Composting Toilet Liquids Diversion

[Junglebike]

I've been thinking about this for a long time & have run into the same roadblocks. One other is that for my c-head at least, you need to remove the p-tank to get the solids out; this complicates the plumbing a bit. My tank is also below the waterline, so my best idea so far is a pumpout to the sink drain which is above the waterline.

I actually wrote the C-head guy about this and he said he's working on a pumpout system, but it was designed to be pumped after each use, which won't work for the no discharge areas, as silly as that is.

Alternatively I could pump from the tank into a T off my sink drain and out below the waterline and just close the shutoff when not draining.

While I cogitate on this I usually just dump it down the sink drain. It is kinda gross but I agree that it's more psychological than anything else. Maybe better than yet another pump and more below the waterline plumbing.

[jharding]

I hooked mine into my shower sump, I put a cup of water down after I pee. Whats the difference if you pee when in the shower, or pee off the deck, it is sterile. We are a animal in the natural world.

[Disailor]

Urine while not palatable is potable being pathogen free. I pee into a small container then a couple of sprays of biodegradeable non-phosphate soap/water neutralizes the ureic acid & smell & down the sink it goes. I keep a bucket of sea water in the head for a 8oz (+/-) rinse. Quick, clean, sanitary, odor free & climate friendly.

[Mike OReilly]

Originally Posted by Marisita117

Was wondering if anybody has successfully diverted the liquids compartment of the composting toilet overboard via through-hull when appropriate. Really love the idea of this head but with a portable bidet we are afraid the liquids container will fill rather quickly.

As a few have mentioned, it is certainly possible to plumb the liquid flow to an thru-hull, or to a larger holding tank. It's just a plumbing challenge.

That said, I wonder if you still won't accomplish your goal by doing this. The three major commercial composting heads (Natures, Air, C) work by diverting liquids from solids. The seat arrangements match normal human anatomy to allow the two to flow naturally.

A bidet will empty over the solids container, not the urine space. You will be flooding the feces container. This won't work. I think you'd have to build a special bidet for this task.

And just for the record, I've lived with our Nature's Head for over eight years (seasonal use -- say six months at a time). Dumping our urine bucket has never been a particular problem. We tend to dump every 2-3 days for two adults, full time. We carry a spare container, which we have never used, but would allow double that time if need be. It really is a non-issue.

[Junglebike]

Originally Posted by Mike OReilly

As a few have mentioned, it is certainly possible to plumb the liquid flow to an thru-hull, or to a larger holding tank. It's just a plumbing challenge.

That said, I wonder if you still won't accomplish your goal by doing this. The three major commercial composting heads (Natures, Air, C) work by diverting liquids from solids. The seat arrangements match normal human anatomy to allow the two to flow naturally.

A bidet will empty over the solids container, not the urine space. You will be flooding the feces container. This won't work. I think you'd have to build a special bidet for this task.

And just for the record, I've lived with our Nature's Head for over eight years (seasonal use -- say six months at a time). Dumping our urine bucket has never been a particular problem. We tend to dump every 2-3 days for two adults, full time. We carry a spare container, which we have never used, but would allow double that time if need be. It really is a non-issue.

The bidet is a separate issue; I agree, you can't have liquids getting into the solids! I have 3 daughters, and my wife and I drink lots of great San Diego beer. I'd rather not have to dump the tank into the sink 1-2x per day, but only if it doesn't complicate things too much.

I like the shower sump idea - mine isn't working properly right now but it'd be pretty easy to fix it up and plumb into that line. I'll take a closer look - thanks!

[alansmith]

NormL 24 hour urine volume is between 1000-2000 cc/day. A gallon = approx 3700 cc. So a gallon jug will need to be dumped daily. No beer guzzlers allowed on my watch.

[valhalla360]

We filled our natures head about every other day...then we would dump it.

We did hear of a few who simply left the waste tank in and plumbed a small pump to that. With just liquid, it largely eliminated the clogs and smell associated with the waste tank...then that tank could be emptied via gravity or at a pump out as needed...but with longer duration between the need.

We preferred getting that big space back for storage, so the tank went away.

[Chotu]

I'm looking at teeing it into a thru hull with a valve to shut it off for potty (pee?) police issues.

My c-head issues are numerous because my girlfriend is first generation born in the USA Desi. She uses the rinse/bidet method before the toilet paper to dry. Hey, at least she's really clean! Ha ha.

We had a temporary c-head in the monohull this summer. She used baby wipes (which is what I do) but doesn't want to make that sacrifice on the boat built for us.

So I have to deal with bidet water as well as urine in the diverter. I'm hoping this will be fine. I just have to have a bit larger urine divirter. I have to give her credit for being willing to use the thing in the first place. It's a LOT easier for a guy to use.

