Composting Toilet

NickB

Full Member
Does anyone else on the forum have a composting toilet in their van?
I made my own dry (urine separate) one a few months ago and gave it (not literally) it's trial run over the last weekend in Malvern.
Worked fine!
*IF* anyone is interested I'm using Irish peat moss,with an Armitage Shanks Bakasan open front (horseshoe shaped) seat.
 

Squiffy

Full Member
Morning Nick, I'm not hi-jacking your thread, but I must admit to being confused with "Urine seperate" so I googled this article and thought it might be of interest to others reading your thread. 🙂

In many applications the choice is between the two types of composting toilet; a urine separating compost toilet (Separett, Wostman, Biolan Separating Dry) or an internal composting toilet (all Sun Mar, other Biolans). Both types are self vented so odour is not an issue with either. But there a subtle differences between the two. Here, I try to explain the pros and cons of each type so that you can make an informed decision.

Operation

Urine diverting toilets work by separating urine and solids at source. All use of this type of toilet must be seated. Urine is collected at the front and piped through the toilet to the outlet. The solids fall into a container at the back of toilet. It is important to note that a urine diverting toilet does not break down the solid waste into compost. It merely collects so it can be removed and composted outside. Urine is piped to a container or a soakaway outside as it does not present an environmental threat in most circumstances. Neat urine, from most people, is relatively sterile. Internal composting toilets do not separate urine from the solids. The moisture and Nitrogen from the urine are required to fuel the composting process in the unit. In an internal composting toilet bacteria break down the waste in the toilet, and in so doing, generate enough heat (up to 70 degrees C) to kill pathogens that are in the faecal matter, this is called thermophilic composting. Although some moisture is required in composting, sometimes there can more urine than is needed. Excess urine soaks through the compost pile resulting in a small amount of compost tea. Compost tea is nutrient rich so it can be collected and added to a compost pile or allowed to soak into the soil if conditions are suitable. The advantage of an internal composting toilet is that you never have to deal with raw waste which over the life time of the toilet is quite a major factor.

Capacity

The great advantage of a urine diverting toilet is that there is no maximum capacity of the unit. Since you are not expecting the waste to break down in the toilet there is no need to wait to empty the container. As long you change the container for an empty one the toilet can go on and on. In contrast using a composting toilet there is a max capacity. The composting process occurs in the unit and this takes time, about 6 weeks. Each internal composting toilet has been designed to process waste from a certain number of people into compost. This rating, in persons, is given on a constant or seasonal basis. For example the Sun Mar Excel is rated for 3 people on a constant basis and 6- 8 people on a seasonal basis. It is important to choose a composting toilet that has a capacity greater than, or equal to, the intended usage so that you get fully broken down compost. There is no issue with using the composting toilet too little and the units are designed to cope with no use part of the year.

Follow up

The great advantage of an internal composting toilet is that compost is removed from the toilet so you never have to deal with unbroken down waste. The thermophilic composting process kills off the pathogens and transforms the structure of the waste. It also reduces the volume of the solid waste to about 25% of it’s original volume. Millions of composting microbes consume the carbon in the waste leaving less solid material to remove. With the urine diverting compost toilet, little or no breakdown occurs in the unit so the waste is not reduced or broken down. This needs to be composted outside. This means that the emptying cycle is more frequent with a urine diverting toilet (every 2-4 weeks) than an internal composting toilet (every 2-6 months). The solid material that comes out of the urine diverting toilet needs a further 18 months to break down (can be faster if composting is managed using an hot composter) in line with best international practice. This composting needs to take place in a compost bin that is sealed at the base (pest proof) and has a lid to avoid flooding. So there is more follow up care required with the urine diverting toilet which is up to the owner to manage properly.
 

NickB

Full Member
Good information there Phil for anyone going down this route.
I walked past* smelled and cringed remembering emptying the cassette.
* At the show.
I'd been motorhomeless since September 2018... before that I had my old van 17years.
It felt SO good to be back in what that poster called her? TIN TENT.
 

NickB

Full Member
Anyone interested take a look on YouTube there are 100's of posts on the DIY construction.
At one point I was seriously considering getting a traditional cassette toilet and using it as the donor equipment for composting conversion in my new van.
It really is simple and environmental friendly.
 

wildebus

Full Member
Composting toilets seem like a great idea.

I have heard some worrying things about using Peat Moss as the composting material though (think it was lava eggs and the heat?). might be worth digging (ha!) into further just in case?
 

NickB

Full Member
Yes I've seen that mentioned as well.
Some say it should be handled with gloves.
Not sure now exactly why I went with Irish peat moss.
I think it must been something I read on one of the "humanure' enthusiasts websites. There was one where they had tables showing the pros and cons of every type of 'soak' material man could think of.
I bought a sterile 100 litre bale (that's the commpressed size) for anout £10 - £15 I worked out that was about 2-4 years worth.
BTW I used a scoop to sprinkle the peat moss over my recent personal contribution to sustainability.
I
 

wildebus

Full Member
Was ages since I last looked at this subject but the idea of using cat litter (fuller's earth specifically) seemed quite a popular idea? (not sure if it is one of the more expensive ones though?)
 

