Olive mill wastewater treatment using coagulation/flocculation and filtration processes

Olive mill wastewater (OMWW), a pollutant resulting from the olive oil industry, poses a serious ecological challenge due to its high pollution load. This effluent is highly concentrated in chemical oxygen demand (COD), which is 200 times higher than that of sewage wastewater. Moreover, OMWW is char...

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Main Authors: Layla Moustafa Fleyfel, Joseph Matta, Nicole Fakhoury Sayegh, Nasma Hamdi El Najjar
Format: Article
Language:English
Published: Elsevier 2024-11-01
Series:Heliyon
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Online Access:http://www.sciencedirect.com/science/article/pii/S2405844024163797
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author Layla Moustafa Fleyfel
Joseph Matta
Nicole Fakhoury Sayegh
Nasma Hamdi El Najjar
author_facet Layla Moustafa Fleyfel
Joseph Matta
Nicole Fakhoury Sayegh
Nasma Hamdi El Najjar
author_sort Layla Moustafa Fleyfel
collection DOAJ
description Olive mill wastewater (OMWW), a pollutant resulting from the olive oil industry, poses a serious ecological challenge due to its high pollution load. This effluent is highly concentrated in chemical oxygen demand (COD), which is 200 times higher than that of sewage wastewater. Moreover, OMWW is characterized by a strong acidity, high content of fatty matter, and high concentration of phenolic compounds.In this study, coagulation/flocculation and filtration processes were investigated in order to decrease the pollution load of OMWW for potential reuse in olive orchard irrigation. First, two successive coagulation/flocculation steps were applied to a centrifuged OMWW. Lime and aluminum sulfate (alum) were used as coagulants by testing different concentrations in order to select optimal conditions. Then, the efficiency of various filtration systems using activated carbon and/or natural materials (olive stones, olive leaves, sand, Celite, and gravel) was tested. pH, electrical conductivity (EC), total solid (TS), and COD were measured before and after each treatment step (coagulation or filtration). Five phenolic compounds were monitored before and after applying the selected treatment steps under optimal conditions. The quantification and valorization of the sludge derived from coagulation/flocculation were also performed.During the first coagulation/flocculation step, the results showed that the application of 8 g/L of lime combined with 7 g/L of alum allows the removal rates for EC, TS, and COD of approximately 10 %, 41 %, and 48 %, respectively. While the application of 5 g/L of lime and 4 g/L of alum during the second coagulation/flocculation step allows for lower reductions rates for TS (37 %) and higher reduction rates for COD (67 %). In addition, the resulting sludge showed its potential usage as a solid alternative fuel with a calorific value of 3295.79 cal/g. Moreover, filtration using activated carbon and gravel was found to be the optimum filtration system. The reduction rates were 51 %, 37 %, and 26 % for EC, TS, and COD, respectively.Finally, the combination of coagulation/flocculation and filtration allows the substantial elimination of the studied phenolic compounds with global reduction yields of 97 % for vanillyl alcohol, 92 % for tyrosol, and 91 % for vanillic acid and p-coumaric acid.Besides, Mediterranean countries are suffering from water shortages and the majority of olive mill trituration units are known for their artisanal types thus facing economic challenges. This research suggests a practical treatment process and the final effluent can be used to irrigate olive orchards at a rate of 170 m3 per hectare.
