Dear Robert,

I have been meaning to start a discussion on Terra Preta Sanitation (TPS), so maybe now is a good opportunity. Let me start by outing myself as a "TPS sceptic".
I find there is quite a bit of "hype" about TPS but very little hard and fast evidence that a "Terra Preta Toilet" is easy to use and well accepted. I assume that its direct counterpart would be a UDDT, thus a Terra Preta Toilet should be better than a UDDT (Ralf Otterpohl used to say the main advantage would be less odour but only if the lid is tightly closed).

One thing that annoys me a little bit is that the same "facts" about the "vast areas" with fertile terra preta soil in the Amazon area are repeated over and over again. Are people just copying from each other? Strangely, the same one or two photos of this type of soil in the Amazon is used time and time again in various papers... (and journalists just love it by the way: "ancient Indio knowledge is rediscovered to solve problems of today...")

There is an MSc thesis in the SuSanA library which includes information about the areas with terra preta soil, and it is actually only a small area that has that type of very fertile soil according to this research:

www.susana.org/lang-en/library?view=ccbk...mp;type=2&id=796
de Souza Cannavan, F. (2007). Diversidade das comunidades bacterianas em solos de terra preta antropogenica da Amazonia Central e Oriental (in Portuguese) - Diversity of the bacterial communities in Anthropogenic Black Earth from the Central and Oriental Amazon. MSc thesis, Universidade de Sao Paulo, Escola Superior de Agricultura, Brazil.

It is in Portuguese but some additional information in English was provided by Cecilia Carvalho Rodrigues:



Another question for me is: will the conference bring together those people that work on Terra Preta (without excreta) with those that work with Terra Preta Sanitation? I think that would be useful. The "terra preta compost" (without excreta) seems to be quite popular and maybe already a commercial success? See e.g. this website of a German manufacturer: terra-preta.de/ or palaterra.eu/. (although of course I can't tell if their product is a commercial success, only that their website looks very nice and professional).

I just can't see Terra Preta Sanitation work on a large scale (on a small scale with some enthousiasts it may work fine) - if we already have such difficulties with scaling up UDDTs, even though they are bound to be much easier to use than TPS-toilets where I have to add lactic acid bacteria/liquid, keep the lid completely closed etc.

I am looking forward to a debate or conversation with you and others on this topic.

Regards,
Elisabeth

Dear Elisabeth,

Thank you for bringing up the discssion! Terra Preata is antropogenic black soil consiting of organic matter including excreta and charcoal. It covers around 10% of the Amazon region around Manaus, not of all the vast Amazonian Rainforests. We can also call it Black Earth but why should all be in English? This is the inspiration of the probably most sucessful sanitation and biowaste management ever on Earth. In order to honour those Indios we use this name. We can say EcoSan just the same...

Now to TP sanitation. Please show me where the hype is? Hardly anybody works on this so far. The most promising process of lactofermentation is widely ignored. Desiccation does not make sense any more in many cases. In addition we want to compost urine so we do not need diversion any more, luckily. Urine application mimics chemical agriculture and is a dead end road.

For the process: The breakthrough solution to sanitation is lactic acid fermentation. It can be applied in most sanitation systems including pit latrines. It will require simple bacteria strains and simple waste sugars. Also urine storage and desiccation chambers can profit, even if the desiccation chamber ist not closed to he environment or at least covered toward the toilet(what is hygienically not acceptable). Our way of development is a closed container toilet, not diverting urine and pumping out once a week. Very similar to what EAWAG has developed with urine diversion. The logistics are feasible at very reasonable prices and we should forget about people in more densely populates areas dealing with their own excreta. Let us transport where excreta can be converted to Terra Preta or whaterver else to come to material for conditioning non-food land eg for re-forestation. The well proven fact of endocytosis, the direct uptake of living bacteia like E-coli and Salmonella into plants advises us against direct food production in excreta.

We work on systems that can easily serve 100.000 or a Million people also in more urban settings. No doubt that rural houses can have simple arbo loos with urine utilisation but this is not where the sanitation problem is. The TPS conference is to advance sanitation towards integrated solutions including Energy supply. For the first time we have the the beautiful sit-syuat-toilet that won the WTO-Design Award that I would install right away into my own house and that can work in multi storage, too (see www.terra-preta-sanitation.net). We invite especially also critical discussion, only this way we can learn. We need to create solutions for hundreds of millions of people. This is possible now.

Ralf

Dear Ralf and others,

terra preta sounds good, the multi level farming system (trees/shrubs/vegetables) is something that I am even trying to implement in my garden here in Northern Uganda (without trying to mimic terra preta, just found out about these advantages on my own). Something I have never understood about terra preta is the use of all that charcoal in the soil. Can you inform me about that?

Here, charcoal is the most common and preferred fuel for cooking - nobody would think of putting it into the soil, unless we are talking about leftovers from burning wood or chunks of charcoal. And the product of charcoal burning, the ash is also a known fertilizer and can be an ingredient in compost making. And, of course, a useful additive for UDDT toilets. So, why incomplete combustion rather than complete one (which is certainly giving more energy)?

And don't you think terra preta is predominantly something for moist climates? The Amazon region is known to be very wet - I think that helps with the development of humus in the soil. At very high temperatures and more dry conditions, humus has a tendency to degrade very quickly, so that deep humus layers will take a very long time to develop (decades rather than years). And here, I am just talking of up to 30 or 40 cm, not meters!

Cheers, Hanns-Andre

Dear all,

as this is my first post on the SuSanA forum I would like to introduce myself shortly. I am a young Brazilian environmental engineer, graduated at the Universidade Federal de Viçosa, one of the pioneer universities in Brazil in terms of soil and agricultural research. I have focused my studies in Permaculture and Ecological Sanitation and since my graduation I am based in Berlin. At the moment I am working as an upcycling artisan while applying for a post-graduation program in Germany.

