Bertie29

Septic Tank needs to be changed

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I have a septic tank on the property that looks as though it was built with the house in the 1920's and I have to change it. I am in a dilemma about what to change it to as I have no experience in this area whatsoever. I have had several quotes and each person seems to be telling me something different!! I am looking at a Bio Pure which is the cheapest option (by £2k!!) and the Klargester Biotec 1 and the Solido Smart which are about the same price. The overflow at present runs into a ditch which is mainly dry during the summer months. I did think about resituating the tank but I was told it would come under different rules as I am not using the pre-existing outlet. Has anyone got any experience or information in this field as I do not want to make the wrong decision and find later on that I can't sell the property because I have not got the correct paperwork or tank.

 

Any help would be greatly appreciated.

 

 

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what size/ shape is the current chamber? How many PE do you need as a replacement? We went for a Solido Smart but I don't know how anything could be £2k cheaper...

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We have a Bio Pure that drains into the stream across the lane from us.  Seems to work very well, no smells, reliable, just need to factor in servicing the air pump every three or four years.  We have a spare air pump (takes about ten minutes to swap them over) so can just swap them and then service the other one (takes an hour or so to fit a new diaphragm kit and clean the air filter).  A servicing kit for the air pump is around £20 IIRC.

 

The regs say that a treatment plant must not drain into a ditch that is dry for part of the year, but I'm pretty sure this doesn't really cause a problem in practice, and anyway the regs have said that about septic tanks for decades, so you're not changing anything for the worse.  The effluent from a treatment plant is massively cleaner and less harmful than the effluent from a septic tank, as a septic tank doesn't treat the effluent and discharges stuff with a very high biological oxygen demand (which is what kills fish etc if the stuff get's into watercourses). 

 

As far as paperwork goes, as you're just replacing an existing installation with a newer and higher spec one, I'd have said that there shouldn't really be any issues.  I'm not even sure that it needs to be notified to building control, as a "like for like" replacement that's a significant improvement to what you already have.

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ALL septic tanks draining to a watercourse need to be changed to a treatment plant by the end of 2019.  I am surprised there is not more publicity about this. 

 

Whatever you do, don't buy a treatment plant that has moving mechanical parts down in the smelly stuff. Trust me, you won't want to be the one changing the motor or belt WHEN it goes wrong.

 

Instead choose one that works with an air blower.  There are several now to choose from such as the Biopure, Conder, Graff, Vortex and no doubt many others.  The air blower type do also seem to have the best / cleanest effluent of all treatment plants.

 

I paid just under £2K for my conder, which looks very similar in design to the BioPure.

 

In Scotland you would need a building warrant to install the new treatment plant, I don't know if that is needed in other parts of the UK.

 

At least one member on here has a treatment plant draining to a dry ditch and building control were happy with it. 

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4 minutes ago, ProDave said:

Whatever you do, don't buy a treatment plant that has moving mechanical parts down in the smelly stuff. Trust me, you won't want to be the one changing the motor or belt WHEN it goes wrong.

 

shitty tips from @ProDave :)

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1 hour ago, dpmiller said:

what size/ shape is the current chamber? How many PE do you need as a replacement? We went for a Solido Smart but I don't know how anything could be £2k cheaper...

 

The current one is holds about 2,000 litres, it was a shared cesspit originally. It has 3 chambers in total but the overflow smellys pretty bad. I just need one that is big enough to cater for a maximum of 6/7 people. The difference in cost I assume is in the groundwork not the price of the tank which is why I wondered why there was such a difference in the price, but if the Bio Pure is going to do the job then I guess that will be good enough (hopefully!!)

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1 hour ago, Moonshine said:

 

shitty tips from @ProDave :)

Thank you very much, I will bear that in mind, I certainly don't want to be fixing something in that area!!

 

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1 hour ago, JSHarris said:

We have a Bio Pure that drains into the stream across the lane from us.  Seems to work very well, no smells, reliable, just need to factor in servicing the air pump every three or four years.  We have a spare air pump (takes about ten minutes to swap them over) so can just swap them and then service the other one (takes an hour or so to fit a new diaphragm kit and clean the air filter).  A servicing kit for the air pump is around £20 IIRC.

