Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

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  • Linda2019
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  • Dr Linda East is an Honorary Associate Professor in Health Sciences (Nottingham University, UK) and a Trustee of Dream Big Ghana Foundation (UK).
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Thanks again, Heiner - and thanks to you too, Jenna. What an amazing topic for your PhD, and let's hope we find a way to scale up your amazing technology.  More food for thought for us - thank you!
Linda
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  • Heiner
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Thanks very much Jenna,

at least for me a very valuable information and the picture in my mind becomes clearer and clearer..... And the situation on site will decide which way to go.

And your information gives me a little hope for the situation in central europe. Sometimes I doubt if we ever will change our habit. But you and other young people here work on it. Just great! And perhaps Durban, India, Ghana and China force our sluggish society to get on the move..... towards sustainibility.

Cheers,

Heiner
Heiner, the old farmer.....
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  • Jsenecal
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  • Bioresource engineer with PhD in Safe Nutrient Recovery from Human Urine – System and Hygiene Evaluation. Now working on the commercialization of the urine drying technology.
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Dear Chris and others,

Thanks for sharing  your experiences and bringing up the option of stabilizing urine. At the Swedish University of Agricultural Sciences, we have worked with increasing the pH of urine to above 10 to stabilize the urine so that we can evaporate the water to produce a dry, nitrogen rich, fertilizer from the urine (and decrease the mass to <10%). At pH 10 and above, the urease enzymes are blocked and the urea is not converted to ammonia (volatile and odorous form of nitrogen). We have tested various alkaline compounds to raise the pH and ash has been overall the nicest to work with in terms of odour control. We've used a ration between 20-50 parts urine to 1 part ash (20-50 g ash per L urine). Lime (calcium hydroxide, Ca(OH)2)) also works well at 20 g per L of urine (pH is then >12; need to be careful using this product - the dust from lime is a hazard for skin and if inhaled). After increasing the pH, we remove the water (urine is >90% water) with active ventilation and added heat to accelerate the evaporation (to max 40-50 degrees C, higher than this urea starts to thermally convert to ammonia). Note the urease enzyme is only blocked at pH 10, if the pH drops below 10, then the enzymes can reactivate and start to hydrolyze (convert) the urea to ammonia again.

You can look at the image attached for an example of UDDT we had set-up at our office and check out this link for more details: theconversation.com/we-developed-a-simpl...-how-its-done-150309

Hope this helps!
Cheers,
Jenna
_____________________________________
Jenna Senecal, PhD.
Environmental Engineering Grp.
Swedish University of Agricultural Sciences
Research: blogg.slu.se/kretsloppsteknik/
Company: sanitation360.se
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  • Heiner
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Dear Linda and others,
exciting for me to learn so much by an existing real sanitation project and the questions which show up during an evaluation.  My question today:
You have the twin chamber system an expect somehow the not operating one is undergoing a composting process. What it will do in a way. But a controlled composting means you have to control and steer the process by adding moisture (if too dry) and air (if stored too tightly). This is done by shifting and sprinkling outside a locked chamber.
If I interpret the pictures right, the height of the pile is one meter or so, right? That would be a good height for steering.

A young start-up I know here in Germany does it in a more technical way in a big container. But in principle they do the same within a shorter time. Just have a look at the container when you scroll through the pictures. Sorry there is no button for an english version:
finizio.de/pilotanlage/

The amazing thing is: they lift the temperature in the container, after they filled and locked it, up to 70 degrees Celsius within a few days just by an 80 watt fan which presses air through pipes on the floor. 80 Watt is nothing so they just have a little solar panel and remain off grid.

What is needed for this system is a check of heat and moisture. And some pipes on the floor to add oxygene ones a day or every second day, don't know yet. And one or two holes in the wall for the meters.
If you could raise the temperature within the chamber to at least 45-50 degrees for a longer time you could do a fine sanitization, I guess.

This would probably meet Jenna's remarks when you told us what works and what does not. And the advantage would be, as in the report was quoted, nobody has to touch the stuff before sanitization.  So you can take it to the fields or starting an ongoing compost process without fear to pollute others. Not even the rats would come in contact with the unprocessed faeces.

