Synergies Between Quaternary Treatment and the Removal of N, P, and BOD

Wastewater treatment plants today sometimes face both new and stricter discharge requirements. Are there synergies between different treatment technologies? How can we maximise the benefits of our efforts?

With the EU’s new Urban Waste Water Directive, new requirements for quaternary treatment to remove organic micropollutants are being introduced. These requirements apply to larger wastewater treatment plants serving over 150,000 population equivalents, as well as smaller plants with sensitive recipients. At the same time, stricter standards for the removal of traditional parameters such as nitrogen, phosphorus, and BOD are often imposed in Sweden. It will be a challenge for treatment plants to meet these stricter requirements while ensuring efficient resource use and minimal environmental impact.

Quaternary treatment is often implemented after biological and chemical treatment, which are crucial for the removal of nitrogen, phosphorus, and BOD. The way in which processes for these standard parameters are managed will affect both the results and environmental performance of quaternary treatment. At the same time, certain quaternary treatment methods will have an impact on the standard parameters. The purpose of this project is to improve the ability of treatment plants to select sustainable and cost-effective solutions when quaternary treatment is introduced alongside tightened requirements for existing parameters.

Since 2018, Sweden has carried out intensive development work on micropollutants, which has generated practical experience. Similar experience exists in other countries. The project will compile and process knowledge and experience from literature and existing plants, with a focus on ozonation and activated carbon. Literature reviews, site visits, and interviews with relevant facilities in Sweden and other European countries will be conducted. By engaging water and sewerage organisations with different types of facilities and experiences, the industry’s key concerns will be prioritised. A group of experts from industry and academia will contribute knowledge from their respective fields.

The results will be presented in an SVU report, summarising experiences to provide water and sewerage organisations with a broader knowledge base for continuing the work of implementing quaternary treatment.

Project Managers: Ann Mattsson, Envidan, ama@envidan.se and Rubén Juarez Cámara, Envidan, rjc@envidan.se