Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) – currently testing the blue diversion toilet in urban slums
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Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 09 Aug 2012 12:41 #2956

  • larsen
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We developed a dry source-separating toilet with on-site ultrafiltration water recovery for wash and “flush” water increasing user comfort and cleanliness of the toilet. The toilet features an innovated dry source separating squatting pan which can be cleaned with water from the on-site water recovery. By foot activation, the squatting pan transforms by rotation of 90 degrees into a washing pan.

In the back wall of the toilet the compact water recovery technology is contained. While feces and urine are collected under the separation pan, the soiled water from hand-washing, pan flushing, anal cleansing and menstrual hygiene is fully recycled on-site.

The toilet is designed for the set up in informal settlements, each toilet shared by two families. As a (re)movable piece of furniture it can be retrofitted into existing toilet superstructures, or in any other bathroom and allows for setting up a “Rent a Toilet” system. Treatment of the separated feces and urine does not take place on-site, but in a semi-decentralized Resource Recovery Plant (RRP), recovering the waste of 800 -900 toilet users. Source-separation and the economy of scales in the RRP are main reasons that we are able to meet the RTTC goal of $0.05 per person and day. The toilets are connected to an RRP via a logistic concept, which is part of a sanitation business, which also runs the RRPs and rents out the toilets.

So far, we focused on the toilet design and the technology development of the on-site water recovery. Moreover we delivered a proof of concept for transport logistics and developed a viable sanitation business model. We worked only conceptually on the treatment technology of the RRP. There are various numbers of recovering technologies for separated urine and feces. For urine treatment, we suggest nitrification followed by distillation, because this process is available at RRP scale on a TRL of 5 (developed within the BMGF-financed project Vuna). For feces, the best technology still needs to be chosen. Since many of you have been developing innovative feces treatment technologies, we are confident that one or more of those are suitable at RRP scale.

We look very much forward to an inspiring meeting in Seattle. See you!
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)

Re: We have a new name: diversion for safe sanitation 21 Dec 2012 11:30 #2996

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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

Re: We have a new name: diversion for safe sanitation 21 Dec 2012 11:40 #2997

  • muench
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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
Dr. Elisabeth von Muench
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Last Edit: 21 Dec 2012 11:42 by muench.
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Re: We have a new name: diversion for safe sanitation 22 Dec 2012 12:31 #3007

  • canaday
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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

++++++++
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=ccbktype...p;type=2&id=1624
Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com
Last Edit: 22 Dec 2012 18:03 by muench.

Re: We have a new name: diversion for safe sanitation 07 Jan 2013 10:55 #3052

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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.
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)

Can a dry toilet be flushed? 15 Feb 2013 23:50 #3508

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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.

EOOS_diversion.png

EOOS_flush.png


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
Last Edit: 18 Feb 2013 19:49 by bernhard.
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Re: Can a dry toilet be flushed? 24 Feb 2013 23:05 #3554

  • muench
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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
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Re: Can a dry toilet be flushed? 27 Feb 2013 16:09 #3649

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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


++++++
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.
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)
Last Edit: 13 Dec 2013 11:31 by muench.

Diversion for safe sanitation 02 Mar 2013 19:58 #3692

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

++++++++++

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/docs_ccbk/susana_download/2-1624-larsen-t.pdf

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):
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)
Last Edit: 27 May 2013 07:25 by larsen.
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Re: Diversion for safe sanitation 18 Mar 2013 16:07 #3923

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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.
Ulrike Messmer
Project Officer "Reinvent the Toilet Challenge"
Eawag- Swiss Federal Institute of Aquatic Science & Technology
Sandec - Department of Water & Sanitation in Developing Countries
Dübendorf, Switzerland
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Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 18 Mar 2013 20:04 #3925

  • JKMakowka
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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.
Krischan Makowka
“You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete” - Buckminster Fuller
Last Edit: 18 Mar 2013 20:09 by JKMakowka.

Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 21 Mar 2013 10:03 #3968

  • larsen
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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
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)
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Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 21 Mar 2013 10:58 #3969

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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!
Krischan Makowka
“You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete” - Buckminster Fuller
Last Edit: 21 Mar 2013 11:00 by JKMakowka.

Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 14 May 2013 22:02 #4396

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We are happy to announce that we brought our toilet prototype to Uganda, Africa for user testing.
The feedback we got so far is very positive but we also learned some valuable lessons that will help us to further improve the design.

IMG_3087_transportMedium.JPG
Last Edit: 16 May 2013 09:45 by bernhard. Reason: not funny
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Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 20 May 2013 02:20 #4428

  • gitum
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Dear Bernhard and Tove,

it is very interesting and impressive to see the technologies like ultrafiltration and electrolysis applied in such a feasible and a practical way.

Before reading the comments and watching the videos, the first question came to my mind was how you were dealing with the fouling problem of ultrafiltration membrane. I assume it is a dead end filtration and hence it would be fouled in a short time. It really impressed me to hear that your system has minimum 10 years life time.

I know the focus of the project is user interface but I still want to ask which processes are used to produce fertilizer? I saw you applied cost analysis and I accept you applied it according to the selected treatment options and their end-products. Do you apply only urine as fertilizer or do you also benefit from faeces? I saw in the previous comments that you were considering different treatment options for faeces and I wonder which one have you came up with? It would be also great to hear whether you apply a process to urine or not.

Thank you very much in advance.

