No abstract

In the modified Ludzack–Ettinger process, high‐energy input is required in a nitrification tank. To address this issue, a new biological nitrification–denitrification system was constructed with a trickling filter for nitrification. The effects of recirculation rate of nitrified liquor and temperature through the treatment of municipal wastewater were evaluated. The highest DN removal efficiency was observed at 6.5 h of hydraulic retention in the denitrification tank and 350% of recirculation rate of nitrified liquid against the influent flow rate. The DN removal efficiencies did not reach theoretical values for all conditions tested because the COD/N ratios in the influent often decreased to less than 5 g‐COD/g‐N and temperatures dropped to less than 15°C in winter. The former inhibited the denitrification process and the latter significantly decreased the bioactivity of nitrifying bacteria. As such, this system is suitable in tropical and subtropical areas with annual minimum temperatures of over 15°C.

No abstract

No abstract

No abstract