Dear all

I do not really have time to follow all the discussion but I would like to emphasize that there is a difference between sustainable sanitation and ecological sanitation . Will try to put clarity to the terminology of ecosan and sustainable Sanitation and please note
there is no technical prescription of either dry or wet systems. The functionality of the system and the trade off of the resources gains are key for the understanding of ecological sanitation system.

In regards to Organic Food, urine has traditionally been used for production of organic food in Sweden - it was prohibited when we entered the European Union. Since then we have elaborated a certification system for urine and blackwater and there is a strong lobbying in Brussels that this kind of products will be accepted for organic agriculture again.
Note sanitized blackwater is not the same thing as sludge.

There are now very interesting waste composting schemes developed with larvae* which can be used as protein fodder and replace part of soya and fish protein which make this ecological loop very interesting.

And the most amazing thing with these system are reduction of medical residues and antibiotics with 90 % far more effecient that any sophisticated existing conventional treatment system.

There are many problem with conventional sewage systems; - they do not treat medical residues fully and antibiotics leaks out in our waterbodies
- most sewage system do not treat anything at all - 80 % of our sewage (worldwide) is not treated at all according to UNEP
- this totally uacceptable and unsustainable for numerous reasons.

It is necessary that we control and organize our waste in such a way that we use most of it in sustainable and safe manner. We have by the end of the day only planet to live on

Cheers
Madeleine


P.S.
Reminder:
Definition of Ecological Sanitation

Ecological sanitation systems safely recycle excreta resources (plant nutrients and organic matter) to crop production in such a way that the use of non-renewable resources is minimised.

The statement ‘safely recycle’ includes hygienic, microbial and chemical aspects. Thus, the recycled human excreta product, in solid or liquid form, shall be of high quality both concerning pathogens and all kind of hazardous chemical components. The statement ‘use of non-renewable resources is minimised’ means that the gain in resources by recycling shall be larger than the cost of resources by recycling.

The definition of ecological sanitation is focusing on the health, environment and resource aspect of sustainable sanitation. Thus ecological sanitation is not, per se, sustainable sanitation, but ecological sanitation systems can be implemented in a sustainable way and have a strong potential for sustainable sanitation, if technical, institutional, social and economical aspects are cared for appropriately.

* See here on the forum: forum.susana.org/forum/categories/147-pr...eta-or-organic-waste
(note added by moderator)

You didn't answer my point that the sewage sludge is generally not applied for its fertiliser value on the agricultural land, but rather as a convenient disposal mechanism (which is being questioned when the proportion of industrial effluent is high) - shown also by the fact that farmers usually get paid to take it.

I did actually address this point - sewage sludge certainly does have a fertiliser value but due to the limited number of ways to dispose of it, farmers are able to charge water companies. There have been a lot of studies on the fertiliser effects of sewage sludge some of which have quantified the economic value to farmers.

Nor did you answer my point that all the nutrients contained in urine would not be captured in such a system (you seem to have a strong foucs on faeces always (due to your public health concerns) but neglect the urine). When we are talking about nutrient recovery, urine is more important than faeces.

That is undoubtedly true. The urea in urine is overwhelmingly not recovered in this system. So if you are saying that the nutrients in both the urine and the faeces need to be recovered for it to be ecosan, I would probably agree with you. But then that isn't happening if you incinerate the faeces.

Also, I would be surprised if in 10 years time the ratio of 83% of sewage sludge being applied to land would still be as high in the UK. The UK is not exactly a leader in environmental protection issues (I hope this doesn't sound too harsh and arrogant now; I don't mean it like that). But if countries like Germany and Switzerland (whom I would see more as leaders in environmental protection issues) are banning the practice, there has to be a reason for it.

I would be very surprised if there is a substantial reduction - as there are public pressures against any other kind of disposal, particularly landfill, incineration and sea disposal.

In terms of pathogen reduction, incineration is probably the most effective, but is probably least ecological.