From my point of view Terra Preta toilets are as important as UDDTs are. They should not be seen as competitors, but allies. I also don't see the need of having an air tight lid as an obstacle (also UDDTs have special conditions to work properly, like ventilation pipe and insolation). What I like about TPS toilets is that they try to create a better (and safer) soil conditioner as the one from UDDTs.
Only in Brazil there are more than 240 archeological sites where the Anthropogenic Dark Earth - ADE- (or Terra Preta Antropogênica - TPA -, in Portuguese) is being studied. They do cover a great area (ca. 20 000 km²), if one thinks that these spots were used mostly for food production. It is also interesting to say that such figures are only for ADE and they are not taking in consideration the Terra Mulata, which always surrounds the ADE and occurs on a bigger scale. Also these small percentages (0.1 to 0.3%) are just considering the already known spots. I think it is quite impressive to imagine a 100ha field (the area of the Estação Científica Ferreira Penna) that is still as fertile as 500 years ago and is nowadays known as one of the most fertile soils in the world!

As in Amazon Basin rocks or stones are not so common, the índios were forced to find alternative ways to chop down trees without using axes. They had specific ways to burn trees in order to obtain a glade. Based on that, it is easier to understand the char issue. Although it may look strange, cooking with woodgas stoves is high efficient and healthier than cooking with charcoal. And the good thing is that char has many many other properties that improve soil quality (one can find huge books only about that).

The TPS Conference is a good opportunity to discuss about a new theme and to show others a new way of sanitation and biowaste management. Hope to see you there!

Best regards,
Hugo

Hi Hugo,

thanks very much for the infos you have given about these terra preta soils. Could you give details about the benefits of charcoal in tropical soils, or references, preferably ones that can be looked up on the Internet? And do you seriously think the Indios were using something like wood gas stoves, or did they just have wood and charcoal in such abundance that they didn't have to worry about a little charcoal deposited in their land?

Here in northern Uganda, some people have little sieves with which they remove pieces of charcoal from the ash in order to reuse them. Charcoal is a commodity with a high value.

Thanks again, Hanns-Andre

Dear Elizabeth, dear all,
As regarding the distribution of terra preta, a map is given in chapter 4 of the book "Amazonian Dark Earths: origin, properties, management Ed by Lehmann et. al. 2003.
(api.ning.com/files/0ajZyv5b7ozZ3KKKbUV-R...E9nt3Upjf/09Kern.pdf
In my opinion, terra preta sanitation approach can improve the management of excreta in UDDT as sanitization time can be reduced and lactofermented faeces contain more nutrients and organic matter than simple dessicated faeces. The faeces can be lactofermented both during the collection stage (while in the toilet) and after it (in closed containers or earth pits). The amount of faeces in UDDT is quite small, but other types of bio-waste (such as cow manure, kitchen waste) can be added. As a separate toilet system, terra preta toilet is still in the course of elaboration we cannot say it is easily accepted or not simple because it was not yet tested except at the experimental stage. I do believe that in both cases - for UDDT system or terra preta toilet there is a need to change the attitude toward excreta management, we have to accept that we take care of our shit and as a reward we receive a valuable fertilizer.
In the experiments with terra preta in Moldova I used as bacterial innoculum sauerkraut and as charcoal I have used waste from charcoal which is produced for grill. Human faeces was the main component, but also have added cow manure, fruit waste and mollases (5-8%). I have observed beneficial effects on plants at 10 % of terra preta in pot experiments- for example even the germination was few days later than the control, the seedlings were stronger, there were more established plants and faster growth rate. During this year the effects of terra preta will be investigated in the field(the application was made during autumn). I think that terra preta conference would be a great opportunity to learn from all the research that was carried out until now in the field and share the experience.
Kind regards,
Nadia Andreev, PhD fellow Unesco IHE

Hi Hanns-Andre, hi all,

Regarding the question about the charcoal, it is impossible to answer without taking in consideration the cultural habits from the pre Columbian civilization. Some Brazilian tribes have different words to describe different types of ash (nowadays). The fire rituals vary a lot from tribe to tribe, being the Kayapós and the Machiguenga considered as the “masters of fire”. It is quite difficult for us to understand and/or explain their culture. In example, potteries were not seeing as simple objects: they were produced from different minerals for different uses. Some ethnics groups would even treat the clay pottery as a tribal member. So let me remark that TP soils are filled with pottery pieces and then it is possible to understand the importance that such groups were giving to these soils. The problem is that even the living tribes in Amazon don’t have the knowledge to reproduce TP soil.

As the creation of TP soil is unknown, we have to deal with hypotheses. I believe that small random glades were extended by means of fire, and such burnings produced a lot of charcoal (combustion of wet wooden mass). Then such glades were used for living purposes and became the known Terra Preta. After some time the Terra Mulata soils were created (on the surroundings) according to some waste management based on in-field burnings, maybe one form of slash and char. As no archeological artifacts are found in Terra Mulata soils, it is believed that such areas were used for agricultural purposes. I do think that biochar was a product of some agricultural management and it was not seen as something scarce.



I am no specialist at the topic, I am more like an enthusiastic . Most of the things I share about TP are based in readings from some Portuguese books from Embrapa and classes I attended during University. In English I would suggest the books and papers from J. Lehmann and W. Sombroek. In internet you can find some interesting basic/short information about Terra Preta and Biochar at www.css.cornell.edu/faculty/lehmann/rese...har/biocharmain.html
The website www.biochar.org contains also lots of information towards charcoal.

Hanns-Andre, please send me an email for more detailed conversation.. I fear we are starting a discussion more about terra preta and charcoal than about the Conference itself (the topic of this thread).
Dear Nadia, nice words and interesting study! Do you have more available details about it? Keep on doing the good work!

Kind regards,
Hugo

Hugo, thanks very much for these explanations and the very interesting links you have shared with us! As far as the charcoal issue is concerned, it seems to me that the main argument in our times is carbon sequestration in tropical (and other) soils. Apparently, char is much more resistant to degradation than other soil based carbon compounds (at least that's what the researchers are claiming). I think, with regard to the issue of climate change, that is a very valid argument, but the application of char can only be one aspect of carbon sequestration in soils. From that point of view, almost any kind of ecosan could qualify as 'terra preta'. So, what is the specific definition of terra preta sanitation? Is it the addition of charcoal that makes the difference? Or is it that lactobacterial process? And did the Indios ever use that process? - Of course, these are questions first of all to the organizers of the conference rather than Hugo.

