STP Log Book

[everdecreasingcircle]

Hi we have just got a permit for our stp, can anyone show me their log book for how to record samples, and how often etc.  Also to talk me through what they do to keep a check on things.  Thank you.

[SteamyTea]

I cannot help at all.

 

What is the STP?

 

 

[dpmiller]

is the requirement for a treatment plant log book- and ongoing sampling-  not a German/ mainland European thing?

[joe90]

36 minutes ago, SteamyTea said:

I cannot help at all.

 

What is the STP?

 

sewerage treatment plant 

 

[SteamyTea]

27 minutes ago, joe90 said:

sewerage treatment plant

Right, and that needs a log book.

Is that for installation or usage, or even both?

[joe90]

I saw no requirement to have a log book when I installed mine, just advised to have an annual check.

[Temp]

Google finds..

https://www.scribd.com/document/376182521/Log-Book-for-Operation-ETP

 

But is it required in UK?

Edited June 20, 2023 by Temp

[everdecreasingcircle]

Thank you, we have a permit and i thought we had to check it and log the water quality, maybe i have mis understood

[Crunchynut]

I have a permit too. You need a permit if you can’t meet all of the binding rules - in my case my discharge is to a ditch which is seasonally dry and hence I need a permit. As you say, permit requires maintenance by a suitably competent person but it doesn’t clarify what this means. Also building regs requires home owner to appraise new owners of what it takes to run the STP when house is sold - but I bet that never happens.

 

To comply with my permit obligations I record (using a cheap go pro type device) a video of me checking the tank once every couple of months. So, just video evidence that the aeration is working, effluent is clear, ditch is clear etc. I also do a settlement test which consists of taking a 2 litre sample and recording the % by which it settles every 5 minutes for 30 minutes. Basically you would expect it to settle down to around 30 or 50% in 30mins. This shows that the tank is operating properly and doesn’t need emptying. If it only settles to 90% then it may need emptying. I can share details on this if you are interested.

 

I then just store my videos on my computer and if ever I am asked for evidence by EA then I have it. I have never been asked though.
 

I wouldn’t pay anyone to do this - they will just charge you a couple of hundred quid for nowt.
 

[everdecreasingcircle]

Hi Crunchynut

 

Thats Brilliant, thank you.  Yes please all the advice we can get is much appreciated 😊.

[Crunchynut]

So, first of all, if you read my thread on here: 

 

https://forum.buildhub.org.uk/topic/32308-the-science-behind-sewage-treatment-plants/

 

you will see my general cynicism about the subject - that rules are put in place but there seems little or no real understanding or follow up. By chance I had a tradesman round my house recently who showed an interest in my stp because he said he used to work for a ‘maintenance’ company, but he gave up the job because he felt bad charging people for just cleaning off the greb and not doing any real maintenance or science based assessment. He said I was right to do it myself. 
 

So, I think it pays to understand how your plant works, know when it’s working correctly and when it isn’t, and what to do about it. Doing this, I think you will be much better placed to convince any EA inspector that you are in control.

 

Now - the settlement test - it’s quite simple but tells you quite a lot. The way STPs work is that the muck/ bacteria soup forms a ‘floc’ that sticks together and will settle in still water. Then the clear effluent runs off the top. If this floc isn’t forming well then either it won’t settle or it won’t form in the first place. In either scenario there is no clear effluent to be had and hence it’s a problem. All sorts of factors can affect whether your floc forms nicely - the amount of oxygen in the water, the type of bacteria growing which is linked to what’s entering your tank etc etc.

 

For the settlement test you just need a tall scientific beaker. There is a company on the web that sells ‘settleometers’ for a couple of hundred quid (!) but I found a company on the web that sold chemistry equipment to schools and got a tall 2 litre flask/beaker for about £20 delivered. All I did then was run some masking tape up the side and marked off 10% increments. You also need some kind of paddle to gently stir the effluent after you have filled the flask to the 2L mark, and use the paddle to bring the mixture to a standstill before removing it.

 

You then start a timer and write down the %level that the effluent settles to every 5 minutes, for 30 minutes, with a final one at 60 mins. You can also record the clarity of the effluent too. See my pics.

 

What you are looking for is ideally for settlement to be quite quick to begin with - perhaps down to 70% or so in 5 minutes, then it will start to slow down but should be around 30-50% after 30 mins. 

My tank went through a tricky period where it was only settling to 90% and I very nearly got it pumped out, but I figured my aeration wasn’t right and adjusted it, and after 5 months it has recovered to give a 30 minute settlement of 52% without having been pumped out - which shows if you understand these things then you can save yourself some money.

 

If you are a real nerd (like me) then you can plot the settlement curves and have a whole series of them by date - proving that your stp is consistently performing well.

 

Anyway - enough for know, but just ask if you want to know more.

Edited June 22, 2023 by Crunchynut

[everdecreasingcircle]

Thank you so much for taking the time to share your knowledge.  We will have a good read up on everything.   Its so hard to find good adivce, yours is much appreciated.

[Crunchynut]

You are welcome. I see you have a vortex 10. I have a Vortex 6 so we are in the same territory.