Succession of Microbial Community Structure and Co-occurrence Network Dynamics during the Transition from Anaerobic Sludge to Aerobic Cultivation

The transition between anaerobic and aerobic conditions represents a fundamental ecological process occurring ubiquitously in both natural ecosystems and engineered wastewater treatment systems. The aerobic adaptation process triggers substantial restructuring of microbial community composition in response to environmental gradients, driving functional specialization across diverse microbial taxa. This study employed systematic sampling across critical transition phases: initial anaerobic sludge (D0), early aerobic adaptation (D1, D3, D5), and stabilized aerobic operation (D15, D30), with COD and nitrogen removal efficiencies monitored as key performance metrics throughout the aerobic transition process.