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/

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

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!

Hello Alison, If you're interested in a trial in India, we want to replace the three EcoSan dry toilets at the Orchha Home-stay with sit-down waterless toilets for our host families and guests. We can of course introduce these in Almora, Uttarakhand as well where I now live and where the municipality needs to install a number of new public toilets. Please let us know if these are being manufactured in India now and who we can contact for renting or purchasing. Thanks. Asha D'Souza www.orchha.org and www.greenhillsalmora.org

Dear Alison,

Congratulations on these advances and your excellent new video.

I would like to suggest that we avoid putting any product of our toilets into the trash, taking into acoount the general chaos or absence of solid waste management in most parts of the world.

The ashes from the combustion of the feces could be productively used in a variety of ways, including:
-- Washing hands, dishes, pots, etc.
knowledgepoint.org/upfiles/14153226341780206.docx
-- Making soap,
-- Fertilizing soil, esp. mixed with urine collected separately from the toilet,
news.nationalgeographic.com/news/2009/09...-ash-fertilizer.html
-- Controlling insects, such as ants,
-- Giving them to a cement factory or mixing them into concrete while doing masonry
(Reportedly ashes can replace 20-40% of Portland cement
www4.uwm.edu/cbu/abstracts/03-513.pdf
www.sciencedirect.com/science/article/pii/S2090123214000939
www.motherearthliving.com/mother-earth-l...geid=1#PageContent1
Research was mostly done with "fly ash" from burning coal, which should not be too
different from fecal ash).
-- Or just burying them in the yard would be simple and innocuous.

What happens to the substances that get filtered out of the water? How often do those filters need to be backwashed, maintained or changed?

How long do you think this toilet can function without anything breaking or needing maintenance?

What is the target, unsubsidized price tag for this toilet?

Please remind us where the nanomembrane is.

Best wishes,
Chris Canaday

Can they replicate this project to Kenya or Uganda so that poor families can have good toilets. Thank you
Prince

Cranfield University's Nano Membrane Toilet project has landed a major funding boost to secure the next phase of development of a novel and sustainable sanitation solution for the benefit of the huge number of people around the world who currently have no hope of being able to access a clean and affordable toilet in their home.

Dr Alison Parker, from the Cranfield Water Science Institute, said; "This is a great moment; the new funding from the Bill & Melinda Gates Foundation will support our research teams in water, energy and design to tackle the considerable challenge of turning the laboratory prototype Nano Membrane Toilet into a product for the marketplace."

The Nano Membrane Toilet uses a waterless flush; a unique rotating mechanism that drops the waste into a holding tank whilst simultaneously blocking odour and the user's view of the waste. The solids then settle to the bottom of the tank, while the liquids float on the top. The solids are transported out of the tank by mechanical screw into a combustor where they are burnt and transformed into ash. The heat generated can be converted into electricity which is used to power toilet operations, and any residual energy is used for charging mobile phones or other low voltage items. The liquids pass over a weir in the holding chamber and into the membranes bundle. The unique nanostructure membrane allows clean water to be extracted from the waste which can subsequently be used in the household for washing or watering plants.

The toilet is designed for single-household use (up to ten people) and accepts urine and faeces as a mixture. Developed with the aspirations and needs of the user in mind, it is small and easy to transport to locations where there is no access to a water supply and sewer. In comparison to the public toilets relied on by urban communities around the world, a household toilet offers convenience, dignity and security especially for vulnerable groups like women, the disabled and the elderly.

A new video has also been released highlighting some of the recent innovations and improvements to the toilet.



With World Toilet Day (19th November) helping to raise awareness and inspire action to tackle the global sanitation crisis, Cranfield's toilet is attracting interest from around the world, and was recently showcased at the Toilet Investment Summit in Mumbai, India.

The Nano Membrane Toilet will use gasification to convert the faeces to ash (rendering all pathogens harmless), but also providing an energy source for the toilet processes. The Cranfield team have been working to understand the science behind the gasification of faeces to inform the final design of the gasifier. The first piece of this work is now published in the journal "Energy Conversion and Management" - open access of course!

T. Onabanjo, K. Patchigolla, S.T. Wagland, B. Fidalgo, A. Kolios, E. McAdam, A. Parker, L.Williams, S. Tyrrel, E. Cartmell, Energy recovery from human faeces via gasification: A thermodynamic equilibrium modelling approach, Energy Conversion and Management 118:364-376

www.sciencedirect.com/science/article/pii/S019689041630245X


Abstract
Non-sewered sanitary systems (NSS) are emerging as one of the solutions to poor sanitation because of the limitations of the conventional flush toilet. These new sanitary systems are expected to safely treat faecal waste and operate without external connections to a sewer, water supply or energy source. The Nano Membrane Toilet (NMT) is a unique domestic-scale sanitary solution currently being developed to treat human waste on-site. This toilet will employ a small-scale gasifier to convert human faeces into products of high energy value. This study investigated the suitability of human faeces as a feedstock for gasification. It quantified the recoverable exergy potential from human faeces and explored the optimal routes for thermal conversion, using a thermodynamic equilibrium model. Fresh human faeces were found to have approximately 70–82 wt.% moisture and 3–6 wt.% ash. Product gas resulting from a typical dry human faeces (0 wt.% moisture) had LHV and exergy values of 17.2 MJ/kg and 24 MJ/kg respectively at optimum equivalence ratio of 0.31, values that are comparable to wood biomass. For suitable conversion of moist faecal samples, near combustion operating conditions are required, if an external energy source is not supplied. This is however at 5% loss in the exergy value of the gas, provided both thermal heat and energy of the gas are recovered. This study shows that the maximum recoverable exergy potential from an average adult moist human faeces can be up to 15 MJ/kg, when the gasifier is operated at optimum equivalence ratio of 0.57, excluding heat losses, distribution or other losses that result from operational activities.

Hi Mwaniki,

Thanks for your interest in the Nano Membrane Toilet. It's not actually so different, really the main thing is the addition of the gasifier and pelletiser.

The ash will be disposed of with the household solid waste - and of course there will be a way of releasing it form the gasifier. The design is still under development so this is just representative!

You're welcome to use the text on the front page of our website for your article:

www.nanomembranetoilet.org/

Alison

Hi Dr Parker

Thanks for publishing the modified diagram of the nano membrane toilet. This version is very different from the one that was reported in the Africa Water, Sanitation & Hygiene Jan – Feb 2016 edition.

However, am curious to ask what happens to the ash after the waste is turned into energy in the gasifier. I can’t see any release screw underneath the chamber.

And if you could kindly let us have the accompanying text (maybe 200 words or thereabout), we could reprint it in the oncoming edition of the above publication for the benefit of our audience.

Regards / Mwaniki

After a period of intense technical development of the Nano Membrane Toilet we're pleased to be able to share our latest diagram of the system configuration:

2.bp.blogspot.com/-s6oBxGBBvpA/VyyO6Gbft...iption%2Bdiagram.jpg

We're also starting to publish some of the science behind the Nano Membrane Toilet in open access academic journals, which I will share shortly.

Hi Eng. Mughal and other

Kindly note that the Nano Membrane Toilet has also featured on page 30 in the current edition of the Africa Water, Sanitation & Hygiene Vol. 11 # 1 which has just been posted in the forum.

Please observe “Alternate toilet options” e.g. Report on Dallo Ado UDDT latrines and tiger worms latrines in Ethiopia and Monrovia in Liberia on the same page.

Kind regards

Mwaniki