Composting Toilets

[Bloodhound]

Originally Posted by sarafina

that is totally helpful Aaron. I had been wondering about liveaboard use, year round when you don't have the suggested *dormant season* to allow it to finish and dump. It sounds as if once a month, or so, you would empty it into the spare composting bucket, if you weren't cruising and had an off shore opportunity to dump. You mention having an airtight lid for the second bucket. Is this ok (none of the ventilation required in the main system to keep the aerobic decomposing) or would the secondary bucket need to be vented once you had it filled and stored to allow it to complete the composting cycle?

Do you collect TP for separate disposal of does it go into the unit?

I would LOVE a picture of your lovely installation with the lid up. I can't really see in the tiny pics on the website how the inside is arranged. A brief, not too graphic explanation of how the wet gets funneled to the forward tank and the solids get sent to the main composting tank would be great.

As far as the emptying of the holding tank for the wet goes, while I know the letter of the law requires that it be treated with the same caution as solid waste, but biologically urine is sterile, does not carry disease and is mostly salt and water. It would not affect the water quality of the most pristine shore if you were to just pour it overboard.

Here are pictures with the AirHead closed, Open and Ready for use. Anatomically we are designed to urinate forward and defecate aft, as it were. The two holes forward are for an obvious purpose. Solids are deposited in a coffee filter placed over the "hatch" and this serves to prevent solids attachment to the toilet unit itself. A handle opens the trap door and the deposit falls into the pit which contains damp peat moss. A turn of the handle mixes the treasure into the batch already in the pit.

Males should probably be cautioned to urinate in the seated position because for many, in a moving sailboat the toilet is a moving target and of course now the target is even smaller, being the two forward holes. Many males don't have the great aim they think they have. Your AirHead should not be used for target practice.

Hope this helps.

Ralph

[blahman]

Ralph,

Good to hear it is working out for you! I think composting toilets are just great.


Sarafina and Gmac,

A couple things to add from our experience.


Cleanliness:

First, we keep a spray bottle of vinegar and water (about 2:1 water to vinegar) and lightly mist the bowl after each use as it prevents any crystalization of urine. A light misting doesn't add anything to the urine tank, either, but keeps the unit smell-free. Also, and more on this in a bit, if you choose not to use filters to "catch" solids, you should have a bristle brush or wipes nearby just in case some of the solid is off target.


Urine/Solid Separation:

As for solid/fluid separation, there is a trap-door that covers the solids tank. This little door acts as a diverter for fluid, so while everyone knows a real sailor sits, it does render most of the toilet's bowl a reasonable target for the standing man. Geoff includes a little photo of the bowl with a few X's over the places that are optimal targets for low-splash, too.

If one is using a coffee filter, solid and liquid can be distributed at any time. If, however, one chooses to fly solo and not use a filter, liquid must be distributed before the trap door is opened. Once, #1 is complete, open the door and commence step #2. I prefer to skip the filter as there were several occasions where I opened the trap door and the filter didn't want to drop, requiring a "push stick". We keep a stick nearby (the same bristle brush mentioned above) for aiding toilet paper (which is sometimes an odd shape). 90% of the time all works out unassisted though.


Second Composting Bucket:

The secondary composting bucket does not need to be vented. In fact, the only reason the Airhead is vented is to keep any smells from settling in the boat. The negative pressure ensures any smell flows out. A fully sealed environment is really best for composting as it ensures enough moisture is retained for proper composting material, and that enough heat can build up. A sealed bucket will compost considerably faster than the vented unit, too. I think something along the lines of fully composted in a month and a half.


Toilet Paper:

We haven't had any trouble with disposing TP used for #2 right in the bowl; it composts just the same, but we use single ply and keep it minimal. I wouldn't want to test using quad ply, lotion impregnated Charmin, even though the bear is pretty cute.

Also, ladies only dispensing #1 are asked to put the TP in a separate trash can as, three or four #1 uses of TP per day by a lady can add a lot of paper to the tank.


Lastly, while this all may sound like a lot of "buts", consider that after the first bit of instruction, it's not tough at all. However, keep in mind that you'll have to explain the Airhead's use to new passengers, and it will be necessary to explain the solid/liquid separation and stuff. Everyone who has been on my boat finds it to be pretty easy and cool.

Just like educating someone on the use of a wet-head.

Cheers!
Aaron

[Bloodhound]

I think the main reason for the air flow through the pit is to ensure aerobic digestion (or composting with oxygen present) of the contents. If you were to transfer the material to a sealed container, digestion would become anaerobic (no oxygen). In aerobic digestion the main product is CO2 whereas with anaerobic systems the main product is methane. The bacteria involved in the two processes are quite different also. I can't imagine why a secondary bin would be necessary --- if you're sufficiently offshore it goes into the sea; if you're in a slip it goes into the garden or into a dumpster (after proper bagging of course ;>)).

I have the muffin fan very close to the through-hull to ensure boat air flows through any leaks into the head and not the other way round. When installing, it's also wise to put a water separator close to the through-hull so that any water that accidentally enters from outside can be diverted into (in my case) the sink drain. I've heard of problems when a boat is heeled sufficiently with water coming in and "backing up" the toilet into the sole. What an unpleasant surprise!

Thanks for the tip Aaron on doing a little spray-down with vinegar after use. Someone also suggested a teaspoon of sugar in the liquid vessel to prevent odors. Does this actually work?

