Peggie, I have a question, kinda related to this thread. I think I've
read/understood that a well "aired" holding tank is the best way
to reduce oders.

Yep...oxygen is the key to odor elimination.

So, being an engineer, I'm wondering if a two
hose holding tank vent arrangement...one "inlet" and one "outlet",
might work.
The forward hose leads to the bow, the aft hose leads to the
stern.

It would actually work better if both lines went forward...'cuz that
would mean air would be forced into the tank no matter which tack you're
on. Nor does it require two vent lines if the vent line is short enough
( 5') and has a 1" ID...'cuz air forced in has no trouble pushing
gasses in the tank out the same line.

The theory is that there would be constant airflow into,
(and out of) the holding tank. assuming the vents at each end
encouraged such flow.

A line leading aft that's too long wouldn't be under enoug pressure to
get the job done without an inline exhaust fan to help it. You'd
actually be better off with a single 1" short vent.


Is this a stupid idea?

Noooo...not stupid at all! It only proves you're thinking in the right
direction. I'd have to see a diagragm of your installation before I
could tell you what you need to do to make it work.

--
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://www.seaworthy.com/html/get_ri...oat_odors.html

Peggie,
Question have you ever heard of or used forded mechanical aeration of marine
holding tanks?
Two options come to mind 1.) install a 10 VDC computer chip cooling fan in a
tank vent line where the tank has two vents. for example a 5.3 CFM (free
air) fan draws 1.08 watts power (at 24/7 operation this is about 2.2 AH
draw) and is about 1-1/2" diameter which can be adapted to fit in-line in
one of the vent hoses. 2.) better solution a battery powered AQUARIUM AIR
PUMP available on the shelf at PETCO for $13.00. It comes with its own air
release stone that would be dropped into the holding tank and feed through a
3/8? O.D. plastic hose that is run-through the wall of one vent line. the
air pump is quite and aerates the stored liquid much as a commercial
wastewater sewage treatment facility not just the surface layer like tank
vents. The air pump is designed to hold two C-size batteries with an
estimated 2-week life or about 1.3 AH on a 24/7 operation schedule. KISS
would be to replace the "Dry-Cells" every two weeks, but if someone wanted
to get really fancy with this installation they could install rechargeable
C-Cells and hook them into either a solar panel (al-a NICRO-VENT or into the
12 VDC "House" battery through a dropping resister to get the 3 VDC at the
air pump.
I realize that these options add another level of complication to the marine
head equation but it does away with all odor problems without the cost of
additional of chemicals.
What is your opinion on either of these mechanical aeration schemes.
Jim Maxey ME

"Peggie Hall" wrote in message
...
Peggie, I have a question, kinda related to this thread. I think I've
read/understood that a well "aired" holding tank is the best way
to reduce oders.

Yep...oxygen is the key to odor elimination.

So, being an engineer, I'm wondering if a two
hose holding tank vent arrangement...one "inlet" and one "outlet",
might work.
The forward hose leads to the bow, the aft hose leads to the
stern.

It would actually work better if both lines went forward...'cuz that
would mean air would be forced into the tank no matter which tack you're
on. Nor does it require two vent lines if the vent line is short enough
( 5') and has a 1" ID...'cuz air forced in has no trouble pushing
gasses in the tank out the same line.

The theory is that there would be constant airflow into,
(and out of) the holding tank. assuming the vents at each end
encouraged such flow.

A line leading aft that's too long wouldn't be under enoug pressure to
get the job done without an inline exhaust fan to help it. You'd
actually be better off with a single 1" short vent.


Is this a stupid idea?

Noooo...not stupid at all! It only proves you're thinking in the right
direction. I'd have to see a diagragm of your installation before I
could tell you what you need to do to make it work.

--
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://www.seaworthy.com/html/get_ri...oat_odors.html

On Sun, 9 May 2004 16:54:04 -0700, something compelled "jmax"
, to say:

What is your opinion on either of these mechanical aeration schemes.

Simpler is better, at least for me. I have ordered a seat that
will sit on top of a five gallon bucket. You line it with a
plastic garbage bag. Use it, tie the bag shut, and store it
until you find a trash can.

No leaks, no clogs, no thru hulls, no funky odor. Yes, it's a
little gross, but not more so than when the whole system packs it
in and you're reduced to hanging it over the rail.

Steve Daniels, Seek of Spam wrote:
Simpler is better, at least for me. I have ordered a seat that
will sit on top of a five gallon bucket. You line it with a
plastic garbage bag. Use it, tie the bag shut, and store it
until you find a trash can.

Your guests should just love that! And how do plan to dispose of the
bucket contents? It's illegal to dump 'em overboard within 3 miles of
the nearest point on the whole US coastline....nor can you put the bags
in a trash can or dumpster legally either.


No leaks...no funky odor.

Wanna bet?

Otoh, you'll have so little invested in it that replacing it with a
viable system won't be financially painful. If you want simple and
cheap, why not just go with a portpotty? Carrying it off the boat to
dump down a toilet legally would be no more effort than carrying bags of
toilet waste off the boat to put a dumpster illegally....but would be a
LOT more pleasant to use.

--
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://69.20.93.241/store/customer/p...40&cat=&page=1

jmax wrote:
Peggie,
Question have you ever heard of or used forced mechanical aeration of marine
holding tanks?

Yep...in fact, Groco makes a holding tank aeration system...they call it
the Sweetank System. See it at http://www.groco.net

Two options come to mind...

