A Comprehensive Literature Review on Constructed Wetlands: Design, Function, and Modeling Approaches

This article presents a comprehensive review of constructed wetlands (CWs), examining their design principles, operational functions, and modeling approaches within the context of wastewater treatment. Originating from the natural wetland systems utilized by ancient civilizations, CWs have evolved as effective, sustainable, and cost-efficient solutions for treating diverse wastewater types. The review methodology involved a thorough literature analysis using databases such as ScienceDirect, SpringerLink, and Scopus, with Mendeley Desktop© software employed for systematic archiving and organization of relevant studies. The overview section details the classification of CWs into surface and subsurface flow types, emphasizing their design considerations, including hydraulic load, pollutant removal mechanisms, and the role of vegetation. Advances in CWs modeling are discussed, highlighting the shift from simplistic empirical models to more complex mechanistic and AI-driven approaches that better capture the intricacies of CWs processes. Despite significant progress, challenges remain, particularly in integrating holistic models and addressing data limitations. The review concludes that ongoing innovation and interdisciplinary research are essential for optimizing CW performance and enhancing their role in sustainable water management. This synthesis of current knowledge aims to inform future research directions and improve the practical application of CWs in various environmental and operational contexts.