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Treacodactyl

Small composting toilet

I've been thinking about the feasibility of using a composting loo in a garden shed or garage. Privacy is not a problem but space would be. So, would it be feasible to have a small self-contained composting loo that could be tucked away, then pulled out and used when required?

It would be ideal if I could buy something like a self-contained camping toilet as I think more people would use it. However, a quick google suggests they are around the 400 mark so it looks like a home-made one would be the way to go.

I'm thinking, a wooden box to contain a bucket, a seat on the top and then a lid with a reasonable seal. That doesn't sound difficult but will an average builders bucket be large enough? Without going into too much detail how long would it take the average person to fill up a black bucket? I'm mainly thinking about how much saw-dust would be required after each use. I suppose I'd have to find somewhere to complete the composting process - any ideas?
Barefoot Andrew

Re: Small composting toilet

Without going into too much detail how long would it take the average person to fill up a black bucket?


Such images Shocked
A.
Lorrainelovesplants

Can you also use ash from the fire to sprinkle on top after every visit?
Granted we dont get a lot of ash from a wood burn,but is this not another way to completely use it up?
sally_in_wales

Offhand, I think the ones at Ginkotrees use what are essentially 5 gallon brewing buckets as recepticals, half full of straw, then you put a handful of sawdust on top after every visit. When full, they go on a special compost heap.
Bulgarianlily

we use a lot of sawdust in ours, it is a 15 liter buckets and it gets emptied every two or three days for two people, but then it is the only loo we have. You don't have to worry about making it too airtight as the sawdust covers and prevents smells.
cassy

We use 50 litre ex-mango chutney barrels, in a wooden box with a conventional toilet seat on top.

For 2 people full-time plus occasional visitors, we 'produce' 40 litres of material a week. This is for 1 person's urine and 2 peoples faeces.

Once full, the barrel is emptied into a 0.9m3 composting bin. We fill 3 of these a year, so 1.35m3/person/year. We intend to leave the bin to compost for 2 years to be on the safe side in case we don't achieve good thermophillic composting, so we will need 3 sets of 3 bins (we're currently filling set 2). We have decided not to separate off all the urine, to add nitrogen to help to break down the sawdust but you would produce a smaller volume if you did.

Costs - the main costs have been the composting bins ~100 to make one set of three. We could have used pallets, but in case anyone ever complains, the composting area looks clean, tidy and rat proof. They're made with 4" x 1 1/2" timber with felted rooves. The barrels were 7.18 each delivered; timber and hinges for the toilet box was 36. We have a plastic dustbin beside the compost bins which stores a cheap watering can for rinsing after emptying and a plastic brush.

In total it cost approx 370 for everything, but it should all last years and years.

We buy big bales of sawdust for horse bedding which is cheap and nice to use but we've still to find out how it will break down.

Hope that's not *too* much information. Very Happy
Treacodactyl

Thanks for the replies. I can cope with as much information as possible but I know a few more delicate members might not. I'll draw the line at scientific measurement of some of the finer details though. Laughing

Hopefully it'll just be solids as I will collect and use urine separately. I know a compost toilet shouldn't smell so shouldn't need to be air tight but as it'll be in a garage used for other tasks and I'd like to keep flies out etc I'll aim for a reasonable seal.

Looks like the only problem will be composting. There will not be any space in our garden but I do have plenty of space in our woodland which is where the final compost will be used. However, I'm not sure if I'll need to abide by any specific animal waste/composting rules. I'd also like to compost our dog's waste at the same time so I would need to do that properly to kill off any bugs.
cassy

It might be easier to use the bucket lid as a seal when not in use, to avoid fly infestation. We screwed the toilet seat on to the plywood top and recessed the toilet seat hinges to allow it to sit flush on to the toilet seat, removing the rubber bumpers. It's an ok fit, but not a perfect seal. The plywood is hinged and that section lifts, taking the toilet seat and lid with it, for fitting and removing the barrel.
Nicky Colour it green

how much sawdust are you getting through a year?
cassy

We didn't start out using the bales last year; we were getting free sawdust from a local sawmill in variously sized bags but I reckon it would equate to 6 bales per year (I'll keep a closer count this year).

That's 1 bale per compost bin as soak when empting the barrels and 3 used as soak and cover material in the barrels as they're being used.

The bales are 43cmx37cmx78cm (0.12m3) and cost 7.25 + vat.

So for a year, 43.50 plus vat.

We're hoping to eventually use our own sawdust.
sally_in_wales

anyone using shredded paper in theirs in any proportion? Looking at the amount of junkmail I seem to put out for recycling or letters etc that get shredded, it might be usable as a soak layer in the bins mixed with sawdust?
cassy

We tried some shredded paper but it was not very good as a cover material IMHO and didn't prevent smell. We didn't try mixing it, but it could be useful as soak in the compost bins as you say.

