Innovative and cost-effective approaches to enhance nutrient removal and energy efficiency in conventional wastewater treatment plants

The 42 Evler Wastewater Treatment Plant (WWTP), originally operated as a conventional activated sludge (CAS) system, was transformed into an advanced biological system using the Modified Ludzack-Ettinger (MLE) process scheme, significantly improving nutrient removal and energy efficiency. Integrating anoxic-aerobic zones and optimizing microbial dynamics enhanced treatment performance, with total nitrogen (TN) and total phosphorus (TP) removal efficiencies increasing from 28.1 % to over 80 % and from 56.4 % to 89.6 %, respectively. These improvements were achieved alongside a 32.9 % reduction in energy consumption. Detailed microbial analyses identified key new species, such as Nitrosomonas and Thiobacillus, whose roles in nitrification and denitrification pathways were pivotal for improving treatment performance. Integrating anoxic-aerobic zones, advanced aeration systems, and optimized sludge management further contributed to the system's sustainability. Evaluating pollutant removal efficiencies before and after the upgrade, supported by statistical analyses, confirmed significant improvements in BOD₅, COD, TN, TP, and TSS removal. The microbial community was comprehensively assessed, revealing the specific roles of microorganisms in nutrient removal and process optimization. These advancements align with stringent discharge standards and global environmental goals, demonstrating how microbial insights and process innovations can modernize wastewater treatment. The upgraded system provides a scalable and efficient framework for addressing environmental and operational challenges in wastewater management.