I am trying to impliment some pH control logic on a wastewater treatment system.
We are useing 93% sulfuric acid and 57% magnesium hydroxide as the adjusting agents, delivered by pumps controled by VFDs.
First stage is coarse adjustment of the pH in a 80,000 US gallon tank, the acid or base is added inline on a recirculation path that feeds the contents back into the tank.
From there the contents can go to a 8,000 US gallon 2nd stage tank for fine adjustment. Acid or base in added directly into the tank at this point.
Both tanks have agitators.
The wastewater will vary in content and compositon, and I don't have any titration curve data for the system. I don't want to use a PID loop, but I am unsure of what kind of deadtime to expect with the amount of wastewater in the tanks and neutralizing agents that are being used (I am familliar with the chemistry, but lack actual experience implementing pH control).
Also, I am unsure of how to calculate reasonable dosing amounts. I am told there are lookup tables for this, but since the wastewater will vary is this approach still valid? Or should I calculate an average dosing amount myself?
Any suggestions? I appreciate the help.
Thanks.
We are useing 93% sulfuric acid and 57% magnesium hydroxide as the adjusting agents, delivered by pumps controled by VFDs.
First stage is coarse adjustment of the pH in a 80,000 US gallon tank, the acid or base is added inline on a recirculation path that feeds the contents back into the tank.
From there the contents can go to a 8,000 US gallon 2nd stage tank for fine adjustment. Acid or base in added directly into the tank at this point.
Both tanks have agitators.
The wastewater will vary in content and compositon, and I don't have any titration curve data for the system. I don't want to use a PID loop, but I am unsure of what kind of deadtime to expect with the amount of wastewater in the tanks and neutralizing agents that are being used (I am familliar with the chemistry, but lack actual experience implementing pH control).
Also, I am unsure of how to calculate reasonable dosing amounts. I am told there are lookup tables for this, but since the wastewater will vary is this approach still valid? Or should I calculate an average dosing amount myself?
Any suggestions? I appreciate the help.
Thanks.