Evapotranspiration doesn't really happen in constructed wetlands unless it's warm and dry in my view.
I would suggest actually active ventilation in the chambers like we did in Carpathians which also removes the need for long pipes protruding into sky (I cant see them actually at your design). This really dries the pile no matter of the weather even when pouring rain. It doesn't really takes much energy -- 100 watts or so for all 4 chambers . If you have constant wind on the shore you might put a simple savonious rotor on the top to charge the batteries and run the fans. This will also provide lightning and music inside (esential part of our toilet).

Another thing I want to mention b is that I pour grease collected in the restaurant sink grease traps to the pile. This notably heats up the pile and decreases the volume. The pathogens probably don't enjoy the temperature too.

Hi All,

Thanks to everyone for the contributions on this discussion, I have learned a lot from all of them and I think the debate is really important and helps progress.
I have a couple of comments to make which come from my field of expertise which is plant biology:
I had conducted a year - long experiment growing a number of crops using fixed - dose fertigation of human urine from UDDT's. We had looked at both economical yield and short - medium term effects on soil biochemistry using biolog data etc.
Our results had shown that only certain plants, namely (my own term)ammoniophiles actually implement Nitrogen from fermented urine. This observation had been replicated by a number of other studies.
There are also issues with sodium toxicity(diet dependent) and Club-root in Crucifers.
Bottom line: you cant just disperse urine willy-nilly without testing the reaction of the crop/habitat first. It is also unfortunately Illegal in Ireland as we speak to leach the urine directly into the ground.

In light of that I think the urine diversion solution is certainly the right one in an ideal world, where a farmer will come with a stainless steel slurry tank and draw the urine to fertilise their fields sustainably, but in reality, this is not going to happen anytime soon.

I think the Issue with planning and designing a public facility is understanding capacity and patterns. In a North American national park, this is easy enough to do, as everyone comes and leaves the same way and probably pay to go in. On the wild Atlantic way, we have little or no Data
on Numbers, add to that the Irish weather which is bad at worst and unpredictable at best. this had lead me to a conclusion that the design needs to be: A. Modular, B. overengineered.
The modularity is expressed by the linear layout, the overengineering by using enormous tanks (7 cubic metres per unit) as well as the number of units which allows shutting down units that are over filling prematurely.
This Approach has been implemented by Clivus Multrum in the Bronx Zoo unit(1,000,000 visitors a year) and has been shown to be succesful.

When using Clivus - type containers, the question that remains is what to do with the leachate(namely urine with fecal solutes).
to that there are 2 solutions, bearing in mind the coastal dunes where it is likely to be situated:
1. Create a lined, organic based leaching beds using reed and other species, allowing full trans - evaporation without overflow, utilising the high wind speeds on the coast.
2. have a leachate sump which, when full, automatically re - pumps the leachate into the tanks, evenly distributed to reignite nitrification and mesophyllic decomposition.

the second option is more likely to be accepted by our engineers, however it is possible to have both as backup.
Volume management will consist of 1. Monitoring, 2. regulation by unit closures and 3. Addition of units.

I would appreciate contributor's thoughts of this and thanks again to everyone, especially Geoff!

Owner operating their own toilet is different from a federal employee operating a public toilet on federal land. The standard toilet for parks used to be pit toilets. They are very easy to create (dig a hole) and easy to maintain (no process). Pit toilets are not encouraged at this point. But if you are a park operator and previously you could dig a hole and put a toilet over it and call it good, you're not going to be excited operating a composting toilet: about having to haul up bulking agent, mix, shovel, and pick trash out of semi-raw waste, and then go and dig a hole afterward and transport the large volume of waste into the hole by hand. What's the difference between the pit and a compost toilet which stored the waste for a year before sticking it in a hole?

The difference is that operating a saw dust dry toilet is onerous for little biochemical effect. Pathogens are still there. Waste volume is bigger. Waste has trash in it. And while some probably dig it in a hole or scatter it around, most of them pack it out. Yosemite uses mule. Rocky Mountain uses lamas. One single toilet at Mt Rainer is packed out by one man with a couple buckets on his back and in his hands every week.

