BlakeMcK wrote: Hi All,

Elisabeth

• The project in Cambodia is the Sanitation Marketing Scale up (SMSU) project. It was an approximately 7 million dollar project awarded directly to iDE and funded by 3 donors - BMGF (about 4 mil), Stone (2.1 mil), and WSP (about 600K)

Dear Blake-

Thank you for giving so detailed responses to the questions in this forum. For clarification I ask about the cost of the toilet. You informed that iDE will receive 7M USD for the project including 4M from BMGF, but Elisabath also asked about the program:

> Date: May 2012
> Purpose: to significantly increase sanitation adoption and accelerate hygiene
> behavior change among rural poor communities in Vietnam and Cambodia.
> Amount: $10,892,820

This program is to provide subsidy for sanitation. Is part of it included in the 7M USD? The market ignition is impressive, but how much of the cost of the toilet is subsidized? Donors provided 7M USD to iDE, beneficiaries paid 4.5M USD, and the Gates paid (some portion of) the additional 10.9M USD in subsidies? How is it allocated over 100.000 toilets? Or better to ask, how many toilets of the 100.000 received full or partial support from iDE? If it cost 200+USD /toilet then the design may be to expensive for other countries.

Hi,

I have been asked by Elisabeth:

I thought the 100,000 latrines built ("Easy Latrine") were single pit latrines, but in your last post you said you are now going to twin pit latrines? (You said: "The current approach is to install a second pit, and seal the first one"). I am confused now: Is a significant proportion of the 100,000 latrines in fact twin pit latrines?

Answer:
The Easy Latrine is designed to work either as a single pit or a twin pit. It is up to the customer, so both options are included in that 100,000 count. The majority of customers initially buy a single pit initially and then add a second pit if/when the first is full, simply to spread the cost out.

Hope that helps

Blake

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Note by moderators: This post was made by a former user with the login name BlakeMcK who is no longer a member of this discussion forum.

Hi All,

Sorry for the lack of response from iDE - I just returned from vacation. I am going to do my best to respond to the relevant points brought up in my absence, but if I miss something please just remind me.

Joe asked:
Do you have funding in place to empty these 100K latrines in 8 years time? Not currently. Of course we are looking at lime and keeping our eye on other potential solutions (I personally am excited about the pit excrevator). The key for iDE is that this must be a market-based solution. So once an appropriate technology is identified, we will need to develop a profitable/sustainable business model around that tech/service that is affordable and desired by our customers. This inherently requires more start-up time/investment at the beginning - but if successful can scale quickly (we hope). Of course, iDE does not view itself as the only organization with a role here. We are not yet waste treatment experts - so we are looking for good partners that are innovative and support market-based approaches to explore this challenge with. Ideas are welcome of course.

Elisabeth

• asked bout our relations with Gov. Yes, the Cambodian government has been actively engaged in our sanitation work since the beginning. Currently, sanitation is not a huge priority for them and they are happy with the progress iDE and others (WaterSHED) are making. So the government is supportive of our work but getting them to prioritize sanitation is a challenge and honestly not one that falls within iDE's scope. Perhaps a good place for the World Bank or other institutions that influence policy to step in? Something we would welcome of course. That being said, I do agree with Florian that iDE has a role in this challenge but is not the only actor. Getting the gov interested in addressing pit emptying/waste mgmt./waste treatment would be a huge victory.
• Thanks for the suggestion to look at Dave Still's work. I have already added it to my to do list and it seems very relevant.
• Yes lime is very cheap and easily available in Cambodia. This was a key reason we decided to explore lime as a waste treatment solution.
• The project in Cambodia is the Sanitation Marketing Scale up (SMSU) project. It was an approximately 7 million dollar project awarded directly to iDE and funded by 3 donors - BMGF (about 4 mil), Stone (2.1 mil), and WSP (about 600K)

