Hugely smelly holding tank

C

ChrisE

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We used to praised about the pleasantness of our heads but no longer since the fitting of a holding tank. I'm now under some pressure to find a solution to said pong, so...

I've done a search on this ever popular topic and come to the following conclusions:

1. All holding tanks smell sooner or later
2. Charcoal filters help reduce the smell
3. Only way to get rid of pervading stench is to fill holding tank with water, pump out, maybe several times.

Last question, is there any merit in adding some kind of non-pong product to the tank after said pump outs or are we just stuck with the smell?

TIA
 
We've not had any smells from our holding tank since fitting it a few years ago, even after removing the charcoal filter because it caused more problems than it solved: they don't work if they get wet, and I'd rather not recall the details of precisely how that happened. /forums/images/graemlins/tongue.gif According to Peggy Hall the way to prevent smells is to ensure good air circulation in the tank, i.e. a decent diameter, unfiltered air vent. It's anaerobic decomposition that smells, and perfumes to mask the smell are just that. You could put bleach or other antiseptic stuff down the loo, but that would have to be a continuing process.
 
Only time I had a "holding tank" was when I had a chemical portable, then the "holding tank" not only holds the waste, but gets a flush of sweet smelling chemical each time. I think I would ensure the holding tank was flushed thoroughly then put a drop of elsan, or some such product in.
 
We try never to use it, such is the pong emitting from said tank. It was fitted in 2005 for the trip to Norway and in the event it was used about twice and this is the legacy we now have. I suspect that if we lived aboard and used it regularly this would not be a problem. The fact that it is just sitting there is probably exascerbates the pong
 
Peggie Hall an american lady we so dearly miss waxed lyrical on this subject and has written books telling how to live with holding tanks. Her latest book about Boat Odors is in Print and available from Amazon however the earlier book is available on various sites Fact V Folklore .

Your basic problem is ventilation of the air space of the holding tank. Your breather is too small and not working.I believe Peggie suggests 1" breathers in her latest book with breathers from each side of the boat if possible so that the tank is maintained in an aerobic state.

Read Ms Halls book as above and although the treatment chemicals she refers to are not readily available you can get substitutes in some marinas and also the B and Q warehouse which it sells for cesspits. I suspect Lee Sanitation may also be able to help.

As my good friend Peggie says.....holding tanks should not smell!!!!
 
Having a good size vent (25mm +) is important. I suspect that if it is fitted below the water line and emptied by a pump or macerator that is never really empties. Plus you are likely to have waste in the pipe runs if they are long or have dips. If you don't intend using it, I would suggest completely flushing it and disconnecting.

I note that many builders are now installing gravity tanks on bulkheads or in lockers above the water line. The obvious advantage is that they can be emptied and flushed easily. I fitted one to my boat and have no problems.
 
You could put bleach or other antiseptic stuff down the loo, but that would have to be a continuing process

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Oh dear....Peggie would have a fit if she read this and you were doing so well up to this point /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

No bleach should go into the loo when using the holding tank. You have to use the correct cleaners which rely on bacteria and enzymes and other such.....These are now appearing in the supermarkets as bleach is a No No on the industrial scene .

Bleach kills the action in the holding tank..!!!!
 
[ QUOTE ]
Bleach kills the action in the holding tank..!!!!

[/ QUOTE ]
/forums/images/graemlins/blush.gif
Well, I know that really, honest, but to be fair that is what was being asked. It's all very well saying that the air vent is too small but fitting a larger one may not be a realistic option, either physically or because the crew have no faith that it will work. In which case you're talking about chemical warfare, and I guess it's really a matter of what you want to pump into the sea (if you dump at sea) along with the fertiliser.
 
What type of installation is it? If it is a wrap-around tank there are specific problems that I may be able to help you with.

Peggie Hall's extremely comprehensive booklet on marine sanitation can be read in full here. Few posters on this forum will be able to match the depth of knowledge displayed here.

