Sawdust toilet for small head spaces

[Frank]

Thanks for the seat pictures.
I like anything that is simple and works....inexpensive is a bonus too.
This certainly qualifies on all counts.

Have another grog 😀

[Phantom Jim]

Thank all of you for the compliments.  We wanted a toilet to replace the existing marine toilet but would not change/alter anything in the head compartment.  This design lets us replace the old toilet when resale time comes and there will be no damage or obvious alterations.  That is why the toilet seat has the attachment wings still there.  I think that a composting toilet, especially a home made one regardless how good it looks, would only detract from the value.  Many are not as enlightened as you.

This is one of many viable toilet options on boats, of which most are good.  It may be attractive to some and not to others.  This toilet has a dumping schedule very similar to when we need to dump trash, so a separate trip ashore is not necessary and pump outs are totally avoided.   It also avoids the smelly wet marine toilets we had suffered with and all the repairs/rebuilds and it is so much easier to clean around the base.  It also cannot really break down and leave you without a functioning toilet.

The next experiment is to get the coconut coir bricks and determine whether it will store in a more compact manner than the pelletized sawdust.

[Bob J (ex-misfits)]

The next experiment is to get the coconut coir bricks and determine whether it will store in a more compact manner than the pelletized sawdust.

coconut coir bricks might store easier on the boat but you're using the same collection bucket for #1 & #2. The  bricks may not have the absorption properties as sawdust.

[CapnK]

Hi Jim - where do you source the pelletized sawdust?

[Phantom Jim]

Compressed pine pellets are available at TSC Tractor Supply, Co. located in all Gulf Coast states as well as the eastern seaboard states for about $6 per 40 pound bag.  The pellets are also available at Walmart and pet stores as wood pellet cat litter, costing a lot more.  Horse equipment and supply stores will sell the pellets as well and the cost should be similar to TSC.  They are available online but I have not needed that service.

I have only tried the pine pellets but there are internet reports that hardwood pellets used for heating furnaces are better.  We do not usually heat our homes with this type of furnace in Texas and I do not have ready access to these pellets.

I have located coconut coir bricks at local pet stores as a medium for reptile terrariums.  I will try this soon, but my suspicion is that this will be dusty.  It is a renewable source and very water absorbent and deserves a good look.

As a comment on the organic media I have used, I found advantages and disadvantages with all of them.  Peat moss is a non-renewable source I would prefer not to use and it was exceedingly dusty.  It left a fine layer of brown dust everywhere.  Paper shreds took an enormous volume to work the toilet.  I think it is the mass of the medium, not the bulk that is necessary and paper shreds are not dense.  Paper shred got everywhere as well.  Wood planer shavings and shop sawdust worked well but were dusty, not as dusty as peat, but it was noticeable.  They all smelled good.  I found that a five gallons of "foot" compacted shavings provided medium for two toilet cycles (5 gallons of pellets was 5-6 cycles).

Since our cruising is typically local and for 10"ish" days or so, we will probably use planer shaving until that source is gone.  Our Pearson 365 is big enough to hold 3 or 4 five gallon buckets of planer shavings, enough for 9 to 12 days.  We do not exclusively use a sawdust toilet, only when we are inconvenienced by needing a pump out.  If our current PHII toilet fails, we may convert completely to a sawdust toilet.

John, on his Baba 30, needs a more compact medium when he cruises.  His only toilet will be a sawdust toilet and he simply does not have the storage space for 6 or 7 five gallon buckets of a semi-compacted medium.  He can store 10 to 20 1/2 gallon jugs of pellets easily.

I hope this helps.

[Owly055]

Another possible material for the job might be alfalfa pellets sold for livestock or pet feed.  They can often be bought in bulk or bagged.

I've been reading various articles on composting.  With proper moisture content and oxygen composting happens quite rapidly.   The temperature is important.   The bacteria will generate heat which should be contained.   The carbon / nitrogen ratio is important.    With all the factors in balance, composting times can be reduced to a couple of weeks rather than months.   The thermophilic bacteria that are responsible elevate the temps enough that pathogens are killed.   Temps as low as 130 over an extended period of time (several weeks) are enough to do the job.    The typical marine "composting head" doesn't compost at all, it merely dehydrates.

                                           H.W.