Regards,

Gökce

+++++++++++++
Note by moderator (EvM): I just came across this nice 1-minute video clip about the project; it is a bit old (from August 2012), but so professionally done that I thought it should be shared:
1-minute video about the concept (produced just after the Reinvent the Toilet Fair in Seattle, August 2012):

M.Sc. Gökce Iyicil
Research Assistant
Technical University of Munich
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www.tum-ias.de
www.sww.bv.tum.de
Last Edit: 20 May 2013 21:12 by muench.

Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 21 May 2013 10:38 #4446

  • larsen
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Dear Gökce,

thank you very much for your nice remarks on our project. I am afraid that we have not had time to update our homepage on the urine treatment methods, which we are working on in the RTTC project. However, they are derived from the main Vuna process: Stabilization of urine followed by evaporation of water (www.eawag.ch/vuna). We stabilize with partial nitrification and use the RTTC as an opportunity to work on a reduction of the size of the nitrification reactor. The Vuna evaporation is a classical distillation with energy recovery. In a combined RTTC-Vuna effort, we work on heat-driven evaporation in order to become less dependent on electricity. For feces treatment, we rely on other RTTC groups working on different pyrolysis and combustion methods. We will use the heat generated in these processes for evaporating the urine. The results of the work will be presented in March 2014.

Kind regards
Tove
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)

Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 23 May 2013 20:19 #4481

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Dear Tove,

thank you very much for the further information. I am looking forward to follow the upcoming news from March 2014.

Best Regards,

Gökce
M.Sc. Gökce Iyicil
Research Assistant
Technical University of Munich
e-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
www.tum-ias.de
www.sww.bv.tum.de

Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 24 May 2013 06:24 #4483

  • JKMakowka
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gitum wrote:

Before reading the comments and watching the videos, the first question came to my mind was how you were dealing with the fouling problem of ultrafiltration membrane. I assume it is a dead end filtration and hence it would be fouled in a short time. It really impressed me to hear that your system has minimum 10 years life time.


I have by now seen the system here in Uganda, and as expected it is based on this technology:
www.eawag.ch/forschung/eng/gruppen/gdm/index_EN
(with an added aeration pump and electric oxidation as polishing post treatment).

Personally I think such an advanced system should be better used to treat drinking water (here in Uganda), than recycling small amounts of wash water that is abundantly available anyways... but that is another discussion
Krischan Makowka
“You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete” - Buckminster Fuller
Last Edit: 24 May 2013 06:26 by JKMakowka.
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Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 24 May 2013 07:18 #4484

  • larsen
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It was nice that you could visit our first field tests in Uganda!

I agree that Gravity Driven Membrane (GDM) filtration is an excellent technology for drinking water production. I very much hope that this technology will soon come to maturity and become wide-spread - my colleagues are working hard on this. What we try to do with the blue diversion technology is to solve the problem of sanitation in a comprehensive way. We are not only providing clean water for personal hygiene (hand washing and anal cleansing); we are also treating the higly contaminated wastewater, which arises from these activities. We can do this without much energy because urine, feces and water are not mixed in the system. Furthermore, we hope that our system promotes actual hand washing (and not only the theoretical possibility) by offering clean water directly on-site. I do agree that the system is too complex at the moment. What we are testing now is whether people like the services from blue diversion. If we obtain the necessary funding, we hope to be able to start the technology-simnplifying process in June this year.
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)
Last Edit: 24 May 2013 07:19 by larsen.
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Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 27 Jun 2013 09:13 #4871

  • muench
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Dear Bernhard, Tove and team,

You will be pleased to know that your toilet featured on the news in the US yesterday! It has such an attractive design, I think this makes it easier for journalists to pick up on it...

The title of the article is "Gates Foundation offers locals opportunity to learn", and it comes with a nice 4 minute video which includes your toilet:

www.king5.com/news/cities/seattle/Gates-...learn-213190711.html

The kids are out of school for the summer and many parents are looking for ways to keep them occupied. The Bill and Melinda Gates Foundation Visitor Center gives families an opportunity to learn what people around the world face on a daily basis.

"Whatever the conditions of people's lives, wherever they live, however they live, they share the same hopes, the same dreams as you and I," Melinda Gates said.

Millions around the world do not have access to clean drinking water and billions do not have safe sanitation facilities.


I saw it on Twitter (@gatespoverty).
It's always a good thing to get this topic (sanitation) into the mainstream news to raise awareness.

Regards,
Elisabeth
Dr. Elisabeth von Muench
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Frankfurt, Germany
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Re: Sanitation Experts Webinar Stockholm Environment Institute Sept 12 2013 16 Sep 2013 09:23 #5651

  • larsen
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Note by moderator (EvM): Tove's post was moved into this thread to stay with the other posts about this project. The questions that Chris Canaday had asked to Tove, as a result of watching the recording of the expert chat, are here:
forum.susana.org/forum/categories/139-ge...te-sept-12-2013#5637



Hi Chris

Thanks for your questions, which are all very relevant. I will answer them as well as I can. The technical problems with people talking at the same time is an artefact from processing of the tapes. I hope it will be corrected soon. In reality, we were all very disciplined!

1) First of all: The feces container will not look like this. It is a simple model showing the principle we are aiming for. We are aware of all the aspects, you are mentioning and trying to find solutions (reduce visibility of feces; make the container large enough without increasing the size of the toilet; give feedback when the container is full). The container will be designed for containing around 4-5 days of feces from 10 people, i.e. roughly 16 kg of feces (+ toilet paper). We plan for an emptying service twice a week, meaning that the container will normally not be full and thus less heavy.

