Septic tank - should it be smelly?

[Lindyboo]

Our septic tank is an old brick type and has been housed for many years inside a tatty corrugated iron garage, used only as a log-store. There are no windows in the back of the garage so plenty of air gets in, but the tank has always had a strong odour of sewage requiring the doors to be left open for a few minutes before spending any time in the garage. The tank gets emptied every couple of years.

I’ve always assumed it’s normal to have such an odour, especially as the tank is housed in the albeit draughty garage which will prevent some escape, but recently someone told me it’s not normal for a septic tank to have any odour at all.

I’d welcome board members thoughts on this. Thanks.

 

[FamilyWiggs]

Are you sure it is a septic tank and not a cess pit?

A septic tank shouldn't need emptying; it works on bacterial action which digest the waste and you should have fairly clean water run off via a soakaway. Emptying it will get rid of the nice waste-digesting bacteria.

A cess pit I understand, is a big hole full of, well you know what; this will require emptying.

We have had septic tanks in a number of properties and have never emptied them. Sometimes they smell, especially close up and in summer. Occasionally they benefit from reseeding with bacteria. A rotten leg of lamb chucked in or, (and don't tell DEFRA and I'd never do this as it is technically illegal 8) ) some dead stock if you have lost a lamb or some chooks will also reseed the tank.

http://en.wikipedia.org/wiki/Septic_tank

 

[vicky whitworth]

Well, I'd never thought of that. Since our septic tank is inside our chicken run we could simply lift up the manhole cover and push them in :roll:

Our septic tank tends to smell some of the time, and there's little logic to when it does and when it doesn't although perhaps if the weather is particularly still it's more inclined to smelly so maybe that's similar to being inside a garage. Ours is a septic tank but we have it emptied every few years, and the man who empties it says we should do it every year. As you know it's blocked at the moment and we didn't manage to persuade same man to come out this week and unblock it, so chooks have had to have a section of the run cordoned off or they'd be wading through poo

Husband had electric fence for Christmas so, actually, hens are now moved elsewhere in the garden during the day. Cat isn't too keen on fence after his first shock.

 

[Lindyboo]

Hello. Yes, definitely a septic tank. I'm interested to note your comment that tanks should never need emptying, because that's what I thought. Before we moved here I researched the subject and the general consensus seemed to be leave it alone. Couldn't persuade my other half of this so therefore it gets emptied.

I'm trying to find out if the odour can be remedied as we're planning a major garden overhaul and erection of a new garage. The old garage housing the tank is quite an eyesore and may well fall down if not demolished, which would expose the tank and allow the pong to drift over the garden (it's about 50ft away from the house). Also under consideration is an extension which would take the dwelling nearer to site of the tank so the odour would be more of an issue.

Are there any 'over the counter' products which might eliminate the odour?

It's been suggested that a tall vent might remedy this (we have no near neighbours who would be inconvenienced by such).

Thanks

 

[Penners]

Are you sure it is a septic tank and not a cess pit?

A septic tank shouldn't need emptying

Well, yes - that's the theory. But I've yet to come across a septic tank that doesn't need emptying from time to time - particularly given that the bacterial action is highly likely to be compromised by the chemicals that most of us use these days - toilet cleaners, washing up liquid, dishwasher and washing detergents, shampoos, shower gels, handwash, floor cleaners... and so on. I bet there are very few people who can honestly say that nothing like that ever gets into their tank.

Our septic tank needs emptying once a year - and it is a septic tank, not a cesspit.

Lindyboo - the smell is probably quite normal, but you may be able to reduce it. Where is the vent for the tank? It should have one. If this is inside the garage, it will obviously exacerbate the stink. And are there any access manholes inside the garage? They could have the same effect, particularly if they don't seat very well.

To reduce the smell, you could (a) pipe the vent through the wall of the garage so that it's outside, and (b) generously grease the underside rim of any manhole covers inside the garage, so that they seal well on the groove where they seat. I can't promise that this will be a total solution, but it should help.