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spelling doaj-art-7639d3161f724facb515dc45eb4f843d2025-08-20T02:49:02ZengElsevierHeliyon2405-84402024-11-011022e4034810.1016/j.heliyon.2024.e40348Olive mill wastewater treatment using coagulation/flocculation and filtration processesLayla Moustafa Fleyfel0Joseph Matta1Nicole Fakhoury Sayegh2Nasma Hamdi El Najjar3Saint Joseph University of Beirut, Faculty of Pharmacy, Department of Nutrition, Medical Sciences Campus, Damascus Road, P.O.B. 11-5076, Riad Solh Beirut, 1107 2180, Lebanon; Corresponding author. Saint Joseph University of Beirut, Beirut, Lebanon.Saint Joseph University of Beirut, Faculty of Pharmacy, Department of Nutrition, Medical Sciences Campus, Damascus Road, P.O.B. 11-5076, Riad Solh Beirut, 1107 2180, Lebanon; Industrial Research Institute (IRI), Lebanese University Campus, Hadeth Baadba, LebanonSaint Joseph University of Beirut, Faculty of Pharmacy, Department of Nutrition, Medical Sciences Campus, Damascus Road, P.O.B. 11-5076, Riad Solh Beirut, 1107 2180, LebanonSaint Joseph University of Beirut, Faculty of Pharmacy, Department of Nutrition, Medical Sciences Campus, Damascus Road, P.O.B. 11-5076, Riad Solh Beirut, 1107 2180, LebanonOlive mill wastewater (OMWW), a pollutant resulting from the olive oil industry, poses a serious ecological challenge due to its high pollution load. This effluent is highly concentrated in chemical oxygen demand (COD), which is 200 times higher than that of sewage wastewater. Moreover, OMWW is characterized by a strong acidity, high content of fatty matter, and high concentration of phenolic compounds.In this study, coagulation/flocculation and filtration processes were investigated in order to decrease the pollution load of OMWW for potential reuse in olive orchard irrigation. First, two successive coagulation/flocculation steps were applied to a centrifuged OMWW. Lime and aluminum sulfate (alum) were used as coagulants by testing different concentrations in order to select optimal conditions. Then, the efficiency of various filtration systems using activated carbon and/or natural materials (olive stones, olive leaves, sand, Celite, and gravel) was tested. pH, electrical conductivity (EC), total solid (TS), and COD were measured before and after each treatment step (coagulation or filtration). Five phenolic compounds were monitored before and after applying the selected treatment steps under optimal conditions. The quantification and valorization of the sludge derived from coagulation/flocculation were also performed.During the first coagulation/flocculation step, the results showed that the application of 8 g/L of lime combined with 7 g/L of alum allows the removal rates for EC, TS, and COD of approximately 10 %, 41 %, and 48 %, respectively. While the application of 5 g/L of lime and 4 g/L of alum during the second coagulation/flocculation step allows for lower reductions rates for TS (37 %) and higher reduction rates for COD (67 %). In addition, the resulting sludge showed its potential usage as a solid alternative fuel with a calorific value of 3295.79 cal/g. Moreover, filtration using activated carbon and gravel was found to be the optimum filtration system. The reduction rates were 51 %, 37 %, and 26 % for EC, TS, and COD, respectively.Finally, the combination of coagulation/flocculation and filtration allows the substantial elimination of the studied phenolic compounds with global reduction yields of 97 % for vanillyl alcohol, 92 % for tyrosol, and 91 % for vanillic acid and p-coumaric acid.Besides, Mediterranean countries are suffering from water shortages and the majority of olive mill trituration units are known for their artisanal types thus facing economic challenges. This research suggests a practical treatment process and the final effluent can be used to irrigate olive orchards at a rate of 170 m3 per hectare.http://www.sciencedirect.com/science/article/pii/S2405844024163797Olive mill wastewaterCoagulation/flocculationFiltrationPhenolic compounds
spellingShingle Layla Moustafa Fleyfel
Joseph Matta
Nicole Fakhoury Sayegh
Nasma Hamdi El Najjar
Olive mill wastewater treatment using coagulation/flocculation and filtration processes
Heliyon
Olive mill wastewater
Coagulation/flocculation
Filtration
Phenolic compounds
title Olive mill wastewater treatment using coagulation/flocculation and filtration processes
title_full Olive mill wastewater treatment using coagulation/flocculation and filtration processes
title_fullStr Olive mill wastewater treatment using coagulation/flocculation and filtration processes
title_full_unstemmed Olive mill wastewater treatment using coagulation/flocculation and filtration processes
title_short Olive mill wastewater treatment using coagulation/flocculation and filtration processes
title_sort olive mill wastewater treatment using coagulation flocculation and filtration processes
topic Olive mill wastewater
Coagulation/flocculation
Filtration
Phenolic compounds
url http://www.sciencedirect.com/science/article/pii/S2405844024163797
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AT nasmahamdielnajjar olivemillwastewatertreatmentusingcoagulationflocculationandfiltrationprocesses