2) We do have biological treatment in the water wall. The water, which will be chlorinated in the electrolysis process has already been biologically treated and ultrafiltrated. Chlorination is meant as the last disinfection step similar to what is done in water distribution networks in order to prevent re-growth of pathogens. We do not expect recycling to increase the risk of resistence, because the microorganisms will not pass the ultrafiltration unit. The critical issue is biofilms and we will keep an eye on them.

3) We chose a principle of water recycling in order to set up a system, which has a good chance of providing hygiene in a dense urban slum. With no emissions to the environment, we have a high degree of containment of fecal pathogens. Nobody has to buy water (river water will be good enough to replace any lost water in the system) and still there will be water enough for flushing, anal hygiene and hand washing.

4) We are reengineering the blue diversion toilet for the next field test in February-March 2014 and already then it will look quite different. In the short development time, which we have had available (from July 2011), it was not possible to get everything perfect from the beginning - and it will probably not be in February either.

I hope that this information is suitable to answer your questions. And I would like to thank Arno Rosmarin and the other organizers for setting up the webinar, which I enjoyed very much. It was great to hear the news from the colleagues.
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)
Last Edit: 18 Sep 2013 20:06 by muench.

Re: Sanitation Experts Webinar Stockholm Environment Institute Sept 12 2013 17 Sep 2013 14:50 #5673

  • canaday
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Dear Tove,

Thank you for your helpful response.

1) I look forward to seeing the new version of the feces cartridge. This is a big challenge to make the feces disappear and control smell without cover material.

With respect to volumes and maintenance frequency, we also have to remember that people will have parties from time to time. Could the users have extra cartridges on hand and change them themselves when needed?

(You may want to dust the interior of the empty cartridges with finished fecal compost to introduce beneficial decomposer microbes, plus it may be beneficial to add another dusting of it after each use, for the same inoculation and to help control smell.)

2) Please allow me to retract my disparaging comment about the use of recycled wash water. This is one of the great strengths of your design, which allows it to stand alone anywhere, without constantly adding more water or dealing with effluent.
I realize that there is biological treatment given by the biofilm upstream of the filtering membrane. So you currently have a 4-barrier system (not just 3 as stated on www.diversionsanitation.com/): biofilm, artificial membrane, electrolysis, and chlorine. I would suggest that one reliable barrier should be enough and two would be great: the biological filter and the artificial membrane.
a. I see no reason for the chlorine, if the membrane reliably keeps all microbes and viruses out. The chlorine would not be good for the biofilter at all, would represent an added expense, and could from time to time run out or be neglected.
b. Electrolysis of water, per se, is the splitting of H2O by electricity into H2 and O2, but you are obviously doing something different. Please give us more info on this. Where does the electricity come from? Why is this necessary?
c. How reliable and long-lasting is the membrane? Does it have no seams with bigger holes from the needles? A stable, non-reactive, inorganic dye, with molecules or fragments the size of viruses, could be placed in the treatment unit to warn users when the membrane has become defective and needs replacement.
d. I suggest expanding the biological filtration to the clean water holding tank below, by converting it into an aquarium, with a clear panel in front of it and adding lots of aquatic plants and a couple of small, hardy fish. The plants would help to consume the nutrients that would get through the membrane, plus would foster the growth of beneficial, cleansing microbes.
www.fao.org/docrep/003/x6862e/X6862E11.htm
www.ehow.com/info_7931670_aquatic-plants-clean-water.html
www.drsfostersmith.com/pic/article.cfm?d...7&articleid=2309
The fish would eat the algae as it develops, add life and fun to the toilet, and would serve as a “canary in the goldmine”. (If the water is good enough for that fish, it must be good enough for my bum and hands.) By the way, for years now we have a fish in the rainwater tank for handwashing at our UDDT (mainly to eat mosquito larvae) and people really enjoy seeing him there, plus there are no known diseases that pass from fish to people during handwashing.
The aquarium would have a little refuge of water for the fish at the bottom, which cannot be pumped dry. I know this is a wild idea, but it would improve water quality and user acceptance, at a lower cost than electrolysis and chlorine.

bluediversionwithfish.jpg


Note from the attached drawing that I am also suggesting putting some optional poles for people to hold on to, especially thinking of the handicapped, the old and frail, and the Westerners.

Please keep us informed of the project’s advances. If I can be of any help, please do not hesitate to let me know.

Best wishes,
Chris Canaday
Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com
Last Edit: 22 Dec 2013 10:53 by canaday. Reason: English
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Re: Sanitation Experts Webinar Stockholm Environment Institute Sept 12 2013 18 Sep 2013 16:24 #5682

  • dorothee.spuhler
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Dear Tove

Thank you very much for your participating in this interesting expert chat. (for more information about the expert chat, please see here: forum.susana.org/forum/categories/139-ge...te-sept-12-2013#5624)

I really hope we can fix the sound so as it does not seem anymore that we talk at the same time. And I can only confirm that we were actually very disciplined!

In the meantime, let me ask some further questions for which was no room during the 1 hour chat:

Compared to the other presenters, you are already qui in advance concerning the aspic of reusing not only the water, but also the nutrients.
-> Can you tell us more about the technologies your are looking at for the recovery and reuse of urine and faces?

