Paper details

Title:

Olive Mill Wastewater Treatment by Microalgae and Energy Compounds Production

Author(s):

Maaitah, M., Hodaifa, G., Sánchez, S.

Document(s):

Abstract:

Pollution, acute shortages of fresh water, energy and climatic changes represent a major problem for the world. Wastewater from olive oil mills (OMW) is a source of pollution without definitive solution so far. The huge quantities of OMW generate many environmental problems as it is characterized by a high organic and inorganic load, including protein, sugars, phenolic compounds, polyalcohol’s, pectin’s, lipids and mineral salts. These different nutrients allow the transformation of OMW from a waste to a substrate (by-product) for the growth of microalgae. In fact, the growth of microalgae in OMW not only treats the wastewater but also removes carbon dioxide and produce biomass with high added value. Microalgae have extensive industrial and economic potential, and can constitute a source of third generation biofuels, principally biodiesel, produced by the transesterification of algal-derived lipids. The growth response of the microalga Chlorella pyrenoidosa was studied under different concentrations of olive-mill wastewater (OMWW) as culture media formed by dilution of the OMWW (in concentrations of 5% to 100% v/v), temperature was 25°C, pH 8, air flow was provided from 1 v/v/min, under light dark cycle (12 h lighting per day). All experiments were performed batch photobioreactors, stirred tank type, of 500 cm3 of useful capacity. This study showed the evaluation of 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 % (v/v) of olive mill-wastewater permits to reach the highest values of µm and Pb, 0.034 h-1 and 3.1 10-3 g dm-3h-1, respectively. The percentage of total lipids was 47.10%. In relation to the biochemical composition, the higher values of concentrations in total chlorophyll (1.13 10-2 g dm-3), carotenoids (2.15 10-3 g dm-3) and protein (3.59 10-1 g dm-3) were obtained in cultures that use 90 % (v/v) OMMW. Oil samples collected from C. pyrenoidosa were converted into fatty acid methyl ester (FAME) through acid based transesterification. The fatty acid profiles of showed its suitability for biofuel production. It is necessary to highlight that the percentages of polyunsaturated and essential fatty acids are increased with the percentage of OMWW.

Keywords:

biofuel, microalgae, olive mill wastewater, CO₂ biofixation, nutrients removal

Topic:

Sustainable Resources for Decarbonising the Economy

Subtopic:

Algae and aquatic biomass production systems

Event:

32nd European Biomass Conference and Exhibition

Session:

1BV.3.25

Pages:

82 - 86

ISBN:

978-88-89407-24-0

Paper DOI:

10.5071/32ndEUBCE2024-1BV.3.25

Price:

FREE