You seem to be describing two different systems...a fan in a vent line
doesn't aerate, it only ventilates the airspace above the surface. And
in tanks smaller than about 30 gallons, that aren't more than about 18",
ventilation along with with an organic (bio-active or nitrate) tank
treatment should be enough to create the aerobic environment needed to
prevent odor. It does require two vents, and the fan should be be an
exhaust fan that pulls air through, not one that pushes air into the tank.

An aerator oxygenates the contents, and properly designed and installed
for the size of the tank, completely eliminates odor without the use of
any tank products. But the key is a pump big enough for the tank size,
and a system inside the tank that distributes the air throughout the
whole tank...a too-small pump and/or just a single column of air would
only push noxious gasses out the vent. It's also important to remember
that while fish tanks only contain water, waste is full of animals fats
that routinely clog up gauge senders...and can clog up the aerator too
if the design doesn't prevent it.

By the time you go through all that's needed to design and retrofit a
DIY aerator that won't create more problems than it solves, it might be
cheaper just to buy one. The Groco Sweetank has a list price of around
$250...WM quite often has it on sale for around $150. Even that sounds
like a lot till you compare it to the total amount spent on holding tank
products over a couple of years.

Both aerators and vent fans have to run 24/7/365 (except during winter
layup of course) to keep the tank aerobic. A tank that's turned septic
can be recovered, but it takes several hours, and the odor forced out
the vent is horrific for at least the first hour...then gradually
diminishes over the next 3-6 hours depending on the size of the tank.
That COULD make your battery powered pump a bit problematic if the
batteries aren't changed regularly...and batteries run up the cost too.

IMO, a far better solution than any of the above is a Type I MSD (CG
certified device that treats waste and discharges overboard legally in
all waters except those specifically designated "no discharge," which
are few and far between in coastal waters. Why have to deal with the
problems of storing waste aboard if you don't have to?

--
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://69.20.93.241/store/customer/p...40&cat=&page=1

On Mon, 10 May 2004 15:21:17 GMT, Peggie Hall wrote:

good comments snipped

It does require two vents, and the fan should be be an
exhaust fan that pulls air through, not one that pushes air into the tank.

Peggie, I wondered about your statement above...until it occured to me
that you're entirely correct. The reason (tell me if I'm wrong) is that by
sucking air out, a slightly negative tank pressure is created. This prevents
odors from escaping into the boat via the vent loop, (or any other "air leak"),
which it would if the tank had positive pressure.

I'll probably try this when I (finally) get my own boat, but I'll be sure to
make the fan easily replacable, since I suspect the "fumes" will be
somewhat corrosive.
Norm B.

engsol wrote:
On Mon, 10 May 2004 15:21:17 GMT, Peggie Hall wrote:

good comments snipped

It does require two vents, and the fan should be be an
exhaust fan that pulls air through, not one that pushes air into the tank.


Peggie, I wondered about your statement above...until it occured to me
that you're entirely correct. The reason (tell me if I'm wrong) is that by
sucking air out, a slightly negative tank pressure is created. This prevents
odors from escaping into the boat via the vent loop, (or any other "air leak"),
which it would if the tank had positive pressure.

I dunno about that...I think you're over-thinking it. Compare it to an
attic or "whole house" fan in a house, or even a hood fan over a stove.
They pull air out of the house because that's the most efficient way to
do it. To replace/exchange air being pulled out requires a source...in a
house, the source is open windows or doors...in a holding tank tank it's
a second vent line.

I'll probably try this when I (finally) get my own boat, but I'll be sure to
make the fan easily replacable, since I suspect the "fumes" will be
somewhat corrosive.

More often than not, a single 1" diameter short (3') straight vent line
will work all by itself. It's only when the tank location makes a
short straight vent line impossible that more complex solutions are needed.

--
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://69.20.93.241/store/customer/p...40&cat=&page=1

Peggie, am I remembering correctly that a Type I MSD has to be mounted
lower than the head? In that case, I can never use one 'cause
understandably the head is about as low as you can get on the boat.

Jim.

Peggie Hall wrote:


IMO, a far better solution than any of the above is a Type I MSD (CG
certified device that treats waste and discharges overboard legally in
all waters except those specifically designated "no discharge," which
are few and far between in coastal waters. Why have to deal with the
problems of storing waste aboard if you don't have to?

wrote:
Peggie, am I remembering correctly that a Type I MSD has to be mounted
lower than the head?

No. It only has to sit at OR below the level of the toilet discharge and
be within 6' of the toilet...and a vented loop inline between the toilet
and the device will even allow it to be a little higher. The best pace
on a lot of boats--especially sailboats--is under the vanity in the head.

In that case, I can never use one 'cause
understandably the head is about as low as you can get on the boat.

If that were the case, there wouldn't be much of a market for 'em...'cuz
the heads on most boats are about as low in the boat as you can get.

Btw...this is covered in the installation instructions, which you can
read if you go to the link I gave you.
--
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://69.20.93.241/store/customer/p...40&cat=&page=1

Peggy

I would really like to install an electrasan or other treatment system, but
as near as I can tell ALL of Lake Michigan and Green Bay have been declared
"No Discharge Zones" by Wisconsin and Michigan -- probably others of the
Great Lakes as well. I seriously dislike the idea of discharging into the
lakes, and understand that it's not legal to do so even though a whole lot
of folks do so anyway. My boat will probably be on the hard until next year
anyway, so it's not an immediate concern, and it won't be on the Great Lakes
forever, but I'd sure appreciate any tips you can give me on this topic. If
it's in your book, I can obtain it. ;-)

--
Karin Conover-Lewis
Fair and Balanced since 1959
klc dot lewis at centurytel dot net