Thanks again, and regards to everybody,

Hanns-Andre

An interesting note to the question - did ever the Indios applied lactic acid fermentation? From the literature data, the staple food of Amazonians was manioc (a carbohydrate rich plant), the bitter cultivars of which had high cyanogenic content. One of the processing techniques for detoxification was soaking of manioc tubers in water, during which lactic acid fermentation occurred. The manioc has also a short term storage capacity after its harvest; therefore, fermentation was an important practice to apply. Some inhabitants of upper and middle Amazon areas were fermenting manioc keeping it burrowed in earth pits lined with leaves for up to 1-2 years. Myers (2004) indicates that the ancient Amazonian population have used the practice of underground crop preservation in silos as well as different types of fermented food and beverages. For example cocoa was obtained via lactic acid fermentation. Some authors like Krieger, 2011 and Pieplow, 2010 indicate that lacto-fermentation was used by Amazonian population not only as a way to process and preserve food waste, but also to process excreta for the purpose of soil enrichment. For example, remnants of big ceramic vessels of 200-300 l discovered in some terra preta sites were presumably being used for fermentation of food waste and excreta. While there is insufficient evidence to prove about the application of lactic acid fermentation for excreta management in Ancient Amazonia, it still can be hypothesized that microbial rich waste was generated during their daily activities that might have been applied to soil or deposited to the middens that in turn have improved the decomposition process.

Hi Hanns-Andre,

the addition of biochar into the soil helps to keep the soil pH stable, increases the cation-exchange capacity (improving fertilization) and acts as a sponge holding the water at the soil upper layers. On the book "As Terras Pretas de ĺndio da Amazônia Sua Caracterização e Uso deste Conhecimento na Criação de Novas Áreas", Madari et al. (2009) write that the mineralization of black carbon in soil is stimulated by glucose addition and vice versa. So the combination of char and organic matter is the key to carbon sequestration, as char particles smaller than 2mm have a life-time of less than 100 years in subtropical soils (Birds et al. 1999). Other interesting aspect is that Pabst (1991) verified that the humus find at the Belterra Terra Preta (Belterra is a city on the North of Brazil) is six times more stable than the humus find at the surrounding Oxissoil.
If you haven't been there before, please visit this website. It has many interesting videos from the Hamburg University of Technology about Terra Preta Sanitation.

Regarding the manioc, there are two main types and only one have high toxic cyanogenic content. This one (M. esculenta) is still used on the production of flours and alcoholic beverage (through fermentation). The other one (M. utilissima) can be eaten with no poisonous effect after cooking on boiling water. It is difficult to assure that the índios used lacto fermentation on their waste, but it is known that they had knowledge about the fermentation process. From my point of view it is easier to fermentate than to compost (specially in temperate climate) and that is a good point on waste management. I think it would be also possible to recreate TP from well composted waste, but the composting process can demand a lot of work sometimes.

Kind regards,
Hugo

(Dear Hugo: you suggested to Hanns-André to move your discussion to e-mail. Please don't do that, as your discussion is indeed interesting for many people. Rather, I have re-arranged the threads. I have moved the part on the Terra Preta Conference in Hamburg to Events and to WG 5, and I have re-named this thread to match better what we discussed.)

Dear all,
It is good that we are having this conversation about Terra Preta Sanitation. I would like to go back to some points Ralf made:

Ralf said:


Ha-ha, isn't it funny to use a Portuguese term to "honor" the Indios (= (language of the conquerers)? For Brazilian people, I believe that Terra Preta sounds exactly the same as for English people Black Earth...

It covers around 10% of the Amazon region around Manaus, not of all the vast Amazonian Rainforests.

What is the significance of Manaus in particular? How can one then know if it is a big area (in the scheme of things) or not? If I am not wrong then Manaus is a city in the center of the Brazilian Amazon, the entire administrative region "Metropolitana de Manaus" has "101,474 km ²" (from Wikipedia), representing 1.5% of the Amazon (7 million km ² according to Wikipedia dt). Today, it has 2 million inhabitants (not for TP reasons but because free trade area, since large-scale computers and flat screens are built there at the expense of the environment).


To me it is quite a big hype. I say that because in plenty of news articles, it is mentioned (e.g. in that big Geo article from last year) - alongside other, more established technologies. Journalists love it and keep bringing it up as if it would save the world now (the "lost/rediscovered" knowledge of the Indios is saving our world now...). Also e.g. in the SSWM toolbox (www.sswm.info) it (terra preta toilets) is represented side by side the more established toilet types - as if it had already reached the same level of maturity. In my opinion, it is still at a research stage, far from being "proven" at any significant scale in practical applications.



I disagree that urine is a "bad fertiliser", there are plenty of results from countries where it has given them impressive boosts in yield. See the publications by SEI on that topic. See the work of SEI and IFAD in Niger for example (if anyone is interested in the Niger example: just put the name Dagerskog in the search field of the SuSanA library, or click here:
www.susana.org/library?search=dagerskog)
You would argue that these results are only in the short term and that in the longer term, the soil would degrade? Well, nobody recommends to only use urine. Of course it is always better to add as much organic matter (compost) as possible, too. But that doesn't diminish the importance of urine as a cheap, pathogen-free fertiliser, supplying N, P, K, S and other micronutrients.



I agree with that statement.



I disagree with this statement completely. Your statement should be taken as the opinion of one expert, but many other experts do disagree. I want to remind the readers that this discussion has already been debated on the forum previously, with very detailed postings by the Swedish expert Hakan Joensson for example (and a discussion on organic agriculture with detailed input from Gerhard Pelzer), see here:
forum.susana.org/forum/categories/17-fer...le-plants-preferably

Finally, let me pose another question, which I think is very important. You speak about Terra Preta Sanitation. Where is the evidence that this process of lacto-fermentation kills the pathogens to a significant degree (in particular the worm eggs)? If not, can it really be called sanitation. Shouldn't sanitation sanitise - at least to some degree (or at least "contain"). How exactly are the worm eggs dealt with in Terra Preta sanitation? Or is your argument that the worm eggs don't need to be killed if one does not use the compost for food production in any case (multi-barrier approach)?

