Is it possible for odors to come from the holding tank during the flush cycle of the head? I seem to notice oders after switching to the Elegance. I'll need to sniff around. It is not the hoses, all new. I did a search for how to make a vent filter but could locate the thread. Thanks, Chuck
Holding Tank Odor
- Thread starter woodchuck
- Start date
- Joined
- Feb 28, 2007
- RO Number
- 25362
- Messages
- 3,996
Chuck,
A vent filter can easily be made, or buy one of the over-priced models and then refill it yourself when needed.
Or...
Get more O2 into your tank along with Raritan KO and the odors will go away. Typical holding tank vents are only large enough to allow air to vent in and out of the tank when filling or emptying. They do not allow enough air into the tank for aerobic bacteria to grow (the kind that doesn't smell). Instead, only anaerobic bacteria grows, and that's what you're smelling. I used to use a tank filter, but once I learned this trick I figured there's no need to have all that smelly stuff working it's way into the tank walls over time. If you do not want to install a larger vent and hose (I think 1.5" or larger is required), you may also find results by installing a check-valve on the tank along with an aquarium air pump. I took this route as it was easier and I've had good luck for 3 years now. I think the whole project cost me about $30 at PetSmart.
A vent filter can easily be made, or buy one of the over-priced models and then refill it yourself when needed.
Or...
Get more O2 into your tank along with Raritan KO and the odors will go away. Typical holding tank vents are only large enough to allow air to vent in and out of the tank when filling or emptying. They do not allow enough air into the tank for aerobic bacteria to grow (the kind that doesn't smell). Instead, only anaerobic bacteria grows, and that's what you're smelling. I used to use a tank filter, but once I learned this trick I figured there's no need to have all that smelly stuff working it's way into the tank walls over time. If you do not want to install a larger vent and hose (I think 1.5" or larger is required), you may also find results by installing a check-valve on the tank along with an aquarium air pump. I took this route as it was easier and I've had good luck for 3 years now. I think the whole project cost me about $30 at PetSmart.
- Joined
- Jan 1, 2000
- RO Number
- 847
- Messages
- 249
mixman, Can you share your design or talk us thru what you did using the air pump to introduce more are into your holding tank?
Thanks
Jim
Thanks
Jim
- Joined
- Feb 28, 2007
- RO Number
- 25362
- Messages
- 3,996
Jim, do you really want to get more into my holding tank? 
What I did was simple. I have a 20 gallon holding tank. I bought an aquarium pump rated for a 30 gallon tank. I drilled a hole in the top of the tank just large enough for the check-valve to fit in and connected the air pump to it. The pump is 110v AC, so it run only when connected to shore power or the generator is running. However, we've anchored for times as long as a week and since I run the genny a few times a day, enough O2 gets into the tank to keep the "good" bacteria alive. You can make things simpler by installing a wider vent hose. To be honest, Vic at Raritan pointed me to some articles by "the Head Mistress": Peggie Hall, and I just did what she's been suggesting for years.
From: http://boatbuilding.com/article.php/MarineSanitationFactvsFolklore
I recommend you read the entire article, but here's the vent line part of it:
In the holding tank, the key to odor control is the vent line; it must allow a free exchange of fresh air for the carbon dioxide generated by the sewage. Therefore, those bladder tanks which have no vent are all but guaranteed to stink; there’s no source of air into them at all. Boat builders, boat owners and boat yard personnel who install holding tanks have always viewed the vent line only as a source of enough air to allow the tank to be pumped out without collapsing and as an exhaust for methane (Many even believe methane--which in fact is odorless--to be the source of odor.) Some take the attitude that tanks are going to stink so the thing to do is run that vent line as far from people areas—cockpits, sun decks, etc.—as possible, or make the line as small as possible, or install a filter in it. All of the above actually create the very problem you want to solve.
