Portable Composting toilets,Very Very Green

[Seasoned Oak]

Been researching portable self contained toilets for My Camper And A cabin in the Woods with no Septic system.Seems you can get a very good portable for $100-150. Problem is of course how often to empty ,not a pleasant job. AND you need to find somewher to empty it(not always easy)
While searching i ran across something new COMPOSTING TOILETS.
While pretty pricey $1000 -$1500 these things are amazing. All self contained,No odors,easy to use,easy to keep clean no water needed,second compartment for composted material, some reviews state with 2 people using could go months before emptying,and at that point the material is
100% Compost. Read a boatload of reviews and the vast majority using these things are very pleased with their performance.
One other point, the composting ones are not exactly portable as you need to hook up a vent pipe to it and an excess liquid drain hose.But with my own small community struggling with a $210 Million Mandate To build a new sewer plant and forecasting $100 per month in sewer usage fees, perhaps there are other choices.
It don't get much greener than this.

 

[Delta-T]

these composting toilets are pretty cool. the Squam Lakes Natural Science Center, in Holderness NH, has them on site with a little interactive display board that lights up to show you how it works. Dont be fooled by the "odor-less" tag line, it doesn't smell like pounds of feces, but it still smells like any public bathroom.

 

[Seasoned Oak]

these composting toilets are pretty cool. the Squam Lakes Natural Science Center, in Holderness NH, has them on site with a little interactive display board that lights up to show you how it works. Dont be fooled by the "odor-less" tag line, it doesn't smell like pounds of feces, but it still smells like any public bathroom.

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In the user reviews iv read no one claim their s any odors ,if fact most of them comment about the lack of any odors. DOnt own one myself just researching at this point. Mfg claims in their product operation description,that if you get any odors you've done something wrong as there is an air vent that's supposed to flow only one way ,intake from the room and exhaust up the vent pipe.

 

[ROBERT F]

Dont overlook the incinerating toilets! they have their proper aplications aswell.

 

[Delta-T]

these composting toilets are pretty cool. the Squam Lakes Natural Science Center, in Holderness NH, has them on site with a little interactive display board that lights up to show you how it works. Dont be fooled by the "odor-less" tag line, it doesn't smell like pounds of feces, but it still smells like any public bathroom.

=====================
In the user reviews iv read no one claim their s any odors ,if fact most of them comment about the lack of any odors. DOnt own one myself just researching at this point. Mfg claims in their product operation description,that if you get any odors you've done something wrong as there is an air vent that's supposed to flow only one way ,intake from the room and exhaust up the vent pipe.

I dont think the smell stems from the actual composting bit, more just that you still have a urinal or toilet that has no water in it that can't realistically get rid of every drop of liquid that is.......evacuated into it. Like I said, its not any different that any other bathroom that sees public use. Unless of course the smell is from peeps who cannot aim very well.

 

[dougstove]

It is completely feasible to have dry toilet system where no odour is emitted from the opening of the seat.
The key is to have the waste reservoir vented only to a chimney system that is high enough, to generate enough draft, to keep air and smells flowing down into the seat opening, into the reservoir and out the chimney.
(I suppose somewhere with dead calm might suffer some back drafting, but dead calm is rare.)

Most outhouses are however built and designed backwards; lots of ventilation high up in the shed, and no ventilation from the waste tank. So the chimney effect in the top of the shed pulls smells out of the waste tank, up out of the seat opening, and past your nose.

Some outhouses in Africa are now actually designed to act as effective fly traps, operating on a similar principal.

 

[Seasoned Oak]

It is completely feasible to have dry toilet system where no odour is emitted from the opening of the seat.
The key is to have the waste reservoir vented only to a chimney system that is high enough, to generate enough draft, to keep air and smells flowing down into the seat opening, into the reservoir and out the chimney.
(I suppose somewhere with dead calm might suffer some back drafting, but dead calm is rare.)

Most outhouses are however built and designed backwards; lots of ventilation high up in the shed, and no ventilation from the waste tank. So the chimney effect in the top of the shed pulls smells out of the waste tank, up out of the seat opening, and past your nose.

Some outhouses in Africa are now actually designed to act as effective fly traps, operating on a similar principal.

One of the units i looked at had a small electric fan that made sure the air was going in the right direction. Others (cheaper models relied on the draft principal) Depends if you have electric available year round.

