Dear all,

I am happy to announce that the test version of ECAM V.2.2 including faecal sludge management is now available.

We are currently peer-reviewing, testing and translating it before the tool will be officially launched. If you have any feedback or questions, they are very welcomed.

If anybody here is interested to participate in a more in-depth peer-review please send me an e-mail.

@Elisabeth: Thank you for sharing the links and adding the link to thread about ECAM

Regards,
Ranjin

Dear Ranjin,

You asked about "default values regarding the composition (e.g. total N, TVS) of different kinds of faecal sludge". In case you haven't seen these threads yet, I think you'll find some useful information here on the forum:
forum.susana.org/wastewater-characterisation
(it's our forum sub-category on "Wastewater characterisation and mathematical modelling")

In particular the new tool by Dorothee:
Tools for the generation of sanitation systems considering novel technology options and for the quantification of nutrient, water, and total solid balances at the scale of an urban setting
forum.susana.org/wastewater-characterisa...-urban-setting#26047

Please keep us informed about your progress.

Regards,
Elisabeth

Dear community,

this topic was created quite some years ago but I've read it with great interest. I am actually working right now on a tool to estimate GHG emissions from containment, (emptying and) transport, treatment, resuse and disposal of faecal sludge. It shall be included into the ECAM tool very soon.*

What the tool will do is estimate the emissions based on IPCC and other literature references. The calculations will rely on a lot of default values for the characteristics of faecal slduge while the user will be also able to insert some more precise data if available.

I am currently still looking for some default values regarding the composition (e.g. total N, TVS) of different kinds of faecal slduge including raw faecal sludge, dried, dehydrated (from UDDT), digested, composted, pit hummus etc. If you have an idea where to look or have any thoughts to share on this I'd be happy to hear from you.

Many thanks in advance!
Ranjin

* Note by moderator: see also this forum thread about ECAM: forum.susana.org/195-climate-change-and-...urban-water-services

Hi,

I recently came across a research paper from 2014 on the topic of this thread which I found quite interesting (it was pointed out to my by Mona on twitter) - the pdf file is available for download here:
www.princeton.edu/~mauzeral/papers/Reid....trines_ES&T_2014.pdf

Global Methane Emissions from Pit Latrines
Matthew C. Reid,*,†,⊥ Kaiyu Guan,§ Fabian Wagner,∥ and Denise L. Mauzerall†,‡
dx.doi.org/10.1021/es501549h | Environ. Sci. Technol. 2014, 48, 8727−8734
pubs.acs.org/doi/abs/10.1021/es501549h

It says that 2 % of anthropogenic methane emissions come from pit latrines. Is that a lot or not a lot? Well, if there is any way we could avoid these methane emissions, that would be good in any case.

The paper focusses mostly on estimating the amount of methane from pit latrines but also discusses what role composting toilets could play with their lower methane emissions.

The paper says:

Composting toilets and household biogas
digesters were considered as abatement technologies, and
this approach assumes zero CH4 emissions from either
treatment system.

(might not be strictly true as composting toilets also have some anaerobic zones - see our discussion here: forum.susana.org/forum/categories/70-com...omposting-in-general , 3 pages)

The paper also says (once again ecosan toilets are equated with composting toilets...):

More fully aerobic disposal can be achieved through the use of
well-maintained composting toilets, also known as ecological
sanitation (“ecosan”) methods. Composting toilets separate
liquid and solid waste, and with proper maintenance the solids
decompose aerobically to a nutrient-rich compost within a few
months.18 Composting toilets have traditionally been promoted
for their low water use, avoided groundwater contamination
relative to pit latrines, and the opportunity for nutrient
recycling.26

Composting toilet fans will enjoy this:

Composting toilets have traditionally been promoted for
reasons unrelated to CH4 mitigation, so the recognition of a
new benefit in CH4 emissions reductions will only add to their
existing advantages and may attract financing based on GHG
mitigation opportunities.

and this:

This analysis demonstrates that the problem of pit
latrine CH4 emissions can be reframed as an opportunity to
incentivize progress up the sanitation ladder to composting
toilets or more advanced systems, yielding cobenefits for both
GHG mitigation and water and sanitation development.

I would tend to agree with these statements from the paper (even though I know that consumer choices regarding their "preferred" toilet type will be unlikely to be swayed by greenhouse gas emissions arguments; it could however have an impact on funding schemes?).

