Low-carbon nitrogen removal from power plants circulating cooling water and municipal wastewater by partial denitrification-anammox

Abstract

As a reclaimed water reuse strategy, using treated municipal wastewater as power plants circulating cooling water (PPCCW) generates nitrate-rich wastewater due to evaporation requiring retreatment. An innovative low-carbon nitrogen removal process, partial denitrification-anammox (PD-A), was used in this study. The PPCCW and municipal wastewater pre-treated with 10 mg/L Fe3+ were simultaneously subjected to the PD-A process. The results showed that the total nitrogen of effluent less than 10 mg/L, and a removal efficiency of 79.67 ± 3.48% was attained. Unclassified_f_Brocadiaceae was the dominant anammox genus, with an increasing percentage (from 0.42 to 1.27%), laterally indicating the reactor stability. Furthermore, the hydrolytic acidifying bacteria SBR1031 and Bacillus increased substantially after feeding with actual wastewater, and the removal efficiencies of organic material and nitrogen increased, indicating that hydrolytic acidifying bacteria have a synergistic effect with PD-A bacteria. Finally, a novel wastewater treatment process that fully recovers carbon, phosphorus, and water was proposed.