Pilot-scale structured bed reactor with intermittent aeration: a novel strategy for simultaneous nitrogen and carbon removal from domestic sewage with industrial contribution

The treatment of domestic sewage with industrial contributions presents significant challenges due to the variability in influent characteristics and the presence of industrial pollutants. This study develops a novel and efficient pilot-scale system for simultaneous nitrification and denitrification (SND) to remove carbon and nitrogen from real domestic sewage using intermittent aeration. The structured bed reactor with intermittent aeration (SBRIA) achieved a total nitrogen removal efficiency of 54 ± 20%, with nitrification at 62 ± 20% and denitrification at 85 ± 15%. The system also demonstrated effective removal of organic matter, with a 57 ± 28% reduction in total chemical oxygen demand (CODT) and 87 ± 16% in COD after sedimentation (CODs), indicating its efficacy in organic matter degradation, although a decanting unit may be required to optimize solids separation. Additionally, the system successfully managed pH and alkalinity consumption without the addition of alkalinizing agents, maintaining mean values of 7.0 ± 0.8 for pH and 166.8 ± 79.8 mg L⁻¹ for alkalinity. The SBRIA showed resilience to toxic shocks, adapting to the high influent variability typical of wastewater with industrial contributions. Overall, the SBRIA offers a promising, cost-effective solution for wastewater treatment, demonstrating significant potential for large-scale applications in removing nitrogen and organic matter.