Physicochemical method for treating vinasse

Abstract

The present invention relates to a physicochemical method for treating vinasse, which comprises: removing suspended solids (SS) from the vinasse; recovering the aqueous phase obtained in the previous step; filtering the aqueous phase using 30 µm filters; electrolysing the filtered aqueous phase of the previous step; removing solids generated during electrolysis, by means of filters that remove solids with a size of 0.5 mm or more; removing the generated solids still suspended in the filtered liquid phase of the previous step; oxidising, with ozone, the aqueous phase of the previous step; nanofiltering the oxidised aqueous phase resulting from the previous step; and recovering the nanofiltered liquid phase, which is already suitable for discharge to bodies of water or for reuse, as it complies with environmental regulations.

Description

[0001] PHYSICAL-CHEMICAL PROCESS FOR THE TREATMENT OF VINASEED

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to the technical field of Physics and Chemistry, because it provides a physical-chemical process to treat all types of vinasse from the distillation of alcoholic beverages.

[0004] BACKGROUND OF THE INVENTION

[0005] Small and medium-sized producers in Jalisco lack access to efficient and affordable technologies for treating the vinasse waste generated by tequila production. The tequila industry in Jalisco faces the challenge of complying with the recently updated Mexican Official Standard NOM-001-SEMARNAT-2021 regarding its industrial discharges. This standard, unlike the previous version from 1996, prioritizes Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), and True Color as parameters for controlling organic pollution. Conventional treatment methods, mostly based on anaerobic, aerobic, or a combination of both biological processes, are not only inaccessible to small and medium-sized producers but are also failing to address the pollution problem caused by tequila vinasse.

[0006] Tequila vinasse is defined as a liquid residue composed of non-volatile substances that is generated and remains at the bottom of the still during the distillation of fermented agave must in the tequila production process. Fusel oil is also included, which is composed of a mixture of higher alcohol vapors (those with more than two carbon atoms, primarily amyl alcohol). Fusel oil is a clear, transparent fluid known in tequila slang as "flemasas," obtained during rectification or the second distillation (López-López & Contreras Ramos, 2015). Physically, vinasse is a reddish-brown, cloudy liquid due to its high suspended solids content, with a characteristic alcohol-caramel odor reminiscent of cooked agave (López-López & Contreras Ramos, 2015).The vinasse contains agave fibers that were not retained during the juice filtration stage, exhausted yeast cells, residual sugars, acids, esters, higher alcohols, substances that give the caramel color, etc. (López-López & Contreras Ramos, 2015; Rodríguez-Félix et al., 2018). Although these effluents are not classified as hazardous waste, they are categorized as complex wastewater whose organic load makes it one of the main pollutants that has altered the ecosystem of the Santiago-Guadalajara River (de Anda et al., 2022; Zurita et al., 2022).The lack of both financing and availability of technology are reasons why many of the tequila producing companies do not have formal wastewater treatment systems (WWTPs), with the exception of some large and medium-sized companies which have expensive facilities for the purification of vinasse through combined physicochemical and biological processes (López-López et al., 2010).

[0007] The environmental impact of vinasse

[0008] The organic load contained in vinasse, measured as Biochemical Oxygen Demand (BOD), ranges from 16,000 to 36,000 mg BOD / L, the Chemical Oxygen Demand (COD) is between 41,000 and 68,000 mg COD / L, and total solids are between 26,000 and 67,000 mg TS / L, making vinasse a highly polluting waste product (López-López & Contreras Ramos, 2015). According to the National Chamber of the Tequila Industry, 271 million liters of tequila were produced in 2017, and 527 million liters were produced in 2021 (CNIT, 2022). Considering that between 10 and 12 liters of stillage are generated for every liter of tequila produced, it is estimated that approximately 5.27 billion liters of stillage were produced in 2021. This amount has the potential to cause pollution equivalent to that generated by the raw municipal wastewater of an urban area with a population of 13.2 million inhabitants. Despite significant efforts to improve wastewater discharge standards at the national level, approximately 80% of vinasse continues to be discharged directly into water bodies (rivers, streams, lakes, reservoirs) and municipal sewer systems, or directly onto the ground without adequate treatment (López-López et al., 2010; Zurita et al., 2022). This common practice causes varying degrees of deterioration in the receiving water bodies due to the low pH, high temperature, and high organic load of these effluents. Furthermore, evidence of soil and groundwater contamination has been reported in the literature (Zurita et al., 2022). A summary of the physicochemical characteristics of the vinasse generated from the traditional Tequila production process (“100% agave”) is shown in Table 1 (López-López et al., 2010).

