Hi Eva：
I have been studying the subject very carefully. 
It is probably a good choice to use it as the public toilets in our big cities and villages.
We are working with some parties to design public toilets for Shen Zhen  with a population of  30 million people. The road is very wide and the metro is very modern without enough toilets. It is very embarrassing for me to take the metro sometime.
The blue diversion Autarky looks very nice and compact. My question is how you deal with the bad smell while the solid waste is being burnt.
FIY. I remember that the product was exhibited in 2008 Toilet Summit in Macao
It is a good timing to market the subject in China.
Please contact me for the  possible business opportunities in China.
best wishes
Scott
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Hi Chris,

without knowing more of your house and concept I would suggest a solar water pump (12 V) without any battery. If the tank on the second floor ist big enough the pump might work during the sunshine and remain lazy the other times... Watch out for the pressure needed.... Investment should be less than 50 Dollars.

Good luck,

Heiner

Dear Eva,

Thanks for getting back to me. Sorry for my delay this time, as I had not seen your reply.

Here is my attachment on Suggestions for Sustainable Sanitation again:
 

I would like to remind you that solar panels are not inexpensive or eternal. In any case, it would need a battery to keep running at night and this battery could be charged by a bicycle or something.

When designing a Urine-diverting Flush Toilet, I would suggest that testing be done to see how well it works. Among other things, a Go-Pro camera could be stuck to the dorsal inside wall of the toilet and persons of both sexes could sit down and pee, to see if all of the urine goes where it is supposed to. (Any body parts in the video could be quickly edited out, plus the camera could be aimed very low.) It is also easy to see how much flush water goes down the urine duct. Thirdly, the fecal wastewater could be tested for things that should only be in the urine (urea?).

For our Closed-loop Flushwater Recycling, I had been planning to use anaerobic digestion in an Anaerobic Baffled Reactor (ABR), although I am now considering a Vermifilter, in both cases with polishing being done by a Vegetated Sand Filter (artificial wetland) on the roof, which is also the tank supplying the toilets. I have this VSB half-built, but, for some reason, the water pressure is not strong enough to fill the toilet tanks on the second floor, only on the ground floor. Does anyone know how to fix this? Does anyone know how to pump this recycled water up to the roof with the power of rain going down a downspout?

Best wishes,
Chris

Dear Chris,

My apologies for the late reply.

The squatting toilet from the Blue Diversion Project and the toilet prototype we tested in South Africa are complementary. In the Blue Diversion Toilet, urine and feces were collected in the toilet, with the aim to collect them and treat them at a semi-decentralized scale (e.g., at a neighbourhood level). The wash and handwashing water was recycled in the system. We would still see such a collection system as an adequate solution for densely populated areas.

The new toilet prototype aims at treating all waste streams (water, urine and feces) on site. As the feces treatment module was not ready for field-testing, we collected and discharged the feces during the toilet field test. This is certainly not our long-term goal, and our colleagues at the Paul Scherrer Institute are continuing research on an efficient feces treatment technology (more information on our project website www.autarky.ch).

You suggest the use of exercise equipment to reduce the need for electricity. I am afraid this will not work, as the system needs constant power, for instance for the aeration of the biological wastewater treatment tank or for the production of chlorine for disinfection. What we have done, though, to reduce the dependence on the electricity grid is to operate the urine treatment module with solar power and a handwashing station with solar power and backup energy from a fuel cell.

We have not done a detailed analysis of the urine and feces separation.
You can find a study of the Aquatron here: Vinnerås,B., & Jönsson, H. (2002). Faecal separation for nutrient
management––evaluation of different separation techniques. Urban water, 4(4),321-329. 
and all information on the save! toilet here: news.laufen.com/wp-content/uploads/2019/...ve_EN_RZ_FINAL-1.pdf

It is exciting to hear that you are getting closer to achieving closed-loop flushwater recycling in your own house - may I ask which treatment steps you are using?

Best regards,
Eva

PS: Unfortunately, I could not find the attachments you mentioned?