 

The regs say that a treatment plant must not drain into a ditch that is dry for part of the year, but I'm pretty sure this doesn't really cause a problem in practice, and anyway the regs have said that about septic tanks for decades, so you're not changing anything for the worse.  The effluent from a treatment plant is massively cleaner and less harmful than the effluent from a septic tank, as a septic tank doesn't treat the effluent and discharges stuff with a very high biological oxygen demand (which is what kills fish etc if the stuff get's into watercourses). 

 

As far as paperwork goes, as you're just replacing an existing installation with a newer and higher spec one, I'd have said that there shouldn't really be any issues.  I'm not even sure that it needs to be notified to building control, as a "like for like" replacement that's a significant improvement to what you already have.

Thanks, I feel like I am entering a mindfield, a very smelly one too!! I just want to get it right from the beginning, but thank you for your advice, very helpful.

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22 minutes ago, Bertie29 said:

[...]

 I have had several quotes and each person seems to be telling me something different!!

[...]

 

So far, so normal.

23 minutes ago, Bertie29 said:

[...]

I do not want to make the wrong decision and find later on that I can't sell the property because I have not got the correct paperwork or tank.

[...]

 

In changing from a septic tank to a digester - which everyone should have done by the end of this lunar year, you will be upgrading the system to produce significantly less BOD (Bio-chemical Oxygen Demand) on the local stream. Virtually nobody is taking a blind bit of notice - certainly nobody in West Lancs could either care  less , I bet 99% of residents dont even know about it. Fewer still would  care.

 

The advice issued by the relevant authorities says you don't need to inform them (I'll look up the reference if needed) if all you are doing is to continue discharging to the same stream. If you are planning to discharge significantly more effluent than previously, (say you are increasing the number of houses on site)  then you may need to tell them.  But frankly, my advice is, proceed in good faith, improve the quality of the discharge. 

 

Here is the official guidance

Wonder why I sound cynical? Here's the answer.

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What are your ground conditions?  You will need to be digging a 2 metre or deeper hole to install it.  Will you be likely to hit rock?  Will the hole fill with water due to a high water table?  These might influence which one you fit, and HOW you fit it, i.e it may need to be concreted in if a high water table.

 

This is what you want to be discussing with your supplier / installer. If he just comes back and says "I always fit this one" ask him why and what is so good about it.

 

There are a few other options if you have a bedrock problem and can't dig deep.

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1 hour ago, ProDave said:

What are your ground conditions?  You will need to be digging a 2 metre or deeper hole to install it.  Will you be likely to hit rock?  Will the hole fill with water due to a high water table?  These might influence which one you fit, and HOW you fit it, i.e it may need to be concreted in if a high water table.

 

This is what you want to be discussing with your supplier / installer. If he just comes back and says "I always fit this one" ask him why and what is so good about it.

 

There are a few other options if you have a bedrock problem and can't did deep.

I don't think I have a high water table, we are pure clay here which is horrendous when it comes to digging anything, it's either rock hard or as soft as marshmallow and gets everywhere but I have never hit rock before. The only thing is that I seem to get a bit of movement between winter and summer when the clay shrinks and expands which has caused me a few issues. The hole will fill with water if it rains as the clay tends to hold onto it when the hole is dug but once it is backfilled it should be fine, but I did wonder about concreting it in because of this. I have asked the supplier these questions but they all seem to think that theirs is the best!

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I would concrete it. We once fitted a plastic tank in clay in dry conditions. Concrete base and just backfilled with shingle.  The following year after it had rained a lot the sides and base were misshapen.  The tank was plenty oversized so we filled the bottom of the tank with concrete to prevent if from collapsing but I would concrete all round if I had my time again.

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We're on clay, too, and have a fairly high water table.  The hole for our treatment plant filled with water overnight and had to be pumped out before we could install it.  We bedded ours in concrete, to help hold it down, and after about 5 years it still seems fine.

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3 minutes ago, Bertie29 said:

[...] I have asked the supplier these questions but they all seem to think that theirs is the best!

