Sawdust toilet for small head spaces

[Phantom Jim]

Note: Moving this topic from the "Galley" area to the "Tips and Tricks " area, for sanitary reasons. ;D - CapnK

My son and I are researching the use of the "sawdust toilet" for our respective sailboats, Baba 30 and Pearson 365 ketch.  Before I just start posting details, I wanted to know if there is interest in this topic.  The sawdust toilet is a "composting style" toilet that uses sawdust (as well as many other media) in a bucket.  Complete information at http://humanurehandbook.com/humanure_basics.html.

[ralay]

If you put "C-head" in the sailfar search bar, you'll find one thread on homebuilt composting heads.  There have been more too, though I couldn't find them quite as quickly.

We've been living aboard with an Airhead for 4 years, so I have some experience and ideas on what what would make a good homemade head. 

I think urine separation is key.  If you never plan to have women aboard, maybe you can get by with just a bucket and a bottle.  We've accidentally gotten pee in our poop chamber and the results are bad.  Smelly.  Sloshy.  It's gotta be something people can still poop/puke in when the boat is heeled 30 degrees and it's not safe to do so on deck. 

The airhead has a gasketed lid, some screened vents and a fan that help keep the contents dry and the bugs out.  If you put a regular seat on there, your boat can fill with poop flies.  We get a few even with the gasket, but when we broke the hinges and couldn't keep a seal they got real bad.  We also have a solar fan to pull air from the poop chamber to the outside.  The head gets stinkier in the winter when the solar fan doesn't have enough juice.  I ought to put a 12V fan in for the dark months. 

I don't know if Airheads are really worth $1000 (ours came with the boat), but they have some features beyond being a poop bucket.  It might be a good idea to incorporate those features in DIY heads.

Also, I like coco coir better than sawdust. 

[CharlieJ]

CaptK has lived with a homemade composting potty for a good while.

[Phantom Jim]

I will search for CapK's posts on the subject. 

Our interest is that the AirHead and Nature Head are much too big for his boat, the Baba 30, and would take significant alteration in the head of the 365.  The C-Head is smaller, but still presents an installation problem.

Most small boats have a small head size and a very limited holding tank volume.  Perhaps the smaller sawdust toilet could work effectively as a different option. 

[Bubba the Pirate]

I am super happy with the C-Head composting toilet that I installed; about $400 IIRC

http://www.c-head.com/index.html

[Phantom Jim]

 have searched the archives and find no mention of a "sawdust toilet", or a bucket toilet that contains both liquid and solid human waste.  Please feel free to correct me if i am in error.

The sawdust toilet is a bucket toilet that contains both solid and liquid human waste.  The concept was developed by Joe Jenkins about 30 years ago for use on "back to earth homesteads" using the waste as composted fertilizer.  The premise is simple: a 5 gallon bucket is fitted with some form of toilet seat and damp sawdust medium is used to cover/deodorize/render passive the human waste.  There is no separation of the liquid and solid waste!  About three inches of sawdust is placed into the bottom of the bucket.  After each use, solid or liquid, more sawdust is added to the bucket.  If the toilet stinks or looks wet then more sawdust is added.  When the bucket is about 3/4 full it is placed into a compost pile to compost thoroughly.  When used correctly, the toilet has no foul odors and is easy to empty, especially if the bucket is lined with a sturdy plastic bag.  I would suggest that one read The Humanure Handbook to obtain more information.
(http://humanurehandbook.com/downloadsHumanure_Handbook_all.pdf)

The attractiveness of this toilet to marine use is the small and variable size.   It can be adapted to almost any boat head space.  Like commercial composting toilets, the sawdust toilet uses a carbon based medium, like sawdust, peat moss, coconut coir of wood shavings.  No ventilation is necessary.  It is useful on small boats because coconut coir and equine pine pellets are compressed, easily stored in small air tight containers and expand into usable volumes when dampened.  Boaters are not likely to have composting bins at home and it is perfectly legal to bag and dump the waste into public dumpsters.

My evaluation, over a year long trial, has shown that a 5 gallon contractors bucket is sufficiently large for several days use for two adults.  There is no odor other than the smell of pine sawdust or cedar planer shavings.  I have not used coconut coir.  My purpose for this toilet on our Pearson 365 ketch is to avoid having to travel many miles to a pumpout station on the Texas ICW.  When we get to an anchorage we like, there is no need for us to up anchor to go empty the holding tank.  My son on his Baba 30 is using his as the only marine toilet.  There also in no conflict whether dumping urine overboard is legal or not.  I have also used 3.5 gallon buckets successfully.  We have always been a dinghy ride from a trash dump site.

The sawdust toilet is another option available to boaters, especially small boats.  It is neither better or worse than marine wet toilets or commercial composting toilets.  It is just another choice.

You may contact me via private message if you want more specific information.

[Phantom Jim]

My son, John, and I designed and constructed and tested a sawdust toilet to install in his Baba 30.  This is about as small a head compartment I have experienced in a 30 foot sailboat.  The photo shows the toilet ready for final installation.

[Frank]

A few questions....

Is there a lid on the 5 gallon pale?

Do you put a plastic bag in first before the sawdust?
If so, I assume it folds outward over the top edge.

