DE102016008048A1 - Process for the recycling and reuse of liquid waste oils from olive oil extraction - Google Patents

Abstract

This invention relates to a process for recycling and reusing liquid waste liquids from olive oil extraction, the process comprising the steps of: passing the waste water from the wash or the vegetable water through a filtration system consisting of at least one filter and the separation apparatus is downstream; Introducing the recycled water into an equalization tank of drinking water upstream of the separation apparatus for the olive oil extraction process; and reintroducing the water mixture into the phase separation plant. The method of this invention is aimed at reducing drinking water consumption, recycling the wastewater and, on the other hand, avoiding some compounds such as the phenolic compounds from being wasted in these problem waters.

Description

Field of the invention

This invention relates to the production of olive oil, in particular to the phase of olive oil extraction.

Background of the invention

Olive oil is a food product that is rich in vitamins and antioxidants and is used as a seasoning because it gives the food a special taste and aroma. It is made from olives, the fruit of the olive tree. It is a classic food in contemporary cuisine, which is widely used in the Mediterranean diet. Generally, it is available in most kitchens. Olive oil also has health benefits because it helps to reduce the risk of heart attack and diabetes, it is digestive and prevents the formation of stones and also some cancers. The quality of the oil is determined by the region, the variety and the maturity of the olives, the nature of the products (they influence the acidity of the olive oil), the extraction process, the type of preservation and the age of the olive oil.

Olive oil production involves a number of steps, from the harvesting of the olives to the storage of the olive oil, including a series of transformations, which enables its production and ensures its quality. The traditional methods of olive processing are now replaced by modern extraction methods.

Currently, the extraction of virgin olive oil produces various types of waste: solid, liquid and semi-liquid waste.

In the continuous three-phase centrifugation system, an oily phase (20%), a solid residue (30%) and an aqueous phase (50%) are obtained. This aqueous phase, together with the waters from the washing of the olives and those resulting from the processing, is commonly referred to as "mill oil wastewater" and contains soft tissue from the olive meat and a very stable oily emulsion ( Borja et al. 1995 ). This extraction process yields about 1.25 l of oil mill wastewater per kg of processed olives.

If the extraction of the virgin olive oil is carried out by means of a continuous two-phase centrifugation system (which is the more ecological and also more frequently used system), then the amount of effluent produced is 0.25 l per kg of processed olives ( Borja et al., 2006 ). This extraction system produces the following residues: water from the washing of olives, water from washing and the cleaning of olive oil, and also a sludge known as olive pomace ( Raposo et al., 2003 ).

The water resulting from the washing of the olive oil contains large concentrations of organic matter, mainly due to its content of phenolic compounds, which depends on the cultivar and the degree of ripeness and on the volume of water used for the washing ( Borja et al., 2006 ).

In the olive oil extraction process, whether it is by a two-phase system, a three-phase system or the traditional system with a press, not only significant amounts of drinking water used in the so-called oil washing are wasted, but also the vegetable water resulting from the process of Olive oil extraction itself comes from. At the same time, the resulting waste water entrains some compounds of great commercial interest in the valorisation of olive oil, such as the phenolic compounds. These compounds have antioxidant, anti-inflammatory and anticoagulant effects that are of great benefit to the health.

Thus, by means of a recycling process and the use of filtration systems, the present invention aims at forcing the vegetable water or wash water after filtration to re-enter the olive oil scrubbing process or the horizontal decanter or even another phase as recycled water. the reintroduction of the recycled water proved to be beneficial. Each of these water can be recycled independently or simultaneously.

With respect to the extraction phase, none of the currently existing solutions reuse the plant water and / or wash water and reintroduce it into the process so as to conserve the drinking water and not to waste the phenolic compounds.

Table I shows the variation range of the physical and chemical composition of the water produced during the washing of the olive and olive oil purification as obtained in a sample of 6 mills located in Spain in the provinces of Cordoba and Jaen (adapted from Borja et al., 2006 ).