So the plan is a gravity line from the diverter to the above the waterline sink drain. This means a step up to the toilet seat, but well worth it in place of lots of plumbing. Shut off valve for potty police.

[valhalla360]

One potential problem with a bidet system and a compositing toilet, is the whole idea is to separate water from solids.

I would be worried that if you are rinsing...solid remains...do they make it thru the liquid diversion system and while they are sitting, do they emit odor into the head. The seal on the urine container isn't that good because it doesn't need to be.

You certainly don't want to be sending a few cups of water into the solids container each time you have a #2.

[Marisita117]

I read on the airhead and nature's head that there is no "aiming". The only way liquids go into the solids compartment is if the "trap door" is open. Correct me if I am wrong though!

[valhalla360]

Originally Posted by Marisita117

I read on the airhead and nature's head that there is no "aiming". The only way liquids go into the solids compartment is if the "trap door" is open. Correct me if I am wrong though!

Unless you aren't feeling well (and both sides are coming out liquid)...generally, liquids come out the front and solids come out the rear. The toilet takes advantage of that to not let them mix as the primary separation. A little overspray hits the trap door, no big deal, most will go into the liquids container with just a few drips into the solid container.

But if you spray water significant amounts at the rear, you increase those drips into the solids container (too much water and you are no longer composting) or as it washes stray solids off your rear, do the solids get washed into the liquid path and clog the liquid side of the system.

If you ask me to draw a picture, you are on your own.

[Chotu]

Originally Posted by valhalla360

One potential problem with a bidet system and a compositing toilet, is the whole idea is to separate water from solids.

I would be worried that if you are rinsing...solid remains...do they make it thru the liquid diversion system and while they are sitting, do they emit odor into the head. The seal on the urine container isn't that good because it doesn't need to be.

You certainly don't want to be sending a few cups of water into the solids container each time you have a #2.

If that's addressed to my post, you just have to increase the size of the urine catchment area. Think not perfectly oval toilet seat like a home toilet seat, but one of those public toilet seats that's open in the front. Make the front 1/2 of this thing the urine catchment and the back half for solids. Then you can rinse off in the front half of it, which drains overboard via gravity via the sink plumbing.

We keep a vinegar mix spray bottle nearby to rinse that urine catchment area each time it's used.

[valhalla360]

Originally Posted by Chotu

If that's addressed to my post, you just have to increase the size of the urine catchment area. Think not perfectly oval toilet seat like a home toilet seat, but one of those public toilet seats that's open in the front. Make the front 1/2 of this thing the urine catchment and the back half for solids. Then you can rinse off in the front half of it, which drains overboard via gravity via the sink plumbing.

We keep a vinegar mix spray bottle nearby to rinse that urine catchment area each time it's used.

No, it was a general response to the bidet idea. If you are doing a home build, you might be able to do something else but it sounds complicated.

But from experience with natures head, I would be concerned if any larger chunks get washed into the liquid path and if you open the trap door for #2, there is nothing to stop the bidet water getting in with the solids.

[Mike OReilly]

Originally Posted by Junglebike

The bidet is a separate issue; I agree, you can't have liquids getting into the solids! I have 3 daughters, and my wife and I drink lots of great San Diego beer. I'd rather not have to dump the tank into the sink 1-2x per day, but only if it doesn't complicate things too much.

I like the shower sump idea - mine isn't working properly right now but it'd be pretty easy to fix it up and plumb into that line. I'll take a closer look - thanks!

I think the shower sump would work, as long as you can keep it clean over time. Human urine will start to smell, and if you think of the odour from a urinal, even one that is constantly cleaned, well... I'd be cautious about using the shower on a continual basis for this. Might be OK, but...

The other thing to note is that the commercial versions of these heads (Nature's, Air, C) are all aimed at small crew compliments: two, perhaps three adults full time. You can get away with higher numbers for short periods, and if you're only using the boat occasionally you can also add more people. But I fear you may have poor results with five people on board if you are using the head for more than a few days at a time.

Originally Posted by Marisita117

I read on the airhead and nature's head that there is no "aiming". The only way liquids go into the solids compartment is if the "trap door" is open. Correct me if I am wrong though!

You're correct in that the design of these heads direct the flows appropriately. But while there is a trap door over the feces container, it is not a water-tight seal. Any liquid that spills into the catchments zone will eventually drain into the feces container.

A little liquid is OK, but not bidet amounts.

[NorthCoastJoe]

Maybe you need a second catchment device for the bidet. Can not see any other way that would work. I have an Air Head and the pee bottle is no big deal.
Most of the time for guys pee in the sink, and a few hits on the pump of fresh water never had a smell problem.

I removed the traditional head because of smell, I am very happy to have done this on two boats now.