I look forward to reading your replies and the replies of others, too, of course. I think we can all learn a lot here - even if in the end we might have to agree to disagree.

Kind regards,
Elisabeth

Thanks Elisabeth, for opening this discussion.

I admit I know little about terra preta sanitation, and have not cared to take a deeper look so far, because the whole issue had a esoteric touch for my taste. But perhaps this discussion may help changing this perception

Two questions/comments:

1) This lactic acid fermentation, is that the same thing as "effective microorganism" (EM) that are quite popular in parts of Asia and Latin America?

2) As I understand, the addition of charcoal to the toilet / soil is a central element of the concept. This is where I have the greatest doubts about the concept. In many regions, the use of charcoal for sanitation would be expensive (thus probably will not happen) and also very detrimental to the environment.
As has been pointed out before, charcoal is an important energy source in many poorer regions of this globe, using it in addtion for sanitation would thus be costly. Another important issue is that the use of charcoal as energy source is a huge problem in many regions of the world, as it causes deforestation and loss of biodiversity as wood from primary forests is often used for producing charcoal. This happens especially in regions where poor people are living. Promoting use of charcoal in sanitation would therefor exacerbate these problems.

Best, Florian

Hi,
Personally I think the terra preta concept is quite appealing with the aim of making a stable humus rich soil with excellent nutrient and water retention.

My main problem with the concept is that it is quite resource heavy. Composting needs a lot of woody/organic material to compensate for the nitrogen in urine and faeces, and in this case we also add charcoal. My estimation would be ~100 kg of wood to make ~20 kg of charcoal (would that be enough?) and 200 kg of wood for the composting - per person per year. And then you need to have (make or buy) the lactofermentation mixture + addition of sugars to feed them in the excreta mixture.

All this together makes it difficult to imagine an upscaling situation. 300 kg of woody material per person per year...woody biomass is not really available in huge quantities in most countries...I think Ralf's answer would be to grow bamboo with the greywater which could in turn be used for the composting, but I don't know how far that would take us.

The lactofermentation of feces seem quite good for sanitization though - Gina Itchon did some experiments in the Philippines with good inactivation of pathogens including ascaris:
www.drytoilet.org/dt2012/full_papers/5/Gina_S_Itchon.pdf

Then the question arises how much bacterial mix will be needed per person per year to sanitize the mixture? And how much sugars are needed to:
a) grow this amount of bacterial mix?
b) feed them once they are mixed into excreta?

I saw there was another interesting paper from Ralf's group at the dry toilet conference on lactofermenting excreta which showed best results with 10% wet-weight addition of lactofermenting bacteria, 10% wet-weight addition of molasses (to feed the bacteria) and 10% w/w biochar to the excreta mixture.
www.drytoilet.org/dt2012/full_papers/4/Asrat_Yemaneh.pdf

For a total human feces+urine prodcution of ~500 liters per year, the 10% wetweight would translate to ~50 liters of lactofermenting bacteria, ~50 liters of molasses and ~50 kg of biochar per person per year. What does this represent in terms of costs/resources? And that would be before the composting step.

To reduce the volume to treat (and the resources needed) it seems separate feces collection is still valuable, although this is not what most users want...

If both urine and feces are to be lactofermented with biochar + composted at scale our society would need to make TPS a top priority. Maybe the value of the terra preta will be so high that it covers the resources needed for processing? Is terra preta sold in Germany yet?

There seems to be a lot to research still, but I think it is cool that Ralf's group is taking on unconventional stuff.

Regards
Linus

Dear all,
I want to comment some of the statements by Ralf:

1) “Urine application mimics chemical agriculture and is a dead end road.” I do not at all agree with this. As a matter of fact it is quite the other way around!
Human and animal urine has been around during most of our evolution and the plants have adopted to it and been developed in such a way that they can utilize the easily available nutrients in the urine for rapid growth. Take for example spinach (Swiss Chard) which has been shown to yield about 7 times as much when fertilized with urine as when not fertilized. This is also the reason why ecosystems with plants and animals mixed, like grasslands and savannas can be very productive.

Then chemical fertilizers came along and chemical fertilizers mimic urine. Not the other way around! Savannas will be around for a very long time, if not turned into agricultural land or drying up due to climate change. Thus, I can not see that urine is a dead end road.

2)Chemical fertilizers have, by mimicking urine, made it possible feed our present world population of 7 billion, and not just 2 billion, which was its size 1927, just before chemical fertilizers started to be produced. The world population will continue to grow, and chemical fertilizers will continue to be important for feeding this population. Let us work together towards increasing its efficiency and decreasing its use of resources and negative environmental effects, by e.g. recycling as much urine and other fertilizer products from our sanitation systems as possible.

3) In temperate regions, as Sweden, the change in soil temperature is delayed in relation to the amount of sun light over the year. This means that even with a soil rich in humus, there is not at all sufficient concentrations easily available nitrogen in the soil in the spring, when the crops need it, which hampers the development and yield of the crop. In the autumn, when the soil is warm and the crop is ripening there is much nitrogen mineralized, in the form of ammonia (the same form as in stored urine), from the humus, but since the development of the crop was hampered already in the spring, there is not enough crop to take up the mineralize nitrogen and instead it leaches out, and for Sweden often ends up in the Baltic Sea. Furthermore, the low nitrogen supply in the spring means that our winter wheat ends up with a protein (protein is organic nitrogen) concentration that is too low for baking.

