Dear Laxman,

Water getting into UDDT fecal containers is a nuisance. UDDT toilets will lose their functions and become pit latrines. Raised floor levels and water proof containers and the roofs are the protection for raining water getting into the fecal chambers.

There is a design by use of mesh sacks as holders for the fecal materals. The sacks are suspended inside a container (say, the dustbin), and the liquid permeated down to the bottom, where some earth is placed to soak the liquid.

Dear Tore,

A new technology in dealing with the patrogens in the FM is alleged to have been developed by some companies in China. They heat the fm to 70 degrees centigrade before making compost out of the FM. It is said the cure time is shortened and the nutritions in the manure is retained. I have not visited the factories, but have had conversations with them by social media.

Cheers,

Sam Shan

Hi Tore,
I am just wondering which publication you were referring to in your statement:

I have seen reports of tests done after 6 months on a UDDT and the feces were sterile but no one could say why, The temperatures did not go above 50 so it had to be some combination of other factors.

?
Getting the feces "sterile" seems nearly impossible (unless perhaps with lime treatment, i.e. to kill everything?). Maybe the publication was referring to a reduction in helminth egg viability in particular?

Regards,
Elisabeth

The questions I have are more nuanced.
1. If the temperature is above 20 can the time be reduced and if so by how much.
2. At higher temperatures how long do the temperatures need to be maintained to destroy the eggs.
3. If you achieve higher temperatures ie 40 to 50 for one hour each day how does it take to make the feces sterile? I have read that varying the temperatures stresses the pathogens and they die quicker. Is that so and if so what temperature variations are recommended for die off.
4. I have seen reports of tests done after 6 months on a UDDT and the feces were sterile but no one could say why, The temperatures did not go above 50 so it had to be some combination of other factors.

Thanks Tore and and hajo,
Dear Tore, yes there are information on time and temperature needed, which has been compiled in Compendium of Sanitation Systems and Technologies as follows - “Faeces that are dried and kept at between 2 and 20 °C should be stored for 1.5 to 2 years before being used at the household or regional level. At higher temperatures (i.e., >20 °C average), storage over 1 year is recommended to inactivate Ascaris eggs. A shorter storage time of 6 months is required if the faeces have a pH above 9.”
This is what we followed while designing our ecosan toilets. Now as we have toilets in use, we wish to revisit and see how in practice the situation is different particularly with respect to moisture and pH and see if any additional measures need to be adopted before working on scaling up.

In fecal tests are you looking at potential bacteria count in the fecal matter before emptying? How long will the unused fecal matter be stored before emptying? I assume that the fm will be used as a soil conditioner. There is continuing studies of how long and at what temperatures are required to totally kill all organisms in the fm. I would be very interested in what you find.

dear Laxman,

some few quick comments on the sketch in the previous posting for the UDDT with sandbed:

1. I fear the sand bed can eventually get clogged by fines from the FS
2. the plastic mesh/geo-textile will obstruct emptying the vault with shovel and rake and may eventually get spoilt
3. in areas with high GW table the effluent cannot be drained but has to be captured in a container (like the COMPOSTERA does)
4. if that approach should be followed up further, maybe the plastic mesh can be replaced by a false concrete floor with holes which let the FS drain into the open space below (similar to the technique of the Otji-toilet which has a false floor for the containers)
5. ... and altogether I would rather try all means avoiding fluids getting into the FS (as you indicate by better training and by avoiding leakages from the urine pipes) because having means draining fluids may induce less care by the users about their toilet.

ciao
Hajo

Greeting from Kathmandu this is to share our experience and plan of an initiative to addressing the practical problems related to ecosan toilet that we also discussed.
Actually, in India we (Terre des hommes) have been able to reduce the entry of unwanted water into the ecosan vaults by embedding the pipes that drain out urine and wastewater within the ecocan pan floor and avoiding joints. This we did as we noticed that one of the reasons behind ecosan vaults in this region getting moist was due to leakages from pipes and joints that were laid below the pan floor in the top of the vaults. In addition to this to reduce other misuse, we delivered a longer and more intense software program. We made 209 toilets in Andhra Pradesh and West Bengal states of India during 2011 to 2016 that were all in use and we expect them to be in use now as well. The community for whom we had chosen these toilets liked these toilets because they found it more suitable than the traditional leaching pits as their place were prone to regular flooding and with groundwater sources close by. (Our ecosan toilets are with alternating double vaults).
Our plan now is to revisit these toilets and survey on the use status along with test of the drying faecal matter to provide a basis for scaling up ecosan particularly in areas that are not suitable for traditional leaching pits. As the sanitation coverages are increasing finding sustainable solutions such as by reviving ecosan for such areas (water logged and with high risk of contaminating ground water sources) is necessary to achieve 100 sanitation coverage.
In this we would be happy if you are (a) interested to see and comment on the methodology we have developed for the use-status survey and drying-faecal-matter tests, (b) interested in possible collaboration; or (c) if you may have any suggestions.