The results presented in Table I allow us to conclude that these waste liquids can not be discharged into the natural aquatic environment without any treatment, especially due to their organic load. The BOD ₅ and COD values of these waters are above the legal disposal limits for the natural water environment.

Its use as irrigation water also has some limitations, as some of the phenolic compounds have phytotoxic properties. The conventionally used solution was its storage in large evaporation basins. However, the use of these basins has several disadvantages, such as limited capacity and the outflow of odor, because fermentation processes easily occur.

On the other hand, the important biological properties of the phenolic compounds present increase the need for them to be obtained by the valorisation of the olive oil and / or other uses.

The existing literature describes a number of biological, aerobic and anaerobic processes for treating these waters ( Ammary, 2005 ; Borja et al., 2006 ), namely advanced oxidation processes, such as ozonation, the addition of Fenton's reagent, electrochemical oxidation ( Marques, 2001 ) or various combinations thereof ( Khoufi et al., 2006 ). In addition, however, in that they are generally quite expensive because their goal is the degradation of organic material, they inevitably lead to the loss of phenolic compounds.

The use of filtration processes, including membrane filtration processes, enables recovery of the phenolic compounds contained therein, in addition to solving the environmental problem caused by these waters. Membrane processes are well suited for this valorization because they do not require large areas, are nondestructive and involve lower energy consumption compared to other processes, such as biological processes ( Madimu et al., 2012 ). In addition, the membranes are very versatile, which makes it possible to different components of a solution based on differences in size, as occurs in the microfiltration, ultrafiltration and also in part in the nanofiltration, or due to differences that affect other features which affect permeability, such as solubility and diffusivity (reverse osmosis) or state of aggregation (membrane distillation or osmotic distillation) Mulder, 1996 ]).

According to the published and summarized above documentation, and based on contacts established with olive oil extraction producers, it has been found that none of the systems used uses filtration technologies with the aim of reusing wastewater in the process of olive oil extraction as recycled water following treatment. either with the aim of reducing or eliminating the consumption of drinking water, or even increasing the concentration of the phenolic compound in the native olive oil.

In addition to this finding, while researching solutions using membrane filtration or other filtration technology for this purpose, we could not find any other type of technology that uses horizontal or vertical centrifuge or any other step of the process in which drinking water is used will be arranged to recycle the wastewater and reintroduce it back into the process, especially in vertical centrifuges for olive oil washing.

Brief description of the figures

The 1 and 2 refer to schematic representations for the specific case of the vertical centrifuge in the context of the current or the new method.

1 Represents the washing process carried out in the vertical centrifuge (currently);

• – Filtern der Abfallflüssigkeit, wodurch die Abwässer zu recycelten Wassern umgewandelt werden;
• – Erhöhen der Konzentration an phenolischen Verbindungen in dem endgültigen Olivenöl.

2 Figure 4 illustrates the positioning of the filtration system of this invention in the olive oil extraction process and in the specific case of the vertical centrifuge. It will be appreciated that the invention follows the present extraction process, thereby simultaneously performing two operations:

• - filtering the waste liquid, which converts the waste water into recycled water;
• - Increase the concentration of phenolic compounds in the final olive oil.

3 Figure 3 illustrates the positioning of the filtration system of this invention in the olive oil extraction process with a horizontal three-phase centrifuge.

It should be noted that the waste liquid used in the 2 and 3 is shown due to the lower volume of wastewater has a high concentration of solids.

The olive oil that lives in the 2 and 3 mentions impurities and is currently undergoing final filtration with diatomaceous earth at a later stage.

The filters may also include cartridges, microfiltration, ultrafiltration, nanofiltration, reverse osmosis and others.

