You state that all UDDTs need some moisture. That is the opposite of my experience. I do everything I can to stop any moisture from entering. My goal is for the fecal matter to dehydrate and heat to a temperature that will ensure that all pathogens and helminthes are killed. Within 6 months I want a dry odorless product that can be used as a soil conditioner. This along with the nutrients in the urine can give the local farmers a higher crop output. The soil will also be healthier and hold more micro nutrients and moisture. ie the soil will be healthier.
It must be simple. Parts break, electricity goes out, pumps malfunction, and additives get used up.

Couldn't agree more Tore. It always surprises me when pour flush is nominated,as there is no getting away from the transport risk of pathogens traveling with any water passing through the pile. All UDDT,s need some moisture and this is adequately handled by light cleaning procedures, avoiding inundation.
More attention should be paid to what areas qualify for simple sanitation so that large schemes have a chance to be successful in the long term, and this should include the ground types, rainfall, flood risk, reuse possibilities, and cultural awareness.

I would be a big proponent of the UDDT for several reasons.
1. One of the biggest polluters of the ground water is fecal contamination. A properly maintained UDDT will ensure complete separation of the fecal matter from the drinking water.
2. Is there no agriculture. The urine is one of the best fertilizers and will result in greatly enhanced crop production. The treated fecal matter makes great soil conditioner.
3. In a flush toilet where does the water/fecal matter go? If in a septic tank it will need to be pumped which seldom happens and the ground becomes contaminated. In worst case basis raw sewage bubbles on the ground and insects/vermin transmit the pathogens.
4. A twin UDDT will allow the fecal matter to sit and heat for 6 months allowing pathogen die off and safe use of the fecal matter. It is also dry and has no odor so it is easier to convince locals to service and use the "human fertilizer" product.
5 In a flush type system that has a a central treatment facility is the fecal matter being properly treated. The effluent pipe oftens ends in the ocean or a gully somewhere so the pathogens get into the environment.
6. The system needs to be simple, safe, and acceptable to the population to service.
7. Whatever system is used the population must be willing to service and maintain. Keep it simple and use minimal moving parts.

Hajo

A good response which shows the sometime imbalance between the Westernised theory put into fact and the localised perception...but in general discussion, there seem to be a few choice quotes popping up from Freud and Einstein and Mr B Fuller and Einstein again, which, frankly, come across as rather in-joke patronising and ho-ho-ho too clever by half.

As a designer and manufacturer of aid products I know that simplicity of result in terms of freightability, robustness, usability, affordance of dignity etc is a hard won objective - harder by far than designing in the hedonistic holistic hashtag world, and doing it doesn't afford me the right to pontificate about the task at hand. But I am entitled to comment...

Referring to H's comments about local expectation of higher level Western systems, I think he has a point that permeates right across to camps and countryside as well as peri-urbanism. We make use of certain techno materials that I have 'discovered' from working in the Western design world, such as polypropylene 3d core panelling, for latrine structures. I believe, and some field officers have confirmed this - that such stuff gives the products a certain direct 'impact' factor, much as H describes - this results in attraction to using them properly far more so than would happen with a local resourced material. And also generates the oft-ignored 'sense' that whoever provided these pieces must care about and are ready to share these other-world goods with the recipients' for their dignity and well-being.

hi Clint,

I fully agree that we should strive to save resources and also recycle water. But the sample you present (your picture and the associated text in an earlier posting by you, I attach here again) seems to me too complex for the African market, if to be applied at large scale and for the masses.

I don't know what the situation in Costa Rica is like and who your customers are, but in the majority of peri-urban households in Africa your system would probably not last a year. We need simple sanitation systems, preferably without power supply, without pumps, definitely without electronics.

remember: Everything should be made as simple as possible, but not simpler.
Albert Einstein

The comparison between cell phones and toilets does not really fit. The costs of a phone are about 1/10 in investment (for the user) and if he cannot pay for air time, he is off-line (mostly) without major consequences, while the lack of emptying his toilet always stinks like hell...

ciao
Hajo

Hola Amigos,

Almost as essential; The technological communication infrastructure of the recent past was by foot with a runner transporting and sharing the information throughout Nations via the villages and communities.

While the academics, regulators and the Runner's communication professional's union searched for runners with longer legs and shoes for more speed in getting the information transported faster, private enterprise came technologically forward with the decentralized/personal cell phone, which elevated humanity in boundless directions while creating opportunities beyond comprehension at that time.

Even in the remote villages persons have elevated their level of communication existence by utilizing cell phone technology.

As Hajo's message also expounds, "Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction".
E.F. Schumacher.

Proven, affordable, beyond-sustainable, attainable, simplistic, decentralized, locally manufactured/installed/monitored/maintained profit-oriented, private water capture, supply and wastewater treatment and recycling technologies exist.

But, the majority of institutionalized/standardized humanity lacks the education, knowledge, understanding and comprehension that ALL human toilet deposits can be safely converted and made re-usable as soon as possible (as in immediately), onsite utilizing in-vessel source separation and aerobic/composting/vermiculture treatment technologies.

R. Buckminister Fuller described our planet as "Spaceship Earth", with a cargo of RESOURCES! ALL human and organic WASTES are actually RESOURCES and we HAVE the technologies to treat them accordingly, professionally, environmentally and economically.

It is time to get out of the pits and "Think" like Einstein!

El Hombe de La Lluvia

dear Kevin,

but please, while looking 'what might be done in the short term to improve existing systems' don't forget to 'look at ways of introducing radically improved systems'.... which may take years and require a lot of patience and effort...