Greetings,

To deal with the problem of water getting inside UDDT, I have made this design. In it, the lower two inches of the UDDT vault is like the sand and gravel part of an unplanted faecal sludge drying bed. The excess free water here is supposed to percolate down to the bottom which could then be drained out by opening the washout. Would appreciate in case you may have any remarks.

Regards, Laxman

Hi all,

the Otji Toilet is actually composting partly already in the vault - if the system works well. In Namibia we experience that the solid, once removed from the vault has already to 50% composted. Moisture for this process is sufficiently provided by urine, as our UDS-Bowl divide only 80% of the liquid. Sun driven ventilation is also in place by a huge black metal pipe. But centralized maintenance is important and should not be left to the users as the experience of Haiti has shown. In the case of Haiti it was maybe an additionally challenge that showers were combined into the toilet huts. In this case user education would have been even more important to avoid any input of shower water into the pit. In some isolated cases, we also experienced in Namibia an accumulation of water in the pit. But there was always a reason, like surface water, washing water, shower water or an extensive number of users. To identify the reason usually leads to the solution. As I understand, at the case of Haiti management have just changed that time when problems with the Otji Toilets came up, while the originally implementing agency was discharged.

However, meanwhile we have observed blockages with our UDS-Bowls once in long term operation (struvite?). Therefore we have now changed the urine release from its horizontal 20mm outlet into a vertical 50mm outlet (see sketch attached). We hope, that the 50mm pipe will not again tend to blockages.

Best regards,

Peter

Dear Clint

The reports were intended for main question "Parameters for testing the health status of ecosan..." (see here ). The reports details the development of method for helminths, specifically for Ascaris, and the need for an optimum detection protocol (see Chapter 3 of Report TT356) as the scientific results obtained will inform decision-making. It provides the basis for selection of appropriate technique.

About other things in reply (which seem to be more on design):
In the 1626 Report, it is acknowledged on page i "is not a full EcoSan system" as it does not address recycling and that the system introduced (at that time) would be constantly improved and was designed according to guiding principles identified by stakeholder (read 1st paragraph of page i of TT56).

About the design of this system - look here - www.sswm.info/sites/default/files/refere...nology%20Options.pdf

To put things into context, we are progressing to other systems - it is context specific thing to South Africa as flush-type toilets are viewed as gold standard (another discussion for another time but you can look at www.scielo.org.za/scielo.php?pid=S1816-7...5&script=sci_arttext to get an idea). So my main message was to provide an appropriate methodology as per main heading and not to talk about design features of that toilet.

If you still interesting in venting aspects, I do have data from a study done a while ago. It does mean more graphs and tables. It looked at different venting configurations (ventpipe reduction, extension within a vault, ventpipe wind velocities vs temp, heap temp with and with/o vents). Vane anemometer was used to measure wind velocities and temp measured in vault and heap. The system was similar to the vault design of the system described in my message above but with solar heating panel. That research project was terminated as heap temperature remained the same regardless of configuration. Just email me if you want it: This email address is being protected from spambots. You need JavaScript enabled to view it.. Note: the results are for this design - doesn't apply to everyone else's - they would have to share their data for their system.

Kind Regards
S

Clint, these documents are about VIPs - which are intended to work by dehydrating the faeces not composting. I am also skeptical about whether any significant composting can be occuring in these vaults, but colleagues here have told me in the past that they are not intended to be for composting.

Personally, I don't think I'd do any composting inside a confined space. Pits and vaults might be necessary for collection, but good composting can only be done in a outdoor aerated space, I believe.

I scanned the two reports and found them to be sufficiently full of written words, graphs, charts and one picture of the inside of a vault with plastic bottles and other misc. stuff and a pudding consistency of the pit.

There is not one single picture and/or drawing of the proposed pit/vault design and/or how it is suppose to operate effectively. I can only assume that the vault has absolutely no design for ventilation and evidently easy access for anything to be thrown into the vault that is not compostable.

Even though you are attempting to improve current comingled wastewater discharge practices, my experience is that you do not have an adequate design for the vault to perform aerobically/composting effectively.

Since I copied the initial Clivus Multrum composting toilet design back in the 1970's I have dramatically improved the aeration design of my tanks to insure adequate aeration of the entire composting mass and the ability of using gravity and the floating perforated floor to allow the excess liquids, to include urine, to collect and be evaporated or removed as liquid fertilizer on the bottom of the tank.

The old concept you are attempting to utilize, use one for a while and then shift to another to allow the other to sit, only works if you have proper ventilation.

I would advise, that you concentrate on getting an effective design first before spending a great deal of time and energy studying and commenting on a system that is improperly designed for effective and efficient composting with a proper toilet fixture to negate the ability of filling the tank with non-compostable materials.
Clint