Effect of blending olive leaves and olive mill wastewater on the potential biogas production

Control of branched broomrape (Orobanche ramosa L.) in tomato (Lycopersicon esculentum Mill.) by olive cake and olive mill waste water

Mediterranean countries are known worldwide for their significant contribution to olive oil production, which generates large amounts of olive mill wastewater (OMW) that degrades land and water environments near the disposal sites. OMW consists of organic substances with high concentrations of phenolic compounds along with inorganic particles. The aim of this study is to assess the effectiveness of satellite image analysis techniques using multispectral satellite data with high (PlanetScope, 3 × 3 m) and medium (Sentinel-2, 10 × 10 m) spatial resolution to detect Olive Mill Wastewater (OMW) disposal sites, both in the SidiBouzid region (Tunisia) and in the broader Rethymno region on the island of Crete, (Greece). Documentation of the sites was carried out by collecting spectral signatures of OMW at temporal periods. The study integrates the application of a variety of spectral vegetation indices (VIs), such as the Normalized Difference Vegetation Index (NDVI), in order to evaluate their efficiency in detecting OMW disposal areas. Furthermore, a set of image-processing methods was applied on satellite images to improve the monitoring of OMW ponds including the false-color composites (FCC), the Principal Component Analysis (PCA), and image fusion. Finally, different classification algorithms, such as the ISODATA, the maximum likelihood (ML), and the Support Vector Machine (SVM) were applied to both satellite images in order to assist in the overall approach to effectively detect the sites. The results obtained from different approaches were compared, evaluating the efficiency of Sentinel-2 and PlanetScope images to detect and monitor OMW disposal areas under different morphological environments.

The disposal of olive mill wastewater (OMW) produced during oil extraction in Mediterranean countries creates a significant environmental problem because of the great volumes of effluent produced (10-12 Mm3 year-1), heavy pollution load (40-80 g L‑1 biological oxygen demand (BOD), 50-150 g L‑1 chemical oxygen demand (COD)) and phytotoxic properties (because of phenolic compounds). During the last 30 years, many OMW treatment methods have been proposed and tested, but their application at the olive mill level is limited because of the high investment and/or running costs and technical expertise required. Existing technologies for OMW management have been identified and evaluated with the LIFE+ OLEICO+ project following certain criteria that are currently being used in Portugal, Spain, Italy and Greece. The results show that several viable technologies for OMW treatment do exist (composting, electro-coagulation, hydrolysis-oxidation, phyto-remediation, co-digestion, energy production); however, they require capital investment and maintenance costs that cannot be afforded by a small or medium olive mill plants. On the other hand, application of OMW to olive orchards can be a low-cost alternative method for OMW treatment in regions with small olive oil mill enterprises. Annual rates up to 1500 L tree-1 were applied in five equal doses, at 20-day intervals between November and February. Soil analyses were performed before the onset and after the end of the OMW application period. The response of olive trees to OMW application was monitored by measuring plant nutritional status, photosynthesis and yield. Furthermore, the possibility of groundwater pollution by the application of fresh OMW was investigated with lysimeters. OMW-treated soil had higher K content throughout the experiment. Phenols were decomposed rapidly, and therefore the phenolic content before the onset of a new OMW application period was negligible. The nutritional status, physiology and yield of olive trees were not affected by the application of OMW. The total olive orchard area required for the annual OMW production was 3.6 ha (280 trees ha-1), which is easily available around an olive mill. The cost of application is €0.007 L‑1 OMW, which seems reasonable compared with more sophisticated methods. Detailed study for each case is required in order to determine the application dose according to soil and climatic conditions of the area. The results show that several viable technologies do exist; however, the implementation cost is not negligible.

Combined bioremediation and enzyme production by Aspergillus sp. in olive mill and winery wastewaters

Mould strains were isolated from Olive Mill Waste (OMW) waters, characterized and screened for their activities on polyphenols hydrolysis by reculturing on the olive mill waste waters itself. The selected strains were then used for polyphenols removal in pure culture assays in flasks. Prior to the inoculation, OMW water was diluted to prepare three initial concentrations of polyphenols (2.2 g/L; 4.5g/L; 14.5g/L). Chemical characteristics including polyphenols and Chemical Oxygen Demand (COD) were followed up in these assays. Results showed that the polyphenols removal by some strains was estimated to around 95.14% and the COD was also decreased by 43%. Olive mill waste waters are normally colored in dark because of the polyphenols oxidation. The microbial strains by hydrolysing the polyphenols had decolored completely these effluents and a clear liquid was obtained afier 12-15 days of treatment under aerobic shaking in laboratory. Polyphenols may have some inhibitory effect which would cause problems to the biological treatment of these effluents. Their removal would facilitate the treatment of the waste.