Heike

• You mentioned that 'cultural not accepted' is not necessarily a valid point. I simply have to disagree in part. Of course people often choose a solution based on what they know, and new innovations can be accepted if introduced properly. However, I still think there are some cultural things (wipers vs washers, squatters vs sitters, etc.) that we don't want to change. I personally think it is not our job to force cultural changes on people but instead to design solutions that meet their needs, desires, culture, etc. Furthermore, if we do strive to change cultural acceptance of these things - we have quite a challenge ahead of us with 1 billion people OD'ing from various cultures in various countries.
• You also mentioned that market studies can shape input - and yes this is 100% true. That being said, iDE tries very hard to conduct our market/user research in a way that does not steer the conversation. We use the Human centered design process that focuses on using empathy and conversation to truly understand a user's situation and his/her needs, wants, desires, and constraints. So we don't ask do you like toilet X or Y - we ask 'what bothers you about your current toilet (or ODing)?' or 'what features are important to you on a latrine' or 'what motivates you to purchase a product.' We really strive for open ended questions. So of course this is not perfect, but just to point out that we do our best to remove any bias or steering of conversations and really get a sense of what the customers want, need, and will pay for.

Florian

• You asked about our choice of one toilet option. You make a great point - market approach is about competition and options. I agree completely. We decided to promote 1 toilet option initially because (i) having too many options can sometimes lead to decision paralysis where households feel overwhelmed and thus don't act at all, (ii) because investing in too many options early on can result in marketing/promotion efforts losing focus or becoming diluted, and (iii) simply because budget was limited. You are correct that other options are needed, specifically for flood prone regions. We have conducted research to explore a solution for these 'difficult environments' but honestly were not able to develop a solution that was affordable or viable from a market-based perspective. More work needed here for sure. Also, I do agree that in the long run multiple product options is the goal. We see our role as catalyzing the market - demonstrating to businesses that working in sanitation can be profitable if you address customers' needs and wants. So we are open to other products being introduced, have seen some businesses innovate themselves, and are hopeful that the market will only become larger and more divers.
• Sludge management - yes, this is an area we have not solved. The current approach is to install a second pit, and seal the first one, as Dave described below. It is not ideal at all but is where things are currently. We agree that sludge management is essential and are exploring this area as much as possible. Once again - we also are looking for partners with relevant experience to explore this challenge with.

Dave

• Thanks for the info on the pour flush program in SA. Your learnings are highly relevant - especially around user insights, pour flush latrines, vermiculture, and groundwater contamination. I will study up on your project and possibly reach out in the near future.
• Also thanks for your thoughts on pour flush not being a total sanitation solution - I agree. Its a stepping stone for sure - but a good one in my mind

Gen

Just like to say I really liked your point "Rather than try to change their preferences, iDE reverse-engineered a toilet to meet their budgets. And similarly, they're working on reverse-engineering a FSM solution that accommodates these latrines." I think this captures a lot of our thinking. We are looking to reverse engineer solutions that are desired by customers, feasible in the context, and have viable business models. It can be a slow process, but hopefully we (or other groups) can make a breakthrough in the FSM side of things.


Wow - my fingers are exhausted. Hope that helps.

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Note by moderators: This post was made by a former user with the login name BlakeMcK who is no longer a member of this discussion forum.

As a former (briefly) iDE-er and in my best effort to not be biased, I'd like to quickly commend iDE for its progress in 100,000 latrines. They have demonstrated the ability to increase improved sanitation coverage and demand and are committed to addressing the FSM issue. It sounds like what Blake is saying that hydrated lime is one of many possible options, and the ideal scenario would involve exploring as many of these as possible. Alas, funding is not infinite.

I think what has not been discussed is the inherent social value of having a latrine in the first place; they provide privacy, dignity (particularly for women)and convenience regardless of their health benefits. Cambodia is a water-washing culture. I think you'd be very, very hard pressed to find someone willing to use paper. iDE invested heavily upfront in the design of their Easy Latrine, which was based on users' preferences. A pour flush was aspirational and a must-have for even the poorest households. Rather than try to change their preferences, iDE reverse-engineered a toilet to meet their budgets. And similarly, they're working on reverse-engineering a FSM solution that accommodates these latrines.

