Olive Mill Wastewater Research Articles

From Waste to Health: Olive Mill Wastewater for Cardiovascular Disease Prevention.

Waste from the agri-food chain represents a valuable reservoir of organic compounds with health-promoting properties. Momast Plus 30 Bio (MP30B) is a derivative obtained from olive-oil wastewater. Its enrichment in hydroxytyrosol (HT) via a patented technique has paved the way for its potential application as a dietary supplement in preventing cardiovascular diseases. MP30B demonstrates no significant alteration in cardiac and vascular parameters in "ex vivo" studies. However, it exhibits a strong ability to remove reactive oxygen species and exerts anti-inflammatory effects, notably reducing the concentration of iNOS and mitigating heart infections in "in vitro" experiments. Furthermore, MP30B slightly decreases the stiffness of the "ex vivo" thoracic aorta, potentially resulting in lowered arterial pressure and enhanced energy transfer to a normal ventricle. Based on these findings, we posit MP30B as a promising extract for cardiovascular disease prevention, and its specific antibacterial properties suggest its utility in preventing cardiac infections.

Novel eco-friendly and easily recoverable bismuth-based materials for capturing and removing polyphenols from water

Olive oil production is one of the most developed Europe's sectors, producing olive oil and undesirable by-products, such as olive mill wastewater (OMWW) and organic waste. OMWW, containing large amounts of compounds (mainly polyphenols, phenols, and tannins), represents a problem. In fact, polyphenols have dual nature: i) antioxidant beneficial properties, useful in many industrial fields, ii) biorefractory character making them harmful in high concentrations. If not properly treated, polyphenols can harm biodiversity, disrupt ecological balance, and degrade water quality, posing risks to both environment and human health. From a circular economy viewpoint, capturing large quantities of polyphenols to reuse and removing their residuals from water is an open challenge. This study proposes, for the first time, a new path beyond the state-of-the-art, combining adsorption and degradation technologies by novel, eco-friendly and easily recoverable bismuth-based materials to capture large amounts of two model polyphenols (gallic acid and 3,4,5-trimethoxybenzoic acid), which are difficult to remove by traditional processes, and photodegrade them under solar light. The coupled process gave rise to collect 98% polyphenols, and to rapidly and effectively photodegrade the remaining portion from water.

Adsorbents Produced from Olive Mill Waste and Modified to Perform Phenolic Compound Removal

Olive mill waste (olive pomace, OP, and olive stone, OS) was used in this work to produce adsorbents for the removal of five phenolic acids typically found in olive mill wastewater. OP and OS were subjected to different treatments (combined or not) that were chemically modified (NaOH) or physically modified by two different methods, incipient wetness impregnation (IWI) and hydrothermal deposition (HD), and even biochar production obtaining a total of 16 materials. The materials were characterized by different analytical techniques such as N2 absorption, scanning electron microscopy, infrared spectroscopy, and pH zero-potential charge. The mixture of five phenolic acids was used to evaluate in batch conditions the adsorption capacity of the prepared materials. OS chemically modified with IWI (OSM-IWI) and OS biochar with HD (BOS-HD) presented better adsorption capacity at 157.1 and 163.6 mg/g of phenolic acids, respectively, from a total of 200 mg/g. For some materials, the surface area cannot be correlated with adsorption capacity, unlike pHzpc, where high values fit better adsorption rates. The infrared spectroscopy profile indicates the presence of O-H and N-H functional groups and, the last one, red-shifted in the IWI preparation compared to the HD one. In addition to this, the prepared material from olive mill waste can be suitably used for the mixture of phenolic compounds.

Phenolic compounds, chemical oxygen demand and total carbon organic removal from olive mill wastewater by activated persulfate oxidation using full factorial design

Abstract This study investigated phenolic compounds (PC), chemical oxygen demand (COD) and total carbon organic total (TOC) removal from olive mill wastewater OMW via activated persulfate oxidation. Persulfate (PS, S 2 O 8 2 − ${\mathrm{S}}_{2}{\mathrm{O}}_{8}^{2-}$ ) was activated by thermal and transition metal to form sulfate radical ( S O 4 · − $\mathrm{S}{\mathrm{O}}_{4}^{{\cdot}-}$ ). A mathematical model was developed, and the process variables, namely oxidant dose (0.05 and 0.1 g L−1), type of catalyst (Fe2+, Cu2+), time of treatment (5 and 20 min) and temperature (25 and 45 °C) and their interaction were examined using a full factorial design methodology 24. The results indicated that activation methods are efficient for reduction of PC and COD in OMW. Under conditions maximizing responses, there was a considerable increase in PC, COD and TOC removal (44.73 %, 62.39 % and 95.13 % respectively). The correlation coefficient values of the polynomial model were found to be 90 % (CP removal) and 86 % (COD removal). The predicted values obtained using the response functions agreed well with the experimental data.