NickB

Full Member
That is exactly the idea. The guys who have done all the work have experimented with all sorts of stuff.
Your right cost comes into in as does how green are the various types of cat litter... how sustainable is moss peat it goes on and on, but from my point of view in the van, it uses no water, hope mine lasts 2+ months without emptying.
Poo is 80% water (eg dog poo after 4 days with no rain getts smaller and crumbles.) The bugs in my peat moss will think it's Christmas come feeding time.
 

wildebus

Full Member
That is exactly the idea. The guys who have done all the work have experimented with all sorts of stuff.
Your right cost comes into in as does how green are the various types of cat litter... how sustainable is moss peat it goes on and on, but from my point of view in the van, it uses no water, hope mine lasts 2+ months without emptying.
Poo is 80% water (eg dog poo after 4 days with no rain getts smaller and crumbles.) The bugs in my peat moss will think it's Christmas come feeding time.
I think this is what I heard .... Soon as you "feed" the peat .... :(

I thought Peat Moss was considered unsubstainable for its traditional uses (fertilizer and burning) but the amount for composting toilets would be a drop in the ocean (or the pan :) ).

Off-topic. I know they are called "composting toilets" but does anyone actually really use the removed product when refreshing it in any composting way ever? Tends to get bagged up and chucked in normal bins and ends up in landfill? So environmentally is it better or worse truth be said? The major benefit is really for the user and eliminating messy and more frequent disposal.
Which is no bad thing for the individual, but I do wonder if these systems are promoted as environmentally better options but in real-life use are the reverse?
 

NickB

Full Member
That is something that I'm thinking about now. Disposal?
I've got 3 conventional compost bins in my garden and several log piles... toads love the area underneath.
I'm probably going to tip it out when needed in a quiet area and build a log pile on it when get my next free tree or logs.
As long as it doesn't come into contact with ground touching food plants for two years it is OK.
 

wildebus

Full Member
I know in reality it is no different (well, I think it isn't!) but there is for some (me anyway, and I will be up front about that) a mental difference between using general compost and compost made from human waste matter.

Logical - not in the least.
Realistic - yes.

If I had a composting loo (and I have thought about it), it would 99% be (rightly or wrongly) emptied into a bin bag and then put into a wheely bin.
 

Squiffy

Full Member
As a matter of interest on that subject in the late 40's and early 50's potatoes from Egypt were imported into Britain, these potatoes were grown in human waste I know this as my father was station in Alexandria with my mother and older brother after the war and their hiring (House) was right next to some of the fields that they grew them in. My Mother had from that time never eaten potatoes unless she knew where they were grown 🤪 Phil
She also said she would never forget the smell
 

GEOFF

Full Member
Years ago, on a visit to my inlaws my FIL asked if the tomatoes in my salad were ok. I said fine thank you, but why do you ask. The reply was that the Toms had just appeared on their own in his dahlia patch and he had no idea how they got there. It transpired that he had used some "sludge" from the local sewage farm and the tomatoe seeds pass through the human digestive system!!!! I must say that the Toms tasted fine, and that there were no smells giving the game away. Geoff.
 

Auntyjan

Full Member
Good information there Phil for anyone going down this route.
I walked past* smelled and cringed remembering emptying the cassette.
* At the show.
I'd been motorhomeless since September 2018... before that I had my old van 17years.
It felt SO good to be back in what that poster called her? TIN TENT.
I was at Malvern last weekend and had to empty my contribution into the "concrete hole in the ground". It was decidedly soggy under foot around the area and your post has just made me decide to give a composting toilet a trial. We are back there for Busfest and the October Caravan Show so I will begin with them. Thank you
 

Debs

Full Member
Does anyone else on the forum have a composting toilet in their van?
I made my own dry (urine separate) one a few months ago and gave it (not literally) it's trial run over the last weekend in Malvern.
Worked fine!
*IF* anyone is interested I'm using Irish peat moss,with an Armitage Shanks Bakasan open front (horseshoe shaped) seat.
I have one, built it myself, been using it for about a year, and would never go back to a standard camper toilet. I definitely do not miss going to the elsan emptying point...yuk.
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NickB

Full Member
Love all the positives.👌 Great to hear them all.🚻
I'm surprised that no one has converted their cassette though.

Everything is there really just a separating seat and a pee tank needed..
I'd put money on some of the top of the market builders offering composting toilets within 5 years.
 

NickB

Full Member
Good work Debs.... what "soak" material are you using is that sawdust? Have you tried anything else?
 

wildebus

Full Member
Love all the positives.👌 Great to hear them all.🚻
I'm surprised that no one has converted their cassette though.

Everything is there really just a separating seat and a pee tank needed..
I'd put money on some of the top of the market builders offering composting toilets within 5 years.
I think all it needs is someone other then Natures Head or their main rival doing a deal with a major maker to make them cheaper (still >4x the price of a cassette jobby) and it could be a standard fitment for the European/UK market. The DIY options do really require a s***-stirrer I think?
I think the US is too wedded to their black tanks and just fitting a hose and opening a valve so don't have to deal with the messy business too much. But then again ....


There is a definite trend to Induction Hobs and Compressor Fridges in the US now Lithium Batteries are much more 'user-proof' and affordable in the high-end products, and I can see that trend coming in Europe (good weight saving as well).
 

NickB

Full Member
Absolutely I'm getting around the peak problem by giving my box a good 45° angle "back and fore" shake so far.
Regarding fridges & hobs might be worth a couple of new threads. I've put in a cruise elegance compressor and upgraded it myself with the smart energy controler. And a Wallas xc duo diesel hob of the van fuel tank.
 

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