Using passive atmospheric oxygenation to increase nitrification potential in a non-planted vertical flow constructed bed system

Nitrification potentials in micro-environment were examined in a non-planted vertical flow constructed bed system with an air pipe. The results showed that nitrification potential was significantly correlated with the dissolved oxygen inside the system. Enhanced nitrification of 10.15 g/m²·d was achieved, twice as much as the 4.71 g/m²·d obtained in the traditional one. Atmospheric oxygenation by the air pipe was a remarkable 23.7 g/m²·d, which improved the aerobic micro-environment for extra nitrification. Passive atmospheric oxygenation, which was increased by the air pipe without energy consumption, stimulated the growth of nitrifying bacteria and provided favorable habitats of bacterial richness. This results in high nitrification potential in the constructed bed, which is good for high-concentration rural wastewater treatment.