Dear Paul,

Generally, odors are emitted by concentrated urine. If people have large fluids intake, the dilute urine produced, will emit less or no odors. Keeping the urinals area well-ventilated (in some cases, mechanical ventilation) will help in reducing odors. Likewise, plently of sunshine also helps in minimizing the odor problems. Since you are going to reinvent the toilet, try cascading the flow of urine in urinals. Cascading urine provides aeration, which in turn, will reduce odors.

I have, however, one question: what is the application of waterless urinals in Muslim countries, where we must use water, while using urinals.

Good luck

F H Mughal
Karachi, Pakistan

Hi,
maybe it goes to another tread but marijn wrote:

fit urinals with a device (be it a condom

we tried that out. At least peruvian condomos were too sticky. they glued together. Who has tried them out as well?
But our experience is...over 400 simple waterless urinals (fiberglass)... you just have to care that the urine flows down, no point at all where it could accumulate. No 90° bending (VERY IMPORTANT, as easily at that point you have "ponding"), strong slope, the proper urine piping is crucial. We had some problems with odour, but ALL related to the menitoned errors.

So our experience is: it is not necessary to have smell stops in cases of individual toilets or a small number of toilets.

Regards Christoph

Dear Paul,

Some nasal field observations.

A well built and operated UDDT is indeed remarkably smell free, you kind of have to smell it to believe it.
Also, yes smell, or the absence there, off for me is important in how much I enjoy using a toilet. I think this would go for most people, and though people can put up with a lot, it is very important to built toilets that can be kept clean easily. Partly for user acceptance, but also because people in general try to keep a clean place clean and get careless if the place is dirty already.

It is indeed possible to fit urinals with a device (be it a condom or one of those South African blue silicon valves) to eliminate the odor from the storage tank. Further, I think that a lot of the ammonia smell that can be observed in urinals and squat toilet (especially those used by men)is from urine that misses the mark and dries up next to the toilet into the concrete.

I would not put the smell of a unventilated pit latrine over a smelly set of urinals, but each to their own .

Marijn

Thank you to all of your for your comments,

Julius, my initial research has certainly implied that bad odour is often related to miss-use. It is good to hear you reiterate this point and it is interesting what you have said about user acceptance.

Julian it sounds like you have had some good experiences in this area, it's very interesting that you would prefer the mixed odour of a pit latrine over a poorly maintained dry urinal. It sounds like the Canadian dry urinal you described may have utilised a cartridge similar to that described by Florian in his first point.

And thank you Florian for your useful tips on helping to limit odour on waterless urinals.

Thanks again to all of you,

Paul

Hi,

I think odor is a serious issue that will in many cases greatly affect the acceptance of a system, thus it pays to invest some thoughts on how to control odors.

For controling oders from waterless urinals, I think there are three things to think about:

- a good odor seal at the urinal: there are different options, but the "condom" type is the most simple and efficient I know
- pipes should have enough slope to elimiante stagnating urine
- urine piping should be ventilated (as it is often recommended to keep urine tanks unventilated to minimze nitrogen losses, a siphon or similar seal may be needed between the piping and the tank)

Florian

Interesting research topic, Paul!

I used to regularly use a dry urinal at the city government office that I worked at in the Philippines, where the pipe from the normal ceramic urinal ran downstairs to a jug that held the urine (which was then applied to the government fruit trees somewhere, or so they said). I also used to use a much higher-tech dry urinal at my old university in Canada.

In the latter case, of course, odour was a minimal issue, because of the fancy cartridges that I can only assume the advanced dry urinals make use of. However, I - a sanitation guy - was always quite grossed out by using the dry urinals in this Philippine government office, as the smell that wafted up from them was quite overpowering. I'd honestly prefer the mixed smell of a pit toilet (even if not a VIP) compared to the stench that this open urine jug emitted! So, yes, I - as a user - was definitely put off by these urinals, and no efforts were made to contain the odour in any way. How could you, really, on a standard urinal anyways? Some sort of pedal latch or something would be needed to be able to close the pipe when not in use and prevent the odour from leaking out.

This really is the only solution I've seen in dry toilet environments (or pit toilets, for that matter) - a makeshift lid over top of the hole. It does the job for the most part, and keeps the rodents and insects out too, but obviously isn't the most aesthetically pleasing solution and perhaps adds a sense of inferiority to the toilet.

A 'reinvented' toilet - if you could design one - would surely be able to contain these odours without a makeshift lid! Good luck!

Cheers,

In UDDT latrines bad odor seems to be mainly related to miss-use, insufficient dry matter addition or plain too humid conditions that all result in an moist and odorous feces compartment. Besides smelling, this often leads to breeding of flies and maggots that are an even bigger issue that odors.

Users used to standard pit or badly build VIP latrines are used to toilets being smelly and will not outright reject a toilet that is not close by their houses only due to smell. However that doesn't mean non-functioning UDDT (as explained above) can be seen as acceptable.

Hi All,

My name is Paul Mackereth and I am working with Loughborough University as part of the project team being led by Professor M. Sohail to Re-invent the Toilet towards the Gates Foundation Challenge (see here on the forum: forum.susana.org/forum/categories/105-pr...orough-university-uk).

I am hoping to use this thread to start a discussion about a variety of users and their perceptions and experiences of toilet related odour. I understand this is a very broad topic but if any one has any interesting experiences about how odours have changed the behaviour of users please share below.

I am also interested in the types of 'work around' solutions the users implement to avoid bad odours. For example innovations such as the VIP latrines but on a smaller scale.

To start the discussion does any one have any experiences regarding dry urinals? Is odour an important issue where the flush is absent and if so how do the users combat this?

If anyone would like to contact me directly let me know and I will send my email address.

Many thanks,

Paul Mackereth