Summary of the invention

• – einfache Maschenfilter, Faserfilter oder Mikrofiltration, Ultrafiltration, Nanofiltration oder Umkehrosmose, mit keramischen oder polymeren Membranen, oder Membranverfahren im Allgemeinen;
• – Abfolgen von den zuvor genannten Filtern oder von anderen Filtriertechnologien, wobei irgendwelche Kombinationen oder Wiederholungen zulässig sind.

The present invention consists of at least one filtration system which may be a single or a series of filtration systems arranged in series or in parallel, the filtration technologies downstream of the separation apparatus being those listed below:

• Simple mesh filters, fiber filters or microfiltration, ultrafiltration, nanofiltration or reverse osmosis, with ceramic or polymeric membranes, or membrane processes in general;
• - Sequences of the aforementioned filters or other filtration technologies, with any combinations or repetitions being permitted.

Once the sequence of filtration technologies has been selected that is most appropriate for the process to be performed, it will be used as follows:
One option: the wastewater filtration technologies are placed at the exit of the vertical centrifuge associated with the 2- or 3-phase process, or, in the case of extraction presses, they may also be at the outlet of the decanter, said filtered wastewater being recycled by means of recirculation the olive oil scrubbing process, if necessary with the addition of drinking water for balancing purposes, upstream of the vertical centrifuge or the horizontal centrifuges.

In this way, the intake of new water is reduced and at the same time the sewage flow is reduced, and it is also the loss of valuable compounds, as is the case for phenolic compounds prevented.

Another option is to place the filtration system at the outlet of the horizontal 3-phase centrifuge, where the vegetable water is filtered and passed on for use as olive oil wash water or in the horizontal or vertical separating decanters.

The two options described above can be used independently or simultaneously.

The effluents are forced in this way to circulate in a closed circuit, whereby they are transported by means of pumps.

When fully recycled and ready to re-enter, for example into a vertical centrifuge, they can be previously balanced in a surge tank with potable water to compensate for the loss of liquid in the residues retained in the various filtration stages. The method of the present invention has added value to nutrition due to the fact that in the final product, i. H. the olive oil produced by this process retains the phenolic compounds and other beneficial compounds which have and promote nutritional value and consequently an impact on the health of consumers.

The method of the present invention is aimed at reducing drinking water consumption, recycling wastewater and, on the other hand, avoiding that compounds that would be wasted in such problem waters now act as a barrier to migration of the same compounds from that olive oil, due to the difference in the concentration of phenolic compounds between the recycled waters and olive oil.

Detailed description of the invention

• – Verringerung der Menge an Trinkwasser, das pro kg verarbeiteter Oliven verbraucht wird;
• – Verringerung des Abwasservolumens pro kg verarbeiteter Oliven, das aus dem Olivenölwaschverfahren herrührt;
• – Verringerung des Gehalts an phenolischen Verbindungen in den Abwässern, wodurch deren phytotoxische Wirkungen verringert werden;
• – Erhöhung des Gehalts an phenolischen Verbindungen in dem Olivenöl nach dem Extraktionsverfahren, wodurch der Wert des Olivenöls, das aus der Mühle erhalten wird, gesteigert wird.

The present invention solves the following problems in the process of producing olive oil, especially in the extraction phase, as opposed to all present extraction processes, all of which share the following problems:

• - reducing the amount of drinking water consumed per kg of processed olives;
• - reducing the volume of waste water per kilogram of processed olives resulting from the olive oil washing process;
• - reducing the content of phenolic compounds in the effluents, thereby reducing their phytotoxic effects;
• - increasing the content of phenolic compounds in the olive oil after the extraction process, thereby increasing the value of the olive oil obtained from the mill.

In addition, and in particular as regards the available technology, the present invention also improves the following aspects for each of them:
Two Phase Extraction Process: The solid waste retained in the filtration system (s) represents an economic value for operations that recover the oil that is still present in these materials or for other valorization processes in which higher organic concentration is beneficial :
Three-Phase Extraction Process: The solid waste trapped in the filters represents an economic value for plants that recover the oil that is still present in these materials. Second, considering that in this process, water consumption is currently above that of the two-phase process, one could reverse the trend towards the two-phase system and maintain the three-phase system because it offers a higher yield in olive oil extraction, but on the other hand higher costs in terms of water consumption and also the larger volume of wastewater.

