Septic tanks

[RogerS]

We have a brick built septic tank and yours truly thought that they never needed emptying. Cesspits Yes - Septic tanks - No. Now I realise the error of my ways as the secondary tank has filled up with crud..partly decomposed leaves (yup..the cover rotted away)..partly due to you-no-what from the main tank. So it needs looking at. I had the main tank sucked out today but the man with the machine shook his head when he saw the secondary tank. 'That'll all need to come out'..he said.

Researching google hasn't thrown up anything like ours. The secondary tank appears to have been constructed with crushed stone in the bottom, covered by sheets of corrugated asbestos (and there's another worry but we won't go there). This has all been filled up with mud and muck. I dug out most of the stuff down to the level of the corrugated sheets but a quick looksie at the stone shows it to be filled up with crud as well.

I have a horrible feeling that it all has to come out, the tank itself be hosed down and then refilled with clean stone etc. Quite what the outflow to the soakaway will look like I shudder to think. Reckon that that will be blocked up as well.

Doom and gloom.

Any clues..?? And stop laughing at the back there

 

[CHJ]

Never seen one constructed like that Roger.

Ours, and all other in this area as far as I know has two 'wet tanks' brick construction and some 6+ft cube each.

First one, is main receptacle and holds the bulk effluent, the second holds runoff fluid from first tank and provides settlement of residual solids before discharging waste water to soak away.

The one we had in bedfordshire was similarly constructed, although soakaway was non existent there due to local clay and it behaved more like a cesspit.

IMO the asbestos sheet is not a problem as it will be cement bonded and no risk of dust whilst wet.

Sounds like it was used as a separator to enable a muck out 'like wot you have done'.

 

[Steve Maskery]

Never mind Roger, you won't smell anything 'cos of theDanish Oil...

I know nothing about this subject, but that doesn't stop me cotributing, you see?

Cheers
Steve, who once buuilt a septic tank in a desert village in Mexico. I had spent 4 evenings at nightschool brick laying class, and, in Mexico, that made me Master Builder!

 

[Jake]

The crushed stone is presumably intended to hold anaerobic bacteria?

If so, it wasn't ever going to be clean down there.

French supermarkets sell packets of bacteria to top 'fosses' - my parents have had great success in reducing the frequency of emptyings with regular dosings of that.

That said, I have no idea what you need to do!

 

[wrightclan]

The crushed stone is presumably intended to hold anaerobic bacteria?

If so, it wasn't ever going to be clean down there.

French supermarkets sell packets of bacteria to top 'fosses' - my parents have had great success in reducing the frequency of emptyings with regular dosings of that.

That said, I have no idea what you need to do!

Don't know if a top-up of bacteria/enzymes will solve your particular problem, but it is a good idea to top up periodically, as household chemicals, etc. will degrade the level of bacteria and enzymes. I buy some stuff at B&Q that keeps my two old brick tanks ticking over just fine (once I reinstated the soakaway that the previous owner had removed. ](*,) But that's a story for another thread perhaps...) I have a Canadian friend who swears by beef liver tossed into the tank annually. :shock: Presumably the beef liver contains the requisite bacteria and enzymes.

Brad

 

[dedee]

I can remember working with a mate up in Cumbria who thought it would be a good idea to dump a load of rubble in the, long since, unused septic tank in his garden. We took off the cover but could not see much and there was little or no smell. So there we were each holding one end of a large lump of concrete over this manhole. We both let go simultaneously then peered down to see where the concrete went.

Yep you guessed it a split second later we were covered in it! Still didn't smell though :lol: It was shortly after Xmas and was then forced to have a cold "shower" under the garden hose. His missus did not want us in the house for some reason.

Sorry if that doesn't help - hope it made you smile.

Andy

 

[A_n_g_e_l_a]

It might be a lot easier to get a Klargester here

Angela

 

[Jake]

Don't they cost about £10k to install, though?

 

[A_n_g_e_l_a]

I seem to remember £3k for four properties - but that was a while ago.

Angela

 

[Losos]

Roger - It's probably far too late for the 'bacteria' stuff, but I can say that when you'vr got the thing back to normal a monthly dose of the 'bacteria' stuff will keep it clean.