But first of all we would need to know the temperature and moisture during the process which is running now......

Waiting for a dispute,

Heiner ;-)
 
Heiner, the old farmer.....
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Dear Linda and others,

Thank you for sharing this report. Really interesting. Ascaris are definitely hard to get rid of. I did a lot of work during my PhD looking at what conditions do kill them. Simple storage (especially if open to atmosphere) had no effect on the eggs I was working with (at <10% moisture, they lived for >325 days at 20 degrees C). At pH 12.5, I had no reduction for >126 days at 20 degrees C. At 35 degrees C, without any ammonia, it still took 85 days for a 3 log reduction at a neutral pH (7.2). The two best ways to kill them were heat and/or ammonia (see page 44 of the attachment for more details). If you are going to store the material, would it be possible for the containers/bags to be sealed and to add urine? Fresh urine would have urea which would be converted to ammonia. In the sealed containers, the ammonia would remain and help to kill the Ascaris. 

Hope this helps and best of luck! 
Jenna
_____________________________________
Jenna Senecal, PhD.
Environmental Engineering Grp.
Swedish University of Agricultural Sciences
Research: blogg.slu.se/kretsloppsteknik/
Company: sanitation360.se

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  • Linda2019
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  • Dr Linda East is an Honorary Associate Professor in Health Sciences (Nottingham University, UK) and a Trustee of Dream Big Ghana Foundation (UK).
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Chris and Heiner, a huge thanks again for sharing such valuable advice. There is so much to think about and digest!  One of our volunteer trustees is currently undertaking a literature review to also add to the debate. In a month or so, we should have a decent review of the Dream Big Ghana programme as a whole with an action plan to take things forward. We will then share this plan in draft, and look forward to further debate and discussion. We cannot thank everyone enough for your contributions to date, which have been incredibly helpful given our rather low level of starting knowledge.  
With best wishes from all the team at Dream Big Ghana Foundation (UK) and Dream Big Ghana NGO (Dzita, Ghana)

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  • Heiner
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Dear Chris and others,

another very interesting post from the rainforest.... I learn a hell of a lot from your inputs!

You consider if a little micro enterprise would be able to finance the transport of the feces by the potential increased yield of their fruits. I doubt that because the product is more a soil healing one (increasing humus) than a yield driving one. But in combination with urine I could almost imagine that. This can be yield pushing from the first fruit. And your simple idea by using gravity via hose sounds very interesting to me because of the smell an the direkt contact with moist soils where the bacterias live which turn urea to ammonium and finally to nitrate. And when this all is leveled out and implemented, inclusive some new planted trees..... we should look after the backhold of water for the dry season at the same time. Nutrients and water make the music.... 

To stop the urease (?) we can choose to lower or to lift the PH value, right? If so we should see what material is easy to get, where ever we are in the world. But perhaps the ph value of the given arable land should play a little role too. If there is a low pH value in the soil (lets say lower than 5.5) a further decrease around the hose could cause a lack of nutrients for the plants we want to grow (P, Ca. Mg).

I had quite a few discussions withe farmers and organisations (organic..) about our topic during the last decades and it was pretty tough, to say it nicely. I hope very much that the progress, including the ecological and economical success, will start in the so called underdeveloped countries. Could be a part of a recovery of the whole ecological system which is definitely overused in many parts of the world. Therefore your experiences, Chris, is so valuable!

Heiner
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Dear Hajo, Linda, and everyone, 

According to the report, the local people seem to be accepting these UDDTs very well. I
have worked extensively with local people, including indigenous tribes here in
the Amazon, and they tend to be very practical persons who judge things based
on their senses. Everyone starts out with concern about the concept, but when
most local rural people see the finished compost, they realize that it is no
longer poop, since it no longer looks or smells like it. I also think that they
have a better understanding that nature transforms things than Western
city-dwellers, who tend to get stuck in the concept of “once poop, always
poop”, but nonetheless look the other way while raw sewage is dumped straight
into rivers that others drink from. If poop were always poop, that would mean
that we are gradually converting the whole planet into poop, which luckily is
not true. 

