<p>The increasing demand for sustainable wastewater treatment solutions has highlighted the importance of algal technologies in managing domestic, industrial, and aquaculture wastewater. Algae-based treatment systems offer a promising approach due to their ability to efficiently remove nutrients and pollutants while generating valuable biomass. This review explores the significance of algal technologies in wastewater treatment, focusing on the removal rates and benefits of algae in purifying various types of wastewaters, including domestic sewage, industrial wastewater, and aquaculture wastewater. Additionally, it summarizes the application and research progress of algal-bacterial symbiotic systems, algal-bacterial granular sludge systems, and the co-cultivation of various algae species. Recent developments, including the integration of machine learning to optimize treatment processes and innovative bioreactor designs to enhance algal performance, are also discussed. Furthermore, the review addresses pilot-scale applications and sustainability assessments, providing insights into the current challenges and prospects within the algae-based industry, which has recently shown significant promise.</p>