sewage treatment

[acresswell]

Anyone willing to share their wisdom/experiences of sewage treatment?

We're demolishing an old house and rebuilding.  The old house has a concrete septic tank which needs to be replaced by something better.
Our neighbour is connected to the mains sewer, but they're about 100 metres away. 

Keen to hear thoughts on the options? Have I missed any possible options?

A) plant with air bubbler?
   - using electricity
   + only 1 moving part
   + cheapest to purchase
  -  needs most frequent emptying

B) plant with rotating discs?  e.g. Klargester Biodisc
   - using electricity
   - lots of moving parts
  -  needs frequent emptying
   
C) Biorock, which claims to use a chimney effect to aerate the treatment chamber
   + no electricity needed
   - needs a separate settlement tank
   ? does it really work
   - install seems to be tricky to get right
  + claims that settlement tank only needs emptying every 2-3 years
  ? claims very high effectiveness
 
D) Conder Clereflo Eco, which uses coconut husk that is then composted after 10 years
  + no electricity needed
  -  will coconut husk still be available to replace in 10 /20/30 years time?
  - will a disposal route for the ‘used’ coconut husk still be available in 10/20/30years time?
  ? Claims that settlement tank only needs emptying every 1-3 years

e) Have road dug up and connect to main sewer
  + long term low maintenance/ lack of hassle
  - up-front cost
  - disruption to road & neighbours

I've ruled out reed beds due to lack of space. The site slopes significantly, so space is really tight on the downhill side of the house and still quite tight on the uphill side. There’s just about be space on the downhill side for a drainage field and a “unit” of some description. We don’t need to drive over it, but once the building work is done it'll be pretty difficult to get a replacement unit into place if it fails!

She Who Must Be Obeyed (or at least consulted) has definitely ruled out composting toilets ...and even if I succeeded in changing her mind (not sure I want to try!) we’d still need some waste water treatment.  We’ll be using rainwater where possible (big tank going under patio), with top-ups from the well if we’re still allowed to do so, so I’d be reluctant to fit a complex system to process grey water until it’s clean enough for re-use.  We’ve got mains drinking water and electricity.

Thanks in advance,

Adrian

[billi]

Hi

Is the old tank broken ?

Why not think of constructed wetland  (reed bed idea )  , if you have some space for it

[Ev]

We have a Klargester Biodisc BC for our sewage treatment and our neighbour's - we've had it for 13 years now.  We have a maintenance contract that covers a yearly once over, call outs for faults, and replacement parts.  That comes to approx. £200 per year split between the two properties.  The tank gets emptied once a year with no problems with solids build up.  The only real fault that we've had with it was with the belt drive slipping off and/or breaking so this has now been replaced with a chain drive.  I think it's rated at 50W but I see that the website rates them at a bit higher - maybe that's for newer ones.  They are very quiet with no smells unless the disc stops turning when the belt snaps or there is a power cut for a long period of time (days).  It feeds into a soakaway which has a sort of overflow to a wee burn in case the water table gets too high to cope (as per SEPA's instructions).

[billt]

If you have enough suitable land for a good leach field, a properly designed and installed septic tank is the best solution.

However, if you are only 100m from mains drainage I'd connect to that and it's likely that the LA/EA will insist on it.

[Ted]

At our previous place we had a Klargester Biodisc installed to replace a septic tank. We had continual problems with the drive belt coming off until the service company did a major service on it, which seemed to fix it. I've no experience of the chain drive replacement that Ev mentions.

Here we installed an Acorn system with air compressor and a pumped output system for the holiday accommodation block about 5 years ago. We have had to replace the pump once - at a cost of around £200.

My advice is get a system that requires zero electricity usage.

[Justme]

  The tank gets emptied once a year with no problems with solids build up. 

What does the emptying cost.

[Ev]

It's about £150 with Scottish Water.

[biff]

the latest news here this morning,
                        the powers that be are in the process of organising and sending septic tank inspectors our way, each inspection will cost in the region of 2 to 300euros and every tank had to have a yearly inspection. dont you get the idea they are short of money,
                                                        biff

[acresswell]

Thanks for the thoughts so far...

