Composting Toilets

[Island Time 1,235]

Composting toilets are making inroads into the marine market. There are two main brands, Natures Head and Airhead. They have several attractive advantages over a traditional marine head;

 

1/ Cost - retail is about $1400 NZD, so way less than a traditional head/holding tank/treatment system

2/Simplicity - no pumps, through hulls, hoses

3/Environmentally friendly - no discharge at all

4/No smell - when operated correctly they don't smell at all!

5/NO power consumption (when fitted with solar ventilator).

6/No blockages

7/Virtually maint free

 

The disadvantages are

 

1/ They must be emptied - both the common units hold about 80 "deposits". The waste inside should be dry, and have a slight "earthy" smell. It is NOT safe to put on a vegetable garden, but can be dumped in the waste, overboard if offshore, or spread on a flower garden or similar. Say once a season for the weekender, or once a month for a live-aboard with 2 people.

2/ Size - they are bigger than a conventional marine toilet bowl about 56cm tall, 42 cm wide, 47 cm long

 

I can get the NZ agency for Airhead, and would be prepared to offer a substantial discount to the first orders - I have to by 16 at a time (a pallet).

 

Would anyone be interested?

 

Cheers

Matt

[Adrianp 120]

Don't the major systems separate the pee into its own container which needs to be emptied frequently? The promo stuff seems to gloss over that fact.

[Island Time 1,235]

Yes, that is part of the design requirements to make them odor free (when used properly). Urine is no issue to tip overboard - it's sterile... Its the fecal matter that is the issue for discharge.

 

In the reports of use I have read, both good and bad, no-one complains about the emptying of the urine tank. If you find the urine tank smells, put in a teaspoon of raw sugar, that will apparently fix it.

 

Some cannot stand even the idea of emptying the solid waste - if that's you then it's not for you.

There have been reports of smells - mostly due to incorrect operation - not moistening the coir base, or making it too wet. Read the instructions!!!

 

The other has been infestation of insects, especially in areas with very small flies. Put a "no see-um" mesh over the air breather so insects cannot get in, and make sure your coir has no eggs or larvae. A single coir brick from the local plant depot is sterile, compressed, and will last for 12 or more refills.

 

That is all my current understanding after a bit of research.

 

Oh yes, one more plus - the composting heads are lighter than a conventional head and holding tank....

[Rangi1 51]

Not for me - for one, I'd never get my wife on it but it also seems like one additional hassle I could do without (guess who would be emptying it!).

 

We've gone down the electroscan way - not without its problems or cost, but overall I'm happy with it. My boat's a cruiser so I don't spend a lot of time worrying about the additional weight or even power draw. we tend to spark up the engine when the unit's running.

[Steve Pope 243]

Yup, I would be interested, will pm you re further info

[Island Time 1,235]

Rangi, I had a lectrasan. 4 new electrode sets (about $700 each) and 2 circuit boards (also 100's) later (14 years) I've biffed it. Too much $ and too much maintenance long term. AND, eventually it will smell...

 

This system is way more simple. Simple is good!!

[wheels 543]

So is there a Hole in the bottom of the bowl that allows a view of all the Goods? or is there some kind of a flap that opens and closes so it all remains discrete?

So I can understand after it has composted for a couple of days, that there would be no smell when you go to empty it. But what about the days...errr....pile. Or do you put that aside and empty the composted stuff and then...nah that sounds all too messy. So do you just put up with one or two "steamers"?

Now here's another good question. So what about someone seasick and rushes to the loo to throw up in the loo? Can it deal with that kind of thing? or do you need some rules of what can and can't go in?

And a final one, how much room under the Loo does it need, or is there like a Cassette and the whole thing sits on the floor, rather than something under the floor level.

[Island Time 1,235]

Ok, yes there is a flap. The waste is mixed into the coir is the base with the "flushing" lever after each use. "Composting" is a bit of a misnomer - it takes over 2 years for human waste to fully compost. This is more of a drying unit - there is airflow, via a pc type fan or a solar ventilator.

The unit is a "cassette" type. The whole unit is a little smaller than a domestic toilet, and sits on the floor.

A vomit or two would be better over the side, but should not effect the unit unless there is a LOT of volume. Same if you get the runs...

Full details are available at http://www.airheadtoilet.com/

or ask anything you like here.

[Black Panther 1,591]

What are the dimensions? A bit early for me but if I am rich and you need one more to get over the line call me.

[Island Time 1,235]

Dimensions;



Install Video

[Black Panther 1,591]

I am on the boat now and just measured it. Easy fit. So if you need one more maybe. But definitely if you do a second order

[Island Time 1,235]

Update on this - I have bought in a shipment. There are 5 remaining. Depending on the time it takes to sell them, I may order more. Unit cost is $1375 + GST. 

First impressions are;

It looks smaller than I expected. 

Insect screens for the air ducts are included.

Everything you need is in the box except for the coconut coir.

