The long history of research into algae-based wastewater treatment, pioneered by algologists Oswald and co-workers (1953), was designed as a technology to carry out the dual role of microalgae used for wastewater treatment and protein production. It began with Golueke and Oswald (1965), who gained insight into the economic aspects of microalgae-based pond wastewater treatment technology and its poten­tial alternative sources of renovated effluent and protein production. Microalgae have been used extensively as appropriate treatment technologies in pond wastewa­ter treatment since the early 1950s (Oswald et al., 1953; Oswald and Gotaas, 1957; Fallowfield and Garrett, 1985; Lincoln and Earle, 1990; Ghosh, 1991; Oswald, 1991; Borowitzka, 1999; Oswald, 2003; Hanumantha Rao et al., 2011). Phycoremediation can provide a more sustainable long-term solution than any other type of wastewa­ter treatment in which a biological method is employed because microalgae have the greater capacity to fix CO2 by photosynthesis and efficiently remove nutrients from overloaded wastewaters at minimal cost (Hirata et al., 1996; Murakami and Ikenouchi, 1997). The most efficient nutrient removal from wastewater has been investigated using algal strains with special attributes such as extreme temperature tolerance, chemical composition of high-value by-products, heavy metal accumula­tion, and mixotrophic growth inter alia. The microalgae strain Phormidium was isolated from a polar environment below 10°C, and the capability of this strain to remove inorganic nutrients in wastewater during spring and autumn of cold climates was studied by Tang et al. (1997). Common microalgae in wastewater treatment include Chlorella, Oscillatoria, Scenedesmus, Synechocystis, Lyngbya, Gloeocapsa, Spirulina, Chroococcus, Anabaena, and others. Among these, the universally grown Chlorella species (vulgaris) has been used for wastewater treatment throughout the world. They are microalgae that can grow in nitrogen (N) and phosphorous (P) nutrient-enriched municipal wastewater and convert wastewater containing N and P into algal biomass (Green et al., 1995; Benemann and Oswald, 1996; Olguin, 2003; Orpez et al., 2009). Other efficient microalgal species used to remove N and P in var­ious industrial effluents include Botryococcus braunii, which was used for primary treated sewage waste (Sawayama et al., 1995); Scenedesmus obliquus, which was used in the treatment of urban wastewater (Martinez et al., 2000); and artificial wastewater (Gomez Villa et al., 2005). The pollutants are recovered from the system by harvesting biomass (Adey et al., 1996). Aside from microalgal biomass build­up, luxury reserved materials in the form of pigments, protein, antioxidants, amino acids, and other bioactive compounds make them ideal for stripping nutrients. High — rate wastewater treatment of hazardous or organic pollutants has been carried out by microalgae with special attributes. The most widely studied microalgal strains are Chlorella, Scenedsmus, and Ankistrodesmus species, in which various industry effluents were used, such as paper industry wastewaters, olive oil production waste­water, and mill wastewaters (Ghasemi et al., 2011; Rawat et al., 2011). Microalgal strain selection plays an important role in HRAP wastewater treatment. Microalgal collections house only a few thousand different microalgal strains that can efficiently support wastewater treatment and biomass production for value-added by-products and meet near-future demands for alternate biofuels. Therefore, we need to concen­trate on effective microalgal strains in combination with recent advances in genetic engineering and material science to fix the problem.