Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

  • goeco
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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

Michal,
I would be surprised that the carbon component of urea is 40% of the total carbon in our excreta. Feces are relatively high in carbon and the C/N ratio is pretty good for decomposition. Add pure urine and the nitrogen to carbon ratio goes through the roof.

Everybody,
The point I have been making all along is that with some simple modifications the decomposition can be converted from anaerobic to aerobic. Because there is flush water diluting the urine, there is no need to divert urine for aerobic decomposition, this is achieved via wet composting process. Aerobic conditions are suitable for worms and microorganisms, whereas anaerobic conditions generate methane which doesn't allow the worms to colonise.

There is no aerobic condition inside pit. It is completely anaerobic.


The other important point is that what causes anaerobic conditions is excess of water. Simply put, insufficient percolation. What happens with standard pits is that only once the influent is diverted do the conditions adjust (the pit drains sufficiently) and the worms become active. I am trying to explain a solution that allows worms to be active the whole time, significantly reducing the rate at which the pit fills. Key to achieving this is increasing percolation area to ensure that liquid influent does not exceed liquid infiltration.

Pawan, a wider shallower pit has a larger surface area in the bottom of the pit. Wider and shallower vastly increases soil surface area for water to infiltrate. If the soil has poor infiltration an additional soakage trench is necessary.

For the growth of Earthworms, it is quite difficult to maintain suitable environmental condition inside twin pit, as there is complete anaerobic condition.


Using your design criteria as per "Technical options for on-site sanitation" you are correct. Would you be willing to test the modifications I have explained above? I am more than willing to work with you on a demonstration unit.

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Dean

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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

hi all,
great stuff - the new SATO connector for twin-pit as well as Dean's suggestion to have aerobic digestion in twin-pits!

please note (and correct) that we have now two threads with the same name (New SATO Connection System for Twin-Pit Pour Flush Latrines), one starting with post 22105 and another starting with post 22244. I propose to change the title of the second thread to 'Twin-pits: use them with aerobic or anaerobic digestion?

still enjoy reading discussions, no time to contribute, sorry!
ciao
Hajo

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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

Dear Hajo,
You're right about the wrong thread title. I have corrected that now. Somehow the system went back to the original thread title even though I had split it off into a new thread which I had called: "Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?".
Hopefully it will now keep the new title and not revert back.

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Elisabeth

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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

I'm not yet ready to let this subject lie unresolved, with so many pits continuing to be constructed. What a big mistake. I will reiterate what I have been saying and add a diagram. Before that however, I'll quote from a BGS report (thanks @stevensugden ):

Open defecation is practised by over 600 million people in India and there is a strong political drive to eliminate this through the provision of on-site sanitation in rural areas. However, there are concerns that the subsequent leaching of excreta from subsurface storage could be adversely impacting underlying groundwater resources upon which rural populations are almost completely dependent for domestic water supply... increasing faecal contamination of groundwater-derived potable supplies is inevitable across the country as uptake of onsite sanitation intensifies. Communities need to be aware of this link and implement suitable decentralised low-cost treatment of water prior to consumption and improve the construction and protection of new supplies.

Pits, whether single or twin chamber, have got to be the worst of the lot in terms of groundwater contamination. Yet with some simple design changes anaerobic digestion can be converted to aerobic, lowering costs, capacity and emissions. Further, by making the "pits" wider and shallower, contamination of water tables would be significantly reduced.



cheers
Dean

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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

As I said on the other thread, why do we still build pits?
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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

I understand where your notion is coming from, but when it is already hard to convince people to stop open defecation and build a toilet in the first place...

And for various mostly unrelated reasons it is usually also advisable to stop using the highly polluted shallow wells for drinking purposes.

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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

It is about education, time and money.

Forgive me, because I don't know what processes you use. In our Indian villages we work with our 'users' before, during and after UDDT construction. Even when we are not around so much we form Village Development Committees to gently use peer-to-peer pressure to encourage continual adoption. In our seven 'targeted' villages we have an adoption rate averaging at 90% after four years. Women, girls and boys are all over 90% and it is only men that lag behind, for all the reason we know about. It is interesting that the young boys generally follow their mother's lead on toilet usage and not their father's. However, after each rainy season fewer men return to OD.