It's not ideal that the FSM issue isn't solved, but having heard suggestions that the sanitation coverage would have increased this way anyway, isn't it a moot point? A solution is needed and various organizations, including iDE, are working hard to find one as quickly as possible.

That being said, given they've developed a $40 latrine design, I think we can fairly credit iDE with their 100k sales; a product this cheap did not exist on the market beforehand (most options were found to be $150 minimum). Latrine coverage would certainly have increased independently, but iDE footed the bill to make a product accessible to households who could not afford a latrine before; this undoubtedly contributed greatly to the increased coverage.

During the Pol Pot regime, the country became decentralized; families were forcibly removed from the cities as the Khmer Rouge attempted to create an agrarian society. Dry pits were built in these rural compounds and shared by many living in abhorrent conditions. Again, Cambodians typically are water-washers, not just the Muslim communities.

Interestingly in Cambodia, there is a lot of water (and iDE trains its producers to instruct households to place the latrine at least 15m from a water source) -- and so many of the challenges they face are dealing with high water tables, flood-prone zones and floating villages. They have several projects exploring different technologies up and running as they work to find solutions for regions/conditions where the Easy Latrine is not an option.

While infographics can be showy and just touting the numbers, at the end of the day iDE has made extraordinary progress and deserves an attention-grabbing, get-the-word-out graphic or two. They make information accessible to non-sector folks and clearly (!) spark lots of conversations.

Hi all

Five years ago I was asked by Jay Bhagwan of the WRC in South Africa to investigate the feasibility of pour flush as a sanitation option in South Africa. Initially I was rather sceptical, as pour flush is known as the basic sanitation option in countries where people are washers rather than wipers, and squatters rather than sitters. For a long time now the VIP has been considered the basic sanitation option for Africa. Properly designed, built and maintained, a VIP does make a big difference and it's big advantage is that there is nothing that can break or block.

We came up with a pour flush pedestal which looks much like a normal toilet except that it is more funnel than bowl shaped. This we found flushed well on as little as one litre, even with toilet paper. If newsprint is used then sometimes a second flush is needed. We have found that the waste will travel quite long distances even at flat grades on this minimal flush (17 metres at 1% is the most extreme we have tried - that was not really by design, but it worked anyway).

We and collaborators elsewhere in SA then installed 30 of these in the field and have been monitoring them for the last four years. Their performance has greatly exceeded my expectations. We have found blockages to be very rare and easily cleared using a piece of flexible pipe or something like that. The water seal and the fact that you do not look at the contents of the pit when using the toilet are a great positive, which I believe is something which makes this a readily marketable product. Yes, some water is required for flushing but that does not have to be potable water - users can save their wash water and use that. An average family will only use 30 litres or so of water per day for flushing.

The advantages over VIPs are the following:

1. Users do not use the toilet for solid waste disposal, which is common with VIPs
2. The pit filling rate is about half that observed for VIPs (partly due to less trash in the pit, but the added water helps too)
3. No smell, no flies - let's face it, even a good VIP has some of both
4. The pits are much easier to access and to empty than is the case for pit latrines, where the pit is under or partly under the superstructure
5. Switching to a second pit is easy, which means that the sludge can be left for some years before it must be emptied (how long will depend on leach pit design and number of users, but four or five years is achievable easily enough)
6. As long as there is no cistern and no plumbing, then 24/7 leaks can't happen so no water is wasted.

One of our manufacturers here, Envirosan, have done a lot of development work and are now making moulds which will enable them to produce an injection moulded pour flush pedestal that can be converted to a low flush unit with a cistern. The low flush conversion will of course negate advantage #6 above, but it will be in demand, especially for institutional use. Envirosan expect to be producing units from August this year. This will help with affordability as all our R&D work has been using fibreglass which is good for experimenting, but it's too expensive for scale application.

