The chapter outlines the critical role that constructed wetlands (CWs) and bioelectrochemical systems (BESs) play in addressing the escalating global challenges of water pollution and scarcity. It delves into the fundamental principles and design considerations of CWs, explaining how these engineered ecosystems mimic natural processes to effectively treat various contaminants. Additionally, it highlights the emerging field of BESs, emphasizing the integration of biological and electrochemical processes for enhanced wastewater treatment and resource recovery. It explores the synergy between microorganisms and electrodes, demonstrating how BESs not only treat wastewater but also harness the energy and valuable by-products. The chapter also underscores the interdisciplinary nature of the subject, emphasizing the collaboration between environmental scientists, engineers, and biotechnologists in advancing these technologies. It sets the stage for the subsequent chapters by providing a roadmap for readers to navigate the complexities of CWs and BESs, fostering a deeper understanding of their potential in shaping the future of sustainable water management.