Dear Joe,

I hope that others will also join into this conversation as it would be interesting to hear their opinions, too.
And I worry that we are mixing up several topics in one thread, but so be it. (some people have told me they don't like how threads are sometimes split up)

So just some quick respones:

You didn't answer my point that the sewage sludge is generally not applied for its fertiliser value on the agricultural land, but rather as a convenient disposal mechanism (which is being questioned when the proportion of industrial effluent is high) - shown also by the fact that farmers usually get paid to take it.

Nor did you answer my point that all the nutrients contained in urine would not be captured in such a system (you seem to have a strong foucs on faeces always (due to your public health concerns) but neglect the urine). When we are talking about nutrient recovery, urine is more important than faeces.

For those two reasons above, I personally would not call such a system "ecosan" (unless in the theoretical case perhaps where there is no industrial effluent at all and where the liquid effluent (without nutrient removal) is also applied to land; I guess that might be the Braunschweig model that Arno called ecosan in the other thread).

Also, I would be surprised if in 10 years time the ratio of 83% of sewage sludge being applied to land would still be as high in the UK. The UK is not exactly a leader in environmental protection issues (I hope this doesn't sound too harsh and arrogant now; I don't mean it like that). But if countries like Germany and Switzerland (whom I would see more as leaders in environmental protection issues) are banning the practice, there has to be a reason for it.
Florian told us in his post here (forum.susana.org/forum/categories?func=v...089&limit=1000#10169):

I live in a country [Switzerland] where the agricultural use of sewage sludge is forbidden. All sewage sludge is burned in waste incineration plants or other facilities like cement factories.

Now, if that is the more "sustainable" way to deal with it, rather than the reuse of nutrients aimed for in other countries, I am not so sure.

It is not for public health reasons that it is banned. Dieseases are much more likely to spread via coughing in full busses and trains than via sewage sludge applied to fields! But it is banned in some countries for concerns of environmental pollution, i.e. contamination of soils (which could have unforseeen long-term effects on human and animal health). But this is all related to the industrial effluents so if your proportion of industrial effluents is really low in the UK, then it may be more acceptable than in Germany and Switzerland.

About the terms ecosan: I have never considered that ecosan to be anything other than the short form of "ecological sanitation".

My understanding of ecosan is that it could well include the technology "incineration" also (also UV, membrane bioreactors - everything). Anything that can be used to get safe recycling of nutrients to land, without causing environmental pollution. However with incineration, I think a lot of the nitrogen and organic matter would be "lost" to the atmosphere and there might also be air pollution, so this would have to be figured out.

I have tried to make clear in the Wikipedia article how the term "ecosan" has evolved from its first use:
en.wikipedia.org/wiki/Ecological_sanitat...he_term_.22ecosan.22

Plese tell me how I should modify it to make it clearer/better?

This is how it reads at the moment (the numbers in brackets refer to the citations, see Wikipedia article):

The term "ecosan"

The term "ecosan" was first used in about the 1990s (or perhaps even late 1980s) by an NGO in Ethiopia called Sudea. They used it for urine-diverting dry toilets coupled with reuse activities. It was further used and defined by Swedish experts, many of whom worked at Stockholm Environment Institute which had a program, called EcosanRes, running from 2001-2011 where they did research on ecosan. Important publications about the safety of reuse where published from that group which were also taken up in the WHO Guidelines from 2006. GIZ also had a large "ecosan program" from 2001 to 2012 which was led by Christine Werner during the period 2001 to 2008 who has authored or co-authored many publications on this topic.

In the early days during the 1990s when the term ecosan was something new, discussions were heated and confrontational. Supporters of ecosan claimed the corner on containment, treatment and reuse. The "establishment" defended deep pit latrines, and waterborne systems and they felt offended. Ecosan supporters criticised conventional sanitation for killing children, contaminating waterways with nutrients and pathogens and making helminth worms a global pandemic with upwards of 2 billion cases. Since then, the two opposing sides have slowly found ways of dealing with each other, and the formation of the Sustainable Sanitation Alliance has further helped to provide a space for all sanitation actors to meet and push into the same direction of sustainable sanitation.