Ours looks like a packet of soup and we just pour it into one of the toilets. Works a treat.

 

[wrightclan]

I've been thinking a bit more about this one. The muck in the bottom should not need to be removed, as long as you are getting good flow into the secondary tank (from the primary tank) and good flow out from the secondary tank (and the outflow pipe needs to be a good bit above the muck filled stone.)

Testing the inflow should be no problem. Not sure how you would test the outflow though? :-k

Brad

 

[RogerS]

I've been thinking a bit more about this one. The muck in the bottom should not need to be removed, as long as you are getting good flow into the secondary tank (from the primary tank) and good flow out from the secondary tank (and the outflow pipe needs to be a good bit above the muck filled stone.)

Testing the inflow should be no problem. Not sure how you would test the outflow though? :-k

Brad

I've yet to find the outflow pipe :?

 

[wrightclan]

I've been thinking a bit more about this one. The muck in the bottom should not need to be removed, as long as you are getting good flow into the secondary tank (from the primary tank) and good flow out from the secondary tank (and the outflow pipe needs to be a good bit above the muck filled stone.)

Testing the inflow should be no problem. Not sure how you would test the outflow though? :-k

Brad

I've yet to find the outflow pipe :?

Hmmm, makes me wonder if the crushed stone is an attempt at a soakaway? Maybe something like this?
(Look at the bit down the page on 'seepage pit.')

Is the inflow pipe visible, and how high is it above the stone?

Brad

 

[RogerS]

Sorry if I misled you, Brad. I do know for a fact that there is an outflow pipe. Just that I've not uncovered it due to all the crud. I reckon that the tank design must be circa 30 - 40 years old. No sign of the vent pipes as per your diagram. Still if I can get it cleaned out it will last us until we move I reckon!

 

[wrightclan]

Roger,

If that's the case, you're probably right. Just make sure you get good inflow and outflow, and you should be fine. Mine doesn't have vent pipes either.

Brad

P.S. Certainly not a job I would relish. :roll: :? Good Luck.

 

[A_n_g_e_l_a]

I seem to remember that changes to a septic tank mean the Environmental Health people have to come and check the outflow after things have settled down. Best make sure you are not spending time and money on something which will fail an EH check. Or am I being a sceptic? :?

Angela

 

[RogerS]

I seem to remember that changes to a sceptic tank mean the Environmental Health people have to come and check the outflow after things have settled down. Best make sure you are not spending time and money on something which will fail an EH check. Or am I being a sceptic? :?

Angela

Only if you're rebuilding one or putting in a new one. Otherwise they'd need a team of hundreds. There are estimated 800,000 septic tanks in the Uk!

 

[OLD]

I have a filter system for my pond fish which after the initial filtering allows the water to flow over a multi tubular media which is designed to have a large surface area in a relatively small space the water flows over/through this and bacteria clinging to it cleans it up .
This seems to be working on the same principals as your secondary chamber it provides extra cleaning to pretreated water flowing through it. So if its cleaned up to say 'grubby' to have some seed bacteria and the plumbing is checked so as to maintain a level of water in the chamber at all times (refill it) i would then expect the output water to go to a soak away system.
I have reread your post and now think you have a under gravel ( used in fish tanks) system where water flows up through gravel with of course bacteria to clean the water

 

[RogerS]

A picture's worth a thousand words and should have done this at the beginning.

is the final tank. Water enters via the pipe at the top and then drops down onto a bit of guttering (removed at the moment) where it then drops down onto the corrugated asbestos.

shows the pipe end and just beneath a broken bit of asbestos to the right of the picture, the stones that are all blocked up solid. The ivy is not growing there :wink:

At the bottom of the stones (probably 3 ft deep maybe?) is the outlet into the soakaway in the field. I reckon that I need to expose the outlet pipe and check to see how blocked up it is, clean if possible then backfill with clean stone.

 

[OLD]

So its like the circular beds at the sewage works with a static water delivery, new stone should have it good as new and the action will build up over time should be trouble free for a number of years.