Hi Elisabeth, really sorry about the delay in posting a reply. Liked your history of ecosan wikipage.

Maybe you could consider including Mayan civilization also.

I think it is very important to study Mayan civilization. Remove all the fancy names we give our "modern" technologies but much of what we are doing now are tech they used to have all those centuries ago - and these civilizations vanished / not in their state of former glory. There are probably important risk factors to be found from the study of ancient civilizations, particularly, Mayan and ancient Egyptian civilization. There is an academic discipline called " technology and society ". I wonder if your wikipage and this post relates to this discipline and if people who know "technology and society" discipline can also contribute to this discussion topic.

Why did the Mayans have such high technological progress but not so much of literature and mythology (or, maybe, I don't know about it) like Indus Valley or Chinese? There is a theory (not sure which discipline - just remember reading it somewhere) that humans are first nomads, then they settle down along river sides and once they get leisure time (agri + no constant travelling), they start developing new tech, arts and culture, etc. I had previously thought that literature is one of the first one to grow but Mayans had focused on tech so much and not literature. Why? Why did the Egyptians, after inventing papyrus, not write poetry and fiction (even if it was only restricted to exclusively mythology and/or philosophy)?

And, I sincerely hope the above will not be thought of in a negative sense. I find the study of ancient civilizations really interesting, just like the Mahabharata and Ramayana - messages handed down over centuries, only we need to decipher them correctly. See which civilizations developed along which lines, what could be possible reasons? The world did not have "enabling technologies" for globalization, for an inter-connected world. So, the "natural" factors (climate, rainfall, geology, etc.,) could have played a more significant role than it does in our present-day times. I have just begun my study. Maybe it is all 'blue stocking' stuff, history and all that, but I find it fascinating.

Can you also look up the book, ' Guns, germs and steel ' by Jared Diamond and see if he has written something about feces. Interestingly, one of the contenders for the Mayan collapse theory is infectious diseases - particularly diarrhoea. Now consider what happened. They were using human feces as fertilizer, had developed very intensive agri methods and it was still inadequate. We have seen it around the world with current ecosan practices that people do not always wait for the feces to dry completely before using it in agriculture - I think this was found in Vietnam also, if I remember correctly. All that was required was for the ancient Mayans to use the feces which had not been made safe ('exigencies of the moment') and, with already existing rampant soil erosion, one flood could have resulted in large scale incidence of diarrhoea.

Study of ancient civilizations probably is a weird way of identifying risks, how to find scenarios to do risk assessment for, etc., ... anyway, just thought you might want to look up the use of human feces in Mayan civilization. Are there any articles on the use of human feces as a "traditional" agricultural practice in present times (as opposed to doing it as a result of spreading the modern ecosan concept)? I would like to know more about it and also, if there are any studies on the long-term soil effects / differences between (a) agricultural fields (where feces has been used as traditional practice), (b) fields where feces is used as a result of modern ecosan practice and (c) others where synthetic fertilizers have been used. Particularly interested in rhizobia though other soil quality parameters are of interest too.

One more question. Where can we find a collection of systematic reviews and/or meta-analysis relating to (a) sanitation and (b) agriculture? (Something similar to Cochrane Collaboration for medical information.)

Not sure if I would be able to reply often enough at present but thought it would be great to have a discussion on the above.

Warm regards,

Sowmya

Kai, I think the idea behind Class A sludge in the US is to reduce red tape for operators of water treatment facilities - in principle, that's not a bad idea, depending on how it's performed. Composting or lime treatment can, indeed, be effective in killing pathogens, and if the source of the waste water is ok, there would, in my opinion, be little to worry about. It all depends on the situation.

H-A - Sorry if what I wrote was confusing. To clarify, Class A and B sludge are both subject to the same front-end testing which controls for a handful of heavy metals, some indicator bacteria and, at least in Vermont, PCB's. The exothermic reaction requirement can be met via composting, the addition of lime or other methods. I used the term "limited' because relative to batch composting, many times the process used is very short in time-frame, maybe only a few minutes in duration (at a specified temperature). The way the federal regulations are written Class A basically gets a pass once the initial testing is performed. That's the concerning part; many of the heavy metals and industrial toxins present in Class B remain in Class A but the later can be spread anywhere and in any quantity - there's no follow-up testing of any sort required. Its as if we've expanded the borders of our landfills and/or regulated Class B disposal areas to include basically everywhere.

Interesting reading, Kai! I thoroughly enjoyed the story!

Concerning Class A sludge in the US, do you mean to say that no tests on pollutants are required, i.e. heavy metals, etc.? And what is meant with exothermic reaction? Is it composting? For pathogens, I can follow the logic, but heavy metals?