We have had the greatest acceptance among the Achuar people here, who are traditionally
fierce warriors. I always explain to them that defecating in the woods
liberates all these microscopic enemies, while with UDDTs we lock them up until
they are all dead, and they understand the comparison very well. 

I do not know how spread out these UDDTs are in Ghana or how practical this would be,
but, if we want to assure more hygienic management of this fecal compost, it
may be worthwhile to consider forming a microenterprise that empties these UDDT
chambers and uses it directly in agriculture. Optimally, the microenterprise
would make enough money from the sale of fruits and vegetables that it would
not need to charge any fees from the owners of the UDDTs. In this way, only the
members of the microenterprise would have to overcome their squeamishness and
learn to manage this ‘recycled soil’ hygienically. I would be glad to advise
them on this and meet with the users and the Ghana Team online. 

I invite DBG and anyone else who is interested to use and show our video on Managing Feces
in Sacks. (I also think there is no need to ask for permission, if videos are
publicly published on Youtube.) 

As stated in the report, urine holds by far most of the nutrients and should optimally be
used as a valuable agricultural fertilizer. It was not included in the survey,
but how many of the users are thought to collect their urine and carefully
apply it to their fields? If they do not want to deal with it, I would
recommend installing perforated and buried hoses 10 cm below the surface of the
soil among fruit trees and banana plants, such that it fertilizes the plants
automatically by gravity, as I demonstrated in the video I presented at the
Rich Earth Urine Reclamation Summit:
www.youtube.com/playlist?list=PLvBe4CpoH...tnDu9jKcCYCndIiTFRDA
The urine should hopefully not be wasted contaminating rivers or groundwater. 

If that microenterprise is formed, they may like to collect urine in addition to feces,
even though the volume of material to be transported would more than double. If
the toilets are uphill of the microenterprise’s farm and not too far away,
there could be a ’peepee pipeline’, in the form of a hose that drains the urine
by gravity. 

If the urine is stored in 20-liter jugs before use in the fields, it is important for
the hose to reach to the bottom of the jug, to avoid odors from going up the
hose toward the user of the toilet. I would also recommend applying one of
these 2 strategies for odor reduction:
(1) Adding material fermented with Lactic Acid Bacteria and sugary or starchy
food waste (maybe from rinsing plates before washing them with soap) before
collecting urine, to keep it too acidic for decomposition of urea into stinky
ammonia, like Nadia Andreev has demonstrated.
research.wur.nl/en/publications/lactic-a...-agricultural-applic
Does the local population in Ghana make an LAB-fermented drink anything like
Amazonian Chicha de Yuca (manioc beer, masato, cauim)? If there are solids that
are strained out, these could be put in the urine jugs to inoculate them.
en.wikipedia.org/wiki/Cauim
The local people may like to learn how to make sauerkraut and thereby preserve
their vegetables, improve their health, and produce enough sauerkraut juice for
managing their urine.
(2) Adding wood ash and/or powdered biochar before collecting urine to keep it
too alkaline for decomposition of urea into stinky ammonia.
pub.epsilon.slu.se/14601/1/Senecal_J_171003.pdf  (The stabilization without the dehydration.)
sanitation360.se/we-developed-a-simple-p...mErgCrIG7Hoe7Ue0Wn4M  (We may need to fill the whole jug with ash.)
pubmed.ncbi.nlm.nih.gov/19645508/  (Fertilizer value or urine with or without ash) I have yetto do either of these, but I encourage anyone who is interested to experiment with them, especially since they also improve the fertilizer value of urine.
Among other things, we would have to determine the quantities of these materials
that would need to be added.  

One place where the sacks of compost can be stored is simply under the users’ houses (separated
from the soil by sticks or stones), if they are built up on posts, since there
are no odors or flies. Another place is simply leaned against the UDDT itself,
on the side that receives the most sun, covered with a sheet of plastic or
billboard cloth to protect it against the rain and UV, but not sealed around
the sack, so water vapor can continue to evaporate out and oxygen can filter
in. 

