[RainDog]

After many attempts to get our head to not stink, we finally decided it was not going to happen and opted for a composting head. None of the commercial models seemed to fit in the 34 head space, so we built our own. Details on our blog: Head Project | Rain Dog. So far so good.

 

[oceangirl]

 

[svjobeth]

Interesting - and congrats!

As a part of our refit, we're replacing the ancient Groco KH head with same, as well as replacing all of the plumbing and the Y-valve. Key though, is we're also replacing the existing and original wooden holding tank lid with fiberglass. That, plus regular use of a holding tank 'deodorizer' will keep any odor issues to a minimum. We hope.

We've also found the Groco KH to be a near bullet-proof head. It should be for the price! (After 20+ years of nearly failure-free service, and countless rebuilds, I'd say it's worth every cent!) The massive piston pump evacuates things remarkably well, which of course helps with stinkiness, though it also moves an impressive volume of water, and over enthusiastic flushing will fill a 34's holding tank quickly. One thing some friends of ours have done on their boat to help with odors is to only use measured amounts of potable fresh water for flushing the head. Often, what's mistaken for human waste odor is actually the accumulating decay within the hoses of all the stuff in seawater, (Or, fresh water if you're a laker...), which can build up on the walls of hoses.

 

[Brent Swain]

The fan on my composter quit so I have been sprinkling a bit of dry swimming pool bleach in from time to time. Works well. No smell.

 

[miatapaul]

Do you have a method to stir it or do you simply put a scoop on top of your deposits?

Thinking of that I read a funny mime the other day:

He who stirs the s*** pot should lick the spoon....

 

[BMLipiec]

Nice job guys! Looks great. It's always funny to see the reaction we get from people in our marina about our composting head. They act as if we have lost our minds. Our neighbor has had to replace his macerator 3 times and the hoses once in the past year - horrible job. He still can't be convinced that the composter is the way to go.
We've only used it for weekends and week long trips so far, but we are really happy with it - zero problems or smell. We are glad we took the plunge.

 

[oceangirl]

Brent, great idea about the bleach. I have poo powder but have yet to use it. So far this desiccating head thing has kinda taken care of itself.

Miatapaul,
We do not have an agitator per say. I bought an extra long handled ss serving spoon. I've used it once to see what all was going on in there and it just looks like dirt. I store the spoon in a sealed container behind the head.

We have a mini dehumidifier running in the head 24/7. I also have been using the wag bags I had leftover from the experimental phase to line the poo bin. The wag bag has a little poo powder in the bottom, this may be why moisture is not a problem and our desiccating head works so well.(?)

I added a Q&A to our head page on our blog, will keep adding as questions as they come in. Sorry if it is a little jumbled.

 

[miatapaul]

Brent, great idea about the bleach. I have poo powder but have yet to use it. So far this desiccating head thing has kinda taken care of itself.

Miatapaul,
We do not have an agitator per say. I bought an extra long handled ss serving spoon. I've used it once to see what all was going on in there and it just looks like dirt. I store the spoon in a sealed container behind the head.

We have a mini dehumidifier running in the head 24/7. I also have been using the wag bags I had leftover from the experimental phase to line the poo bin. The wag bag has a little poo powder in the bottom, this may be why moisture is not a problem and our desiccating head works so well.(?)

I added a Q&A to our head page on our blog, will keep adding as questions as they come in. Sorry if it is a little jumbled.

Glad it is working out for you, but I have made a mental note, be sure to check what spoon oceangirl uses if I ever happen to be at a pot luck where you guys are bringing the chili! :laugher

I am a fan at least in theory of composing heads, and I like yours as it is affordable and would make a good test. The last boat I looked at had a small head, and I was thinking that none of the commercially available ones would fit. I am impressed with your willingness to experiment! I don't think anyone in my family would be so open to options. Perhaps OK with a commercial version, but homemade might scare them off. Of course the painted design on the front helps make it look a bit more finished.

 

[oceangirl]

Miatapaul, after rebuilding a couple heads, replacing a couple more, replacing all hoses a few times, and replacing a 30 year old holding tank, a gal just gets gets desensitized to the uglier side of living aboard. Oh how I would love to go back to the blissful days of direct discharge, no odors, little maintenance, easy peasy.

The new 2.5 gal container is stinking, never had that issue with the one gallons so we are back to one gallons and a fresh smelling head

 

[SimonV]

I am a Bit lost here. Is it a composting toilet or is it just a bucket? I always thought composting took months and you where required to stop adding fresh mater to allow complete composting. By adding bleach would you not kill the good stuff to help composting.

 

[oceangirl]

Yes, it's just a bucket. Just like the holding tank is just a box for pee and poo

~~My husband explained it best just the other day. This is a cut and paste from that post.

“It (desiccating heads) does not really compost. Urine separating heads are actually desiccators, not compostors. It is actually almost the opposite. Composting is all about building up a large colony of aerobic bacteria (it is only the anaerobic that stinks as I understand it) to prevent odor. Desiccators are all about preventing any bacteria colony from forming by preventing any moisture. The bacteria needs moisture to survive. This is done by

1) Separating the urine from the feces

2) putting moisture absorbing materials in with the feces

3) mixing to make sure the moisture absorbing material can absorb all the moisture

4) ventilating to keep a good exchange of air in order to prevent moisture build up in the container.

All of this is supposed to keep anaerobic bacteria colonies from forming, thus preventing odor. You do not need heat, but ventilation helps. As far as I can tell, all urine separating toilets do #1 and #2 above. All commercial models also do #3. Not all, but some, do #4. We currently do #1, #2, and #3. #4 we will add if we need to, but not until then.”

 

[Minnewaska]

Composting heads only partially compost at best. Your last "deposit" is certainly not composted at all. Ventilation is important, as oceangirl's husband correctly identifies the difference between aerobic (needs air) and anaerobic (can't live in air) bacteria.

Anaerobic bacteria are the ones that stink. However, they are the ones that are in your gut too, so you can't fully keep them out. You have to have a good aerobic environment, so they die quickly and are replaced by aerobic bacteria, if you're trying to decompose your waste. This principal is the same in a composter or a holding tank. The biggest problem with holding tanks is that boaters do things that kill aerobic bacteria all the time. Such as, flushing oil, which skims the top of the water and prevents air exchange, or flush chemical cleaners, or don't flush enough clean chase water so waste sits in the unventilated hose, or simply don't have sufficient tank ventilation to begin with. The single biggest mistake is....... flushing chemical deodorants!! They just kill the good bacteria, so once they wear off, the tank is even worse!

A small 12v ventilation fan for a composter makes all the sense in the world to me. Besides the negative pressure, that would draw any odor (even the earthy soil odor from most) to the outside, the fresh air being introduced would create the best composting environment. I suspect, while oceangirl is dehumifying, the real benefit is the constant exchange of fresh air.

 

[Brent Swain]

Do you have a method to stir it or do you simply put a scoop on top of your deposits?

Thinking of that I read a funny mime the other day:

He who stirs the s*** pot should lick the spoon....

Yes, I have a handle built in to stir it (S***t disturber) but if it lands on the solids and reacts with moisture, it releases chlorine, which kills the bacteria anyway.