Composting toilets don't make much sense to me at high use public remote sites. If they actually made compost, great, screen the trash and spread it around the site. They don't. So why haul up the wood chips? I'm all about waterless toilets. I have one in my shop and sell a series of waterless toilets to public clients. I just don't claim they will make compost or make anything that they may want to put on their marigolds. First we need to prove a low cost and low hassle maintenance system at high use public sites. They if that is good, and mass is stabilized, figure out a way to post-sanitize (urea and ash is my preferred method) and then go for nutrient reuse.

Geoff

Actually many U.S. states permit the contents of dry toilets to be buried below varying amounts of soil. In the course of my research into existing state laws I discovered that in some cases it is state law (not federal) that governs what you can do or not do with this material. The minute you announce your intention to utilize said material as a "fertilizer" is the second that federal law takes over. See the following sections of two relevant wikipedia article that I researched and wrote for more info:

en.wikipedia.org/wiki/Urine-diverting_dry_toilet#Regulations

en.wikipedia.org/wiki/Composting_toilet#Regulations

It's crucial that those of us advocating on behalf of sustainable sanitation in the United States understand the rules and regulations (and when they don't apply) surrounding the management and use/disposal of the contents of dry ecological toilets.

Appalachians are a different matter. Toilets are maintained by volunteers. And they are more than happy with their mouldering toilets. I think these mouldering toilets work just fine and they are low enough use to not have ammonia inhibition issues. I have spent many days digging around and working inside an Appalachian toilet. Have you? I understand that the various National Park offices look the other way about the onsite disposal of the waste. The federal Title 40 Part 503 regs do not permit this disposal route into public parks, but I'd look the other way if volunteers were managing the poop.

I didn't sample toilets in Mexico. I will take your advice and use Canada and USA. Thank you for pushing me to be precise with use of my terminology. Lets be equally precise about our use of the term compost.

I found the viable helminth in a park in Canada, in a pile of waste that had been dumped on the surface, near a lake, but I try not to give out the names of specific sites / commercial systems during my PhD research.

There are regulations in USA and Canada and I think most public operators do wise to follow the regulations of their jurisdictions for the sake of public health and environmental health that they are in charge of protecting.

It is my experience (sampling dozens of public toilets) that when a public toilet shifts from low use to high use, it will suffer from ammonia inhibition and no reasonable amount of bulking agent can ameliorate these conditions. The addition of more bulking agent means more cost to get the bulking agent there, and more waste volume to move more frequently. It is then when urine diversion, with a robust mechanical system, becomes an excellent method to reduce waste volume, mass, and prevent solid waste from buildup of high ammonia levels so that local soil based invertebrates (like worms) can consume, semi-sanitize, and stabilize the waste.

Geoff

Seemingly lost in these generalizations about the routine failure of dry toilets in the park environment are the following success stories:

The Green Mountain Club (and, by extension, the Appalachian Mountain Club)* have apparently experienced great success over the last ~twenty years with their site-built "moldering toilet" technology. Users are requested to urinate in the forest and only use the toilets for defecating. In most instances that I am aware of the byproduct of these toilets is permitted to be buried sub-grade in the forest environment. When possible, red wriggler worms are utilized to enhance decomposition.

Also, for those unaware, the geographic region of North America includes Canada, The United States of America and Mexico. While the former two countries suffer relatively low rates of helminth infection the latter does exhibit unacceptably high rates. So, if Geoff sampled the byproducts from dry toilets located in parks in Mexico then it makes sense he found helminth ova. However, if he didn't travel at all to Mexico than he would do well to omit use of the term "North America" and instead write the names of the actual countries he worked in.

Speaking for the U.S.A., finding helminth ova in the byproduct of dry toilets located in U.S. parks could have something to do with the combination of that country's high rate of poverty and, in particular, childhood poverty, and the fact that access to the vast majority of parks (and thus toilets located therein) is free or low-cost. Low and limited income individuals and families (collectively, a group that suffers disproportionately from conditions like helminth infection ) are able to take advantage of the benefits provided by parks without having to break the bank in terms of cash outlay. For that reason, I'd estimate that public parks represent both one of the few saving graces in a country that otherwise marginalizes and disenfranchises people of limited financial means at every turn and an interesting but not necessarily representative sample source when it comes to analyzing pathogens in excreta.