So far as the new bio-type additives are concerned, we have found them to be rather disappointing, both in the boat and in our motorhome. When the boat holding tank is working well it is completely smell free but we have encountered considerable H2S generation when the problems referred to above were active. We think we have now got to the bottom (!) of these.
 
I think your problem is ventilation. I decided to go for a 38mm straight vent from the tank, emerging just under the rubbing strake and we haven't had a problem. The other possibility is poor pipe runs. If you have loops and dips where bad stuff can lie, the pong will come back through the loo bowl. As dear Peggy would say, a proper holding tank installation should not smell. Has it always smelled? Did you install it? If you had it done for you, get the people back to fix it. Otherwise I would recommend a close inspection (with nose clip in place!) to see what might be wrong. I reckon if you increased the ventilation (38mm) and got the pipe runs right, your problem would be solved. Don't bother with charcoal they are a pain in the a***.
 
Thanks all for the advice and guidance and the pointers to Peggie's advice

Good news is that we've got a 50mm vent. The vent runs vertically up from the tank so don't think loops and dips will be a problem.

Bad news is that the vent is in the heads compartment so any pong wafts romantically through the boat. Like Vyv, there ain't much we don't know about H2S production.

So looks like the plan a will be dump filter, flush tanks with salt water and hope that the additional venting will do the trick. Otherwise, plan b will be flush and then block off until we find ourselves on board for a while in a place where holding tanks are needed.

Thanks again for all of the advice. Mrs_E will be one pleased person when (if?) we get back to our original state of grace.

Edit, having read Peggie's advice the problem would seem to be the vertical vent pipe which would not allow the exchange of C02. So looks like plan b is the only option unless someone tells me that they have a non-whiffy holding tank with 3 foot vertical vent pipe......
 
Edit, having read Peggie's advice the problem would seem to be the vertical vent pipe which would not allow the exchange of C02. So looks like plan b is the only option unless someone tells me that they have a non-whiffy holding tank with 3 foot vertical vent pipe......
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Peggie accepted that sail boats could present a problem for vent installations and taking the vent up above the deck will help however is it possible for you to add a second vent in from the side of the boat to enable circulation within the holding tank.

One problem with the original vent discharging above the coach house will be that you are down wind in the cockpit everytime someone flushes the heads. If you could get more O2 into the tank then the pong is reduced . /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

I suspect there will be more and more threads like this as holdng tanks are fitted in Europe so maybe time to invite Peggie to give a seminar at the boat show /forums/images/graemlins/smile.gif
 
We have a large S/S holding tank that has to be pumped out overboard or sucked out via a deck fitting. The vent is small diameter run some distance to near the transom and with no filter. We get absolutely no smell whatsoever either when the tank is in use or is empty. We use the holding tank in marinas, harbours and anchorages as deemed necessary and pump it out when the opportunity arises offshore, then pump in a gallon or so of fresh seawater to flush it out, followed by a 2nd refill that is left a while to slosh around before that too is pumped out. We never use any chemicals in the holding tank.

Are you sure it really is the tank or it's contents that is smelly and not old pipework, or even that it isn't the inlet pipe H2S organism you are smelling? We had a Lavac on our last boat that had a pinhole in the diaphragm on the pump which let the smell out via a telltale hole in the back of the pump housing, the pump still worked but a new diaphragm cured the escaping pong.
 
In which case you're talking about chemical warfare, and I guess it's really a matter of what you want to pump into the sea (if you dump at sea) along with the fertiliser.
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One product that got the thumbs up from Peggie and is now available in the UK is Odorlos This will reduce the pong even in anaerobic conditions and should be OK .. I f you visit one of those new Supa Dupa B&Q warehouses you will find a product hidden in one of the corners marked for Septic tanks and this has similar properties. Do not put bleach in the system if using any of these as it kills the bugs and the pong will get worse again.
 
Vyv, you're right it is inside the boat.

Robin, unlikely to be old pipework as it was all replaced 3 years ago, when the tank was installed.

Sounds as though the way forward in the long term will be an external transom vent a la Robin and in the mean time bung the bloody up....
 
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