 

Not helpful is it.... but par for the course.  Here's what to do;

  • Work out the fall from your final discharge to the winter  water table . Dont know what the water table level is? Dig a hole and watch what happens in various weather conditions : it varies widely here.
  • Dig the hole for the tank
  • Most tanks (from all suppliers I bet) have little lugs on the side which are designed to give  concrete something to hold onto.
  • Pop the tank in the hole.
  • Backfill with concrete to a level higher than the lugs on the  tank
  • If necessary install ground anchors (complex name for a simple device: some bits of metal chained to the side of the tank)
  • If you like install a ground drain round the tank such that it tends to keep the groundwater low near the tank (I did this because I'm anal)
  • backfill with shingle (round shingle) and MOT1 22mm to fines
  • Connect the supply and discharge side of the tank as per regs.

Is the cheque in the post yet?

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2 hours ago, AnonymousBosch said:

 

Not helpful is it.... but par for the course.  Here's what to do;

  • Work out the fall from your final discharge to the winter  water table . Dont know what the water table level is? Dig a hole and watch what happens in various weather conditions : it varies widely here.
  • Dig the hole for the tank
  • Most tanks (from all suppliers I bet) have little lugs on the side which are designed to give  concrete something to hold onto.
  • Pop the tank in the hole.
  • Backfill with concrete to a level higher than the lugs on the  tank
  • If necessary install ground anchors (complex name for a simple device: some bits of metal chained to the side of the tank)
  • If you like install a ground drain round the tank such that it tends to keep the groundwater low near the tank (I did this because I'm anal)
  • backfill with shingle (round shingle) and MOT1 22mm to fines
  • Connect the supply and discharge side of the tank as per regs.

Is the cheque in the post yet?

Unfortunately I can't afford to send you a cheque (got to spend my money on changing the tank!!) but I still thank you for you advice.

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3 hours ago, JSHarris said:

The regs say that a treatment plant must not drain into a ditch that is dry for part of the year, 

 

Thats not strictly true, I have installed a  Vortex and that can discharge to a ditch that is dry part of the year, it was passed by the environment agency. I got a good price from  https://www.wte-ltd.co.uk/vortex_sewage_treatment_plant.html. Only stipulation on the part dry ditch is the installation of a rumble drain (the pipe from plant to ditch is full of holes and is bedded in drainage stone). We are also on clay (hence no drainage field) and have a high water table. The tank needed full concrete backfill because of the water table.

  • Like 1

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1 hour ago, joe90 said:

 

Only stipulation on the part dry ditch is the installation of a rumble drain (the pipe from plant to ditch is full of holes and is bedded in drainage stone). We are also on clay (hence no drainage field) and have a high water table. The tank needed full concrete backfill because of the water table.

I had that same stipulation from SEPA when they granted my permit to discharge into our burn.

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No such stipulation here in NI, and our site is in an AONB with the outflow passing by local streams into an ASSI

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When I talked to SEPA about it they said it was their policy to require a rumbling drain on all such plants as a backup, even though the output of the plant should in principle be clean enough.

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8 minutes ago, Ed Davies said:

When I talked to SEPA about it they said it was their policy to require a rumbling drain on all such plants as a backup, even though the output of the plant should in principle be clean enough.

They described it to me as a "partial soakaway"  but the stupid thing was this partial soakaway must meet all the normal restrictions for a soakaway, including it must be >10M from a watercourse.

 

So I had to go back from being perforated pipe to solid pipe for the last 10 metres, where of course whatever is left runs out into the burn.

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What they wanted from me was a rumbling drain, ideally at least 50 metres long, though a bit shorter would probably be alright. Mine will actually be around 60 metres so they were quite happy with that. I guess if it was a lot shorter (to be practical in the area of your plot) then the rules would be a bit different. Still, they'd want something between the plant and the burn which might not be required in other countries in the UK.

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Bio Pure here, concreted-in due to high water table. It's been running for a year 'in anger', discharging into a dyke, and seems ok (ie no smells, and most importantly, no cause for me to take the lid off).

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