Wastewater with chemicals and excessive nutrients is degrading the ecosystems on which we depend. It is a growing threat to health and the environment, especially due to increasing urbanization, industrialization, and population growth. Globally, waste resources, such as wastewater have great potential, and it is only timely to treat them as an opportunity for the circular bioeconomy. Wastewater bioremediation using microalgae is a strategy that simultaneously mitigates and transforms waste resources into a portfolio of marketable products. This is a promising solution for the climate and nature. In this bias, by integrating science and nature, the book highlights the strategic role of microalgae in managing wastewater, capturing resources that can be reused and transformed into a spectrum of useful products. This book combines theoretical foundations, case studies of experiments, practical applications, challenges, and perspectives on the future of microalgae-based wastewater remediation.