Moreover, in the business model presented, you mention and end-product price and indicated that this is has been calculated on market prices.
-> Can you give us further information regarding how you measured this market prices. I.e. where this local prices from the testing sites? And based on what: nutrient/energy equivalents?
-> Have you already been thinking of how to accessing the local nutrient market to achieve the target revenue prices or did you already establish a partnership to think about this "piece of the puzzle" (e.g. wholesalers, other, …)?

Best regards
Dorothee
Dorothee Spuhler
WG1 Co-lead
Working with Sustainable Sanitation and Water Management (SSWM) based at at seecon, Switzerland
www.sswm.info / www.seecon.ch
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Last Edit: 18 Sep 2013 20:03 by muench.

Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 24 Sep 2013 08:36 #5726

  • NaomiRadke
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Dear Everyone,

For your info, that Tove took part on the second expert chat with a group of BMGF grantees on September 12.

She took this opportunity to present the current state of the project and to answer to several project-related questions by the moderators and participants of the chat.
A video of the expert chat is available on youtube – please find it under the link below, starting exactly at Tove’s presentation. Unfortunately some sound cross-overs occurred.
youtu.be/mD1kXv_avVM?t=13m27s

Find a pdf of her presentation here:
forum.susana.org/forum/categories/139-ge...te-sept-12-2013#5624

Additionally to the information Tove and Bernhard have posted already in this thread, the following project news and questions that were raised during the chat might be interesting for you, too.

The team around Tove at Eawag in Switzerland is developing a dry source separation toilet with on-site ultrafiltration water recovery. It collaborates with EOOS, an Austrian designing company and Makarere University in Uganda. A shared toilet for 2 families was developed, for which resources are recovered at a larger scale in a Resource Recovery Plant (for 175 families). Also a logistic concept has been established for transporting dried faeces and undiluted urine from the shared toilets to the Resource Recovery Plant. From the urine, fertiliser is recovered at expense of energy generated from faeces.

With regard to the toilet design: to increase hygiene and comfort the toilet can be flushed. Urine and the flush water is not mixed but separated by a technical device. Water can be used for hand-washing as well as anal cleansing. The water is recovered on-site in the water wall of the toilet by an ultrafiltration membrane treatment tank which functions exclusively by gravity – a method developed by Eawag for drinking water production. The polluted water is pumped up with a foot pump and the ultrafiltration membrane is kept open by higher organisms grazing on the membrane so one doesn’t have to maintain it. The water comes out of the membrane virus- and bacteria-free but slightly coloured. Electrolysis then removes the colour and at the same time the traces of organic matter and produces chlorine for disinfection.

Very early in the process of designing the UDDT, they interviewed potential users in Kampala, Uganda, on their attitude towards the toilet. The general feedback was positive; the interviewed person especially liked the convenience of a water tab and the flush button.

The maintenance interface is very important so that the people collecting the urine and faeces twice a week will not be sick. The toilet can be opened only if the rim is pulled. If the rim is pulled the faeces container is sealed automatically and the urine can be pumped from the bottom of the container. The container can also be removed by the users themselves in case they are having a party with many guests, for example.

Field testing was started in spring 2013 in Kampala, Uganda, in cooperation with Makarere University. The feedback by the users was again positive, but many details needed improvement. The toilet pan looked slightly different to the initial design: People open the faeces lid with the foot and when they use the shower or flush afterwards this lid will close automatically and only the front part is flushed. This is an advantage as both washer as well as wipers can use the toilet.

The business model is set up as a rent-a-toilet model, because very few people will be able to buy the toilet. Also, they can be placed in any superstructure.
A business case in Uganda was set to see whether the cost of using the toilet of 5 cents per person per day was realistic. It is a challenge, but because urine and faeces are diverted it could be possible due to the income of selling the recovered nutrients as fertilisers. Also, it is important that there will be a profit for the entrepreneur who runs the business. Operational costs are relatively high; therefore it is necessary that funding for local maintenance is available.

Question 1: Is the membrane a very expensive unit? And what is it?
Answer 1: These are the normal membranes, which one would also use for drinking water production in a normal drinking water plant in Europe. They used to be expensive but prices have been falling a lot in the last time. 20-25 % of the construction costs of the toilet will be for the membrane but at the same time it will last for 10 years. The important thing is that the membrane will not have to be maintained (cleaning not needed).

Question 2: When you say people liked the toilet, how many people did you talk to?
Answer 2: 400 people were using the toilet, some of them only once and 6 families were using it for 2 weeks (3 x 2 families, each 2 weeks). About 1500 people were being interviewed, also about the willingness to pay, which was quite high; about as high as it needs to be in order for the toilet to be implemented. Eawag financed an additional social science study that will look into all the interviews that have been made. There will be a report, when all responses have been analysed.

Question 3: Might the toilets not be too advanced for the context in Uganda? People might be hesitant to use it. And do you know what the costs will be to set the toilet up in that local context?
Answer 3: Target costs are 500 USD per toilet and a lifetime of 10 years. The project team is currently not only improving on the design but also on the technology so that target costs can actually be reached. A mechanical engineer is working on this now and the project team hopes that they will soon get an additional grant so that they can really go into the reengineering which will need professionals. At the moment there are still too many parts.

