The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications since 2016

  • AParker
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  • Lecturer in International Water and Sanitation at Cranfield University, working on many apsects of urban water and sanitation, including leading Cranfield's response to the BMGF Reinvent the Toilet Challenge.
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

Thanks for all your responses!

Prince and Orchha - We're still in the development stage but I hope we'd be able to brign it to Kenya, Uganda and India in the future.

Chris -
Thanks for your suggestions. At the moment we're focussed on getting the combustion working effectively, rather than the reuse of the ash. The amount generated will just be a few grammes a day in each household - which of your suggestions would work at that scale?

The liquids will pass over a weir and drain into a small chamber where the membranes are. They will be replaced by the service technician once every 3 months. The used filters will be taken bach to base, regenerated and sent out to another customer.

We're still in an early stage of development, but obviously cost minimisation and reliability are high on our agenda.

Happy to answer any other questions!

Alison Parker
www.nanomembranetoilet.org
Apply to study our MSc in Community Water and Sanitation:
www.cranfield.ac.uk/courses/masters/comm...-and-sanitation.html
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  • canaday
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

Dear Alison,

I would say that all of my suggestions for using the ashes would be feasible, especially handwashing ... and this would make your sanitation system all the more complete. If the users want to do something big with the ashes, they can store it up and ask their neighbors to give them more ashes. The last thing we should do is to tell the users to put a resource in the garbage.

What will happen to the liquids that get taken out of the toilets by the technicians?

I still do not understand where the nanomembrane is?

Best wishes,
Chris Canaday

Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com
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  • AParker
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  • Lecturer in International Water and Sanitation at Cranfield University, working on many apsects of urban water and sanitation, including leading Cranfield's response to the BMGF Reinvent the Toilet Challenge.
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

Thanks Chris - we'll bear your suggestions for ash use in mind as we move towards implementation.

The compounds that are rejected by the membrane will flow back into the main holding chamber. The water will be clean enough to use in the house. No liquids are removed by the technicians.

The membrabes are green on this diagram at the bottom right of our home page:
www.nanomembranetoilet.org/

Alison Parker
www.nanomembranetoilet.org
Apply to study our MSc in Community Water and Sanitation:
www.cranfield.ac.uk/courses/masters/comm...-and-sanitation.html
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  • AParker
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  • Lecturer in International Water and Sanitation at Cranfield University, working on many apsects of urban water and sanitation, including leading Cranfield's response to the BMGF Reinvent the Toilet Challenge.
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

The membrane module is a core component of the toilet, allowing us to get clean water from faecally contaminated urine. Experimental work has defined the tube-side mass transfer coefficient derived in hollow fibre membrane contactors of different characteristic length scales (equivalent diameter and fibre length) under the slow flow conditions that are expected in the toilet.

The work is described in detail in a paper in the Journal of Membrane Science, which is free to download:

Yang, C.Y., E. Mercer, F. Kamranvand, L. Williams, A. Kolios, A. Parker, S. Tyrrel, E. Cartmell, E.J. McAdam Tube-side mass transfer forhollow fibre membrane contactors operated in the low Graetz range , Journal of Membrane Science 523, 235–246

Alison Parker
www.nanomembranetoilet.org
Apply to study our MSc in Community Water and Sanitation:
www.cranfield.ac.uk/courses/masters/comm...-and-sanitation.html
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  • AParker
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  • Lecturer in International Water and Sanitation at Cranfield University, working on many apsects of urban water and sanitation, including leading Cranfield's response to the BMGF Reinvent the Toilet Challenge.
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

The screw is a critical component in the toilet, allowing the settled solids to be removed from the bottom of the holding chamber and transported towards the gasifier/combustor. This separates them from the liquid. Traditional source separating designs require a change of user behaviour, whereas our aspiration is to make using the Nano Membrane Toilet a comparable experience to using a "conventional" water-flush toilet.