 

[dougstove]

Some of the composting units I have seen use a van to evaporate the water content.
Excess water (urine) input relative to solids is a common imbalance with human waste composting.

Some people use the straw bale solution; males pee on a straw bale that auto-composts, with straw carbon balancing out the urine nitrogen. Only solids and female urine go in the composting toilet.

 

[btuser]

OK, that's a guy who knows his sh*t.

I started looking at these about 10 years ago when the family got the itch for a camp. My plan was to pick up a non-buildable (ie, not enough room for well+septic) for cheap and do the self-sufficient thing with rain water cistern for grey water/irrigation and a composting/incinerating toilet. Do it all up with some 12V solar and I'd be on the waterfront for cheap. Nice thing about a self-sufficient house/camp would be lower taxes, no recurring costs from utilities, and I wouldn't have to worry about freezing temperatures.

 

[vvvv]

u need a chit eating dog?

 

[oldspark]

u need a chit eating dog?

I knew it was going to be good.

 

[mesuno]

Have you seen the Humanure Handbook?

He has a great system for composting human waste. Rather than drying out the waste, which most self-contained systems do, you use a load of sawdust. The sawdust helps balance the carbon-nitrogen ratio (as in any compost heap) which stops the whole thing nasty. With the right C/N ratio your manure undergoes hot composting which kills all pathogens.

The design is simple - basically just a toilet seat with a bucket under it. Part fill the bucket with sawdust, use just as you would a normal toilet. The only difference is that when you are done you "flush" with a scoop of fresh sawdust. This covers anything unsightly, completely preventing odours.

Once a week or so, depending on the number of people and size of bucket, you empty the bucket into your compost heap. Even the emptying isn't an unpleasant experience as the odour is essentially absorbed by the sawdust. At worst it will smell a bit like hamster cage!

I've had a lot of experience using these, including for remote camps with 50+ school children. They don't even end up with the usual "public toilet" aroma that others described above.

Mike

 

[Seasoned Oak]

Have you seen the Humanure Handbook?

He has a great system for composting human waste. Rather than drying out the waste, which most self-contained systems do, you use a load of sawdust. The sawdust helps balance the carbon-nitrogen ratio (as in any compost heap) which stops the whole thing nasty. With the right C/N ratio your manure undergoes hot composting which kills all pathogens.

The design is simple - basically just a toilet seat with a bucket under it. Part fill the bucket with sawdust, use just as you would a normal toilet. The only difference is that when you are done you "flush" with a scoop of fresh sawdust. This covers anything unsightly, completely preventing odours.

Once a week or so, depending on the number of people and size of bucket, you empty the bucket into your compost heap. Even the emptying isn't an unpleasant experience as the odour is essentially absorbed by the sawdust. At worst it will smell a bit like hamster cage!

I've had a lot of experience using these, including for remote camps with 50+ school children. They don't even end up with the usual "public toilet" aroma that others described above.

Mike

My only question is haw does it handle liquid waste (urine) or is it not advisable to urinate into this mixture?

 

[dougstove]

Urinating in a sawdust + feces bucket is fine, if the volume of urine is small.

The problem is that in normal use the relative volume of urine input compared to feces+sawdust is too large.
The urine swamps the system, blocks any aeration and leads to the typical disgusting pit toilet syndrome at campgrounds, with a pit of turds and paper swimming in a pool of pee.

That is why having a separate, high volume carbon rich receptacle (like a straw bale) is good for urination.
It cuts down on the excess liquid input into the main turd system, where hot composting and odour control is most important.

Normally, urine does not transmit significant pathogens, and so hot composting is not as important, and controlling run off from the urine receptacle is not as important (from a health perspective - still lots of possibilities for excess nutrient enrichment of adjacent water bodies).

Old fashioned outhouses let the liquid percolate away, while (roughly) composting the solids. People often added sawdust to balance out the C/N/P ratio. The pit filled only very slowly.

I have a theory that our primate origins make our minds deficient in dealing sensibly with human waste:
'If you live in Tree, it does not matter where you Wee'.

Intelligent cats with thumbs would deal with waste better than us.

 

[Wallyworld]

Have you seen the Humanure Handbook?

He has a great system for composting human waste. Rather than drying out the waste, which most self-contained systems do, you use a load of sawdust. The sawdust helps balance the carbon-nitrogen ratio (as in any compost heap) which stops the whole thing nasty. With the right C/N ratio your manure undergoes hot composting which kills all pathogens.