The Abstract from the paper:

Pit latrines are an important form of decentralized
wastewater management, providing hygienic and low-cost
sanitation for approximately one-quarter of the global
population. Latrines are also major sources of the greenhouse
gas methane (CH4) from the anaerobic decomposition of
organic matter in pits. In this study, we develop a spatially
explicit approach to account for local hydrological control over
the anaerobic condition of latrines and use this analysis to
derive a set of country-specific emissions factors and to
estimate global pit latrine CH4 emissions. Between 2000 and
2015 we project global emissions to fall from 5.2 to 3.8 Tg y−1,
or from ∼2% to ∼1% of global anthropogenic CH4 emissions,
due largely to urbanization in China. Two and a half billion
people still lack improved sanitation services, however, and progress toward universal access to improved sanitation will likely
drive future growth in pit latrine emissions. We discuss modeling results in the context of sustainable water, sanitation, and
hygiene development and consider appropriate technologies to ensure hygienic sanitation while limiting CH4 emissions. We
show that low-CH4 on-site alternatives like composting toilets may be price competitive with other CH4 mitigation measures in
organic waste sectors, with marginal abatement costs ranging from 57 to 944 $/ton carbon dioxide equivalents (CO2e) in Africa
and 46 to 97 $/ton CO2e in Asia.

Regards,
Elisabeth

P.S. Seeing climate change also as an opportunity for innovation in sanitation reminds me of this wonderful cartoon, seen on twitter (thanks to Pete Cranston's retweet):

pbs.twimg.com/media/CV2-ienWUAAyH9G.jpg:large

Hi Michel,

Thanks for your interest in this topic! I supervised Lars and the rest of the group. they did a really great job and I was excited to publish their results. But unfortunately they made a couple of minor mistakes which really influenced the overall calculations. I've been trying to get the group to make the corrections but they've all moved on now. So I don't have a final report I could share but I could try and answer any specific questions you have? They didn't work on vacuum toilets, and I'm not sure that they considered the fabrication of conventional toilets - they focused on the treatment processes.

Certainly getting data was a big challenge and the group did a really good job of triangulating information from various sources.

Alison

Dear Lars and former participants of this post,

For a university project (Universidad Politecnica de Catalunya, Barcelona) I am currently also working on a LCA study on a similar topic. We are analyzing the environmental impacts of three different types of toilets, that are more or less established in the European context. The conventional toilet, the vacuum toilet and a integrated model, that reuses the greywater of the basin.

Now that I found this threat, first I am super interested in the outcomes of your project, Lars, which is now nearly a year ago.

Further more, as we are facing some problems in getting specific data on the web and the companies, we contacted are not willing to cooperate (or really slow in responding) if you could share with us the input data you collected already.

To everyone: I would be happy to get any hint of sources regarding the fabrication process of water and vacuum toilets

Greetings and thank you in advance,
Michel

Dear Lars,

How has your research progressed by now? I saw on Twitter that Alison mentioned a paper that is coming out soon, does that mean your research has already been concluded?

She said on twitter:
e.g. the @WSUPUK project illustrated the low carbon footprint of ecosan vs a sewered system or even a simple pit latrine #sanitation

@Ostella42 @WSUPUK We're working on a journal paper with the results so it should be in the public domain soon!

Otherwise, I just wanted to make sure you had seen this MSc thesis? (is it any good?) :

susana.org/lang-en/library/library?view=...eitem&type=2&id=1596

Diafarou Ali, M. (2009). Carbon dioxide and methane emissions from different wastewater treatment scenarios. UNESCO-IHE Institute for Water Education, Delft, the Netherlands. MSc Thesis (MWI/SE 2009/39).

And I also followed the lead that Christoph Platzer gave us in his post above and searched the archive of the old Ecosanres Discussion Group for the topic of Greenhouse Gas Emissions (groups.yahoo.com/neo/groups/ecosanres/info) (this group was closed when the forum started, but was active in the years 2002 to 2012)

I found various things there in the archive but the only thing really of relevance here, I think, is a post by Chris Canaday (our featured user of this month!) from 2009 where he wrote:

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

Dear David,

The message you mention may have been one of mine (which Ian kindly found and resent), in which I mention the conceptual reasons that EcoSan reduces Greenhouse Gas (GHG) Emissions and encourage someone to work out precise numbers.

I would like to take this opportunity to complete a bit the list of reasons that UDDT toilets contribute to controlling the Greenhouse Effect:
(a) reduced methane emission by avoiding anaerobic fermentation of feces in water,
(b) increased CO2 sequestration via fertilization of plants and trees,
(c) increased carbon sequestration into the soil via integration of organic matter,
(d) reduced use and transport of chemical fertilizers (another source of GHGs),
(e) reduced use of petroleum for pumping and treating water.
(f) reduced demand for cement for building large sewers (since cement production is a big source of CO2).