Therefore, Swedish ecological farmers in the 1990-ies initiated many urine diversion projects. The farmers wanted the urine so that they would be able to produce ecological wheat good enough for baking and at the same time minimize the leaching to the sea! But then we joined the EU and according to old fashioned EU rules, human sanitation products are not allowed as fertilizers.
The Swedish Association of Ecological Farmers still fight for being allowed to use urine though. For some 10 years, some ecological farmers have used urine through a possibility for exemption for household waste (urine is household waste) from the farm. This possiblity was removed by the EU about 3 years ago. Now the Swedish Association of Ecological Farmers are trying to be allowed to use urine for research purposes. So the Swedish Ecological Farmers certainly do not see fertilizing with urine as a dead end. Rather, they see it as a sustainable high quality (=far lower levels of heavy metals than in animal manure or in compost) fertilizer of biological origin.

4) We all agree that the hygiene of the food chain is very important and from this point of view, certainly urine and chemical fertilizers have a big advantage, as both are almost sterile when produced by healthy people. Furthermore, during the storage recommended by WHO (2006) urine sanitizes itself, without any use of external resources except the storage tank. Safe and well documented sanitation methods for faeces are heat treatment through hot composting (see WHO 2006 for requirements) or treatment by ammonia e.g. by addition of urea.

Lactic acid fermentation might also be efficient, but I have not so far read documentation on its efficiency against enteroccus, ascaris or viruses.

5)Waste sugars are used for the lactic acid fermentation. This is an important resource use, as many products with waste sugar, e.g. molasses, are excellent animal feeds and can also be fermented to bioethanol. Thus, I would like to see an environmental systems analysis showing that the use of waste sugar for lactic acid formation for use in sanitation systems is better than using it for feeding cows and gaining milk for undernourished children.

6) A sanitation system should be sustainable in its surrounding. It has to be locally adopted and with about 2.4 billion people without improved sanitation, we certainly need to be open to use all sanitation system, e.g. UDDT, vacuum toilet water separation systems, and Terra Preta, in the situations where they are fit!

Sustainable urine-yellow and faeces-brown regards,
Håkan

Not a Terra Preta expert, but I guess I can try and answer some of these questions:

@Florian:
1. The "EM" pit-latrine additives are as far as I know not the same, e.g. those are (if not a total "placebo") probably a by or waste product of microbial enzyme production to boost commercial biogas systems or other agro-chemical fermentation processes that need enzymatic breakdown of organic material.
Lactic acid fermentation is basically the same that is happening during the production of Sauerkraut. The lowering of the pH should kill most pathogenic bacterial, but cysts and worm eggs are probably only lightly effected I would guess (given that one of the main "features" of worm eggs is being able to withstand the very low pH conditions in our stomages).

2. I think the point of Terra Preta sanitation is to use the the high surface area of charcoal (similar to active carbon) as a sponge for nutrients. For that completely "degassed" charcoal is probably the best.
In the process of charcoal production one usually tries to minimize the buring-out/degassing of the volatile wooden components (mostly wood-alcohole e.g. methanole) as those provide the most heat, the remaining pure carbon skeleton only burns little.
However (as mentioned above) the very efficient wood-gas stoves that utilize the degassing process of fresh wood to burn of all the volatile subsatances in wood have mostly degassed and thus low burn value charcoal as a waste product, which could be very well used for Terra Preta sanitation. And those wood-gas stoves are recommended over regular charcoal stoves for health and efficiency reasons anyways (however charcoal is mostly used and sold to urban areas, where the main point is the ease of storage and transportation, thus wood-gas stoves have seen little take-up in these major charcoal using areas).

---
About Terra Preta being a hype of not... well I see it as a (little practically proven) additional tool in the sanitaton toolbox. Especially in very humid regions where the UDDT drying process does not properly work, if could be a very good way to make the reuse of fecal material quite a bit safer.
Edit: These very humid regions usually have plenty of wood for burning and waste sugars (fruit and/or sugarcane production waste) available too.

P.S.: I don't see why urine diversion could not be combined with Terra Preta if the users don't have problems with it. As written above Urine is a very good fertilizer, and the addition of so much nitrogen is not required for the lactic acid fermentation at all. And if poured on top of TP soil later on, the nutrient retaining properties should work the same more or less.
However as TP sanitation is ok with mixing urine and feces, it could be a way to avoid those "complicated" urine diversion toilets and simply go for (both gender) urinals to collect urine and not bother with the urine that goes into the TP latrine during "big sessions".

Dear all,

first of all, thanks a lot to Elisabeth for starting this discussion. As TPS is coming up here and there in one point or another, it's great that it is discussed here in the forum and all the pros and cons come together.

Linus, thanks as well for linking the pdf with the hygiene study on TPS in the Philippines. From the discussions on sanitation I followed in the last years, I would say, only if TPS can be proven to by hygienically safe for users and the product produced, there is the chance to get it out of its niche. Great that first results become available on this aspect! If there is already more out there, please let me know.

However, I have a question regarding this study. The study says, no Ascaris eggs were SEEN anymore after 60 days anymore. What does this mean? How were the samples and analyses undertaken?
As far as I know the problem with Ascaris is, that they become inactive but are very resistent. Do you know the reasons or do you have a hypothesis, why the Ascari eggs dissappeared and if the method was sound enough to guarantee this disappearance?
It would be great if other following this discussion can help me out. Maybe even Robert a Co-author or Ralf, who visited the project, can provide some more information.

Best regards,
Martina.

Hi everyone, interesting discussion. As far as I am concerned, Elisabeth hit on the critical point by asking about the pathogen load reduction from Terra Preta - that is the only factor by which we can assess the efficiency of any sanitation system.

I agree that the information about that is sparce, but then there are very mixed results from studies of UDDT and other similar technolgies. Helminths have been found in working composting systems well beyond the the usual storage times for most composting toilets.

I think we then have to consider a risk assessment proceedure, even though at present with limited information. When emptying any pit latrine, there is a significant risk of infection for those doing the emptying, given that without directly measuring pathogen loads in individual latrines, nobody actually knows for sure the level of the pathogens present. So even if the lactic acid fermentation has done nothing, I can't see that there could be any more significant risk from a terra preta system than a UDDT system.

However, the difference between the Terra Preta and the UDDT is that there are several other stages, including the mixing and co-composting of the material. Hence there is a multiple-barrer to infection, (at least potentially) several different ways that the sludge could be sanitised.

