for reducing dependency is the recovery of phosphorus from available national sources such as municipal and industrial wastewater.

As wastewater is one of the main flows of nutrients, wastewater treatment plants should be viewed as a key location for nutrient recovery operations. Presently, phosphorus and nitrogen are removed from the wastewater, but in most cases the nutrient-rich sewage sludge is not used further due to possible problematic heavy metal and micropollutant concentrations. Many new and emerging technologies tackle this issue and aim toward extracting nutrients from these waste streams, while leaving the pollutants behind. These technologies are currently evaluated in various full, pilot and laboratory scale tests around the world to find most efficient parameters for operation, possible limiting components in the input streams and above all else the financial implications of the processes.

The pallet of solutions includes overview of the global situation in nutrient production and use, main pathways of nutrients transportation to wastewater, flow schemes of nutrients in the wastewater treatment plant and technologies for integrating nutrient recycling from either liquid or sludge matrices into the treatment process. Downstream recovery methods from treated sludge or incineration ash are also discussed. For each of the main technology types, an example case of a full-scale or a pilot-scale application is included, with overall evaluations of potential environmental risk and financial feasibility rounding out the document. The pallet of solutions itself is the final part of the document, summarizing all previous information and reforging it into a clear and concise format.

The “Pallet of solution for nutrient recycling in the Baltic Sea region” is expected to be published in the beginning of summer! We look forward to sharing our work with you!

 

Markus Raudkivi
University of Tartu