Paper details

Title:

Use of Olive Mill Wastewaters and Urban Wastewater as Nutrient Medium and CO₂ Biofixation for Biomass Production of Microalgae

Author(s):

Maaitah, M., Hodaifa, G., Malvis, A., Sánchez, S.

Document(s):

Abstract:

Olive oil industry generates wastewater characterized by high organic and inorganic load, which includes sugars, phenolic compounds, polyalcohol, pectin, lipids,... This liquid effluent and urban wastewater can provide nutrients to produce an algal biomass with high added value. On the other hand, microalgae treat this wastewater by removing its nutrients. Chlorella pyrenoidosa is a green unicellular alga that can produce lipids. In this sense, a mixture of olive-mill wastewater (OMW from washing of fruits and oils) and urban wastewater (UW) as culture media was studied, using concentrations of CO2 10%, temperature 25°C, pH=8, air flow of 1 v/v/ min, and under light dark cycle (12 h lighting per day). All experiments were conducted with photobioreactors of 0.5 dm3 of useful capacity. Fundamentally, this study tries to evaluate the growth kinetics (maximum specific growth rate, µm, and volumetric biomass productivity, Pb) as well as the formation of lipids in the biomass formed. At lab level, a concentration of 50% wastewaters from washing of fruit, 30% wastewaters from washing of oils and 20% of UW with 10% of CO2 (in the gas phase of photobioreactor inlet) permits to reach the highest values of µm and Pb, 0,0353 h-1 and 4.25 10-3 g dm-3h-1, respectively. Carbon and oxygen were the most abundant elements in the biomass composition obtained using all culture media essayed. In terms of lipids content, a 46.4% (regarding to weight dry of biomass) was reached at the same culture conditions. Lipid samples obtained from C. pyrenoidosa were converted into fatty acid methyl ester (FAME) through a transesterification process. The fatty acid profiles obtained are suitable for biofuel production. It is necessary to highlight that the percentages of polyunsaturated and essential fatty acids increased when CO2 was used.

Keywords:

biofuel, lipids, olive-mill wastewater, Chlorella pyrenoidosa, CO₂ biofixation

Topic:

Sustainable Resources for Decarbonising the Economy

Subtopic:

Algae and aquatic biomass prodution systems

Event:

28th European Biomass Conference and Exhibition

Session:

1DV.1.2

Pages:

107 - 112

ISBN:

978-88-89407-20-2

Paper DOI:

10.5071/28thEUBCE2020-1DV.1.2

Price:

FREE