If anyone is wondering how much space a composting toilet would take up in the bathroom, ours is 70cm wide, 47cm high and 62cm deep. This includes a compartment for soak material, so you could reduce the width to 49cm and you could reduce it further if you used a smaller diameter bucket and less robust carcassing (ours is built to withstand a nuclear attack Laughing ). There are some lighter weight models in Chapter 6 of The Humaure Handbook.
Ginkotree

The straw does break down very well,better than paper at the bottom of the buckets. Brewing buckets seem to be a very comfortable sitting height and have tight lids for when transporting the bucket to the compost site.,I add well rotted manure with worms to the composting units and adding shredded nettles can also aid the process .
The 'Sealing', I think is not necessarily in the lid closing tightly but in the covering of the "Offering". In all the years of running the bin method I have not had a fly or smell problem if the covering is done properly. Somehow, this stops smells and flies.I suspect flies would be attracted to uncovered "offerings" On days when we have many visitors I use grass cuttings rather than sawdust as there is so much extra bulk being added to the bin in one day. the Loos tend to smell of grass cuttings.Most visitors are generous with the sprinkling of grass so everything works well...Most folk are really pleasantly surprised and have said it is better than using some public conveniences.
We also place bunches of herbs in the room which is simply there as a Nice thing to do but not necessary.
We have spring water to rinse the bins and once clean I leave them in the sunshine to air.
Bulgarianlily

The sawdust breaks down into lovely compost BUT we don't collect the urine seperately and I think that if you did this the compost would be too dry to rot down. I think the urine is needed for it's nitrogen content also in the mix. Otherwise you would have to add some green stuff at some point. There is NO fly problem as long as there is sawdust on top. We have been using this system for the last four years. The other thing you need is to have a bucket cleaning area well set up. I wish I could find a stainless steel bucket of the same size (with a lid for removel) as the plastic buckets eventually smell themselves as they build up scratches that can't be well cleaned and we replace ours yearly.

How do you move the big 50 liter buckets?
Lorrainelovesplants

Those who have already installed these...could you give suppliers website/contact details?

We are ready to do this in April! Smile
RichardW

2 & 1/2 people will fill a brewers barrel in about a week with no urine separation using sawdust for cover with a light dusting in the bottom to start you off. Having guests sees it filled much quicker as they tend to over cover.

Planning on separating the urine soon so we will see how much this affects the fill time. Oh & plan on having 3 compost areas. One being filled, one just filled & sealed plus one already filled & rotting. Dep on sawdust used it could take a while to compost. Dont do what we did & use cedar. The first bin took a year to fill & have been full for 1 1/2 years & is still not composted (well on the top any way). I think we need more vegetation to help things along.
Treacodactyl

I'm still having trouble tracking down anything to do with UK regulations to do with composting human waste, I can't believe there aren't any. Shocked

For a small system I would make a lidded compost bin to routinely empty the bucket into, and I can add separated urine, dog waste etc. For our own benefit I'd like to do it properly but can't find anything official.

Does anyone know of any regs that should be followed or can I do what I want?
earthyvirgo

I'm still having trouble tracking down anything to do with UK regulations to do with composting human waste, I can't believe there aren't any. Shocked

For a small system I would make a lidded compost bin to routinely empty the bucket into, and I can add separated urine, dog waste etc. For our own benefit I'd like to do it properly but can't find anything official.

Does anyone know of any regs that should be followed or can I do what I want?


Very little we could find when we were doing our planning app.

Vegplot is out and about today but I'll point this thread out to him when he gets back.

It was the least problematic area of our application, once planning had got over the shock that someone actually wanted to do it in their home.

EV
Treacodactyl

I'm still having trouble tracking down anything to do with UK regulations to do with composting human waste, I can't believe there aren't any. Shocked

For a small system I would make a lidded compost bin to routinely empty the bucket into, and I can add separated urine, dog waste etc. For our own benefit I'd like to do it properly but can't find anything official.

Does anyone know of any regs that should be followed or can I do what I want?

Very little we could find when we were doing our planning app.

Vegplot is out and about today but I'll point this thread out to him when he gets back.

It was the least problematic area of our application, once planning had got over the shock that someone actually wanted to do it in their home.

EV

Yes please. There's regulations on composting animal waste and on septic tanks etc, but I can't find anything specific to composting toilets. I'm not sure who to even ask.
RichardW

I think the advice is to not put dog waste in any composter that is going to be used on crops.

Make sure you allow for any leachate that is going to come out of the base of the pile.
Treacodactyl

I think the advice is to not put dog waste in any composter that is going to be used on crops.

