Foul smelling holding tank!

[Trumpton189]

We have a 35ft river cruiser with stainless holding tank which gives off the most unpleasant odour whenever the toilet is flushed. Tank was emptied during winter maintenance programme at yard and should therefore have little in way of waste content. I am assuming that the smell is caused by fumes from waste residue in tank escaping via the breather / vents on the hull side and have dosed the tank with additional chemical solution with little / no effect.

We took some guests onboard yesterday and the look on their faces when someone flushed the loo told all!!

Any suggestions re: chemicals or actions that might help??

Thanks

 

[Andyroonot]

You can fit a charcoal filter inline to the breather vent-Vetus do one I think, but not no doubt there will others out there

 

[jfm]

You can fit a charcoal filter inline to the breather vent-Vetus do one I think, but not no doubt there will others out there

Agreed. If there's nothing else wrong and it is just smelly air from the vent then those filters work VERY well. Lee Sanitation do a good one

 

[markdj]

I was thinking it is your inlet pipe and not your black water tank. Growth on the inside of the inlet pipe has decomposed over the winter.

I would either change your inlet pipe or take it off and clean the inside of it and see if that helps.

 

[Bilgediver]

We have a 35ft river cruiser with stainless holding tank which gives off the most unpleasant odour whenever the toilet is flushed. Tank was emptied during winter maintenance programme at yard and should therefore have little in way of waste content. I am assuming that the smell is caused by fumes from waste residue in tank escaping via the breather / vents on the hull side and have dosed the tank with additional chemical solution with little / no effect.

We took some guests onboard yesterday and the look on their faces when someone flushed the loo told all!!

Any suggestions re: chemicals or actions that might help??

Thanks

Oh dear......that pong again....

Well in the old days our friend The Headmistress would tell you in graphic details about your anaerobic problems and how to correct them . The charcoal filter isn t really the answer.

The best solution in the UK is provided by a product called Oderlos and one of the few products considered satisfactory by The Headmistress.

http://www.c-b-a.co.uk/latest/odorlos-a-complete-holding-tank-treatment.html?Itemid=2

This is one source but I have no doubt Lee Sanitation sell it also many marinas as I have seen it in a few chandlers in Scotland.

You can also get a product in B and Q but I would have to check out its name. Used by those who are not connected to the sewers.

 

[desiderata]

tank pong

Not being a lover of lots of chemicals I use a much kinder and cheaper solution that certainly works for us - Eco friendly washing powder - each week I put a little into the loo and flush with a reasonable amount of water - when you empty the tank - if the machine is not too tight with the time - put some more in and again a few gallons of water and before leaving the boat for any length of time - again do the same - a bit of washing powder and a few gallons of water - if leaving the boat for the winter it would probably be worth doing this a second time - ok that is an extra pump out and cost but we don't have a smell problem even in the hot weather

 

[TrueBlue]

Another vote for OdorLos.
We tried everything,

• Blue whatsit - more suitable for bucket and chuckit
• Live yeast (works for a couple of days)
• For a couple of seasons force air via an electric dinghy pump through the flush pipe, not very nice while the bubbler is operating, so do it while on the move.
• Then we tried OdorLos; pretty well does what it says on the bottle. Not hugely expensive if you can find the bumper bonus pack. That lasts two seasons - and we use the boat a lot. Good value from Midland Chandlers, but that won't help the OP. It can be made a bit more effective if you umm - stir the contents occasionally; I use a stick...

 

[Who]

Check the breather pipe on the side of the holding tank.

Mine was full of......... well you know.

It was completely blocked, so when we flushed the toilet all the air in the tank ended up inside the boat. I guess forcing its was past various joints and bubling back up in the toilet.

Oh yeah, real unpleasant. But easily fixed

 

[jfm]

. The charcoal filter isn t really the answer

I think that was an imho not a statement of absolute fact. Each to their own but I find a charcoal filter 100pc effective in curing an odour that is simply coming from the vent pipe so I wouldn't use anything else

Headmistress's theory is that smells from vent occur because of bacteria that grow in anaerobic conditions. So she says fit a bigger vent to circulate loads of air into the black tank

With much respect to her I think this theory is flawed. At least' having a big tank vent isn't a complete cure. Everyone knows that shiit stinks as soon as it is dumped. So if person A shiits, then there will immediately afterwards be smelly air in top of tank. If person B uses the loo straight afterwards his pee and flushwater will displace a few litres of that smelly air out of the vent. Having a bigger vent as HM recommends won't change that. A charcoal filter eliminates the smell. Very much not rocket science. All imho

 

[Deleted User YDKXO]

I dont believe that chemicals are the answer. With a well fitted and maintained system, you should not get smells from a holding tank system.
First check that the vent pipe is working. Get somebody to flush a toilet and stick your nose next to the vent pipe outlet. You should be able to hear liquid discharging into the tank and, of course, smell a whiff of stinky air. If you can't, the vent pipe could be blocked. I have used a bit of straightened metal coat hanger to poke up the pipe in the past but be careful. As already mentioned a vent pipe filter is an excellent idea if your vent pipe hasn't already got one. If it has, change the filter element.
Second check around the tank, pump and pipework for any leaks and mop up any standing liquid in the bilges with strong disinfectant. You occasionally find leaks from macerator pumps with failed seals
Third and this is important. Many boat builders do not use sanitation quality pipe for plumbing in their holding tanks and use bilge pump pipework to save cost. This type of pipe becomes porous over time, especially where there may be standing fluid in the pipe, say on flattish pipe runs. Take a piece of dry paper kitchen towel and wipe any pipework with it. If the paper towel smells afterwards, the pipe is porous and you need to replace it. If you're going to replace some pipework, you might as well replace it all just to be sure

 

[nonitoo]

Cannot remember the name but I use an additive, flushed down the loo, each time I empty the holding tank. It's a pale green colour. very effective at de-ponging the contents of the holding tank.

Tom