This paper describes the introduction of olive mill wastewater (OMW) to replace fresh water normally used in clay brick manufacture. OMW is recognised as the major agro‐food industry pollutant in the Mediterranean/North African olive‐growing region. The research involved adding OMW to laboratory‐produced clay bricks following the same making procedure used at a collaborating Tunisian brick factory. The samples containing OMW were found to be comparable in forming/extrusion performance to a control product that used fresh water. If introduced at the factory scale, this innovation would allow a substantial volume of OMW to be recycled, saving on the fresh water currently used in the brick‐forming process. During the subsequent brick drying operation, most of the OMW (∼98% water) would be released as vapour. Once in the kiln, the remaining solids in the bricks (calorific value 21–23 MJ kg−1) would liberate additional heat, reducing the gross energy from fossil fuel currently required during firing. Copyright © 2006 Society of Chemical Industry

Agro-physiological responses of Koroneiki olive trees (Olea europaea L.) irrigated by crude and treated mixture of olive mill and urban wastewaters

This paper discusses decolorization and chemical oxygen demand (COD) abatement in olive mill wastewaters (OMW) by Phanerochaetae chrysosporium grown in static, suspended and immobilised cultures. When P chrysosporium is used in cultures, no decolorization of crude OMW is observed. Decolorization occurs only after removal of polyphenols by adsorption on wood sawdust, which allows for removal of 39% of polyphenols. The use of High lignin peroxides (Lip) producing medium, yields the highest OMW decolorization and COD removal efficiencies. The use of P chrysosporium immobilized on polyurethane foam leads to significant abatements of OMW polluting characteristics. In fact, chemical oxygen demand (COD), Biological oxygen demand (BOD5) and polyphenols contents are significantly reduced. In addition, a significant effluent decolorization is obvious.

Cardiovascular toxicity in cancer patients receiving chemotherapy remains one of the most undesirable side effects, limiting the choice of the most efficient therapeutic regimen, including combinations of different anticancer agents. Anthracyclines (doxorubicin) and antimetabolites (5-fluorouracil (5-FU), capecitabine) are among the most known agents used in breast cancer and other neoplasms and are associated with cardiotoxic effects. Extra-virgin olive oil (EVOO) is rich in polyphenols endowed with antioxidant cardioprotective activities. Olive mill wastewater (OMWW), a waste product generated by EVOO processing, has been reported to be enriched in polyphenols. In this study, we investigated the activities of polyphenol-rich extract from OMWW, A009, in cooperation with chemotherapy on two breast cancer cell lines, namely, BT459 and MDA-MB-231, in a cardio-oncology perspective. The effects of A009 on cardiac cells were also investigated with and without chemotherapeutic agents. Cell viability was determined on BT459 and MDA-MB-231 (i.e., breast cancer cells) and H9C2 (i.e., rat cardiomyocytes) cells, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. A spheroids assay was used as a 3D in vitro model on BT459 and MDA-MB-231 cells. For in vivo studies, the murine sponge assay of angiogenesis was used as a model of breast cancer-associated vascularization. The embryo of Danio rerio (zebrafish) was used to detect the cardioprotective activities of the OMWW. We found that the A009 extract exhibited antiangiogenic activities induced by breast cancer cell supernatants and increased T-cell recruitment in vivo. The combination of the OMWW extracts with doxorubicin or 5-FU limited BT459 and MDA-MB-231 cell viability and the diameter of 3D spheroids, while mitigating their toxic effects on the rat H9C2 cardiomyocytes. Cardioprotective effects were observed by the combination of OMWW extracts with doxorubicin in zebrafish embryos. Finally, in human cardio myocytes, we observed 5-FU-induced upregulation of the inflammatory, senescence-associated cytokine IL6 and p16 genes, which expression was reduced by OMWW treatment. Our study demonstrates that the polyphenol-rich purified OMWW extract A009 combined with cancer chemotherapy could represent a potential candidate for cardiovascular protection in breast cancer patients, while increasing the effects of breast cancer chemotherapy.