[0009] Following the work of López-López et al. (2010), the study by Rodríguez-Félix et al. (2018) was published, thus narrowing the knowledge gap regarding the complex composition of tequila vinasse. The work of Rodríguez-Félix et al. (2018) determined the differences in the composition of volatile organic compounds (VOCs) in tequila vinasse depending on whether the production process involves cooking the agave leaves before fermentation. This study identified more than 100 VOCs, including organic acids, esters, alcohols, aldehydes, alkanes, furan compounds, ketones, phenols, and pyrans. In this work, it was found that the volatile compound profile was similar in the vinasse obtained from processes with cooking of the agave leaves and the vinasse obtained when the leaves are not cooked prior to fermentation.However, some differences exist in the concentration of volatile compounds, suggesting that the cooking process influences the resulting composition profile of the vinasse. For example, the cooking process increases the content of furanic compounds and organic acids. Tequila vinasse obtained from an uncooked process showed a higher presence of phenolic compounds. Table 1. Physicochemical characteristics of tequila vinasse. The detailed description of the composition of vinasse aims to support the development of treatment technologies based on biological processes, since these processes, whether aerobic or anaerobic, face the challenge of decomposing VOCs classified as recalcitrant, that is, where conventional biological processes cannot degrade the organic matter.

[0010] Currently, the conventional processes for treating tequila vinasse that are most used in the industry are mentioned below (López-López et al., 2010).

[0011] 1.1. Pretreatment

[0012] The pretreatment or conditioning of vinasse consists of lowering the temperature and raising the pH from 3.5 to 6-7. The common practice for lowering the temperature from 90 to 40°C is to transport the vinasse to storage tanks or ponds under ambient conditions. pH neutralization of the vinasse is carried out in the same receiving tanks and, in some cases, in lagoons, using calcium hydroxide (Ca(OH)2). Pretreatment is a common practice in both small-scale (laboratory) and large-scale (industrial) systems (López-López et al., 2010).

[0013] 1.2. Primary treatment

[0014] 1.2.1. Sedimentation lagoons

[0015] They are very useful on an industrial scale for storage and have also been used to remove settleable solids present in vinasse (SS). However, when more than 80% of the SS is removed, the concentration of organic matter remains above 90%. Most of the lagoons used in tequila production facilities are not technically designed for this purpose, so there is a constant risk of soil and subsoil contamination (López-López et al., 2010).

[0016] 1.2.2. Dissolved air flotation

[0017] This technology has rarely been applied to the treatment of vinasse on an industrial scale, but in the cases where it has been used, a polymer has been added to accelerate the separation of suspended solids (SS) before or after biological treatment. With this method, there is a higher SS removal rate of over 80%; however, dissolved solids (DS) and biological oxygen demand (BOD) are not significantly reduced (López-López et al., 2010).

[0018] 1.3. Physical-chemical processes

[0019] This is the most widely used physicochemical process at pilot and industrial scales for treating tequila vinasse. It uses Al2(SÜ4)3 as a coagulant and a polymer as a flocculant. At an industrial scale, it is used to remove suspended solids and colloidal solids with efficiencies of 20 to 30% (López-López et al., 2010). The use of polyacrylamide as a flocculant to reduce the concentration of solids and the organic load in vinasse has also been reported (Íñiguez-Covarrubias & Peraza-Luna, 2007).

[0020] 1.4. Biological processes

[0021] 1.4.1. Anaerobic digestion

[0022] The biological process has been used for the treatment of tequila vinasse at laboratory, pilot, and industrial scales due to its technical and economic advantages over aerobic processes. An anaerobic digester is capable of removing 90 to 95% of the organic matter from tequila vinasse in the form of COD; in addition, the proposed system can produce methane-rich biogas (López-López et al., 2010; López-López & Contreras-Ramos, 2015; Moguel-Castañeda et al., 2020).

[0023] 1.4.2. Acidogenesis for hydrogen production

[0024] There is a growing interest in the production of hydrogen (H2) from organic waste through biological processes. This is primarily due to its high energy content as H2, and its use for energy production generates only water and heat as byproducts. Very few reports exist on the use of vinasse for hydrogen production, and all of these are at the laboratory level and employ a truncated version of anaerobic digestion, yielding gaseous H2 and CO2 as final products. The aforementioned studies have demonstrated significant potential for H2 production from tequila vinasse, as well as for optimizing fermentation conditions to scale up this process (López-López et al., 2010; Serrano-Meza et al., 2022).

