Sorbents Coupled to Solar Light TiO2-Based Photocatalysts for Olive Mill Wastewater Treatment

The aim of this work was to couple physical-chemical approaches with photocatalysis to reduce by a simple, inexpensive way the organic load of olive mill wastewater (OMW), mandatorily prior to the final discharge. Before irradiation, different sorbents were tested to remove part of the organic fraction, monitored by measuring chemical oxygen demand (COD) and polyphenols (PP). Different low-cost, safe materials were tested, that is, Y zeolite (ZY), montmorillonite, and sepiolite. Considerable decrease of organic load was obtained, with the highest abatement (40%) provided by ZY (10 g L−1in 1 : 10 OMW). Use of the three sorbents, in particular ZY, was convenient compared to commercial activated carbons. UV light photocatalytic tests, performed using P25 TiO2on ZY-treated OMW, yielded quantitative remediation (ca. 90%). Also solar light provided significative results, PP being lowered by 74% and COD by 56%. Sol-gel anatase TiO2and N-doped anatase TiO2were also tested, obtaining good results, around-80% PP and-40% COD. Finally, an integrated approach was experimented by ZY-supported anatase TiO2(TiO2@ZY). Thisphotoreactive sorbentallowedone-pottreatment of OMW significative abatements of PP (-77%) and COD (-39%) with only 1 g L−1material, under solar light.

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Candida tropicalis as a Promising Oleaginous Yeast for Olive Mill Wastewater Bioconversion

Energies ◽

10.3390/en14030640 ◽

2021 ◽

Vol 14 (3) ◽

pp. 640

Author(s):

Bruna Dias ◽

Marlene Lopes ◽

Renata Ramôa ◽

Ana S. Pereira ◽

Isabel Belo

Keyword(s):

Phenolic Compounds ◽

Candida Tropicalis ◽

Oxygen Demand ◽

Olive Mill Wastewater ◽

Cellular Growth ◽

Added Value ◽

Organic Load ◽

Batch Cultures ◽

Intracellular Lipids ◽

Olive Mill

Olive mill wastewater (OMW), which is generated during olive oil production, has detrimental effects on the environment due to its high organic load and phenolic compounds content. OMW is difficult to biodegrade, but represents a valuable resource of nutrients for microbial growth. In this study, yeast strains were screened for their growth on phenolic compounds usually found in OMW and responsible for antimicrobial effects. Candida tropicalis ATCC 750 demonstrated an extraordinary capacity to grow in phenolics and was chosen for further experiments with OMW-based medium. The effects of nitrogen supplementation, the pH, and the stirring rate on cellular growth, OMW-components consumption, and added-value compounds production were studied in batch cultures in Erlenmeyer flasks and in a bioreactor. Candida tropicalis was able to reduce 68% of the organic load (chemical oxygen demand) and 39% of the total phenols of OMW in optimized conditions in bioreactor experiments, producing lipase (203 U·L−1) and protease (1105 U·L−1). Moreover, intracellular lipids were accumulated, most significantly under nitrogen-limited conditions, which is common in this type of wastewater. The high potential of C. tropicalis to detoxify OMW and produce added-value compounds from it makes this process an alternative approach to other conventional processes of OMW treatment.

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Structure of Microbial Communities When Complementary Effluents Are Anaerobically Digested

Applied Sciences ◽

10.3390/app11031293 ◽

2021 ◽

Vol 11 (3) ◽

pp. 1293

Author(s):

Ana Eusébio ◽

André Neves ◽

Isabel Paula Marques

Keyword(s):

Anaerobic Digestion ◽

Microbial Communities ◽

Volatile Fatty Acids ◽

Olive Mill Wastewater ◽

Organic Load ◽

Rrna Gene ◽

Bacterial Populations ◽

Next Generation Sequencing Ngs ◽

Generation Sequencing ◽

Olive Mill

Olive oil and pig productions are important industries in Portugal that generate large volumes of wastewater with high organic load and toxicity, raising environmental concerns. The principal objective of this study is to energetically valorize these organic effluents—piggery effluent and olive mill wastewater—through the anaerobic digestion to the biogas/methane production, by means of the effluent complementarity concept. Several mixtures of piggery effluent were tested, with an increasing percentage of olive mill wastewater. The best performance was obtained for samples of piggery effluent alone and in admixture with 30% of OMW, which provided the same volume of biogas (0.8 L, 70% CH4), 63/75% COD removal, and 434/489 L CH4/kg SVin, respectively. The validation of the process was assessed by molecular evaluation through Next Generation Sequencing (NGS) of the 16S rRNA gene. The structure of the microbial communities for both samples, throughout the anaerobic process, was characterized by the predominance of bacterial populations belonging to the phylum Firmicutes, mainly Clostridiales, with Bacteroidetes being the subdominant populations. Archaea populations belonging to the genus Methanosarcina became predominant throughout anaerobic digestion, confirming the formation of methane mainly from acetate, in line with the greatest removal of volatile fatty acids (VFAs) in these samples.