I do have to say that I'm disturbed by the lack of urine diversion, which appears to me to be unnecessary. The more liquid the sludge is, the more risk there is of microbial pathogen transfer, so one would think that using dry sludge would make more sense than mixed urine and faeces. I can't really see why you would want that.

Of course, the major drawback is the materials that are needed. Most composting toilets work (imperfectly) with additions of ash or sawdust, which can be obtained locally. These would have to have the lactic bacterial inoculations and readily available sources of biochar. Whilst it is possible to imagine people appreciating the value of charring woody materials (given that they should be able to cook on it at the same time), it seems to me to be a bit of a large step to assume that they're then going to see the value of it being used in sanitation, given that the charcoal they have made is clearly now a free source of extra energy.

The idea that some entrepreneur is going to set up a system for mass production of an isolated bacterial culture - and that the users are going to appreciate and afford to pay for production and distribution - seems quite far fetched to me. As Florian says, it smacks of EM, which is a highly disputed process with very little scientific evidence of efficacy. TP at least has the advantage of a major university research department behind it and properly peer reviewed science, though.

==

This weeks New Scientist magazine (issue 2904 16th Feb 2013) has a lengthy article on re-use of excreta, called 'Flushed with Success' by Fred Pearce. Focusing mainly on the benefits to farmers, it has some effective illustrations and might make NS readers think beyond 'flush and forget'.

Sanitation issues have been tackled by livestock farmers for as long as animals have been domesticated - the nutrients contained in the waste products are the only way of maintaining soil fertility for organic livestock farmers. And the stock population have to be kept healthy while the dung is re-used, so systems which minimise exposure to helminth challenge have been devised. Without hand washing! Varied and numerous soil organisms (incl fungi) can accomplish much of benefit, given half a chance. Any system which stimulates the soil biology should be taken seriously.

SusannahSoilet wrote:


Well that's true, but livestock farmers are also notorious incubators of disease. It seems to me that what is needed is solid microbiological science rather than romantic nescience.

Well that isn't really true. A farmer who is only relying on manure is not going to be maintaining the soil fertility as it cannot give all the nutrients that are needed. This is why organic farming systems do not rely solely on animal manure inputs.

Well again, that is kind-of true. But the idea that animals in livestock systems are not rife with infection is bunk, in my opinion. Also it is a mistake to imply that animals are affected by all human pathogens of concern or vice versa - helminths are a pathogen but are also supposed to be an indicator of the survival of other pathogens in the sludge that are more difficult to isolate and identify.

That depends on the science rather than just marketing! But yes, in general it is perfectly possible to sanitise sludge given the right conditions using soil microbiology.

Dear Linus,
Dear All,

your point on demand for resources like woody waste and charcoal are correct. We do also need a source of simple sugars, ideally from waste.

Why does it make sense?

Because good fertile soil is the most important resource on earth, water is following good soils. Improving soil must be the highest priority, else we kill hundreds og millions and we make climate change worse.

Therefore, woody waste should go into the soil! It is an important component of compost and it makes volume. It makes urine organic humus, too.

Charcoal: woodgas stoves are highly efficient, combat indoor pollution, produce charcoal with using LESS wood that most commonly used stoves.

Sugars: This is still a challenge, we should go for adding fruit waste, kitchen waste, spoilt fruit, spoiled bread (also absorbing moisture)

Sanitation problem solved, but only if we widen our view to teh more severe problems with the same projects. There are many variations, but lactic acid fermentation is the breakthrough.

Dear Hakan,
Dear All

some answers to your comments below. Be assured that I like you very much as a person even though i have quite different views. I am a strong promoter of organic farming!



Answer Ralf:
Comparing urine addition to no fertiliser is a nice show for naives. If you want to compare youo need to build living humus and compare urine with that. Mineral and sub-optimum organic production have around the same product yield.




Answer:
it is a questin of dosage, urine as a super fast mineral fertilizer should be added to woody compost to build humus. Plants prefer to feed on microbes and macromolecules, force-feeding with NPK makes plants ill and bad food.



Answer by Ralf:
Chemical fertilizers continue to ruin ouf future. Soils are dead after 25 years unless very fertile land stands misuse longer. We see this in many areas and organic farms are the only way towards a future for many. Building soil requires comittment and knowledge, but the product yield dcan be the same up to a lot more (see
) Instead of being sucked by partly criminal agro-monster companies organic farmers can earn money and hand over good land to their children one day, with balaced food production. Global reports are very very clear.



Answer by Ralf:
Also Scandinavia has great and productive organic farms. Plants PREFER organic feeding.




Answ:
This is an important point that also concerns me! We can probably use the stuzff that is spoilt and not useable any more as fodder. At the same time we make excellent organic fertiliser out of the waste sugar, maybe the whole chain is not too bad...



Answer:
UDDT can be a god option but we should also add a lacto-bacteria mix. They smell too often, even if it is very little this can be improved with very small amounts.


OK, with "let us build soils with plenty of living humus - and keep feeding it!" regards
Ralf

Dear Martina,
Dear All,

Lactic Acid fermentation is firt and formeost to supress smell and to allow container / tanc collection of excreta without or with UD.

Sanitisation is a very welcome "side effect", but only with going down to pH 4 we have a strong influnce. This can not always be reached and requires lots of sugar waste, however odor avoidance does work even up to pH 7.

I recommend 10 years non-food for all stuff from toilets, for helmith eggs, pharmaceutical residues, synthetic hormines. All this will be soved to a large extent by time, unfortunately by washing out to groundwater for the micro pollutants.

Sanitisation is a lot more serious than we belived, by the clear fact that plants "eat" even e-coli and salmonella (see Plos One: Turning the Table, Endocytosis) makes it impossible to have a short cycle.

Ralf

Otterpohl wrote:


Ralf, thanks for this, which I consider to be not only extremely good advice but something that can/should change the language of ecosan.

I think this is the paper you are talking about above. Remarkable stuff, is there any indication that the pathogens taken up in plants are viable as sources of infection?

