Composting Toilet Question

[Doodlebug]

Without meaning for everyone to get their popcorn out...

 

I will be fitting a diy composting toilet soon. It will consist of a normal toilet seat, which I have modified to separate off the liquids to a large jerry can, which can then be carried to wherever it can be disposed of. (This also has an electric flush made from a windscreen washer pump)

 

Underneath all this will be a pretty large storage box, (I think its 65l) which is for the solids.

 

It will be covered over with course sawdust, to which I will add some sort of fragrance oil to make it smell nice.

 

I will then do what is needed when it comes to emptying it, and will put a lid on the box, and leave it to fully decompose (I'm considering planting something in it but thats another story)

 

So here is my question. I understand that it shouldn't smell (well less than an elsan anyway) but whilst I am building it should I make an extractor to suck bathroom air down the toilet and outside the boat or is this just not needed.

 

If so, should I use a little computer fan and have it on constantly, or get a large extractor fan and rig up a circuit so that when you are in the toilet, it is sucking all the air out the boat. (I see this as a problem in winter with loosing all my heat)

 

Or would I be better to have a computer fan and a load of active charcoal to remove any smells?

 

Also I have read conflicting advice as to whether the compost should be wet or dry. Wet allows decomposition yet also creates more smell. Should the compost be perfectly dry to dehydrate the solids or should it be moist?

 

Thanks for any ideas

 

Doodlebug

 

 

[bottle]

Not studied it that much but I believe most of the commercial ones have a heater and a vent.

 

Usually have one of those things on top that rotate automatically in the wind.

[bizzard]

Without meaning for everyone to get their popcorn out...

 

I will be fitting a diy composting toilet soon. It will consist of a normal toilet seat, which I have modified to separate off the liquids to a large jerry can, which can then be carried to wherever it can be disposed of. (This also has an electric flush made from a windscreen washer pump)

 

Underneath all this will be a pretty large storage box, (I think its 65l) which is for the solids.

 

It will be covered over with course sawdust, to which I will add some sort of fragrance oil to make it smell nice.

 

I will then do what is needed when it comes to emptying it, and will put a lid on the box, and leave it to fully decompose (I'm considering planting something in it but thats another story)

 

So here is my question. I understand that it shouldn't smell (well less than an elsan anyway) but whilst I am building it should I make an extractor to suck bathroom air down the toilet and outside the boat or is this just not needed.

 

If so, should I use a little computer fan and have it on constantly, or get a large extractor fan and rig up a circuit so that when you are in the toilet, it is sucking all the air out the boat. (I see this as a problem in winter with loosing all my heat)

 

Or would I be better to have a computer fan and a load of active charcoal to remove any smells?

 

Also I have read conflicting advice as to whether the compost should be wet or dry. Wet allows decomposition yet also creates more smell. Should the compost be perfectly dry to dehydrate the solids or should it be moist?

 

Thanks for any ideas

 

Doodlebug

 

 

Eat plenty of tomatoes and you'll not need to plant anything in it. The seeds are very tolerant, pheeew!

[Caprifool]

Our Separett has a fan only. No heater. The fan also draws air out from the urine container. Skip the fragrant oil. They often mess with the bacteria that you actually want for breaking down the compost. And are not needed. When you changed the bin to store it, give it a couple of good shovels of soil, full of lovely organisms that will help. It is pretty dry, which makes it odourless. So I water the bin with about 500 ml before sticking the lid on.

 

Edit to add: If you like a less DIY look and feel to it, you can check out the Separett Privy 500 and 501 kits. http://littlehouse.co/

Edited July 26, 2013 by Caprifool

[Doodlebug]

Eat plenty of tomatoes and you'll not need to plant anything in it. The seeds are very tolerant, pheeew!

 

My Grandad used to live near to a sewage plant which sold compost. He said it grew the best tomatoes - especially since you didn't have to pant any seeds!

