Wastewater contains both nutrients and hazardous chemical compounds depending on its source (i.e., refinery, domestic, urban, hospital, agriculture, and industry). Algae can convert wastewater contaminants and simultaneously generate oxygen via photosynthesis into less dangerous compounds. The integration of this biotechnology will be a complementary approach to the existing wastewater treatment plant, which uses either conventional or advanced oxidation processes to treat the wastewater. This book chapter discusses the application of this aquatic organism in live-cell forms for the bioremediation of wastewater. The subtopics discussed in this book chapter are algae classification, bioremediation of wastewater using algae, bioenergy cogeneration using algal biomass, and algal practicality and limitations. The practicality and advantages of algae in terms of carbon footprint reduction, as well as their limitations, are critically explored. © 2022 Elsevier Inc. All rights reserved.