The concentrations of different inorganic nitrogen compounds
in the integrated system were shown in Fig. 5. Since the dominant
inorganic nitrogen compound in coking wastewater was ammonia,
TIN was defined as the sum of NH3-N, NO2
−-N and NO3
−-N
herein. As it could be found from Fig. 5(a), the removal of NH3-N
occurred in Reactor A, O1 and O2 and the concentration of NH3-N
was almost the same between Reactor O2 and ZVI