++++++++

* Added by moderator (EvM):
See their manual in the SuSanA library:
Appalachian Trail Conservancy (2014). Backcountry Sanitation Manual, 2nd Edition. Appalachian Trail Conservancy, Green Mountain Club, USDA Forest Service, National Park Service, USA
www.susana.org/en/resources/library/details/2130

geoffbhill wrote:
I have found viable helminth ova in compost toilet waste in public composting toilets in North America. Needle in a haystack? Or are National Parks visited by people who travel all over the world and have a higher chance of carrying pathogens than the standard North American? Latter more likely in my opinion. Human feces are consumed by a wide variety of animals. If pathogens are still viable in the feces and other mammals or bird eat the feces, will they become carriers? Humans generally don't defecate in water bodies, but will these infected animals defecate in water bodies? These are unanswered questions in my mind.

Geoff, thanks for coming here, I really appreciate your work and as Elisabeth says I basically believe that non-working composting toilets are worse than no sanitation - because it might encourage reuse and spreading of pathogens by people who think that the material is actually safe.

But.. I basically don't agree with the above logic. Whatever pathogens are in human faeces, these exist in other wild species. I think it is very unlikely that the pathogens in human faeces would have any appreciable impact on the level of those pathogens in the wild. A very small amount of human faeces in a National Park would, in my opinion, be a tiny problem compared to other potential sources of the pathogens.

I'm prepared to be wrong if there are studies which indicate the impact of human derived pathogens on natural habitats in North America.

What is certainly true, in my opinion, is that such collections of untreated faeces could be a hazard to other humans using or managing the facilities.

In most scenarios this is unlikely to be a major problem because the pathogen rates are probably not high, because training and PPE is available and because good medical assistance is available in the USA. Therefore I think helicopter-ing (or other very expensive transporting) out from a remote site toilet waste is a total over-reaction. It is surely possible to destroy any possible pathogens in this kind of site by incineration if nothing else - without causing any significant impact to the surrounding environment.

I think human waste at our cherished parks and protected places should be minimized, should be managed in a system with low risk to staff/operators, and should not be disposed into these special places, but into approved systems for waste treatment offsite. Those are my views.

I think one has to consider the possible risks to the environment from the human faeces and compare them with the possible risks and impacts of using a helicopter (or other transportation system). As I recall, the amounts of faeces under discussion in each wilderness toilet are very small, therefore the risk to the environment is very small.

I haven't seen a single composting toilet produce compost. The name is a misnomer and has lead people astray for decades.

I totally agree. Faeces in a confined space with limited oxygen or carbon will not compost and therefore will not destroy pathogens. An utter fallacy.

Compost is a product of an engineered system with tight controls and a high level of scrutiny on the process and end-product testing which assures a very low level of risk and high level of assurance as a soil amendment. End-product from a public composting toilet is none of these. High metals and high pathogens.

Mmm. I'd be surprised if there were high metals unless a lot of other junk is being put into the sanitation system along with the human faeces and urine. But yes, I generally agree that many systems on paper appear to be only very imperfectly treat pathogens and only "compost" to a very limited extent. And as they're not usually monitored, the actual status is unknown - and therefore in my opinion can only be handled as if they contain high levels of potential pathogens.

But, again, I'm not sure that we can be so definitive when we're talking about a system as Bogdan Popov has described in Ukraine and others have recently described on this forum. We're simply not talking about the "composting toilet" that infamous enthusiasts like to pretend is easily managed with a bucket and a bit of sawdust. It seems to me that a lot of effort is being done to introduce engineering to aerate the faeces, and with sufficient carbon it seems to me that it is entirely possible that this will, in fact, compost.

This may indeed reduce the risks to the extent that with proper supervision and availability of PPE and healthcare, it is an acceptable way to safely dispose of the faeces. What I do agree with, again, is that it is not possible to tell the actual pathogen loading the material by visually observing it and therefore the risk assessment may be quite wrong. But it is hard to imagine, in this scenario, that the risk with this kind of system is worse than a basic pit latrine.

If we want to recycle nutrients from human waste, it makes much more sense to recycle urine which has the majority of nitrogen and phosphorus in human waste, few pathogens, and no heavy metals. Urine flows by gravity and self sanitizes.

As we've heard recently, this idea is disputed. Several academics have told me that urine should not be considered to be sanitised or pathogen free and that there are risks in using it even after urine-diversion. And I also suggest that the balance of plant nutrients in urine may not be appropriate for particular plants or particular soils anyway. There may in fact be some benefits from true "composting" compared to using fresh or stored urine in terms of reuse.