 

Good point with the fragrance oils, as part of a product i'm taking to market (hopefully) i'm looking at the antibacterial properties of orange oils, I haven't extended research to other types yet.

 

What would happen caprifool if the fan wasn't on, would it smell? I think I will put one in anyway, the problem is finding a place for it to exit the boat.

[Caprifool]

I would imagine, a compost toilet with no fan....if a separating one, would smell kinda earthy and "rustic". But not the horrible "sewage" like smell you get when urine and feces are mixed. Ours in the house is a 240V one, and we've had a few power cuts, like a day or two long. Wasn't a huge problem. Noticeable yes, but not horrible. I've used pump outs that smelled worse 24/7. So a temporary break down or flat battery on a 12 Volt compost toilet on a boat wouldn't be a problem. Not for me anyway....

Edited July 26, 2013 by Caprifool

[OldGoat]

In my yoof, we holidayed in a WW1 hut in the country. The loo was a mahogany seat with a special heavily galvanised bucket underneath. Under pain-of-death we were told to we in a pot and only use the bucket for solids - well covering them with a layer of sawdust after use.

It never smelt even after a good week's use by a family of five.

The secret being - keep it dry. 'suppose the wind between the cracks in the hut kept everything well ventilated..

 

I still have the bucket....

 

 

[smileypete]

With sawdust it helps if it's a little bit rotten, by leaving out in the rain to get damp.

 

There's a well known compost loo handbook, can be downloaded for free if you want:

 

http://humanurehandbook.com/manual.html

 

cheers, Pete.

~smpt~

[Ex- Member]

Without meaning for everyone to get their popcorn out...

 

I will be fitting a diy composting toilet soon. It will consist of a normal toilet seat, which I have modified to separate off the liquids to a large jerry can, which can then be carried to wherever it can be disposed of. (This also has an electric flush made from a windscreen washer pump)

 

Underneath all this will be a pretty large storage box, (I think its 65l) which is for the solids.

 

It will be covered over with course sawdust, to which I will add some sort of fragrance oil to make it smell nice.

 

I will then do what is needed when it comes to emptying it, and will put a lid on the box, and leave it to fully decompose (I'm considering planting something in it but thats another story)

 

So here is my question. I understand that it shouldn't smell (well less than an elsan anyway) but whilst I am building it should I make an extractor to suck bathroom air down the toilet and outside the boat or is this just not needed.

 

If so, should I use a little computer fan and have it on constantly, or get a large extractor fan and rig up a circuit so that when you are in the toilet, it is sucking all the air out the boat. (I see this as a problem in winter with loosing all my heat)

 

Or would I be better to have a computer fan and a load of active charcoal to remove any smells?

 

Also I have read conflicting advice as to whether the compost should be wet or dry. Wet allows decomposition yet also creates more smell. Should the compost be perfectly dry to dehydrate the solids or should it be moist?

 

Thanks for any ideas

 

Doodlebug

 

 

 

Hi Doodlebug

 

First off you need a chimney through the boat roof, compost needs aerating and the chimney has a natural draw and will remove smells. If you use some plastic 4 inch waste pipe, even 5 inch, you can insert a comp fan to boost this draw. You also need to vent the composting bin.

 

The other thing is emptying, you need to rig some kind of removable drawer/box that you can easily remove broken down waste. Do not use sawdust use light softwood shavings, these help oxygenate the compost which is essential for the survival of microbes, coarse peat moss is also good.

 

Garrota compost maker is also good stuff especially to get composting going and speed it up. A big 5 kilo tub is around £8 quid, will easily last a year.

 

Look carefully at compost toilet designs, Sun mar have lots of info. Remember your compo loo is on a boat, so there are big diferences between designs for compo loos on land.

[peterboat]

All good info I bought my seperatte villa and that has a computer fan in it. When I was in dry dock the other week I was working by the loo exhaust and could smell some pong but it was not bad but I suspect that if the fan wasnt running in the heat we have had over the last few weeks the loo would smell so deffo for the fan and exhaust

 

Peter

[Doodlebug]

Thanks everyone for the comments, I am less worried about the smell now and will fit some sort of ducting, since the toilet is right under one of my top boxes.

