What should be the pH range in the wastewater treatment plant for proper biological function?

The optimal pH for the function of activated sludge is 7, i.e., neutral. However, the biocenosis of the activated sludge can adapt within a pH range of about 6-8, provided that it is stable and does not fluctuate. In the case of fluctuations, it will be a problem to keep the biology at the WWTP in a functional state. It is then necessary to deal with the neutralisation of the wastewater before its actual treatment at the WWTP.