Fecal matter has organic matter, energy, pathogens, and heavy metals. I think it has value only in places with little to no organic matter in the soils and a lack of other low-pathogen organic waste streams (such as food waste or ag waste).

Geoff

I don't accept this. Composting changes the availability of nutrients in the urine and faeces and therefore may produce something which is more appropriate for a given crop or soil than simply using urine.

Of course it totally depends on exactly what is being used and where and for what purpose.

Yes as Geoff has pointed out the misuse of the term "composting toilet" has not helped the development and upscaling of ecotoilets. The stale urine odour from systems that do not compost will sooner or later turn people off. About a year ago I recorded a testimony to the Vermont Legislature just on this question:



Clivus multrum is however set up to produce sweet smelling compost and an odourless liquid product which is mainly nitrate. This has been a very successful development especially for public toilets since urine doesn't need to be diverted and maintenance can be kept minimal. I would venture to say this sort of system is ideal for the "pristine" parks of North America. Food wastes can also be added. And the final compost can be heated or even incinerated on site under controlled conditions for onsite reuse or disposal.

But let's get back to Ireland. Ron, I think the drawings look great. The shelter from the rain is important for both users and those emptying the system and this will make them popular. The run-off product from the Clivus compost heap can be fed into a mini-wetland populated by some hardy higher aquatic plants. Greywater would feed into the same unit. Solar driven lighting and ventilation, excellent.

Urine diverting systems can also be tried but these will require daily maintenance.

Humans are top chain consumers and we ingest heavy metals in our food. Some pass through feces and some stay in our body.

In western world there are low risk organic wastes that are lower risk to compost and use as soil amendment. Such as food waste, yard waste, and paper waste. The latter doesn't have many nutrient per mass.

Lets shift the conversation. People are connected with the idea of recycling their fecal matter to feel good about being a human on the planet. I get that and agree in principle. Practically speaking, there are rational choices and emotional choices. I have a waterless urine diverting vermicomposting toilet in my office. I use it every day. One day I'll start collecting urine for my garden. Maybe 10 years from now I'll have to figure out what to do with the fecal matter thats been sitting on the ground being eaten by bugs. The practical thing to do would be to dump it in my green bin for composting and full pathogen reduction. Composting plant is local and the bin gets collected every week regardless of whether this load is in it or not. The emotional thing would be to go to the effort of digging it under the ground and planting a tree on top. The digging part sounds like a lot of work.

Geoff

www.ecodomeo.fr

A Urine diversion seat which is perfect for public use as all liquid and solid are separated without requiring behavior change. System is robust to clogging and even has an over flow in case the lower pipe gets clogged.

Hi Elisabeth!

Yes we have a care taker emplyed full-time when the toilet is operating. I cannot imagine it would work without a care taker.

I think the doctor was talking about Enterobius ones . Small white things. Our children once had them and he just explained the ways people get them meaning they are quite easy to catch. Intresting note also I remeber -- people consuming lot's of shugar and bread-like products are more prone to helmintic infestation while people who regularly eat garlic and (!!!) highly fermented traditional sheep cheese found in Carpathians (bryndza) develop kind of immunity. It was a talk about the importance of traditional diets since mountain agriculture was all about animals and people there should be more infested with helmints while actually they were not.

Hi Bogdan,

Could you please remind us about the care taker system that you have for your toilet? There is a care taker there the entire time that the toilet is open, right?

I can't imagine that helminth eggs are "everywhere" in the Ukraine. This would mean that lots and lots of people have intestinal worms?? Perhaps your doctor friend was referring to pathogens in general, like bacteria.

Geoff, are you really that worried about heavy metals in human feces or in the material from composting toilets? I thought it was mainly the pathogens that you are worried about? Indeed, why would there be much heavy metals in human feces? Yes, heavy metals are in sewage sludge and that's a problem, but in feces from composting toilets I wouldn't expect so?

Referring to this paragraph in your post:

If we want to recycle nutrients from human waste, it makes much more sense to recycle urine which has the majority of nitrogen and phosphorus in human waste, few pathogens, and no heavy metals. Urine flows by gravity and self sanitizes. Fecal matter has organic matter, energy, pathogens, and heavy metals. I think it has value only in places with little to no organic matter in the soils and a lack of other low-pathogen organic waste streams (such as food waste or ag waste).

Cheers,
Elisabeth