What we are now looking at is why we don't get 100% usage among women (excluding older people who are set in their ways) and it seems those who aren't toilet users are generally on the margins of village community life.

It is about take the educating people in why to use a toilet and how to use a UDDT, spending the time to keep pushing the message and having investment to pay for the education/time and construct long-lasting and better quality toilets that everybody is happy to use.
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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

But 50,000 pits per day are currently being constructed under the Swachh Bharat Mission. Thats a lot of pits to contaminate groundwater, replacing open defecation (and its problems) with pits (another set of problems). Great that they're resolving the fecal sludge issue with twin pits... some countries don't seem to have even got that far, but is it really about education, time and money... or is it about decision makers who are not adequately informed when decisions are made? I think what is required is a paradigm shift towards requiring excellence and innovation.
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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

DavidAlan wrote: It is about education, time and money.

Forgive me, because I don't know what processes you use. In our Indian villages we work with our 'users' before, during and after UDDT construction. Even when we are not around so much we form Village Development Committees to gently use peer-to-peer pressure to encourage continual adoption. In our seven 'targeted' villages we have an adoption rate averaging at 90% after four years. Women, girls and boys are all over 90% and it is only men that lag behind, for all the reason we know about. It is interesting that the young boys generally follow their mother's lead on toilet usage and not their father's. However, after each rainy season fewer men return to OD.

What we are now looking at is why we don't get 100% usage among women (excluding older people who are set in their ways) and it seems those who aren't toilet users are generally on the margins of village community life.


Money (and to a lesser extend time) are definitely important factors, but I very much doubt it is about education.

While I am not working in India, the project I am involved with in southern Nepal is probably quite comparable. Through our promotion efforts (a sort of CLTS, but mostly just intensive promotion, some limited (planned) subsidy for the most vulnerable and the looming threat of government issued sanitation cards that are used to withhold services), we have reached something like 80-90% household toilet coverage (but with toilets of really vastly different quality and sustainability...).

But similar to the numbers/reasons you state, it all breaks down if you look a bit closer at the numbers. Some areas have a much lower coverage (margin of villages where open defecation is easier), but most importantly the actual usage of the toilets is below 50% when looking beyond the main recipients of the promotion messages (women at home during daytime, but men and elderly have with especially high OD rates) and/or consistent usage (i.e. toilet use is a lot higher during rainy season as OD becomes a bit difficult due to flooded rice fields etc.).

Interestingly our rather informal survey data also indicates a higher number of available hand-washing places and (self-reported) hand-washing behavior at critical times in areas with low toilet coverage, indicating that education really isn't the main issue (not all that surprising after years of NGO hygiene promotion). Ironically this figure is lower in places with higher toilet coverage but low actual usage... which might be a data artifact, but would mean that the pure construction of toilets is somewhat counter productive...

Maybe I am just looking at similar numbers less optimistically then you, but what I see is that most people are not really convinced of the actual benefits of (consistent) toilet use despite a lot of "education".
Given the strong social/cultural (and economic) reasons for only building toilets at a considerable distance from the household and with a low quality of construction and low maintenance/cleanliness, I can actually partially understand that the use of such toilets isn't really much more convenient or less disgusting than open defecation. The distance issue explains by the way why despite strong external incentives to build toilets the coverage isn't nearer to 100%... these households simply do not have sufficient land or live in crowded conditions that would only allow building a toilet directly attached to the house (which only very few households seem to be willing to do and if so only with a significantly more expensive modern/aspirational design).

The entire question of (dual) pit-latrine or better alternative technology that reduces ground-water pollution really doesn't even enter into the picture under such conditions, and any design that would require more land and/or more active engagement with excrement of some sort would be actually counter productive in convincing people to build (and use) toilets.

goeco wrote: But 50,000 pits per day are currently being constructed under the Swachh Bharat Mission. Thats a lot of pits to contaminate groundwater, replacing open defecation (and its problems) with pits (another set of problems). Great that they're resolving the fecal sludge issue with twin pits... some countries don't seem to have even got that far, but is it really about education, time and money... or is it about decision makers who are not adequately informed when decisions are made? I think what is required is a paradigm shift towards requiring excellence and innovation.