Initially, there were dedicated "ecosan conferences": One in Bonn, Germany in 2000 followed by the "first" ecosan conference in Nanning, China in 2001, the "second" ecosan conference in Lübeck Germany in 2003 and the third one in Durban, South Africa in 2005. Since then the ecosan theme has been integrated into other WASH conferences, and separate large ecosan conferences have no longer been organised.

In the ecosan concept, human excreta and wastewater is regarded as a potential resource - which is why it has also been called "resource oriented sanitation". The term "productive sanitation" has also been used since about 2006.[17]

Regards,
Elisabeth

[Start of Page 2 of the discussion]


Just for completeness, this UK government report (page 19) reports destinations for disposal of sewage sludge. www.gov.uk/government/uploads/system/upl...waste-water-2012.pdf

In 2010 there were 1,412,836 tonnes produced, of which

1,118,159 tonnes used in agriculture (83% of the total)
23,385 tonnes used elsewhere (I think this is mostly forestry)
8,787 tonnes landfilled
259,642 tonnes incinerated
2,863 others

The report describes the move away from disposal of the faecal waste at sea due to the EU's Water Framework Directive

If there was some serious epidemiological impact of using sewage sludge in agriculture, we would certainly see it. We have a mixed system so industrial effluents are mixed with household wastewater - and whilst it is true to say that there are worries about the impact of heavy metals and other pollutants, these have been risk assessed as a minor possible risk to human health (but that is not to say that it is a sustainable system - it isn't).

On the use of the term 'Ecological Sanitation' - whilst it is true that 'Ecosan' is a shortened usage of the words, in practice it refers to a particular set of ideas which usually are seen in a small number of applications. Of course, at issue is how one defines the terms 'Ecological' and 'Sanitation' and which practices are included within the paradigm of 'ecosan'.

My point above on that was that it is possible to imagine centralised systems that recycle waste to land which are not sustainable (depending on how one defines sustainability, the idea of spending a lot of resources on equipment to run water treatment works cannot be sustainable) and to define 'ecosan' to refer to a certain set of accepted practices and 'Ecological Sanitation' to refer to sanitation systems which sanitise faecal pathogens via ecological means.

It would be interesting to survey the ways that the term ecosan is actually used to see if it includes these technologies listed by Elizabeth:

Time (as in urine storage tanks)
Drying for long enough time (as in faeces of UDDTs)
Composting (yes, this could be called "ecological means")
Increased pH (lime treatment)
Chlorination, UV disinfection, ozonation (wastewater effluent)
Incineration

Because if cholorination, UV, ozonation and incineration is ecosan then the British water treatment system is a form of ecosan. I think that makes a nonsense of the idea.

I think most people are describing something which is dispersed and is an alternative to pipes and treatment works when they use the term 'ecosan'. That isn't necessary the same as 'Ecological Sanitation' in my view.

It would be interesting to explore more about the origin of the term, but it would be very ironic if it was anything to do with 'Organic food' given that the use of human faeces is banned in all Organic food systems!

Would anyone describe incineration as ecosan?


[End of Page 1 of the discussion]

I think it is pretty important to get this straight, because it also comes through in the post you made here about dry systems (forum.susana.org/forum/categories/40-irr...2&start=12#10898) where you make it sound like dry systems, or let's say dry toilets, could never achieve full pathogen kill on a consistent level.

Absolutely correct. Without batch testing, dry toilets cannot be said to consistently achieve full kill (ie kill to levels considered safe in Europe). There is a lot of evidence that shows this.

I accept that dry toilets may be the best available technology in some places but they are certainly not consistent enough to replace N American and European centralised systems.

