Installing new septic tank (klargester) - Barn conversion needs new sewage system

[jad]

Hi, new to the site -and new to drainage - ever wish you had never started? I am converting an old barn and have embarked on the major task of installing the sewage sytem for it. The local building control chap has become a very close friend in the last few days as I have toiled with a 105 m ditch and the realisation that water will not flow up hill!
Basic problem is to do with levels and gradients. We are on clay and the dischage is into a pond (owned by me!) which is 100 m from the building - I have worked back from the pond (starting well above (150mm) the high water level to a sewage treatment plant 60 meters upstream. I have only achieved a gradient of approx 1:150 and although I have successfully tested it - (bucket of water down the pipe appears at the pond end) I am worried that this is not enough gradient? The answer I guess is to lift the treatment plant a bit higher but this will reduce the gradient from the house to the treatment plant which is now 1:40 - just! The distance from the house to the treatment plant (Klargetser biodisk) is 45 meters and a fall of 48 inches has been measered with a laser thingy.

My dilema is that if I raise the treatment plant I will gain more gradient on the section to the pond (treated waste water), but lose gradient on the section between the tank and the house (raw sewage etc - nasty business!). Also it looks like I need to bury the sewage pipe under at least 150mm of concrete at the house which means it will be at least 200mm underground as it leaves the building - is there a min depth allowable or can I raise the pipe as high as I can get it?

Any thoughts?

???

[lutonlagerlout]

did the architect not sort all this out at the design stage?? this is like bread and butter for people who build 1 off houses in rural locations.
when i have installed these theres is usually the tank quite near the house (acess for the sewage lorry" then the pipe is buried in gravel ,i dont recall a lot of fall being necessary for this pipe as i thought the water that comes out is fairly clean
if you are that worried why not just build a great big septic tank but then that has to be emptied more regular than the klargester.
also you could try and recycle waste water that is not foul i.e. bath,washing machine water etc.
regards tony

[jad]

In theory everything is nicely drawn on a piece of paper but that is not really very helpful at present. A spetic tank is not an option and the Klargester has to be sited 45 m from the house. The water that exits the Klargetser is very clean and I am hoping that a modest gradient will suffice. Your coments regarding recycling are interesting.

[lutonlagerlout]

45 m why so far?
thinking about it if it is just water then no fall at all is needed as water will run to an outlet on a legth of pipe
i know this because i always put guttering up level, as the water once it gets to a couple of mm must go down the pipe
i am sure we did a drain for a farmer in eaton bray and we only had 9" over 200 ft
when i say recycle bathwater i meant more for irrigation than actual recycling
regards tony

[Suggers]

In exactly same situation as you - apart from, we're in chalk, (hooray) - Luton Lager speaks sense - surrounded the Klargester in pea-shingle - sited about 100 metres from house with access - the whole point is that the Klargester lower outlet is virtually water, spread out in a herring-bone pipe system - however - we built a serious motherf**ker soakaway -
PM me for details......
ps - the fall to the Klarg is the mostimportant....

[Suggers]

Sincere "peeeps who live on clay"
We feel for you.

[jad]

The Klargester has to be 45m away because the building control chap says so! I know its ridiculous but he insists on 25m from any habitable (potentially) building and there is a barn between us and gravity!

Suggers - Hi - thanks for your comments - what gradient did you manage to achieve into the tank? I believe 1:80 is acceptable as long as a WC is connected - 1:40 otherwise - dont understand why seems to me that "solid stuff" would need more gradient? Also how did you set out the drain pipes over such a long distance - string, laser level??? I presume you laid on pea shingle?

[Suggers]

Will checkout Klarg fall tomorrow -
Sending the liquid outflow to a pond sounds weird.....
ps - pea-shingle? - yep.
pps - string & spirit level.

[seanandruby]

if it falls too fast the liquid goes and leaves the sh, er, effluent behind and builds up eventually. what is gonna be covering pipes? if they are too shallow then should be concrete surround for protection. about 450 below after that shingle will do.

[lutonlagerlout]

yeah i never really understood why they want soil pipes to be such a low fall ,but as sean correctly states the thinking behind it is that the whole mass will move as one.
also if they are too steep when they hit a IC the sh*t etc tends to splatter which over a period can cause blockages
as long as its roddable and you have rodding eyes where theres any bends you should be ok
we use a theodolite for anything over 5 metres
and in the past have used a 25 m water level on site for fairview homes. setting up datums for dpc
best regards tony

[jad]

Thanks everyone - that has been really usefull - I feel much more confident that the system will work!
Suggers - the outfal into a pond is allowed because the water is virtually clean by the time it leaves the Klargester thing.

Just got all the pipes in and it has pi**ed it down - hoping to God they do not float!!!!!!!

Den