Simultaneous Distribution Method of Influent Flow Rate and Volume of Step Feeding Anoxic/Oxic Biological Nitrogen Removal Process

摘要

To get the optimal influent flow rate distribution and volume distribution of step feeding anoxic/oxic (A/O) biological nitrogen removal process (SFAOBNR), a simultaneous distribution method was proposed in this study. The amount of chemical oxygen demand (COD) required for denitrifying unit mass of nitrate nitrogen (NO3--N) (alpha, mg COD/mg NO3--N) was taken as the key parameter for influent flow rate distribution and volume distribution of the anoxic and oxic units of SFAOBNR. A step feeding process with three stages of denitrification-nitrification was studied by activated sludge model No. 1 and a clarification-thickening model for sedimentation tank with GPS-X software. Meanwhile, by comparing with published data, the optimum value of a was determined. Results indicated that the optimum value of a was 4.0 mg COD/mg NO3--N according to the characteristics of influent. The method proposed in this study can distribute the influent flow rate and the volumes of the anoxic and oxic units of SFAOBNR quickly and make full use of COD in influent for denitrification which not only can improve the total nitrogen removal efficiency but also reduce the energy consumption of biological wastewater treatment plants.