CULTURE OF MICROALGAE IN MIXED WASTEWATER STREAMS

MOHEIMANI, N.; CUELLO, M. C.; CHAMORRO, E.

Nantes

Congreso; 6th Congress of International Society for Applied Phycology; 2017

Universidad de Nantes

Microalgae cultivation in waste effluents can be feasible for efficient removal of nutrients. Additionally, there is potentiallyno?sludge? generation and produced biomass can generate revenue. Nevertheless, to achieve optimal algal growth, in most cases these effluents must be diluted (using freshwater). Freshwater is a finite resource and its use should be avoided.In here, we studied the effect of culturing microalgae in mix of dairy farm effluent with 13mg.L-1 P-Phosphates, 70 mg.L-1 N-Nitrates and 120mg.L-1 N-Ammonia concentrations and cheese whey effluent with 154mg.L-1 P-Phosphates, 0.80 mg.L-1 N-Nitrates and 48.5mg.L-1 N-Ammoniaconcentrations.For bioprospecting purpose, Scenedesmusdimorphus and Chlorella pyrenoidosa were cultured at laboratory scale as a) mono-species and b) Five mixed compositions of dairy farm and cheese whey effluents (Mix1: 0% Stream 1 - 100% Stream 2; Mix2: 25% Stream 1 - 75% Stream 2; Mix3: 50% Stream 1 - 50% Stream 2; Mix4: 75% Stream 1 - 25% Stream 2; Mix5: 100% Stream 1 - 0% Stream 2).Three out of the fifteen experiments showed highest algal productivity and therefore selected for outdoor cultivation. These were: Scenedesmusdimorphus in two mixes: a- 50/50 andb- 25/75dairy farm/cheese whey wastewaters ratios and c- Chlorella pyrenoidosa cultured in 25/75 mixture of same wastewaters. These culture conditions were further cultured in batch mode under outdoor conditionsin 5L airlift driven mesocosoms. Growth (μ, yield, productivity and biochemical composition) as well as nutrient removal rates were measured using internal standard methods.Scenedesmusdimorphus in the 50/50 blending under outdoor conditions showed the highest growth rate (0.38), biomass yield (2.07g.L-1) and nutrient removal rates (99% P-Phosphates, 96% N-Nitrates and 70% N-Ammonia reduction). However, the other two conditions resulted in higher lipid content (b- 22.6% and c- 21.5% respectively).Our results clearly indicated that mixing these waste effluents with different nutrient composition and color can enhance both nutrient ratio and light availability (foremost in dark wastewaters) for microalgae cultivation. Other parameters, such as pH, could be also corrected by mixing wastewaters.[1] Fenton, O. and D. Ó hUallacháin (2012). "Agricultural nutrient surpluses as potential input sources to grow third generation biomass (microalgae): A review." Algal Research 1(1): 49-56.[2] Hena, S., S. Fatimah and S. Tabassum (2015). "Cultivation of algae consortium in a dairy farm wastewater for biodiesel production." Water Resources and Industry 10(0): 1-14.[3] Riaño, B., S. Blanco, E. Becares and M. C. García-González (2016). "Bioremediation and biomass harvesting of anaerobic digested cheese whey in microalgal-based systems for lipid production." Ecological Engineering 97: 40-45.