Soutenance de thèse : Caroline MIYAZAKI

Optimization of hybrid aerated vertical/horizontal flow treatment wetland

Doctorante : Caroline MIYAZAKI

Laboratoire INSA : INRAE

École doctorale : ED206 Chimie de Lyon (Chimie, Procédés, Environnement)
 

The combination of stricter local regulations and the need for higher capacity plants has prompted companies in the wetland treatment sector to prioritize research and development initiatives aimed at enhancing total nitrogen (TN) removal and minimizing system footprints. In response to these challenges, it was created the Rhizosph'air system to be resilient, compact, and robust, with a capacity to serve communities of 2,000 to 10,000 PE. This thesis contributes to the optimization of total nitrogen (TN) removal while addressing operational challenges related to environmental protection and wastewater reuse. Chapter 2 provides an overview of key topics related to the Rhizosph'air system, including nature-based solutions (NbS) and aerated treatment wetlands (TW). It identifies key research areas for improvement, including oxygen transfer and nitrogen dynamics, to enhance TN removal. Chapter 3 is dedicated to the analysis of the impact of aeration strategies on system hydrodynamics. To this purpose, tracer tests have been employed to assess both internal and outlet responses. Hydraulic parameters and modeling provided valuable insights into the system's behavior. Chapter 4 examines a range of experimental conditions, demonstrating that inflow-based aeration strategies promote equilibrium between aerobic and anoxic environments, thereby optimizing TN removal. Furthermore, the strategy suggests using the primary filter for generating nitrates during aeration and allowing denitrifying bacteria to consume them during non-aeration periods and batch-hour. The utilization of organic carbon from raw wastewater is also a key aspect of this strategy. Finally, Chapter 5 examines the proposed aeration strategy, its limitations, and the resilience of the hybrid system. It also assesses the applicability of the N-k-C* model and investigates the potential for real-time aeration control using online sensors, including bending points and model predictions. This research advances the understanding of aeration processes and TN removal, offering innovative strategies for improving wetland treatment performance in small communities