Billi, Afraid there isn’t space for a reedbed on either side of the house... and especially not on the side where the existing tank is. 
We need to replace the existing tank because it doesn’t clean up the effluent sufficiently.  We might have got away with using it if we were modifying the existing house, but as it’s a complete rebuild we’ve got to put in a solution that meets the modern standards.

Ev, thanks for the info (and especially the prices).  Your feedback agrees with the other Klargester owners that I’ve come across (generally pleased but with occasional mechanical issues)

Billt,  I must admit that I’d prefer to be connected to mains drainage,  but I’m wary of the cost of digging up the road.  I’ve just had a look at the CON29DW search we had done when we bought the house and it is 140m from the house to the nearest sewer.  Anyone got any experience of costs, etc?  Although it’s not a massively busy road (one of 4 ways in/out of the village) it would cause disruption to various neighbours (and it’d be about a 6 mile diversion for the farmer who trundles up and down regularly from the farm to most of his fields).  There are no footpaths, and the road is pretty narrow so I reckon the whole thing would have to be closed rather than just putting up traffic lights.  The new drain couldn’t run across the fields because it would then have to flow uphill for much of its length (or the trench would be about 6-8m deep in places!) and would also make a big mess of a patch of protected woodland!

Ted, I agree with you about the electricity-free system... but I’d also like reassurance that they work in practice before going that route, because once the system is in it won’t be easy to get a big enough digger in to replace it!

anyone out there with experience of C or D?


Thanks

[BruceB]

As I said in another thread, I did not like the idea of all the external mechanical gubbins in a Klargester, so installed a Biodigester instead which has air pumped through it to do the aeration/agitation.  I am happy with it.
Regards
Bruce

[titan]

Thanks for the thoughts so far...

We need to replace the existing tank because it doesn’t clean up the effluent sufficiently.  We might have got away with using it if we were modifying the existing house, but as it’s a complete rebuild we’ve got to put in a solution that meets the modern standards.

Provided you have acceptable percolation a septic tank meets the regs, if fact the BRE's two papers on off mains treatment say overall it is the best solution. You will need to do percolation tests whatever system you choose so it may be worth doing them before making a final decision. I did a little application which when fed the required data  for the standard test gives the leach field sizes, I used it for my ( new build) site. If you would like a copy just say.. The regs are online and always worth reading rather than getting  a packaged treatment plan manufacturer's interpretation of them.

[Ted]

Provided you have acceptable percolation a septic tank meets the regs, if fact the BRE's two papers on off mains treatment say overall it is the best solution. You will need to do percolation tests whatever system you choose so it may be worth doing them before making a final decision. ...

Is that the current case?  I thought that it was acceptable for clean water from a sewage treatment plant to discharge directly to a watercourse. It certainly was a few years ago.

(fixed the broken quote in your post so that I could then quote you correctly)

[titan]

Provided you have acceptable percolation a septic tank meets the regs, if fact the BRE's two papers on off mains treatment say overall it is the best solution. You will need to do percolation tests whatever system you choose so it may be worth doing them before making a final decision. ...

Is that the current case?  I thought that it was acceptable for clean water from a sewage treatment plant to discharge directly to a watercourse. It certainly was a few years ago.

(fixed the broken quote in your post so that I could then quote you correctly)

Not sure what you mean, If you are discharging into a water course why would you need percolation tests  although you  will  need written consent to discharge.   If the discharge from a treatment plant is not into a watercourse but the ground, you still will need acceptable percolation test results.  The latest regs are here www.planningportal.gov.uk/buildingregulations/approveddocuments/parth/approved     septic  tanks are fine.

[dhaslam]

You will probably find that the farmer doesn't need to access his land, at least with equipment,   in the winter and the other residients should be able to leave their cars at the end of the road for a few days.    If you can get a big contractor to do it with a few machines working together it shouldn't take too long.    In Ireland the Council have to finish the road off which can be expensive.   

[billt]

It looks like diggerjohn is a representative of a company that sells Biorock treatment plants. He's just posted a similar (unsubstantiated) claim about reed beds freezing on the green building forum.