Thanks for the feedback, interesting figures that fall right into what I expected.

However even at a high $7.5 a month (Most people are not willing to pay that much for satellite PayTV subscription here in Uganda, which is probably perceived as a higher value for money) and a relatively low mass-production price of $500, I don't see how a privately operated business would ever see a profit & a return of investment over 10 year's lifetime ($900 rental revenue in total + fertilizer sale VS. $500 unit cost and $500 O&M costs, not even taking capital costs into account).

But I will follow this project in the coming years for sure, as it seems like the most advanced and feasible one of all the ideas that ran under the "reinvent the toilet" label. Who knows, maybe the cost issue will be solved somehow!

Dear Julius

We see the costs of the toilet in the same range as you: we estimated our costs based on mass-production and set the target price of 500 $ per toilet. We expect the membrane for water reuse to make up around 20 % of this price. We are optimizing electrolysis at the moment, as are other RTTC grantees - thank you for your input. We count on 50 $ per year for maintenance of the toilet.

A business model has been set up for the diversion concept. You will find it on our home page: www.diversionsanitation.com. We expect a 5-person family to pay 7.5 US$ per month for the entire service (rent including twice-a-week collection of feces and urine), based on a shared toilet between two families and a life time of the toilet of 10 years (this is the guarantied life time of the membrane). Please note that the system is intended for dense informal settlements (150-350 persons/ha) and not for rural areas.

In an on-going project (which is not part of the RTTC grant), we evaluate the assumptions in the business model – especially also the market value of the fertilizer products. For more information on fertilizer production from urine, please consult the Vuna homepage (www.eawag.ch/vuna). For feces treatment, we rely on the work of the Climate Foundation on pyrolysis (production of energy, which will be used for fertilizer production from urine, and biochar).

The water provision is based on recycling: only about 1-2 Liters of water must be added per day. This water does not have to be clean. The membrane system can provide around 75 Liters of clean water per toilet and day under realistic conditions. We believe that the service of hand washing and wastewater treatment (with recycling and thus no pollution of the urban environment) will increase the hygienic benefits of sanitation in dense slum areas.

We are well aware that the project is ambitious. However, we are convinced that toilets must be attractive in order to succeed. It will of course take years before real mass production of the system can take off; we will only test the first working toilet next month (the project started in July 2011).

We are happy to answer any questions concerning the project 'diversion for safe sanitation'.

Kind regards
Tove

As nice as this toilet is, I have very serious doubts about the financial feasability of it. Are there anywhere some cost calculations?

I have worked on pretty much exactly the same tech that is used for water-reuse as a system for drinkingwater treatment in emergencies and due to the price of the components (quite a large surface area of UF membrane for ultra low pressure applications and the usual corrosion resisitve platinium covered chlorine electrolysis electrodes etc.) it was never considered anywhere near a price point for what people would buy it even with a subscription model.

Just by guessing I would say the final version will cost at least 1000€ each and even in larger scale production I would be very surprised if it would go below 500€ any time soon. But I would love to be shown wrong on this.

Thus given the usual low profitability of sanitation reuse products and the probably low willingness to pay much for rental of the toilet (10€ a month is probably too high already for most people that seem like the target customer), I have my doubts that this will scale up as a business solution.

Well... maybe a version without all that over-engineered water reuse system might be a nice alternative as a flushable UDDT squatting pan for middle class customers.

You can watch Tove Larsen's project presentation at the Second International Conference on Faecal Sludge Management (FSM2) that took place in Durban, South Africa during 29 to 31 October 2012.

Let me give you a more formal introduction to this grant today:

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Title of grant: Diversion for safe sanitation

Subtitle (more descriptive title): Flushable urine-diverting dry toilet with on-site wash water recycling embedded in a concept of transport logistics and treatment

Name of lead organization: Eawag (Switzerland) in cooperation with EOOS (Austria)
Primary contact at lead organization: Tove Larsen
Grantee location: Duebendorf, Switzerland
Developing country where the research is being tested: Uganda in 2013 and 2014

Short description of the project:
The Swiss Federal Institute of Aquatic Science and Technology (Eawag) and industrial design company EOOS develop a urine-diverting dry toilet with the additional feature of an integrated wash water recovery that allows for the comfort of hand washing and toilet cleaning. The squatting “diversion toilet” pan separates three streams: undiluted urine, dry feces and wash water. The used water is treated on-site based on ultrafiltration and recycled for the same purposes. Separated urine and feces are transported to a semi-decentralized recovery plant (scale: ~800-1000 persons) where nutrients and energy are recovered.

