Algal Consortiums: A Novel and Integrated Approach for Wastewater Treatment

Urbanization, industrialization and other human-related activities discharge various inorganic and organic toxic compounds into the environment. Many physical, chemical and biological methods have been practiced, to treat contaminated wastewater: among these, the biological method of wastewater treatment by utilizing algae has been reviewed widely. However, the removal efficacy of algae monoculture is low, as compared to the algae consortium systems. The presence of microorganisms such as fungi or bacteria in wastewater can establish various relationships, such as mutualism or symbiosis with algae, which help in the removal of various organic and inorganic compounds from wastewater, thus acting as a wastewater treatment system. Heterotrophic microorganisms can segregate natural organic matter, which is released by algae in the form of dissolved organic carbon, and releases carbon dioxide, which is utilized by algae for photosynthesis. In accordance with existing studies, microalgal consortiums with bacteria or fungi occurring naturally or crafted artificially can be utilized for wastewater treatment; therefore, the present review provides an outline of the symbiotic relationships between algae and other microorganisms, and their applications in wastewater treatment. Various mechanisms—such as mutualism, commensalism and parasitism—for the removal of different pollutants from wastewater by consortium systems have been elucidated in this review; moreover, this review addresses the challenges that are restricting large-scale implementation of these consortiums, thus demanding more research to enable enhanced commercialization.