Deep clean sewage tank

[bazjude2998]

I know you may think this is the wrong forum.I have tried boats planes.I have a 20yr old narrow boat.It has a sewage holding tank 300 litres (125 mm deep)tank has to be pumped out when full we add chemical Blue at the advised amount (apparently too much will kill the good bacteria as well as the bad )Suffering smells which I think is down to a build up over the years of nasties.What chemicals could I use to deep clean the tank.No way of getting into tank to power wash out.Dont won't to risk cutting a access into tank.Any suggestions apart from scuttlein.

[Paul Drawmer]

I think that the difficulty you have in finding answers to this is that it is rarely done.

I would have thought that the holding tank is always going to smell nasty, and that your problem is more likely to be related to how the waste flows into the tank and possible cracks or holes in the piping or traps allowing fumes back into the living space.

I've heard that a good way of checking location of this type of leak is to wipe with a damp rag, and then get up into the fresh air away from the smell you're trying to fix, then sniff the rag.

Is it a vented tank, and if so is there a charcoal filter - is that OK?

[bazjude2998]

Thanks for your reply.The tank is vented but no charcoal filter.The problem has only appeared this last year after 20yrs constant use.In the scheme of things I suppose not bad.I just feel that a deep clean would help.All the obvious have been checked,I am really asking on advice of what would be the best chemical to use.The Agent Orange of the Sh-t tanks.Thanks

[Jonesy23]

Bio washing powder / liquid and water may work. It's supposed to work as an alternative to 'blue' anyway.

Otherwise good old bleach and water fill might do it but might ruin seals. Assuming a bad seal isn't the problem to start with.

[Muncher]

The line cleaner I use to clean beer lines with each week is very good at dissolving organic material. Years ago when I worked at my local pub, if anyone ever blocked a toilet with an enormous turd the landlord just poured line cleaner down there and it totally dissolved it.

[Tuna]

My immediate reaction is to check that the ventilation hasn't changed. The more you stifle decomposition, the more it is likely to build up nasty smells. Usually these things have to find a balance, rather than specifically being 'clean'. Too much bleach and other chemical cleaners can cause as many problems as anything.

[Squiggs]

bazjude2998 said:

....... we add chemical Blue at the advised amount (apparently too much will kill the good bacteria as well as the bad ) .....

I don't buy this theory .......

When you add blu at the prescribed amount the dosage is for a full tank - but you add it to an empty tank.
So as soon as you put it in the strength is way above what it should be until it's 'watered down' by added waste.
I'm sure the manufacturers of Blu have your 'apparent' problem covered.

Most motorhomes/camper vans have a tank for the loo and another for 'grey' (dirty sink) water.

In our motorhome our blu treated 'loo' waste (whilst not smelling of roses) doesn't smell that much.
I think Blu copes quite well with 'natural bodily' waste.

But I've never heard of 'grey' water being treated with Blu (or anything else!)

I might be talking a load of twaddle - but I don't think Blu can deal with with, soap, detergent, cooking fat, etc,etc in the same way it copes with 'natural' loo waste.
Our (untreated) grey water tank seems to ferment and can quickly stink something rotten (especially in warmer weather) - and therefore we dump it regularly. (If there is a treatment for grey water I'd love to hear about it)

If my theories are correct .....
Does your loo waste and grey water go into the same tank?
If so could it be that your grey water is neutralising the effect of Blu?????????


In answer to your original question - I've heard things about bicarb of soda, soda crystals and even steredent being used to clean tanks.

It might be worth you asking on some motorhome forums.

[bazjude2998]

Thanks for all replies.In this instant the holding tank is solely sewage,rightly or wrongly all grey water is discharged into the canal system,some interesting chemical suggestions

[SiH]

I assume there must be some access into the tank, even if it's not enough to get a typical jet washer lance inside it. I've got one of these for cleaning out our drains at home and it's really good. Do you think you could get this into the tank via the drain or other access?
http://www.espares.co.uk/product/es547362?utm_sour...

[bazjude2998]

Thanks Si ,Karcher kit my do the trick but as always nothing easy (that makes life interesting)The tank is L shaped quite large in area but shallow.I suppose we all look for the easy fix in this case it would be great to fill the tank with chemical/ water mix,leave for a couple of weeks drain down,question is what's the best chem to use.

[Tuna]

Tuna said:

My immediate reaction is to check that the ventilation hasn't changed. The more you stifle decomposition, the more it is likely to build up nasty smells. Usually these things have to find a balance, rather than specifically being 'clean'. Too much bleach and other chemical cleaners can cause as many problems as anything.

BTW, I say this as we have a whole house sewage tank that 'self digests' - it has no moving parts and discharges to the neighbouring fields. We've had it nearly a decade and it rarely smells. The trick is that it has a decent airflow over the contents, which allows aerobic bacteria to do their stuff. The stuff that smells is usually anaerobic (think - stuff that's been trapped in a container to go off).

Cleaning and sealing will not encourage aerobic bacteria - you'll just get the same smells coming back again.