I am convinced that the UDDT of one of the simplest and least painful ways we can reduce our "Carbon Footprint" and our "Ecological Footprint" in general ... and that this will be very evident to all interested parties once the numbers are worked out, especially taking into account all of these 6 factors. Most other options involve walking more, colder houses, not consuming whatever we like, etc., which impinge more on people's lifestyles ... but the psychological barrier of the UDDT has to be jumped.

There is a mention of this on page 126 of Ecological Sanitation (2004. Winblad et al.) It would be great if the corresponding bibliographic citations (and more recent articles) were available on-line.

UDDT advantages in adapting to Global Climate Disruption are very clear: (a) less demand for precious water and (b)improved water-holding capacity of soils.

For these reasons, we should be able to access various Global Climate funds for building UDDTs. One way would be to set up, or work with existing, villages in desertified areas and build UDDTs (thus reducing methane emissions of people who had previously been using flush toilets) and use the greywater and EcoSan fertilizers to cultivate fruit trees in the desert around the village (thus sequestering carbon into tree trunks and soils) ... and creating livelihoods and economies where previously none existed. Maybe we can collectively spark something.

One student member of this forum, Diafarou MOUMOUNI, responded that he is doing his master's thesis on a comparison GHG emissions from various wastewater treatment options, including the (non-wastewater-producing) UDDT. We can all look forward to seeing his results as they come out.

Best wishes from South America,
Chris Canaday

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

Hope this helps and I hope you will give us an update on your research?

Regards,
Elisabeth

Dear Lars,

I am currently working with an organization in Nairobi/Kibera called KDI. One of there projects was a composting toilet system. They did a very good job on the design.

Are you working in Sub-saharan Africa, too? What is your location and any design considerations so far?

Greets,

Andreas

Hello Canady,

you might get some -measured, quantified- results from a French NGO called "Solidarités"; this NGO was a project partner of me resp. my employer and built an operated covered latrines in a Rohingya refugee camp in south-eastern Bangladesh. They collected the gas and used it for fuel in the camp's kitchen with some success in 2011/2012. They might be able to give you some of their quantifications about volumes and quality of the gas.

Regards,

Jürgen

Dear long term users,
I was trying to remember. I have the impression we already had a specific exchange about greenhouse gas emissions of latrines and UDDT trying to calculate both, one comparing to the other. This was about 3-4 years ago, maybe still in Ecosanres. I tried to remember but I could not find it quickly so I just do this reminder to the others.

Yours
Christoph

Aloha Lars,

If you can, please try to do at least some quick-and-dirty gas measurement, since the real world conditions can be complicated and unpredictable ... and a priori assumptions could lead the wrong way.

If in fact no one has done so, someone urgently needs to cap a pit latrine and measure the gases emitted within.

Here is some support for my assertion that soil microbes can consume Greenhouse Gases:
((Bacteria can consume GHGs))
en.wikipedia.org/wiki/Methanotroph
www.goucher.edu/Documents/verge/papers8/...balClimateChange.pdf
books.google.com.ec/books?id=ZKPxFINHDH4...20methane%22&f=false
((Fungi play a role))
eco.confex.com/eco/2010/techprogram/P23645.HTM

Best wishes,
Chris Canaday

Aloha Chris,

Many thanks for your reply and interest in our work!

Yes, you understood our approach correctly and this is the main limitation of all our estimations (rather than calculations) as all of them are based on other peoples work. And still many things have never been analysed and are based upon assumptions (no one has covered a pit latrine and measured the gas emissions for example). In the recommendations we will spend some time on future research possibilities to fill these gaps but unfortunately we do neither have the time nor the finances to do it ourselves.

To your comments:

1) Yes, we meant UDDT while speaking of Ecosan and have changed that.

2) We will most likely not go into the intentionally intended depth of each system as to include different cover materials as the project is much more complex than we thought and we are running out of time – but for future work a very interesting point!

3) As the focus is on informal settlement in urban poor we did not include this option but again a very interesting one for future work.

4) We do not have a link in form of an URL to clean team chemicals but did analyse them in depth and include them into our spread-sheet as they play an important role and are questionable from my personal point of view (Lars Pelzer).

5) Yes, taking the LCA (Life Cycle Assessment) approach we do include production, transport and operation of different materials.

My best,
Lars Pelzer (saniman)