Simulation and Analysis of the Capacity of A2/O Wastewater Treatment Plant Based on ASM2D Model

Abstract

Based on ASM2D model, an improved A2/Ourban wastewater treatment plant (WWTP) was simulated to study the standard-reaching states of effluent COD, TN and NH4 +-N given a certain volume of influent water but different distribution ratios. The results show that when the total volume of influent water is 50~100 thousand tons per day (t/d), both COD and NH4 +-N can meet Class 1A of GB18918-2002. When the total volume of influent water is within the design value of the WWTP, the Class 1B standard-reaching rate of TN can reach above 90%. The more uniform and disperse the influent’s distribution, the higher the standard-reaching rate of TN and the better the COD, TN and NH4 +-N will be. After analyzing the standard-reaching rates, the study finds that under the precondition that the standard-reaching rate of Class 1A is above 90%, the maximum operating capacity of the WWTP with three A2/Oprocesses, each of which designed 50,000 t/d, is 100,000 t/d.