 

The Airhead has a seat seal, so you can use it in a toilet/shower area. Some of the others can't do this, as a shower will allow water to enter the unit!

 

 

I'll do some pics of my install over the next week. Anyone want to by a Lavac Zenith marine toilet, complete and in good working order? Open to offers!!

[Battgirl 23]

Great IT i am going to order one from Neptune now. Cheers

[Romany 162]

Very funny. Aria Motion Pictures....

 

Matt - what is the cost for new shitter of the airhead variety?

[Romany 162]

sorry - just read your other post. A serious deposit needs to be made for now so I 'm out (I mean before I can afford it. Not that I need to go potty)

[Island Time 1,235]

No worries. If anyone wants one, probably best to just send me an email. matt@neptunes-gear.com Seems I have a bug in the website that is not adding GST onto these for NZ deliveries. I'm working on that! If you let me know you want one and I will send you a proper Invoice, incl payment details.

Cheers

Matt

[Island Time 1,235]

Here is a brief rundown of installation on Island Time. 

Here's a pic of the original Lavac install in the aft head compartment;

 

So, I removed this toilet, the henderson mk v pump and all associated hoses, the lectrasan, all its cables etc. I removed the 90 deg hose tail from the seacock, and installed a plug. Provided I'm happy with this setup (and I expect to be), in due course the sea-cock and thru hull will be removed as well - of course when out of the water! All that was harder than installing the Airhead!!

 

I ended up with an empty space, but on test fitting the Airhead, I decided to remove a bit of the liner behind where the airhead will go. This is to get the unit as far back out of the way as I can. Make sure all doors, cupboards etc can open with your intended install position, and that you can turn the crank/"flush" leaver!! Here are the results;

 

The hole in the liner is not an issue for water from the shower, it all drains into the sump liner, which goes up the side of the hull further than this.

 

So now I fitted the base mounts for the Airhead, they simply screw in. The liner here is reinforced to take a toilet - about 10mm thick. Here is a pic of the base on it's mounts, and the liquids tank mounts are visible in the front.

 

Once the mounts are all done, the next issue is to install the vent. This is often the hardest part, from what I've read. In my case it meant drilling a 57mm hole thru the head liner, and the deck. Island time has 2 levels of deck in this area, and there is a drained "hood" over the main cabin for insulation and so the deck lines can be run inside. The vent would be inside the hood. I fitted a piece of PVC pipe sealed to the liner and the deck, to prevent water ingress. The airhead comes with a deckhead fitting for the vent hose. This contains the ventilation fan - a small PC type fan, draws 0.015a at 12v. I wired this to the lighting circuit.  With a couple of cable mount saddles, the vent hose is pretty tidy. Here is a pic of the finished install;

So, now it's time to get it ready to use. It must be filled about 1/2 way with the compost mixture - this is coconut coir. Bunnings sell it for under $3 a brick. A brick looks like this, and is about the size of , well, a brick!

Put the brick in a bucket, add 2 litres of water, and let it soak overnight. Alternatively, add the water and break up the brick by hand. Anyway, what you are looking for is the consistency of damp sawdust - like this;

 

Once it's done, tip it into the base - remember it should be about 1/2 full. Put the toilet unit on the top, replace the liquids tank, and you are ready to go!

The Airhead should take between 60-80 "deposits" before it needs to be emptied. This is approx 1 year for 2 crew weekending, or a month for live-aboard. For most people.

 

Now Island Time has a no discharge system, no pumps, macerators, or holding tanks. I'm pretty pleased with it so far, but I'll add to this in a few months when the Airhead has had some real use.

 

 

This post has been promoted to an article

[Bogan 8]

Thanks for the tip off on where to find the coconut stuff.

 

You can also use peat. Eg: Hauraki gold.

[Island Time 1,235]

Yes Bogan, you can, but peat moss is very slow growing, and hard to replace. Coconut Coir is more environmentally friendly for this reason...

[Island Time 1,235]

Update. The Airhead has been installed for a month now, and has been in use every weekend, incl Easter.

Here are my current thoughts. 

The unit is, as advertised, completely odor free inside the boat (see below). I still find this quite remarkable, but there it is!. It works very well, and even my parents - in their 80's - have used it and commented how easy it is compared to a normal marine toilet. There is a little learning curve (using the paper liners prevents skid marks, and the cleaning they require, but it's not essential) and new guests require a minutes "potty training".

I made an install mistake putting the vent in the space between the decks. The vent expels a musty smell, and in that confined space was unpleasant, as it could come through the gaps where the control lines come into the cockpit. It does not smell like sewerage, but it is not great. So, I moved the exhaust to come out a ventilator on the cabin top, just forward of the dodger. Since then, we have not smelled anything from the toilet. So, it you are going to use one, make sure the vent is properly outside, where any smell is dissipated.  I certainly would not recommend that it is vented into a deck locker, or anywhere in the cockpit.

Otherwise we are really pleased with it.