Other than that, you'll just have to hold a lace handkerchief sprayed with Chanel No 5 to your nose, when you collect the logs. :wink:

 

[Lindyboo]

Thank you Penners. I don't think there is a vent in the garage and I suspect that the pong gets out through the manhole cover which sits atop the tank without any evident seal. I'll have to investigate - with Chanel at hand as you suggest.

Cheers

 

[FamilyWiggs]

How do you know when your tank needs emptying Penners? What does emptying annually achieve? The thing should be pretty full most of the time.

Chemicals can harm the bugs, but we are careful generally and have no problems - most products are septic tank friendly these days (including dishwasher detergent) and our cleaning regime is not fastidious enough to include things like bleach! There are over the counter solutions you can buy to assist the bugs, but are probably just a reseed colony like a ripe piece of meat would have...

I really can't think of a problem or benefit that would warrant annual emptying of a functioning septic tank. In over ten years of having different tanks I've never done it or needed to.

I suppose that over time there is indigestible solid matter that will gradually fill the tank from the bottom up... But unless you flush a lot of lady products into a small tank and have significant bowel problems, it must take more than a year to fill. :shock:

Unless of course the benefit is maintaining full employment for septic-tank emptying firms! :wink:

What does it cost to have it emptied and reseeded?

 

[JoceAndChris]

Ours hasn't been emptied in 200 years!! I don't know whether it's a cess pit, septic tank or soakaway but it's been described by the previous owner as a stone chamber. It doesn't smell and it's fine. Undoubtedly the hilltop location and the enormous trees growing from its, um, nutrients, help.

Hope the OP gets this sorted, it doesn't sound good. And so very pleased to read Vicky has an electric fence.

 

[vicky whitworth]

Thank you Jose. Chooks are less pleased - lots of squarking when they touch it and they are too thick to remember that before they tough it the next time. But they do like being in a different part of the garden.

Really interesting about the septic tank. I can't understand why it would need emptying but that was what we were told - not that we did it, but then when it over-flowed the man told us off for not having had emptied regularly. I wish we could work out how to unblock it this time but we can't get the drain rods to reach where we think the block is - it's more an inspection point rather than a roding point. We can't bend the drain rods at 90 degrees. Any bright ideas?

 

[robgil]

I always thought that the heavy smelly stuff sank to the bottom while a layer of clean water remained at the top sealing the smelly stuff below?

 

[robgil]

Thank you Jose. Chooks are less pleased - lots of squarking when they touch it and they are too thick to remember that before they tough it the next time. But they do like being in a different part of the garden.

Really interesting about the septic tank. I can't understand why it would need emptying but that was what we were told - not that we did it, but then when it over-flowed the man told us off for not having had emptied regularly. I wish we could work out how to unblock it this time but we can't get the drain rods to reach where we think the block is - it's more an inspection point rather than a roding point. We can't bend the drain rods at 90 degrees. Any bright ideas?

Try a hose pipe. :wink:

 

[Baron de Gynes]

... and stand well back!

 

[FamilyWiggs]

Yes, a hose pipe should do it Vicky. Use it like a drain rod, and have some water flowing through it. Or try rodding backwards from below the blockage?

A septic tank should be full all the time - to the level of the outflow pipe, where clean water should overflow into your soak away or leach pipe work. If the exit pipes from the septic tank get blocked then it will overflow. This might be what happened previously?

 

[MdB]

I can't say I'm an expert on poo pits but I remember reading that the idea of a septic tank is that the solids are in the first chamber, the liquid from which moves in the second chamber before exiting to the soak away. If solids move to the second chamber, they can then travel into the soakaway potentially silting it up which stops it from working, leaving you with an expensive and smelly problem to deal with.

If the bacteria can break down everything that are sent into the first chamber into liquids then there isn't an issue with emptying. If they can't then it will need to be periodically emptied. I've no idea which is generally the case.

I would be interested in an unbiased opinion from someone expert (i.e. not somebody that empties pits as a trade) as to what the real situation is.