[Bob J (ex-misfits)]

Wood shavings should be available at a feed store also.
We used them at the farm for poultry & piglet bedding
I purchased a boondock c head over the winter & that is one of the mediums they recommend.

[Phantom Jim]

Wood shaving are prominently mentioned in web discussions as a good medium for a composting toilet, but a quick review of the web does not reveal any mention of alfalfa as a medium.  There is no reason it would not work.  As stated before, I look for compact or compressed media for use aboard simply to lessen the storage volume needed. 

As a reminder, my sawdust toilet design is not a composting toilet but a collecting toilet.  If you wanted to take the contents home and compost it, that becomes composting.  I do not anticipate composting the toilet contents from our boat.  I would prefer our operation to be environmentally friendly though.

I would not expect this design to be appropriate for boats venturing out for months at a time unless there was a provision to obtain the media, either by purchase or by foraging.  I see it being useful in cruising where the boat is out for 1 to 3 week cruises or in areas where one could reasonably obtain additional media as needed.

[Owly055]

Wood shaving are prominently mentioned in web discussions as a good medium for a composting toilet, but a quick review of the web does not reveal any mention of alfalfa as a medium.  There is no reason it would not work.  As stated before, I look for compact or compressed media for use aboard simply to lessen the storage volume needed. 

As a reminder, my sawdust toilet design is not a composting toilet but a collecting toilet.  If you wanted to take the contents home and compost it, that becomes composting.  I do not anticipate composting the toilet contents from our boat.  I would prefer our operation to be environmentally friendly though.

I would not expect this design to be appropriate for boats venturing out for months at a time unless there was a provision to obtain the media, either by purchase or by foraging.  I see it being useful in cruising where the boat is out for 1 to 3 week cruises or in areas where one could reasonably obtain additional media as needed.

     At sea on extended cruises, the "direct deposit" method is probably the most practical.............. Or the "bucket head" with the contents immediately going over the side...... assuming you aren't in the ICW or some other confined area.   How many millions of fish, dolphins, whales, etc are crapping in the sea every day??   It's not "pollution" in the open ocean, it's food for various organisms in the oceanic food chain.  It's only pollution in confined areas, harbors, rivers, etc.     I suggested the Alfalfa pellets because they are dense and heavy, and expand greatly....... and cheap.

                                           H.W.

[Phantom Jim]

The sawdust toilet is not ideal for offshore work where overboard discharge is legal.  I have found that the 3.5 gallon bucket at Lowes will slip inside the bowl of my Raritan PHII and be somewhat secure.  I have used this with a Magellan snap on lid as the toilet.  If I were a serious offshore sailor I would want a direct overboard discharge toilet.

USCG regulations state that where a portable toilet is installed, a direct overboard discharge toilet must be disconnected from the through hull fitting.  If a cruiser arrives in US waters with a direct overboard discharge toilet, they could disconnect this toilet and use the 3.5 gallon sawdust toilet during their stay in US waters.  This seems to be an inexpensive and non-invasive way to get decent sanitation in these boats.

Of course you would have to get used to the bright pink color ;)

It just goes to the concept that there is "no one size fits all"!

[Phantom Jim]

I have looked again but I find very little about alfalfa except as an animal food.  Since i have enough medium for a couple of years cruising, I probably will not go beyond testing a single coconut coir brick.    Someone test it and report back. 

Alfalfa is a food and sawdust and coir are byproducts, perhaps we should use the byproducts rather than the food.  Any thoughts?

[Owly055]

Alfalfa is a food and sawdust and coir are byproducts, perhaps we should use the byproducts rather than the food.  Any thoughts?

     I personally would not be bothered by this......... nothing is going to starve as a result.  Nearly every organic material is food for something.    I find corn based ethanol far more disturbing.  Not only is a food product being wasted, and farmland being diverted to an inapproprate use, but the petroleum energy going into production exceeds the output......... Also do you experience guilt every time you drink a beer or whiskey, knowing that a "food" product is being wasted for your drinking pleasure?  \
     To me it's a complete non-issue........

                                                             H.W.

[Owly055]

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.

Jim Brown, designer of the Searunner series talks about simply having an opening in the wing of a trimaran as a sit down toilet......."Gentlemen Please Be Seated"....... In rough weather, it could even be a toilet bidet combination   ;-)

                                                                 H.W.

[CharlieJ]

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.

