Performance of heterotrophic partial denitrification under feast-famine condition of electron donor: A case study using acetate as external carbon source

► Heterotrophic partial denitrification was feasible to accumulate nitrite for anammox. ► RBCOD/NO3- ratio of 2.5 realized an ideal nitrite accumulation rate (NAR) of 71.7%. ► Exogenous denitrification benefited a higher NAR under RBCOD/NO3- ratio below 3.5. ► NAR of 60% was achieved ideally under batch-flow mode by accurate indication of pH. ► Alkaline environment (pH 9.0-9.6) repressed N2O emission in acetate famine condition.