Effective partial denitrification of biological effluent of landfill leachate for Anammox process: Start-up, influencing factors and stable operation

Partial denitrification combined with Anammox is a promising approach for simultaneous removal of ammonium and nitrate from wastewaters. In this study, the start-up, influencing factors and stable operation of partial denitrification for treating biological effluent from landfill leachate were investigated. High nitrate loads (3.85 kg Nm(-3) d(-1)) and short hydraulic retention time (0.66 h) were obtained in the partial denitrification process, yielding a suitable ratio of NO2--N/NH4+-N in the effluent for downstream Anammox process. The study also revealed the importance of carbon sources, COD/NO3--N ratio and salinity in the partial denitrification. Acetate-type carbon source, COD/NO3--N ratio of about 3.0 and salinity lower than 1% favored high-efficient partial denitrification. The endogenous carbon sources from high-rate partial denitrification sludge contributed to low COD consumption in the process. During the partial denitrification, the dominant genus of Thauera was enriched, and shifted to Pseudomonas with the increase of organic removal rates. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the start-up, influencing factors, and stable operation of partial denitrification for treating biological effluent from landfill leachate. The research found a suitable ratio of nitrate/ammonium for downstream Anammox process, and highlighted the importance of carbon sources, COD/NO3--N ratio, and salinity in partial denitrification.