An innovative method to remove phenols from olive mill wastewater using heterogeneous modified polyacrylonitrile (PAN) catalyst

ABSTRACT Phenolic compounds contained in olive oil mill wastewater (OMW) cause environmental issues when left untreated. A novel heterogeneous surface functionalised nanocoated polyacrylonitrile (PAN) mesh used as a Fentons' catalyst acting with hydrogen peroxide gave 70–100% phenol reduction and an average total organic carbon (TOC) reduction of 64.7% when seven phenols as described below were individually treated (100 mg/L phenolic, 500 mg/L H2O2, 12 g catalyst, 20 °C). As a mixture of seven phenols (100 mg/L of each, 12 g catalyst, 3,500 mg/L H2O2), such as trans-cinnamic acid, p-coumaric acid, caffeic acid, vanillic acid, ferulic acid, tyrosol and hydroxytyrosol, there was 77.5% phenol and 43.9% TOC reduction. The addition of UVc light (100 mg/L phenolic, 500 mg/L H2O2, 12 g catalyst, 20 °C, UV flux 2.66 mW/cm2) significantly improved the degradation of the initial phenolic concentration by 98% in the individual treatments. A pH of 3 and a temperature of 30 °C were found to be the most effective and efficient. The fresh and regenerated catalysts were both recycled over 10 cycles before deactivation which shows promise for continuous flow and scale-up for use as an OMW treatment.

Olive mill wastewater as booster to produce a blood orange juice with high healthy value

Olive mill wastewater as booster to produce a blood orange juice with high healthy value

Applying the experiment design approach to minimize pollutants in olive mill wastewater using aluminum sulfate and ferric chloride as coagulants. West Bank—occupied Palestinian territories

A significant environmental contaminant in the West Bank and the Mediterranean Basin is olive mill wastewater (OMWW). OMWW was released between mid-September and mid-November, when harvesting was taking place. This led to environmental issues with soil, water resources, and the ecology. The optimization of the removal of organic compounds as total suspended solids (TSS), chemical oxygen demand (COD), and total polyphenols group (TP) pollutants is the main goal of this study. Both aluminum sulfate (AS) and ferric chloride (FC) are utilized as coagulants. The ideal dosages, coagulant types, and pH values to reduce the concentration of these pollutants were determined using the Design of Expert program (DoE). For the AS and FC, the optimal pH range is between 4 and 5, which reduces the TSS by roughly 93 % and 80 %, respectively. By using AS and FC, respectively, COD was removed at rates of 68 % and 58 %, and 0.5 g/l was the ideal coagulant concentration dose. The most important factor affecting the elimination procedure was the pH level. The outcomes show that those three contaminants can be successfully eliminated by the coagulation process. TSS ranges between 90 % and 96 %, COD between 53 % and 73 %, and TP between 11 % and 37 % when the two coagulate salts are used

Olive Mill Wastewater Extract: In Vitro Genotoxicity/Antigenotoxicity Assessment on HepaRG Cells.