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Ability of the aquatic fern Azolla to remove chemical oxygen demand and polyphenols from olive mill wastewater

Grasas y Aceites ◽

10.3989/gya.2007.v58.i1.6 ◽

2007 ◽

Vol 58 (1) ◽

Cited By ~ 7

Author(s):

Alba Ena ◽

Pietro Carlozzi ◽

Benjamin Pushparaj ◽

Raffaella Paperi ◽

Silvia Carnevale ◽

...

Keyword(s):

Chemical Oxygen Demand ◽

Oxygen Demand ◽

Olive Mill Wastewater ◽

Aquatic Fern ◽

Olive Mill

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Comparison of aerobic processes for olive mill wastewater treatment

Water Science & Technology ◽

10.2166/wst.2020.247 ◽

2020 ◽

Vol 81 (9) ◽

pp. 1914-1926 ◽

Cited By ~ 1

Author(s):

Y. Jaouad ◽

M. Villain-Gambier ◽

L. Mandi ◽

B. Marrot ◽

N. Ouazzani

Keyword(s):

Stable State ◽

Oxygen Demand ◽

Industrial Effluents ◽

Olive Mill Wastewater ◽

Organic Loading Rate ◽

Efficient Technology ◽

Treated Water ◽

Conventional Activated Sludge ◽

Olive Mill

Abstract Membrane bioreactor (MBR) has been proven to be an efficient technology capable of treating various industrial effluents. However, the evaluation of its performances in the case of olive mill wastewater (OMW) over a conventional activated sludge (CAS) have not been determined yet. The present study aims to compare OMW treatment in two laboratory scale pilots: an external ceramic MBR and CAS starting with an acclimation step in both reactors by raising OMW concentration progressively. After the acclimation step, the reactors received OMW at 2 gCOD/L with respect to an organic loading rate of 0.2 and 0.3 kgCOD/kgMLVSS/d for MBR and CAS, respectively. Biomass acclimation occurred successfully in both systems; however, the MBR tolerated more OMW toxicity than CAS as the MBR always maintained an effluent with a better quality. At a stable state, a higher reduction of 95% chemical oxygen demand (COD) was obtained with MBR compared to CAS (86%), but both succeeded in polyphenols removal (80%). Moreover, a higher MLSS elimination from the MBR treated water (97%) was measured against 88% for CAS. Therefore, CAS was suitable for OMW treatment and MBR could be proposed as an alternative to CAS when a better quality of treated water is required.

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Panus tigrinus efficiently removes phenols, color and organic load from olive-mill wastewater

Research in Microbiology ◽

10.1016/j.resmic.2004.04.009 ◽

2004 ◽

Vol 155 (7) ◽

pp. 596-603 ◽

Cited By ~ 62

Author(s):

Alessandro D'Annibale ◽

Marika Ricci ◽

Daniele Quaratino ◽

Federico Federici ◽

Massimiliano Fenice

Keyword(s):

Olive Mill Wastewater ◽

Organic Load ◽

Panus Tigrinus ◽

Olive Mill

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Nanocomposites Photocatalysis Application for the Purification of Phenols and Real Olive Mill Wastewater through a Sequential Process

Applied Sciences ◽

10.3390/app10207329 ◽

2020 ◽

Vol 10 (20) ◽

pp. 7329

Author(s):

Srikanth Vuppala ◽

Marco Stoller

Keyword(s):

Operating Temperature ◽

Oxygen Demand ◽

Olive Mill Wastewater ◽

Light Sources ◽

Sequential Process ◽

Phenol Solution ◽

Aqueous Streams ◽

Flocculation Process ◽

Phenol Wastewater ◽

Olive Mill

In this study, a synthetic phenol solution of water and raw olive mill wastewater (OMW) were considered to achieve purification of the aqueous streams from pollutants. Only OMW was initially submitted to a coagulation/flocculation process, to reduce the turbidity, phenols, and chemical oxygen demand (COD). This first treatment appeared to be mandatory in order to remove solids from wastewater, allowing the successive use of laboratory-made core-shell nanocomposites. In detail, the optimal coagulant concentration, i.e., chitosan, was 500 mg/L, allowing a reduction of the turbidity and the COD value by 90% and 33%, respectively. After this, phenol wastewater was tested for photocatalysis and then OMW was treated by employing the laboratory-made nanocomposites in a photoreactor equipped with visible light sources and using optimal catalyst concentrations, which allowed for an additional 45% reduction of the COD of the OMW. In addition to this, the effect of the operating temperature was investigated on the photocatalytic process, and suitable kinetic models proposed.

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Biodegradation of Olive Mill Wastewater by Trichosporon Cutaneum and Geotrichum Candidum

Archives of Industrial Hygiene and Toxicology ◽

10.2478/10004-1254-61-2010-2079 ◽

2010 ◽

Vol 61 (4) ◽

pp. 399-405 ◽

Cited By ~ 4

Author(s):

Tibela Dragičević ◽

Marijana Hren ◽

Margareta Gmajnić ◽

Sanja Pelko ◽

Dzoko Kungulovski ◽

...