For those of you who do not know, South Africa is different from most of the world in that we have top down delivery of free basic services to those that can't easily afford services (and some that can). The disadvantage with this approach is that people are not making choices for themselves and paying for things with their own money (as in the Cambodian case discussed in these posts). I am not sure where pour flush will go from here in South Africa. It might get incorporated into government service delivery programmes, where it might be a success, or perhaps people will complain that it is a second class flush toilet. They might however see it as a step up the ladder towards flush toilets, which are universally aspired to. If the pedestals become available through the market we might see people using their own initiative and own money to retrofit pour flush to upgrade their pit latrines.

Regarding the criticism that pour flush is not a total sanitation solution (like some form of ecosan toilet), I would say the following:

1. There's nothing to stop you combining pour flush with UD, if that's what the users want
2. You can perhaps combine vermiculture with pour flush(we are planning to look into that)
3. It may not be a total solution, but from an FSM point of view it's so much better than VIPs (easy to work with twin pits, easier to empty, slower sludge accumulation rates) that it is real progress.

Regarding switching between pits, I believe elsewhere there might be products which make this switch very easy and reliable, but we don't have them here. We have had trouble with blockages in the splitter box and for now I prefer not to use a splitter box (like you see in the Sulabh design). We just use a dedicated pipe to each leach pit and switch manually behind the latrine. It takes a few hours, but as this only has to happen once every four or so years, that doesn't seem too onerous.

Another issue might be groundwater contamination. We have a research team here which has been monitoring leachate from pour flush latrines in worst case scenarios (including steep slopes and flooded pits). They aren't picking up anything dramatic, or very different from pit latrines which they are also monitoring. I believe this is because soil is a very complex ecosystem and is well suited to containment and processing of faecal sludge. I am not advocating that potable water wells should be sunk close to on-site sanitation systems, but I do think the whole issue of groundwater contamination by on-site sanitation is somewhat overstated. Another experiment I am involved with used pan lysimeters to collect all the leachate that seeped out of a thick layer of buried WWTW sludge. The lysimeter is located some 500 mm below the sludge, with soil between. After one full wet season only 0.004% of the phosphorus contained in the sludge had leached out, and 0.2% of the nitrogen, and this is very close to the sludge. Other work I have done indicates that within a few years the nitrogen levels in that sludge will be no different to the surrounding soil. If it doesn't leach out, then where does the nitrogen go? The only answer I can think of is that it returns to the atmosphere through the agency of soil bacteria by denitrification.

I am not saying that a heavy and continuous nitrate load (think concentrated cattle, think high use densely spaced latrines) will not increase nitrate levels in the ground water. However, from what I have seen so far I don't think old sludge from disused VIP or pour flush latrines if left in-situ or buried nearby has any significant effect on groundwater.

As for pathogens, these may survive for more than four years in a disused vault - I am not sure. What I have seen in our trials is that 3 years after faecal sludge was buried in soil there were no viable Ascaris left. It seems that the very complex ecosystem found in soils is good at breaking down even Ascaris.

hoffma wrote: But unfortunately it seems that the reality does not correspond with “sanitation coverage”; less with “sustainable sanitation”;
Heike

Hi Heike,

I agree in that toilet marketing alone cannot really be called sustainable sanitation, it's just one piece of several pieces needed to come to a comprehensive sanitation system in the country.

But then, this forum is full of discussions on design details of specific treatment technologies, on tiny research or pilot projects, etc., all quite far from being comprehensive scalable solutions.

I think it's fine to have these discussions, but then we should also be happy to discuss sanitation marketing, eventhough appears not (yet) to be a full solution. Acutally I miss very much discussions on approaches like the one used by IDE, so I'd be sad if the that opportunity gets lost in talks about technicalities like lime treatment (thanks for separating this one).

