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Checklist In Preparation: Off Mains Drainage


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#1 recoveringacademic

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Posted 11 February 2016 - 08:37 AM

Thought I'd start from the 'bottom up' as it were. I intend to work on this as normal thread so that the list is seen -and critiqued- by as many people as possible. There is is little point in a checklist that has not been validated by peer review. All comments are very welcome. The more we get, the better the list.

It'll take about a week or 10 days to pull the greater part of the relevant content together. Until then, treat this list as a work-in-progress

Off Mains Drainage

Edited by recoveringacademic, 12 March 2016 - 06:46 AM.


#2 declan52

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Posted 11 February 2016 - 02:24 PM

How do you intend to discharge the waste will influence what method you pick. Septic tank and treatment plant plus a drainage area if its going into the ground. Has to be a treatment plant if its going into a stream.
The water table height will have a big impact on how you work your levels out esp the winter height. If you install your system too low the soakaway will fill up during the winter and won't work and will leech out into your garden and that's just nasty.
Soakaway can't be deep, no more than around 500-600mm. Has to be in the aerobic soil layer. Effluent needs this oxygen to treat it by soil bacteria.
Don't be shy with concrete around your tank or plant, you don't want it bobbing about like a buoy.
With a treatment plant the main problems arise when you flush stuff you shouldn't. Anti bacterial products, bleach, milk and toliet fresheners all kill the bacteria in the plant.

#3 recoveringacademic

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Posted 11 February 2016 - 03:43 PM

View Postdeclan52, on 11 February 2016 - 02:24 PM, said:

How do you intend to discharge the waste will influence what method you pick. Septic tank and treatment plant plus a drainage area if its going into the ground. Has to be a treatment plant if its going into a stream.
The water table height will have a big impact on how you work your levels out esp the winter height. If you install your system too low the soakaway will fill up during the winter and won't work and will leech out into your garden and that's just nasty.
Soakaway can't be deep, no more than around 500-600mm. Has to be in the aerobic soil layer. Effluent needs this oxygen to treat it by soil bacteria.
Don't be shy with concrete around your tank or plant, you don't want it bobbing about like a buoy.
With a treatment plant the main problems arise when you flush stuff you shouldn't. Anti bacterial products, bleach, milk and toliet fresheners all kill the bacteria in the plant.

Now, there ya go..... I had no idea that milk and toilet freshener b@ll@cked up a treatment plant. I'll have to stop having milk with my tea. Damn.

#4 PeterStarck

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Posted 11 February 2016 - 03:43 PM

My old septic tank went into a leachfield, which is where the bacteria did their work. My new treatment plant flows into a reedbed system and then into a simple soakaway. I could have got away with not needing the reedbed or soakaway if I had a suitable ditch or stream.

#5 recoveringacademic

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Posted 11 February 2016 - 03:47 PM

View PostPeterStarck, on 11 February 2016 - 03:43 PM, said:

[...] My new treatment plant flows into a reedbed system and then into a simple soakaway.[...]

Peter, I'm discharging to a stream, but the idea of a reed-bed attracts me. How have you sorted your reed bed out? We've got a fairly good, consistent fall over the site... about 2 meters or so I'd like to see if I can build a reed-bed into the flow.

Got to keep our Great Crested Newts amused somehow eh?

#6 PeterStarck

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Posted 11 February 2016 - 04:07 PM

Ian, I'm not trying to put you off my type of reed bed system, well I am I guess, they are hard work if you don't really need one. If you use the recommended reeds they grow 8' high and the whole bed needs clearing out and replanted every 4 years. I soon got fed up with cutting the reeds down regularly and replaced them with water irises which do the same job but less vigorously and with flowers. The system I've got is a Klargester Reedbed System which consists of two 2.5m x 0.8m tanks which are 0.8m deep and buried in the ground with the tank top level with the surrounding earth. That is enough for up to 6 people. There are natural reed beds that you can build yourself and that your newts would love! They are much more interesting than mine if you have the space. There's a reasonable amount of info ont web about constructing that type.