• – nicht nur die erforderliche Menge an Wasser verringert wird;
• – das Abwasser aus dem Verfahren verringert wird;
• – sondern auch der Verlust an Elementen mit einem Mehrwert für das Endprodukt verringert wird, nämlich die phenolischen Verbindungen.

The present invention consists essentially of using at least one filtration system in a sequence arranged in series or in parallel, or separate, collecting the effluent from the three-phase or two-phase centrifuge, vertical centrifuge, gravity decanters, or another method using drinking water and, after filtration of these waters, introducing these waters into the vertical centrifuge or into another phase of the olive oil extraction process as recycled water such that:

• - not only the required amount of water is reduced;
• - the effluent from the process is reduced;
• - But also the loss of elements with added value for the final product is reduced, namely the phenolic compounds.

This principle of using at least one filtration system downstream of the filtration apparatus may also be associated with any phase of the process using drinking water.

This innovation, in addition to the aspects highlighted above, avoids the deposition of large volumes of wastewater with high organic loads into aeration basins, along with the harmful consequences of this approach.

The filtration devices that can be used are filters with fibers, meshes, ceramic or polymeric membranes or in the field of microfiltration, ultrafiltration or nanofiltration, reverse osmosis or other filtration techniques. These filtration techniques are adapted in their number, sequence and characteristics to the flow of the installation to be treated, but also to the characteristics of each cultivar to be filtered and the method used.

The circulation of the waste liquids to be treated takes place in a closed circuit and they are continuously recirculated from the outlet of the effluents until their re-entry as wash water into the apparatus, namely the vertical centrifuge. Before the water re-enters the apparatus with which the filtration is associated, it can be mixed / balanced with potable water to maintain the correct flow rate.

The drinking water, after being used in the extraction process, becomes wastewater. Therefore, thanks to recycling, less drinking water is used. This reduction requires further back in the process a lower wastewater volume, which is directly proportional to the smaller amount of drinking water used.

The phytotoxic effect is also reduced because the organic burden that was once released in large quantities into the surrounding environment is now retained in the filters (which can be recycled by specialized farms) or in the olive oil, thereby adding value to this product becomes.

Subject of the invention

• a) Passieren des pflanzlichen Wassers oder Abwassers aus der Olivenölwaschung durch ein Filtrationssystem, das aus mindestens einem Filter besteht und der Trennapparatur nachgeschaltet ist;
• b) Erneutes Einführen der Wassermischung in die Phasentrennanalage.

The present invention relates to a process for the recycling and reuse of liquid effluents from olive oil extraction, characterized in that it comprises the following steps:

• a) passing the vegetable water or wastewater from the olive oil washing through a filtration system, which consists of at least one filter and the separation apparatus is connected downstream;
• b) Re-introducing the water mixture into the phase separation system.

In a preferred embodiment, the recycled water from step b) is previously circulated through a surge tank with drinking water upstream of the separation apparatus of the oil extraction process and only then introduced into the separation apparatus.

Preferably, the filter used is selected from simple mesh filters, fiber filters, micro, ultra or nanofiltration, reverse osmosis, with ceramic or polymeric membranes, and membrane processes in general.

In a preferred embodiment, the filtration system is the membrane process.

In a convenient embodiment, which can be combined with any of the foregoing, the method includes a step prior to filtering, wherein step a) is preceded by passing the vegetable water or wastewater from washing through a simple mesh filter. This step is suitable for removing larger elements that block or reduce the efficiency of the filtration system downstream of the separation apparatus.

Preferably, the separation apparatus is selected from horizontal and vertical centrifuges.