 

An idea I have running through my head is to pump the 'smelly air' from the toilet area, and to pump it through an air stone, into a pretty looking glass tube. The water in the tube would be mixed with a small amount of antibacterial stuff, and have fragrance oils added to it. The water will (according to my research) catch the bacteria and smell, and filter the air. Furthermore it means that when showering, the steam will be dehumidified, and more to the point I wont be pumping my nice warm air outside.

 

Another one of my crazy ideas I know, but its worth testing it out, the idea has been used before for air filtration.

[Strads]

We have a composting loo, for last 5 years plus..

we use normal compost but very light dusting once used..

 

ours is an ll in one, fluids and solids in a big plastic base.

 

there is a very slight whiff occasionally,,, it vents through a plastic 4 inch di pipe that has a fan blowing from the loo base... it has 2 speed selections to help the evaporation..

 

our pipe exits under one of the exisiting mushrooms !! less metal to cut, the fan drys the roof on a wet day and it smells more on the outside than inside.. a hint of fullers earth,

 

inside the loo dosnt smell, no one has complained about the fitting since new, and having used other boats, with drop through and cassettes both smell more..

we also have a mascarator pump out to a separate tank, again, no smell,, except immediately after its pumped out, when the contents are fully disturbed,,

it lingers about 5-10 minutes,,,

 

so try it, some venting will sort the issue, go for it!

[Starcoaster]

Two hire boats near me have composting bogs. When the fans have been off for a few days they do smell vaguely sewage-y from a few feet away outside. I am told inside is worse, obvs!

I don't smell them at all from the outside when the fans are running as they should.

[Canal Shop Man]

It is sometimes possible to have a composting toilet in a boat without using a fan, but you need to ensure really good ventilation to avoid smells. It is very important to separate urine at source to keep it pure and unpolluted, then it can be disposed of usefully and easily.

 

If you keep urine separate from soilds then you won't need to add anything to the solids tank each use, bearing in mind that the more you add the sooner it will get full and the more you will have to store till composted. It is not necessary to use any heaters, but the warmer the toilet is the faster the composting.

 

Above all, keep it simple. Adding fancy ducts with liquid in or other chemicals, whether natural or artificial will just complicate matters and make it more likely to go wrong.

 

Whilst those who have never tried composting toilets may criticise them, few who have properly installed composters will complain about them and most will rave about them.

 

As some of you may know, I have been supplying composting toilets for boats for 15 years or so and can provide everything from just urine separators for those who want to build their own to fully equipped toilets. PM me if you want to know more as any more here may be considered advertising.

[Ex- Member]

It is sometimes possible to have a composting toilet in a boat without using a fan, but you need to ensure really good ventilation to avoid smells. It is very important to separate urine at source to keep it pure and unpolluted, then it can be disposed of usefully and easily.

 

If you keep urine separate from soilds then you won't need to add anything to the solids tank each use, bearing in mind that the more you add the sooner it will get full and the more you will have to store till composted. It is not necessary to use any heaters, but the warmer the toilet is the faster the composting.

 

Above all, keep it simple. Adding fancy ducts with liquid in or other chemicals, whether natural or artificial will just complicate matters and make it more likely to go wrong.

 

Whilst those who have never tried composting toilets may criticise them, few who have properly installed composters will complain about them and most will rave about them.

 

As some of you may know, I have been supplying composting toilets for boats for 15 years or so and can provide everything from just urine separators for those who want to build their own to fully equipped toilets. PM me if you want to know more as any more here may be considered advertising.