And don't forget Albert Einstein: 'We can't solve problems by using the same kind of thinking we used when we created them'.

ciao
Hajo

In reply to Dean and Hajo

Yes - groundwater pollution is possible but as I already said, that is true of most on-site systems. The important thing in Indonesia is that people are aware of the problem and do not use shallow groundwater for drinking. The links between leachate and pollution of deeper groundwater needs further research. Also, the available evidence suggests that percolation paths do eventually get at least partially blocked but it can take years - when I started to investigate the situation, I thought that blocked percolation paths would be a much bigger problem than they apparently are.

I don't think that the tanker operators are 'cheating' the people that they serve - I said that it is possible that some sludge may remain in tanks but there is limited information on this. The key point is that the on-site systems typically go for years before they need desludging. There are efforts in both Indonesia and the Philippines to introduce scheduled emptying but this requires a high degree of government organisation, which in most cases is still not there. One example is Dumaguete in the Philippines, where scheduled emptying was introduced but is no longer functioning as such, although people pay a regular amount to have their pit emptied and can call on the service as and when required. in Indonesia, the only service is often that provided by the Government - the lack of private sector services suggests lack of demand, a point that is reinforced by discussions with private sector operators in some towns.

The system is not ideal but it satisfies people's needs. It is all very well saying Government should do this and people should do that but I go back to my point, what to do when the basic conditions to support more sophisticated and better services do not exist. Yes Hajo, it is important to develop capacities but how long will this take, given the low political priority that sanitation has in most countries. The present system could be described as a 'second-best' solution in that it has flaws but there are no short-term alternatives. It is worthwhile to look at alternatives such as worm-based options, presumably like the system that Oxfam has trialed in some places, but these are going to take years to mainstream and there may be issues with them. Time will tell and I think the key issue will be whether users are willing to commit to the work required to maintain and operate such systems.

I have spent the last four or five years looking at septage treatment. Indonesia probably has more septage treatment plants than any other country and there are big issues - they are built but underutilized, mainly I think because of lack of demand, and poorly operated and maintained. Despite this, surface water pollution is not as bad in Indonesia as in the countries of South Asia, where many people connect toilets directly or via crude interceptor tanks to the drainage system.

By all means look for improved alternatives, but be aware of issues of scale and do not completely dismiss what people do themselves. In the case of Indonesia, some people build a two compartment pit, the first sealed like the first compartment of a septic tank and the second with percolation from the bottom of the pit - it would seem worthwhile to promote this improvement with local builders, who construct most of the tanks.

To summarise - by all means look at ways of introducing radically improved systems but not at the price of completely ignoring what might be done in the short term to improve existing systems.

Kevin

hi Kevin,

I want to question your judgement that 'overall the system works reasonably well and puts relatively small demands on government services, which is a plus when those services are not strong'.

I would not call a system working well when

• the leachpit leaches contamination into the ground water;
• the leachpit does not leach because solids clog the pit floor;
• the vacuum truck operator 'cheats' the customer by only pumping the fluids on top of the solids.

To stop all this, the governance and supervising capacities of respective authorities have to be developed. After all, that is what they are there for: to ensure sustainable services to the public.

ciao
Hajo

Hi Kevin,

hmmm, yes... but what happens to the vacuumed sludge? Central treatment plant?

Seems to me that:

Wet areas have wet sludge in the pit that will contaminate water.

Dry areas have dry sludge in the pit that is difficult to remove.

No doubt sludge is responsible for reduced percolation.

If the solids were intercepted in a basket and digested by worms, with only the liquid percolating into the leach zone (soil), "sludge" would be a thing of the past.

cheers
Dean

Good point about the leachpit. I have had a quick look at the results of a survey that was done in several towns in Indonesia. Certainly, both sludge and supernatant water were present where the water table was high. Just under 60% of pits in areas with low water table had water above the sludge. The Indonesian pits only allow percolation from the base and this may reduce the rate of percolation.

The results showed that the average time to the first emptying of the pits was something of the order of 15 years - I would have to look up the exact figures. After that, repeat emptying was often required after another 2-3 years and this does suggest to me that the need to empty came about because the percolation mechanism was failing rather than because the pit had filled with sludge. That is speculation and is not definite but it fits the observed facts. Whatever the exact mechanisms, it does seem that the sludge accumulation rate is low - less than 20 litres per person per year on average - and this has implications for sanitation design. The available figures for Africa are quite variable but I do think that this reflects the much greater risk of bulky materials being dropped into direct drop toilets.

The other point from the Indonesian experience is that vacuum truck operators did not report problems with emptying pits, although it is possible, perhaps probable, that they were not removing the more consolidated material at the bottom of the pit. However, overall the system works reasonably well and puts relatively small demands on government services, which is a plus when those services are not strong.

Kevin

Dear Kevin and all,

if 'the content of these leachpits is fairly fluid and can be removed by vacuum tankers' then I would say, it is not working as a leachpit. Probably due to high ground water level or because the soil is not permeable or has been clogged by solids in the effluent. But I fully agree with you that situations in each country and even in each town have to be analysed individually to find do-able solutions.

Regarding institutional arrangements, I do not expect them to be there and ideal. I am saying that with the development of technical sanitation plans (infrastructure and service chain), also the capacities of public and private stakeholders have to be build to provide and manage these service chains.

This is possibly one aspect forgotten in the past: sanitation development is not only building toilets but also building service chains and the capacities of potential service providers as well as the strength of sanitation governance. A task for at least 10 years... in one town...

ciao
Hajo