Phycoremediation of sewage wastewater and industrial flue gases for biomass generation from microalgae

Abstract

Phycoremediation or microalgae cultivation using sewage with industrial flue gases is a promising concept for integrated nutrient removal and sequestration respectively with subsequent biomass generation in order to control environmental pollution. In the present study sewage wastewater (SWW) and industrial flue gas was supplied in batch and continuous mode for cultivation of microalgae Chlorella vulgaris. Chlorella vulgaris was very effective in reduction of chemical concentrations (COD, NO3¯, SO4¯, and PO4¯) in SWW along with flue gas (CO2, NOx and SOx). COD removal was achieved up to 78% in batch mode and 42% in continuous mode. The other nutrients from the sewage wastewater were removed up to 75% whereas, with continuous mode 55%. Concerning the flue gas treatment studies, Chlorella vulgaris removed CO2 up to 64% in batch mode and when grown in continuous mode it was up to 72%. The SOx and NOx concentrations were reduced up to 62% and 63% respectively in batch mode and the removal efficiencies of the same were 59% and 55% in continuous mode. Both batch and continuous mode showed the maximum biomass productivity in hetero and mixotrophic cultivations. While average biomass productivity in mixotrophic continuous mode was higher as 1.0 g/L. Fourier infrared spectroscopy examination of algal biomass revealed the presence of –OH, –COOH, NH2, and = O organic compound groups. It was concluded from the results that C. vulgaris was very effective in the treatment of SWW and industrial flue gas on the other hand the biomass obtained is a sustainable green energy source. Keywords: Phycoremediation, Sewage wastewater (SWW), Flue gas, Microalgae, Fourier transform infrared spectroscopy, Chlorella vulgaris