H-A

Two points:

1) Joe - a big push is underway in the United States (and Canada) to upgrade wastewater treatment facilities such that they can produce what's known here as "Class A" sludge. The only difference between Class B sludge (dewatered solids direct from a WWTP) and Class A sludge is a limited exothermic reaction and associated stricter limits on pathogens and 'vector attraction'. Amazingly, following heat treatment Class A sludge (and products containing it) can be applied anywhere and in any quantity; all of the followup monitoring and threshold requirements associated with Class B go away completely.

2) Elisabeth - Have you run across this history of dry toilets and reuse in historic Japan before?

faculty.unlv.edu/wjsmith/smithtest/Urban...Industrial-Japan.pdf

Very excited about the work underway to flesh out the historical aspect of ecosan! Thanks to everyone involved.

From memory, there is about 1.5 million tonnes of sludge produced of which nearly million tonnes goes to land in the UK.

I will check more accurate numbers tomorrow but very little goes to landfill.

I agree nutrients are lost from the effluent, but sewage sludge is most definitely used as a fertiliser and has a measurable nutrient load, payment is usually required because the farmers know the water companies only have a limited number of places they can dispose of it.

Dear Florian,

thanks for providing that example from Vietnam, I will see how I can add that to the article in the next few days. Very interesting stuff.

Who knows when we run out of phosphorus one day (phosphorus being a finite resource) we might "go back to the roots" to satisfy our fertiliser needs (I should probably also mention this in the Wikipedia article!).


Dear Joe,

Yes, good point. I was meaning nutrient recovery from "dry systems", i.e. non-sewer based systems. One could argue that this explanation of the histroy of dry systems could becaome a Wikipedia article on its own because right now it's on the ecosan page, even though ecosan can be "dry" or "wet". If I build up that section more, then it could be a good move to make it into a distinct page in the future to avoid confusion if ecosan has to be always "dry" or not.

To address the misunderstanding, I have now modified the section on history as follows - I have highlighted my changes in red (or just read here: en.wikipedia.org/w/index.php?title=Ecolo...l_sanitation#History):

Excreta reuse in dry sanitation systems
The recovery and use of urine and feces in "dry sanitation systems", i.e. without sewers or without mixing substantial amounts of water with the excreta, has been practiced by almost all cultures.

and

Even as the world became increasingly more urbanised, the nutrients in excreta collected from urban sanitation systems without mixing with water were still used in many societies as a resource to maintain soil fertility, despite rising population densities.

and

Decline in recovery of nutrients from human excreta in dry systems
Recovery of nutrients and organic matter from excreta and greywater in non-sewered sanitation systems was addressing the sanitation problems in settlements in Europe and elsewhere and was contributing to securing agricultural productivity

You say that in the UK agriculture is the largest endpoint for human faeces. Well I am not sure this is really true. I guess you are referring to the sewage sludge?
Firstly, I doubt that all sewage sludge in the UK is applied to land? Isn't a good proportion also dumped at sea, landfilled or incinerated? In Germany, only some of the states still allow land application, e.g. Bavaria, but the general route for most of the sewage sludge is incineration (as far as I know; if someone has the figures at their finger tips, please provide them).

Also the nutrients from the excreta (at least from urine but also partially from faeces) are only partially recycled because a good proportion of the nutrients will be in the effluent from the treatment plant (not in the sewage sludge), and this effluent either gets tertiary treatment to remove the nutrients or it doesn't and is simply discharged to surface waters (sometimes leading to eutrophhication there).

The "reuse of nutrients" that can take place via sewage sludge is normally not really intentional - it is more of a convenient way to get rid of the sewage sludge which is also why farmers usually get paid to take the sludge, rather than them paying to get their hands onto this fertiliser.

Nevertheless, you are right that a nutrient recycling via centralised wastewater treatment plants is possible (see also that Braunschweig example: forum.susana.org/forum/categories/40-irr...s-it-goodsustainable)

Therefore, I have added this to the Wikipedia article to explain this to lay people:

Even in situations where dry sanitation systems have been replaced by sewer-based sanitation systems, the recovery of nutrients from wastewater may continue in two forms:

• Wastewater reuse or resource recovery: Use of raw, treated or partially treated wastewater for irrigation in agriculture (with the associated health risks if it is done in an improper way which is often the case in developing countries); and
• Application of sewage sludge to agricultural lands which is not without controversy in many industrialised countries due to the risks of polluting soils with heavy metals and micropollutants if not managed properly.

Would you say it is clearer now?

Regards,
Elisabeth

I might be misunderstanding your question Elizabeth, if so apologies in advance - however it is not accurate to say that the use of faecal wastes in agriculture has been abandoned in the UK. In fact I think the use in agriculture is the largest endpoint for human faeces here and that it has been used in this way for a considerable time.

Of course the system here is not ecosan so maybe that is the point you are making.

muench wrote: If anyone has further examples and details to add to this section on historical developments of human excreta reuse in agriculture (also from other parts of the world), please bring them to my attention or add them into the Wikipedia article yourself.

Dear Elisabeth,

I think Vietnam is also interesting, eventhough of course not too different from China.