Think of the holding tank as a stuffy room which needs to be aired. You know that even if there isn’t a hint of a breeze outside, just opening a window will allow the fresh air outside to exchange with stuffy air in the room. Open another window for cross-ventilation, and the air exchanges even faster. However, just opening a skylight accomplishes nothing unless there’s also a mechanical means (an "attic fan") of pulling the air up and out--and that won’t work unless another window is open to create airflow. But the only "window" into a holding tank is at the end of a "hallway"--the vent line. If that "hallway" is too narrow and goes around corners, takes a long and curved path, or rises more than 45 degrees above horizontal, no ambient air can find its way to the tank to dissipate and exchange itself with the gasses in it.
Vent the tank with as short, as straight, and as horizontal a line as is possible, with no sags, no arches, and no bends. The minimum I.D of the hose (which is the "standard" size in use today, but for no reason other than being "standard" in fresh water and fuel tainks) is 5/8"; we recommend that it be at least 3/4". Ideally, it should be no more than 3’ long. If it has to be substantially longer, or if running the vent line uphill more than 45 degrees off horizontal can’t be avoided, or if it’s impossible to run a vent line that does not go around a corner, increase the size of the vent line to 1" or even larger. If, for instance on a sailboat, the line must go up to the deck, install a second vent line in order to create cross ventilation, or install some mechanical means of forcing air through the tank. We prefer to put holding tanks in the bow of sailboats--under the v-berth--because the hull just behind the point of the bow is the only place on the hull except the transom that will never be under water even when the boat is at maximum heel; it’s the perfect place to install vent-line through-hulls, because the though-hull is always into the wind, forcing air into the vent line, when the boat is underway or on an anchor or mooring. The vent through-hull should not be the same type as a fuel vent through-hull (a cap with a slit in it), but should be a should be a straight open type through-hull.
Copyright 1997 by The Hall Group, Inc. All rights reserved.
What I did was simple. I have a 20 gallon holding tank. I bought an aquarium pump rated for a 30 gallon tank. I drilled a hole in the top of the tank just large enough for the check-valve to fit in and connected the air pump to it. The pump is 110v AC, so it run only when connected to shore power or the generator is running. However, we've anchored for times as long as a week and since I run the genny a few times a day, enough O2 gets into the tank to keep the "good" bacteria alive. You can make things simpler by installing a wider vent hose. To be honest, Vic at Raritan pointed me to some articles by "the Head Mistress": Peggie Hall, and I just did what she's been suggesting for years.
From: http://boatbuilding.com/article.php/MarineSanitationFactvsFolklore
I recommend you read the entire article, but here's the vent line part of it:
In the holding tank, the key to odor control is the vent line; it must allow a free exchange of fresh air for the carbon dioxide generated by the sewage. Therefore, those bladder tanks which have no vent are all but guaranteed to stink; there’s no source of air into them at all. Boat builders, boat owners and boat yard personnel who install holding tanks have always viewed the vent line only as a source of enough air to allow the tank to be pumped out without collapsing and as an exhaust for methane (Many even believe methane--which in fact is odorless--to be the source of odor.) Some take the attitude that tanks are going to stink so the thing to do is run that vent line as far from people areas—cockpits, sun decks, etc.—as possible, or make the line as small as possible, or install a filter in it. All of the above actually create the very problem you want to solve.
Think of the holding tank as a stuffy room which needs to be aired. You know that even if there isn’t a hint of a breeze outside, just opening a window will allow the fresh air outside to exchange with stuffy air in the room. Open another window for cross-ventilation, and the air exchanges even faster. However, just opening a skylight accomplishes nothing unless there’s also a mechanical means (an "attic fan") of pulling the air up and out--and that won’t work unless another window is open to create airflow. But the only "window" into a holding tank is at the end of a "hallway"--the vent line. If that "hallway" is too narrow and goes around corners, takes a long and curved path, or rises more than 45 degrees above horizontal, no ambient air can find its way to the tank to dissipate and exchange itself with the gasses in it.