Keyword(s):

Phenolic Compounds ◽

Oxygen Demand ◽

Geotrichum Candidum ◽

Olive Mill Wastewater ◽

Trichosporon Cutaneum ◽

Aerobic Conditions ◽

Wide Range ◽

Dark Colour ◽

Static Conditions ◽

Olive Mill

Biodegradation of Olive Mill Wastewater by Trichosporon Cutaneum and Geotrichum CandidumOlive oil production generates large volumes of wastewater. These wastewaters are characterised by high chemical oxygen demand (COD), high content of microbial growth-inhibiting compounds such as phenolic compounds and tannins, and dark colour. The aim of this study was to investigate biodegradation of olive mill wastewater (OMW) by yeasts Trichosporon cutaneum and Geotrichum candidum. The yeast Trichosporon cutaneum was used because it has a high potential to biodegrade phenolic compounds and a wide range of toxic compounds. The yeast Geotrichum candidum was used to see how successful it is in biodegrading compounds that give the dark colour to the wastewater. Under aerobic conditions, Trichosporon cutaneum removed 88 % of COD and 64 % of phenolic compounds, while the dark colour remained. Geotrichum candidum grown in static conditions reduced COD and colour further by 77 % and 47 %, respectively. This investigation has shown that Trichosporon cutaneum under aerobic conditions and Geotrichum candidum under facultative anaerobic conditions could be used successfully in a two-step biodegradation process. Further investigation of OMW treatment by selected yeasts should contribute to better understanding of biodegradation and decolourisation and should include ecotoxicological evaluation of the treated OMW.

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Extracellular laccase production and phenolic degradation by an olive mill wastewater isolate

Grasas y Aceites ◽

10.3989/gya.0776171 ◽

2018 ◽

Vol 69 (1) ◽

pp. 231 ◽

Cited By ~ 2

Author(s):

R. Kumar ◽

Y. Raizner ◽

L. I. Kruh ◽

O. Menashe ◽

H. Azaizeh ◽

...

Keyword(s):

Gallic Acid ◽

Antimicrobial Agents ◽

Olive Mill Wastewater ◽

Organic Load ◽

Laccase Production ◽

16S Rna ◽

Extracellular Laccase ◽

Acinetobacter Pittii ◽

Constitutive Production ◽

Olive Mill

Olive mill wastewater (OMWW) presents a challenge to the control of effluents due to the presence of a high organic load, antimicrobial agents (monomeric-polymeric phenols, volatile acids, polyalcohols, and tannins), salinity and acidity. In this study, the production of extracellular laccase, monomeric or polymeric phenol, from an OMWW isolate based on its ability to biodegrade phenols and gallic acid as a model of phenolic compounds in OMWW was investigated. Phylogenetic analysis of the 16S RNA gene sequences identified the bacterial isolate (Acinetobacter REY) as being closest to Acinetobacter pittii. This isolate exhibited a constitutive production of extracellular laccase with an activity of 1.5 and 1.3 U ml/L when supplemented with the inducers CuSO4 and CuSO4+phenols, respectively. Batch experiments containing minimal media supplemented with phenols or gallic acid as the sole carbon and energy source were performed in order to characterize their phenolic biodegradability. Acinetobacter REY was capable of biodegrading up to 200 mg/L of phenols and gallic acid both after 10 h and 72 h, respectively.

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Optimization of electrocoagulation operating parameters for COD removal from olive mill wastewater: application of Box-Behnken design

Mediterranean Journal of Chemistry ◽

10.13171/mjc93191011240kea ◽

2019 ◽

Vol 9 (3) ◽

pp. 212-221

Author(s):

Fatima Erraib ◽

Khalid El Ass

Keyword(s):

Response Surface ◽

Chloride Concentration ◽

Oxygen Demand ◽

Olive Mill Wastewater ◽

Operating Conditions ◽

Cod Removal ◽

Coefficient Of Determination ◽

Box Behnken Design ◽

Initial Ph ◽

Olive Mill

Box–Behnken response surface design was successfully employed to optimize and study the olive mill wastewater (OMW) treatment by electrocoagulation (EC) process. The influence of four decisive factors were modelled and optimized to increase the removal of chemical oxygen demand (COD). The Box–Behnken design (BBD) results were analyzed and the second-order polynomial model was developed using multiple regression analysis. The model developed from the experimental design was predictive and a good fit with the experimental data with a high coefficient of determination (R2 ) value (more than 0.98). The optimal operating conditions based on Derringer’s desired function methodology are found to be; initial pH of 4.4, a current density of 27.6 mA/cm2 , electrolysis time of 14.1 min, and chloride concentration of 3.2 g/L. Under these conditions, the predicted COD removal efficiency was found to be 67.14% with a desirability value of 0.94. These experimental results were confirmed by validation experiments and proved that Box–Behnken design and response surface methodology could efficiently be applied for modelling of COD removal from OMW.

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