BIOGAS SLURRY AS NUTRIENT SUPPLEMENT FOR ALGAL CULTIVATION Poonam Choudhary, Sanjeev K Prajapati, Pushpendar Kumar, Pushap Chawla, Anushree Malik Applied Microbiology Lab, IIT Delhi ABSTRACT : Anaerobic digestion (AD) of biomass creates a nutrient-rich waste stream, called digestate or slurry, which can be spread as crop fertilizer but has the potential to be used as a nutrient source for micro-algal growth. Recycling the nutrients from AD and assimilating them into algal biomass can result in further feedstock for the process without incurring the monetary or environmental costs of using nitrogenous or phosphorus fertilizers while simultaneously remediating the liquid waste stream from the process. In order to test the suitability of BGS as nutrient supplement, experiments were conducted with different concentrations of slurry (10- 100% v/v) for 12 days. In the first test, best performing native algae, Chroococcus sp.1 was used and the growth potential was compared in terms of chlorophyll-a concentrations. The obtained results showed that 30% slurry concentration is the optimum concentration for the growth of algal strains. Problems associated with BGS STORAGE SPREADING FERTILIZATION TRANSPORTATION & DISCHARGE PHYSICAL TREATMENT CHEMICAL TREATMENT SEDIMENTATION CENTRIFUGATION Significantly reduced Odor Less than 1% solids BIOLOGICAL TREATMENT PRESSURIZED FILTERATION FILTERATION Growth potential of Chroococcus sp.1 in varying conc. of BGS Algae cultivation in 30% slurry 30% Slurry+70% TP : Optimum concentration for algal cultivation Conclusion: Integrating algal production with animal waste treatment could be made environmentally effective as well as economically viable in a not distant future Acknowledgement Financial support: MNRE, GoI Experimental assistance : Mr. Sabal Singh & Mr.Vinod Kumar