Goal(s):
The goal of RTTC Phase 1 (August 2011 – July 2012) was to design a urine-diverting dry toilet, that is user-friendly, attractive, hygienic, and allows for the use of water for personal hygiene and cleaning of the toilet surface and to deliver proof of the recycling technology as well as the proof of transport logistics and treatment concepts.

Goal of RTTC phase 2 (November 2012- February 2014) is to further develop the “diversion toilet” design and the on-site water recovery technology and to finally demonstrate an integrated toilet prototype “in an operational environment” (Technology Readiness Level TRL 7). Furthermore, the treatment technology for urine and the cooperation with external partners for feces treatment will be further developed to be demonstrated “in a relevant environment” (TRL 6). Additionally, a proof of concept will be delivered for a further development of the toilet with on-site feces and urine treatment (= “diversion autarky” toilet) (TRL5). Please note that existing urine treatment technology has been developed in the project VUNA (www.eawag.ch/vuna) and all further developments for the blue diversion project takes place in close cooperation with the VUNA project.

Start and end date: Phase 2: November 2012- February 2014
Funding for this research currently ongoing (yes/no): Bill & Melinda Gates Foundation, Swiss Development Cooperation (for the business model), Eawag and EOOS in-kind funding

Research or implementation partners:
• EOOS, Austria
• Makerere University, Uganda

Links, further readings – results to date:
Project website: www.diversionsanitation.com
Website of EOOS www.eoos.com/cms/?id=250

Video (includes Bill Gates himself talking about the RTTC toilets (this here is Charles Niwagaba):



Paper at the FSM-2 Conference in Oct. 2012:
www.susana.org/en/resources/library/details/1747

How about the costs?
The requirements of the challenge were 0.5 USD/person/day (capital and O&M). We think that we can reach that. Some numbers on this are included in the business model here:
www.eawag.ch/forschung/sww/gruppen/rttc/...on/business/index_EN

I hope you are finding this information useful and am happy to respond to questions (together with my team),

Tove

P.S.
1-minute video about the concept (produced just after the Reinvent the Toilet Fair in Seattle, August 2012):

Dear Elisabeth

You are right about the function of the flush (especially the removal of menstrual blood is essential) and we will see how the idea of a brush is accepted by the users. We are however not going to mix water and urine. Water is treated and reused, while urine is transported un-diluted to a resource recovery plant. We are all working hard at the moment to make this possible: the designers at EOOS to ensure that urine and water are not mixed; we at Eawag to ensure that the on-site water treatment treats the flush and hand wash water to a safe hygienic level.

Regards
Tove


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Note by moderator: The following information was provided by Bernhard in response to Elisabeth's questions above:

As Tove explained water and urine is not going to be mixed.

About 500 ml will get used for the flush. Maybe even 1 l since it depends on how the user wants to use the water. Per toilet visit there is 1.5 l available. The last 500 ml are reserved for hand washing and it is not possible to access them other than through the hand washing tap. But the other liter can either be used for anal cleansing with a hand shower or for flushing - in no specific ratio.

That way we hope to encourage hand washing after the toilet visit.

Why we are so keen on flushing? Well because we feel it just gives a good feeling of cleanliness. Our goal is not plainly to make "a toilet for the poor" but a toilet that we would want to use ourselves. Hopefully such a toilet gets accepted as well as "our" coca cola or cellphones

According the diversion of urine and water; we´ll keep you updated. at the moment we are looking into different approaches. but as you mentioned the precipitations are a problem - that only show up after some time.

Dear Bernhard,

Thanks for sharing - these are very beautiful design sketches!
I am just wondering: why exactly are you so keen to flush the UD pan? Flushing away the urine itself is pretty unnecessary in my view, as it is basically invisible and ocourless. But do you want to flush to get rid of menstrual blood or pubic hair for example? Possible faeces stains would not be removed with such a flush, for that you always need a brush...

