1 reply to this topic

[Shanasi]

Hi,

 

I am an intern in a waste water treatment company. I have been given a task to review existing pH adjustment calculation prior to treatment. I find the calculation might not be accurate as there is no consideration of alkalinity of waste water in it assuming waste water should have higher alkalinity.

 

Example of scenario is pH adjustment of waste water from pH range of 6 to pH 11 using NaOH (48%).

 

The question now is, should I consider the alkalinity when calculating the chemical dosing, and if yes, how would be the calculation steps be (references, if any)?

 

Thank you.

 

 

[fseipel]

If you are titrating with NaOH, the alkalanity will not enter into the picture, because you are simply measuring how much titrant is required to bring the pH to the desired endpoint value -- regardless of buffer concentrations.  If you are only measuring the pH, and correlating to titrant required, then yes, the buffering impact of alkalinity may matter if it's high and varying between when correlating table was built and current values.  If dosing is to a continuous stream, then this may be more an issue of loop tuning.