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.

Thanks