Holding Tank: Vent Filter

[Capt Ben]

Hi all,

I'm considering installing an activated charcoal filter in-line with the overboard vent. The motivation behind this is to eliminate the stench when using the head and pumping effluent into the head, the vent allows for the displaced gas to escape the tank. Unfortunately, that escaping gas really stinks when pumped. I do not have head odors when not actively using/pumping the head.

Has anyone used these vent filters? A concern that I have is that this filter would impede the flow of escaping 'air' out of the tank when pumping (emptying the toilet) and thus increase the odds of a ruptured or leaking tank.

Here's a link to one I have in mind.SeaLand ECO Holding Tank Vent Filter Kit

Thanks in advance for any advice.

[sailormed]

Improve the tank venting to get an aerobic bacterial growth in the tank. These critters do not produce the stinking gas. Problem solved. Install 2 vent lines to get an airflow in the top of the tank. Put the end of the vent lines on opposite sides of the boat to improve the cross flow.


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[Capt Ben]

Thanks for your response. Frankly, I can't see how adding additional vents will help. When anything is pressed into the tank, skanky 'air' will be displaced. It is that displaced air that I wish to treat. Now, if you are suggesting that if there is enough air flow in the tank that the tank 'gas' won't stink when displaced, that's another possibility but I find that doubtful. There's got to be methane, etc., produced that will stink no mater what eh? Or here's another way I look at it, if I could leave my holding tank access port open wouldn't that always stink?

[peghall]

I can't see how adding additional vents will help. When anything is pressed into the tank, skanky 'air' will be displaced. It is that displaced air that I wish to treat.

What you really want to do is prevent the "skanky" air from being created in the first place...and the key to that is oxygen. Sewage—all organic material--contains both aerobic (needs oxygen) and anaerobic bacteria (functions in the absence of oxygen); but only the anaerobic bacteria produce foul-smelling gasses! Both aerobic and anaerobic bacteria break down organic matter, but when organic matter breaks down aerobically, it converts to CO2, which is an odorless gas, and water. So, as long as there is a sufficient supply of oxygen to the tank, and an aerobic treatment is added to aid that which naturally occurs in sewage, the aerobic bacteria thrive and overpower the anaerobic bacteria, and the system cannot produce odor. No odor, no need for a filter....in fact, because filters impede the free exchange of air in and out the vent, they actually help to create the very problem they're sold to solve.

But there's another reason why filters are a bad idea, especially on most sailboats: they cannot get wet. So a tank that overflows out the vent when sailboat boat heels, or due to overfilling on any boat, will become "toast" immediately...the charcoal can swell and completely block the vent.

There's been a lot of discussion about holding tank odor on this forum...you might want to search for those threads. The link in my signature is worth checking out too.

Peggie
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

[rwidman]

I use Odorlos, a product that lessens or eliminates the odor naturally. I don't remember offhand how but it works. I don't have a filter.


These filters reduce the air flow and contribute to the problem they are supposed to solve and if you ever get one wet you'll have to replace it because it will clog and there will be no venting and no way for air to get into or out of the tank.

[Smokeys Kitchen]

Try using Noflex digestor. It works well for us and the local sailing club uses it of all their boats

[John_Trusty]

Before you install anything, give Raritan KO (Kills Odors) a chance. It sets up a colony of those aerobic bacteria that Peggy talks about and does actually kill odors (go figure!). Anyhow, using according to directions and with adequate ventilation, it works. My $hit don't stink!

[Tayana42]

Read this book. It answered this and others question.

The New Get Rid of Boat Odors: A Boat Owner's Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor https://www.amazon.com/dp/1892399784..._XYw5xb832JKPY


S/V B'Shert

[HopCar]

Tayana beat me to it. Read Peggie's book.
If my memory is working, Peggie developed KO and sold the formula to Raritan.

[patrick brooks]

I have to change out my filter about every year. however as I have tank pump every month, the pump is a self pump cart and if operator has pump reversed what happens is a mess. also reverse pressure forces ==== into and overwhelming filter. after event I have cut old filter and replaced contents with charcoal. fair winds

[S/V Alchemy]

Peggie Hall. That is all.

[JOHNMARDALL]

A properly sized activated charcoal " no smell" filter on the far end of the vent line can help s lot, but select a media pack that also contains silica gel to prevent the charcoal from becoming waterlogged, (when it stops working)
Good luck
John Mardall
Vetus Maxwell Group

[Terra Nova]

Peg--good post.

[davewtsnape]

Odorlos seems to work fine in my tank

[peghall]

Originally Posted by davewtsnape

Odorlos seems to work fine in my tank

Fwiw, Odorlos Odorlos has a much larger presence in the RV market than in the marine market....so it's a lot easier to find and has a much lower price in RV supply stores than from marine suppliers.

If my memory is working, Peggie developed KO and sold the formula to Raritan.

Your memory is only a little off, Hop...we did develop K.O. which was the first bio-active tank treatment (born of necessity to solve a horrible odor problem on my own first boat that had a holding tank) and the "flagship" of our product line. However, I sold the whole product line along with our contract with the lab that made all of them to Raritan, not just K.O. nor the formula.

I appreciate all the plugs for my book...Amazon has it in both Kindle and hardcopy.

Peggie
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein