An urgent call for using real human urine in decentralized sanitation research


The choices we make matter. The choices we make as scientists can significantly impact society. In this perspective article published in Frontiers in Environmental Sciences, Caitlin Courtney, Dyllon Randall and I focus on one such methodological choice in decentralized sanitation research: whether to use real human urine or synthetic/artificial urine for experimentation.

For various reasons, many studies opt for synthetic urine over real human urine, relying on recipes for making synthetic solutions that mimic real urine. Using synthetic solutions as stand-ins for real fluids is a legitimate scientific method, and one that is not uncommon in wastewater research. But exclusively using synthetic urine can present methodological challenges, especially when protocols for its preparation are not well-established and validated against real urine. This article highlights some of the compositional and property differences between synthetic urine and real urine, and the implications of these differences on experimental outcomes and their real-life implications.

We hope this article sparks a dialogue within the research community on the benefits of using real urine in experimental research. We strongly encourage researchers involved in this field to collaborate in establishing standardized terminology, definitions, methodologies, and best practices for sanitation-related research involving human urine.

If you are interested in furthering this effort, please do reach out to us!

Simha, P., Courtney, C., & Randall, D. G. An urgent call for using real human urine in decentralized sanitation research and advancing protocols for preparing synthetic urine. Frontiers in Environmental Science, 12, 1367982.

Oliver is back at SLU for his thesis project!


My name is Oliver. Currently, I am in my final year of studies at Tampere University of Applied Science. My association with the urine drying team dates back to the summer of 2022. During that period, I was involved in researching various methods for the acidification of urine. The primary objective of this research was to prevent the process of enzymatic urea hydrolysis, thereby preserving nitrogen in urine. I have now returned to SLU to write my BSc thesis, where I will focus on exploring techniques for the removal of organic micropollutants. These pollutants, can have significant environmental impacts, especially in aquatic environments. Through my research, I aim to contribute to the development of more sustainable and effective waste management practices.

Microbes In Focus: Isis Conroy’s Return to SLU


Hi, I am Isis Conroy. I am in the final year of my bachelor’s degree in environmental engineering at Tampere University. Last year, I was at SLU working alongside Natnael Demissie with lab duties relating to his doctoral thesis which evaluated the effect of UV and peroxide on antimicrobial-resistant bacteria and their genes. This year I have returned to do my own thesis working on a project that aims to standardize a methodology for assessing urea hydrolysis in urine by utilizing bacterial urease rather than jack bean urease. In both my work and hobbies, I enjoy microbiology, microscopy, and mycology. In my free time, I am a mushroom guide, teach microscopy lectures to children, and I enjoy spending time outdoors. I will be at SLU until I present my thesis in early June.

The AirCloset project!


The SLU Urban Futures hub in Ultuna has granted funding to three interdisciplinary projects focusing on the Urban Food-Energy-Water nexus, one of which is called “The AirCloset” that will be led by Prithvi Simha from SLU, Sweden and Gert van der Merwe from NUST, Namibia.

The Air Closet and Granurin Technology:
The project will pioneer the development of a toilet that separates and dehydrates urine using solar-thermal energy. This not only provides a sustainable solution for sanitation in informal settlements but also presents a unique opportunity for recycling urine into a great fertilizer – Granurin.

Granurin, a Fertilizer Revolution:
Granurin, with its 20% nitrogen content, represents a revolutionary step in sustainable agriculture. Simha and his colleagues at SLU have successfully developed a technology to dehydrate urine, creating these safe fertilizer pellets that can potentially replace synthetic fertilizers. This not only contributes to circular food production but also opens up a global avenue for local food security enhancement.

Impact on Urban Informal Settlements:
Taking the technology a step further, the project aims to implement urine drying in urban informal settlements, where over a billion people reside without access to basic services. By providing a solution that integrates sanitation, agriculture, and economic empowerment, The Air Closet challenges the status quo, striving to uphold the promise of Agenda 2030 – “leave no one behind.”


FoodsecURe: Food security through better sanitation


FoodsecURe: Food security through better sanitation is a NRC funded 4 year research project (2023-2027) that targets the small-scale producers around the outskirts of Bahir Dar city who also participate in the on-going EU H2020 funded project “Healthy Food Africa” (HFA). FoodsecURe is coordinated by NIBIO with Dr Divina Gracia P. Rodriguez as Project Manager, with partners including the Kretsloppsteknik group at the Swedish University of Agricultural Sciences (SLU), the Norwegian University of Life Sciences (NMBU), Norges Vel, Bahir-Dar University (BDU), and Amhara Regional Agricultural Research Institute. BDU office of the Healthy Food Africa project, Bahir Dar City Water Supply and Sewerage Authority, and the Bureau of Water and Energy are key stakeholders and members of the Advisory Committee of the project from the Ethiopian side.

