ES2634333A1 - Procedure for the treatment of waste and obtaining of byproducts from almazaras (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Procedure for the treatment of waste and obtaining by-products from oil mills. The present invention relates to a process for treating waste from mills and obtaining by-products of industrial interest, comprising a stage of mixing solid and liquid waste that contributes to improving the extractive process, an extraction stage and a solid separation stage. -liquid. In this way, a solution is offered to the problem posed by the by-products or solid and liquid residues of the oil mills, allowing to valorise the polluting residues of the discharges. (Machine-translation by Google Translate, not legally binding)

Description

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In this regard, membrane technology, which comprises microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (OI), can offer a number of advantages compared to conventional separation processes, erecting it in a very promising technology for the purpose of recovering the polyphenolic fraction contained in the wastewater of the oil industry and the remediation of these effluents.

Among the important advantages of membrane technology we can highlight that it is a green and clean technology since it does not involve the use of chemical reagents, such as solvents, to achieve separation and concentration; its lower capital and energy consumption costs than most conventional separation processes, but still guaranteeing a high purification capacity, selectivity and recovery factor; and also easy industrial scaling by virtue of its modular nature, as well as its simple design and operation, and low maintenance requirements. In addition, the membrane processes can be projected for the recovery of specific compounds, by appropriate selection of the membrane material and suitable pore size, and for this purpose they can also be superficially charged depending on the pH of the solution, adding this way to the exclusion by steric impediment a selectivity factor by effect of electrostatic charge very relevant.

A process for the reduction of the high organic load of the three-phase alpechin was proposed by [Borsani, R., Ferrando, B., 1996. Ultrafiltration plant for olive vegetation waters by polymeric membrane batteries. Desalination 108, 281-286], consisting of a first stage of removal of suspended solids and oil, tangential ultrafiltration (polysulfone membrane of cut size of 30 kDa) and finally a double stage biological treatment, achieving an average reduction of the Biological oxygen demand (BOD5) and chemical oxygen demand of 65 -70% (COD). Another process of treatment of the three-phase vegetable water [Turano, E., Curcio, S., De Paola, MG, Calabrò, V., Iorio, G., 2002. An integrated centrifugation– ultrafiltration system in the treatment of olive mill wastewater . J. Membr. Sci. 206, 519531] consists of an integrated centrifugation system - for the reduction of suspended solids - followed by ultrafiltration (17 kDa polysulfone membrane), reaching up to 80% and 90% overall reduction of solids concentration in suspension and COD, respectively. Some preliminary studies with membranes for the recovery of low molecular weight polyphenolic compounds have already been

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proposed: [Cassano, A., Conidi, C., Giorno, L., Drioli, E., 2013. Fractionation of olive mill wastewaters by membrane separation techniques. J. Hazard Mater. 248, 185–193], [Garcia-Castello, E., Cassano, A., Criscuoli, A., Conidi, C., Drioli, E., 2010. Recovery and concentration of polyphenols from olive mill wastewaters by integrated membrane system . Water Res. 44, 3883–3892], [Conidi, C., Mazzei, R., Cassano, A., Giorno, L., 2014. Integrated membrane system for the production of phytotherapics from olive mill wastewaters. J. Membr. Sci. 454, 322–329], [Paraskeva, C.A., Papadakis, V.G., Tsarouchi, E., Kanellopoulou, D.G., Koutsoukos, P.G., 2007. Membrane processing for olivemill wastewater fractionation. Desalination 213, 218-229]. As a counterpoint, both processes showed a rapid and irreversible clogging of the membranes, which causes them to decrease their productivity and therefore seriously compromise the economic viability of the process.

