Dear colleagues

First of all, thanks to Elisabeth for bringing this thread to my attention and for inviting me to share the thought-processes that went into the “dry toilet” definition used by the Compendium .

I find it interesting (and a bit worrying actually) to see the different definitions and confusions that still prevail, like:

So if I understood you correctly you would prefer to see the term "non-flushing toilet" used and then below that category would be dry toilet (UDD, composting) versus pit latrine toilet. Correct?

or

I disagree that a compost toilet is a ‘dry toilet’ because composting only works with water, even vermi-composting requires a certain moisture level for the worms to survive as far as I know.

This mainly has to do with what one implicitly includes or excludes when talking about this term.

One of the main original purposes of the Compendium actually was to bring some order and clarity to the confusing and conflicting use of terms. It aimed to try and streamline sector terminology, so that experts can better understand each other when talking about the complex issue of sanitation.


Dry toilet:

As already cited by Elisabeth, the definition used in the Compendium is (P. 44):

A dry toilet is a toilet that operates without flushwater. The dry toilet may be a raised pedestal on which the user can sit, or a squat pan over which the user squats. In both cases, excreta (both urine and faeces) fall through a drop hole. In this compendium, a dry toilet refers specifically to the device over which the user sits or squats. In other literature, a dry toilet may refer to a variety of technologies, or combinations of technologies (especially pits).

The Compendium also says (P. 42):

There are two main types of interfaces: dry technologies that operate without water (U.1-U.3) and water-based technologies that need a regular supply of water to properly function (U.4-U.6). Different User Interface technologies generate different output products. This influences the subsequent type of Collection and Storage/Treatment or Conveyance technology.
In any given context, the technology choice generally depends on the following factors:
• Availability of water for flushing
• Habits and preferences of the users (sitting or squatting, washing or wiping)
• Special needs of user groups
• Local availability of materials
• Compatibility with the subsequent Collection and Storage/Treatment or Conveyance technology

Why this definition? The Compendium distinguishes user interface, collection/storage and conveyance as “functional groups” of technologies, and highlights what can be combined or not. That is the main idea behind.

A toilet is a “user interface”, where the user has to “go”. The user does not usually care if that is connected to a single pit or VIP, composting chamber or dehydration vault, septic tank or sewer (although the experience and operational requirements might be influenced by those, because the technologies are of course interlinked with each other). The latter are all “collection and storage” or “conveyance” technologies”, to which a toilet can be linked. They are not part of the toilet as such, but part of the sanitation system.

A dry toilet can connect to a single pit, single VIP, double VIP, Fossa Alterna or composting chamber. All of these collection options are compatible with the dry toilet, and possibly also with a special type of dry toilet, the urine-diverting dry toilet . As mentioned in previous posts, the moisture content required or typically present in these collection and storage options differs, but this has nothing to do with the dry toilet itself. That’s why it is so important to keep the two functional groups apart.

Keeping them separate helps to be clear what one is talking about, and to systematically design a system that is optimal for the local context. Different stakeholders are involved in dealing with different functional groups. When designing a system, asking separate questions about the two (while considering how both influence each other) will help to come up with the optimal technology combination:

• User Interface: Who will use it? Washers or wipers? Squatters or sitters? Is water available for flushing? Are there any special needs? How will it be kept clean? Cost, who will pay, etc.
• Collection and Storage/Treatment or Conveyance and the rest of the system: Is there a desired end-product? How to treat it to the requirements? How to transport it? Who will empty/transport it? How? How frequently? What are the groundwater and soil conditions? Cost, who will pay, etc.

From this perspective:

• striking dry toilet from the vocabulary is clearly not possible
• a pit latrine is more than a dry toilet – it is the combination of a dry toilet with a pit
• dry toilet does not say whether faeces stay dry or not, or how dry or moist it will be in processing
• it is not correct to say: “It is common that the term "dry toilet" or "dry sanitation" is used to refer specifically to a urine-diverting dry toilet or a composting toilet.”
• it is also not correct to say: “Pit latrines without a water seal also fall under the category "dry toilet".”

Dry Sanitation:

@Elisabeth: what leads you to the conclusion that

When people speak of "dry sanitation" they usually mean sanitation systems with dry toilets with urine diversion, in particular the urine-diverting dry toilet (UDDT).?

In your experience, is the term “dry sanitation” even used much at all?

I agree that dry sanitation is not a good term because sanitation always has to account for more or less significant liquid streams. And a definition of dry sanitation where a water flush can be used is rather confusing.

Perhaps that’s the reason why there is no proper definition (we also did not define it in the Compendium), and why the term is not that commonly used by sector experts (at least in my experience).

