Nathanaël will investigate precipitation and blockages in urine-collecting pipes

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Hi! My name is NathanaĂ«l, but everyone calls me Nate, so feel free to do the same. I am currently interning with the Environmental Engineering Research Group at SLU for three months, and I’ll be here until July 26th. I come from Strasbourg, France, where I attend ENGEES (National School of Water and Environmental Engineering, Strasbourg). Our focus is on all aspects of water, from the smallest water cycles to the bigger picture. Next school year will be my final year before I become an engineer. My specialty is water treatment, and I aspire to work in wastewater treatment plants or in a design office that deals with their dimensioning or startup. This interest led me to contact researcher Prithvi Simha, as I found the subject of urine separation particularly fascinating and underexplored at my school. I’m currently working and learning with PhD student Christoffer Parrow Melhus on urine collection pipes. In these pipes, urea breaks down into ammonia and carbon dioxide, leading to precipitation that can cause complete blockages. On a personal note, I enjoy discovering new things and was actively involved in student life at my school, organizing events for my peers. In my spare time, I like to go fishing to recharge my batteries.

Ariane will work with Natnael on degrading pharmaceuticals in urine

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Hello everyone! My name is Ariane and I’m from France, where I have been studying water and environmental engineering for 2 years at ENGEES in Strasbourg. I did 2 years of preparatory classes in physics and chemistry to get into this school and since then I have discovered all the issues involved in managing water to protect the environment. I also chose to specialise in water treatment. I am at SLU for a three-month internship in the urine group, where I am taking part in a study looking at how to degrade pharmaceuticals in urine to create a safe fertiliser, which will give me my first experience of research.

New book chapter on impact of substrate on BSFL rearing

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We are happy to share our new publication “Advances in substrate source composition for rearing black soldier fly larvae as a protein source“, published as a chapter of the book “Insects as alternative sources of protein for food and feed”, published by Burleigh Dodds Science Publishing

In this chapter, Cecilia and IvĂŁ discuss some of the challenges faced by the BSF industry in relation to the feed substrates available for rearing this amazing insect species. Bioconvesion is affected by many variables and it is not easy to always have good predictability of the process and product composition combined with environmental sustainability.

We strongly believe that the real value of BSF larvae can only be extracted when waste streams are used as feed substrate (especially post-consumer waste) and when the larvae end up as feed for livestock. This, in our view, is the real path to sustainability!

 

Study visits in June

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We are not even halfway through June, and we already have two major highlights to share.

On June 5th, the Ambassador of Japan, Mr. Noke Masaki, visited us. Björn demonstrated the urine diversion toilet and explained the benefits of urine dehydration technologies. The Ambassador then came down to the BSF container, where Cecilia gave a short presentation of the technology and our research on the topic. Ivã and Viktoria then guided our visitors through the BSF lab, answering questions about the rearing and fertilising potential of the flies and their frass.

A week later, a joint delegation from Kenya-Lycksele came by for lectures from Björn and Cecilia, followed by visits to the urin diviring toilet and dehydration system, followed by a tour of the fly container, where Viktoria showed the eager participants around.

Knowing that our technologies and ideas gain international interest keeps us motivated to continue contributing to a circular society.

Study visit by EU ambassadors

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On April 23rd, representatives of the EU ambassadors came for a visit to the ET Department and had a pe[e]k at our urine diverting toilet where Björn and Prithvi talked ab   out the future of urine dehydration and the potential it harbours.

After the toilet, the visitors went on to our Black Soldier Fly container were Cecilia, in bitter cold winds, shared our vision on how to contribute to a circular food and feed production, if food waste would get accepted as a feed source for insects.

The evening ended with a dinner at the castle in Uppsala where ideas and visions for the future were exchanged.

Prithvi is now a Research Associate at the Gobabeb Namib Research Institute

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Prithvi Simha from our research group has been collaborating actively with partners in Namibia over the past three years. He has now joined the Gobabeb Namib Research Institute as a research associate/adjunct researcher. Gobabeb is a renowned center for dryland training and research located in the Namib Desert, approximately 120 kilometers southeast of Walvis Bay in Namibia. Prithvi in collaboration with Gert van der Merwe from Namibia University of Science and Technology, Eugene Marais from Gobabeb,a dn Christopher Malefors from SLU are running a joint project called “AirCloset” aimed at prototyping and evaluating a solar-thermal and wind-driven urine evaporator. Their goal is to develop a prototype evaporator that can effectively manage and utilize urine, transforming it into a valuable resource. Over the next nine months, they will pilot test the prototype evaporator at the Gobabeb Namib Research Institute. Gobabeb’s extensive weather station network and comprehensive environmental and meteorological data will play a crucial role in this phase. By leveraging these resources, they aim to gather detailed insights and refine the prototype for broader application. Stay tuned for updates on our progress and findings.