In patent applications EP 1773721 B1 and WO 2008/067976 A1, the recovery of chemical compounds from the wastewater of the olive industry is proposed through a pH adjustment step followed by enzymatic hydrolysis, separation of particles and suspended solids to obtain a clarified liquid product, and finally the treatment thereof by microfiltration (preferably with 23-channel ceramic membranes, pore size between 0.1-1.4 µm), ultrafiltration (preferably with polymeric polysulfone membranes, regenerated cellulose acetate or polyethersulfone-polyamide, spiral, of molecular size between 1 -20 kDa), nanofiltration (preferably with polymeric membranes cutting size between 150 and 250 Da, in spiral configuration) and reverse osmosis (preferably with polymeric membranes of composite polyamide, of high saline rejection, in spiral configuration), resulting in a retained phase rich in polyphenols and ag ua purified as permeate.

The application EP 2044848 A1 describes a process of treatment of the residual water of vegetation of the alpeorujo of two phases, to recover a polyphenolic concentrate and purified water by means of mechanical separation processes combined with membranes. The proposed process includes de-humidification of the alpeorujo by horizontal centrifugation (until reducing the humidity to 40 -55%) and extraction of the residual oil with organic solvents (hexane), after which additives and / or flocculants are added to facilitate the separation of the solid phase from the liquid by sedimentation, horizontal and / or vertical centrifugation and filtration, and finally

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ultrafiltration (between 50 and 60 ° C) and nanofiltration, all of them finished in diafiltration, and finally biological oxidation.

EP 2338500 A1 proposes a process for obtaining a concentrated solution or powder consisting of different biologically active compounds (such as oleuropein, hydroxytyrosol, verbacoside and anthocyanin pigments) from residues of the olive industry, in particular leaves and pruning residues, olive pulp and pomace, by integrating simple cold or hot or pneumatic extraction (preferably with hydro-alcoholic solutions, between 60 and 95 ° C), followed by separation by microfiltration membranes (polymeric membranes of polysulfone, regenerated cellulose acetate or nylon in spiral configuration, or alumina tubular ceramics internally covered with zirconia or titanium dioxide, pore size between 0.1-3 µm, with between 8 and 85 channels, operating temperature between 45 and 50 ° C, pressure between 5 and 6 bar), ultrafiltration (preferably with spiral membranes, with a cut size between 0.5 -50 kDa), nanofiltration (size of cut between 150 and 250 Da, in spiral configuration) and reverse osmosis (in spiral configuration, with high or low salinity, preferably a maximum of 35 bar operating pressure and up to 60 ° C temperature, with light size spacers between 0 , 51 -0.97 mm), finally completed with a stage of refinement of the concentrates of the UF and NF stages by chromatographic resins

EP 2526785 A1 describes a process for obtaining an extract rich in biologically active compounds of high molecular weight (> 500 Da) from the vegetation water and the olive mill pomace. The method combines physical-chemical and enzymatic pretreatment methods, microfiltration membrane technology (tubular ceramic pore size membranes between 0.1-1.4 µm, with between 8 and 85 channels, operating temperature between 45 and 50 ° C, pressure between 5 and 6 bar) and finally vacuum evaporation, obtaining an extract characterized by a specific composition and properties for application in the fields of the cosmetic, food and phytotherapy industries.

The patent ES 2277490 B1 describes a process of industrialization of fresh alpeorujo by dehydration by centrifugation (between 35 and 45 ° C for 40-60 minutes), from which the liquid fraction is centrifuged to separate solids and obtain a gross alpeorujo for its submission by centrifugation, biological treatment, alcoholic fermentation and filtration, and finally it is concentrated by means of a multiple evaporator

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Vacuum effect (85 ° C), obtaining a concentrate for multiple applications, and on the other hand condensed water that is subjected to a volatile scrubber column to separate alcohol from water, which will finally be purified by means of scrubber columns.

In another patent, ES 2374 675 B1, a device and method for the treatment and use of by-products of obtaining olive oil (alpeorujo or pomace), comprising a preheating (between 100 and 200 ° C for a maximum of 180 minutes) of them and subsequent introduction into a reactor for direct heating with water vapor (pressure between 3 and 11 bar) and / or indirectly through a heating wall, and extraction of the volatile phase by condensation, and then a separation is carried out in a three-phase horizontal centrifuge.