Hi Martina! Sorry it took a long time to answer to your query about terra preta sanitation. I (Dr Gina S Itchon) was the principal author of the paper from the Philippines. We undertook the study on terra preta principally because we wanted to find out if the process of lacto-fermentation will be able to get rid of or minimize the number of Ascaris lumbricoides eggs which in an earlier study proved to be very resistant to drying. After 60 days, we reported in the paper that there were no more Ascaris eggs seen, or none seen. This is the way helminth eggs in feces are reported. We do not presume that they are completely gone but we could not see any in the samples taken after 60 days. Admittedly, more studies need to be undertaken and up to the present time, I remain very hesitant about re-using human feces for agricultural use because in my country Ascaris infestation is a public health problem with infection rates going up to 80% of the population in certain places. Pathogenic bacteria are not a problem since bacteria die very quickly if their environment is changed. As of the present time, I understand that our study remains the only one about the hygiene aspect of TPS. If there are other studies similar to our study, I would certainly like to be informed about them.

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

Note by moderator (EvM): I have created a separate new thread to discuss how to measure helminth eggs in a reuse context, please see here:
forum.susana.org/forum/categories/17-fer...s-in-a-reuse-context

And back to the topic of Terra Preta Sanitation...

I have to say that my doubts towards this concept have not really dissipated from the discussion so far. At best it sounds like an interesting vision, but currently way too complicated and with too many questionsmarks attached to be something that I can apply in projects to solve problems.

Florian

There is one study undertaken in 2010 by Scheinemann & Krüger at the Institute of Bacteriology and Mycology at the Veterinary Clinics, Leipzig

The authors, indicate that there was a decrease of rate of embrionation of Ascaris eggs from 96% to 0% (8 week of lacto-fermentation) in two investigated matrices of cattle manure with charcoal/no effective microorganisms and with charcoal/with effective microorganisms. It is considered that the main factor leading to the reduction of embrionation rate of Ascaris was maintaining of increased temperature during fermentation, that of 36 ℃.
Kind regards,
Nadia Andreev

Dear all,

This is my first post here in the forum, although I have been following the discussions for some time. Shortly introducing myself, I am Brazilian and have just finished my PhD working with ecological sanitation, especially with faeces and urine treatment technologies.

I have worked for some years with ascaris and I see the methodological aspects of evaluating them as of a big concern. I will also look into the specific topic about that here in the forum.

The paper that presents the ascaris eggs monitoring of Dr. Gina, I find it extremely important, but it is not common that the eggs disappear from the faecal material, they just become unviable, which is the no capacity of developing into the larvae stage. They do can degrade and then disappear, but after some months of being inactivated (what can take another several months…). They can be fast degraded just if they are submitted to really strong treatments, as high temperature and pressure, which is not the case of TPS.

I think that the factors that can act against ascaris on TPS should be identified and then studied. The methodology of extracting and evaluating the eggs should also be clear, and it is also recommended to work with high quantity of eggs per gram, so you can actually see 2-4 log units decrease, and have a more consistent data. I know it is not the easiest research, so congratulations for what you have done so far!

Kind regards,

Maria Elisa

Thanks, that is very interesting. Do I understand you to mean that the ova can disappear but still be active?

Can you help us understand how and when we should interpret reported Ascaris figures? We are discussing that here.

Dear Gina, dear Ralf,

thanks for the response and additional informations. Sorry for responding late (somehow I didn't see your entries at earlier visits).

Ralf, your information that the stuff should not be used for at least 10 years turns the whole discussion. I always read it having in mind that a reuse is anticipated as early as possible - therefore my considerations regarding hygiene. And this is how I understood TPS until now, having in mind pilotes of Haiko Pieplow and others.
If we follow your thoughts the focus has to change completely. Then hygiene is a minor aspect but logistics (storage space) and economics come into the focus. Did you (as well as others) do research within this aspect? Can this be economical or competitive with other systems? (Not considering that sanitation always costs and there exists a right for sanitation for each human being.)

Looking forward what the discussion brings regarding this aspect,
yours, Martina.

Dear all, dear Martina,

your point about Ralf's information is very interesting. As I understand it, this 10 years are regarding the use of the soil and not its storage time. So the soil should not be used for food production for minimal 10 years, but could be used for non-edible plants production. And then, after ten years one could use it for edible plants. As you said, the reuse is still very antecipated, only not for food production.
One interessant point would be to create a soil conditioner using the whole idea of TPS but without human excreta (similar to a Bokashi bucket) and use this soil for food crops while the one from TPS toilets could be used for timber production for example.

Kind regards,
Hugo

Dear Hugo,

thanks for the clarification as I wasn't precise enough in my statement. Of course, you are right. The soil can be used for non-edible food production or landscaping.
However (therefore I didn't consider this), it will be very hard to control this. If you have a fertile product, how can you avoid people using it for food production for ten (!) years. Most agricultural control systems are not able to provide such supervision - especially as in many countries no consistent data exists on the plots, their owners etc. and when it exists it's hard to get it.

Therefore, I concluded that you have to store it. Although there are potentially some other options available.

Yours, Martina.

Dear Florian,

I agree with your points. In our experience, it cannot be considered as hygienically safe to store faecal matter from UDDT for 2 years. We recommend post-composting with other organic matter but it is difficult to ensure the required temperature in the compost heaps.
Therefore terra preta treatment might be a good alternative to composting if it removes pathogens at lower temperature in a shorter time.
We are starting to combine UDDT and post-Terra preta-treatment (of faecal matter and urine) in this way and can hopefully present some results soon.

Best regards
Claudia Wendland
www.sanitation.wecf.eu

In my opinion, it is difficult to imagine a sanitation approach which works at household level. Most people don't want to even talk about human excreta, imagine about handling it! So the toilet user should not have any type of contact with the excreta. In this case, the ideal sanitation should be provided by the municipality with off-site treatment. This can create the possibility for the municipality to take proper care of the risky soil, training proper personal for handling and also deciding secure places to dipose it. That occurs also with sludge from conventional sewage treatment plants in many countries (the toilet user has then no access to the end product).
From my point of view, soil conditioners obtained through treatment of human feces (or feces and urine) should not be used as amendment for food production (in large scale). People produce biowaste enough that can be used to make safe soil conditioner for food production (and that can easily be done at household level!).