Ralph

[syoder]

Originally Posted by Bloodhound

I Someone also suggested a teaspoon of sugar in the liquid vessel to prevent odors. Does this actually work?

Ralph

Ralph,

We've tried the spoonful of sugar and it works OK but we find that a squirt of dishwashing detergent works better. Not sure if that tip came from Geoff at Airhead or Eric and Sherrell on s/v Sarana. Take a look at their website (FAQs) for lots of practical info. They've been using their AirHead full time for over 4 years now I believe.

-Steve

[ChamJam]

I have a system at my cottage. It works great!!!!!!!!!!!!!!!! I just emptied the compost after 6 months of use. No smell. Good looking fertilizer!!!!!!!!!!!!!
Here is a link in Canada.

Composting Toilets by Envirolet - Sancor Canada

[sarafina]

Originally Posted by Bloodhound

I can't imagine why a secondary bin would be necessary --- if you're sufficiently offshore it goes into the sea; if you're in a slip it goes into the garden or into a dumpster (after proper bagging of course ;>)).
Ralph

My concern is for a situation where you are not offshore and can not dump overboard. You are using the toilet on a daily basis. On the day it fills up there is, er, fresh material in it, virtually uncomposted. I would not feel comfortable putting that material in the garden until it had had time to process. I don't want to have to dump into a bag and dumpster, seems to defeat to some point the point. Hence the idea of a rotating pair of bins, one in the toilet and another that you could transfer into for the more recent material to finish composting.

Is this a reasonable understanding or am I missing something?

and I really appreciate all the feed back and info.

[Bloodhound]

Originally Posted by sarafina

My concern is for a situation where you are not offshore and can not dump overboard. You are using the toilet on a daily basis. On the day it fills up there is, er, fresh material in it, virtually uncomposted. I would not feel comfortable putting that material in the garden until it had had time to process. I don't want to have to dump into a bag and dumpster, seems to defeat to some point the point. Hence the idea of a rotating pair of bins, one in the toilet and another that you could transfer into for the more recent material to finish composting.

Is this a reasonable understanding or am I missing something?

and I really appreciate all the feed back and info.

When you empty the solids bin, yes it will contain some relatively fresh material. If you're living aboard and have access to some burial ground, there's no harm in digging the whole thing into a hole as it will continue to decompose there just as well as in the bin. My father and his 6 brothers and a sister grew up in Western Ontario on vegetables grown in a garden containing last years out-house cleanings. The local farmer driving the plough horse each spring didn't especially like the horse buried to its fetlocks in "stuff", but the cabbages and potatoes were terrific and so was the sauerkraut. Anyway, you need have no concerns about burial of waste. But if you prefer a pair of bins that's okay too, although I doubt 6 weeks is long enough for complete decomposition, and I wouldn't like to keep it sealed either because the bacteria in the batch are aerobic - they require air to work.

[sarafina]

ahh... that would assume dirt and a garden to dig holes in ; -)

we is city folk ya know...

my thought is there is ample shoreline scrub and shrubbery that could be the receptacle of the fully composted goods.

devil is in the details...

[Bloodhound]

Ya can't just toss it into the bloody bushes - it asks to be buried. Alternatively, you could bag it and sell as fertilizer for pot plants. Surely the "odd" live aboard cruiser keeps a pot plant or two aboard. Ought to sell like hot.. aaahhhh... cakes. Especially good for strawberry plants!

[Cheechako]

"If you live aboard and use it every day, math says it won't compost quick enough.."
"As for the urine - that can be a problem..."
"Do you collect TP for separate disposal...."
Hmmmm, think I've heard enough to not be interested!!

[blahman]

"What is that dirty looking water all over the sole?"
"God that smell is terrible!"
"This damn pump is jammed again...wonder if there are any more choker valves..."
"Wonder where I put my elbow-length gloves so I can clean out this locker full of s**t that leaked out of that joint..."
"AARON!!!!!"

I have heard enough to not be interested. Everything has its quirks. The composter's quirks seem like the lesser of many evils.

Cheers,
Aaron

[clausont]

Very interesting thread on the composting toilets. I have always been interested in learning more about them. However, I get the idea that it would not be a good solution for our boat.
Not where we have seven in our family when we go out. Mama, Papa, four girls and one little boy would surely add up to an overload!

[mikeandrebecca]

We have only been boat owners since July but within the period of July 5 to October 23rd, we had multiple problems with our Jabsco head. Although none of our issues were really dramatic (replace joker valve kind of stuff), the simplicity of the composting head is enticing. My wife and I will be living aboard and cruising full time beginning next summer. We are still debating whether switching to the airhead or nature's head toilets will be best for us.

Mike

[Cheechako]

Most head issues are "operator error". In cruising Mexico for 2 years with a Bronze Wilcox head I never had one problem. In cruising the Carribean for 3 years I had one problem with a Jabsco... and yea it was not fun cleaning that out! Flush before using, use minimal paper, flush very well after using, use vinegar now and then.....pump, pump, pump. I have also found that heads with a vented loop on the raw water side tend to be problematic...... seem to suck air in with water rather than a strong flow of water....

[clockwork orange]

cheechako, you must have a lot of holding tank capacity,a lot of smaller boats simply dont have enough capacity for all the water involved .
Steve.