I see no real need to define and use the term dry sanitation, so scrapping it from the vocabulary would be good. "Non-sewered sanitation" is definitely a much better and much more useful equivalent.

“Dry excreta management” would also not be clear. What happens to the liquid part of excreta (and perhaps flushwater)? Is FSM dry excreta management? Let's rather directly go for more concise terms like dehydration, infiltration, composting, or evaporation, ...

With kind regards,

Lukas

Hi Diane,

No problem!

I'm away for the next week, but I'll add it as a Wikipedia assignment for myself to make sure it gets some attention.

Hopefully the Wikipedia WASH scene will look great by World Toilet day!

These are important and much-needed differentiations, Stuart. Elisabeth made some improvements to "dry toilet" and "dry sanitation," based on your inputs. We need to back up even further and work on the "toilet" article. Your language and clarifications would make that article much better. It's likely to get a lot of hits come World Toilet Day.

I started working on just "readability" for the lead and felt it would not be a good use of time until the article itself gets some attention. I know you're working on a few other topics, but could you add "toilets" to your list? Given how much you've thought about these distinctions, I think you could make quick work of improving the definitions.

Diane

That's a good suggestion in my opinion... I agree with you about striking "dry sanitation" and "dry toilet" from our vocabulary. What do others think? It would only work if we reached a consensus on this.

One method that can help to cement a consensus that we have reached is to get the Wikipedia articles about dry toilet and dry sanitation right. Here I have the problem that I need to cite a reliable source for any statement that I make.
E.g. if I write: "In the WASH sector, the term "dry toilet" is used differently by different people. It is common that the term "dry toilet" or "dry sanitation" is used to refer specifically to a urine-diverting dry toilet or a composting toilet." - then what reference could I cite? A discussion here on the forum doesn't count. Someone would first have to publish a paper of sorts on this topic and then I could cite that. A website of a reputable organisation, like UNICEF, UN Habitat and alike would also count.

By the way, a somewhat related term that I see used more often these days, e.g. in grants by the Gates Foundation, is Non-sewer sanitation (NSS). E.g. in this grant:
"Leadership capacity development on non sewered sanitation and FSM"
www.susana.org/en/knowledge-hub/projects/database/details/485

I guess it's meant to replace "dry sanitation" but could relate to any type of toilet; it just means the excreta is not transported over longer distances in sewers.

Regards,
Elisabeth

Hi all,

I agree that ‘dry sanitation’ does not make much sense and should probably be scrapped from our vocabulary.

I also agree that ‘toilets without flush’ can be a ‘main group’ with ‘subgroups’ of 1) de-hydrating toilets (dry excreta management), 2) composting toilets, and 3) pit latrines, ... what else?.

Because Dean indicated that there can be de-hydrating toilets without UD, subgroup 1) may include UD and non-UD.

I disagree that a compost toilet is a ‘dry toilet’ because composting only works with water (home.howstuffworks.com/composting1.htm ) even vermi-composting requires a certain moisture level for the worms to survive as far as I know.

… and suddenly I notice that we can also do away with the ‘misleading’ ‘dry toilet’. We can still use it for ‘de-hydrating toilets’ or for ‘dry excreta management’ but since we do not need 3 names for the same thing, let’s stick to ‘de-hydrating toilets’ and forget ‘dry toilets’ as well as ‘dry sanitation’.

Ciao
Hajo

Yes Elisabeth that would make sense to me, as my particular interest is in the use or not, of water as a disposal method, and the re-use ideas that are out there.

Cheers
Ross

Dear Ross,

So if I understood you correctly you would prefer to see the term "non-flushing toilet" used and then below that category would be dry toilet (UDD, composting) versus pit latrine toilet. Correct?

Dear Stuart,

Thanks for your detailed post, very interesting and very good that you pointed out the differentiation between dry toilet and dry sanitation.
The paper that you mentioned has this URL, by the way:
jrtph.jcu.edu.au/vol/v01scott2.pdf

Your point really convinced me so I quickly made a change on Wikipedia: Before, the term "dry sanitation" redirected to "dry toilet". Now I have made the redirect to here:
en.wikipedia.org/wiki/Sanitation#Dry_sanitation

There it says:

Dry sanitation[edit | edit source]
Further information: Dry toilet

The term "dry sanitation" is somewhat misleading as sanitation includes hand-washing and can never be "dry". A more precise term would be "dry excreta management". When people speak of "dry sanitation" they usually mean sanitation systems with dry toilets with urine diversion, in particular the urine-diverting dry toilet (UDDT).[13]

This is actually something that I wrote about 2 years ago... Might be time to improve and expand on that. Suggestions?

