WEF Discussion Forums
Operation and Maintenance
pH of Mixed Liquor
We're having problems with nitrification in an enclosed HPOX aeration unit with surface aerators. The pH is probably borderline at 6.2-6.3. It is probably depressed by CO2 buildup in the headspace of the UNOX. My research indicates we would get minimal nitrification at that pH.
I'd like to know what normal pH is in mixed liquor from other types of aeration processes. Please tell me your pH and type of aeration.
I have several types of aeration system none of which use
pure oxygen. Our pH is between 6.5 and 7.5 at all times. I would guess the
reason for your depressed pH is a lack of alkalinity or over nitrification, if there
is such a thing, or a combination of the two. I would decrease the aeration
rates and monitor alkalinity, ammonia and nitrate at the end of the aeration