Toilet Alternatives on a Boat

Hi All!

Partially as a result of very high housing costs, climate crises, and personal inclination, I'm looking to start living on a sailboat in the near future. Naturally, I want to do this in the most permie way possible. However, legal and practical limitations are giving me some trouble.

If you have some sort of acreage, it's relatively simple to set up a composting toilet of some kind. Maybe it's just a bucket with sawdust to cover, maybe it's a willow feeder, maybe it's even a whole septic system with a vermifilter. On a 20-30ft boat, though, you lose a lot of options. A bucket with sawdust might work, but then as they fill you're stacking up bucket after bucket in your very limited space. And even once it's aged and become more-or-less safe, where do you put it? Dumping it overboard is hardly ideal.

There are 'Marine Sanitation Devices' that use a biological aeration/separation process to treat urine and feces, but aside from power use they also rely on chlorine to sanitize the effluent before it can be pumped out. I understand that 'activated sludge' could hardly be tossed into the ocean by itself, but chlorinating it hardly seems like an ideal solution. The main approach that many people seem to use is simply having a blackwater tank that they regularly pump out at the marina, sending it into the larger sewerage treatment system.

Are there any systems or designs which might work well in this specific context?
I was thinking a little of an 'incinerating' toilet, drying out the solid waste and then burning it in a rocket-y stove with good ventilation. Urine could be treated a little more quickly and easily by a compact microbial filter I think, producing a low-nutrient liquid that could safely be discharged overboard.

All your thoughts, objections, assertions and general ideas are very much appreciated!

Hi Lia,
I think you have hit on all the normal methods for dealing with this. Compost, overboard, pumping, and incineration. I think you are going to have to pay for it in some way. With incineration you pay with power, with pumping you pay money. Perhaps you need to pay someone a small fee to dispose of it in their septic tank or use some sort of land-based storage area.

Hi Matt,

You make a good point about potentially paying for the use of a land-based storage area. Though I did try to touch on all the available options, I was hoping someone might know of a particular method or design for implementing these options more well-suited to a boat. For example, a person trying to compost food scraps indoors might not be aware of bokashi composting or vermicompost, which are both 'composting' but have particular advantages/disadvantages that make them better for some circumstances than others, if that makes sense?

Anyway, thank you for your comment!

Lia, see my posts on a related thread here.

Burton, that's exactly the kind of info I was looking for! The Omick site has proved to be incredibly helpful, especially the page about sizing systems and how long things need to age for. Thanks so much for linking that thread!

See also here for more smaller footprint ideas.

Pretty much constantly 80F around here so seweed is composting nicely in a bucket, add poop, cover with a little more seaweed, don't pee in this one.

Odd thing, there's meal worms in there. Surfaced 5 months ago, emptied the bucket but didn't rinse it.

Practically no odor.