Ok, but then when talking about the IDE approach as such, I think I quite agree to some of the critisms already raised.

I was also wondering about the focus on only one toilet option. If the ambition is national scale, the answer most certainly can't be one size fits all. Just offering one single product doesn't feel like a real market approach, does it? For example, what for those that do not have easy access to water supply, that need to carry water from a certain distance. They might be very well interested in a dry toilet, would it just be marketed in the same way as the pour flush toilet.

Now for the sludge management, if this is really a problem depends much on the setting. In many rural areas the impact from sludge or pits on the environment is not really a problem. In such situation, we don't really need a public service for manageing sludge. The biggest problem is then, what do people do when the pit is full? Are they capable to install a second pit, are they motivated enough to remove the dried sludge from the old pit? Or do they just wait for the next NGO coming along and build the next latrine? I also agree that when marketing toilets to people, something should also be offered for that scenario. The IDE approach, from the bits I read so far (as usual, I need to do more reading), seems indeed laking the answer for this.

In situations with more dense settling, sludge management will become an issue and then public structures are needed. This is when sanitation marketing can't provide the answer alone.

Best, Florian

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Note by moderator (EvM):
See "spin-off" discussion from this topic here:
forum.susana.org/forum/categories/142-up...m-ide-cambodia-topic

Hi, as I mentioned there are good experiences with pour flush toilets in Peru, but it is not the solution for every problem. Peru has areas without water supply and especially in urban situation onsite blackwater treatment can be an economic/ technical problem. I would object about the role of the government for rural blackwater and FS management, the technology was not their decision. This leads me to the question of market studies and limitations to choose the own onsite sanitation facilities.

First of all: In my experience “cultural not accepted” often is not a real argument, people accept what they can imagine, or choose what they think it is expected of them, or what rich people would choose. Market studies are easily to influence (WITHOUT noticing): What would you prefer, a flush (away) toilet or a dry toilet, which will separate the urine and remain your the feces under the seat? EVERYBODY who knows nothing about the latter will choose the flush toilet. BUT, in case of onsite treatment the blackwater will remain as well in the responsibility of the user and the management of dried feces could be safer.

When I explained the first time an UD-Toilet in a traditional rural village in Peru I used pictures of tiled UD toilets with an installed shower. We discussed the possibility of onsite management of the double vault system, urine reuse and so on. During all the discussion one man was circling with his finger dreamy on the picture and finally he asked me: Is there warm or cold water in this shower?
If I had made a market study in this moment, for what would he vote for?

Another village was divided into 16 families for pour flush toilets and 14 families for UD Toilets. After one-year operation, a woman from the pour flush fraction told me: If I had known the UD toilet before, I would have opted for this, because it has more benefits. My neighbor is fertilizing with urine whereas I have to pay for fertilizer, my pit has collapsed (by greywater), the sewage is contaminating my yard and it is returning to my toilet.

How real is a market study? How sustainable is the choice between the very different options and consequences of onsite technologies? AND: up to what point the kind of toilet, the kind of onsite storage and onsite treatment really can be a private decision? Heike

Dear all,

I was going to say exactly the same as Florian: I would also expect that the local government would be the key player for pit emptying and faecal sludge treatment programs (in conjunction with local businesses). I am sure that iDE has already established good working relationships with the local government bodies? Blake, could you perhaps tell us a bit more about that (or tell us in which publication or website of yours we can read about that). Thanks.

Like Florian, I also feel the need to support some of the main aspects of iDE's work here: Someone above said (might have been Joe) that there is no point starting a pit latrine building/selling project if there is nothing in place for the faecal sludge management (FSM) afterwards. I think I disagree with that. Yes, in theory it would be ideal if all the pieces of the sanitation chain were in place right from the word "go" to make it truly "sustainable". In practice it may be difficult to set up a proper FSM system when no faecal sludge has been collected yet in a certain region. Building the latrines buys you some time of some years and if those latrines do indeed save the lives of children (which may not always be so clear cut, see our thread on the elusive effect of water and sanitation on the global burden of disease: forum.susana.org/forum/categories/142-up...al-burden-of-disease - excellent discussion by the way, thanks to Patrick and others)), then it would be almost immporal not to build them or not to encourage market forces to sell them if funding is available. At least we would "buy some time".

