Physicochemical analysis and adequation of olive oil mill wastewater after advanced oxidation process for reclamation by pressure-driven membrane technology.

Physicochemical characterization of olive mill wastewaters (OMW) was studied after a primary and secondary treatment was implemented in an olive oil factory in Jaén (Spain), comprising natural precipitation, Fenton-like reaction, flocculation-sedimentation and olive stone filtration in series. The application of membrane technology in improving the quality of the secondary-treated OMW (OMW/ST) was examined, to reduce the hazardous electroconductivity (EC) values (2-3 mS cm(-1)). Particle size distribution on OMW/ST shows supra-micron colloids and suspended solids as well as sub-micron particles with a mean size below 1.5 µm remaining in considerable concentration. The high organic pollutants percentage (31.7%) registered with an average diameter below 3 kDa is sensibly relevant for membrane fouling. Mesophilic aerobic bacteria growth warns of possible membrane biofouling formation. The saturation index indicates to work upon recovery factor below 90%. Finally, operating at a pressure equal to 15 bar ensured low fouling and high flux production on the selected NF membrane (69.9 L h(-1)m(-2)) and significant rejection efficiencies (55.5% and 88.5% for EC and COD). This permits obtaining an effluent with good quality according to the recommendations of the Food and Agricultural Association (FAO) with the goal of reusing the regenerated water for irrigation.

A novel photocatalyst with ferromagnetic core used for the treatment of olive oil mill effluents from two-phase production process.

Photocatalytic degradation of olive oil mill wastewater from two-phase continuous centrifugation process was studied. A novel photocatalyst with ferromagnetic properties was characterized and investigated. The degradation capacity of the photocatalytic process of olive oil washing wastewater (OMW) and mixture of olives and olive oil (1 v/v) washing wastewaters (MOMW) was demonstrated. At lab-scale, the %COD removal and residence time (τ) for MOMW and OMW were 58.4% (τ = 2 h) and 21.4% (τ = 3 h), respectively. On the other hand, at pilot scale, 23.4% COD(removal), 19.2% total phenols(removal), and 28.1% total suspended solids(removal) were registered at the end of the UV/TiO2 process for OMW, whereas 58.3% COD(removal), 27.5% total phenols(removal), and 25.0% total suspended solids(removal) for MOMW. Also, before the UV/TiO2 reaction, a pH-T flocculation operation as pretreatment was realized. The overall efficiency of the treatment process for MOMW was up to 91% of COD(removal), in contrast with 33.2% of COD(removal) for OMW.

Changes of the wax contents in mixtures of olive oils as determined by gas chromatography with a flame ionization detector.

Mixing of refined olive-pomace oil with virgin olive oil is a fraud that has been tried often. Normally, the tests that detected the fraud were determinations of wax esters, erythrodiol+uvaol, and stigmastadienes contents. The most common is the determination of wax esters content (extra virgin olive oil is very poor in wax esters, usually less than 100 mg/kg). In this work, the variations of individual wax esters (C40, C42, C44, and C46), with different degrees of unsaturation content, and total wax esters were studied when extra virgin olive oil and refined pomace-olive oil were mixed. The following mixtures were prepared: extra virgin olive oil plus 1, 2, 4, 6, 8, 10, 12, 15, 18, 25, 35, 45, 50, and 80% of refined olive-pomace oil. In all cases, individual and total wax ester content variation was linear with increasing percentage of refined olive-pomace oil in the mixture. The variation of the total wax esters content can be adjusted according to the equation: Total wax esters, mg/kg = 14.3 x (% refined olive-pomace oil) + 83.9.

Changes in phenolic compounds and Rancimat stability of olive oils from varieties of olives at different stages of ripeness.

BACKGROUND: Recently, diets rich in natural foods and food-derived components, such as phenolic compounds, have received a great deal of attention because they are perceived as 'safe' and 'non-medicinal'. In fact, some are known to function as chemopreventive agents against oxidative damage, cerebrovascular disease, and aging. RESULTS: Phenolic compounds, natural antioxidants present in virgin olive oil, play an important role in oil quality by contributing significantly to protecting oil stability against oxidation. In addition, polyphenols are the main contributors to olive oil bitterness, astringency and pungency. The data were fit by linear regression, giving Rancimat stability (h) = 0.18× Total polyphenols (mg L(-1)) in the virgin olive oil. CONCLUSIONS: The practice of harvesting ripe olives as soon as possible to produce oils of high phenolic contents and thus high oxidative stability implies bitter and piquant oils, this being admissible for oils of some varieties but detrimental to others appreciated in the market for being more fruity and sweeter.

Elimination of pesticide residues from virgin olive oil by ultraviolet light: preliminary results.

Virgin olive oil is one of the essential products for the economy of Mediterranean countries. The possible residues of pesticides that can reach the oil may be a risk to public health, thus causing the prohibition of its marketing by the health authorities. This paper is a preliminary study on photochemical degradation of pesticide residues using a small-scale prototype (1L capacity). The method presents an effective alternative for the complete photodegradation or reduction of these chemicals using ultraviolet light without harming the quality parameters of the virgin olive oil. The photodegradation yields have varied within the range 7-80% depending on the time and temperature applied.

Use of industrial wastewater from olive-oil extraction for biomass production of Scenedesmus obliquus.

The use of rinse water (RW) from two-phase centrifugation in the olive-oil extraction industry has been studied in relation to the production of the microalga Scenedesmus obliquus (CCAP 276/3A). The characterization of the wastewater indicates that it is N deficient. The highest value of maximum specific growth rate, 0.044 h(-1) was registered in the culture with 5% RW. However, biomass productivity proved greater in the culture with 100% RW. The specific growth rates were adjusted to a model of inhibition by substrate. The content in normalized chlorophyll diminished with the duration of the cultures, reaching a minimum CHL'(min) value, which showed an inhibition type similar to that of the specific growth rate. The yield in protein indicates that the cultures were limited by N to approximately 50% RW. The greater specific rate of protein synthesis during the exponential phase was 3.7 mg/gh to 50% RW. It was found that the composition of the lipid fraction of the biomass depended on the percentage of wastewater used as the nutrient medium, reaching the highest percentages of monounsaturated, polyunsaturated, and essential fatty acids in the culture with 100% RW.