Question 4: With regard to the business model and costs: In the current phase you are also developing a partnership with other projects for the treatment for the urine and the faeces. Do you already have any indications how feasible these end product sells and how to integrate this into the 1.3 resource recovery plant costs? Can fit with the current technologies you are looking at. And regarding the service fee of 5 cents per person?
Answer 4: They think that this is feasible. In the business plan, reasonable cost targets for the technology at the Resource Recovery Plant was set, including typical costs for operation and maintenance. At the moment, only pilot plants exist, the team used normal scaling of costs from pilot plants to industrial equipment in order to calculate the costs for a number of different technologies. There were a number of technologies that could potentially fit the cost targets. At Eawag, technologies for urine treatment is developed, whereas faeces treatment is done by other grantees (e.g. Climate Foundation). In both cases, the team is optimistic that financially viable technology can be developed. Existing technologies like anaerobic digestion of feces would also fit well together with the urine treatment at Eawag (for more information: www.eawag.ch/vuna).
For the logistics they did a model study and it showed that they could get down to around 1 cent per person per day for collection and transport. And on all of these prices and the business model they are now working on. In phase 2, they got additional funding from SDC (the Swiss Agency for Development and Cooperation) in order to set up a really robust business model. There is one part of the toilet where they have problems to get costs rapidly down and that is electrolysis. But there are so many electrolysis experts in the RTTC grant who could possibly help.

Greetings from seecon,
Naomi
// Naomi Radke
MSc Sustainable Development
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
seecon international gmbh
society - economy - ecology - consulting
Basel, Switzerland

www.seecon.ch/

check out the SSWM toolbox for info on sustainable sanitation and water management:
www.sswm.info/
Last Edit: 24 Sep 2013 10:58 by NaomiRadke.
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Re: Sanitation Experts Webinar Stockholm Environment Institute Sept 12 2013 07 Nov 2013 10:54 #6295

  • larsen
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Dear Chris

Sorry for not having spotted your questions and remarks on our post earlier. I will rush to answer them now.

1) We will be working on the final version of the cartridge later. At the moment, we are striving for a new version of the entire toilet, which will be field-tested in Nairobi in March (in cooperation with Sanergy). The smell was already no problem in the first field-tests. The little bit of energy, which we spend on a forced air-vent takes care of this. I have no doubt that the clever colleagues at EOOS and Tribecraft (a new cooperating company) will solve the problem, but you are right that it is very challenging.The idea is that people will be able to exchange cartridges themselves; exactly for the reason you mentioned.

2) You are right that in principle there are four barriers. However, the membrane is such a powerful barrier that we did not mention the biological treatment. The main function of biology in this system is to degrade the pollutants and to keep the membrane open for water.

a)+b) Please let me answer these two questions together. Electrolysis can be used for many things, not only the production of oxygen and hydrogen from water. In this system, we mainly produce chlorine in order to remove the rest of the organic matter and disinfect the water. This is important in order to remove the color from the treted water (increase acceptance and thus compliance) and to prevent re-growth. Especially Legionella could be critical, but also other pathogens could move backwards through the system. In the present system, we automatically dose chlorine when there is not enough solar energy for electrolysis. This may seem ‘too much’, but for a long time to come, we will in reality do field-experiments involving real people. How it will look in a few years when we hope for the system to be multiplied depends a lot of the experience gathered in the field and in the lab.

Chlorine in moderate amounts is no problem for the biological reactor. It will immediately be eaten up by the large amounts of organic matter in the tank. We have more problems of securing the little bit of excess chlorine in the clean water tank necessary for controlling the biofilms in the piping (in your own drinking water system, biofilms are probably controlled the same way).

c) The membrane is very reliable if not mechanically damaged. Since we have no long-time experience in the field, we cannot quantify the risk of such damages. Your idea of a warning system is very good. I am not quite sure that it is necessary; the water would probably get turbid if the membrane would get damaged. We will however keep your idea in mind.

d) We are testing your idea of biological activity in the clean water tank, albeit in a less spectacular way, without plants and without fish. It could work the way you suggest and at least reduce the requirements for electrolysis. However, at the moment, we work more concentrated on reducing the energy requirements for electrolysis. I do like your wild idea, but since we are working under extreme time constraints, they will have to wait a little - perhaps somebody else could test is?

The next version comes with a hand rail (the first working model had two).
We will inform about the next generation blue diversion toilet towards the end of March when we have done the first tests in Nairobi.

Kind regards and thanks again for all your great comments and questions

Tove
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)

Re: Diversion for Safe Sanitation - Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) 13 Dec 2013 10:38 #6692

  • bernhard
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Gates explaining (somewhat general : ) our toilet:



(skip to 5:27)
Last Edit: 13 Dec 2013 10:49 by muench.

Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 29 Dec 2013 03:01 #6841

  • canaday
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Dear Tove,

Thanks for your kind response in November, which, for some reason, I have only recently seen.

Tribecraft seems to have much to offer to the process, according to their following brochure:
www.tribecraft.ch/german/download/brochu...ibecraft_english.pdf

I continue to think that, aside from the high-tech micropore membrane, the treatment of water from hand and anus washing in the BlueDiversion UDDT could be done via natural processes and in this way be safer, more reliable (no problems of chlorine not being replenished or electric generators malfunctioning), more sustainable, and better for the environment. Natural ecosystems decontaminate wastewater, so I am trying to figure out how put an entire tiny ecosystem into the wall of the BlueDiversion.

I still would argue against the use of chlorine. Among other things, with the constant recycling, this could create the conditions to promote the evolution of strains of microbes that are resistant to chlorine, inside and outside of the membrane … and those inside could get into the general environment via membrane failure or decommissioning of old membranes. Living biological filters, in contrast, include microbes that should evolve to be more and more effective at cleaning the water over time.

