Tag Archives: Source-separating sanitation systems

PhD Defence of Prithvi Simha on Alkaline Urine Dehydration, 2nd of June

The public defence of the doctoral thesis for Prithvi Simha, entitled “Alkaline Urine Dehydration. How to dry source-separated human urine and recover nutrients?” is scheduled –

When? 2nd of June at 13:00 Where? Room Framtiden at MVM-hus at SLU in Uppsala and via Zoom Click this URL to join via Zoom: https://slu-se.zoom.us/j/69422000884 with Passcode: 732271

External reviewer: Professor Nancy Love, Department of Civil and Environmental Engineering, The University of Michigan, Ann Arbor, USA.

Examining committee: Professor Annelie Hedström, Luleå University of Technology, Luleå, Sweden; Docent Sebastian Schwede, Mälardalen University, Västerås, Sweden; and PhD Surendra Pradhan, University of Eastern Finland, Kuopia, Finland

The thesis is openly available at: https://pub.epsilon.slu.se/23473/1/simha_p_210511.pdf

Continue reading PhD Defence of Prithvi Simha on Alkaline Urine Dehydration, 2nd of June

Professor installation lecture

At the end of April all new professors at SLU were having their installation lectures. A totally new concept with online lectures and the audience could ask questions online. Björn gave his lecture with focus on how we in the future can decrease the emissions to the environment by disconnecting us from the water and wastewater system and instead use the same water in the house by cleaning and reusing it at the same time as we produce a clean fertiliser out of the toilet fraction. In total 147 people were attending the lecture. It is still possible to follow the lecture at the following link: https://youtu.be/EYtuP0ino3M?t=15148

Contact: Björn Vinnerås

New master student writing thesis about

My name is Linnéa and I am doing my master thesis at Uppsala University (UU) and the Swedish University of Agricultural Sciences (SLU). I am currently in my last semester as a civil engineer in molecular biotechnology at UU. I was born and raised in Västerås but have lived and studied in Uppsala since 2016. I had never been to SLU before my master thesis, so I think it is exiting to discover new environments and meet new people during my semester here writing my master thesis!

My thesis is a collaboration between UU, SLU and two companies called Nanoform Science and Sanitation 360. Nanoform Science is a company that has developed a technology for manufacturing very acidic metal oxide surfaces which should have antimicrobial properties. Sanitation 360 is a company that wants to turn human urine into dry fertilizer by using treatment systems in connection with urine-separating toilets. These two companies are both interested in investigating the properties of these very acidic metal oxide surfaces. Nanoform Science wants to investigate whether the surfaces have antimicrobial activity, since they thereafter could develop the surfaces into environments where biofilms thrive, e.g. hospitals, dental clinics and sewage systems. Sanitation 360 is interested in the surfaces since biofilm growth in their treatment system leads to loss of nutrition in their fertilizer product.

During my work, I will mainly focus on developing a method for growing urease-positive biofilms, then I want to test the method on the surfaces from Nanoform Science.

Welcome to our new PhD-student, Abood!

Hi! My name is Abdulhamid Aliahmad, and since it’s hard to read and pronounce my name correctly, I go by Abood. I am an environmental engineer with multi environmental backgrounds gained through my bachelor’s degree, a 9-month internship, and two former jobs in Palestine focusing mostly on sanitation.  I have recently earned my master’s degree in energy & environmental engineering with focus on Sustainability Engineering from Linköping University and my thesis has been carried out together with Volvo Construction equipment in Carbon Neutrality domain using GHG Protocol.

Most recently, I was fortunate to become a part of the environmental engineering group in the Department of Energy and Technology at SLU as a new doctoral candidate working with Jennifer as my supervisor. My contribution to the project will be;

  • sustainability assessment for the nutrient recovery technologies from sanitation, mostly urine. The assessment will be performed using TIS (technology innovation systems), LCA (life cycle assessment) tools, and possibly QMRA (quantitative microbial risk assessment).
  • multi-criteria sustainability assessment of systems will be performed using case studies.

Prithvi Simha’s pre-dissertation PhD seminar

On 5th of March, Prithvi had his pre-dissertation seminar: Alklaine Urine Dehydration – how to dry urine and recover nutrients. David Gustavsson from VA SYD/Sweden Water Research was Prithvi’s opponent at the seminar and he quizzed Prithvi on his published papers as well as his preliminary thesis (or kappa). Overall, it was very interesting and long discussion ranging on topics like reactive nitrogen and ammonia capture, the use of different alkaline substrates, the use of IoT in sanitation and global sanitation outlook. With this successful seminar, Prithvi will now proceed further and have his PhD defence which is scheduled to be held on the 2nd of June in Uppsala and via zoom online. We thank David again for his thorough and insightful discussion on the topic!

Using MgO for Alkaline Dehydration of Human Urine Collected in Source-Separated Sanitation Systems

We recently published a new paper on the use of Magnesium Oxide as an alkaline substrate for dehydrating urine in the journal Frontiers in Environmental Science.


Abstract: Fresh human urine, after it is alkalized to prevent the enzymatic hydrolysis of urea, can be dehydrated to reduce its volume and to produce a solid fertilizer. In this study, we investigated the suitability of MgO to alkalize and dehydrate urine. We selected MgO due to its low solubility (<2 gL−1) and relatively high saturation pH (9.9 ± 0.2) in urine. Using a laboratory-scale setup, we dehydrated urine added to pure MgO and MgO mixed with co-substrates (biochar, wheat bran, or calcium hydroxide) at a temperature of 50°C. We found that, dehydrating urine added to a mixture of MgO (25% w/w), biochar, and wheat bran resulted in a mass reduction of >90% and N recovery of 80%, and yielded products with high concentrations of macronutrients (7.8% N, 0.7% P and 3.9% K). By modeling the chemical speciation in urine, we also showed that ammonia stripping rather than urea hydrolysis limited the N recovery, since the urine used in our study was partially hydrolyzed. To maximize the recovery of N during alkaline urine dehydration using MgO, we recommend treating fresh/un-hydrolysed urine a temperature <40°C, tailoring the drying substrate to capture NH+4 as struvite, and using co-substrates to limit the molecular diffusion of ammonia. Treating fresh urine by alkaline dehydration requires only 3.6 kg MgO cap−1y−1 and a cost of US$ 1.1 cap−1y−1. Therefore, the use of sparingly soluble alkaline compounds like MgO in urine-diverting sanitation systems holds much promise.

Contact: Prithvi Simha

Global survey of food consumer attitudes towards urine recycling

The findings from our multinational study that surveyed the attitudes of about 3800 people from 16 different countries, are now published in Science of the Total Environment and available here:  https://doi.org/10.1016/j.scitotenv.2020.144438.


– Cross-cultural & country-level factors explanatory of respondent attitudes identified
– Respondents had positive intention overall but were unwilling to pay price premiums
– Social norms and cognitive awareness of urine’s benefits & risks featured strongly
– Building consumer trust via context-specific messaging can improve acceptance

Our main findings are best summarised by this picture below, which shows the strengths of association for factors explaining attitude of food consumers towards human urine as fertiliser. Factors are grouped by demographics, social norms, benefit/risk perception, substances that respondents believed are normally excreted in urine, and environmental outlooks. Dots are proportional and indicate the strength of association (Cramér’s V values); dashes indicate categories that could not be analysed due to insufficient data.

Picture inserted shortly.

Contact: Prithvi Simha