The design is simple - basically just a toilet seat with a bucket under it. Part fill the bucket with sawdust, use just as you would a normal toilet. The only difference is that when you are done you "flush" with a scoop of fresh sawdust. This covers anything unsightly, completely preventing odours.

Once a week or so, depending on the number of people and size of bucket, you empty the bucket into your compost heap. Even the emptying isn't an unpleasant experience as the odour is essentially absorbed by the sawdust. At worst it will smell a bit like hamster cage!

I've had a lot of experience using these, including for remote camps with 50+ school children. They don't even end up with the usual "public toilet" aroma that others described above.

Mike

My parents used peat moss instead of saw dust

 

[mesuno]

Urine is no problem - you just keep covering to make sure that there is plenty of sawdust in place. You don't need to maximise the volume of human waste in the bucket after all. You need to be able to carry it! If you have a few flakes of sawdust swimming in a bucket of wee you are definitely doing it wrong!

If in doubt, cover it with more sawdust.

We get a 1m^3 bag of sawdust from a local timber yard which lasts us about a year.

Also, you want to change the buckets before they get too full/heavy. Waiting until they are full to the brim is definitely not pleasant or a good idea. I guess what it comes down to is a change of mindset - you can't simply flush and forget any more, it takes a little time to learn the system. But I guess people here should be in tune with that attitude anyway.

 

[Seasoned Oak]

Have you seen the Humanure Handbook?

He has a great system for composting human waste. Rather than drying out the waste, which most self-contained systems do, you use a load of sawdust. The sawdust helps balance the carbon-nitrogen ratio (as in any compost heap) which stops the whole thing nasty. With the right C/N ratio your manure undergoes hot composting which kills all pathogens.

The design is simple - basically just a toilet seat with a bucket under it. Part fill the bucket with sawdust, use just as you would a normal toilet. The only difference is that when you are done you "flush" with a scoop of fresh sawdust. This covers anything unsightly, completely preventing odours.

Once a week or so, depending on the number of people and size of bucket, you empty the bucket into your compost heap. Even the emptying isn't an unpleasant experience as the odour is essentially absorbed by the sawdust. At worst it will smell a bit like hamster cage!

I've had a lot of experience using these, including for remote camps with 50+ school children. They don't even end up with the usual "public toilet" aroma that others described above.

Mike

One other question i have on this subject is ,How does the mixture undergo " Hot Composting" when there is a lid on it. Does not there need to be ventilation and a regular mixing of the contents to encourage composting, as with garden composter tumblers. It would seem that composting is not possible while the mixture is in the bucket without a supply of oxygen.

 

[mesuno]

The system isn't sealed - you use the bucket to collect from the toilets and then empty them into your main compost heap with your garden waste. The humanure spends only a few days in the bucket in the house before being emptied and hot composting really gets going once it has been emptied in the heap.

As far as turning the heap goes - we never bother. It is a lot of extra sweat effort for marginal gains. Turning the heap is supposed to speed up composting as you get usable compost sooner, but the final quality isn't noticably better. You do find a few pieces on the outside of the heap don't quite compost fully, but they just get chucked into the bottom of the next heap. Turning a heap can also partly compensate for a poor C/N balance in the heap, but this is not normally a problem in a heap with humanure.

Do a google search for the humanure handbook - you can download it for free, or buy a printed version from the author.

Mike

 

[Seasoned Oak]

The system isn't sealed - you use the bucket to collect from the toilets and then empty them into your main compost heap with your garden waste. The humanure spends only a few days in the bucket in the house before being emptied and hot composting really gets going once it has been emptied in the heap.

As far as turning the heap goes - we never bother. It is a lot of extra sweat effort for marginal gains. Turning the heap is supposed to speed up composting as you get usable compost sooner, but the final quality isn't noticably better. You do find a few pieces on the outside of the heap don't quite compost fully, but they just get chucked into the bottom of the next heap. Turning a heap can also partly compensate for a poor C/N balance in the heap, but this is not normally a problem in a heap with humanure.

Do a google search for the humanure handbook - you can download it for free, or buy a printed version from the author.

Mike

Im wondering why no smell while in the bucket ,i guess the sawdust is the trick,absorbs moisture as well as smell, this is the best idea i have heard yet ,a store bought composting toilet is $1000-$1500 . THis may work just as well with a small fraction of the cost. YOur final composting does not have to be done in the collection receptacle. WHat about local codes as far as composting human waste on your lot or backyard,i guess its no worse than people with large dogs who dont clean up their back yard very often,probably a grey area.

