Neutral to alkaline conditions are optimal for denitrification.
As the pH increases above 9.0, the accumulation of
nitrite increases significantly (24). Thus, control of the pH
of groundwater during biodenitrification is important because
microbial activity can result in pH changes and heterotrophic
denitrification in particular may increase the pH.
Several methods, such as reagent addition and use of encapsulated
buffer (25), have been used for pH regulation.