If a family has no municipality support and are willing to manage its own excreta at household level in order to improve the land and its health, why not starting it by managing the kitchen waste? In my opnion that is a "safe way" to produce fertile soils for edible plants.

Using the TPS process (fermentation+vermicosposting) for kitchen waste would work fine, as there is no sugar supplement needed and is far easier than composting. So the produced soil should be as fertile as the one from the toilet, right? Then the family can grow vegetables with safe soils and non-edible plants with the "risky" soil from toilet having in mind the multi-barrier approach.

kind regards

Dear Ralf and List,
I appreciate all of the thoughtful discussion points made on this very important topic, and proposing the innovative strategy that is TPS for addressing many important urgent issues facing humanity: closing nutrient loops, building soil while sequestering atmospheric carbon and enhancing food security, restoring water quality and biodiversity.

In regard to your post #3576 the PLOS article regarding Turning the Table with plant endocytosis, I am confused regarding your statement “impossible to have a short cycle”. From my interpretation in the General Considerations section: a) the plant does use energy to take up the bacteria but “justified by the benefit of using microbes as a nutrient source” i.e. by catabolism. b) “ We show that the presence of microbes induces the expression of plant enzymes with divergent functions, such as cellulases and cellulose synthases, and this suggests that the uptake process consist of a succession of distinct and tightly regulated processes, which would exclude the possibility of permanent induction of genes.” To me, it seems that this paper does not imply that the plants can take up pathogens and pass them on up the food chain, but rather digest microbes for energy and nutrients to support anabolic processes. Can you direct me to what I am missing?

To offer up some more evidence how microaerobic composting, which includes acid fermentation, can destroy many stubborn pathogens, specifically Ascaris eggs, here are a couple of interconnected open-source papers which offer some comfort:
1. Turnover of Carbohydrate-Rich Vegetal Matter During Microaerobic Composting and After Amendment in Soil Appl Biochem Biotechnol. 2011 September; 165(1): 270–278. This demonstrates that acid fermentation, a process of microaerobic composting, does indeed primarily produce volatile organic acids (VOAs) : acetic, propanoic, butyric, isovaleric, valeric, and caproic acid. It is the presence of these VOAs i.e. short chain fatty acids that inactivate Ascaris reproduction. Additionally, such treatment renders more carbon available to the soil food web and immediately avoids off gassing to atmosphere as CO2 as compared to aerobic decomposition in this experiment.
2. Inactivation of Ascaris suum by Short-Chain Fatty Acids APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Jan. 2011, p. 363–366

Because public safety is paramount, would like to point to a couple of sources of information regarding simple water tests for E. coli that can be adapted for compost (by suspending in water) and conducted in remote regions. If there is any doubt, testing is warranted.

1. David Omick’s technique also link to well-organized information on barrel composting which could be adapted to TPS.
2. Agua Pura Para El Pueblo has posted worksheets on their similar simple water tests

No doubt that the earth’s forests require reprieve rather than further exploitation by charcoal production. There is much promising research being conducted on the utilization of the vast amounts of agricultural biomass into the residential clean cookstove campaign: transitioning to rice hulls, rice and wheat straw, corn stover, coffee bean husks, bagasse, the shells of nuts, pine needles, perennial weeds, orchard pruning, coppicing, etc.. The gasification and biochar documentation from Dr. Paul Olivier offers some valuable information, to begin. In essence, integrating simple Top-Lit Updraft (TLUD) cookstove design fueled by agriwaste and fabricated locally, stimulates local economy by processing fuel, fabricating stoves, conserves traditional cooking fuel (replaces wood or propane), reduces emissions, and creates biochar which could be integrated into TPS systems, or distribution of value added products.
To me, TPS , though in its relative infancy, offers an ingenious tool in the “restorative systems” toolbox and potentially offers a future of abundance as further optimization occurs in particular urban permaculture and agroecological designs.
Kind regards,
Jeff

Ok, maybe it is a bit off-topic but there is an alternative interesting take on the idea of acidic fecal sludge treatment and soil supplements with biochar:

Wood "vinegar", especially bamboo "vinegar" (a potential side product of charcoal production) is a known antibacterial and antifungal substance already used for composting of pig-manure in china and other places where the production of this useful liquid has a long tradition.

It would seem to me that the use of this "vinegar" in composting would be probably in effect very similar to the "terra preta" method, and that it is actually derived from charcoal production makes it a perfect fit.
It also solves the issues of sourcing and managing the lactic-acid bacteria suspension by replacing it with an easy to handle and potentially 3rd party produced substance.
In addition, bamboo cultivation and charcoal burning is a common and economically viable praxis with many beneficial side effects.

Here is are two manuals on easy construction of such small scale charcoal kilns with bamboo vinegar capturing:
c.ymcdn.com/sites/www.echocommunity.org/...ontal_Drum_Kilns.pdf
interscience.in/IJARME_Vol2Iss2/14.pdf

Other related interesting reads:
www.ncbi.nlm.nih.gov/pubmed/20060567
www.wpi.edu/Pubs/E-project/Available/E-p...Vinegar_Brochure.pdf

But there is actually much more information on this (do a Google search).

We might do a trail for this with two of our members in western Uganda (Rwenzori mountains, a natural habitat of Bamboo), but if anyone is interested in contributing (or funding practical research) please contact me.

This document has even more details about wood vinegar, which is supposed to have beneficial effects on composting and also odor reducing properties when applied to manure.
Now, I have to say to all sounds a bit like a "wonder" solution, so I am a bit skeptical to be honest... but at least here in Uganda a LOT of charcoal is produced and AFAIK none of that wood vinegar captured. So if it even has a slightly beneficial use and can be an economic incentive to improve the (very inefficient) traditional charcoal kilns it could be a huge benefit overall.