Composting Toilet (AirHead) going sour after 5 years

[19523]

Hi all,

My husband and I have been using an AirHead for 5 years now. We actually own two--one (from 2014) on our Ericson 35, and one (from 2016) on our travel trailer. I mention these two dates because there are slight design model changes, but nothing too noticeable. We thought we were AirHead experts, but we've failed to troubleshoot! It is very frustrating.

The 2014 AirHead worked very well when we first got it (learning curve exempt); the compost was healthy, smelled "fresh" like broccoli or peat moss, and vented air wasn't a problem. This was on our first sailboat, an Ericson 29. Despite the 20' vent house traveling through the walls all the way aft, we never had problems with fulltime use.

The 2016 Airhead on our trailer had some problems--the compost tended to be wetter. The hose was about 3', vertically rising into the wall into a cowl. Sometimes the moisture would leak from the handle. We learned we were adding too much hydration; eventually, it composted fine, also fulltime use.

This year, we upgraded to our Ericson 35 and installed the old 2014 AirHead. This time, we added a new cowl vent right by the water intake and holding tank pumpout. The hose is about 5' long, vertical. Early on, we found moisture collecting at the bottom of the hose. We've added a stronger computer fan (Noctua NF-A6x25 FLX) to replace the old one that came with the 2014 AirHead. The bucket's screen, which we replaced with multiple squares of mosquito screens overlaying each other, is clear; I can feel air being sucked in. Fulltime use.

Without fail, every batch of compost is a sludge. The air vented smells terrible, regardless of how dry the coco peat we add is. The fan seems to work great, since every time the peat is stirred, we get a noxious puff of poo-gas.

The first thing I can think of is maybe the pee is backwashing somehow--sometimes toilet paper gets stuck there from the trapdoor, but I routinely scrape out any residuals that could do it.
The second thing I can think of is (TMI) my husband has had watery stools since a bout of antibiotics. He's got an appointment about it coming up. But there seems way too much moisture for that to be it, and that was very recently.
The third thought is, maybe the verticality of the hose is allowing moist air to backwash... yet the 20' ventilation hose had a steep vertical rise before entering the walls and traveling aft on the 29'.

Was hoping someone out there has encountered--and fixed!!--this wall before. Everything should be working from our 5 years of experience, yet it's not!! Very frustrating to experience since we know what it's like to have it working perfectly. My husband is about to replace everything with cat litter instead

--L

[19523]

Updating, I found one review where the users were adding only half as much coir as recommended, and then adding as they went. Eventually they found better results adding after ALL the peat needed (halfway full) at the beginning. We've been getting lazy about waiting till ALL the peat we need is hydrated, and have only been adding half of what we need, then throwing more in later. Will try being more diligent about adding all the peat again at the beginning to see if that makes a difference.

https://www.youtube.com/watch?v=Y9bwrft4L_Q

[Copacabana]

Originally Posted by 19523

Hi all,

My husband and I have been using an AirHead for 5 years now. We actually own two--one (from 2014) on our Ericson 35, and one (from 2016) on our travel trailer. I mention these two dates because there are slight design model changes, but nothing too noticeable. We thought we were AirHead experts, but we've failed to troubleshoot! It is very frustrating.

The 2014 AirHead worked very well when we first got it (learning curve exempt); the compost was healthy, smelled "fresh" like broccoli or peat moss, and vented air wasn't a problem. This was on our first sailboat, an Ericson 29. Despite the 20' vent house traveling through the walls all the way aft, we never had problems with fulltime use.

The 2016 Airhead on our trailer had some problems--the compost tended to be wetter. The hose was about 3', vertically rising into the wall into a cowl. Sometimes the moisture would leak from the handle. We learned we were adding too much hydration; eventually, it composted fine, also fulltime use.

This year, we upgraded to our Ericson 35 and installed the old 2014 AirHead. This time, we added a new cowl vent right by the water intake and holding tank pumpout. The hose is about 5' long, vertical. Early on, we found moisture collecting at the bottom of the hose. We've added a stronger computer fan (Noctua NF-A6x25 FLX) to replace the old one that came with the 2014 AirHead. The bucket's screen, which we replaced with multiple squares of mosquito screens overlaying each other, is clear; I can feel air being sucked in. Fulltime use.