In rural areas, people would collect every bit of organic waste to fertilise paddy fields, and of course this included human feces. In the 50s, in northern Vietnam, the double vault toilet was strongly promoted to make this reuse more hygienic, and it was widely used in rural areas. Some details here .

In the towns and cities, people used mostly public toilets in the neighborhoods, which were bucket toilets or simple vaults. The toilets were emptied by farmers in the night and the stuff brought to the surrounding rural areas. My wife, a Hanoian, told me that in her childhood in the 80s, they would cycle behind those farmers transporting barrels full of shit on their bicycles, and make fun of them because they were so smelly.

Actually there were villages around Hanoi specialised in the collection business (villages in Vietnam often specialise in one type of commerce or craft), and selling the fertiliser to farmers around Hanoi.

With growing living standards, people in the cities started to construct toilets in their houses, which were flush or pour flush toilets connected to a septic tank or similar. They abandonded the public toilets and the people in the shit collection villages had to switch to other business.

In the rural areas, the double vault toilets still can be found, but with some delay, the same development happens, and people construct indoor flush toilets. All people I talked to in northern Vietnam know about the double vault toilets, they usually consider it as a rural thing from the old poor times.

When I talked to farmers (in 2001), they said that they know the value of human waste, but there is not more available from the towns and their own is just too little for what they need on the field, so the reuse of human waste is not relevant any more to them..

Vietnam also had interesting integrated aquaculture-agriculture systems for households, where ponds, vegetable fields, lifestock and toilets are all part of a well thought resource cycle systems. Some short info here: www.fao.org/docrep/005/y1187e/y1187e10.htm#TopOfPage. These are still around, but are not promoted any more.

These integrated agriculture system and also the double vault toilet were developed and promoted in the times of serious poverty and shortage of resources, when mineral fertilisers were not available and nutrients in human and agriculural waste were of high value. Today that's not the case any more.

As for the history bit in the wikipedia article, I think it already summarizes well the issues that led to the dissapearace of the nutrient recycling in this example.

Regards, Florian

Dear all,

This post is for people who have an interest in the history of ecosan or more precisely an interest in the history of human excreta reuse in agriculture - and what caused it to stop in European cities at least.

You can read up about it here now on Wikipedia where I improved some existing information about the historical developments of human excreta reuse in agriculture:
en.wikipedia.org/wiki/Ecological_sanitation#History

I am for sure not an expert in that field, but we have an expert in our ranks and that's Patrick Bracken (and others?). So I took inspiration from some sentences from his landmark paper in 2007 ("The road not taken: how traditional excreta and greywater management may point the way to a sustainable future" - web.stanford.edu/group/narratives/classe...WS&T07GryWtrMgmt.pdf) which I have now cited in the Wikipedia article (and which also made its way into the sustainable sanitation in cities book from 2011 (www.susana.org/en/resources/library/details/1019)).

I also got information from Catalina Maya Rendón who sent me an example from Aztec Culture in Mexico which I have now included (a paper from 2007). (Catalina is the one doing this really interesting work on helminth egg quanitification and she is helping me greatly with additional information for the Wikipedia page on helminth infections - but that's for another post).
I just wasn't quite sure what time frame this was, i.e. when exactly it ended - I guess it ended when the city was destroyed by Spanish conquerors?
This is how I summed it up:

In Mexico the Aztec culture collected human excreta for agricultural use. One example for this practice has been documented for the Aztec city of Tenochtitlan which was one of the last cities of pre-Hispanic Mexico: In the 15th century, the inhabitants collected human waste and transported it in canoes to be used as fertilizer in agricultural fields or sold in the market to as tanning animal hides. Urine was also collected to be used later as a mordant for dyeing cloth. The Aztecs recognized the importance of recycling nutrients and compounds contained in wastewater.

Source:



If anyone has further examples and details to add to this section on historical developments of human excreta reuse in agriculture (also from other parts of the world), please bring them to my attention or add them into the Wikipedia article yourself. Thanks.

By the way, one aspect that came up for causes that put an end to this practice in England is the miasma theory and there is a fairly decent Wikipedia page on that too, so I added a cross-reference from that page back to the ecosan page (en.wikipedia.org/wiki/Miasma_theory#The_..._reforms_in_the_West)

Regards,
Elisabeth

P.S.
Perhaps if we had had good Wikipedia pages about ecosan at the outset of this debate, we would have had a shorter debates on what ecosan is and what it is not (how boring!)
(links to our previous long debates about ecosan: forum.susana.org/forum/categories/39-any...n-is-there-a-problem
and forum.susana.org/forum/categories/40-irr...s-it-goodsustainable)

Check out the much improved English page on ecosan:
en.wikipedia.org/wiki/Ecological_sanitation

I have also improved the page on sustainable sanitation, although more work is needed:
en.wikipedia.org/wiki/Sustainable_sanitation