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Terra Preta Sanitation Part 1: Overview
Hello, my name is Ralf Otterpohl. I'm director of the Institute of Waste Water Management
in Hamburg University of Technology. We're presenting Terra Preta Sanitation and this
series of videos is made as a student project by Andreas Swensson. We hope you get an overview
on our work on protecting water and recovering nutrients at the same time. This is based
on a completely new toilet system that is part of an integrated sanitation approach
that links sanitation and agriculture.
In our natural and sustainable environment, we get our drinking water from clean surface
waters like rivers and lakes and also ground water. The ground water sources are refilled
by rain, which is retained by the humus rich soil layer and leaking into the ground. Our
food is produced by crops. They are growing well in the fertile soil, which holds much
water like a sponge. Due to the nutrients in the humus rich soil, our food is healthy
and supplies us with everything we need to survive. After the consumption, almost all
nutrients leave our body again – in our excretions: faeces and urine. But when we
are sick, our faeces also contain dangerous pathogens. Biological processes by microorganisms
living in the soil layer consum and destroy the pathogens. Our droppings are sanitized
and transformed to nutritious humus. This way the nutrients we took out of the soil
by harvesting the crops are brought back. They can be used for example by trees, which
later give back the nutrients to the soil again – by dropping leaves, branches or
dying off, and so on. After some time also our crops get access to the nutrients in the
soil again and produce our healthy food. The circulation of the nutrients is closed. And
the fresh water is not affected and stays clean.
But the current situation is often different and not sustainable. The nutrient circle is
interrupted, because we don't give back the nutrient sources to the soil. The soil depletes.
And the humus layer decreases. So, the soil looses much of its water holding capacity.
This worsens the conditions for the plants even more. To grow crops on the dry and depleted
soil, a lot of irrigation is needed, and often artificial fertilizers are used to add nutrients.
But despite all the efforts, the yield is much lower than using rich and spongy soil.
Now, that the soil has lost much of its capacity to retain water, less rain is soaked up into
the ground. And so the surface run off is increased. This brings soil erosion and flooding
with it. There is also more evaporation. The ground water is not refilled any more, and
its level sinks. The reduced vegetation as a result of the bad soil, even has an effect
on the local climate, which accelerates the desertification. These
are the effects on the agriculture, due to the interruption of the nutrient circle. But
where do the nutrients go, if we don't give them back to the soil and the plants?
They go down the toilet, in the true sense of the word. We direct the nutrients into
the fresh water, either indirectly by leaching from pit latrines or leakages in septic tanks
into the ground water sources, or, as a matter of fact, directly into the rivers by outlets.
For the transportation of the urine and feaces in the sewerage system alone a lot of fresh
water is needed and also contaminated by the wastes. Mostly, the waste water is not even
treated to reduce the organic material before it is discharged into surface waters. With
the nutrients also the pathogens from our faeces are brought into the fresh water. This
way, not only the balance of the ecosystem in the river is endangered by the enormous
amount of nutrients, but also our own health, as we drink the water, that contains the pathogens.
In this vicious circle deseases spread.
Well, we are dealing with new ways of sanitation to find sanitation systems for those people
in the world, who don't have adequate sanitation so far. So, we are talking about around 2,000
000 000 people. One of the most promising developments in sanitation is what we call
"Terra Preta Sanitation". Terra Preta is the black soil, man-made black soil, that has
been discovered in the Amazon, and that was made by composting organic matter, but also
excreta, in a form of adding charcoal and some *** material. And this has produced
a highly fertile soil, and this is called "Terra Preta". Terra Preta Sanitation is a
system, where we collect excreta under lactic acid fermentation to avoid smell, and to have
a very good sanitation. After the collection and the transport to a composting site, charcoal
is added, and the composting process leads to large amounts of rich compost.
Now, let’s compare the two different systems of dealing with nutrients and water 70 to
see how Terra Preta Sanitation can be implemented. The problematical system of leading nutrients
into the fresh water, is displayed in red colour on the left. The sustainable system
of a closed nutrient circle, is displayed in green colour on the right. In the system
on the left the nutrients from our faeces are causing pollution of fresh water – whereas
in the system on the right they are used for the reproduction of humus soil. The result
of the left system is soil depletion which leads to a decreasing agricultural production.
The right system improves the soil, ensuring the possibility for a longterm highly productive
organic farming. As shown, valuable nutrients are changed into pollution and waste water
by the use of flush toilets and pit latrines.