Selective degradation of endogenous organic metabolites in acidified fresh human urine using sulphate radical-based advanced oxidation

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The metabolome of real human urine is highly complex. Many of the organic compounds in urine significantly influence treatment parameters such as energy demand and product purity when urine is treated in resource-oriented sanitation systems. In a study  published in Water Research, Ali Mehaidli and Prithvi Simha from our research group developed a method using heat-activated peroxydisulphate for the selective degradation of organic compounds in human urine.

Key Findings

  • Optimal Conditions: The best conditions for peroxydisulphate activation in real urine were a dose of 60 mM, a temperature of 90°C, and a reaction time of 1 hour at a pH of 3.0. Under these conditions, over 90% of the peroxydisulphate was activated.
  • Selective Degradation: More than 150 organic metabolites were degraded in real urine, with a significant reduction in chemical oxygen demand and total organic carbon, indicating effective degradation of complex organic molecules.
  • Minimal Urea Loss: The process resulted in less than 10% loss of total nitrogen, with most of the urea remaining intact. This is crucial for maintaining the nutrient value of urine for recycling purposes.
  • Chloride Oxidation: The treatment did not oxidise chloride, suggesting minimal risk of forming harmful chlorinated byproducts

Hydrogen peroxide electrosynthesis in real human urine using a single chamber cell

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Researchers at Clemson University, the University of Cape Town, and the Swedish University of Agricultural Sciences have developed a new way to recover valuable nutrients from urine. This method, described in the journal Water Research, uses a special electrochemical cell that synthesise hydrogen peroxide in real human urine which stabilizes urea and alkalises urine to recover phosphorus as precipitates. The cell features a magnesium (Mg) anode and a carbon-based gas-diffusion cathode. The effectiveness of the process depends on the current density (the amount of electrical current per unit volume of urine). Lower current densities stabilize urea and facilitate the formation of struvite without significantly increasing the urine pH. Higher current densities produce more H2O2 but can cause the urine pH to rise too much, leading to the formation of less desirable calcium phosphate solids instead of struvite. Overall, the study provides a novel approach to stabilise human urine at source, without the need for physical dosing of chemicals, making nutrient recovery from urine more practical and safer. For more detailed information, the full study is accessible at:

Arve, P. H., Mason, M., Randall, D. G., Simha, P., & Popat, S. C. (2024). Concomitant urea stabilization and phosphorus recovery from source-separated fresh urine in magnesium anode-based peroxide-producing electrochemical cells. Water Research, 256, 121638.

 

New Installation Up & Running at SLU’s urine-separating toilet

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Exciting news! At the Swedish University of Agricultural Sciences (SLU), where all three of Sanitation360’s founders have studied and now work, a new bathroom installation has been in the works. And as of last week, after an incredibly impressive effort by Jenna, version 2.0 is finally ready to be used on the 5th floor at the Department of Energy and Technology at SLU in Uppsala, Sweden.

The bathroom contains one of Laufen’s urine-diverting toilets, which we’ve connected to our urine concentrator – and now we’ve also added our own addition to the flush system. Usually, both urine and 220 ml of flushwater end up being diverted into the urine collection tank, per flush. Whilst this is no issue in terms of purity, it is an issue in terms of energy usage later on in the urine to fertilizer process.

Urine consists of about 95% water, which contains no nutrients. Therefore, our urine concentrator is designed to effectively remove/evaporate the water, leaving us with the nutritious 4% of the urine. This is already a large amount of water to remove and with additional flushwater in the system, it rapidly increases the energy requirements. To make it more sustainable, we want to reduce, and favourably completely stop, any flushwater from entering the urine collection tank and instead divert it to the wastewater pipe. This is exactly what our new installation now does – thanks to Jenna and David Fredriksson at Davitor AB.

There is now a sensor that detects incoming flushwater and triggers the valve to the urine collection tank to close. The system also has a reactor with a level sensor to enable automatic pumping of urine into to the concentrator, where the urine is dried.

So if you ever happen to be in Uppsala, make sure to give it a visit and let us know what you think of it!

The white container on the right side is our concentrator which the urine is first diverted into and then dried into a nutrient rich mass. Attached to the wall behind it is our newly installed system which detects when someone is flushing and closes the valve to the urine collection tank. The program showcased on the computer shows how the different valves and sensors are working together to achieve this. Lastly, you can see Laufen’s beautiful urine-diverting ”Save!” toilet which we are big fans of!

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

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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.