Removal of NH3-N, NO2-N and UV254 Organics by Biological Activated Carbon Fiber

A novel water treatment technique, biological activated carbon fiber (BACF), was applied to remove NH₃-N and NO₂-N from slightly polluted water. Activated carbon fiber (ACF), inoculated with microorganism, was used as packing material. Its performance was compared with that of biological activated carbon (BAC) and ACF. Much higher efficiency of NH₃-N and NO₂-N removal from slightly polluted water was achieved by BACF than BAC and ACF. The results of removal efficiency of NH₃-N, NO₂-N, UV254 organics and microorganism morphology at different period of water treatment suggested that physical adsorption of NH₃-N, NO₂-N and UV254 organics by BACF was responsible for the first five days, and the quantity microorganism formed on the activated carbon fiber was much less by scanning electron microscope (SEM), but after which NH₃-N, NO₂-N and UV254 organics were biodegraded by inoculated microorganisms. The dynamic steady state between physical adsorption and biodegradation was about one week. At this period, the appearance, quantity and species of microorganism formed on the activated carbon fiber were also much more. After the system achieved equilibrium, the BACF column exhibited high adaptation to shock loading, elevated temperature, and flow rate. 90.6%, 96.2% and 90.8% removal efficiencies for NH₃-N, NO₂-N and UV₂₅₄ organics were respectively achieved during the 45-day operating period. Even on the 45-day operation, the removal efficiency for the three kinds of pollutants was achieved above 72.0%, 60.0% and 55.0%, respectively. The results also demonstrated that NO₂-N removal was not affected by NH₃-N, which was concluded that the denitrification was occurred in BACF column. A simple periodic backwash system was used to regenerate the used BACF and BAC.