Conveniently, the filters of the at least one filtration system are arranged in series.

Preferably, the filters of the at least one filtration system are arranged in parallel.

It will be apparent to those skilled in the art that numerous minor changes are possible, but are within the scope of the present invention.

The present invention is limited only by the scope of the following claims.

source

• Ammary B. (2005). Treatment of olive mill wastewater using an anaerobic sequencing batch reactor. Desalination, 177, 157-165 ,
• Borja R., Martín A., Alonso V., Garcia I., Banks CJ (1995). Influence of different aerobic pre-treatments on the kinetics of anaerobic digestion of olive mill wastewater. Water Research, 29 (2) 489-495 ,
• Borja R., Raposo F., Rincon B. (2006). Treatment technologies of liquid and solid wastes from two-phase olive oil mills. Grasas & Aceites, 57 (1) Enero-Marzo, 32-46 ,
• Khoufi S., Aloui F, Sayadi S. (2006). Treatment of olive oil mill wastewater by combined process electro-Fenton reaction and anaerobic digestion (10) 40, 2007-2016 ,
• Marques IP (2001). Anaerobic digestion treatment of olive mill wastewater for effluent re-use in irrigation. Desalination, (137) 233-239 ,
• Mudimu OA, Peters M., Brauner F., Braun G. (2012). Overview of membrane processes for the recovery of polyphenols from olive mill wastewater. At the. J. Environ. Sci. 8, 195-2012 ,
• Mulder M. (1996). "Basic Principles of Membrane Technology", 2nd ed. Kluwer Academic Publishers, Netherlands ,
• Raposo, F., Borja, R., Sánchez, E., Martín, MA, Martín A. (2003). Inhibition kinetics of overall substrate and phenolics removal during the anaerobic digestion of two-phase olive mill effluents (TPOME) in suspended and immobilized cell reactors. Process Biochem, 39, 425-435 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• Borja et al. 1995 [0005]
• Borja et al., 2006 [0006]
• Raposo et al., 2003 [0006]
• Borja et al., 2006 [0007]
• Borja et al., 2006 [0011]
• Ammary, 2005 [0015]
• Borja et al., 2006 [0015]
• Marques, 2001 [0015]
• Khoufi et al., 2006 [0015]
• Madimu et al., 2012 [0016]
• Mulder, 1996 [0016]

Claims (8)

Process for the recycling and reuse of liquid waste liquids from olive oil extraction, characterized in that it comprises the following steps: a) passing the vegetable water or waste water from the washing through a filtration system consisting of at least one filter and downstream of the separation apparatus, resulting in recycled water; b) Re-introducing the recycled water into the phase separation apparatus. Process for the recycling and reuse of liquid waste liquids from olive oil extraction according to claim 1, characterized in that the recycled water from step b) of claim 1 is previously circulated through a surge tank with drinking water upstream of the separation apparatus of the oil extraction process, and only then introduced into the separation apparatus. A method of recycling and reusing liquid waste oils from olive oil extraction according to claim 1, characterized in that the filter consists of fiber filters, micro, ultra or nanofiltration, reverse osmosis, with ceramic or polymeric membranes, and membrane processes in general. Process for the recycling and reuse of liquid waste oils from olive oil extraction according to one of the preceding claims, characterized in that the filtration system is the membrane process. Process for the recycling and reuse of liquid waste liquids from olive oil extraction according to claim 1, characterized in that the separation apparatus is selected from a vertical and horizontal centrifuge. Process for the recycling and reuse of liquid waste oils from olive oil extraction according to claim 1, characterized in that the filters of at least one filtration system are arranged in series. Process for the recycling and reuse of liquid waste liquids from olive oil extraction according to claim 1, characterized in that the filters of at least one filtration system are arranged in parallel. Method according to one of the preceding claims, characterized in that the step a) precedes a passage of the vegetable water or waste water from the washing through a simple mesh filter.

Images