Jim Brown, designer of the Searunner series talks about simply having an opening in the wing of a trimaran as a sit down toilet......."Gentlemen Please Be Seated"....... In rough weather, it could even be a toilet bidet combination   ;-)

                                                                 H.W.

The 60 foot tri Rogue Wave had that set up

Offshore, you can legally dump a Porta Potty overboard. East coast of US must be over 3 miles out. West coast of Florida requires 9 miles

[Phantom Jim]

I have started evaluating coconut coir.  I purchased a three pack of bricks form Petco for $10.  Each brick is expected to  expand to 7L (8 quarts) of medium.The following is a comparison of pine pellets to coconut coir.

Pine pellets: $0.60 per cycle   coir: $5 per cycle
Pine pellets:  2 lbs/cycle        coir: 1.5 lbs/cycle
Pine pellets:  216 cu.in.         coir: 122 cu.in.
Pine pellets:  odor pine          coir: odor musty earth
Pine pellets: color tan/yellow  coir: dark brown

So far pine pellets are less expensive by far, but are marginally heavier and have about twice the volume.  The odor, in my opinion, certainly is in pine pellets favor.

My opinion, at this time, is that a less costly source of coir is needed to make it a viable medium.  The space and weight differences are not great enough to warrant the extra cost.

Stay tuned for the next episode.
   

[Phantom Jim]

My findings and my opinion. 

Reconstituted coconut coir is a fine, fibrous, mulch-type of material that has a neutral odor.  It is dark brown in color which is an advantage when looking into the toilet.  A three pack of 650g bricks will make about 6 gallons of medium at a cost of around 10 dollars.

One cubic foot of coir, 8 three brick packs, will make 48 gallons of usable medium at a cost of approximately $80.   This will be about 14 cycles with a cost per cycle of about $5.  One cubic foot of pine pellets, a 40 pound bag, will make 32 gallons of usable medium at a cost of $6.  This will be 9 cycles at a cost of $0.67.

Coir will have 50% more cycles per cubic foot but will cost 120 times more than pine pellets.

Reconstituted coconut coir appears to be more difficult to reconstitute for use than pine pellets, needing about 12 or so hours to get to a point where it can be hand fluffed into usable medium.  Pine pellets require a little water and about 1 hour and a good shaking in a partially filled jar.

My opinion is that coir is definitely a good medium to use, but the cost is at least 120 times that of pelletized sawdust. 

Note: for those going out for a week, a 2 cu. ft. bag of fine mulch will give 4 cycles of the toilet with out breaking the bank or filling the boat with an enormous amount of medium.

[Phantom Jim]

Coir will have 50% more cycles per cubic foot but will cost 120 times more than pine pellets.

My math was fuzzy, I must have been paying attention to Congressional accounting.

Pine pellets will cost about $6.70 per month.  Coir will cost about $50 per month.  Therefore coir is 7.5 times more costly than pine pellets.

Sorry

[Phantom Jim]

We installed the sawdust toilet in the Baba 30 this weekend.  It is a clean, functional install that is sturdy.  The head in the Baba 30 is about the smallest head I have encountered but the toilet fit well.

[Owly055]

Most folks mow lawns......... How about dried grass clippings?  Or forest "tuff".... the dried layer shed needles under pine and fir trees?   Do we really need to actually buy material for these toilets?

                                                     H.W.

[ralay]

You can buy compressed coconut coir a lot cheaper on Amazon.  It's more like $1.70/compressed lb or $1/rehydrayed gallon.  If you estimated you need 1.5 lbs per cycle, that's more like $2.55/cycle.  I didn't bother to look for the best deal on Amazon either, I'm just looking at the first 10lb blocks that came up. 

Also, in practice, with a dessicating style head, we empty it at most 3-4 times per year living aboard.  A single bag lasts a year or more for roughly $15.  There's no way we'd pay $50/mo for toilet fluff. 

We don't bother to reconstitute the coir at all.  We just break off chunks and throw it in the head.  It reconstitutes itself in its own time with whatever moisture is in the waste.  It's really compact to store the bricks.

I guess if you don't want to separate liquids you will go through a lot more media.  Maybe at that point the difference between $2.50 for coir and $.60 for pine is significant.

For us, the $10/year is such a small part of our boating expenses that we just buy the stuff we think works best.  I don't exactly have a lawn or anywhere to dry and store a bunch of  someone else's lawn clippings.