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janatherton  
#1 Posted : 07 December 2020 16:37:26(UTC)
Rank: New forum user
janatherton

I have a process water tank at ambient temps which contains phosphate solution at a dilution of 15litres in 1000litrs water (from SDS this contains orthophospheric acid 1-10%, phosphated phenol ethoxylate 1-10% and ammonium biflourode 1-10%).   Does anyone know if this would inhibit legionella growth or if I'm going to need to test it?   

Many thanks

Roundtuit  
#2 Posted : 07 December 2020 19:23:26(UTC)
Rank: Super forum user
Roundtuit

Any time you add a control measure you need to determine its efficacy - not as a "one off" but an on-going determination. Every decent water treatment supplier will recommend a routine testing regime to determine when, and how much control is required. No different for legionella- the system will loose volume and will require "topping up"
Roundtuit  
#3 Posted : 07 December 2020 19:23:26(UTC)
Rank: Super forum user
Roundtuit

Any time you add a control measure you need to determine its efficacy - not as a "one off" but an on-going determination. Every decent water treatment supplier will recommend a routine testing regime to determine when, and how much control is required. No different for legionella- the system will loose volume and will require "topping up"
A Kurdziel  
#4 Posted : 08 December 2020 10:57:58(UTC)
Rank: Super forum user
A Kurdziel

I think the issue Jana has is that the tank is one that normally contains this phosphate solution for some sort of  process,  and she wants to know if the solution will support the growth of legionella or not. My answer is I don’t know but things she can consider include; is there a risk of an aerosol being produced which people might breath in, is the tank kept clean so that there is no build up of biofilm in the tank  and  how static is the water in the tank. I am assuming the temperature is in the range that supports legionella growth. That said the only way to be certain is to get the water tested.

Kim Hedges  
#5 Posted : 09 December 2020 15:29:39(UTC)
Rank: Super forum user
Kim Hedges

OK, that's a good question, does this chemical suspension allow legionella to grow, or as I suspect (but have no evidence to prove it either way), it's probably the same as adding bleach - it kills legionella.  I worked for a short time in a factory that dipped metal sheets into a similar product prior to powder painting, so I understand the question a bit. 

I would say to ask a chemist to test it first off, yes the tank may be topped up automatically with fresh water, due mostly to normal evaporation, but the solution would still be sufficient to kill any bacterial growth. 

The water that feeds the tank would in theory be part of the normal fresh water system and should already be under pre planned maintenance to prevent legionella. Check with your maintenance people or person as it's often one man who does everything.  

janatherton  
#6 Posted : 17 December 2020 14:54:55(UTC)
Rank: New forum user
janatherton

Thanks everyone - yes its for a preparation process sprayed onto the workpiece hence the question due to aerosol.  Staff wear RPE in the vicinity however if I can eliminate the legionella risk it's one less issue to think about...  I'll introduce some dipslides into the process monitoring and see what turns up.

Roundtuit  
#7 Posted : 17 December 2020 15:50:14(UTC)
Rank: Super forum user
Roundtuit

DIP slides are used to check control mmeasures are functioning and usually just denote a Total Aerobic count.

Identification of the presence of Legionella should be conducted by a laboratory with suitable and sufficient controls along with the correct growth media and techniques.

Roundtuit  
#8 Posted : 17 December 2020 15:50:14(UTC)
Rank: Super forum user
Roundtuit

DIP slides are used to check control mmeasures are functioning and usually just denote a Total Aerobic count.

Identification of the presence of Legionella should be conducted by a laboratory with suitable and sufficient controls along with the correct growth media and techniques.

A Kurdziel  
#9 Posted : 17 December 2020 16:32:05(UTC)
Rank: Super forum user
A Kurdziel

I think that this is the standard method 

BS EN ISO 11731:2017

Water quality. Enumeration of Legionella

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