Nordic Grant: Supporting Sustainable Nutrient Recovery from Wastewater through Prospective Life Cycle Assessment
- Crónica do Investigador
- Feb 10
- 4 min read
Researcher’s Chronicle | Jade Müller is a MIT-Portugal PhD candidate at the Center for Industrial Ecology (CIE, ADAI-LAETA) at the University of Coimbra, where she focuses on developing and improving (environmental) life cycle assessment (LCA) approaches for emerging bioeconomy technologies. Her research integrates LCA with technical and socioeconomic indicators and multi-criteria decision analysis, aiming to support the development of more sustainable technologies. She was awarded the Nordic Grant 2024 to carry out the project "Supporting Sustainable Wastewater Nutrient Recovery through Prospective Life Cycle Assessment" during a research visit to the University of Southern Denmark and the University of Copenhagen, from November 2024 to January 2025. In this article, she shares her experience during this period.
"I thank the Portuguese Foundation for Science and Technology (FCT) and SPOT Nordic for this unique opportunity and financial support, and also the University of Southern Denmark and the University of Copenhagen for their hospitality and collaboration."
The Importance of Nutrient Recovery from Wastewater
Nutrients such as phosphorus (P), nitrogen (N), and potassium (K) are essential for agricultural production and global food security, particularly in light of population growth. New technologies have been developed to recover these nutrients from wastewater, generating secondary fertilizers for agriculture. These technologies offer benefits such as reducing nutrient discharge into the environment—which causes eutrophication—preserving finite mineral resources, and decreasing dependence on imported fertilizers. However, these processes require resources like energy and materials, and therefore also generate environmental impacts that must be carefully assessed.
Life Cycle Assessment as a Tool to Support Technological Development
The development of new technologies involves decisions that shape their future environmental impacts. Life Cycle Assessment (LCA) is an essential tool based on quantifying resource use and emissions throughout the product’s life cycle—from raw material extraction to disposal. This data-dependence makes LCA particularly challenging for emerging technologies (e.g., at lab scale), due to limited information on their performance, applications, and more¹.
My PhD research at the Center for Industrial Ecology (CIE-ADAI), University of Coimbra (UC), focuses on improving the LCA of new technologies aimed at the bioeconomy and waste valorization. Among these, nutrient recovery technologies from wastewater are a central theme of my visit to Denmark.
Research Visit to Denmark through the Nordic Grant
With the support of the Nordic Grant, I began my visit to Denmark in November 2024. The mobility period aimed to:
Develop a harmonized approach and life cycle models to compare two nitrogen recovery technologies (ammonia stripping-scrubbing and ion exchange/adsorption);
Simulate the application of recovered fertilizers in agricultural fields using specialized tools;
Disseminate research findings.
I worked closely with two groups: Life Cycle Engineering (LCE) at the University of Southern Denmark (SDU) and the Department of Plant and Environmental Sciences (PLEN) at the University of Copenhagen (KU). These teams, together with our UC group, are involved in the Horizon 2020 project “WalNUT – Closing waste water cycles for nutrient recovery,” funded by the European Union.
In the first phase of the visit, I was based at SDU in Odense, collaborating on an LCA study comparing nitrogen recovery technologies. This required aligning methodological choices and adapting to a new approach.
The LCA community in Denmark adopts a consequential approach, while in Portugal the attributional approach is more common. I also organized a training session on a scenario modeling tool for future LCA, led by its author (Sommer Schjønberg et al., publication in progress).
In the second phase, I was based at KU in Copenhagen, working from a different perspective—agricultural sciences. KU developed the tools PLCI 2.0² and Daisy³, which simulate agricultural systems and model phosphorus and nitrogen flows, providing valuable inputs for LCA. I used PLCI 2.0 to test scenarios of applying phosphorus-based biofertilizers in different EU countries, assessing their potential to substitute mineral fertilizers. This posed challenges, as the model is calibrated for Danish agriculture. Thus, adaptation strategies were discussed with KU researchers and are currently being tested.
During my stay, I also visited the Department of Environmental Sciences at Aarhus University, in Roskilde. Professor Pedro Carvalho welcomed me and provided a tour of the laboratories, introduced me to other researchers, and presented the group's ongoing projects. This was a valuable opportunity to explore work aligned with my research interests, particularly in water treatment and management technologies.
The mobility period in Denmark was enriching for my academic and professional journey. It provided significant progress in my research and strengthened my technical and analytical skills to address complex sustainability challenges. During this time, I advanced two scientific manuscripts and submitted an abstract for an international conference. The visit also allowed me to expand my professional network and consolidate important collaborations between research groups in Portugal and Denmark.
References:
Müller-Carneiro et al. (2024). Ex-Ante Life Cycle Assessment of Emerging and Novel Technologies. https://doi.org/10.1016/B978-0-323-90386-8.00092-9
Rydgaard et al. (2024). Regionalised modelling of recycled fertiliser P in agricultural fields: Development of the life cycle inventory model PLCI 2.0. https://doi.org/10.1016/j.jclepro.2024.141088
Abrahamsen & Hansen (2000). Daisy: an open soil-crop-atmosphere system model. https://doi.org/10.1016/S1364-8152(00)00003-7
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