Dear Mr. Andrew,

Thanks for clarification. In Sindh, no health impact assessment has been conducted. Simple ordinary types of latrines are used. The U shape design of pot is used, built on the floor, used in squat position, which is cleaned by sweepers daily.

Perhaps, you may consider developing a small booklet of your interesting system. As James Harper says, it is interesting design indeed!

Regards,
F H Mughal

A very interesting design, Andrew! Thanks for sharing the details.

Cheers,

James Harper

Dear F H Mughal,

Perhaps we have misunderstood each other about what was meant by “clean/de-sludge”.

With the design used the latrine pan & all exposed components can be cleaned regularly as users desire (i.e. daily). People in Cambodia also have a strong preference for clean & tidy latrine facilities.

Desludging (removal of accumulated fecal sludge) is something that only needs to happen once every few years depending on system usage. This system is just like other septic tanks and pit latrines in this respect. Desludging is not something that households do on a regular (i.e. daily) basis.

I would also like to clarify that while EWB conducted the assessment & report on these latrine installations, we were not involved in the design or construction phase – this was done by Maltester International before EWB became involved. As such we are not in a position to immediately conduct a health impact assessment, but if you can share details of previous health impact assessments you have been involved with that would be appreciated.

If you can share details of the latrine designs you use in Sindh province I would also be interested in these.

Regards,
Andrew

Dear Mr. Andrew,

Thank you for your drawings and elaboration of the system.

You say:
To clean/de-sludge the pit or pipe the components need to be disassembled. This involves breaking the mortar holding the lid or pipe in place to get access (or cutting the pipe). The mortar would then need to be replaced/repaired afterwards. While this is inconvenient . . .

That aspect will be a bit difficult for people to accept. It will discourage people from using it. In Sindh, because we are Muslims, the latrines are cleaned daily.

I humbly suggest that, you sit down with your team, and develop some other alternate easy and convenient method. Also have have a health impact assessment conducted.

Regards,
F H Mughal

Hi F H Mughal,

Please see more detailed drawing attached, provided by Malteser International. The thinner blue pipe going straight up from the top of the pit is a ¾” ventilation pipe. The larger blue pipe that bends out the side of the pit and then travels off horizontally at ground level is placed in a gravel-lined infiltration trench for soak-away of the black water.

To clean/de-sludge the pit or pipe the components need to be disassembled. This involves breaking the mortar holding the lid or pipe in place to get access (or cutting the pipe). The mortar would then need to be replaced/repaired afterwards. While this is inconvenient it is very important that the systems are well sealed to prevent any leakage during times of flooding, or during the dry season so that there isn’t any seepage at joints which will smell unpleasant, and using cement & mortar is by far the most common latrine construction approach used in Cambodia.

The toilet seat can be a placed at any height above the ground, but should be elevated above the maximum flood level, and be a minimum of 250mm above the top of the latrine pit (so that the toilet can still be flushed when the pit is full or flood-waters are high). In houses that are on higher ground the toilet pan is only ~0.5m above the ground, however in others where the floodwaters are deeper the toilet is elevated 2m+ above the ground.

In Sindh Province is it possible to elevate the toilets to 0.5-1m above the ground so they do not get flooded when the rains come, and therefore remain use-able during times of flooding?

When the water recedes the latrine/pit continues to function as per normal. If a pit needs desludging (which occurs every 2-4years) this should be done in the dry season. I do not have a health impact assessment for this specific site, however I have attached a research article from Central America that is about the health impacts of poorly constructed latrine pits in flood prone areas.

Have you previously conducted health impact assessments on sanitation projects similar to this? If so I would be interested to know more details. Would you be able to share the findings and also the methodology you used to conduct the health assessment?

Regards,
Andrew Koolhof

Dear Mr. Andrew,

In the rural areas of Sindh province, Pakistan, we have heavy rains (causing flooding) every 2-3 years. The houses get flooded up to knee height, sometimes more. The toilets get flooded as well. Most houses are of brick-mortar, with a few as shown in the photo in your report, but at ground level.

I was trying to have a good look at section 6.3, pp 13 of your report (Technical Features), with the aim of how they can fit in our local context. The sketch is too small to make out a good output - how high is that toilet seat from the ground, what is that blue pipe, how can it be cleaned/desludged, any health impact assessment, what would be the scenario once the water recedes, and so on.

Can you kindly put up a detailed drawing?

Regards,
F H Mughal

Hi Elisabeth, thanks for taking the time to read the report and your detailed response.

Yes, simply put the latrines are similar to normal concrete-ring pour flush latrines with two key differences:
1. They are raised higher above flood level by stacking additional concrete rings on top and sealing these well using mortar/cement paste.
2. The first stack of rings is also sealed at the bottom, forming a sealed settling chamber, and there is a connecting pipe through to either a gravel infiltration trench; or a second smaller ring stack that is not sealed at the bottom for liquid effluent to infiltrate the soil.

This larger and more complicated sub-structure arrangement costs approximately $150USD per installation, as opposed to ~$75USD for a ‘standard’ installation (normal pit latrine), so around double the cost for the larger, elevated design.

