Experimental and optimization studies on phycoremediation of dairy wastewater and biomass production efficiency of Chlorella vulgaris isolated from Ganga River, Haridwar, India.

Abstract

Dairy wastewaters (DWW) are rich in several pollutants, including high biochemical oxygen demand (BOD) and chemical oxygen demand (COD), and their unsafe disposal may cause damage to the environment. In this study, Chlorella vulgaris (identified as NIES:227 strain based on 28s rRNA sequencing) was isolated from the freshwater habitat of the Ganga River at Haridwar, India, and further tested for its efficacy in treating DWW. The phycoremediation experiments were conducted using three different DWW concentrations (0, 50, and 100%), operating temperatures (20, 25, and 30°C), and light intensities (2000, 3000, and 4000lx) using response surface methodology. Results showed that after 16days of experiments, a significant (P < 0.05) reduction in BOD (96.65%) and COD (87.50%) along with a maximum biomass production of 1.757g/L was achieved using 57.72% of dairy industry wastewater, 24.16°C of reactor temperature, and 3874.51lx of light intensity. The RSM models had coefficient of determination (R2) values above 0.9459 with a minimum difference between measured and predicted responses. Therefore, the findings of this study suggest that the isolated C. vulgaris can be effectively used to treat dairy wastewater along with significant production of algal biomass which can be further used for the generation of low-cost biofuel and other materials.