Optimisation of wastewater biological denitrification based on mathematical simulation

With increasing urbanisation and industrial activity, municipal wastewater treatment faces growing challenges, particularly in nitrogen removal. This study developed a bioelectrochemical system to enhance microbial activity and nitrogen removal pathways through electrochemical properties. A mathematical evaluation model was constructed, and experiments were conducted to analyse the effects of electrochemical characteristics, dissolved oxygen levels, and carbon/nitrogen ratios on nitrogen migration, conversion, and removal. Results showed that applying a power supply shortened the domestication time of nitrifying bacteria and improved nitrogen removal efficiency. Under high dissolved oxygen conditions (4.5–5.5 mg/l) with applied voltage, NO₃⁻-N removal reached 73.72%. At a high carbon/nitrogen ratio of 8, removal increased to 89.63%. With 0.2 V constant power, high dissolved oxygen, and a high carbon/nitrogen ratio, NO₃⁻-N levels dropped to nearly 0 mg/l, achieving a total nitrogen removal rate of ≈99%. These findings demonstrate the effectiveness of the proposed bioelectrochemical denitrification method, offering a new technological approach for municipal wastewater treatment.