Make sure you allow for any leachate that is going to come out of the base of the pile.

I intend to use the compost around the base of trees so it wouldn't come into direct contact with a crop. Also, thinking about dog waste vs human waste, our dog is routinely wormed whereas I've not been wormed since I was a tiny child - who's the most likely to spread a disease? Admittedly I don't eat deer droppings and other assorted nasties. Laughing

I would make allowance for any leachate, and would aim to have none/as little as possible by covering the composter, but I don't know if that would meet the regs if any exist.
vegplot

I'm still having trouble tracking down anything to do with UK regulations to do with composting human waste, I can't believe there aren't any. Shocked

For a small system I would make a lidded compost bin to routinely empty the bucket into, and I can add separated urine, dog waste etc. For our own benefit I'd like to do it properly but can't find anything official.

Does anyone know of any regs that should be followed or can I do what I want?

Very little we could find when we were doing our planning app.

Vegplot is out and about today but I'll point this thread out to him when he gets back.

It was the least problematic area of our application, once planning had got over the shock that someone actually wanted to do it in their home.

EV

Yes please. There's regulations on composting animal waste and on septic tanks etc, but I can't find anything specific to composting toilets. I'm not sure who to even ask.

It's down to the Environment Agency and their take on it as long as it's for residential purposes they don't want to know - just go ahead and do it. All we needed to show was how we dealt with the wet waste (urine) and for that simply stated that we were going to use a soakaway.

Building regs were a little more inquisitive and were asking for technical specification of ready made loos but they're happy as long as the EA were.

In a nutshell there isn't a problem for private residential use.

To quote the EA
Quote:
Composting toilets use natural processes to convert waste matter into compost. They are useful at remote sites, such as nature reserves, where there is no public sewer or mains water supply. They may require maintenance and the addition of materials such as sawdust to aid the composting process. Some may produce concentrated fluid fertiliser or dry compost for use. These should not be discharged to a watercourse.
cassy

Building regs were a little more inquisitive and were asking for technical specification of ready made loos but they're happy as long as the EA were.
Did you have to submit plans with a ready made loo in the end or have you given details of a home made one? (This is a problem I will be coming up against shortly.)
vegplot

Building regs were a little more inquisitive and were asking for technical specification of ready made loos but they're happy as long as the EA were.
Did you have to submit plans with a ready made loo in the end or have you given details of a home made one? (This is a problem I will be coming up against shortly.)

Building regs asked for technical details, we gave them some examples but explained quite clearly what a composting toilet was. They were a little bemused, didn't know quite how to handle it at that point gave up and said that as long as EA were okay with it then so would they.

If it's not part of a larger project, like ours is, then I wouldn't even mention it. Just do it. You won't be breaking any regulations if the solid waste is indeed being composted and wet waste is treated appropriately.
Treacodactyl

Thanks VP, that was roughly my conclusion - speak to the Environment Agency. As I'll not be doing any building work there's no reason to speak to building control.

It seems a bit strange that we should all be thinking along these sorts of lines but there's no help from the powers that be.

I also found comments that suggest it's fine to run urine to a soakaway but wouldn't that result in a build up? I don't plan to do that, I'll use it either watered around plants or on various composts, but I'm a bit curious to know why it's allowed.
cassy

They were a little bemused, didn't know quite how to handle it at that point gave up and said that as long as EA were okay with it then so would they.
Thanks, that makes sense. It is part of the building warrant for the house so we need to do it properly, so I'll approach SEPA for approval of the system, then hopefully building regs will base their view on that. Very Happy
cassy

How do you move the big 50 liter buckets?
I've just weighed a full one (it's all fun in this house!) and it was 26kg. We usually carry it out of the caravan (it has a robust handle on each side) and lift it onto a wheelbarrow. We will have to use a lighter weight system when we get old.
vegplot



I also found comments that suggest it's fine to run urine to a soakaway but wouldn't that result in a build up?

Urine isn't pathogenic in the same way that solids are. There's nothing to build up expect mineral deposits and for a soak away that's never a problem.
Treacodactyl



I also found comments that suggest it's fine to run urine to a soakaway but wouldn't that result in a build up?

Urine isn't pathogenic in the same way that solids are. There's nothing to build up expect mineral deposits and for a soak away that's never a problem.

It not disease build up that concerns me but the build up of mineral deposits and nitrates etc, or the fact they'll leach out into the water table. Mind you, with the oncoming peak-phosphate crisis I can see people digging up soakaways in future. Laughing
vegplot

Try it. If in 130 years time you find a problem then dig another soakaway. Treacodactyl

Not me, urine is too valuable to pour away, it'll be used as fertiliser.
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