#7 declan52

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Posted 11 February 2016 - 04:12 PM

View Postrecoveringacademic, on 11 February 2016 - 03:43 PM, said:



Now, there ya go..... I had no idea that milk and toilet freshener b@ll@cked up a treatment plant. I'll have to stop having milk with my tea. Damn.
Any thing that you use in the house to kill bacteria can't go down the system into the treatment plant or it slowly kills of the bacteria and then you just have a big plastic holding tank full of raw sewage.
Milk reduces the amount of oxygen in the tank.
Found this online for the do`s and dont`s.
http://www.wte-ltd.c...o_and_dont.html

#8 recoveringacademic

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Posted 11 February 2016 - 04:33 PM

View PostPeterStarck, on 11 February 2016 - 04:07 PM, said:

Ian, I'm not trying to put you off my type of reed bed system, well I am I guess, they are hard work if you don't really need one. If you use the recommended reeds they grow 8' high and the whole bed needs clearing out and replanted every 4 years. I soon got fed up with cutting the reeds down regularly and replaced them with water irises which do the same job but less vigorously and with flowers. The system I've got is a Klargester Reedbed System which consists of two 2.5m x 0.8m tanks which are 0.8m deep and buried in the ground with the tank top level with the surrounding earth. That is enough for up to 6 people. There are natural reed beds that you can build yourself and that your newts would love! They are much more interesting than mine if you have the space. There's a reasonable amount of info ont web about constructing that type.

Excellent. That's what I'll do.

Gonna open a Great Crested Newt Theme Park. It'll be good to know that they are processing our waste.

#9 recoveringacademic

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Posted 12 February 2016 - 09:57 AM

View Postdeclan52, on 11 February 2016 - 04:12 PM, said:

Any thing that you use in the house to kill bacteria can't go down the system into the treatment plant or it slowly kills of the bacteria and then you just have a big plastic holding tank full of raw sewage.
Milk reduces the amount of oxygen in the tank.
Found this online for the do`s and dont`s.
http://www.wte-ltd.c...o_and_dont.html

Declan, that's a valuable link. If I can find some way of validating it ; say some .gov.uk or .gov.ie site or maybe even an .ac.uk (academic) site to validate what this company says, the we can turn that list into a useful reference for ebuilders.
Thanks for your effort. I appreciate it.
Ian

#10 PeterW

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Posted 12 February 2016 - 11:08 AM

Ian

That list is from a number of sources - there are a few copied from WPL and the like. The use of "kill" is a little overrated as unless you get the chlorine or bleach concentrates into the parts per thousand you're not going to destroy the bacterial build up....

I've also got a similar list from Kl&r****er who I would never recommend to anyone however their list is very good !

Key points are about using chemicals, and that most are now marked with "Septic Safe" or similar words - the Ecover brand is very good, as are the commercial ones from Environmental Supplies.

AFAIK the EA don't produce a list although each manufacturer has their own guidelines. Also worth talking to an independent such as MPC Services who install and maintain all the different brands.


Actually a quick google found this :

http://www.knollands...stems-guide.pdf

Its from British Water and has a disclaimer that EA etc don't endorse products but a skim read and its pretty comprehensive

Edited by PeterW, 12 February 2016 - 11:13 AM.


#11 ferdinand

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Posted 12 February 2016 - 12:23 PM

Not my subject but would be useful to have something in about:

* Approximate areas likely to be needed for each approach, so people can quickly get at whether they have space to avoid wasting time on "not possibles".
* Soil types and how little you can get away with having - thinking of Jeremy's use of his little bit of permeable soil in his not-very-permeable plot.

Do we need to distinguish between "drainage" and "sewage treatment" in this?

Ferdinand

Edited by ferdinand, 12 February 2016 - 12:24 PM.


#12 recoveringacademic

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Posted 12 February 2016 - 12:51 PM

Thanks for the replies.
This area is a mine-field, but I think I can use the government guidance as a framework on which to hang the main points.

The key to adding value through an ebuild checklist is that the points made should be validated in some way. Preferably by ebuilders themselves telling us about their experience. And it's the discussion which follows which allows other readers to judge its relevance and usefulness.
Without validation, the checklist becomes just another list. That's why it's important for me to link the list item to the originating thread.