 

[Lime]

How do you know when your tank needs emptying Penners? What does emptying annually achieve? The thing should be pretty full most of the time.

Chemicals can harm the bugs, but we are careful generally and have no problems - most products are septic tank friendly these days (including dishwasher detergent) and our cleaning regime is not fastidious enough to include things like bleach! There are over the counter solutions you can buy to assist the bugs, but are probably just a reseed colony like a ripe piece of meat would have...

I really can't think of a problem or benefit that would warrant annual emptying of a functioning septic tank. In over ten years of having different tanks I've never done it or needed to.

I suppose that over time there is indigestible solid matter that will gradually fill the tank from the bottom up... But unless you flush a lot of lady products into a small tank and have significant bowel problems, it must take more than a year to fill. :shock:

Unless of course the benefit is maintaining full employment for septic-tank emptying firms! :wink:

What does it cost to have it emptied and reseeded?

We've had this discussion before about emptying septic tanks.
IME they never need emptying, but I've always had a large system and never flushed damaging chemicals down into it.
The majority of the content is human excrement and all of it is completely biodegradable.
There are no human solids that cannot be consumed by bacteria.
The design of the tank demands that air can access the first tank and no air at all can access the second.
Solids are broken up and consumed by aerobic bacteria and other larger organisms in the first vented tank then slowly fed into a another tank/section where different anaerobic bateria consume everything else in an oxygen depleted environment.
The liquor that flows off should be clear and clean with little or no smell whatsoever.
Human excrement is stuffed full of bacteria of both sorts required so no seeding of the tank is neccessary in reality.

The only smelly area should be from the first tank and that can/should be vented via pipes to the outside of the garage.
The lids or covers should be completely sealed to passage of air and water into the tanks.

 

[FamilyWiggs]

MdB and Lime - thanks, and that seems to have been my experience too. Hopefully it is helpful to the OP.

 

[Lindyboo]

Thanks all for your valuable input; it's highlighted a few points that I hadn't considered. I'll investigate the venting situation and take that into account when planning the garden/garage work.

Cheers

 

[worms]

I always thought that the heavy smelly stuff sank to the bottom while a layer of clean water remained at the top sealing the smelly stuff below?

I thought there should be a crust of floating material on the first chamber which also helps reduce the smell. In my limited experience of having a septic tank, there is a very marked difference in smell between a properly functioning tank and one which has ceased functioning and essentially become a cess pit.

 

[Lime]

I thought there should be a crust of floating material on the first chamber which also helps reduce the smell. In my limited experience of having a septic tank, there is a very marked difference in smell between a properly functioning tank and one which has ceased functioning and essentially become a cess pit.

I concur with that.

 

[Penners]

How do you know when your tank needs emptying Penners? What does emptying annually achieve? The thing should be pretty full most of the time.

Chemicals can harm the bugs, but we are careful generally and have no problems - most products are septic tank friendly these days (including dishwasher detergent) and our cleaning regime is not fastidious enough to include things like bleach! There are over the counter solutions you can buy to assist the bugs, but are probably just a reseed colony like a ripe piece of meat would have...

I really can't think of a problem or benefit that would warrant annual emptying of a functioning septic tank. In over ten years of having different tanks I've never done it or needed to.

What does it cost to have it emptied and reseeded?

If you visited us a year or so after our last emptying, FW, you would quickly recognise that the tank needs emptying! On a warm summer's day, the aroma can be fairly rich. And if we fail to empty it, after 18 months or so the foul water pipes from the house start to back up.

As for chemicals, our septic tank emptying chappie (he is actually a local farmer whom we know - he does this as a sideline) says that septic tank friendly products are a bit better than the rest, but he knows lots of people who use them religiously, and they still need their tanks emptied periodically.

It costs us £90 for an empty. Still a hell of a lot cheaper than the annual charge for mains drainage. So frankly we're fairly happy to carry on with the system we've got - perfect or not. As for reseeding, we seem to manage that ourselves, on a daily basis! :x