In WO 2006/005986 A1 a process for obtaining a concentrate in oleic polyphenols of solid or semi-solid sub-products of oil mills using a polar solvent is detailed (maximum temperature 85 ° C for 3 to 5 hours, by-product / solvent ratio of 1/3 to 1/30) and enzymatic hydrolysis (with esterase and βglucosidase, temperature between 50 and 60 ° C, pH between 4 and 6.5), followed by the extraction of polyphenols from said mixture and subsequent concentrate of the solution by ultrafiltration medium (pore size between 0.01-0.1 µm) and nanofiltration (hollow fiber or spirals, pore size between 1-10 nm) and finally vacuum distillation and spray-dry drying (maximum temperature 70 ° C).

WO 2007/013032 A2 proposes a process for obtaining a concentrate rich in hydroxytyrosol from the residues and solid by-products of the olive grove, through an initial stage of extraction preferably with hydroalcoholic mixtures, followed by another subsequent stage of fluid extraction supercritical (with supercritical CO2 at a temperature between 30 and 80 ° C and pressure between 8 and 20 MPa), combined with nanofiltration (average membrane pore size of 300 Da, operating pressure between 1.0 -1.5 MPa) and reverse osmosis (4.0 -6.0 MPa), individually or integrally, and finally a stage of spray drying, lyophilization or evaporation.

Therefore, the need to find more efficient and sustainable solutions for the treatment of these effluents is urgent, taking into account the increasingly demanding legislation on wastewater and wastewater treatment. In all the inventions described previously, the addition of an external current is proposed.

(solvent), which implies the generation of a new residual current. On the contrary, no additional residual current is generated with the present invention, since it is the residual currents themselves generated in the mill that are mixed together.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a process for the treatment of waste from oil mills that allows to obtain by-products of industrial interest with high added value. This procedure is simple, safe and efficient, energy efficient and therefore economically, employs clean technologies considered "green", avoiding at all times the introduction of reagents in the process.

More specifically, the present invention relates to a process for treating waste from oil mills comprising a first stage of mixing solid and liquid waste, after which a liquid-solid extraction stage of compounds of interest is carried out, in that the extractant phase is water; then proceeding to a solid-liquid separation process (S / L), from which a solid phase and a liquid phase are obtained which in turn is composed of an aqueous phase highly enriched in compounds of interest (mainly polyphenolic compounds), plus an oil phase composed of residual olive oil.

The proposed procedure avoids the introduction of additional streams or reagents in the process, reusing the own by-product streams of the production process to obtain a stream rich in antioxidant compounds of high added value, as well as a stream with a minimized organic load for reuse in irrigation or discharge, devoid of the high organic load of the starting waste.

Unlike the inventions cited in the previous section, the present invention allows to carry out the treatment of waste and obtain its use without introducing any additional current in the process, but by reusing the own by-product streams of the productive process to obtain a current rich in compounds high value-added antioxidants (with a profile in synergistic heterogeneous polyphenolic compounds) and a stream with a reduced organic load for reuse in irrigation or spillage, in which a heterogeneous concentrate rich in hydroxytyrosol is obtained that has highly antioxidant properties,

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The term "comprises", which can also be interpreted as "consists of", and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and features of the invention will be derived partly from the description and partly from the practice of the

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Invention Procedure

In a first aspect, the present invention relates to a method of extracting 10 residues from oil mills, hereinafter "process of the invention" (Figure 1), which comprises the following steps: -Mixing (E1) of solid waste ( RS) and liquid waste (RL) from oil mills - Liquid-solid extraction (E2) of compounds, characterized in that the phase

The extractant comprises at least 5% water, preferably more than 15% water, more preferably between 20 and 30% water, and even more preferably about 25% water.

-Separation (E3) solid-liquid (S / L), whereby the resulting product of the previous phase is separated into a solid phase and a liquid phase.