I am not the authority. You all are. My role is simply to do a bit of interesting leg-work, and then to encourage you to prod me when I miss something.

Right, off to sell my Land Rover so I can buy my digger :huh: . Still agonising over JCB (Back Hoe, Front Bucket) or tracked 2.6 tonne Kubota.
Have a good weekend if you get one!
Ian

#13 ProDave

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Posted 12 February 2016 - 05:09 PM

View Postferdinand, on 12 February 2016 - 12:23 PM, said:

Not my subject but would be useful to have something in about:

* Approximate areas likely to be needed for each approach, so people can quickly get at whether they have space to avoid wasting time on "not possibles".
* Soil types and how little you can get away with having - thinking of Jeremy's use of his little bit of permeable soil in his not-very-permeable plot.

Do we need to distinguish between "drainage" and "sewage treatment" in this?

Ferdinand
Re size, it's building regs that set the size of a soakaway based on the occupancy of the house (number of people BR thinks it can house, not the actual number living there) and the percolation rate of the ground. this is something you have no choice over.

If you choose a treatment plant instead of a septic tank, you can reduce the size of the soakaway by about 20%

Remember it's not just the size of a soakaway you need to allow for. It's the clearance distances as well. No part of the treatment plant or soakaway can be less than 5 metres from a building, 5 metres from a boundary, 10 metres from a road and 10 metres from a watercourse.

That's why the entire side garden of our house, all 15 metres of it, is "allocated" to the treatment plant and a small partial soakaway.

If buying a plot that has PP for a house and a treatment plant, check that the site really is big enough to fit it all in, it can take a considerable amount of space;

#14 stones

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Posted 12 February 2016 - 07:21 PM

This may seem a very basic point, but there is sometimes the impression that certain foul water treatment systems are complete solutions, omitting the fact that treated discharge still has to be disposed of, be it to watercourse or soak-away. Some reed bed systems and a couple of others seem to be guilty of this. If you have never experienced off mains drainage, this one could catch you out, especially at the plot buying stage (as per the comments above about having sufficient space).

#15 ProDave

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Posted 12 February 2016 - 07:34 PM

To further reinforce my point. Before I bought my plot, I researched the drainage issue. SEPA then told me I could not discharge to the burn. I came up with a filter mound drainage system that appeared to satisfy SEPA and fit on the plot, so I proceeded and got full PP.

Then came the building warrant and that was refused because they did not accept the drainage system. Building regs had changed and the clearance distances had increased and my system no longer fitted.

There then followed several weeks of anxiety at which point we had PP to build a house but no building warrant so we could not build it. It was only solved by a change of heart by SEPA who granted us permission to discharge to the burn.

This illustrates it's perfectly possible to have PP to build a house that you can't actually build.

#16 Crofter

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Posted 13 February 2016 - 11:54 PM

One of the differnces between Scotland and other parts of the UK is the distances between the elements involved (house, boundary, watercourses)- we are allowed to have the system within 5m of the house but I believe in England (and possibly other parts of the UK) it has to be further away. I think the boundary distance in England is only 2m, up here it is 5m. Sorry I don't have references to hand for all of that.

A 'partial soakaway' (sometimes referred to as a 'seasonal soakaway') can be used as an intermediate step between discahrge to ground and discharge to watercourse, in cases where the flow in the watercourse is marginal and at risk of drying up. Essentially an undersized, open ended, soakaway is constructed with the expectation that in dry weather it will cope with the flow, whilst in wet weather it may overflow into the watercourse which will at that time have adequate dilution. I discussed this method with both my BCO and SEPA, although no hard and fast rules or formulae were applied at any stage (e.g. on dilution rates, or sizing the soakaway area). My impression is that a partial soakaway will only be accepted if the effluent being discharged is already treated (so not just coming from a septic tank)- in my case it is coming from a Puraflo peat fibre filtration system.

Hope that helps

#17 mafaldina

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Posted 14 February 2016 - 05:40 PM

Has anyone had any experience of the ClearFox system? The German site claims you can reuse the water as grey water.

#18 joiner

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Posted 14 February 2016 - 05:49 PM

See also...

http://www.ebuild.co...eed-bed-issues/