Yes, the organic matter can eat up the chlorine … and make chemicals that are even more toxic. It could combine with urine to form trichloramine, which can cause asthma and other respiratory and eye problems.
erj.ersjournals.com/content/29/4/690.full

Carcinogenic chlorinated hydrocarbons (e.g., link.springer.com/article/10.1007/BF00051702#page-1, bladder cancer from chlorinated drinking water
www.ncbi.nlm.nih.gov/pubmed/7977393, brain cancer from occupational exposure)
can also be formed during this process, especially since the water being treated in the BlueDiversion would contain many more organic compounds, as compared to relatively clean drinking water sources. The danger here would be the washing of hands, anuses and genitals.

You say that the chlorine is to fight the formation of biofilms. I would suggest that biofilms should not be fought, but instead valued for their contribution to cleansing the water. The trick, of course, is to design the system such that biofilms do not block the flow of water and, if they start to do so, they can be easily cleared mechanically.

My aquarium suggestion comes from trying to think of a biological treatment of the water that would otherwise be sitting idly in the clean water tank toward the bottom of the wall. I cannot think of any type of organism that would more efficiently clean the water than a plant, especially since the nitrogen and other elements that would build up in the water are exactly what plants selectively absorb and the organism would need to be submerged in the water. Photosynthetic plants, of course, require light, so I suggest adding the transparent panel, and this would also encourage the users to keep the restrooms well lit, via windows, translucent roofs and electric lights. This would be of great benefit, given the overabundance of dark, dingy restrooms.

The small fishes (in addition to their function as fun ”canaries in the goldmine”) would eat the algae that would form on the inside of the window (to keep it transparent for light to get in and for people to see in) and nibble on the plants to harvest their excess growth and stimulate continued activity. Also, since many contaminants accumulate in the fat of animals, the fish would help to remove these (and I would not recommend ever eating these fish).

What other useful organism could you put in the clean water tank, with no light, low oxygen, and (your) chlorine? Could something like the SCOBY (Symbiotic Colony Of Bacteria and Yeast, en.wikipedia.org/wiki/SCOBY) of Kombucha live there? I have not been able to find any non-photosynthetic aquatic plant or alga. It seems you may need a lithotrophic organism, which means that it lives based on chemicals in the water. These are all microbes so they would have to be strained out of the water … but there is the Giant Tube Worm (Riftia pachyptila), from the bottom of the Pacific Ocean, which has lithotrophic symbionts that live inside it, only it grows over 2 meters long and probably requires saltwater, so not very practical for the BlueDiversion … so plants look better and better.
en.wikipedia.org/wiki/Giant_tube_worm
en.wikipedia.org/wiki/Lithotroph

I still do not understand this variety of electrolysis and it does not seem to be covered in Wikipedia
en.wikipedia.org/wiki/Electrolysis
Could you please provide a link for a similar electrolysis application? Where does the electricity come from? Is it produced via the foot pump? If it comes from a solar panel, what happens with shade from neighboring trees and buildings or when it is especially cloudy?

Does the Ultrafiltration work by gravity or does it require pressure that comes from the foot pump?

What happens to the lipids present in feces inside the BlueDiversion? Would a grease trap be called for upstream of the membrane?

The water faucet and the flush button could transmit pathogens from one user to another, so I recommend using foot pedals instead. Could the foot pump and the flush pedal be combined into one?

I would also like to suggest adding 2 sand filters to help cleanse the water: one with finer sand just after the membrane (that would flow at about the same rate), another in the bottom of the aquarium with coarser sand or fine gravel (that would not impede the pumping of the water). A biofilm would develop around each grain of sand that would remove and digest contaminants from the water.

In the interest of brainstorming to get more life and sustainability into the system, a Mycofilter (cellulose-rich material, like wood chips, corn cobs or straw, inoculated with selected fungus) could be added upstream, downstream or instead of the first sand filter that I just suggested. Paul Stamets has had great success with this in the decontamination of organic, chemical and pathogenic wastewater. Most macroscopic fungi could not live submerged into the clean water tank, but would do well in such a trickling filter. Maintenance could involve a neatly packed and sterilized burlap package of cellulose-rich material being placed periodically under the previous similar ones that would inoculate them with the right fungus.
fungi.com/pdf/articles/Fungi_Perfecti_Phase_I_Report.pdf
es.scribd.com/doc/50296487/Mycelium-Running-by-Paul-Stamets
www.wired.co.uk/news/archive/2012-06/25/...gus-oestrogen-filter (A pharmaceutical company is involved in this genetic engineering project to get pharmaceuticals out of water, but one could make a Mycofilter with the actual fungus, instead of putting the gene into E. coli.)
helda.helsinki.fi/bitstream/handle/10138...ation.pdf?sequence=1 (An interesting related dissertation.)

Please allow me to quote
(info.biotech-calendar.com/bid/97482/WSU-...-Purify-Water-Supply):
“Water purification is a serious problem worldwide. While good filtration systems exist, they can be expensive to implement and maintain (...) Chemicals such as chlorine are regularly utilized to kill off pathogens, but then the chemicals typically need to be removed or neutralized. The elegance of mycofiltration is that it performs its task naturally and adds no further contaminants to the water. In fact, the fungi actually neutralize the bacteria in the process of consuming it as food, so that the used mycofilters can be composted later without toxifying the soil. Finally, mycofiltration is inexpensive. Win-win.” 