How is the seat attached? (Picture ?)

How do you mount it to stay in place?

Looks very "neat and tidy"

[Phantom Jim]

Good questions!  The toilet is constructed from two 5 gallon buckets.  One bucket is cut off about 6" from the bottom and becomes the base bucket.  This base is bolted onto the sole or platform where the original toilet was mounted, possibly into the same holes that were used by the toilet base.  I anticipate using a 1/2 inch plywood backing plate inside to give strength to the base bottom.  The toilet bucket slips into the base and is very stable and secure.  There is a plastic catch behind the toilet that is not visible in the picture that keeps the toilet from falling out.

The seat is attached to the toilet using the rim from a snap lid screwed to the bottom of the toilet seat.  An earlier prototype used wooden cleats to make a snap-on connector.  There is no lid on the toilet, but a snap lid should be placed on the toilet before any rough weather to keep the contents from being ejected from the toilet.  Alternately, a seat for a Luggable Loo or a Magellan seat, both designed to snap on a 5 gallon bucket to make a portable toilet would be a very workable option.  The two brands appear to be identical except price.

Unless you plan on burying or composting the waste, I would double bag the bucket with 15 gallon heavy duty kitchen trash bags.  They fold over the rim and the snap lid locks them in place.  It is appropriate and sanitary to dispose of the contents in a public trash disposal can or dumpster as long as the bags are intact.  The contents will be moist, but not dripping wet.

The toilet is managed as per http://humanurehandbook.com/manual.html .  We use horse pine pellets as the sawdust source.  It is cheap, compressed and available at horse and tractor supply places.  Regular sawdust may be too bulky to carry in a small boat.  Coconut coir should work, but I have not tried it.

[Phantom Jim]

More pictures

[Phantom Jim]

More pictures

[Owly055]

     Urine diversion is almost universally considered to be as critical element on any small composting toilet.  These are not considered real composting toilet because they lack the moisture level and time necessary for true composting.
     It's a great topic.   As far as I'm concerned "composting" heads are the only way to go.    I'm interested in any simple refinements people have come up with.   Sawdust is not necessarily the best medium, but does have a nice deodorant effect.

                                                   H.W.

[lance on cloud nine]

I am surprised more folks don't use the new taller more modern, 5 gallon porta potty....and take extra tanks.

[lance on cloud nine]

Meant to first say....Jim - yours looks very well designed/executed. Nice job!

[Phantom Jim]

I agree most boating literature and personal comments consider urine separation to be the holy grail of a composting toilet.  The boat we had to make a toilet for did not have the space available for a separation scheme.  Research into the Humanure sawdust toilet indicated separation was not needed and was actually counterproductive to composting.  The Humanure instructions were followed and both my son and I had very positive experiences, although we used different bucket toilets on different boats with different mediums. 

The commercial composting toilets in reality do not seem to be an actual composter, but a depository for solids until the contents can be composted.  The urine needs to be dumped frequently, perhaps daily.  The difference appears to be that a commercial composting toilet empties the solid tank every several weeks and empties the urine tank daily while the sawdust toilet empties the tank about every three days for a couple.  I have no experience with the commercial products but I do read the posts describing how much the urine jug can smell.  i think the commercial units are good products and better than a holding tank sanitation system.  None would fit the Baba 30.

The toilet for the Baba 30 is a collecting toilet, a different concept than a composting toilet.  If you wish to compost, that option is available.  It could be argued that placing the contents into a dumpster is composting in a way.  I suspect this would be beneficial to the mass deposited into a landfill.  This toilet is a simple device that will fit into the smallest of cruising boats, is ecomonical to build, simple to operate, inexpensive to run and does not smell.  Composting is at the bottom of a list of objectives.  The top objective is no smell!

We have used plain sawdust, pelletized sawdust, red cedar planer shavings, bald cypress planer shavings, pine planer shavings, cross cut paper shreds and peat moss mixed with all the above.  All of the media worked well, but the sawdust was the cleanest and easiest to use.  We gravitate to the pelletized sawdust because it is the easiest compact material to obtain.  It stores in about 1/4 the space that planer shavings and raw sawdust occupy.  It is easy to rehydrate.  It is pretty much dust free.  It smells good.  It is easy to handle.  It costs about $6 per 40 pound bag in the Houston, Texas area.  John plans to store it aboard in the clear 1/2 gallon pretzel canisters.  By our experience and Humanure data, a 40 pound bag will last approximately 30 days for an average size couple.

Once we got the design working, we thought that the smaller cruising boat community might like to hear about our experiences with this marine sanitation system.

[Frank]

Grog to Ya

Seems a really simple an effective option.

When you have time, can you post a pic of how the seat is attached.
Thanks!!

[Steve Bean]

There is a thread here on Sailfar on dry heads. Search for: The $10-20.

[Phantom Jim]

Pictures attached

[Bob J (ex-misfits)]

That is pretty cool.
You can pee over the side of your boat & thats legal but you can't empty a urine collection tank over the side, go figure.

[Phantom Jim]

An interesting article on how and why the sawdust toilet (called a Biolitter Toilet in the article) works.

http://www.eautarcie.org/en/05c.html