Dear Eva, 

Thanks for letting us know about the advances of this important Project. 

I was surprised to see that this was not about the Blue Diversion Toilet that is one integrated unit for squatting, which we have previously discussed on this Forum. Has that model been discontinued? 

I congratulate you greatly on this important work, but would like to suggest the goal of it being entirely OFF-GRID, with no need for electricity or sewers.

I was very disappointed to see that the project is dumping feces into the sewer, since I would suggest that one of the goals should be to avoid exactly that, even during any pilot stage, since we all know about the high cost, limitations
and scarcity of sewage treatment in the world. Why not just bury the feces in a hole in the ground and maybe plant a tree on top of them? 

About the electricity, it would be excellent if the users could operate it via something similar to exercise equipment (e.g., treadle pumps, etc.), which could pump the water and generate the electricity needed for the treatment. Since it is not a large volume of water, it may also be feasible to pump it via wind power or with the weight of rainwater going down drainpipes from roofs. 

About the urine, if units are in peri-urban or rural locations, I would suggest simply dispersing the urine in perforated hoses buried 10 cm below the surface of the soil among fruit trees and banana plants, especially since you are spending as much electricity on treating the urine as in treating the flush water for recycling. In densely populated urban areas, hoses could be established as “peepee pipelines” to drain urine by gravity to farmland downhill. 

Have you determined the percentages of separation in the beautiful EOOS/LaufenSave! Toilet?
What % of urine is kept separate? With what % of flush water mixed into the urine?
What % of feces are separated by the Aquatron? What % of flush water goes with them?
What % of flush water is recovered for recycling? 

I am gradually working toward achieving Closed-loop Flushwater Recycling in our new house, which was built with entirely separate piping for greywater and blackwater ... and separate pipes for providing water to the toilets. (Does anyone know how to get toilets to work with only the water pressure of a tank on the roof?)

I attach again some Suggestions for Sustainable Sanitation, which include various types of water recycling. 

Best wishes,
Chris

Dear all,

Our new open access publication on our field testing experiences is out:

Sutherland, Reynaert, et al. (2020). Socio-technical analysis of a sanitation innovation in a peri-urban household in Durban, South Africa. Science of The Total Environment, 143284. doi.org/10.1016/j.scitotenv.2020.143284

The adoption of new sanitation technologies does not depend on technical functionality alone. Lack of social acceptance is a frequent cause for so-called “failed technologies”. However, the socio-cultural meaning and use of toilets receives less attention than the technical design and functionality of innovative sanitation systems. This is why we studied the socio-technical relationships formed when field-testing the Blue Diversion Autarky Toilet in a 14-people peri-urban household in Durban, South Africa. A transdisciplinary research process, which emerged through the assessment, enabled the integration of different forms of knowledge from multiple actors to address the complexity of problems related to the development of socially just sanitation. The benefit of engaging with societal actors in sanitation innovation and assessing its outcomes using both the technical and social sciences is evident in this paper.

I wish you a good read and am happy to answer any questions you may have,
Eva

We have published field testing results for our water recycling system!The publication is open access and can be read or downloaded here: doi.org/10.1016/j.wroa.2020.100051

In three field tests in Switzerland and South Africa, we produced sufficient quantities of safe and appealing water for handwashing or toilet flushing. The treated water was readily used in all testing
contexts. We did, however, experience some technical difficulties, as we
had tried to use low-costs components when building the system.
Especially the final disinfection with electrolysis was prone to failure, with
the electrolysis recirculation pump breaking down in all trials. For a larger-scale implementation of small-scale water reuse system, we see a need for online monitoring of parameters related to health risks.

Please feel free to contact me if you have questions about the publication or, more generally, about our water recycling system.
Eva

Dear Elisabeth,

Thank you very much for your feedback and questions.

We are currently in contact with private companies that seem interested in industrializing our technologies.