Hajo, I am glad you also support the idea of doing ArborLoos, if the conditions permit
this. These have great advantages in terms of user acceptance, since the feces
never need to be manipulated, and in terms of cost, since they are smaller and
simpler. I even recommend not even putting a roof on the ArborLoo, to allow
for: more light, fresher air, cleansing with the rain, pathogen destruction by
solar UV, lower cost, and lighter weight. I also want to start building them
with urine diversion, to reduce: odor in the pit; nitrogen loss; and the
pushing of pathogens toward water wells.
I recommend these conditions for implementing ArborLoos:
--No flooding,
--Not finding the water table when digging the 1-meter-deep holes and hopefully
the water table is below 2 meters,
--There is a prudent distance from any water well that people drink from (16 meters?). 

Best wishes,
Chris
Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com
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  • Linda2019
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Dear Chris and Hajo -
A massive thank you for sharing your thoughts and ideas in the discussion here.  It is really helpful to see these different suggestions.  We have also been blessed with direct email responses in the past few months from other SuSanA experts (in particular Dr Elisabeth von Muench and Dr Tore Knos). We also had a wonderful video call with Hajo the other day, which give us so much contextual information. We have emailed with colleagues at the Stockholm Environmental Institute for a couple of years now, who always give us generous guidance.  So we are doing our homework and hopefully becoming a but more knowledgeable on this challenging topic rather than just taking Sanitation First's design as a 'given'... 

Chris, I have looked at your blog and found it really interesting, with lots of parallels to what we are trying to do in Ghana. I liked the two-part history of sanitation, especially the bit about Queen Victoria and her porcelain throne - that explains a lot.  There is a lot of information on your blog for us to study in depth. 

We  are currently working with the team in Ghana to complete a full review of our sanitation programme, to which the evaluation report under discussion here and our previous report on productive sanitation in schools are contributing. We feel we have some wonderful people to call on for advice now, so thank you and we will be in touch.

With best wishes,
Linda

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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

dear Chris, dear all,

I am happy seeing you contributing to this discussion as being a very knowledgeable practitioner of UDDT... :-)

I want to make a number of comments and additions to your long contribution and I hope our discussion will assist Linda and her DBG team in their project...  even where these are only our opinions and not yet international best practice which she looks for...
  • Firstly, I want to emphasize that we can have very different basic perceptions about UDDT use: you are a convinced user of the technology and you don't mind handling those bags and the material which comes out. From my experience in Africa, I guess that the Dzita population with whom DBG collaborates may see this quite differently and it will require a lot of training and awareness creation by DBG trying to convince them of the usefulness of the UDDT (reuse) technology.
  • I like the idea of using rice sacks in buckets (CBS) in cases where the number of users exceeds the capacity of the UDDT vaults for safe drying (minimum 6 months). Also I like the idea using the dried material as cover material during use of the UDDT. But as mentioned above, both will require the respective training. I hope that you agree if DBG may use your video for training purposes?
  • Because the current objective by DBG is improving the sanitation situation in Dzita, ArborLoos are a possible alternative. But we have to consider that Dzita is located right on the coast line and the maximum elevation is about 6 m above sea level. If the population uses shallow wells accessing shallow ground water, a safe distance between wells and toilets may not be ensured in this village setting.
  • The two links which you quote about the 'good side' of ascaris, I find very interesting. But we don't know at what stage the single person in Dzita is with regard to 'immunization' by ascaris, whether badly affected already of even being life-threatened.  In my view, the UDDT technology must not contribute to further spreading of infections and a treatment must be applied which ensures this, i.e. by heating the material to 500 for at least some hours, thereby destroying all pathogens. But since Linda is a health professional, she may decide which level of safety DBG should consider for the recommended sanitation technology.
  • I agree that the heat treatment of the dried faeces must avoid the destruction of the sacks by UV and some other approach as described by you must be developed for (probably decentralized) treatment of the bags. For sure the bags must be kept dry! My proposal assumed a 6 hours drying on a dry and sunny day at a confirmed temperature after which the pathogens should be destroyed at once.
  • I also agree with your concerns about the reliability of laboratory tests. But if we treat the dried faeces with heat as described, we don't require a test anymore, or? This link  on the forum discusses some of these aspects and one of the contributors (Dr Tore Knos) runs this website  containing related information.
I look forward to more discussions
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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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

Dear Linda and everyone, 

I had a quick look at your report. Congrats on your important work and achievements. 