Olive oil mill wastewater toxicity in the marine environment: Alterations of stress indices in tissues of mussel Mytilus galloprovincialis

The current study was aim to remediate olive mill waste water (OMWW) to reduce its phenol content and Chemical Oxygen Demand (COD) using fungal isolates. OMWW samples were drawn from the outlet of olive presser at Agriculture Research center, Egypt and characterized. Inoculating 25% diluted waste sample on Potato dextrose agar plates, incubated for 2 weeks at 25oC, resulted in 8 fungal isolates, of which isolate 5 was selected based on its capabilities to degrade phenol and reduce COD, compared to the rest of the obtained isolates. Comparison was conducted between the selected isolate and the fungus Pleurotus columbinus as a reference to test their potencies to degrade phenol and reduce COD in OMWW at concentrations from 100 to 10% over 4 weeks and results showed low degradability and weak tolerance of the two organisms at concentrations from 50 to 100%, while at 40, 30, 20 and 10%, phenol degradation and COD reduction over the 4 weeks treatment were more obvious. At all concentrations P. columbinus showed better competency for phenol degradation and COD reduction than isolate 5. Decolorization and growth of the two organisms were investigated in OMWW at 40 to 10% concentrations. P. columbinus, again, showed better competency over isolate 5 where it 79 and 49% of the color were removed after 4 weeks by P. columbinus and isolate 5, respectively. Total carbohydrate was also determined in the treated OMWW over 4 weeks and results showed it decreased from 6.05 to 5.2g/L in 40% OMWW and from 4.27 to 3.6 g/L in 30% OMWW, while it increased from 3.1 to 4.37g/L in 20% OMWW and from 1.46 to 3.9 g/L in 10% OMWW. Finally, the presence of indol acetic acid and gibberellins in 20 and 10% OMWW was tested as affect by the treatment with P. columbinus over the period of 4 weeks.Results showed that, after 4 weeks, IAA content decreased from 29.4 to 23.25 µg/ml in 20% OMWW, and slightly from 15.6 to 13,15 µg/ml in 10% OMWW. For gibberellins, the change after 4 weeks in 20% OMWW was not significant, that it decreased from 1.36 to 1.25mg, while it increased from 0.667 to 1.58 mg/ml in 10% waste in the same period. It can be concluded that remediating OMWW with P. columbinus can achieve a better results and the treated waste may be suitable for irrigation of crops.

Ultrasound pretreatment for enhanced biogas production from olive mill wastewater

The aim of the present study was to investigate the antioxidant effects of a feed supplemented with polyphenolic additives from olive mill wastewater (OMW) on lambs. Lambs received breast milk until the postnatal period, and then they were divided into two groups and received control and OMW feed for 55 days. Redox biomarkers were measured in blood and tissues at days 15, 42 and 70 after feeding. Feed supplemented with OMW reduced thiobarbituric acid reactive species and protein carbonyls and increased total antioxidant capacity, glutathione and catalase activity in both blood and tissues. The administration of OMW-containing feed reinforced the antioxidant defense of lambs, which may improve their wellbeing and productivity. Additionally, this exploitation of OMW may solve problems of environmental pollution in areas with olive oil industries.

This paper discusses decolorization and chemical oxygen demand (COD) abatement in olive mill wastewaters (OMW) by Phanerochaetae chrysosporium grown in static, stirred and immobilized cultures. When P. Chrysosporium is used in cultures, no decolorization of crude OMW is observed. Decolorization occurs only after the removal of polyphenols by adsorption in sawdust, which allows a 39% polyphenol removal. The use of a High lignin peroxides (Lip) producing medium, yields the highest OMW decolorization and COD removal efficiencies. The use of P. Chrysosporium immobilized on polyurethane foam leads to significant abatements of OMW polluting characteristics. And COD abatement reached 70%. The reduction of polyphenols reached its highest level at 62%. A significant effluent decolorization is apparent.

The traditional olive oil extraction process generates a large amount of liquid by-product that could be recycled as an organic fertilizer. The aim of this 3-year field experiment was to assess the effects of olive mill wastewater (OMWW) application on yields of ryegrass, proteic pea, and clover crops and on soil properties. The following treatments were compared: OMWW at 80 m3 ha−1 (80_OMWW), OMWW at 120 m3 ha−1 (120_OMWW), and an unfertilized control (Contr). The yields of ryegrass increased 40% and 41.6% compared to Contr, for 80_OMWW and 120_OMWW, respectively, while a significant enhancement was found at the lowest level of OMWW in proteic pea (27.0% increase). Clover showed a species-specific sensitiveness, but the OMWW applications increased the protein content 26.3% and 28.7% for 80_OMWW and 120_OMWW, respectively, in comparison with Contr. The OMWW rates also enhanced the total organic content in the soil compared to the unfertilized control. At the end of the 3-year experiment, total extracted carbon and humified organic carbon were greater than the initial ones. The values of available phosphorus (P) and potassium (K) determined at the end of experiment in Contr were almost the same as those recorded at the beginning of the research, confirming that the increases found in 80_OMWW and 120_OMWW plots were due to the OMWW applications. The findings suggest that repeated applications of OMWW could both sustain fodder crop performance and support soil fertility, with the possibility to recycle the organic amendment and reduce the risks of soil degradation.