Vent the tank with as short, as straight, and as horizontal a line as is possible, with no sags, no arches, and no bends. The minimum I.D of the hose (which is the "standard" size in use today, but for no reason other than being "standard" in fresh water and fuel tainks) is 5/8"; we recommend that it be at least 3/4". Ideally, it should be no more than 3’ long. If it has to be substantially longer, or if running the vent line uphill more than 45 degrees off horizontal can’t be avoided, or if it’s impossible to run a vent line that does not go around a corner, increase the size of the vent line to 1" or even larger. If, for instance on a sailboat, the line must go up to the deck, install a second vent line in order to create cross ventilation, or install some mechanical means of forcing air through the tank. We prefer to put holding tanks in the bow of sailboats--under the v-berth--because the hull just behind the point of the bow is the only place on the hull except the transom that will never be under water even when the boat is at maximum heel; it’s the perfect place to install vent-line through-hulls, because the though-hull is always into the wind, forcing air into the vent line, when the boat is underway or on an anchor or mooring. The vent through-hull should not be the same type as a fuel vent through-hull (a cap with a slit in it), but should be a should be a straight open type through-hull.
Copyright 1997 by The Hall Group, Inc. All rights reserved.
- Joined
- Mar 5, 2001
- RO Number
- 3655
- Messages
- 1,800
For the record - Peggie Hall is not in any way associated with Raritan Engineering Company any longer. Back in the '90's, Raritan bought her company and at that time, she came onboard with Raritan for a year. This was to integrate her accounting and inventory systems with Raritan's, and help ease the pain of transfer, as well as to familiarize Raritan employees with her product line, which had been added to Raritan's product line. When the year was up, she went out on her own and is now a private consultant.
She and I established a friendship at that time and remain friends to date. She preceeded me as the moderator on this board, and when she left to pursue other interests (she was writing a book at the time), she recommended me to Les, to succeed her. Her article, "Fact vs. Folklore" has become a legend in the industry, and was the base article which she substantially expanded upon, to write her book. Under the terms set up with her publisher, because the information is also in her book, it is now copyrighted and she had to remove the article from the internet, where it had been posted for many years - so you won't likely find it any longer.
She still moderates another Forum on a sailboat site, and many people think she is on Raritan's staff, because she touts Raritan products quite freely. But she hasn't received a Raritan paycheck in better than 10 years.
She and I established a friendship at that time and remain friends to date. She preceeded me as the moderator on this board, and when she left to pursue other interests (she was writing a book at the time), she recommended me to Les, to succeed her. Her article, "Fact vs. Folklore" has become a legend in the industry, and was the base article which she substantially expanded upon, to write her book. Under the terms set up with her publisher, because the information is also in her book, it is now copyrighted and she had to remove the article from the internet, where it had been posted for many years - so you won't likely find it any longer.
She still moderates another Forum on a sailboat site, and many people think she is on Raritan's staff, because she touts Raritan products quite freely. But she hasn't received a Raritan paycheck in better than 10 years.
quote:
Originally posted by mixman
Jim, do you really want to get more into my holding tank?
I'm usually the first person to shoot down a hairbrained idea, but how about this:
An adapter that screws into the pumpout deck fitting and an air pump capable of pumping a small amount of air into the tank through the pumpout fitting.
This would introduce fresh air into the bottom of the holding tank and it would bubble up through the contents and exit through the vent.
In theory, this would help to speed up decomposition of the sewage. It might also stink for a while but increasing the venting will do the same.
- Joined
- Mar 5, 2001
- RO Number
- 3655
- Messages
- 1,800
Ron, in theory I see no problem at all with your idea. The only glitch I see, is that you say pump "a small amount" of air into the tank. A small amount won't do it - you'd need a fairly large maount of air being pumped into the tank, in order to do any good.
Somehow there is a way to force air down the pumpout outlet, while docked, providing enough oxygen to the holding tank, promoting enough areobic bacteria growth to sustain while boating for a weekend, or night out on the water. Aquarium pump, small air pump, something quiet, could run 7-24 while not at the boat, could be on a timer, easily removed, easy to store, it ain't rocket science. . . .nobody's figured out what it is yet. . . .does the oxygen need to be actually bubbling in the poo, or is enough to be ambient in the holding tank ?
