Amruta Padgaonkar

Microorganism-based bioremediation is a well-sought after method for industrial wastewater treatment and forms the primary stage. The current research suggests using Spirulina platensis as an organism of choice for bioremediation. This study provides an insight into the potential use of primary-treated wastewater as the growth media for Spirulina platensis. The tolerance of S. platensis was confirmed for metals such as mercury (Hg), cadmium (Cd), manganese (Mn), zinc (Zn), and copper (Cu) by using media enriched with these metals. S. platensis was most tolerant to Hg followed by Cd and Cu. Further, it is suggested that the biomass and bioactive compounds extracted from S. platensis be tested for their application in animal and aquaculture feed, supplements, and pharmaceuticals.

Excessive generation of wastewater is one of the major reasons for pollution in natural reservoirs. Given the normal circumstances, natural water bodies revive and rejuvenate themselves; but upon increased waste load, the self-revival system of the ecosystem slows down, causing water pollution. Hazardous waste, especially heavy metals and organic pollutants, have affected the ecology to the detriment of humans. Thus, the need arises for wastewater treatment, before its discharge. Current methods undertaken include the use of physical settling of solid waste, filtration, aerobic and anaerobic microbes, and chemical treatments. Low removal of pathogens, dependence on the uninterrupted power supply, high maintenance cost, generation of explosive biogas and bioaccumulation of chemicals are some disadvantages of activated sludge technology, one of the modern technologies used. Hence, the focus has been shifted on organisms capable of metabolizing, immobilizing or absorbing toxic compounds from their environment, making it both environment-friendly and cost-effective. This review provides perspicacity about the generation of sewage and the various methods available for its treatment. Emphasis is made on bioremediation using Spirulina platensis. Since the organism assimilates the bioavailable contaminants of sewage water photosynthetically; it can overcome the demerits of conventional methods. It also discusses possibilities of using Spirulina grown on the sewage as a food supplement, animal fodder or source of bioactive compounds.