I have always had a problem with the term "dry sanitation". In my opinion it is a complete misnomer. Why? Because sanitation is more than just excreta management. Sanitation is also greywater management, solid waste management and drainage. It also includes hygiene. Now can anyone imagine hygiene and greywater management without water? No. So "Dry sanitation" makes no sense and it should rather by called "Dry excreta management".

What do others think about that?

I think it is important to get our terminology right in the WASH sector because otherwise it all adds to the confusion that the general public has about sanitation. If we all agreed on the right terms, I think this would go a long way in improving understanding of all the issues.

Regards,
Elisabeth

Hi Elisabeth,

My thoughts are as follows with the disclaimer that the terminology I use is native to South Africa. The brief version of the point I'd like to add is that a dry toilet and dry sanitation mean two very different things to me and my terminology.

"Dry sanitation" and "dry toilets" are not the same thing in my understanding and terminology, and therefore the definitions of each are different and not interchangeable. To me a toilet is the pedestal you sit on or squat over, whereas sanitation may refer to the model of pedestal+treatment solution, or pedestal+FSM chain, etc.

"Dry sanitation" to me is non-waterborne sanitation. Flush toilets part of a waterborne sewered network would not be "dry sanitation". VIPs are "dry sanitation", as no water is added to the toilet in a flushing manner or for transporting reasons.
Reference: "Dry sanitation is defined as the disposal of human waste without the use of water as a carrier", Scott, E. 2002, Dry Sanitation Solutions, Journal of Rural and Remote Environmental Health, 1(2), 23-25. This reference is useful for this definition, but it doesn't unpack the definition further.

A "dry toilet" definition is where it becomes a lot harder to define: A toilet can still be part of a "dry sanitation" model, but the toilet itself is not necessary a dry-operation pedestal. Pour-flush or low-flush toilets are "dry sanitation" in my mind, as despite them using water to flush the pedestal, as water is not used to transport the faecal matter offsite. The flush merely acts to create a water layer between the user and the pit where the feacal matter degrades, for hygienic and aesthetic reasons. Thus, I can imagine that a debate about "dry toilets" would have to look at system boundaries, on whether a pit is part of the boundary, since VIPs don't use water, but the pits themselves can be extremely wet (and sometimes almost entirely liquid). A dry toilet to me, is a pedestal where an effort is made in the design/concept to ensure that faecal matter remains as dry as possible, and perhaps even takes immediate dewatering efforts on/by the pedestal.

"Dry toilet" = A pedestal where water is not used to flush the pedestal, and inherent design efforts are made to dewater the faecal matter. E.g. UDDT, Composting toilet (e.g. EarthAuger).
"Dry Sanitation" = A sanitation model where water is not used to transport faecal matter off-site.
Note: A pour flush or VIP can be part of a "dry sanitation" model, but not a "dry toilet".

To me as a manufacturer of "Waterless or Composting Toilets" I could not describe a pit toilet as a dry toilet. Any sanitation that allows urine and solids to mix along with any other material deposited can hardly be "dry". These titles are not specific and nor should they be when considering that the application of non - flushing toilets is varied according to the situations in which they are applied.
Toilets are either flushing or non-flushing, and beneath that broad heading there are many sub categories. I supply pedestals and systems to all manner of sanitation applications, including over "pit" toilets, and I would not like the tag of pit toilet applied to my products.

Thanks for your responses so far! Please keep them coming as I find it very interesting. It shows that - as I suspected - many of us mean different things when we say "dry toilet".

It seems that the definition that the people behind the Eawag-Sandec Compendium chose might not (yet?) be universally accepted amongst people in the sector.

They had a very simple definition. See here: ecompendium.sswm.info/sanitation-technol...-toilet?group_code=u

A dry toilet is a toilet that operates without flushwater. The dry toilet may be a raised pedestal on which the user can sit, or a squat pan over which the user squats. In both cases, excreta (both urine and faeces) fall through a drop hole.

Here, a dry toilet refers specifically to the device over which the user sits or squats. In other literature, a dry toilet may refer to a variety of technologies, or combinations of technologies (especially pits).

I wonder if anyone who worked on the compendium could tell us in this thread about the thought processes that went into this definition? Would there be any room for modifying it? Or do people have to get used to the idea that a simple pit latrine classifies as a dry toilet even if it goes against our gut feeling (as the pit is not dry at all)?

Meanwhile, Hajo's point was very valid, I think:

Therefore, if someone uses the term 'dry toilet' or 'dry sanitation' it should always come at first use with a short explanation whether it is a system without any flush or a system with a dry faeces containment avoiding any misunderstanding.

Greetings,
Elisabeth

What about dry toilets that do not divert the urine but dehydrate the contents?

Dry toilets means a toilet that operates without water and has a divider so that the user, with little effort can divert the urine away from the faeces.