I would be glad to do trials of an “Aquarium Filter with Plants and Fish”, a Mycofilter, and these sand filters here in Ecuador, if you like (and especially if you can cover the costs). I could set this up for testing without the rest of the BlueDiversion, although optimally I should have the membrane filter unit.

Thank you for this continued conversation and please let me know if I can be of any help. This is a great concept and it would be an honor to contribute to its success.

Best wishes,
Chris Canaday
Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com
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Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 29 Jan 2014 11:50 #7156

  • larsen
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Dear Chris

Sorry for the late answer, but as I wrote to you personally, I wanted to check a few things before I answered publically. You are raising some very interesting questions with respect to the possible accumulation of chlorinated organic compounds, which I wanted first to discuss with my colleagues.

First of all, however, I would like to emphasize that the water recovery system in Blue Diversion works exactly as you suggest it should: it is a microcosmos of micro and macro organisms, where more than 95 % of the organic material is degraded. The macro organisms keep the filter open and the system is totally self-organizing; all it takes is air for keeping the filter aerobic. Also for this purpose we need electricity; not only for electrolysis. The biofilm on the filter does take part in the degradation and we are not fighting it.

You have some questions with respect to the different types of organic matter in the wastewater. In the water recovery unit of Blue Diversion, these different types are all degraded, exept for the very resistent molecules.

The water filtered in the system is safe, but it may not stay so. Pathogens can enter the system from the tap and the shower head and live on the rest of the organic matter. The water is also not too appeling as it is slightly colored. In order to protect the users against the regrowth of pathogens, we apply electrolysis for the production of chlorine. Chlorine is the gold standard for obtaining hygienic water and it also has the pleasant side effect of removing color from the treated water. This makes it much more appealing to wash your hands with the water.

In principle, we do not see any difference to normal chlorination of drinking water. We do not expect any accumulation of chlorinated compounds, but expect those to be degraded in the biological treatment. This, of course, we will have to prove - thank you for rising the question. With respect to chlorine resistance, the problem in water pipes is the biofilms and there the risk of resistance would be equally high.

In your questions, you indicated that biofilms could be a problem for clogging of the pipes. This is certainly not a problem here. The water is treated to a high degree, but in order to prevent microbial growth, we need to get lower than 10 ng of COD. This is not possible in the type of systems we are discussing here.

I am rather doubtful about the aquarium idea and I do not think it would solve the problem of pathogen regrowth. Reintroducing organic matter does not seem such a good idea, apart from all the practical problems, which you mention yourself.

We are not using a food pump for opening the water tap and have also removed the ones originally in the toilet. Our first field test revealed that small children had problems using the pump. This is also a practical problem of getting the price and the size of the toilet down. In a few weeks, the pictures of the new toilet will go online on www.bluediversiontoilet.com and you will see that the touching point is very small. Combined with hand washing with soap, we hope that this will minimize cross contamination between users (please remember: this is not a public toilet, but a toilet shared by up to 10-12 people, ideally 1-2 families).

Another comment on the foot pump: The ultrafiltration membrane works with gravity and the water has to be pumped up. For the reasons mentioned above, this is now done by an electrical pump and not by a foot pump. Still, however, energy consumption is very low.

You suggest to introduce the mycofilter, which can not survive submerged. We tried out a trickling filter in the beginning of the project, despite the advice from a number of experienced engineers that it would be eaten by flies. They were right, so we are reluctant to try yet another trickling filter.

For the practical information on electrolysis for chlorine formation: This is an old technology used in the chlor-alkali industry for producing chlorine from chloride (see, e.g. wikipedia for an overview). I am surprised that you do not find this technology on the internet; there are so many sites that I hesitate to choose one, but see e.g.
phoenix.about.com/cs/wet/a/saltpool01_2.htm for a common application (producing chlorine from kitchen salt for residential swimming pools). The chemistry of electrolysis is of course complex and the choice e.g. of electrodes, potential applied and distance between the electrodes all influence the result. We have optimized a commercial system for very low energy consumption, but there is still work to do to lower the costs of the system.

In order to get the toilet out as soon as possible, we have already industrialized the water wall. This means that there is little room for changes, although we are experimenting with some additional surfaces for decreasing the organic matter in the effluent even more. However, we are operating the water recovery system without any sludge removal (another advantage of the system from the point of view of maintenance), which leaves relatively little scope for further biological degradation.

We do of course hope that other people will help further develop the system, but at the moment we concentrate on understanding the user experience and we look very much forward to the coming field tests in Nairobi, which will be conducted in cooperation with Sanergy.

I hope I succeeded in answering your questions. Thank you for your interest

Kind regards
Tove
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)
Last Edit: 29 Jan 2014 11:51 by larsen. Reason: I discovered a typing mistake

Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 30 Jan 2014 22:27 #7173

  • canaday
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Dear Tove,

Thank you for getting back to me, although our perspectives are widely divergent.

What macro organisms will be inside the membrane?

The link you gave does not explain the process of this type of electrolysis. It does however state "Through electrolysis, chlorine is produced and immediately injected into the pool circulation system. These units are messy and produce by-products that are not simple to dispose of."

I think I may have found an explanation of your style of electrolysis, if this is the Cloralcali Process:
CloralcaliElectrolysisfromWikipediaChlorine.jpg


en.wikipedia.org/wiki/Chlorine

You have given no explanation why chlorinated hydrocarbons should not accumulate in the water, growing constantly in concentration in the water the users occupy to wash their hands and genitals. This is the same family of chemicals as DDT and Dioxin, which includes some of the most toxic chemicals known, and they do not biodegrade easily.