On the campus, all toilets are flush toilets. So, flush toilets: if it's not flushed, it's
going to be pretty bad and you can't accommodate it. Any shortage in electricity or a disruption
- the pump is not working. Clearly, there are shortages; shortages and complaints. The
toilets can't get 24 hour water service. And water is basic for the toilets. We are exposed
to bad smells due to lack of water. The social aspects of sanitation are crucial.
One hand is the availability of toilets: it's against human dignity if people don't have
good toilets at their disposal. So, that's a social discrimination through our world
society, that has enormous amounts of money available, and with a very tiny fraction of
that, this whole sanitation problem could be solved in maybe ten years time. Our societies
are simply accepting, that 2,000,000,000 people in the world are having no toilets at all
or nasty toilets, that are a danger to public health, children are dying from that - people
simply don't look at that. You can see the toilet that 8 households are
using, for each household you can count more than 5 to 6 individuals. So, more than 48
people are using this toilet. (It's surprising to see this one as a slab, you know. Just
as a slab.) If you look closer, you can see maggots. (...) They add ash, to control the
maggots and the smell. We have a sanitation problem here.
There is a lake near to us, which is full of aquatics, especially fishes and crocodiles.
Due to the sanitation problem, automatically everything is going to the lake. Nowadays,
the chemical concentration in both lakes is very amazing. Every day we are loosing our
natural resources. Both lakes are now endangered.
The polluted water, containing pathogens, leads to deseases. To compensate the missing
nutrients in the soil, artificial fertilizer is used. But it cannot replace natural humus
and so it cannot stop soil depletion. There is evidence that it even worsens the sitiuation.
The more the depletion is progressed, the more fertilizer is needed to keep on farming.
And so, it leads to dependency on the fertilizer. It just delays the symptoms of the nutrient
deficiency due to an agriculture which is not sustainable.
Traditionally, composting and recycling excreta to the soil was the normal thing to do. So,
it was the natural thing, however, not always done in a good way, especially with sanitation
- just putting excreta into soil is not a good practice. Then, when it was made possible
through chemical technology, to process nitrogen or produce commercial fertilizers, the whole
process of composting was overrun by very cheap materials, that made people lazy, so
they didn't care for composting anymore. They just bought the fertilizer.
Especially in a place with a soil depleted area, farmers can't afford to buy fertilizer,
because it's expensive. The farmers use artificial fertilizer every year. They are dependend
on the artificial fertilizer. But when they make their natural compost, there is no dependency
upon that. We see a lot of soil degredation, that is
following this type of chemical agriculture, because this can be done for a couple of decades,
but then the soil is getting worse. This chemical, especially artificial fertilizers, have some
impact on the soil. The application of chemical fertilizers, and also pesticides, tends to
kill the earth worms, and the earth life. Even if one increases the production for a
while, there is a problem with the soil because of the chemical content in the artificial
fertilizer. The absorption capacity for water is getting less, and erosion is getting worse.
Already now, many farms go out of operation, the yield is going down. The problem of the
country is the annually decreasing production. And so, there is a movement towards organic
agriculture. The number of farms doing organic agriculture is growing very fast.
The rising demand of fertilizer leads directly to rising prices. Both the increasing prices
for fertilizers and the farmers bad health condition culminate in an economical weakening
of the farm. This way, these side effects also contribute to an increasing production.
A vicious circle is created, making worse the circumstances. Now, considering all this,
how can we convert from the problematical system to the sustainable
one? Let’s get into the details of Terra Preta Sanitation as a sustainable way of sanitation,
soil improvement and water protection at the same time.
So now, what has to be done to switch from pollution to production? How can we change
from soil depletion to soil production? If we want to use a long-lasting, highly fertile
Terra Preta soil, instead of producing chemical fertilizers? Basically, two things have to
be done: We should get away from common pit latrines, or flush toilets, and come to Terra
Preta Sanitation, that is producing soil. In addition, we have to move away from the
inefficient burning of wood in normal stoves, and go to woodgas stoves, that are producing
charcoal.
Terra Preta Sanitation starts with a special collectiona toilet. The Terra Preta toilet
plays the key role in the whole system. Now, we want to make sanitation, that produces
Terra Preta soils, and for that we need toilets, that are capable of collecting excreta without
a lot of dilution. We have now started a development, that is based on finding a container toilet,
that is collecting all the excreta. Now, how can such toilets look like? We have found,
that the camping toilets, that are on the market, are coming relatively close to what
we need. Unfortunately, they are still a little bit to small, so they are not suitable for
sanitation installations for households. They are putting toxic chemicals in the toilet
and then they flush. That's the normal operation. With that we have to much dilution, so we
must not flush. But we can use this type of toilet, because it opens with a little handle.
