Enhanced nitrogen removal from reject water of municipal wastewater treatment plants using a novel excess activated sludge (eas) based nitrification and denitrification process

Yongzhe Yang, Xiaoxia Yang, Wei Li, Xinchao Guo

School of Environmental and Municipal Engineering, Xi an University of Architecture and Technology Xi an 710055, P.R. China

Abstract


In this study, a novel excess activated sludge (EAS) based nitrification and denitrification process was developed using EAS to provide nitrifiers and denitrifers for nitrogen removal from the reject water of a municipal wastewater treatment plant (MWWTP). This can achieve a significant reduction in the nitrogen (N) loading in wastewater treatment plants. The results show that the ammoniacal-nitrogen (NH4+-N) and total nitrogen (TN) removal efficiencies were in the range from 74.7% to 93.1% and 77.4% to 87.9%, respectively. The TN removal efficiency was significantly improved when the step-feed strategy was employed. Therefore, from the technical perspective, the EAS based reject water treatment process can potentially be an alternative pathway for N removal from the reject water. However, for its full-scale application, integrated cost-effective analysis of process capabilities and/or its potential effects on dewaterability of EAS should be considered.

Keywords


denitrification; excess activated sludge; nitrification; reject water treatment

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