And as far as odour is concerned, the flush makes no difference; key is the odour control between the outlet and the urine storage tank (if there is a urine storage tank). The best device here is the EcoSmellStop, I think (= two sheets of a silicon curtain which open when urine passes). What odour control do you envisage for your toilet's urine outlet pipe?

And how do you conceptually deal with the disadvantage of urine flushing, namely that you have more volume of liquid that you need to collect and transport; and a diluted fertiliser. Please remind me how many Litres or Millilitres you are planning to flush with?

Regards,
Elisabeth

Can a dry toilet be flushed? ...or a bit of background info on the pan:
Some of you might have seen our diversion toilet at the Reinvent The Toilet Fair in Seattle last year or on the World Toilet Day at Eawag in Switzerland.
And from the feedback we´ve got, however impossible the idea of flushing a dry pan might sound in the beginning, people do like the idea.

So we thought we might share how it can be done, since that aspect might be easily implemented by others to improve their toilet pan design.

Basically, the pan is a urine diverting pan, but the rim around the feces opening is raised so water can flush around it without getting in the feces chamber.




Wherever water is available this alone is a major improvement to conventional dry toilet pans. Water can be reused from hand washing for example. The water greatly reduces odor from urine and generally adds to the feeling of cleanliness.

At the moment we are working on making this a UDDT-F pan (urine diverting dry toilet FLUSH). So water and urine can be diverted in the pan as well. We keep you updated on our progress in the future.

You are very welcome to use, modify and build upon this design as long as it´s applied in or in the context of developing countries. If you do so, please share with us and the rest of the community in this thread. If, on the other hand, you plan to become a millionaire by selling our idea in the developed countries, talk to us first. The design is protected, patent pending.

Some additional information on the project:
www.diversionsanitation.com

Thank you for the interest in our diversion toilet. More information can be found on our homepage www.diversionsanitation.com.

And here some answers to specific questions:

1. Many treatment methods exist for the recovery of resources from feces and urine and most of them are applicable on the scale of a Resource Recovery Plant as suggested for the diversion toilet. My own contributions to the literature on this topic can be found at the following homepage: www.eawag.ch/about/personen/homepages/larsen/index_EN. For those who have no access to a free library, please address the Eawag library for free copies.

2. We are very happy about the positive response to the toilet interface and we are working hard to develop a prototype. However, the toilet is not yet available. We hope to present the first prototype in December 2013 and will keep the SuSanA forum updated on any substantial progress.

Dear Christoph and Tove,

Larsen (Tove Larsen) is the lead person in the Eawag project to develop a new UDDT interface, which is described in the following link (including photos):

www.eawag.ch/medien/bulletin/20120815/index_EN

This is a beautiful toilet and I think that all of us on the Forum would like to see and use one of these.

Tove, what are the current thoughts on urine and feces treatment?
Where will the new toilet be piloted?

Best wishes,
Chris Canaday

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Note by moderator (EvM):
See also Tove Larsen's paper about this concept at the FSM Conference here (it is number 23 in the list):
susana.org/lang-en/library?view=ccbktypeitem&type=2&id=1624

Dear Christoph,

You are very observant. The reason why her post, as well as 164 others, are only visible now, is because they were originally made on the closed Gates Foundation "Sanitation Network", and as of yesterday, they are now open to the public. This is part of the Gates Foundation funded project of joining their sanitation grantee community with the SuSanA community and the wider sanitation community. (the background to this move is explained here: forum.susana.org/forum/categories/97-oth...nda-gates-foundation).

So if you are up for some interesting reading on what was discussed there in that closed discussion forum (which was called Sanitation Network) during the last year and a half, please read here on the forum and comment on the threads which we grouped in 5 sub-categories here:
forum.susana.org/forum/categories/96-inn...-technology-exchange

Note to those who had posted in the Sanitation Network: we have checked each post carefully for its suitability and only moved those that are of relevance to this wider forum. (any e-mail addresses inside of posts were removed to protect privacy). If you have any concerns at all, please e-mail me at the address below.

Merry Christmas to all who celebrate it!
Greetings from Rabat in Marocco (no Christmas here),

Elisabeth

Dear Larsen,

for some reason your post appeared (to me) only now, even though you made it apparently in August.
The technology you described seems to be very interesting. Could you share some fotos? Or a link to more information? Thanks.

Christoph