Capt. Bill1
Active member
- Joined
- Jan 1, 2000
- RO Number
- 2017
- Messages
- 6,127
You'd need a fair amount of pressure and volume to do any good.
Unless the vent was fully clogged or shut off there is no way you could "explode" the tank.
I figure any volume is better than nothing which is what's there now.
As I think about it, there has to be enough pressure to overcome the weight of a full tank of sewage. Think of blowing through a straw set to the bottom of a glass of iced tea.
And of course, it's possible for the vent to become blocked so there really should be a presure limiting system of some sort.
As I think about it, there has to be enough pressure to overcome the weight of a full tank of sewage. Think of blowing through a straw set to the bottom of a glass of iced tea.
And of course, it's possible for the vent to become blocked so there really should be a presure limiting system of some sort.
- Joined
- Feb 28, 2007
- RO Number
- 25362
- Messages
- 3,996
The 30-gallon rated Aquarium pump I've had connected through the top of my 20 gallon holding tank has been doing fine for 3 years now. It runs 24/7 (except when not connected to AC power) to keep the good little critters alive. And since the experts agree that the "correct" solution is a larger vent line, it would seem ambient oxygen is enough. I get the idea of bubbling and I think that's how the "Sweet Tank" system works. But to just force air down the pumpout hose would only bubble the area around the hose, wouldn't it? Not the entire bottom of the tank.
What we should all do is install the larger vent hose. I just got lazy with the pump.
I started leaving the cap off of my pumpout about a month ago. (Creating a rally big vent) I also added the granular Rid-x septic tank treatment and gave it a couple of flushes. Results are inconclusive because I haven been able to boat much this summer, this weekend will tell the tale, flush and have odor, or flush and none. . . .
Here's what their web site says;
RID-X® Septic System Treatment contains billions of 100% natural active bacteria and enzymes to break down household waste. By adding RID-X®, you restore the delicate balance of beneficial bacterial and enzymes needed to help keep your system operating at full efficiency. Each box and bottle of RID-X® contains the following ingredients scientifically proven to break down houshold waste
Cellulase breaks down toilet paper, vegetable matter and some foods
Lipase breaks down fats, oils and grease
Protease breaks down proteins
Amylase breaks down starches
Can't be any worse than the perfume based, or formaldehyde ladened chemicals that are available.
I'll report back after this weekends adventure.
Here's what their web site says;
RID-X® Septic System Treatment contains billions of 100% natural active bacteria and enzymes to break down household waste. By adding RID-X®, you restore the delicate balance of beneficial bacterial and enzymes needed to help keep your system operating at full efficiency. Each box and bottle of RID-X® contains the following ingredients scientifically proven to break down houshold waste
Cellulase breaks down toilet paper, vegetable matter and some foods
Lipase breaks down fats, oils and grease
Protease breaks down proteins
Amylase breaks down starches
Can't be any worse than the perfume based, or formaldehyde ladened chemicals that are available.
I'll report back after this weekends adventure.
I'm not positive, but I will check, thought the pump out tube came in from the top, and had an extention that placed the tip of the tube within inches of the the bottom of the tank.
Which still (as you pointed out) renders it not a good source of oxygen. Minimal at best. . .
If it's not as close to ther bottom (internally or externally), as possible, it will leave a lot of sewage in the tank. Anything below the pickup tube or fitting stays in the tank.
Stick a straw in a glass of water with the bottom of the straw an inch from the bottom of the glass. Suck the water out and what remains? One inch of water.
- Joined
- Mar 5, 2001
- RO Number
- 3655
- Messages
- 1,800
The Groco "Sweet Tank" system and most type II systems that utilize air pumps, all have the inside of the tank bubbling from the air being pumped into the tank.