Blog from the Environmental Engineering Research Group at SLU
Next week, Annika Nordin and Cecilia Lalander, Researchers at Kretsloppsteknik will be at the Uppsala City Library to discuss why our current water-borne sanitation system is not as good as many might think. They will present what we believe will be the future sanitation solutions, which in a better and more efficient way safeguard and manage the resources in our sewers.
Within the MORTTI project, our group’s urine drying technology is being piloted at Pori Brigade’s military training site in Finland. Earlier this week, as part of an organised media day event, members of our group Caroline Karlsson and Prithvi Simha alongwith MORTTI project partners interacted with several local and national media outlets. Click below to read what the media thought of this visit and our toilet system.
YLE: On TV The soldier’s piss improves the world – dry urine is a good fertilizer & In Print https://yle.fi/uutiset/3-10730337
Maaseudun Tulevaisuus: The Defense Forces are trying to recover urine as fertilizer – In the Pori Brigade exercise area there is a Biomaja field toilet
Helsingin Sanomat: In SÀkylÀ, the nutrients of the urine are preserved, with the aim of making urine fertilizer
Satakunnan Kansa: Converting soldiers’ urine into dry fertilizer powder – a Swedish invention that can come into play at festivals in the future
Verkkouutiset: The recycling of the officers’ urine is being tested
LÀnsi-Suomi: Army is testing a pilot toilet in SÀkylÀ
Contact: Prithvi Simha
On the 8th of April, the MORTTI project partners organised a media day for our project in Finland that has been operational since the first week of March. This 3-month pilot stabilises and dries human urine collected from soldiers, to be safely recycled as a dry powder fertiliser. The project pilots the urine drying technology developed by our research group at SLU. Representing Kretsloppsteknik at this event were Caroline Karlsson and Prithvi Simha.
Proposed Title: Identifying effective transport systems and logistics for new sanitation systems that produce fertilisers from human wastes.
Credits:Â 30 credits; Level:Â Advanced
Subject:Â Technology or Environmental Science
Start: As soon as possible
Background: In the sanitation sector, there is growing recognition that we urgently need to change the way we handle, treat, and recycle human wastes in our environment. At the Swedish University of Agricultural Sciences (SLU), the environmental engineering research group has developed the âurine dehydratorâ, an exciting new technology that converts liquid human urine into a hygienic, commercial-quality, dry fertiliser. The technology involves two steps, (a) using a urine-diverting toilet at home, to separately collect urine without the faeces; and (b) drying the urine within an alkaline substrate that placed is placed in the urine dehydrator.
We are looking for a motivated and enthusiastic student to assist in developing a computer model that simulates the impacts of different technology choices for management of wastewater flows. The model will be incorporated into a serious game that we are developing to guide sanitation planners and decision-makers. The game is a multi-stakeholder, spatial planning game for municipal sanitation which focuses on resource recovery. It will allow for a visual representation of what technologies can be used and what resources can be recovered from sanitation facilities.
After a week in the city of Tampere in Finland, our team over there finished integrating a urine drying bed into the Biomaja toilet. The entire toilet is on a trailer, making it portable and houses a dry urinal and a urine diverting dry toilet. The urine treatment is done by alkaline dehydration, a technology developed by our research group and which we have been pursuing for several years now. The urine treatment unit requires an area of just 0.75 m2 and has a capacity of processing 30 L urine/day into a dry, nutrient-rich fertiliser.
On the 4th of March, members of our group that travelled to Finland, along with partners from the MORTTI project transported the integrated toilet 100 km west of Tampere. The toilet is now very much operational, and is intended to be used for a period of at least 3 months.
In a new paper published in Water Research, Senecal et al. assessed what hygienic health risks may occur when human urine is dehydrated. The experiment was set up to simulate that the last person using the toilet (before the dehydration medium is changed) is contaminating the medium with misplaced faeces, with no time for dehydration of the urine, i.e. a worst-case scenario. It was found that urine dehydration in itself achieved a concentration < 1 A. suum per 4 g of dehydrated medium which fulfils the WHO guidelines for unrestricted use.
Decentralised sanitation technologies based on source separation of toilet waste have attracted a lot of research attention – the social sustainability of these technologies, not so much. To attempt to fill this gap, members of the Kretsloppsteknik group collaborated with researchers at VIT University, to explore what food consumers in India think of urine recycling. The results were recently published in the journal Water Research, where a survey of 1252 consumers at the VIT University campus revealed: 68% stated human urine should not be disposed but recycled, 55% considered it as fertiliser, but only 44% would consume food grown using it. 
In a recent study published in Water Research, members of the Kretsloppsteknik group investigated the possibility of alkalising human urine by anion-exchange and dehydrating urine into a dry fertiliser powder.
Fresh urine was passed through an ion-exchanger, stabilised by alkalisation (pH >10), added to an alkaline media (wood ash/alkalised biochar) and dehydrated
Simha, P., Senecal, J., Nordin, A., Lalander, C., VinnerĂ„s, B., 2018. Alkaline dehydration of anionâexchanged human urine: Volume reduction, nutrient recovery and process optimisation, Water Research. In Press. doi: 10.1016/j.watres.2018.06.001.
The saying âwe are what we eatâ is only part of the story. What we eat is what we excrete, and this means plant nutrients. Human excreta contain the same nitrogen, phosphorus and potassium (N-P-K) as the fertilisers used to produce the food consumed (Winker et al., 2009). However, human excreta are considered unwanted waste throughout the world, creating humanitarian and environmental problems (Baum et al., 2013). In order to replace the nutrients removed from the fields during harvesting, more fertilisers are manufactured in industrial processes that are contributing to environmental changes at global level (Rockström et al., 2009). Recycling human excreta back to agricultural fields would reduce the current dependence on fossil fuel-derived fertilisers (RamĂrez & Worrell, 2006). It would also improve crop yields in e.g. sub-Saharan Africa, where fertiliser application is low (FAO, 2015), and protect marine ecosystems in the Baltic Sea by limiting the flow of excess nutrients to surface waters (Rockström et al., 2009).