[0025] 1.4.3. Use of microalgae

[0026] To add value to tequila vinasse, microalgae-yeast biomass was produced on vinasse diluted with tequila process water (the first rinse water from agave syrup production). In batch experiments, a vinasse concentration of 10% v / v resulted in the highest biomass productivity, pH, and microalgae growth compared to 20% and 30% v / v. The system is a promising technology for treating tequila wastewater while producing settleable materials (Barcia et al., 2020).

[0027] 1.5. Advanced Processes

[0028] Ozone is a strong oxidant widely used in drinking water purification and wastewater treatment. This oxidizing agent has been used to degrade colors, phenols, pesticides, and alcoholic vinasse as pre- and post-treatments in biological processes. In addition to ozone, oxidation with chlorine, UV radiation, and hydrogen peroxide has been reported with high color removal rates and moderate COD removal, although the latter has increased (97%) with the use of TiO2 as a photocatalyst (López-López et al., 2010). For the reduction of phenols contained in vinasse, laboratory results have been published using a coagulation-flocculation process coupled with heterogeneous photocatalysis using titanium dioxide nanoparticles (Arreóla ​​et al., 2020).

[0029] 1.6. Full-scale processes for the treatment of vinasse

[0030] López-López et al., 2010 presents a schematic summary of the most common industrial systems used to treat tequila vinasse. For reasons of industry confidentiality, the treatment systems were designated Case A, B, C, D, and E. 1.6.1. Case A

[0031] The treatment process used in each case A is the most common in micro and small distilleries for treating tequila vinasse. From a technical standpoint, Case A is considered a vinasse pretreatment or conditioning system, rather than a treatment system. The cooling and neutralization stages are achieved by lowering the temperature to below 40°C and raising the pH to > 5 using lime. This second operation is also successful in reducing suspended solids (SS); however, more than 90% of the organic matter, represented by SS and suspended solids (DS), remains unaltered and untransformed (López-López et al., 2010).

[0032] 1.6.2. Case B

[0033] This pretreatment system is frequently used in small and medium-sized distilleries for conditioning tequila vinasse. This system has the advantage that 20% of the vinasse, after pH adjustment and temperature reduction, is used in composting, primarily to provide moisture and nutrients to the soil. However, 80% of the vinasse volume is discharged into bodies of water or onto the soil, under the same conditions and disadvantages as Case A (López-López et al., 2010).

[0034] 1.6.3. Case C

[0035] This tequila stillage treatment system is regularly implemented in small and medium-sized distilleries, particularly those with sufficient physical space to construct a settling and cooling pond. This system neutralizes the pH using lime, removes suspended solids (SS), and reduces the temperature to ambient levels with a high hydraulic retention time in the pond; however, this only reduces organic matter such as BOD by 30% (López-López et al., 2010).

[0036] 1.6.4. Case D

[0037] This treatment system has recently been implemented in at least two medium-sized tequila distilleries and consists primarily of a physicochemical coagulation-flocculation process, an aerobic biological process, and an advanced ozone-based oxidation process. This treatment system achieves the complete removal of suspended solids (SS), eliminates more than 85% of organic matter such as BOD and COD, and removes color from the stillage. Although the exact cost of the treatment is unknown, the price could be considered high (López-López et al., 2010).

[0038] 1.6.5. Case E

[0039] This treatment system has been implemented in two tequila distilleries and promises to be one of the most technically feasible, though not economical, treatment systems for vinasse. The system consists of a pretreatment stage for the removal of suspended solids and pH neutralization, followed by an anaerobic biological process capable of tolerating high organic loads, and finally an aerobic process. This system achieves the removal of more than 90% of the organic matter as BOD; however, it does not reduce COD by more than 90%, and the treated effluent has a high residual color (López-López et al., 2010).

[0040] Becerra-Ospina (2014) published a study evaluating the reduction of vinasse pollutant load generated in sugarcane ethanol production through a process comprising the stages of coagulation / flocculation, sedimentation, microfiltration, and ultrafiltration using 100 and 5 kDa polyethersulfone membranes. A reduction in Chemical Oxygen Demand (COD) from 46,294 to 14,862 mg / L of O2 was achieved, along with 92% color removal and 67% total solids removal. Polyaluminum chloride (PACI) was used in the coagulation / flocculation stage, resulting in the greatest removal of pollutant load. A high fouling coefficient was observed in the microfiltration membranes, leading to a significant reduction in flow through the membrane. A reduced permeability coefficient was obtained in the ultrafiltration membranes compared to that obtained with deionized water.The amount of remaining solids in the permeate, the color, and the COD in the final effluent are the result of sugars, organic acids, minerals, and other low molecular weight compounds not removed during the evaluated treatment. As can be seen, this process would not achieve the purification standards for water recovered from vinasse, since it only separates particles of 0.45 microns, while standards NQM-001-SEMARNAT-2021 and NQM-003-SEMARNAT-1997 require that these values ​​be around 0.001 to 0.01 microns. Furthermore, it removes greater amounts of hardness, TSS, TDS, COD, and BOD, thus improving the removal of residual compounds from vinasse previously treated by other methods.

