Pellets from UDDT/composting toilet wastes?

  • Kevinkuhn
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Pellets from UDDT/composting toilet wastes?

Hi,

I was wondering if there are any results and evidence if pelleting from wastes of UDDT and container based dry-toilets (no diversion, wood chips as cover material) is possible and viable?

Every time I come across the topic of pellets it is in regards to either FS or any other bio-wastes. If it is possible, than this might be a good solution for creating an income stream after treatment for container based toilet systems. I am looking into something similar to the LaDePa Process from the Kwazulu Natal University. www.susana.org/_resources/documents/defa...882606.%20et%20alpdf

In regards to the container based toilets I attached a picture of the waste that we collected from festival toilets in Germany. After collection we drain the material with a filter pump. The material at that point is still wet, but not saturated (~80%), and can be transported with shovels or excavators. I guess for pelleting, the material should be dried with solar energy and/or ventilation beforehand.

I can imagine as well, that the wood chips themselves are well suited for this process because of the higher calorific value. Probably even more effective than in composting.



Any experiences, any thoughts?

Best
Kevin

Non-Water Sanitation e.V.
www.nonwatersanitation.de
www.nonwatersanitation.org (english)

EcoToiletten - Rental for public composting toilets for cities and music festivals in Germany
www.ecotoiletten.de
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  • hajo
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Re: Pellets from UDDT/composting toilet wastes?

hi Kevin,

just some clarifications:

I was wondering if there are any results and evidence if pelleting from wastes of UDDT and container based dry-toilets (no diversion, wood chips as cover material) is possible and viable?


You speak of different toilet types: UDDT or dry toilets (no diversion),or? If so the FS should be of different moisture content (UDDT: 65%; dry toilet (i.e. no flush water, but faeces and urine mixed): 93%). The woodchips of course will reduce the mositure content of both.

The material at that point is still wet, but not saturated (~80%), and can be transported with shovels or excavators.

Is it 80% moisture or 80% solid content? I guess the first, but I am not sure as UDDT FS is drier than that.

I learned from the LaDePa manufacturer that they require a moisture content of 25 to 35% for the successful process in their machine. If the FS is drier than that the extruder cannot produce the pellets, if the FS is more watery the pellets produced by the extruder form back into a clumsy heap which cannot be dried after on the belt which runs through the hot air and infrared.

as I said, for clarifications first before we can discuss further.

cioa
Hajo

We can't solve problems by using the same kind of thinking we used when we created them.
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Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction.
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  • Kevinkuhn
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Re: Pellets from UDDT/composting toilet wastes?

Hi Hajo,

I see that my question might have caused some confusion. I was mainly asking if there has been any project with using any of the two materials. In the projects that I lead and consult we use either UDDT, Urine Separation Toilets, or Container Based Dry Toilets. Therefore I wanted to know if there are experiences for any of the materials, which all share that cover material is added.

In the Container Based Dry Toilets that I talk about, we have a moisture content of 80%. But of course this number will differ and depend on the percentage and texture of cover material that is added. It can definitely go up to 90-95%. For UDDTs the number will obviously be lower but still include a high variance. In the end it will be very different from context to context, but I assume that it is very similar to fecal sludge in regards to the moisture. I suspect as well that solar drying is necessary before pelletizing.

If nobody is aware of such an application in the past, I guess it is time to test this =)

Regards
Kevin

Non-Water Sanitation e.V.
www.nonwatersanitation.de
www.nonwatersanitation.org (english)

EcoToiletten - Rental for public composting toilets for cities and music festivals in Germany
www.ecotoiletten.de
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  • hajo
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Re: Pellets from UDDT/composting toilet wastes?

Hi Kevin,

thanks for the clarification. I am very interested staying in contact with you as I am also thinking about the best way turning FS from OSS systems (UDDT, cesspit (container-based, dry), Otji, pit latrine) into bio-fuel. If that could be done in smaller, descentralised processing units transport could be reduced considerably and the end product be sold right from the treatment works to people using it in cooking stoves replacing charcoal. Acc. to KwaZulu-Natal University research (Prof. C.A. Buckley), LaDePa pellets have a calorific value (~ 19 MJ/ kg dry) which is close to wood, a bit less than charcoal and half of diesel and coal (without woodchips having been added).

