T&T: Re Incinerating and composting toilets

[Jeff Barfett]

I have been using the AIRHEAD toilet for 3 years now and want to add my
comments to Peggy's. (Peggy's post is below)

First I find the unit very satisfactory over the marine head / holding tank
scenario that it replaced on my boat. The urine storage situation is
manageable and even if you have to pump it to an onboard tank, it is much
more reasonable than have a black tank. Urine is sterile as it leaves the
body (verified by my Urologist) I see no issue in pumping this overboard if
you have the same options with other marine systems as they can't sterilize
urine any more than what it leaves the body - but laws are laws....

The system is engineered so that the urine is diverted and isn't
contaminated, so e-coli isn't an issue.

Most users of the Airheads these days are using Coir, instead of peat,
"coir" is the short name for coir fiber pith, the residue of the process
that extracts the long fibers from coconuts. Those long fibers have been
used for floor mats, basket liners, and lots of other things, but until
recently, the residue was just tossed into piles. In Sri Lanka, some of
those piles are a hundred years old! Coir acts very much like peat and has
high lignin content. Lignin is an organic substance that, with cellulose,
forms the chief part of woody tissue. It is the lignin that provides the
longevity. Coir is an organic material that breaks down very slowly. It
holds water and nutrients beautifully. And it will not waterlog.

This Coir is purchased as 2 X 4 X 8 bricks, which are compressed 8-to-1 it
weighs 1.5 pounds. One brick expands to make between 2 to 2.5 gallons worth
of coir bedding material. 2 bricks make enough for the initial load and a
few quarts extra. So, you can store a few years worth of material in a very
small space.

As for adding peat in every flush - I find we only add a quart of the medium
about once a month. We find that the composting action and the drying
process require one to add water to the pile once a week to keep it from
drying too much.

With 2 of living aboard, we get about 2 months of usage before having to
recharge the unit with more Coir. In the holding tank days, we got maybe 5
days between pump outs.

The Airhead uses 12volt power - it has a small computer fan which creates a
negative pressure in the tank and is exhausted to the outside. The fan
consumes .050 amps / about 1.2 amps per 24 hours. Also helps a little in
ventilation of the boat as a bonus.

The system utilizes a 1.5" vent and as far as I know, always has. While we
are on this subject the air coming out the vent, doesn't smell anything like
a vent on a holding tank, the smell is more like a dense forest smell. Ever
been close to your holding tank vent when someone else 'flushes' the toilet?

As far as the composting working only above 70 degrees, Geoff Trott, the
originator of this system has studies to show that even with the air
temperature of 35 degree's in the room where the toilet sits, the core
temperature of the composting is above 65 degrees and is still active. The
drying and the composting are still going on. Geoff really likes to educate
people on how the composting process works.

Airhead recommends if you store the boat unused for the winter that you
leave the compost over the winter to continue the process and to recharge
during decommissioning in the spring.

Composting toilets are not for everyone, like all things with boats, it has
its own compromises. I find that this process is a lot more earth friendly
that the alternatives. This system makes great compost; it doesn't stink and
if left to completely finish the composting process, will kill off any bugs.

 One of my best boat maintenance days was when I determined the Airhead was
a permanent solution for ME, and was thrilled recapturing the space that a
40 gallon holding tank took up, 30' of $8+ stinky hose, a number of valves,
a macerator pump, wiring, switches and sealing some of the holes in the
bottom of my boat.

One of the unfortunate situations on my boat was the problem of the sewage
hose running uphill to the tank, which always left something in the lines
and created a situation of replacing hose every 18 months to keep the stench
down.

No financial interest in this company, just a happy user and one of the few
that seem to have actual usage history and facts.

Jeff on Southern Nights



(Peggy's post - left intact; too difficult to snip)

The AirHead http://www.airheadtoilet.com (which is not a true composter
but a dessicator) is small enough to fit in most heads, but has the same
drawback as a composter, which are:

1. What to do with excess liquids. 90% of human waste IS liquid...mostly
urine, but even solids are mostly liquid. Excess liquids have to be
drained off , or you have wet soggy organic material...and wet soggy
material doesn't compost.   Adding dry material--peat moss is the
recommended material 'cuz it breaks down quickly--to each flush helps
some, but not enough, and there's usually more liquids than the
evaporator--which, btw, requires power--in the self-contained units can
handle either. The AirHead separates urine from solid waste--the urine
is directed into in gallon jugs (or a tank.  You can't legally drain
liquids overboard (unless you're at sea beyond the 3 mile limit),  so
the jugs must be stored and carried off the boat for disposal ashore...
tank must be pumped out same as any other tank.

2. Enough peat moss to keep the thing working during an extended cruise
can take up more storage space than a holding tank.

3. Composters need a 3" vent stack... AirHead originally specified a 3
vent but is now claiming that a 1.5 vent is adequate.

4. Continuous power 24/7  to run the evaporator.

5. Composting only works in temperatures above 70 F. Below 70, bacterial
activity becomes so sluggish that nothing happens.

As for incinerating toilets They only run on 115v/ac power, and
contrary to popular belief, everything doesn't turn to ash in a "whoosh"
of heat with each flush. The burn time is 90 minutes at something like
1100 degrees F...which is a lot of power and a lot of heat...and even 90
minutes isn't enough time to completely reduce everything to ash. Plus,
incinerators also need a 3" vent/smoke stack, and unless the catalytic
converter is cleaned regularly, the smoke STINKS!  You can read the
maintenance instructions for the Incinolet here: http://www.incinolet.com/

IMO, your best bet is a CG certified Type I or II  MSD (treatment
device) and a small holding tank for use only when you have no other
choice.

--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books/detail-books.htm?fno=0&sku=90&cat=1304