...In eastern part of Germany people have in average 70-90 l/d*person drinking water consumption, not knowing at all about ecosan definitions. Maybe they/we do not like to wash and smell different to the western German ...

Regards,
Detlef

Hello Kai,

"ecosan" is not some kind of certified label, with fix criteria that have to be fullfilled so you can stamp ecosan on your system.

Some think ecosan means UDDT, others think ecosan means "shitting in a bucket" or "some kind of composting toilet", you seem to think it should not involve sewers at all. That's all fine, but that is not as most people in the Susana community think about ecosan. The common understanding is well summarized in various posts here, for example the quoted Sandec definition above: Ecosan is a concept that strives for closing water and nutrient cycles and revovering energy as much as possible (but 100% is not always feasible of course).

The Braunschweig model is a good example that this can be done well also with sewers. I don't know the model personally, but from reading the documentation, the main difference to conventional German systems seems to be, that there is no nutrient removal treatment (which normally makes for about half of the energy consumption of a WTTP) but nutrients are used in the irrigation of crops. Nice. Shows what can be done on real scale in today's world.

If you read up a bit the contributions by Arno or Elisabeth on the historics of ecosan, you will see how the general understanding of ecosan has evolved in the last 10-20 years from being an exclusive niche concept meant as radical alternative to conventional system (close to your version of ecosan) to a more open and less confrontative understanding.

As for the nice grafic you linked above I don't know how many presentations I have done for giz using this grafic, and I can tell you that it is meant to be an idealised picture for illustrating the concept of ecosan, without wanting to exclude technologies or systems that are not shown in the grafic (such as blackwater sewers).

Ps: the water consumption figure of 193 L per capita probably does include industrial consumption as well. Purely domestic consumption in Germany is rather around 120 L/day on average (so for water consumption, Braunschweig is just normal)

cristoph,

Thanks for your response!

To your first point, the wikipedia definition that you referred me to (that appears in the first post of this thread) states that ecosan is, "...an ecologically and economically sustainable wastewater management system...." Can we agree that Braunchsweig is the antithesis of this? Sewers are an ecological disaster and legacy wastewater systems as a whole are economically unfeasible, particularly as we transition away from a fossil fuel economy and as climate change really sets in.

To your second point, I don't see the Braunchsweig model so much a "good start" as an example of a system whose time has passed; its exactly the type of system that we should be moving away from not towards. My understanding is that ecosan is the remedy to the epidemic that is legacy wastewater systems, not the other way around.

And to your third point while I agree that 113 liters per person per day of direct onsite water usage is great (and what each of us in the industrialized world should be aspiring to) I'd love to know where this figure appears in relation to Braunchsweig. Reference to this figure is absent from the English language portion of the website plus I'd love to learn more about how the city has created such a deep conservation ethic when it comes to water usage. After all that's ~40% less then the rest of Germany (and Germans) who apparently use ~193 liters/person/day:

Source - www.data360.org/dsg.aspx?Data_Set_Group_Id=757

First, for the record, I don't at all think there's "too much ecosan" on this forum.

Second, arno - thanks for responding to my question and also for supplying the diagram.

However, this is the pictorial diagram describing ecological sanitation that I'm most familiar with:



Source: "Ecological sanitation cycle-en" by Barbetorte - Own work by uploader ; original diagram by GTZ. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - commons.wikimedia.org/wiki/File:Ecologic...itation_cycle-en.svg

...and you will note that nowhere in the image is there depicted a sewer (or any of the "baggage" that accompanies it). Also, since its physically impossible to patrol sewers to ensure that only the safest materials are disposed of in them (i.e. toxic-free washwater and sodium-free soaps) there's no way that the sludge being produced in the Braunchsweig system isn't identical in composition to the sludge that's produced elsewhere in every other sewered system; in other words laced with industrial toxics, excess pharmaceuticals, radionuclides, antibiotic resistant bacteria, etc. You wrote, "...since all the upstream sources of toxins need to be regulated," but that just isn't at all the case (and will never be the case in a system based on centralized sewers as long as the chemical industrial complex exists). Our sewers are nothing if not soups of synthetic toxins.

So, I don't think its a matter of semantics so much as its Braunchsweig's system just not being ecological (and therefore not ecosan). Am I off-base in saying that among other things the last thing that purveyors of ecosan wish to see is the creation of toxic sludge followed by this highly toxic material then being dumped on agricultural land (or in our gardens, etc.)? As I wrote before and from what I can still tell, aside from the land application of wastewater, there's basically no difference between the Braunchsweig model and the legacy wastewater infrastructure that those in the industrialized world are familiar with.