 

It;s not correct to say you cannot compost with urine added, there are several compost loos on the market that you don't need to separate the urine, these type units will absorb much of the urine into the compost which keep it moist but also have systems to drain of excess urine from the compost so it doesn't get too wet, this flows to the base of the unit where it basically evaporates over time. Chimney and air flow units can do this quicker and heaters quicker still. There is an emergency overflow too should too much urine end up in the bottom of the unit, this then drains off into containers varying in size depending on model or general preference. We have a 10 litre container to drain into which has only needed emptying 4 or 5 times in 9 years. They rarely overflow though if you have the correct size unit for your needs, but can do if you have guests.

[peterboat]

Hi both of you are right mine is the seperating type but i have seen the other version in a house but also I have seen an amount of the non seperaters for sale and I have seen a large amount of complaints about them so for me it would be better to go the seperate route

 

Peter

[mrsmelly]

Apparently because of this thread manufacturers and suppliers have all run out of composting bogs. They are known to be so popular that is why nearly all boats on the system have them fitted. The days of the cassette bog and pumpout are numbered. All 7 of the boat owners in the uk with composting toilets are guilty as charged for promoting the device and bankrupting other bog manufacturers. !! Shame on you all.

 

Tim

[Caprifool]

Thank you Mr Smelly for that educated update. How ever those of us who have grown up with outdoor bogs, the seventies horrible non separating compost toilets and now have had a modern Separett for years "might" just have enough experience to actually be able to give some sound advice and true statements about every day use of modern composting toilets.

[Ex- Member]

Thank you Mr Smelly for that educated update. How ever those of us who have grown up with outdoor bogs, the seventies horrible non separating compost toilets and now have had a modern Separett for years "might" just have enough experience to actually be able to give some sound advice and true statements about every day use of modern composting toilets.

 

Hi Caprifool

 

We've had a non separating compo loo for 9 years, I did a lot of research before buying our sun-mar and never came across any neg feedback about them, did you have a particular model that was problematic?

 

You do have to be more careful with non separate units though, as well as coarse sawdust we also use booster microbes and occasionally peat moss and another product lake sandy ash called Garotta that speeds up composting too.

 

It's composting really well at the moment in this hot weather LOL

[Caprifool]

Sorry, can't help you there. It was when i was a kid and in my teens. Had more important things to think about, like Slade and Gary Glitter :-D But my nan had three. One HUGE one that stank, leaked and would go all mushy if we had guests. One smaller one that stank, leaked and would overflow with urine when we had guests. And one smaller one which had rotor blades that slowly turned the compost, that didn't stink but made a lovely lump of poo dough when we had guests :-) I've used two Separett's for every day use for years now. And they are completly different creatures. Been very happy with them.

 

But wiggling my toes, listening to the owls on the out door bog is my favourite any day.

[Capt.Golightly]

it still seems like an expensive bucket to me, the urine separator and fan is clever but doesn't justify £400 in my view ....the only thing which makes it a "composting" toilet is the word "compost" and a disposable "compost" bag which are £1.29 for 20 at garden centres...though I wouldn't knock it for anyone if it works for them.

[Doodlebug]

it still seems like an expensive bucket to me, the urine separator and fan is clever but doesn't justify £400 in my view ....the only thing which makes it a "composting" toilet is the word "compost" and a disposable "compost" bag which are £1.29 for 20 at garden centres...though I wouldn't knock it for anyone if it works for them.

 

Thats why I see no reason why anyone should pay for one.

 

The one i've made is made using 25mm exterior ply to make a kind of box. This is then tiled with white tiles.

 

The toilet seat was £10, and underneath to separate the urine is a rather perfectly shaped IKEA mixing bowl which has been cut so it sits at an angle. There is a tube from the bottom which came from our washing machine and goes into a 10l jerry can, and solids go into a very large storage box. (twice the size of the ones you get with the proper toilets)

 

The fan is self explanatory and the flush is made using a car windscreen wiper pump.

 

Its not been used for that long but i'm already pretty impressed that it doesn't smell of anything.

 

Time will tell as to how it goes but my research suggests I should be ok.

 

I will eventually post pictures.

 

Cheers

 

Doodlebug