[0041] US patent document US2007051612A1 describes a process and equipment for treating residual vinasse generated in the tequila industry during the distillation and crushing stages. The purpose of this process is to remove contaminants from the vinasse and recover water using steam. The invention also relates to a heat exchanger and a vinasse evaporator used in the process to ensure that the generated steam is 100% pure water vapor. This results in water savings by reusing the steam in the process line, eliminating wastewater discharges into canals or rivers. The solids recovered from the process can be used to produce byproducts with high fiber, sugar, or protein content, or as a mixture for livestock feed, biofertilizer, or the production of ethyl alcohols.The process comprises the following stages: reception and storage of vinasse; separation of solids; heat exchange; and evaporation to recover water from the vinasse. As can be seen, this process is essentially physical, since it only consists of applying heat to evaporate the vinasse and thus recovering the water through evaporation. This is a costly process due to the large quantity of consumables required to generate the heat, and also because it requires extended periods of time to treat large volumes of vinasse.

[0042] Regarding the thesis by Retes-Pruneda, published on March 28, 2014, its objective was to propose a more efficient treatment alternative for tequila and mezcal stillage with potential for industrial application, so that discharges of this type of industrial wastewater comply with Mexican environmental regulations. Physicochemical, biological, and combined treatments were evaluated for purifying tequila and mezcal stillage. The physicochemical treatment consisted of using sodium alginate, achieving a 37% removal of total solids, 70.6% and 14.2% of BOD and COD, respectively; and 60.3% of phenols. For the biological treatment, the strains Pleurotus ostreatus 7992 and Trametes trogii 8154 were used, achieving a reduction of BOD and COD by 88% and 89.7%, respectively. and 88.9% of phenols with T. trogiiB 54 and 89.2% with P. ostreaus 7992. By applying the combination of both treatments, it was possible to remove 93% of the BODs and COD.Regarding the treatment of mezcal vinasse, alginate removed 42.4% of total solids, 18.43% of BOD, 40.7% of COD, and 56.9% of phenols. The biological treatment, using the P. ostreaus 7992 strain, removed 61.4% of BOD, 67.3% of COD, and 71.9% of phenols, while T. trogii 8154 removed 62.6% of BOD, 67.9% of COD, and 73.48% of phenols. Combining the treatments resulted in increased removal rates for BOD, COD, and phenols. As can be seen, the proposed physicochemical method is only the application of alginate, so there are no further stages where the wastewater from vinasse can be further purified or polished.

[0043] Therefore, in order to contribute to the solution of the problems found in the state of the art, a physical-chemical process has been developed for the treatment of vinasse from the distillation of alcoholic beverages, in order to comply with the regulatory requirements of water quality established in the new official standard.

[0044] The characteristic details of the present invention are clearly shown in the following description and accompanying figure, which are provided solely to illustrate the concept and some preferred embodiments thereof. Therefore, such embodiments shall not be considered as limiting the scope of protection of the present invention.

[0045] BRIEF DESCRIPTION OF THE FIGURES

[0046] Figure 1 is a block diagram of the tequila vinasse treatment process.

[0047] DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for treating vinasse, comprising the following stages: i) removing the suspended solids (SS) from the vinasse, by means of mechanical dehydration;

[0048] i) recover the aqueous phase obtained from the previous stage; iii) filter the aqueous phase using 30 pm filters, to remove total suspended solids (TSS); iv) electrolyze the filtered aqueous phase from the previous stage, so that the suspended and dissolved matter forms agglomerates of colloidal particles, for 3 to 5 min; v) remove the solids generated in the electrolysis by means of filters that remove solids of 0.5 mm or larger, which also helps in the reduction of BOD (10 to 20%); vi) remove the generated solids that have remained suspended in the filtrate of the previous stage, by dissolved air flotation (DAF), by applying a mixture of a compatible coagulant and flocculant whose proportions between them are not greater than 4:1; with these conditions a separation of total suspended solids of up to 98% is achieved; vii) oxidize the aqueous phase of the previous stage with ozone, with an ozone generator, with a minimum capacity of 1 Kg / h of ozone, outdoors, to oxidize the toxic inorganic compounds and recalcitrant organic compounds that it contains; viii) nanofilter the oxidized aqueous phase resulting from the previous stage, by primary filtration through an activated carbon and zeolite filter, and a final filtration through membranes with a pore size of 0.001 to 0.01 pm, to remove particles with sizes from 0.001 to 0.01 pm; in addition, suspended solids, color and odor are removed from the water, hardness, TSS, TDS, COD and BOD are eliminated; and ix) recover the nano-filtered liquid phase, which is already suitable for discharge into bodies of water or for reuse since it complies with the environmental regulations NOM-001 -SEMARNAT-2021 and NOM-003-SEMARNAT-1997.

