Rapid start-up strategy of partial denitrification and microbially driven mechanism of nitrite accumulation mediated by dissolved organic matter

[Display omitted] •A strategy was proposed for the rapid start-up of partial denitrification.•Thauera and OLB13 played key roles in nitrite accumulation.•Disparity between narH, ncd2 and nirK, nirS contributed to nitrite accumulation.•DLD was mainly responsible for the dissolved organic matter transformation. The rapid start-up of Partial denitrification (PD; nitrate to nitrite) was investigated based on the analysis of microbially driven mechanism of nitrite accumulation mediated by Dissolved organic matter (DOM) in this study. The nitrate to Nitrite transformation ratio (NTR) > 90% and effluent nitrate