The affordability question is a complicated one. This larger option is too expensive for the lowest wealth quintile households (poorest households), but then a ‘standard’ latrine often is as well without some form of support/discount. The larger design is probably within the means of ‘middle-income’ rural households, but a challenge would be ensuring they see & understand the value/reason/advantages of spending more on the larger system, and why they can’t just get a smaller, cheaper system. This would need to happen before larger-scale uptake can also occur. Masons and local businesses would also need to understand the different ‘designs’ or variations they can use, and ideally these designs would be ‘standardized’ in some way to help alleviate quality issues. Some programs subsidies/support larger, more complicated designs such as these, and I think any larger scale uptake of larger and more complicated systems will require significant external support (both capacity building & financial support of some description).

Regarding the water-proofing between the rings this is a good point, and a key quality concern with the design of this (and similar) systems. In the assessment for the report leakage from the rings was looked at and only a few systems had very minor leakage that could be repaired using mortar/cement paste. More generally though, construction quality & the sealing of ring-joins is a challenge and I have heard of/seen other elevated concrete rings that are somewhat porous resulting in ‘effluent seepage’. Applying a layer of mortar paste can stop this, however this is inconvenient. In summary there may be some minor liquid exchange during times of flooding.

A few organisations here are looking at other variations of concrete-ring pit latrines so they are suitable for challenging environments (such as flood-prone areas). Examples include having multiple chambers/pits to create a septic-tank style system, and/or adding a ‘filtration’ stage to reduce pathogen levels.

One of the other key challenges in areas that flood seasonally is to have the latrine pan elevated above the maximum flood level. Otherwise households will revert to open defecation in to the floodwaters when the latrine isn’t accessible. Generally it is also more expensive to build elevated latrine structures.

Regarding container-based systems I do know of some trials that have occurred with these, however in Cambodia there is a very strong aspiration/desire for pour-flush systems. In general concrete-ring pour-flush pit latrines have very wide spread usage and are aspirational in Cambodia and are the ‘norm’ in rural (and often peri-urban) areas. I have heard of a number of eco-san and composting toilet systems that have been tried, however there is very low community acceptance for these. People do not want to have to handle the waste on a regular basis. We think that in the future using the SaTo pan instead of ceramic pour-flush pan would help to significantly reduce the water carrying issue.

You also raise a good point about the pit filling – this is something the sector in Cambodia is starting realise/tackle more. As sanitation coverage (pour-flush pit latrines) has been expanding rapidly in the previous few years there is soon going to be a big need for quality FSM approaches in rural areas to empty all these pits! While the systems installed in the report don’t have a good solution to the FSM challenge, this is something that more focus is starting to turn towards as it will affect many of the households in Cambodia soon!

Dear Andrew,

Thanks for sharing this report here which I read with interest. So the latrines built are like normal pour flush latrines, only that the hole in the ground extends like a storage container to above flood level, i.e. several metres up in the air by using more ring beams.

I wonder what you could tell us about the costs of these kinds of toilets? The report only spoke of the costs of the superstructure:

On average the superstructure cost households 180,000 Reil ($45US) to
construct

Is the cost affordable and do you see any larger scale uptake of these kinds of toilets in flood prone areas?

I wonder if those ring beams where they connect to each other and also where they connect to the ground, would be totally water proof so in case of flooding there is absolutely no exchange of liquid from inside of the raised pits into the flood waters?

With this concern in mind I also wonder if any of the organisations involved had considered alternative options, like toilets that would stay completely above the flood line: container-based sanitation systems (see here on Wikipedia for example: en.wikipedia.org/wiki/Container-based_sanitation)

This would also alleviate the need to carry water for flushing up to the elevated toilets. It would however require regular emptying of the containers, to be carried out by the toilet owners, versus not having to worry about the pit filling up for some years (but when it's full the big questions start how to empty it and who should be in charge etc. So the problem is only deferred, not solved)

Regards,
Elisabeth

Last year, as part of its Sanitation in Challenging Environments project in Cambodia, Engineers Without Borders (EWB – Aus) conducted a survey of households living in an area of Cambodia that is seasonally affected by severe flooding. The households have specially constructed flood-prone-area latrines that were built with the support of Malteser International in response to widespread cyclone damage. The survey aimed to collected information about the user experience and perceptions of the latrines & shelters, any technical issues that may have arisen since construction, and ongoing usage rates. Prior to the project in Siem Reap province, only one household in the village (which has over 100 households in total) had a latrine, and this was washed-out and unusable during times of flooding.

Key findings from the survey include that 89% of the latrines built were still in use 18+ months after construction, and that nearly all the households ‘liked’ having a latrine (even if it wasn’t currently in use). Overall households showed a clear liking for the ease of defecation that the toilet provided (as compared to having to travel into the fields or forest), while the health benefits of having a latrine was probably viewed as a secondary, not primary, benefit.

There was also a significant variation in the number of people using each of the latrines, as in some cases, after construction, additional neighbours and relatives started using the latrines once they became ‘familiar’ with them (one house had up to 10 additional users per day from outside the primary household). The main challenge mentioned by a third of households was the quantity of water consumed by the pour-flush latrines (all households were less than 150m away from a water source, however the elevated nature of the latrines made it difficult to carry the water up to the latrine). Many households indicated dissatisfaction with their current superstructure, which they had had to pay for and construct themselves, and showed a strong desire to improve this as the most important change to their latrine.

The full report with findings is attached.