The costs of our systems will very much depend on the number of units produced. The water and urine treatment systems should not cost more than a few hundred USD when produced in large numbers, and could be retrofitted to existing toilet superstructures. Most components we use for the urine and water treatment are already commercially available on the market. With good funding schemes, we still hope to see our systems in places where they are most needed, including slums.

You also asked about maintenance. This may indeed be the largest challenge to our systems. Especially for the urine treatment, a regular service to collect the produced fertilizer is necessary - but the fertilizer collection is also linked to a revenue, which could make this service an interesting business opportunity. For the water treatment, we are working on the selection of sensors that could give us online information on the water quality, and thus allow for immediate intervention in case of maintenance requirements.

We were, however, astonished to receive attention from industry sectors that we had not anticipated. For instance, train toilet producers have shown interest in all three technologies, as these could significantly reduce the frequency (and thus cost) of emptying the wastewater tanks. The concerns related to costs and maintenance would be reduced in such a setting. Cooperating with such partners might thus be be a practicable way to offer sanitation to a large number of people.

But I agree with your evaluation: it is still a long way from technology development to the marketing of an industrialized product.

I hope I could answer your questions - if not, please let me know.
Eva

Dear Eva,
Thanks a lot for this detailed update! What do you think is the most likely future application case for your technology? You tested it in peri-urban zones of Durban but I can't imagine that it would be economically viable there. Probably far too expensive? Also who would be in charge of maintenance...

It's certainly interesting to see how things have developed from the VUNA project which started ages ago (it went from 2010 to 2015, see here, www.susana.org/en/knowledge-hub/projects/database/details/108) to Blue Diversion and then to Autarky and then perhaps another project after that... It goes to show one has to be patient with the development of these technologies...

Regards,
Elisabeth

Dear readers,

Much has happened since our last post on the SuSanA forum and it is high time for an update on the Blue Diversion Autarky Project. Blue Diversion Autarky aims at developing sanitation systems which provide hygiene and comfort without relying on water and wastewater infrastructure. The project is funded by the Bill & Melinda Gates Foundation (grant number OPP1176460) as part of the reinvent the toilet challenge. In the last project phase, we have developed reactors that treat source-separated urine, water and feces. During the past two years, we have been busy redesigning, optimizing and finally testing these reactors in real-life applications in Switzerland and South Africa.

The photographs below show our test toilet in a peri-urban zone of Durban, South Africa (left: Autarky toilet behind an existing urine-diverting dry toilet, right: inside the toilet cabin, with the urinal in front and the hand washing facility in the back).



Urine treatment
Urine contains nitrogen, phosphorus, potassium and various micronutrients. With the right treatment, we can produce a urine-derived fertilizer that can be used in agriculture. Two processes are used in our system to treat the source-separated urine in the toilet: urine stabilization and water removal. Urine stabilization with calcium hydroxide prevents the formation of ammonia from urine (and thus the smell) and kills the pathogens. However, the high water content of urine – no matter if stabilized or not – requires significant storage capacity and can make the collection and transport to the agricultural fields very costly. Volume reduction through forced convection does not only reduce costs for storage and transport, but could also facilitate field application of the concentrated fertilizer.
We field-tested the urine treatment module in two applications: as part of a toilet system in South Africa (left picture, harvest of the fertilizer) and in a tiny-house application in Switzerland (right picture).



The capacity of the urine treatment reactor was sufficient in both field tests. The system proved to be robust and operational in the field. The stabilization process worked well and there was no smell during the operation. We are currently working on a more detailed mass balance of the whole sysem with complementary laboratory-tests. We are planning to publish the results once we have collected all the necessary data.

Water treatment
The water treatment system, referred to as Water Wall, recycles hand washing water, toilet flush water (separated from the major part of urine and feces), or both. A multi-barrier approach with four treatment stages (bioreactor, ultrafiltration membrane, activated carbon filter and electrolysis) ensures that the water is safe for reuse. Water treatment prototypes were extensively tested under laboratory-conditions, under which they reliably removed pathogens, nutrients, malodor, and color from recycled water. However, when moving outside the laboratory, we expect a much higher variability of the number of users, composition of the water and external conditions. This is why we exposed different configurations of the Water Wall to real-life conditions.
We field-tested the Water Wall in three applications: as part of a toilet system (left picture) and as part of a hand washing station (right picture) in South Africa, and as part of a hand washing station in Switzerland.