Here are some suggestions for your UDDT operation:
--It is important that all of the users know that the filling of each chamber
should last at least 6 months, in order to give time for the contents of the
other chamber to decompose. With so many users on average at each toilet, there
is the risk that compost will be taken out too soon. If the number of users and
the amount of cover material allows this time to extend to a full year or longer,
this would allow for more piece of mind about pathogens.
--If this is a problem, new UDDTs should hopefully be built. Another option is
to switch to interchangeable containers. I use rice sacks lining plastic bins,
the bottoms of which are perforated to allow for drainage of any excess liquids
into the soil. When getting full, the sacks are tied shut, dated, and stored
elsewhere as long as one likes.
--The local dry soil can also be used as cover material, pure or mixed into the
sawdust and ash that are currently used.
--As I have mentioned on this Forum before, I use the final fecal compost as
cover material, after more than a year here in the Amazon, and it is the best
material for controlling odors and flies, while inoculating the new feces with
exactly the microbes that broke everything down in the previous cycle. This is
controversial for some people, but is less risky that spreading it on fields
and can help to encourage people to wash their hands, which they often tend to
forget.

--How big are the scoops? Usually one cup is enough, with another if there are
any odors or flies.
--There are many low-cost models on my bilingual blog, inodoroseco.blogspot.com
, where you can also see our practical model of TippyTap for handwashing.
--If the water table is deep enough, you may also like to consider implementing
ArborLoos (Wikipedia) to help more families and reduce the number of families
that have to share a UDDT. 

To join the conversation of recent days, I agree that we want to eliminate all of the
Ascaris eggs, but 3-4/g is very close to the goal of >1/g, considering that
each adult female Ascaris worm produces 200,000 eggs per day. Thus, these eggs
are not immortal and are dying off. Do you know how prevalent Ascaris is in
this population? 

We also need to put this into perspective, given that it is estimated that 1/6 of the world
human population has these Ascaris worms and most of these persons do not even
know they have them, since they are not life-threatening and mostly do not
cause outward symptoms, unless they are very numerous.
en.wikipedia.org/wiki/Ascaris_lumbricoides

Surprisingly, Ascaris worms even have a good side. There is a large and growing body of
research that supports the Hygiene Hypothesis, which states that contact with
germs and pathogens (including Ascaris), especially during early childhood,
helps people to properly develop their immune systems. The lack of this, with
children growing up in disinfected urban apartments, is apparently the cause
for the current pandemic of allergies, asthma, and inflammatory bowel disease.
It seems to me that it may be optimal to have a single Ascaris worm when a
child is one or two years old, to stimulate the immune system, and then
eliminate it.
en.wikipedia.org/wiki/Hygiene_hypothesis academic.oup.com/ibdjournal/article/15/1/128/4647656?login=true
www.tandfonline.com/doi/full/10.1080/1744666X.2018.1424543
 
Ascaris worms are also readily eliminated with Papaya seeds or with pharmaceutical chemicals (which may do collateral damage to the body). I often work in communities that lack sanitation and have had Ascaris worms a number of times and I kill them with Papaya seeds. I suspect that a single dose of 3 tablespoons of chewed seeds may be sufficient. Someone may like to do a thesis to determine the dose and deworming campaigns may be included in sanitation projects.
www.ncbi.nlm.nih.gov/pmc/articles/PMC6286506/ (Maize porridge with Papaya seeds.)
gooddecisions.com/foods/papaya-seeds/  
pubmed.ncbi.nlm.nih.gov/17472487/  

We talk about Ascaris eggs because they are the most resistant fecal pathogens and we
can identify them readily under the microscope, which we cannot do for the
bacterial and viral diseases that we are really worried about, like diarrhea,
cholera, typhoid, Covid-19, etc., because these organisms are too small to be
seen so clearly ... but apparently die off much earlier. Modern metagenomic studies could be done to track patients’
feces in actual UDDTs or in simulated conditions, but I have yet to hear of any
such studies. (Fecal samples could be placed in envelopes of plastic mesh that
are dropped into UDDTs, maybe with strings attached for periodically fishing
them back out for monitoring.) 