 

[mesuno]

Yeah, it is quick and cheap to set up :D

We made a base for the toilet seat out of some scrap ply and 2by4. The toilet seat itself was salvaged from an old toilet. The only real expense was to buy 10 matching plastic buckets. You want them all the same size/height and you build the base to exactly fit the bucket. You want a few spares and you need to have 3 or 4 cycling.

We usually have

One in use, in the toilet
One storing clean sawdust beside the toilet (for the "flush")
One full of clean sawdust ready to use.

When the main one is full you just lift it out and put the next bucket (part full of sawdust) in its place. The full bucket of clean sawdust is now your flush bucket. Take the full one out to the garden and empty it - a quick rinse out and it is good to go. Regarding smell etc... the main basic rule is that if it looks or smells bad you cover it with more sawdust. Sawdust itself is free/cheap so you don't need to be stingy with it. Afterall, it all goes to make good compost!

I'm not sure about environmental codes where you are - some regions have utterly daft restrictions which don't take into account the existence of this type of system. I would suggest you use the same basic precautions that would be used if your were planning a new septic tank installation. Think about water courses, runoff, drainage etc... And if you are worried about neighbours complaining keep it out of sight of their garden/fence line.

 

[Seasoned Oak]

Thanks Mesuno for the info
I have a cabin in the woods with no septic system and no plan to spend 10,000 + to put one in for only occasional use. Also Plan to buy a large camper for the lot. Campers use a collection system that must be dumped somewhere periodically,a nasty business in itself ,and if you have it somewhere where there is no place tp dump it you have a problem.
In researching alternatives to conventional septic systems a portable toilet($50 -$150) is also popular but you still have to empty it somewhere,and you still have the smell to deal with while emptying. Im wondering if the sawdust would work in a store bought portable toilet? They generally sell you chemicals to mask the smell,but the saw dust may just eliminate it. I watched a video of the sawdust type toilet used at a music festival with 500 people attending and it worked like a charm and also saved the people thousands in porto potty rentals.probably smell a whole lot better than porta pottys too. If it can work for 500 people it sure can work for a few dozen.

 

[Seasoned Oak]

Yeah, it is quick and cheap to set up :D

We made a base for the toilet seat out of some scrap ply and 2by4. The toilet seat itself was salvaged from an old toilet. The only real expense was to buy 10 matching plastic buckets. You want them all the same size/height and you build the base to exactly fit the bucket. You want a few spares and you need to have 3 or 4 cycling.

We usually have

One in use, in the toilet
One storing clean sawdust beside the toilet (for the "flush")
One full of clean sawdust ready to use.

When the main one is full you just lift it out and put the next bucket (part full of sawdust) in its place. The full bucket of clean sawdust is now your flush bucket. Take the full one out to the garden and empty it - a quick rinse out and it is good to go. Regarding smell etc... the main basic rule is that if it looks or smells bad you cover it with more sawdust. Sawdust itself is free/cheap so you don't need to be stingy with it. Afterall, it all goes to make good compost!

I'm not sure about environmental codes where you are - some regions have utterly daft restrictions which don't take into account the existence of this type of system. I would suggest you use the same basic precautions that would be used if your were planning a new septic tank installation. Think about water courses, runoff, drainage etc... And if you are worried about neighbours complaining keep it out of sight of their garden/fence line.

Mesuno
Is there a time frame to dump the one in use? I only use my cabin infrequently and it could take a year to fill-up. Is there any downside to letting it set for long periods? WIll it begin to smell after a certain time period?

 

[mesuno]

We've had some sit for a few weeks without any ill effect, when we go away on holiday or whatever. I think it would be best just to empty it before you leave though. If it is only part full it won't be heavy or messy to do, and then you come back to a clean toilet afterwards.

 

[kenny chaos]

It seems like it'd be a great way to utilize woodstove ashes also?

 

[mesuno]

Not so good - wood ashed kill the bacteria which break down the humanure, effectively sterilising it. It may be covered but it isn't composting easily. Adding sawdust (high in organic carbon) makes the carbon/nitrogen balance perfect for composting, encouraging the growth of thermophilic bacteria. This guarantees that your waste breaks down really fast and doesn't end up unpleasant or smelly.

Hot composting has the added benefit of killing off any pathogens which might be present in the humanure to begin with.

Mike