Here again you disregard the possibilities of combining different treatment steps, e.g. the drying at household level could be coupled with community-scale composting or if you want to be totally sure with incineration, lime treatment or whatever (not at the household level, but you also don't treat your organic kitchen waste or other solid waste at the household level either! You rely on the municipal collection systems).

Kitchen waste is in no sense as hazardous as faecal waste. But again I have not discounted any of this - dry toilets are not risky if you live somewhere without endemic faecal pathogens, where you have access to good healthcare and the risk reduces with each additional barrier. This does not change that countries with extremely low incidence of faecal pathogens would have worse health outcomes if the centralised systems were replaced with decentralised dry toilets.

Of course the risk calculation would be completely different if the centralised systems stopped functioning for whatever reason, in which case it may well be less risky to have dry toilets than non-functioning water treatment works. At the moment we do not have situation.

so I don't think such generalised statements should not be made, like what you said here:
"It is very clear that however inadequate the central systems are at destroying pathogens, they are several magnitudes more effective reliable than any dry system."

Dry toilets can destroy pathogen but it is impossible to tell how consistent they are without batch testing, and research suggests that they can be very inconsistent. This (batch testing) is completed regularly at every water treatment works.

Elizabeth, I just checked and more than two thirds of sewage sludge is used in agriculture in the UK. Some is incinerated and some is land filled.

Unfortunately the way you have quoted my post makes it say something I was not intending - I was trying to describe a difference between 'ecosan' and 'ecological sanitation' but I will have to post more clearly later as it is hard to quote posts on my mobile phone.

Dear Joe,

Your first statement ("Wastewater systems here in the UK mostly involve recycling of the solids to agriculture.") I have just addressed here (I don't think it is fully true, only partially):
forum.susana.org/forum/categories/17-fer...-human-excreta#10900

Your third statement I agree with:

I think it [eocsan] therefore can include pipes, sewers etc because it is not specifically describing the collection system but the means by which the faeces is treated.

But your second statement I don't agree with (emphasis added by me):

Ecological sanitation seems to me to be describing a process by which harmful microbes are destroyed by ecological means.

Now that we have a good Wikipedia page on ecosan (en.wikipedia.org/wiki/Ecological_sanitation), that we can hopefully all live with happily (if not: anyone is free to edit it ;-)), I ask you: where on that page do you find the statement that the microbes (pathogens) are destroyed by ecological means?

Far from it! They are destroyed by any means that works out best in a given context, or that give the necessary degree of construction (working with the multiple-barrier concept). This could be (in increasing order of complexity; and note that combinations are possible!):

• Time (as in urine storage tanks)
• Drying for long enough time (as in faeces of UDDTs)
• Composting (yes, this could be called "ecological means")
• Increased pH (lime treatment)
• Chlorination, UV disinfection, ozonation (wastewater effluent)
• Incineration

Have I forgotten any?

See also this image on the Wikipedia ecosan page:
en.wikipedia.org/wiki/File:Possible_tech...nable_sanitation.jpg

Possible technology components for sustainable sanitation by Sustainable sanitation , on Flickr

Where exactly the term "ecological" came in for ecosan ("ecological sanitation"), I am not totally sure, actually. Can any of the founding fathers & mothers of "ecosan" enlighten us?

I think it was more referring to the "closing the loop" aspect, that we are emulating nature in that way (a waste product, like e.g. the leaves from a tree, become a new resource - e.g. compost, new soil).
Or perhaps due to the "organic" fertilisers that can be produced from this, rather than the synthesised chemical fertilisers.

I think it is pretty important to get this straight, because it also comes through in the post you made here about dry systems (forum.susana.org/forum/categories/40-irr...it=12&start=12#10898) where you make it sound like dry systems, or let's say dry toilets, could never achieve full pathogen kill on a consistent level.

Here again you disregard the possibilities of combining different treatment steps, e.g. the drying at household level could be coupled with community-scale composting or if you want to be totally sure with incineration, lime treatment or whatever (not at the household level, but you also don't treat your organic kitchen waste or other solid waste at the household level either! You rely on the municipal collection systems).