I highly value Hajo’s comments on this forum, but I do not agree with his suggestions in
this case, for the following reasons:
--Solar UV destroys the polypropylene of these sacks.
--To paint the sacks black would seal them against gas exchange, which is key
for water to evaporate out and oxygen to filter in.
--To expose these sacks to the sun would also expose them to the rain, unless
someone is watching them carefully or they are in a greenhouse… and we want the
material to dry out. 

If this were a centralized storage operation, a windowless shed of tin roofing painted
black would be an excellent solar oven (without UV destroying the sacks), but
the sacks are likely stored in a decentralized way at each house. In this case,
I would recommend leaning the sack against a wall that receives sun and leaning
a piece of tin roofing painted black on top. Another option may be to cover the
sack loosely with black plastic, which is not sealed and allows for gas
exchange on the sides. A further option would be to spread the compost thinly
on a sheet of plastic in a greenhouse for maybe a week, since UV also
apparently destroys these eggs, in addition to the heating and drying that
would take place. 

Another wild card is the often questionable reliability and ethics of laboratory tests for Ascaris
eggs, especially in developing countries and especially if they do not
regularly conduct these tests. I recommend participating with the lab, if
possible, to try to keep them honest. It is a patient search for the eggs that
look like beautiful golden sculptures. (More efficient and reliable lab methods
that avoid the use of hard-to-find, environmentally damaging chemicals should
also be worked out.) 

Good luck with this project and please let me know if I can be of any help. 

EDIT:
If there is still concern about Ascaris eggs after the additional 6 months of storage in sacks (hopefully protected against the sun and the rain) or if the users do not want to do the additional storage, this fecal compost could be put in the bottom of holes for tree (or banana) planting or in trenches within their gardens, where it gets covered by maybe 15 cm of soil and there will not be deep tilling for at least a year. Also, please remind everyone to wash their hands afterward.
Good luck with the project and future Ascaris testing.

Best wishes,
Chris Canaday
Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com
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Re: Household Ecosan toilets (UDDTs) in rural Ghana - and discussions about reuse opportunities and risks

dear Linda,

I agree that too little research is done into sustainable on-site sanitation technologies - whatever the reason may be for this lack of interest and/or funds. And that is the reason why you have a range of expert opinions. Their solutions are  mostly (and hopefully) based on professional observation and logic but lack the proof of scientific research thereby not creating best practice.

I was thinking how you can improve the safety of your material. You intend storing it in bags for another 6 months. From what I have read, I am not sure that the storage alone will help. What about using bags which have a small diameter, like rice bags (approx 45 cm)? These bags filled with dehydrated faeces from the ECOSAN/UDDT you store in the sun for 2 hours, turning them by 1200 deg then, just around midday.

I would guess that  3 x 2 hours in the Ghana sun will create at least 500 in the bag throughout, which you may enhance by painting the bags black. You can buy a 'chef's' thermometer which is used in the kitchen to check and ensure the right temperature in the middle of a roast in the oven. If you check the temperature in the centre of one bag at 3 points, the average will give you the approximate temperature of all bags if they are in the same location. Make sure the bags do not get wet, neither from top nor from bottom.

Personally I will feel more safe with the material heated like this then with a bag having been stored for 6 month (unless it is also exposed to sun by accident). From heat we know it kills ascaris, this has been researched. From storage we do not know how long is required.  Sorry, just again another opinion. But I hope for some good comments and contributions by other readers improving this 'technology'.

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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