Problems of environmental pollution global warming and high energy consumption have, in recent years, brought waste treatment technologies to the fore. As the scientific world turns to sustainable, environment friendly and ecologically sound energy sources, microalgae-based technologies have become one of the most intensely studied subjects in academia. This book delves deeper into the emergence of microalgae as the green alternative that could lead the world towards adopting a circular economy and zero-discharge approach. With insights from professors and industry experts in the field, this book provides new perspectives on the day-to-day environmental applications of microalgal technologies in waste treatment and management as well as recycling. It also explores the environmental impact of traditional waste treatment and recovery technologies and highlights how algae-based technologies can serve as an eco-friendly alternative in microplastic removal and biofuel production. This book equips readers with the essential knowledge on algae-based phycoremediation technologies, with special emphasis on their use in conventional treatment facilities to remove harmful contaminants and stabilize pH for effective bacterial treatment. This is a valuable resource for environmentalists, scientists, and technologists around the world. It will also be of interest to academics and students within the disciplines of Phycology, Water Systems Engineering, Environmental Science and Remediation, and Sustainable Development.