Degradation of poly-L-lactic acid biopolymer films in Ca(OH)2-dosed fresh human urine


We have recently published a paper in Resources, Conservation and Recycling which looks into the possibility of using Poly-L-Lactic Acid (PLLA) biopolymer to capsulate and safely dose chemicals to human urine.

Alkaline dehydration of urine for recycling of plant essential nutrients requires fresh urine to be stabilized with alkali or metal hydroxides. Improper handling and exposure to these chemicals may cause skin or breathing irritation. Therefore, if these chemicals are wrapped inside capsules made of a biopolymer, human interaction with these chemicals can be minimized and chemicals could be passively dosed to urine. These capsules can also be used for dosing of oxidants and peroxides for the removal of micropollutants and pharmaceuticals from urine.

In the study, degradation of PLLA films in Ca(OH)2 dosed fresh urine was evaluated with temperature, thickness and pH being the variables. The results of this investigation provided some really interesting results in terms of physiochemical changes in the urine and the physical, chemical and molecular changes of the films. If you are interested to find out more and read the full article, click here: .

Approaches for bridging the sanitation delivery gap in urban informal settlements in Namibia

PC: The Namibian

Shack dwellings in informal settlements are home to a billion people worldwide. In Namibia, 40% of the population currently live in shacks. These settlements often lack land tenure and governments do not have capacity to invest in infrastructure in unplanned spaces. Therefore, they are not connected to centralised sewage systems and on-site decentralised sanitation becomes the norm.

In a paper published in the journal City and Environment Interactions, Gert van der Merwe and I explore this grey zone of urban informality and the gap in sanitation delivery in Namibia. We evaluate how local communities, non-government organisations (Clay House Project and Development Workshop Namibia) and an international development agency (GIZ Namibia) interact and navigate the physical, economic and political landscape of implementing bottom-up sanitation solutions for informal settlements. In critical analysis of the three different sanitation delivery models of these organisations, we consider their historical development, underlying philosophies and technical solutions. We also examine how products from different sanitation systems are managed and whether urine source separation could improve their management.

Urine recycling featured in flagship report of the UNEP and Global Wastewater Initiative


The flagship report of the UN Environment Programme (#UNEP) and Global Wastewater Initiative (#GWWI) was recently released at the #WorldWaterWeek in Stockholm a few days ago! Prithvi Simha from the group contributed to the report as one of the authors.

This new report, “Wastewater – Turning problem to solution” urges decision makers and action takers from all regions of the world to implement the three key actions, to overcome some or all seven barriers, and to put in place all or some of the six building blocks, described in the publication.

The report features SLU – Swedish University of Agricultural Sciences and Sanitation360 AB‘s work on #urine #recycling in the form of three case studies:
1. Producing urine-based fertilizer on the island of Gotland, Sweden (work from our #N2brew and P2GreeN #EUH2020 projects)
2. Urine separation – Alkaline dehydration in practice in #Malmö, Sweden (work from our REWAISE EU project)
3. Social barriers to urine recycling in decentralized sanitation systems.

Welcome Jacob Fager!


Hi, my name is Jacob Fager. I’m stationed on Gotland and my main task is to collect urine. I used to be a soldier since I finished school 2016 but now I’m about to study to become a farmer. I grew up on my family’s farm, so it has always been in my interest. While I’m waiting on my studies to start I will be helping this interesting project and hoping I will lucky to be able to use human urine fertilizer on my future farm.

New PhD candidate on concentrating acidified urine in P2Green project, welcome Ya Gao!


Ya Gao comes from China and previously received her Master’s degree in Environmental Technology at Wageningen University and Research in the Netherlands and her Bachelor’s degree in Environmental Sciences at Tongji University in China. After the graduation from her previous study, Ya Gao worked in a green building sustainable consultancy company in Shanghai as a project engineer for one and a half years. In May 2023, Ya Gao has joined the Kretsloppsteknik group as a PhD student working for the EU project P2Green. The main focus for her PhD study will be the urine dehydration research that aims at dehydrating the acid-stabilized human urine and recovering the nutrients contained in the urine for the use of plant fertilizers.