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High TVCs in water samples

water TVC microbiology

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#1 sarahw

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Posted 17 December 2018 - 02:39 PM

Hi everyone

 

I'm hoping that someone can provide me with a flash of inspiration!  

I am getting high TVC (out of spec) results at 22°C and 37°C from water samples, the high results have all come from handwash sinks with mixer taps.

The taps are clean, the water temperature coming out of the taps is >35°C, the water pressure is good.

There is a water storage tank but I have had this purged and treated a couple of months ago and the issue went away.

I'm at a bit of a loss; has anyone had similar issues?

 

Many thanks  :)



#2 Scampi

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Posted 17 December 2018 - 02:44 PM

Do you have fine mesh filters on the taps used to aerate the water?  When was the last time the faucet was dissembled?  You may have organics built up on the faucet causing your high numbers


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#3 Charles.C

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Posted 17 December 2018 - 03:34 PM

Hi everyone

 

I'm hoping that someone can provide me with a flash of inspiration!  

I am getting high TVC (out of spec) results at 22°C and 37°C from water samples, the high results have all come from handwash sinks with mixer taps.

The taps are clean, the water temperature coming out of the taps is >35°C, the water pressure is good.

There is a water storage tank but I have had this purged and treated a couple of months ago and the issue went away.

I'm at a bit of a loss; has anyone had similar issues?

 

Many thanks  :)

 

Hi sarah,

 

Could you quantify what you mean by "high" ?

 

Is this an internal lab ?

 

As per previous post you may need to sample prior to the tap.


Kind Regards,

 

Charles.C


#4 sarahw

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Posted 17 December 2018 - 03:38 PM

It's an external lab whose results I do trust.  Counts range from 60 to >301.

Taps are looking clean and yes, we did take them apart and clean the parts we could get to.

I will double check again though.

It's really frustrating!

Thank you for your help.



#5 QAGB

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Posted 17 December 2018 - 03:39 PM

Hi everyone

 

I'm hoping that someone can provide me with a flash of inspiration!  

I am getting high TVC (out of spec) results at 22°C and 37°C from water samples, the high results have all come from handwash sinks with mixer taps.

The taps are clean, the water temperature coming out of the taps is >35°C, the water pressure is good.

There is a water storage tank but I have had this purged and treated a couple of months ago and the issue went away.

I'm at a bit of a loss; has anyone had similar issues?

 

Many thanks  :)

 

This sounds a lot like an issue we have experienced this year. I would suggest you disassemble the faucets and sanitize them (as Scampi said), and then re-test them. If that doesn't work, you need to trace your lines backwards to the storage tank(s). What is the next common area that has a tap? Test that water as well. Keep working backwards until you find the source of your issue. We eventually found the source of our issue, and have mostly resolved the problem, but not 100% yet. You may need to look at investing some money into (more -- if you don't already have) UV lights on inlet/outlet points.The link to the thread I started is below. Maybe this will help.

 

https://www.ifsqn.co...-water-testing/


Edited by QAGB, 17 December 2018 - 03:40 PM.


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#6 sarahw

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Posted 17 December 2018 - 03:49 PM

Thank you Scampi, Charles C and QAGB  :smile:  we're going to do this tomorrow.  There is a map of the water system so it should be easy to trace back.  I'll have a look at your link too and let you know how we get on!


Edited by sarahw, 17 December 2018 - 03:54 PM.


#7 trubertq

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Posted 17 December 2018 - 03:56 PM

Is it possible the sample was contaminated? Did you let the tap run for a few minutes before you took the sample?


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#8 sarahw

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Posted 17 December 2018 - 03:59 PM

Hi Trubertq - yes, the water was left to run for a good minute :/



#9 Charles.C

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Posted 17 December 2018 - 04:11 PM

Hi Sarah,

 

i forgot to ask what yr usual APC levels are like ?

 

is there a measurable residual chlorine level (eg DPD)? (obligatory in UK I think). If so  APC should be quite low IMO. (IIRC the UK limits are not quite the same as EC)


Kind Regards,

 

Charles.C


#10 sarahw

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Posted 18 December 2018 - 11:03 AM

Hi Charles C - they are usually <10 and <100.  I will have a look at residual chlorine level too, thank you.






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