Pure and Ultrapure - water guidelines

[Ian Wilde]

Hello all, below is an excerpt from the 2016 guidelines:

2.2 Setting the design specification for the water treatment infrastructure

Guideline 2.2.1 – Specification of the maximum allowable limits for microbiological contaminants
in water produced in new water treatment systems

We recommend that all new water treatment infrastructures when used with a rigorous proactive
sanitisation strategy should be capable of producing water with microbial and endotoxin concentrations
of < 0.1CFU/mL and < 0.03EU/mL, respectively. (1D)

Note: Dialysis fluid of this quality is often referred to as “standard” dialysis fluid, and it
undergoes further treatment at the patient’s bedside to meet “ultrapure” dialysis fluid
requirements.

The figures quoted as <0.1 and <0.03 are ultra pure ones as far as I understand?

The Note added in the guidelines reads as though it needs to go through further processing to make it ultra pure. Am I missing something or do others agree?

Also, should the terms of Dialysis Fluid and Dialysis Water not be separated to avoid confusion?

Ian

[Roger Moore]

I would read 'at the patient's bedside' to mean ultrafilters?

[Ian Wilde]

I would too Roger, however the water quality it quotes is ultra pure already isn't it before it is treated at the bedside?

[fraser gilmour]

I agree Ian, I think it's a mistake in the edit. The note shouldn't be there at all as the section relates to water for dialysis, not end product dialysis fluid
I also think it's ambiguous to say "new water treatment infrastructures", does this mean new at the point of commissioning, i.e. only during the validation stage it should  be able to produce water meeting this quality? or new as in modern water treatment equipment. I think it should be the latter as we know well designed modern systems can regularly meet this standard.  

[Ian Wilde]

But then also we have to make sure your version of modern is the same version that I think of

Words like "new" and "modern" are open to an individual's interpretation and we should try to avoid them when writing these kind of documents - but that's just my own opinion.

[fraser gilmour]

Exactly, I think the authors intentions were to encourage a move towards RO permeate water feeding dialysis machines meeting "ultrapure" standard, rather than relying on point of use filtration within the machines, it's just worded a bit clumsily.
There will be an opportunity to correct this when the document is revised for the new ISO 23500 series, i'll pass on to Nic Hoenich.    

[Ian Wilde]