Holding Tank Odor

[Cinnamon Girl]

We need some help with ongoing potty odors. Here's the situation:

We liveaboard and have a LaVac toilet, which can be pumped overboard or into a 40 gallon holding tank. When we are away from shore and can pump overboard, there is no issue - in other words, no smell. When we use the holding tank (which is all the time we are at a dock or at anchor), we get an unacceptable odor once the tank begins to fill.

The toilet empties to the holding tank and passes by a vented loop. Oddly, the exit for the vented loop occasionally leaves a trail of effluent dripping down the exterior of the hull.

There is no smell in the "bathroom" on the toilet side. The smell emanates most strongly from the closet where the holding tank resides, and outside when it is really bad. All is worse when the weather is hot and gets worse as the tank gets filled up. We use No Flex Digestor each day. We have replaced the filter for the vent. We have replaced each and every hose within the last 4 months to no avail. We have opened up the holding tank and hosed it out well after emptying. We are at a loss as to what to try next.

Any ideas?

[a64pilot]

Your statement of a vented loop confuses me.
I don't think vent filters are a good idea, I believe the larger and more unrestricted a vent can be, the better.
Your source for the odor I believe may be the vent, hopefully not the tank leaking


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[JPA Cate]

Cinnamon Girl,

You might want to have a look at the two threads running now about "composting toilets".

There are a number of members who use them and prefer them to holding tank systems.

Ann

[westsailwill]

Ditto that!

[svlamorocha]

Originally Posted by Cinnamon Girl

We need some help with ongoing potty odors. Here's the situation:

We liveaboard and have a LaVac toilet, which can be pumped overboard or into a 40 gallon holding tank. When we are away from shore and can pump overboard, there is no issue - in other words, no smell. When we use the holding tank (which is all the time we are at a dock or at anchor), we get an unacceptable odor once the tank begins to fill.

The toilet empties to the holding tank and passes by a vented loop. Oddly, the exit for the vented loop occasionally leaves a trail of effluent dripping down the exterior of the hull.

There is no smell in the "bathroom" on the toilet side. The smell emanates most strongly from the closet where the holding tank resides, and outside when it is really bad. All is worse when the weather is hot and gets worse as the tank gets filled up. We use No Flex Digestor each day. We have replaced the filter for the vent. We have replaced each and every hose within the last 4 months to no avail. We have opened up the holding tank and hosed it out well after emptying. We are at a loss as to what to try next.

Any ideas?

The holding tank may have a leak (of liquid or gases).

The hoses may permeate odors. Wipe them with a wet paper towel and you will find out if there is permeation going on.

Smell may be coming out of the vent on the side of the boat (the one that is connected to the top of the tank, not to the toilet). If that is the case the best solution depends on how you use the boat.

If you will use the tank only ocasionally (sat 2-3 day trips from USVI to BVI) and can rinse after each use then you can use those chemicals, enzimes, etc that will deal with odors but keep the process anaerobic.

If you want a long-term solution you have to increase the diameter of the vent fitting and hose and add another vent (ideally connected to the other side of the hull) to get cross flow. This will just stop the generation of odor.

Google "peggy hall head mistress"

Enjoy

[peghall]

Originally Posted by Cinnamon Girl

We need some help with ongoing potty odors. Here's the situation:

The toilet empties to the holding tank and passes by a vented loop. Oddly, the exit for the vented loop occasionally leaves a trail of effluent dripping down the exterior of the hull.

The vented loop is needed in any toilet discharge line connected to a below waterline thru-hull.. Someone has made the mistake of putting a vent line on yours instead of an air valve. That's a bad idea because that vent line has such a small diameter--just 1/4"--that it quickly clogs up with solids and sea water minerals, turning the loop into an UNvented loop that no longer has any ability to break siphon. The air valve that should be installed in the loop only opens when liquid is being PULLED through a line...waste is being PUSHEd through the toilet discharge line, so there wouldn't be any squirting or need for the vent line if it were installed correctly. There's nothing odd about the "effluent trail" on the hull...the pressure from the Lavac pump would be creating a squirt out the hull if the vent line off the loop weren't so clogged up.

There is no smell in the "bathroom" on the toilet side. The smell emanates most strongly from the closet where the holding tank resides, and outside when it is really bad.

Unless a tank is leaking, it's rarely if ever the source of odor INSIDE the boat 'cuz odor from inside the tank has only one place to go: out the tank vent. That you have odor inside the boat AND odor out the vent suggests you have TWO problems: holding tank odor (odor out the vent) and a different source of odor inside the boat. Permeated sanitation hoses are the most likely culprit, even though you've recently replaced them if you used the least expensive single wall flex PVC (#148) sanitation hose. It permeated on my own boat in less than 90 days! Another possibility is residual odor from any spill when you replaced the hoses...bleach does not do a good job of completely eliminating it. If you'd like to discuss all the possible sources and cures, you're welcome to email me/

All is worse when the weather is hot and gets worse as the tank gets filled up.

Not surprising...bacteria creates odor, bacteria are more active when they're warm.

We use No Flex Digestor each day.

No Flex digests and liquifies sludge, but can't do much to PREVENT odor in an anaerobic environment, which putting a filter on the tank vent line creates. Get rid of the filter and try a product called Odorlos Odorlos
The active ingredient is nitrates which promotes oxygen release from the waste itself, helping to create the AEROBIC conditions needed to prevent odor from occurring. Both marine and RV supply stores carry Odorlos, but the RV store prices are a LOT lower than marine!

We have replaced the filter for the vent. We have replaced each and every hose within the last 4 months to no avail. We have opened up the holding tank and hosed it out well after emptying. We are at a loss as to what to try next. Any ideas?

Finding and eliminating all the sources--the REAL sources--of odor(s) is the only way to eliminate odors...'cuz as long as the source continues to exist it'll continue to generate odor. So we just need to hunt down and eliminate your odor sources to solve your problems. and I'll be glad to help you do that.

[peghall]

Originally Posted by svlamorocha

Google "peggy hall head mistress" Enjoy

She'd prob'ly have more luck if she spells my name correctly.

[Sailmonkey]

It's like beetlegeuse!!
Peghall
Peghall
Peghall


And she appears!!



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[Cinnamon Girl]

Thanks to all. Peggie, I will be in touch with you directly!

[Garreth]

Theres a product called the commoderizer. It works wonders and is being used in the moorings charter fleet world wide. It really really works.

[CHM]

A vented loop to the holding tank? Am I missing something? Sounds like a vent issue (anaerobic bacteria). or bad connection at the holding tank?


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[peghall]

Originally Posted by CHM

A vented loop to the holding tank? Am I missing something? Sounds like a vent issue (anaerobic bacteria). or bad connection at the holding tank?

If there's a y-valve in the toilet discharge line that provides the ability to flush directly overboard at sea, yes a vented loop is needed. It's often installed ahead of the y-valve because a) that's the easiest place to put it, and b) once the flush clears the top of the loop gravity gets it the rest of way, reducing the amount of flush water going into the tank....which can be a good reason to put a loop--though not necessarily a vented loop--in a line that only goes to the tank.

Fwiw, you've tapped into a thread that's several months old...the OP and I have solved her problems, both here and on the phone. You might want to read post #7 ...my replies to her are bit tricky to separate from her questions because both became italicized when it was quoted, but I think you can sort them out...and I'll be glad to answer any questions you may have.

[CHM]

My mistake. I didn't pay attention to the dates and I see your point of a loop in that configuration and swear by Odorlos. Thanks!


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