So, when we want to use the toilet, we just open this hole here. For making this smell-free,
we add some lactic acid bacteria into the toilet, before we use it. The bacteria will
convert the excreta into something that doesn't smell anymore. And also, there is no gas formation.
The material is air-tight. Toilets are always a tricky issue, of course.
It must be really clean and smell-free. Normally, there would be only a little dirt. And when
people clean the toilet, they should use a sprayer or a little shower. With that, the
toilet can be used with very little water. So that we don't have a lot of dilution. So
that the tanks are not getting too big. A good option to finding sanitation systems
that are comfortable, cheap, and also applicable in different situations. All in all, the process
works out nicely. Now the challenge is to delevop a larger toilet, so that it can hold
the excreta of a family for at least a week or maybe even a month.
At the moment, we are developing special toilet systems, and these toilets are performing
lactic acid fermentation. This process is meant to avoid smell, and to kill pathogens.
We put excreta lactic acid fermentation. That is a process, where the pH-value falls to
around 4. That is a very thorough sanitisation. Most of the pathogens should be reduced. You
have less handling of the excreta. That's an important aspect. Excreta contain very
persistent pathogens, which are difficult to eradicate. But we will achieve that as
well. We have done experiments with this since 1,5 year here at Hamburg University of Technology.
It does work very well. Which materials have do be added? Normally in human excreta, there
is not much sugar, but the lactic acid fermentation is based on sugar. So we need to supplement
the process with sugar. Which amount of sugar do we need to add? That is one of the things,
we are looking at. We have advanced in this, we know the Ins and Outs, we have identified
3 to 4 lactic acid bacteria species, that are ideal. Without any extra energy source,
it is a natural process. As I said, you need to add a bit of sugar, but I think, that's
easy to manage.
After the lactic acid fermentation, we compost. For the composting, that is similar to normal
composting, we add charcoal. With that we have a thermophilic composting, after that
vermicomposting. We still have very little compost from sanitation. Excreta are mostly
lead to the water cicle, causing a lot of problems: killing many people trough the pathogens,
that are then in surface or ground water. If that could be converted to compost, we
could help protecting the water and improving the soil quality at the same time.
If people would really use compost, this would give a guarantee for the soil. We tried to
introduce the compost to the farmers, and the farmers experience it and they get a high
yield because of the compost. Using this wastes, feaces and urine, converted to compost is
very essential. What we see here, is the composting site of
the University of Arba Minch. This is the first compost heap, we set up 2 weeks ago,
which is mixed now, to keep the process going, to improve the aeration. The structure is
untied. It's a chinese method that is suitable for composting feaces, because it reaches
very high temperatures. It's done by mixing organic waste from kitchens or food left-overs
with grass and some cow dung or human feaces. Then the heap is build up with the mixture,
and in this heap we stick bamboo sticks, which will be taken out after 1 day. So there will
be aeration holes. And before taking out, the heap will be covered with mud to keep
its temperature and moisture. After two weeks, then the heap will be mixed to another one
and left for another 6 weeks. And then the composting process is finished normally if
everything goes well. All waste material which is collected from
farm residue and household residue we can collect which are special plant bio mass parts.
To enhance the composition, we put together urine, feaces, ash and some soil.
We started as a trial here last year, this year it is finished. So we want to use this
as a nursery fertilizer. To get the Terra Preta, you need to put microorganisms
in the charcoal. But a freshly produced char with a high temperature is sterile. There
is no life in it. To have the effect, Terra Preta effect as soon as possible, you need
some efficient ways to introduce the microorganisms in the char. There are some people they are
doing different anaerobic biological processings, like digesting or lactic acid fermantation.
And I'm working with composting. I just add some char to the composting process. We have
a lot of microorganisms that can fast enter the char and cultivate it.In composting, you
can take fresh matter with lower energetic value, like leaves or grass.
Having a toilet using worms to compost the faecal matter, there are good results, especially
with respect to transforming it to humus. But one of the challenges is the odour problem
from the toilet. That's why we are using vermicomposting as a further stabilizing phase. Because...
It's also found to be efficient in hygienizing the faecal matter, even vermicomposting alone.
Combined with the lactic acid fermentation we expect to reduce most of the pathogens
at the source. So using the lactic acid fermentation in the
toilet, and then using the worms later we will have definitely a beneficial effect based
on the results of the vermicomposting.
The necessary charcoal can be produced easily in woodgas stoves, where charcoal is a by-product
of highly efficient cooking. We have started working with groups, that deal with woodgas
technology. So that is a type of stove, that is not burning the wood, but it'ss gasifying
the wood, so that after the cooking there is charcoal. And this charcoal is ideal for
our type of Terra Preta compost. So we link with the people dealing with the renewable
energies. You just need the right temperature and anaerobic
conditions. And then you can turn, with or without water, everything, every bio-mass
into biochar. If you start charring wood or other bio-mass in a pyrolyses process, there
are generated a lot of pyrolyses gases. See, that you have a perfect ignition and all the
gases are burned. This can be done by stoves. The point is here, in this stove, that you
have actually anaerobic conditions. The great advantage is, that you make a gasification.
You get the pyrolyses gas out of it and you burn the gas in the upper part of the stove.
And, here you have a very clean burning. And then you have the nice residual, which could
be produced, because in the lower part of the stove it was anaerobic conditions. Actually,
everywhere in the world where you have some *** material, you can do it. You need small
amounts. Wood is a pure product, so you will also get more or less pure carbon. You need
to have some use for the heat. Because, always when you're doing a pyrolyses process, you
have some excess heat. And this should be used for cooking or industrial or other processes,
where you need the heat. So if you have a nice burning, a nice fuel from wood, then
you can use the heat and have still the char, that you can use on the fields afterwards.
Finally, the product of the composting process is Terra Preta soil, which is highly fertile,
and can be used as a soil conditioner. To make 100% sure, that there are no pathogens
left, the fresh Terra Preta soil should at first be used for non-food plants or necessary
reforestation purposes. After a few years, it will be absolutely save to use it for food-crops.
This method is another part of the multi-barrier system, guaranteeing a complete sanitisation.
Now, let's come to the final conclusions and perspectives.
This Terra Preta system is - as I said - based on ecosan system. It transforms excreta to
humus. But when you see the ecological sanitation approaches established so far, there are no
proper pathways for the treatment and further application of the excreta. There is an odour
problem in most of the systems. The pathogen reduction is not efficient. And the nutrient
conservation is also not efficient. So in this system the odour will be eliminated at
the source, when the faecal matter is collected. And a significant amount of pathogen reduction
will be achieved. And also the nutrients will be conserved. Then you have - finally you
have a save product which have ability to, or which - when you apply it on soil - it
will have a very beneficial effect. The main advantage of this type of sanitation
is that we don't have any contact to the water cycle. So we don't pollute ground water, we
don't pollute surface water. And this alone can save millions of lifes every year.
The ultimate goal will be to establish a system, a collection system for collecting human excreta
at households. And to develop a toilet, a suitable toilet as well, suitable for the
lactic acid fermentation process. We need to go to a scale of maybe 100,000
people, so that the production of the units, especially the toilet units, but also the
installation of small service companies, can be done. We are thinking to establish a service
provider, for example. Where there is a central system, where this provider will produce microbes
and provide them to the households. When this material is transported, the idea would be
that suction trucks will come. It could be a transportable tank, it could be a pipe,
that is connected to the toilet that is sucked out. That would even work in multi-story houses.
Sanitation is not a purely technical issue. It is an issue of social interaction, capacity
building, but also of economical systems, that can be operated at reasonable costs.
I'm really happy that we found a process, that can be included into cheap toilets,
that could be produced for 50 dollars. The operation of such systems, the collection,
and the composting would also be very cheap. (These are) systems, that can be serving the
poorest people. This is also something that has to do a lot with human dignity. We want
to develop systems, where each of us developers would accept the whole system in our own houses.
Each of us should - and does - operate toilets in that way. Up to now, we have found that
this is really very feasable so far.
So this, in a nut shell, is what we call Terra Preta Sanitation. This can become the standard
sanitation system of the future when it comes to resources recovery and to produce good
soil from sanitation. And, of course, we want to protect the water in a best way possible
because: water-bound sanitation will always pollute water. And so we want to get away
from that and develop toilets, that produce highly fertile soil.
So, this was our overview on the integral system of Terra Preta Sanitation.
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