Olive mill wastewater (OMWW), with its high level of phenolic compounds, simultaneously represents a serious environmental challenge and a great resource with potential nutraceutical activities. To increase the knowledge of OMWW's biological effects, with an aim to developing a food supplement, we performed a chemical characterisation of the extract using the Liquid Chromatography-Quadrupole Time-of-flight spectrometry (LC-QTOF) and an in vitro genotoxicity/antigenotoxicity assessment on HepaRG ™ cells. Chemical analysis revealed that the most abundant phenolic compound was hydroxytyrosol. Biological tests showed that the extract was not cytotoxic at the lowest tested concentrations (from 0.25 to 2.5 mg/mL), unlike the highest concentrations (from 5 to 20 mg/mL). Regarding genotoxic activity, when tested at non-cytotoxic concentrations, the extract did not display any effect. Additionally, the lowest tested OMWW concentrations showed antigenotoxic activity (J-shaped dose-response effect) against a known mutagenic substance, reducing the extent of DNA damage in the co-exposure treatment. The antigenotoxic effect was also obtained in the post-exposure procedure, although only at the extract concentrations of 0.015625 and 0.03125 mg/mL. This behaviour was not confirmed in the pre-exposure protocol. In conclusion, the present study established a maximum non-toxic OMWW extract dose for the HepaRG cell model, smoothing the path for future research.

Waste Biomass Pretreatments for Biogas Yield Optimization and for the Extraction of Valuable High-Added-Value Products: Possible Combinations of the Two Processes toward a Biorefinery Purpose

Second- and third-generation biorefineries enable the sustainable management of biomasses within the framework of circular economy principles. This approach aims to minimize waste biomass while generating high-value molecules and bio-energy, such as biogas. Biogas production is achieved via anaerobic digestion, a process where microorganisms metabolize organic compounds in the absence of oxygen to primarily produce CO2 and CH4. The efficiency of this process is closely linked to the composition of the biomass and, sometimes, characteristics of the initial matrix can impede the process. To address these challenges, various pretreatments are employed to enhance digestion efficiency and mitigate issues associated with biomass complexity. However, the implementation of pretreatments can be energy-intensive and costly. The extraction of valuable molecules from biomass for various applications can represent a form of pretreatment. This extraction process selectively removes recalcitrant molecules such as lignin and cellulose, which can hinder biodegradation, thereby adding new value to the biomass. These extracted molecules not only contribute to improved anaerobic digestion efficiency but also offer potential economic benefits by serving as valuable inputs across diverse industrial sectors. This article presents a detailed state of the art of the most widespread biomass pretreatments and specifies when biomass is pretreated to improve the biogas yield and, in contrast, when it is treated to extract high-added-value products. Finally, in order to define if the same treatment can be simultaneously applied for both goals, an experimental section was dedicated to the production of biogas from untreated olive mill wastewater and the same biomass after being freeze-dried and after the extraction of polyphenols and flavonoids. The use of pretreated biomass effectively improved the biogas production yield: the untreated olive mill wastewater led to the production of 147 mL of biogas, while after freeze-drying and after polyphenols/flavonoids extraction, the production was, respectively, equal to 169 mL and 268 mL of biogas.

Innovative utilization of olive mill wastewater phenolics extracted by lecithin: spray-dried powders in cake formulations

In the present study, the olive mill wastewater (OMW) phenolics were extracted with soy lecithin using the cloud point extraction method, and this enriched lecithin (OMW-L) was converted into spray-dried powders using maltodextrin (MD) and whey protein concentrate to be utilized as a dry food ingredient in a cake premix. The inlet temperature of 170 °C and a 3 mL/min feed flow rate yielded the highest powder yield (70.88 ± 2.12%) with a moisture content of 3.78 ± 0.03% when the mass ratio of lecithin to MD was 1:3 (w:w). The hydroxytyrosol and tyrosol contents of the powder were 42.60 ± 4.51 mg/100 g and 15.48 ± 2.50 mg/100 g, respectively. Vanillic acid, caffeic acid, 3-hydroxybenzoic acid, catechin, and rutin were also identified in the powders. The spray-dried OMW-L powder with a higher loading of polyphenols was then used in a cake premix, replacing 1% and 3% of wheat flour. This substitution significantly reduced the K value of the cake batter, as determined by rheological analyses. The addition of spray-dried OMW-L powder to the cake samples, particularly at higher concentrations (3%), influenced both crust and crumb color, causing changes in L*, a*, and b* values. The hardness values of the cake samples did not alter when blank or OMW-enriched lecithin powders were added; rather, the hardness value was influenced by the powder content. Overall, this research offers a different perspective on the use of OMW phenolics in food applications, especially in ready-to-use blends, and demonstrates the effects of the obtained spray-dried lecithin powders on batter rheology and cake characteristics.Graphical abstract

Enhancing Soil Stability through Innovative Microbial-Induced Calcium Carbonate Techniques with Sustainable Ingredient