As indicated in my previous posting, the LaDePa requires a moisture content of 25 to 35% to function properly. The question we have to resolve is how to put drying, pelletising and hygienising in the right order. In the LaDePa they dry before to the required level, then pelletise, then dry further (hot air from the generator) and hygiense by infrared. And the pelletising is necessary because when drying FS it quickly forms a crust which prevents further temperatur increase and drying in the core of the FS. The pelletising creates bodies which have a small volume compared to the surface, so that the core has reached temperature and moisture reduction before the crust has closed.

If nobody is aware of such an application in the past, I guess it is time to test this =)

The LaDePa is one such application, but I guess you have no intention importing it to Germany, or? What else you can imagine to test?

ciao
Hajo

We can't solve problems by using the same kind of thinking we used when we created them.
Albert Einstein
Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction.
E.F. Schumacher
Everything should be made as simple as possible, but not simpler. :-)
Albert Einstein
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  • FroggiVR
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Re: Pellets from UDDT/composting toilet wastes?

Hi Kevin,
Have you heard of the work of Sanivation ? They have a model that involves solar-concentrated drying of UDDT solids and pressing the waste to form charcoal-like briquettes for cooking.
Cheers,
~Froggi

Oregon State University
Environmental Sciences
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  • hajo
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Re: Pellets from UDDT/composting toilet wastes?

Hi Froggi
(who are you? would you mind introducing yourself, please)

hi Kevin,

I wonder whether you will get response from Sanivation (Kenya! beware there is a different activity in India with the same name). The last contribution from Sanivation (Kenya) on the Forum is of 2016. And when I tried to contact them in 2017, they referred me to emails and outside the forum which I found weird. When you use the forum to 'advertise' yourself you should also respond to queries on the same channel. I am not sure at what state of activity they are now but if you find out, please let me know as I also look for small scale processing of FS (300 kg/day).

On their website they announce their 'plans' as

"By early 2016 we expect to showcase our model at scale in Naivasha, Kenya"

which indicates that the site is not very up to date.

ciao
Hajo

We can't solve problems by using the same kind of thinking we used when we created them.
Albert Einstein
Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction.
E.F. Schumacher
Everything should be made as simple as possible, but not simpler. :-)
Albert Einstein
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  • FroggiVR
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  • Froggi VanRiper is a PhD student in Environmental Sciences at Oregon State University.
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Re: Pellets from UDDT/composting toilet wastes?

Hello Hajo,
I am a PhD student at Oregon State University. My topic of study is sustainable sanitation programs in displaced-persons settlements and scenarios. Perhaps I should introduce myself to the community at large in a separate post!
Regards,
~Froggi

Oregon State University
Environmental Sciences
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  • ediauemma
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Re: Pellets from UDDT/composting toilet wastes?

Hi Froggy,

Its is great to have you in the forum. I am Emmanuel, I work for GOAL in Uganda. We currently have a very serious refugee situation in Uganda (the Southern Sudanese and DR Congo refugees) and I guess my Country would be a very good case study for your PhD thesis is indeed you have not zeroed in to a particular case yet.

I am following the rest of the discussion on this topic because we too are exploring the various possibilities of re-using FS and Municipal waste. Keep the thoughts coming.

Emmanuel
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  • ainulfirdatun
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Re: Pellets from UDDT/composting toilet wastes?

Hi Kevin,

This could also work from other source of FS as long as the raw material meets the criteria of the pelleting process e.g. moisture content I guess.

The article here ( ‘LaDePa’ process for the drying and pasteurization of faecal sludge from VIP latrines using infrared radiation --it is open source!) says that sawdust played an important role in adjusting the plasticity of the FS.

I am curious about this topic and hope to hear more inputs from others.

Regards,
Ainul

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