In all three field tests, we produced sufficient quantities of safe and appealing water. The treated water was readily used in all testing contexts. We did, however, experience some technical difficulties, as we had tried to use low-costs components when building the system. Especially the electrolysis post-treatment was prone to failure, with the electrolysis recirculation pump breaking down in all trials. We are currently preparing a manuscript on the field test and will post an update on the forum once it is published.

Feces treatment
The process used to treat the feces is called “hydrothermal oxidation” or HTO. When mixed with air and heated above around 400°C under high pressure, the fecal sludge decomposes and is oxidized completely to carbon dioxide and water. Ideally, the process is autothermal, meaning that the oxidation of the feces releases enough heat to maintain the high temperature. In the current project phase, we have been developing a comprehensive computer model of the reactor to improve understanding of the HTO process. We also improved the third prototype generation of the so-called FOX reactor (short for feces oxidation) and tested it with real users at Eawag (picture below).



The field test at Eawag was successful. The amount of processed feces was satisfactory, only the total solids content of the sludge was below expectations, making autothermal operation impossible. In accordance with previous laboratory-experiments, the proportion of organic solids in the treated product was significantly lower than in the sludge, so the desired oxidation of the fecal sludge was achieved. From the various technical problems that have arisen, we were capable to detect critical components and already implemented most necessary changes.

Research or implementation partners:
- Eawag (Swiss Federal Institute of Aquatic Science and Technology)
- PSI (Paul Scherrer Institute)
- FHNW (University of Applied Sciences and Arts Northwestern Switzerland)
- EOOS (Austrian Design Office)

Links, further readings:
Project website: www.autarky.ch

Related projects:
- www.bluediversiontoilet.com , the Autarky project is building on the results from the Blue Diversion project, especially regarding the water treatment.
- www.vuna.ch, the VUNA experience gives great insights about urine treatment and inspiration for the Autarky urine module.

Publications (since 2015):

• Mangold, F.; Pilz, St.; Bjelić, S.; Vogel, F. (2019). Equation of state and thermodynamic properties for mixtures of H₂O, O₂, N₂, and CO₂ from ambient up to 1000 K and 280 MPa. The Journal of Supercritical Fluids, 153: 104476, doi:10.1016/j.supflu.2019.02.016


• Ziemba, C.; Larivé, O.; Deck, S.; Huisman T.; Morgenroth, E. (2019). Comparing the anti-bacterial performance of chlorination and electrolysis post-treatments in a hand washing water recycling system. Water Research X, 2: 100020, doi:10.1016/j.wroa.2018.100020


• Ziemba, C.; Larivé, O.; Reynaert, E.; Morgenroth, E. (2018) Chemical composition, nutrient-balancing and biological treatment of hand washing greywater, Water Research, 144: 752-762, doi:10.1016/j.watres.2018.07.005


• Decrey, L.; Kohn, T. (2017) Virus inactivation in stored human urine, sludge and animal manure under typical conditions of storage or mesophilic anaerobic digestion. Environmental Science: Water Research & Technology, 3(3): 492-501


• Nguyen, M. T.; Allemann, L.; Ziemba, C.; Larivé, O.; Morgenroth, E.; Julian, T. R. (2017) Controlling bacterial pathogens in water for reuse: treatment technologies for water recirculation in the Blue Diversion Autarky Toilet, Frontiers in Environmental Science, 5, 90 (13 pp.), doi:10.3389/fenvs.2017.00090


• Hübner, T.; Roth, M.; Vogel, F. (2016) Hydrothermal oxidation of fecal sludge: experimental investigations and kinetic modeling, Ind. Eng. Chem. Res. 55 (46): 11910-11922