Expansive soil poses significant challenges for civil engineers, leading to structural damage, particularly in lightly loaded structures. This study employs an innovative and sustainable recipe to stabilize highly expansive soil using the Microbial-Induced Calcium Carbonate Precipitation (MICP) technique by substituting conventional ingredients with olive mill wastewater and hydrated lime. A series of laboratory tests were performed to evaluate the improvement in Atterberg's limits, Free Swell, Unconfined Compressive Strength (UCS), and pH, in addition to a series of qualitative measurements, including X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Optical Microscopic Images, and bacteria growth rate. Different mellowing periods and different cementation concentrations were used. The proposed recipe results showed a 50% reduction in the soil's free swell value. The UCS of the treated soil using the proposed recipe was eight times that of the untreated soil and twice that of the soil treated with the traditional recipe. The SEM images showed flocculation and aggregation in the soil particles, with the voids becoming smaller and filled with calcium carbonate (CaCO3). The XRD results showed the formation of new CaCO3particles. The optimized recipe demonstrated remarkable enhancement improvement and significant changes in soil physical properties and microstructure. Doi: 10.28991/CEJ-2024-010-08-08 Full Text: PDF

Addition of olive by-product extracts to sunflower oil: Study by 1H NMR on the antioxidant effect during potato deep-frying and further in vitro digestion

Potatoes were fried in sunflower oil enriched or not with Chetoui olive by-product extracts (leaves and olive mill wastewater), and afterwards submitted to in vitro gastrointestinal digestion. Frying oils and fried potato lipids before and after digestion were analyzed using proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. Potential differences on lipid composition, oxidative status and after digestion also lipolysis degree, were studied. During deep-frying with oil replenishment, a higher generation of aldehydes was observed in non-enriched oils. During digestion, in the lipids of digested potatoes fried in non-enriched oil a higher degradation of linoleic chains and a higher generation of cis,trans-hydroperoxy- and cis,trans-hydroxy-octadecadienoates (primary oxidation compounds) and of alkanals was observed. A slightly higher lipolysis degree was reached in the lipids of potatoes fried in enriched oils. These findings suggest that the addition of both extracts could exert a potential antioxidant effect during frying and digestion, enhancing the quality, safety and nutritional value of fried food.

Developing Organic Fertilizer Through Co-Composting Olive Mill Wastewater

Developing Organic Fertilizer Through Co-Composting Olive Mill Wastewater

Efficient CO2 capture using a novel Zn-doped activated carbon developed from agricultural liquid biomass: Adsorption study, mechanism and transition state

A Zn-doped carbon was prepared and used as an effective CO2 adsorbent. This carbonaceous material was developed from olive mill wastewater (OMWW) by an innovative process using thermal shock flash pyrolysis followed by zinc chloride impregnation at ambient temperature. The developed Zn-doped carbon is highly porous (1406.56 m2.g−1), thermally stable and rich in active sites. The Temkin isotherm and the pseudo-second order kinetic model best describe the adsorption of CO2 on the developed material, and the storage capacity is of 370.41 mg g−1 (293 K). Thermodynamic parameters showed favorable, exothermic, and orderly adsorption. Two new isotherms, based on the number of layers formed at the surface, developed by advanced statistical modelling, were adapted and used to understand the mechanism in depth. The analysis of the results showed that CO2 adsorption occurs through the appearance of double layers on the adsorbent surface. Adapted models showed: only one molecule was adsorbed per surface active site, a very low degree of aggregation of CO2 molecules before adsorption and the molecules were adsorbed in a parallel orientation. The activation parameters showed a rapid and physical adsorption with a drop in entropy at the transition state. The mechanisms involved were governed by thermodynamic control with the possibility of easy desorption at high temperature. Zn-doped carbon is an ecological approach to reduce CO2 emissions on the globe.

Biotechnological Innovations Unleashing the Potential of Olive Mill Wastewater in Added-Value Bioproducts.