So I don't think such generalised statements should not be made, like what you said here :
"It is very clear that however inadequate the central systems are at destroying pathogens, they are several magnitudes more effective reliable than any dry system."


Regards,
Elisabeth

Wastewater systems here in the UK mostly involve recycling of the solids to agriculture. It is in no sense ecosan, arguably is not sustainable (given it requires high levels of knowledge, maintenance etc to keep functioning) sanitation at all. I don't think therefore that the idea of 'reuse' can be an exclusive feature of ecosan nor of 'sustainable sanitation'.

Ecological sanitation seems to me to be describing a process by which harmful microbes are destroyed by ecological means . I think it therefore can include pipes, sewers etc because it is not specifically describing the collection system but the means by which the faeces is treated.

Dear Kai,

You provided a list of examples and asked us to say which one is "ecosan" and which one is "sustainable sanitation".
I think this is not really possible based on the brief descriptions you have provided (or maybe it would be a nice exam questions for students in an online course? ). The bottom line is still (for me): if a sanitation system has a strong focus on reuse (or resource recovery if you prefer that term), then it's going in an ecosan direction. When it has a strong focus to try and balance all five sustainability criteria (and this also includes costs, institutional and social aspects) then it goes into the direction of "sustainable sanitation". But it's not totally clear cut and probably becomes an "academic" debate at some point.

One thing is clear, nothing is ever 100% sustainable, we are using this term more to indicate a direction that we want to move towards.

Regards,
Elisabeth

madeleine - Your response is most curious given that I arrived at my interpretation from reading your words, "Thus ecological sanitation is not, per se, sustainable sanitation, but ecological sanitation systems can be implemented in a sustainable way and have a strong potential for sustainable sanitation, if technical, institutional, social and economical aspects are cared for appropriately."

So am I still confused?

Perhaps it would be easier to describe various systems to you and to then have you (and by extension SIANI) weigh in on which sanitation 'camp' you would place them in. Therefore, if you had to pick just one term - choosing between "ecological sanitation" or "sustainable sanitation" or "both" or "neither" - to describe the following systems which one would it be?

1. Decentralized system in a rural, peri-urban or urban area without access to typical Western system comprised of either decentralized and pressurized or centralized and pressurized water delivery, sewers and/or septic tanks but instead relying on rainwater harvesting and storage, onsite greywater systems, a mix of waterless UDDT's and conventional composting toilets, backyard processing and/or curbside (door-to-door) pickup of urine and desiccated feces, backyard and/or centralized processing center (for ageing urine and composting feces) and application of these materials onto farmland where crops are grown for the consumption of livestock and/or humans.

2. Braunchsweig.

3. Typical western municipal installation of centralized and pressurized water delivery, flush toilets, sewers, activated sludge wastewater treatment plants, collected sludge applied to farmland, effluent directed into nearby river or lake.

4. The same as #3 above except sludge is landfilled.

5. The same as #3 above except sludge processed in a bioreactor/anaerobic digestor to produce electricity, byproduct then applied to agricultural land.

6. The same as #3 above except all or some of the effluent is piped onto a tree farm and the sludge is incinerated (and the resulting fly ash is landfilled or used in the production of cement).

7. The same as #5 above except byproduct is landfilled.

8. System of centralized and pressurized water delivery, flush toilets, and sewers where sewers lead to a so-called "living machine" that uses various various flora and fauna to process wastewater into high quality treated water which is then released into a nearby body of water. The excess biomass generated is either composted and then applied to open land or utilized as a feedstock for an anaerobic digestor (the byproduct then being either applied to land or landfilled depending on its toxicity).

I hope its OK that I may have to follow up your response with a "why"; to ask you "why" you selected one term over the others. Maybe you can include your "why" if you think it might be controversial and/or unclear?

Thanks!

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