Phycoremediation by High-Rate Algal Ponds (HRAPs) - Biotechnological Applications of Microalgae - page 186

The application and advantages of phycoremediation include (Olguin, 2003)
1. Nutrient removal from both municipal and industrial wastewater or effluent
enriched with high organic matter
2. Nutrient and xenobiotic compound removal with the aid of algae-based
biosorbents
3. Efficient treatment of acidic and heavy-metal wastewater
4. Increasing oxygenation of the atmosphere
5. CO 2 sequestration
6. Improving effluent quality
7. Transformation and degradation of xenobiotics
8. Biosensing of toxic compounds by algae
12.4 ALGAE SPECIES USED FOR PHYCOREMEDIATION
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 poten-
tial alternative sources of renovated effluent and protein production. Microalgae
have been used extensively as appropriate treatment technologies in pond wastewa-
ter 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 wastewa-
ter treatment in which a biological method is employed because microalgae have
the greater capacity to fix CO 2 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 accumula-
tion, 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 var-
ious 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