Without fail, every batch of compost is a sludge. The air vented smells terrible, regardless of how dry the coco peat we add is. The fan seems to work great, since every time the peat is stirred, we get a noxious puff of poo-gas.

The first thing I can think of is maybe the pee is backwashing somehow--sometimes toilet paper gets stuck there from the trapdoor, but I routinely scrape out any residuals that could do it.
The second thing I can think of is (TMI) my husband has had watery stools since a bout of antibiotics. He's got an appointment about it coming up. But there seems way too much moisture for that to be it, and that was very recently.
The third thought is, maybe the verticality of the hose is allowing moist air to backwash... yet the 20' ventilation hose had a steep vertical rise before entering the walls and traveling aft on the 29'.

Was hoping someone out there has encountered--and fixed!!--this wall before. Everything should be working from our 5 years of experience, yet it's not!! Very frustrating to experience since we know what it's like to have it working perfectly. My husband is about to replace everything with cat litter instead

--L

If I understand correctly, you fan is pushing air into the composting toilet. It should be sucking air out of the toilet (venting to the outside). If this is the case, you have to flip the fan over so it draws air out of the toilet.

Are you using coconut coir? If so, start with it very dry. If you're using bricks, hydrate it in a bucket, fluff it up and then let it sit in the sun until it's completely dry. It doesn't have to be moist when it goes into the toilet (it will pick up moisture there anyway).

Other than that, perhaps the problem will go away after the antibiotics. If urine is getting into the composting chamber, perhaps adding a little ridge of caulking in the bowl to keep the liquids in the right place might do the trick.

[john61ct]

Yes, drier material or higher medium:stool ratio is needed as BMs get wetter.

The bricks of coir, or fine sawdust will do the job at less bulk compared to peat, fine to experiment with more than one medium.

Assuming the fan and pee issues are taken care of.

[Mike OReilly]

Well, you know it has to be moisture. Either too much is getting in, or there isn’t enough drying going on. This could be due to urine getting in, or nadequate material, or especially liquid bowel movements (although that seems unlikely). If Copacabana’s assessment of your fan is correct, then I definitely concur that it should be drawing out air, not pushing in.

I’m not intimately familiar with Air Head (I have a Nature’s Head). Could there be a cracked gasket or seal that is preventing good ventilation?

[AA3JY]

We use an Airhead that we installed in 2014. We have to say it is a large improvement over the old marine toilet. We did also keep all hoses intact and the toilet is stored away should a new owner (when we decide to sell) prefer the traditional pumping head discharging into a holding tank.
Our Airhead sits up on the platform that held the original toilet. To help ensure urine flows into the urine catchment jug, we have some small wood shims that sit under the rear edge of the Airhead assembly. I have duct taped them down. Maybe your platform tips the toilet back and the urine tends to flow into the compost tank? We found that the level aspect of a composer is important. Good luck.

[19523]

Hi everyone, thanks so much for the suggestions!

Originally Posted by Copacabana

If I understand correctly, you fan is pushing air into the composting toilet. It should be sucking air out of the toilet (venting to the outside). If this is the case, you have to flip the fan over so it draws air out of the toilet.

Are you using coconut coir? If so, start with it very dry. If you're using bricks, hydrate it in a bucket, fluff it up and then let it sit in the sun until it's completely dry. It doesn't have to be moist when it goes into the toilet (it will pick up moisture there anyway).

Other than that, perhaps the problem will go away after the antibiotics. If urine is getting into the composting chamber, perhaps adding a little ridge of caulking in the bowl to keep the liquids in the right place might do the trick.

The fan is blowing the right way--to clarify, I can feel the air being sucked into the bucket through the mesh. It is definitely blowing the air outside, confirmed by being on deck if someone stirs!

Yes, we're using coconut coir. We call it coco peat, but that's technically wrong. We stopped letting it dry in the sun, since the coir* being bone-dry wasn't an issue in the past. I'll do that again to remove that factor.
The caulk is a good idea. I'll test if there is significant backwash.

Originally Posted by Mike OReilly

Well, you know it has to be moisture. Either too much is getting in, or there isn’t enough drying going on. This could be due to urine getting in, or nadequate material, or especially liquid bowel movements (although that seems unlikely). If Copacabana’s assessment of your fan is correct, then I definitely concur that it should be drawing out air, not pushing in.