Here's the test. We have to ask, "Where's the ecosan?" In other words, where are the dry toilets? Where's the source separation? Where's the curbside collection service (for the byproducts of ecological toilets)? Where's the onsite greywater? Where's the onsite rainwater harvesting and storage? Where's the SuDS/green infrastructure? Where's the centralized facility for composting ("co" or otherwise) desiccated feces? Where are the centralized holding tanks for urine? And on a broader level, where's the low-energy footprint and where are the safe and low-cost sanitation solutions that will stand the test of time? When I look at the Braunchsweig model all I see is a conventional (read "legacy") system comprised of centralized and pressurized house-to-house water delivery, flush toilets, drains that empty everything (washwater, greywater, yellow water, blackwater and everything else that gets poured down drains and flushed down toilets) into an extensive sewer, all leading to a wastewater treatment plant which churns out toxic sludge and effluent, both heavily laced with the toxic detritus of "modern" society. It doesn't get much more routine and "conventional" than that. I ask "so what" that the treated effluent is used to irrigate croplands (instead of being discharged into surface waters)? And "so what" that some of the resulting crops end up as feedstock for a biodigester? That's all well after the fact and has nothing to do with ecosan. I just don't see any connection here to what I've come to understand as ecosan.

Certainly we can agree that there's nothing "ecological" or "economically sustainable" (to borrow from the wikipedia definition posted earlier) about a) centralized and pressurized water delivery systems (and all of their attendant waste and excess AND reliance on extensive infrastructure), b) sewers (and their massive installation and maintenance costs AND unsustainable reliance on water AND conveyance method for all things toxic) and c) wastewater treatment plants (and their massive energy and capital intensive footprints AND creators )? If so, then we have to also agree that Braunchsweig is not ecosan.

Am I alone in my concern that if we start including very modestly tweaked legacy systems in our definition of "ecosan" that we risk co-opting the very concept of what is undeniably the future of sanitation, in other words low-water, low-energy and low-cost ecosan? What's next, sludge industry professionals starting to refer to themselves as "ecological sanitation technicians"? That's a terrifying thought, but one that's already occurring and that has its origins in the deceptive coining of the term "biosolid" by the United States EPA. To be blunt, call Braunchsweig whatever you wish but please don't call it "ecosan".

As Neil MacLeod, lauded ecosan implementer and former director of Water and Sanitation for the award winning eThekwini Municipality in Durban, South Africa, has stated, "And we're saying that we cannot carrying on using flushing toilets; nobody can, not even the rich people." Braunchsweig is absolutely not exempt from this fact.

Source (commencing at 0:35):

Kai/Christoph
Have a look at the diagram here that describes the Braunchsweig system including the energy production.



It's a question of semantics if you can't call this ecosan. Applying digested sludge on arable land to produce food for local consumption is a major feat since all the upstream sources of toxins need to be regulated. This is very much like the REVAQ certification system we have in Sweden for STPs. The sludge produced in the certified STPs can be used in food production thus guaranteeing eg that the heavy metals like cadmium are not a source of risk.

Dear Kai,
a) have a look at the definition of ecosan - Elisabeth posted the definition in the first post of this thread. Sewer or not does not define ecosan.

b) I think the "Braunschweig Model" could be discussed very much I agree, but basically.... the use of water and sludge on land for creating crops in a controlled manor, controlling nutrient use and heavy metals and other substances is a very good start in my eyes. But I agree there is a lot of potential to enhance energy use, etc.

c) “excessive use of drinking-quality water” - Braunschweig used 113 l/pe in 2012 . I consider this a very good number (I understand the point that you are talking about drinking water for toilet flush … but in the worldwide reality this is not a bad number).

So I guess one could call it an Ecosan model, even though I as well don´t feel that comfortable about it, as it was born out of the history of land application and not with a view to reuse.

Christoph

Note by moderator (EvM): Kai's post is referring to this post by Arno:
forum.susana.org/forum/categories/39-any...here-a-problem#10029

Kai's post and the ones the followed until 11 September have been moved into a new thread to make it easier to follow the discussion.

Posts about sewage sludge (toxic sludge) have now been moved out of this thread into a separate thread here .

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


Thanks to all - I'm thoroughly enjoying this discussion.

Arno - this seemed to slip by, but with all due respect, how exactly is the "Braunschweig Model" ecosan? To me this seems the antithesis of ecosan. Isn't it just a glorified centralized system of sewers (and thus sewage), wastewater treatment plants and land application of wastewater and sludge? Just because the treated wastewater and sludge is dumped onto agricultural land rather than into surface waters (or, for that matter, into landfills or into our gardens by way of Class A sludge processing) doesn't make it ecosan. Generally speaking, most of the same risks that exist in our legacy sewered systems exist here (industrial toxics and excessive use of drinking-quality water being the most obvious standouts). As far as I'm concerned, any drain that leads to a wastewater treatment plant is by definition not part of an ecosan approach. Or am I missing something?

I look forward to your reply.