By this procedure, after solid liquid separation a solid phase (FS) and a liquid phase (FL) are obtained which in turn is composed of an aqueous phase highly enriched in compounds of interest (mainly polyphenolic compounds), plus an oil phase Composed of residual olive oil.

In a preferred embodiment, the process of the invention comprises a stirring / homogenization step after the residue mixing stage.

We will now explain the procedure in more detail: 30 Mix of solid waste and liquid waste from oil mills (E1)

In this sense, examples of liquid residues are the olive wash water, the oil wash water, the vegetable water and the brine used in the processing of table olives. On the other hand, examples of solid residues are pomace, alpeorujo or olive bone.

The solid (RS) and liquid (RL) residues will preferably be mixed in a ratio between 1: 1 and 1:12, more preferably between 1: 1 and 1: 6, and even more preferably between 1: 1 and 1: 4. Thus, for each liter, L, of solid waste will be added to

5 the mixture between 1 and 12 L of liquid waste, preferably between 1 and 6L, more preferably between 1 and 4L.

In a particular embodiment, intended for oil mills that operate with the two-phase system, the solid waste, alpeorujo, obtained as

10 by-product of the horizontal centrifugation of olive paste, with the liquid phase obtained at the outlet of the vertical centrifuge of the oil washing process (oil washing water).

In another particular embodiment, for oil mills that operate with the three phase system,

The pomace (solid residue) is mixed with the vegetable water (liquid residue), both generated in this case in the vertical centrifugation process.

Preferably, the residues of the oil mills that are intended to be treated will be collected directly and immediately at the exit of the horizontal decanter and the vertical centrifuge,

20 respectively, during the continuous process of obtaining olive oil in the mills themselves, to avoid processes of self-fermentation of the residues that alter their composition that would act by increasing their phytotoxicity on the one hand and on the other causing the loss of compounds with high added value.

25 Optionally, the solid residue may be previously boned before being introduced into the mixing tank.

Preferably, the mixture of solid and liquid waste is stirred to achieve a homogeneous solution. For this, the mixing will preferably be carried out in

30 a mixing tank equipped with a stirrer. This agitator can be a propeller or turbine type agitator, with several propeller or turbine elements along the longitudinal axis of the agitator for a homogeneous and perfect mixture of the solid and liquid phases.

35 Liquid-solid extraction of compounds (E2)

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Oil phase and water phase separation (Figure 2, S)

In a particular embodiment, the process of the invention comprises a stage that separates an aqueous phase and an oil phase from the liquid phase obtained after solid-liquid separation.

After the S / L separation stage, the resulting liquid phase is maintained at rest so that the oil phase (FL.2) will remain in the upper part of the solid-liquid suspension due to density differences (lower oil density with respect to the aqueous phase 10), it can be easily removed and collected by means of a mechanical system for use as virgin olive oil, since it has not undergone any chemical process, and will involve between 1% and 10% w / w with respect to solid mixture - initial liquid, preferably alpeorujo or orujo mixed with oil wash water or olives.

The aqueous phase (FL.1) obtained by the process of the invention, located at the bottom, will be directed to a subsequent membrane stage for fractionation and concentration once the oil phase has been separated as described. The aqueous phase obtained will be between 65% and 75% by weight with respect to the initial weight of the mixture, solid and liquid waste.

20 If, after the S / L separation, solid residues remain dispersed in the liquid phase, they will be deposited by sedimentation in the lower part of the tank and will be incorporated into the rest of the solid phase obtained in step E3 after obtaining the aqueous phase.

At the end of the S / L separation stage, the concentration of total phenolic compounds extracted in the aqueous phase will be between 10 and 20 times greater than that of the starting liquid waste, in some cases becoming 30 times higher.

Nanofiltration

In another particular embodiment, the liquid phase obtained after the S / L separation stage, and in particular the aqueous and oily phases, preferably the aqueous phase, is fractionated and concentrated by nanofiltration, obtaining a product with a high concentration of polyphenolic compounds.

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Claims (1)

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