Influence of pH control on material characteristics, bacterial community composition and BNR performance of mature aerobic granules

•Effects of pH control on properties and performance of mature granules were studied.•pH ≤ 7.0 significantly reduced EPS and size of the granules and increased flocs.•pH ≤ 7.0 inhibited nitrification and reduced P removal efficiency of the granules.•Without any significant impact on granules’ properties, pH ≤ 7.5 improved P removal.•pH control altered bacterial community structure of the granules after two months.