We have been doing experiments on the screw to determine the best charactertistocs to transport the solids but minimise the transport of liquids. This has included changing the taper of the central shaft, makig the flights closer together near the top of the screw, and changing the rotation speed. the results are described in this recently published, free-to-access paper:

Mercer, E., P. Cruddas , L. Williams , A. Kolios , A. Parker , S. Tyrrel , E. Cartmell , M. Pidou and E. J. McAdam (2016) Selection of screw characteristics and operational boundary conditions to facilitate post-flush urine and faeces separation within single household sanitation systems , Environ. Sci.: Water Res. Technol., 2, 953-964

Alison Parker
www.nanomembranetoilet.org
Apply to study our MSc in Community Water and Sanitation:
www.cranfield.ac.uk/courses/masters/comm...-and-sanitation.html
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  • Ecowaters
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

Aren't the membranes expensive?

How much energy is used to push the liquid through the membrane?

MBR for wastewater is running into all sorts of challenges in the U.S.

Book writer, researcher, workshop presenter, eco-toilet vendor, market transformer

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  • AParker
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

We're still deciding on which membrane to use, but all the ones we are testing are off-the-shelf, none are bespoke. One of the key factors is selectivity - the more selective the membrane, the more energy is required, byt the better quality the output water.

Just to note that's its not an MBR process - more similar to pervaporation.

Alison Parker
www.nanomembranetoilet.org
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  • prince
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Re: Reply: PhD Scholarship: Field testing a novel waterless toilet

As interested persons in this project,we request if such can be replicated in Uganda or Kenya it can be of great value to communities of two countries.We too have great passion to recycle human urine into valuable products to generate job opportunities and reduce poverty. We shall be happy to have partnership with you on this project. Prince Maloba
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  • muench
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Re: Reply: PhD Scholarship: Field testing a novel waterless toilet

Dear Prince,
You might have overlooked Alison's response to your earlier request. She wrote on 6 December 2016:

Prince and Orchha - We're still in the development stage but I hope we'd be able to brign it to Kenya, Uganda and India in the future.

So I think you still need to be a little bit patient. :-)
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  • JKMakowka
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Re: Reply: PhD Scholarship: Field testing a novel waterless toilet

Have you thought about making the membrane part modular? I guess in many cases the water recycling aspect is not that vital and a more simple filter for soil infiltration would do. However in cases where the water recycling is needed, a larger version that can also recycle various sources of grey-water in addition would be a good idea?

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  • JackAqucell
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

Dear Alison, dear Ecowater and all,
The idea of turning human waste into usable water, dry fertilizer and energy is great and the prototype of your design is beautiful. Congratulations!
As a membrane manufacturer, I agree with what Ecowater concerns about, the energy cost.
Very few water would go through the membrane fiber unless there is a pressure to force them to. To maintain the pressure consumes ennergy.
I see Alison and her team has been working on it to find the proper "selectivity". I think it might depend more on field data and sometimes, individual cases may differ a lot from each other.
Then it comes to the pollution resistance ability of the membrane itself. For a daily device for everyone, the least troublsome way is that it can clean itself when the fouling against the membrane module reaches a redline and we press a button for it to clean itself for two minutes and then it could go for another week. During this week, we may call and wait till the technician to arrive and replace it with the regenerated membrane module.
The called technician could be delayed by everything while the call of nature is absolutely not.
We have projects in Cambodia for membrane treated drinking water. The energy problem is tackled with bicycle generator.
Membrane technology opens a new gate to solve clean drinking water crisis and I'm happy to see that Alison and her team is working with it on human waste problem. I would be glad to share what we found in our application practice for this great idea.
Good luck!
Jack
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  • AParker
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  • Lecturer in International Water and Sanitation at Cranfield University, working on many apsects of urban water and sanitation, including leading Cranfield's response to the BMGF Reinvent the Toilet Challenge.
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Re: The Nano Membrane Toilet (Cranfield University, UK) - latest results and publications in 2016

Thanks to all for your comments and interest!

The membrane will be modular. However, we would be nervous about installing the toilet without the membrane as the untreated liquid component will still be pretty nasty - basically feacally contaminated urine, which could cause significant groundwater contamination, depending on the local conditions. Our energy modelling suggests we will be able to get enough energy out of the faces to enable the membrane processes.

The membranes are hydrophobic so fouling is not too much of a problem (a paper on this is in preparation).

Alison

Alison Parker
www.nanomembranetoilet.org
Apply to study our MSc in Community Water and Sanitation:
www.cranfield.ac.uk/courses/masters/comm...-and-sanitation.html
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