Byproducts and wastes from the food processing industry represent an important group of wastes generated annually in large quantities. It is important to note that the amount of this waste will increase with industrialization, and effective solutions must be found urgently. Many wastes that cause environmental pollution are evaluated by their low-tech conversion into products with little economic value, such as animal feed and fertilizer. Therefore, the evaluation of food processing waste using effective recycling techniques has become an interesting subject with increasing population, ongoing biotechnological studies, and advances in technology. The conversion of food waste into biotechnological products via fermentation is a sustainable, environmentally friendly, and economical method in line with the principles of green chemistry. This approach promotes the reuse of food waste by supporting the principles of a circular economy and offers sustainable alternatives to fossil fuels and synthetic chemicals. This contributes to reducing the carbon footprint, preserving soil and water quality, and providing economic sustainability through the production of high-value products. In this study, the properties of olive mill wastewater, an important and valuable waste in the olive oil industry, its environmental aspects, and its use in biotechnological applications that integrate green chemistry are evaluated.

Mechanosynthesis, characterization, and adsorptive properties of Mg–Al-LDH and Zn–Al-LDH for olive mill wastewater treatment

Mechanosynthesis, characterization, and adsorptive properties of Mg–Al-LDH and Zn–Al-LDH for olive mill wastewater treatment

Impact of Rice Straw and Biochar Compost Treated with Olive Mill Wastewater on some Sandy Soil Properties, Nutritional Status and Yield Productivity

Impact of Rice Straw and Biochar Compost Treated with Olive Mill Wastewater on some Sandy Soil Properties, Nutritional Status and Yield Productivity

Influence of Oleacein, an Olive Oil and Olive Mill Wastewater Phenolic Compound, on Caenorhabditis elegans Longevity and Stress Resistance.

Oleacein, a bioactive compound of olive oil and olive mill wastewater, has one of the strongest antioxidant activities among olive phenolics. However, few reports explore the in vivo antioxidant activity of oleacein, with no clear identification of the biological pathway involved. Earlier studies have demonstrated a link between stress resistance, such as oxidative stress, and longevity. This study presents the effects of oleacein on Caenorhabditis elegans mean lifespan and stress resistance. A significant lifespan extension was observed with an increase of 20% mean lifespan at 5 µg/mL with a hormetic-like dose-dependent effect. DAF-16 and SIR-2.1 were involved in the effects of oleacein on the longevity of C. elegans, while the DAF-2 receptor was not involved. This study also shows the capacity of oleacein to significantly enhance C. elegans resistance to oxidative and thermal stress and allows a better understanding of the positive effects of olive phenolics on health.

Accumulation of heavy metals from single and combined olive mill wastewater and pomace in soil and bioaccumulation in tissues of two earthworm species: Endogeic (Aporrectodea trapezoides) and Epigeic (Eisenia fetida).

Soil and earthworms are threatened by anthropogenic contamination resulting from olive mill waste dumping on the soil due to their pollutant properties. While several studies have explored the effects of olive mill waste on soil properties and the accumulation of heavy metals in soil, there is currently a gap in the literature regarding the potential bioaccumulation of heavy metals from olive mill waste in earthworms. In this study, soil with earthworms from two ecological categories (endogeic: Aporrectodea trapezoides and epigeic: Eisenia fetida) was treated with increasing doses of olive mill wastewater (OMWW) and olive mill pomace (OMP), applied individually or combined, in an indoor experiment in plastic containers, under laboratory conditions. The results revealed the presence of significant concentrations of heavy metals in the two types of wastes ranging as follows: Fe˃ Zn˃ Cu˃ Cd˃ Cr for OMWW, and Fe˃ Zn˃ Cu˃ Cr for OMP (with Cd below the detection limit). The study demonstrated distinct effects of OMWW and OMP, both individually and in combination, on soil heavy metal content, ranging as follows: soil OMWW > soil Combination > soil OMP for Cd; soil Combination > soil OMWW > soil OMP for Cr and Fe; and soil Combination > soil OMP > soil OMWW for Cu and Zn. Additionally, our investigation showed that both earthworm species exhibited significant uptake of these metals into their tissues, particularly the endogeic species. Interestingly, the most significant difference between species was in the accumulation of Cu, with the epigeic species accumulating significantly lower amounts.

Control of Olive Tuberculosis Trees with Olive Mill Wastewater: Inhibition of Pseudomonas savastanoi Adhesion

Control of Olive Tuberculosis Trees with Olive Mill Wastewater: Inhibition of Pseudomonas savastanoi Adhesion