Actually, often the fecal sludge issue is not solved at all, as in my experience many people find it more convenient to directly connect both pits. I guess they reason that they thus have to deal with the question of emptying the pit even less frequently? At least the actual safety of emptying doesn't seem to really enter into the picture for them as they either don't seem to care or are expecting to be able to hire someone else to do it for them? Not sure... this is rather anecdotal evidence from various informal interviews I did with local toilet owners.

I actually think that the decision makers here in Nepal intuitively know most of that, but that there is regardless of that a strong incentive (due to external pressure, racial/caste prejudice and urban/rural social divisions) to continue pushing for building toilets that aren't much used and which do pollute the groundwater.

For me the needed paradigm shift shift is actually accepting a certain level of rural / low population density open-defecation (with some mitigations in place) but totally rethink the approach to housing and sanitation in densely populated rural growth centers that are most negatively effected by the unhygienic conditions. If all the money and effort that is currently wasted of building some unsustainable toilets in remote areas was used to positively (i.e. without all the prejudice and coercive pressure) engage/subsidize house-owners in these dense villages to build houses with piped water and attached modern sewered toilets (something most actually seem to like, but can't afford), the actual outcomes in overall hygiene and happiness would be much better.

Edit: of course the latter approach would also require a serious effort to solve the fecal sludge and waste water treatment issues; and not just dumping it all in the nearest river like common in the cities here in Nepal. But compared to solving open-defecation and pollution of groundwater from pit-latrines everywhere, this is really only a minor technical/financial question.

Edit2: to avoid being stigmatized here as being in support of "conventional" sanitation solutions and talking down UDDTs etc. These are of course a great solution in rural areas where people actively engage in the idea of reuse without any social stigma attached to it and container based sanitation can be the only viable solution is densely populated but geographically/climatically very challenging conditions, but the Nepalese lowlands and I guess much of India, Bangladesh & southern Pakistan (where OD is currently most prevalent globally speaking) are in my opinion far from ideal locations for such concepts and properly used twin-pit latrines and simplified sewers an not great but mostly acceptable option.

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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

Maybe I am more optimistic, but talking to the people we work with there is a real 'hunger' to have and use toilets. Our experiences just differ.
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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

Dean wrote "Thats a lot of pits to contaminate groundwater, replacing open defecation (and its problems) with pits." (see forum.susana.org/251-pit-latrines-e-g-si...iples?start=12#24218 )

Implementing pit toilets in high water table / flood affected areas has serious consequences due to ground water contamination. Such risk is adequately mentioned in the book - Technical options for on-site sanitation, released by the Ministry of Drinking water and Sanitation, Government of India as well as in other books on the topic. However, there is no regulation / control on implementing such toilets in India. If the situation continues, the rural areas may be made Open defecation free (ODF) in near future, but the community health problem due to ground water pollution may be more sever than getting benefit from ODF.
I had a discussion during a few days of my travelling in the Bihar state, with senior concerned officers of the state government and officers from some districts having high ground water tables. Officers are normally aware of the problem but they don't have any guidelines / regulation to select appropriate technology,for high water table areas.
Under a project funded by the WASTE, The Netherlands and FINISH India we have planned to prepare a document with sustainable technology for such areas. we will demonstrate a few units of household toilets in high ground table areas / flood affected areas in March/ April in one or two blocks in Darbhanga District , Bihar. State government may take up the technology under its scheme for implementation at larger scale.

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Re: Twin pit pour flush latrines in India - is it timely to call into question the design and operating principles?

Hi Dean,
I am very interested in this topic and am writing my thesis on a related topic to do with the miss-use of pit latrines.
in reading the whole thread it seems the answers are being taken off topic by terminology... You talk about the paradigm shift needed and you are absolutely right, but this needs education, which is where people are going off topic to mean education in a public health messages sense, so perhaps it would be better to refer to this as Technical Capacity?! It is the decision makers and information spreaders who need their knowledge increasing of the options and benefits of alternatives. Then the knowledge can trickle down to communities at large. Have I understood you correctly?
Regards, Jemma
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