Now the question is how much time is bought? I.e. how long do these pits take to fill up (same clarification question asked by Heike above).

And another thing, I would say our colleagues in South Africa are already 7 years ahead of anyone else: they - the local governments together with their consultancy and research partners - are busy right now with optimising emptying many, many pits (VIPs though, not pour flush latrines). In terms of pour flush latrines, they are playing catch-up with South-East Asia: they are now also looking at introducing pour flush latrines in South Africa geared more towards the middle class who might shun dry toilets (and also UDDTs) and go for something more closely resembling a conventional flush toilet.

(curious why pour flush latrines are not common in Peru, Heike?)

(by the way, Blake you mentioned the Pol Pot era and dry toilets or pit latrines; what exactly is the connection, what happened? I know a bit about the horrors of the Pol Pot regime but have no knowlege about the issue with pit latrines during that time?)

So in terms of South Africa, there are plenty of excellent publications on what do to with the faecal sludge once the pits are full, and how to get the faecal sludge out of the pit. Look for author Dave Still in the SuSanA library, he is the guru:
www.susana.org/library?search=still (and then filter on the right for country South Africa)

There is a 3 volume report from 2012 on pit emptying and treatment methods.
susana.org/lang-en/library/library?view=...eitem&type=2&id=1712

There are also some recent presentations about pour flush toilets and the faecal sludge in South Africa which were provided here in the forum:
forum.susana.org/forum/categories/21-eve...in-south-africa#8912
and now also here in the library:
susana.org/lang-en/library/library?view=...eitem&type=2&id=2033

Lime treatment does not seem to be an option in South Africa. Instead they mention things like deep row entrenchment of the faecal sludge (with plenty of associated research on groundwater pollution issues), co-composting, pelletisation (see also here the LaDePa process: forum.susana.org/forum/categories/53-fae...-in-ethekwini-durban).

There is also this project in Ghana (BMGF and others are funding this) to develop pellets from faecal sludge for use in agriculture:
forum.susana.org/forum/categories/98-res...e-1-and-2-iwmi-ghana

Lime treatment does not seem to be big in those African countries, but perhaps that's because lime is not cheap there whereas in your project areas in Cambodia it is?
Anyhow, if you have scope to do comparative research, then I think some of these other options (e.g. involving composting and pelletisation) could be worth looking into? Or maybe you have already considered them and discarded them for a certain reason related to the situation in Cambodia?

By the way, in your press release it states that:

This project, called Sanitation Marketing Scale Up (SMSU), takes place in seven Cambodian provinces.
iDE launched a pilot project in 2009 to establish feasibility. The official scale up began in September of
2011. The 100,000 milestone was reached during the scale up period and does not include the latrines
sold during the pilot phase. Total latrine sales including the pilot is 118,000, and counting.

The three-year Sanitation Marketing Scale-Up (SMSU) project is funded by the Bill & Melinda Gates
Foundation and the Stone Family Foundation, and technically supported by the Water and Sanitation
Program (WSP) of the World Bank. The project is supported by the Ministry of Rural Development.

As I often post about grants by the Bill & Melinda Gates Foundation, I am curious how large the grant was and who the grantee is (not iDE directly, as far as I can tell)?

I found this large grant in the public database of the BMGF, but I am not sure if it's the right one:
www.gatesfoundation.org/How-We-Work/Quic...s/2012/05/OPP1048151

Date: May 2012
Purpose: to significantly increase sanitation adoption and accelerate hygiene behavior change among rural poor communities in Vietnam and Cambodia
Amount: $10,892,820

Thanks again for everyone who is taking part in this very interesting conversation. I think we are all learning a lot here. I really appreciate that.

