In addition to producing bioenergy and molecules with high added value, microalgae have been recognized as an efficient microorganism for wastewater treatment. However, a major obstacle preventing its widespread use is the high energy cost of pretreatment, cultivation and downstream processes. Different types of wastewaters have been tested as culture mediums for microalgal biorefinery system. This review gives a summary of the most used microalgae strains for wastewater treatment, as well as information on the physical and chemical characteristics of domestic, agricultural, and industrial wastewaters. It also discusses wastewater pretreatment techniques, nutrient uptake and removal, biomass production and biomolecules productivities. There is also discussion on how microalgae remove contaminants from wastewater. Additionally, the problems and restrictions of microalgae-based wastewater treatment are explored, and recommendations are made for additional study and advancement. This literature review demonstrates that microalgae monoculture systems have proven to be beneficial as an innovative wastewater treatment technology, due to its high efficiencies in pollutant removals and biomolecule production; however, the upstream and downstream treatment pose a limit to industrialize the process. Until now, there has been no conventional design of the wastewater treatment process using microalgae in the biorefinery system, which constitutes a huge gap to assess a real life cycle assessment (LCA) and techno economic analysis (TEA).