The same Wikipedia page states:
"Organochlorine compounds as pollutants

Some organochlorine compounds are serious pollutants. These are produced either as by-products or end products of industrial processes which are persistent in the environment, such as certain chlorinated pesticides and chlorofluorocarbons. Chlorine is added both to pesticides and pharmaceuticals to make the molecules more resistant to enzymatic degradation by bacteria, insects, and mammals, but this property also has the effect of prolonging the residence time of these compounds when they enter the environment." (Or in this case, the recycling aquatic ecosystem of the Blue Diversion.)

I see no response to my suggestion of adding a sand filter (with its helpful biofilm). I think that this would contribute considerably to the visual clarity of the water and the elimination of substances that pass through the membrane (e.g., nitrates), which I think are the most important two factors between the membrane and the user, more than the risk of pathogens swimming upstream (against which a one-way valve could be added).

I suggest you consider making the water recycling optional, with a switch to turn it on. For example, in times and places where there is abundant water, the Blue Diversion could be piped in and the small amount of effluent could go a Vegetated Sand Bed. The same unit, in times of water shortage, could be switched to recycling. One problem would be the stable growth of the beneficial microbes. So it may be simpler to produce 2 models.

I also suggest you consult with several good microbiologists about the chlorine-resistant strains of microbes that may develop.

Good luck. I will stop interrupting you. I think all my points are still valid and they can be reviewed whenever one likes, here on the Forum.

Best wishes,
Chris
Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com

Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 03 Feb 2014 10:46 #7206

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Dear Chris

Just a short reply to some of your main points.

We will be testing whether the chlororganic compounds are accumulating or not.

As to the macroorganics: In similar systems, we find that nematodes and oligochaetes play a large role.

As I wrote, we are testing large surfaces for promoting biological growth after the filter. We will not use sand, but activated carbon. There is not enough degradable organic matter to eliminate nitrate at this step, and the water is oxygenated so it would not happen anyway. Nitrate is not really a problem and it does not accumulate.

The Blue Diversion toilet is intended for densely populated urban slums where there is no space for vegetated sand beds and where water will often not be able to infiltrate.


Kind regards
Tove
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
Urban Water Management
Dübendorf, Switzerland

www.diversionsanitation.com

Fresh from the Press: Source Separation and Decentralization for Wastewater Management
(www.iwapublishing.com/template.cfm?name=isbn9781843393481)
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Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 04 Feb 2014 13:12 #7232

  • canaday
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Dear Tove,

I am glad to hear of the macroorganisms. I think the Oligochaetes may be easier to manage and more acceptable to users and maintenance staff.

I may have jumped to the conclusion of nitrates, but nitrogen in general needs to be removed from the water ... and the Oligochaetes should help with this to some extent.

I do not remember activated carbon being mentioned before, but this is a good option. Is there a reason to not also have a sand filter?

I consider the Blue Diversion Toilet to have enormous application in many situations, including up-scale, urban homes in developed countries. In addition, not all developing countries are stressed for water. For this reason, it would be good to have a couple of different models. A non-fully recycling model could still use filtered hand and anal washwater to flush the system, thus demanding and emitting only tiny amounts of water.

I wish you great success.

Best wishes,
Chris
Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com
Last Edit: 05 Feb 2014 14:18 by canaday. Reason: English

Re: Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 18 Mar 2014 08:06 #7863

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Hello,
this is the first in a series of blog posts about testing the blue diversion toilet with Sanergy in Mukuru, Nairobi. Thoughts, comments and questions are welcomed.

Cheers,

Mark

www.bluediversiontoilet.com/blog.html
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Re: Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 25 Mar 2014 15:34 #7964

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There was significant interest in the Blue Diversion toilet at the Reinvent the Toilet Fair in Delhi last week. See a video here:



and go to www.bluediversiontoilet.com/safe.html for further technical information.

Best regards,

Eberhard


++++++++++
Prof. Dr. Eberhard Morgenroth
ETH Zurich
Chair of Process Engineering in Urban Water Management
Institute of Environmental Engineering (IfU)
www.ifu.ethz.ch/SWW

and

Eawag
Process Engineering (Room BU-B13)
CH-8600 Duebendorf, Switzerland
www.eawag.ch
www.eawag.ch/about/personen/homepages/morgeneb

+++++++++++++

Some photos from the exhibit (added by EvM):

The Blue Diversion exhibit at the Toilet Fair by Sustainable sanitation, on Flickr

Blue Diversion Toilet Prototype by Sustainable sanitation, on Flickr
Last Edit: 25 Apr 2014 09:57 by muench.
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Re: Grant on Advanced Toilet with On-Site Water Recovery (Eawag and EOOS, Switzerland and Austria) ​– currently testing the blue diversion toilet in urban slums 18 Jun 2014 11:08 #8990

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Dear Forum Users,

This is to announce that the Blue Diversion Toilet has won the Project Innovation Awards 2014 assigned by the International Water Association (IWA).

Please find more information about the award on the website: http://www.iwa-pia.org/pia_award_eu.html

and about other categories' Prize Winners in the .pdf attached.

All about the Blue Diversion Toilet can be found on:
www.bluediversiontoilet.com

We would also like to remind you that the award will be presented soon, on 25th June 2014.

[posted by Sebastian Klos]
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Posted by a member of the SuSanA secretariat held by the GIZ Sustainable sanitation sector program
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Last Edit: 18 Jun 2014 16:38 by muench.
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