Greetings,
Elisabeth

Hi Florian,
I agree 50%, but for the other 50% I need to understand why to discuss this topic in sustainable sanitation context.
If the FS contains in the Pits for 5-8 years (or perhaps for 2 years) then private onsite FS management could be an acceptable and affordable solution in rural situation. Probably this was the original plan?
But unfortunately it seems that the reality does not correspond with “sanitation coverage”; less with “sustainable sanitation”;
Heike

joeturner wrote: I still do not understand what kind of a plan iDE have for management of these facilities. Do you have funding in place to empty 100,000 latrines in 8 years time?

Why does IDE need to empty 100,000 latrines? They are not the government, they are not a service provider.


To put it simple: sanitation has a private and a public end. Private people install and use toilets, but if waste from these toilets threatens public health and environment, public systems are needed to take care of that.

Working with people to make them want to buy toilets, and with businesses to establish a working supply chain, requires an entirely different approach as working with governments and adminstrations to set up functionning public services.

I find nothing wrong when an organisation like IDE choses to focuss on one end, even though obviously progress on the other end is also needed to solve the whole situation.

I find IDE's achievments extremely praiseworthy, they seem to be successfull in an area where so many tradtitional donor funded projects have failed (and wasted huge amounts of money) with supply driven approaches (e.g. the "latrinization" projects mentionned above ).

Time for a positive comment after all this critisism here, I thought

Thank you Heike.

This is the point:

By the way, the difference between “access to an adequate sanitary facility” and “sanitation coverage” is the adequate treatment and disposal.

Collection of faecal waste is not treatment unless there is storage for considerable lengths of time without further faecal additions. Even then I have some doubts as to how safe the sludge is.

I still do not understand what kind of a plan iDE have for management of these facilities. Do you have funding in place to empty 100,000 latrines in 8 years time?

Hi Blake,

sorry, but I did not get the point that you were talking about Pour Flush Toilets – I would never force (dry) UD toilets when other solutions are possible AND affordable.

In case of Pour Flush Toilet:

- “possible” means: i) people always have water for flushing. ii) BLACKWATER and FS are TREATED(no/low risk). 5-8 years in the Pit could be an option, but it means deep pits, good absorption capacity of the soil, sufficient distance to ground water and to springs or wells and no risk of storm water or inundation (pit flooding).

- “affordable” means: Costs of water flush systems with onsite treatment for blackwater are higher as for dry solutions. I do totally agree that from a user point of view pour flush toilets are an attractive investment and own payment is a strong argument to choose the preferred facility (when there is no/low contamination risk).

I know good examples for Pour Flush Toilets in Peru; for blackwater treatment are used double Pit systems (Sulabh), each Pit can be used about 2 - 3 years (4 - 6 years until emptying). There are some risks if people begin to connect the greywater (kitchen, shower) with the Pit, because the exfiltration will saturate faster.

I wonder why did you not published about the technology used. What do the user pay with 41,50 USD? Why the discussion about the lime? From my knowledge, the pits are dried out and when the second pit is full the first is emptied out. HOW and WHERE do you want to apply lime?

Looking for an answer I found here: forum.susana.org/forum/categories/53-fae...mit=12&start=12#9077 “Typical sludge in Cambodia has a lot more water due to flushing and washing… The typical problem is the filling up of pits with water, from users and infiltrating rainwater. Hence our decision to treat the liquid phase of the sludge. Users need to empty frequently to deal with this water, rather than the solid sludge accumulating at the bottom of the pit, which happens at a much lower rate.”

It is confusing, because you answered: "these latrines do contain the waste for 5-8 years until the pits fill up"; but in case of frequent emptying we are back to the initial concern: how can private onsite management of untreated/no stabilized fecal material be sustainable? By the way, the difference between “access to an adequate sanitary facility” and “sanitation coverage” is the adequate treatment and disposal.

Heike