• Randall, D. G.; Krähenbühl, M.; Köpping, I.; Larsen, T. A.; Udert, K. M. (2016) A novel approach for stabilizing fresh urine by calcium hydroxide addition, Water Research, 95: 361-369, doi:10.1016/j.watres.2016.03.007


• Künzle, R.; Pronk, W.; Morgenroth, E.; Larsen, T. A. (2015) An energy-efficient membrane bioreactor for on-site treatment and recovery of wastewater, Journal of Water Sanitation and Hygiene for Development, 5(3): 448-455, doi:10.2166/washdev.2015.116


• Larsen, T. A.; Gebauer, H.; Gründl, H.; Künzle, R.; Lüthi, C.; Messmer, U.; Morgenroth, E.; Niwagaba, C. B.; Ranner, B. (2015) Blue Diversion: a new approach to sanitation in informal settlements. Journal of Water, Sanitation and Hygiene for Development, 05(1): 64-71, doi: 10.2166/washdev.2014.115


• Ravndal, K. T.; Künzle, R.; Derlon, N.; Morgenroth, E. (2015) On-site treatment of used wash-water using biologically activated membrane bioreactors operated at different solids retention times, Journal of Water Sanitation and Hygiene for Development, 5(4): 544-552, doi:10.2166/washdev.2015.174

Video of the Autarky toilet:

Outlook
Our project is running until May 2020. We are currently working on the compilation and analysis of our field-testing results to make them publicly available. On the longer term, we would like to see the technologies move forward towards a larger-scale implementation of prototypes under the lead of an entity that would be specialized in the detailed engineering, construction and marketing of such systems.

If you want more detailed information, please do not hesitate to contact us. We are happy to answer your questions.
Eva

---

Eva Reynaert
Eawag (The Swiss Federal Institute of Aquatic Science and Technology)
Process Engineering
www.autarky.ch

Hi Chris

thank you very much for your critical comments, we really welcome them.

It is true that the Autarky toilet requires constant electricity, but this energy demand will be covered by a solar panel. To switch the toilet on or respectively heating up the feces module, a generator or a plug is needed once. The installation of the toilet must be done by trained stuff which involves the provision of a generator for this first heating up. We consider it more complicated to get energy from outside as you proposed.

Regarding your doubts on the feces treatment, we think it would be a very big step if we could treat feces on household scale and a tremendous cost reduction from an environmental and social point of view. The reactor concept consists of materials which are available in almost all parts of the world and not of high-tech nature, we always have the cost argument in mind (it is difficult but we really do).

We will develop a modular toilet where urine, water and feces should be treated independently but in one toilet system and thereby being able to respond to different demands and conditions. It might be an option that urine is distributed to the soil in less populated areas, however it is not the safest way and in this project we have the goal to develop a toilet especially for the urban context where no space is available to do so.


I hope I could answer your questions - if not, please let me know.
Thanks a lot for your comments,
Stefanie

Hi Steffi,

Thank you for this info. I am disappointed that this model constantly requires electricity, as this limits its decentralized application. And what happens when there are blackouts?

I suggest it may be worthwhile to explore the possibility of getting energy from exercise or playground equipment on the outside of the toilet.

This new model takes on the huge challenge of processing all of the excrement on-site, but this seems to be with expensive, high-tech equipment that may be prone to failure and more complicated to maintain. (And the more expensive it is, the more likely it may be stolen to sell intact or in its component parts.)

I suggest that you offer the option of simply distributing the urine in the soil among fruit trees or urban agriculture, via a perforated hose buried below the surface (in places where there is enough room). Also, in places that are not so water-stressed, new water could be piped in and then also be dispersed in the soil.

In general, I think it would be good to keep various options open in order to adapt to different conditions, remembering that not everyone who needs a toilet is in the inner city (with electricity).

In any case, it will be spectacular if you achieve reliable, economical on-site treatment of the feces, in such a small space, since the feces are obviouosly the most dangerous portion of the excrement.

I look forward to seeing more details and news from your project.

Best wishes,
Chris Canaday