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Re: T&T: Re Incinerating and composting toilets

From: Jeff Barfett (no email)
Date: Sun Jan 07 2007 - 21:38:03 EST

  • Next message: Jeffrey Siegel: "Re: T&T: AIS"

    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
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  • Next message: Jeffrey Siegel: "Re: T&T: AIS"



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