I’m not intimately familiar with Air Head (I have a Nature’s Head). Could there be a cracked gasket or seal that is preventing good ventilation?

Good point about the gaskets, Mike. The AirHead's seat/lid is removed to reveal the bucket of solids. At the bottom of the seat, as well as an additional lid for the bucket, is a gasket ring. The ring on our seat is actually peeling away in a small section. Maybe I finally can't put it off any longer... I suppose a comparable gasket, or maybe neoprene, and silicone might do the trick?

Originally Posted by AA3JY

We use an Airhead that we installed in 2014. We have to say it is a large improvement over the old marine toilet. We did also keep all hoses intact and the toilet is stored away should a new owner (when we decide to sell) prefer the traditional pumping head discharging into a holding tank.
Our Airhead sits up on the platform that held the original toilet. To help ensure urine flows into the urine catchment jug, we have some small wood shims that sit under the rear edge of the Airhead assembly. I have duct taped them down. Maybe your platform tips the toilet back and the urine tends to flow into the compost tank? We found that the level aspect of a composer is important. Good luck.

We tried a the new freshwater head our 35' came with... and after a week we were ready to return to the AirHead. I'd rather troubleshoot soppy coir than a holding tank any day. We also preserved the original vent freshwater system for when we eventually sell, as well.

We've built a wooden platform to mount the Airhead on, so it's not tilted backwards, afaik. Maybe I will try the wooden shims anyway, if the brackets will allow it.

Originally Posted by john61ct

The bricks of coir, or fine sawdust will do the job at less bulk compared to peat, fine to experiment with more than one medium.

We call it peat, but it is coir we're using. Maybe if all the technical fixes still don't work, we'll bring in the sawdust...

Thanks again, everyone. Will troubleshoot and update in a couple weeks with a new batch...

--L

[captlloyd]

I am still not convinced the fan is plumbed properly. It should not be blowing into the head, it should be drawing from the head.

[Jim Cate]

Not a composter myself (as of yet) but this thread has raised a question in my mind: if the angle of the toilet is so critical that you might need to shim it for correctness, how can you use it at sea with the boat pitching and rolling ?

A potential user wants to know!

Jim

[senormechanico]

Jim,


That's too easy ! Buy a multihull !

[powsmias]

Originally Posted by captlloyd

I am still not convinced the fan is plumbed properly. It should not be blowing into the head, it should be drawing from the head.

nature's head fan blows in

[Uncle Bob]

Originally Posted by powsmias

nature's head fan blows in

Not according to their web site. They state that the unit is designed to pull air in through the toilet and vent it outside.

[powsmias]

Originally Posted by Uncle Bob

Not according to their web site. They state that the unit is designed to pull air in through the toilet and vent it outside.

correct! it is pulling it in but the fan is on the exterior.. so pulling in fresh air to tank

[19523]

Originally Posted by captlloyd

I am still not convinced the fan is plumbed properly. It should not be blowing into the head, it should be drawing from the head.

Unfortunately, the fan is plumbed correctly. I wish it weren't, so that we'd solve this problem easily!

Originally Posted by Jim Cate

Not a composter myself (as of yet) but this thread has raised a question in my mind: if the angle of the toilet is so critical that you might need to shim it for correctness, how can you use it at sea with the boat pitching and rolling ?

A potential user wants to know!

Jim

The trapdoor to the AirHead is already slanted, so it in theory allows liquids to funnel down away from the solids. The extra slant won't hurt, though.

Pardon the stains in the following photos, got it clean as I could! While inspecting and emailing AirHead customer service, there's a caulked/sealed part under the trapdoor to inspect, although ours seems sound. Upon further inspection, there's also a rubber seal railing on either side that is pulling away from the trap door. When the trap door is closed, they push up against against the floor of the bowl when it's right side up. We've siliconed that back, and also adjusted a screw to increase tension on the trapdoor.

Beats a leaky holding tank, I guess

[Nicholson58]

Airhead.


1. We had to stop the ladies from dropping TP in after urination. It always plugged the passage. Hang a bag for the paper and toss contents overboard under way.

2. We found that big sea under way found it’s way into the #2 tank. Never a problem on the Great Lakes but normal in the Caribbean. We disconnect the vent hose from the tank and tie it up very high with a plug installed to trap water. Plug also the vent connection port. We use custom whittled polyethylene foam for the plugs. There is always water in the hose when we anchor.