Assessing Actions to Enhance the Biological Treatment Process in a Liquid Waste Treatment Plant

The work discusses the challenges faced by Liquid Waste Treatment Plants (LWTPs) in meeting strict discharge limits while optimizing efficiency and minimizing environmental impact. The study focuses on a specific LWTP, addressing issues related to organic substance and nitrogen removal. Over a two-year period data was collected and analysed, The LWTP's current configuration struggled to treat the maximum authorized organic and nitrogen loads, leading to a transition from a Conventional Activated System (CAS) to an Intermittent Aeration System (IAS-CS), which also proved ineffective. To address the challenges, a new plant configuration was proposed, involving the replacement of submerged aerators with fine bubble diffusers and the implementation of intermittent aeration controlled by NOx-N concentration. Mathematical models, including Activated Sludge Model no.3 and the Takacs Model, were used to simulate the new configuration's performance. The simulation results indicated improved efficiency in treating liquid waste up to authorized maximum levels. Additionally, the proposed scenario analysis considered variations in sludge age, process temperature, and aeration control, demonstrating the potential for effective liquid waste treatment by maintaining a Sludge Retention Time (SRT) above 5 days. Overall, the research addresses the multifaceted challenges faced by LWTPs and proposes technical solutions for enhanced performance in treating organic substances and nitrogen in liquid waste.