[0049] One embodiment of the process for treating vinasse of the present invention is when the mechanical dehydration medium is a thyme-type dehydrator.

[0050] Another embodiment of the process according to the present invention is when electrolysis is by sedimentation and advanced flotation by dissolved air.

[0051] A preferred embodiment of the process in question, according to the present invention, is when the removal of solids in stage v) is by fine hydro-sieve filtration.

[0052] In a preferred embodiment of the process for treating vinasse, according to the present invention, the coagulant and flocculant are in a minimum amount of 20 ppm and 8 ppm, respectively, for 0.5 min, in the open air.

[0053] Another embodiment of the process in accordance with the present invention is when the nanofiltration of stage vi i) is by means of reverse osmosis.

[0054] Another modality of the process for the treatment of vinasse is when it also includes the stage of directing the removed solids to a drying bed for their subsequent disposal, in all stages where solids, sludge, particles, etc. are recovered.

[0055] EXAMPLES

[0056] The following examples are included by way of illustration to depict the concept of the invention and some preferred embodiments of the invention; therefore, these examples should not be considered as limiting the scope of protection of the present invention.

[0057] Example 1. Process for the treatment of vinasse from tequila production. The proposed vinasse treatment technology is based on a combination of advanced physicochemical processes commonly used in industrial wastewater management. This proposed process is specifically designed to remove contaminants present in tequila vinasse and thus comply with the requirements of NOM-001-SEMARNAT-2021.

[0058] The process of treating vinasse in the tequila industry was carried out in the following stages, see figure 1:

[0059] Extrusion

[0060] The process began with a primary treatment of the vinasse from tequila production, where most of the suspended solids (SS) were removed through a thyme-type dehydrator.

[0061] The suspended solids (SS) separated at this stage were subsequently sent to a drying bed for disposal; and the aqueous fraction was subjected to filtration.

[0062] Filtration

[0063] The aqueous fraction from the previous stage was subjected to filtration with a 30p filter, for the removal of the total suspended solids (TSS) contained in said aqueous fraction.

[0064] The total suspended solids (TSS) separated at this stage were also sent to a drying bed for disposal; and the resulting filtered aqueous fraction was subjected to electrolysis.

[0065] Electrolysis

[0066] The filtered aqueous fraction resulting from the previous stage was subjected to electrolysis produced by an exchange of electrons at the molecular level generated by the difference in electrical potential applied between two electrodes, for 3 to 5 min. The objective of this stage is for the suspended and dissolved matter in the filtered aqueous fraction to form agglomerates of colloidal particles, which were separated by sedimentation and advanced flotation with dissolved air, and then removed by means of fine screening.

[0067] Fine screening

[0068] The colloidal particles settled in the electrolysis were removed by means of a hydro-sieve filtration, which apart from helping to make the fine screening and remove the colloidal particles of 0.5 mm or larger, also helps in the reduction of BOD (10 to 20%) in the filtered aqueous fraction, this reduces and optimizes the subsequent treatment processes.

[0069] The separated colloidal particles were placed in a drying bed for later disposal; while the percolate obtained was subjected to clarification by dissolved air.

[0070] Clarification by dissolved air flotation

[0071] The solids that remained suspended in the percolate from the previous stage were separated using dissolved air flotation (DAF). The proposed solids separation train removed up to 98% of the total suspended solids, which were then treated in a drying bed.

[0072] Similarly, the separated total suspended solids were sent to a drying bed for later disposal; while the resulting effluent was subjected to advanced oxidation.

[0073] Advanced oxidation,

[0074] The effluent resulting from the DAF was directed to an ozone contact tower to oxidize inorganic compounds toxic to the environment and to oxidize recalcitrant organic compounds, thus facilitating their subsequent treatment. Advanced oxidation processes (AOPs) are a set of chemical treatment procedures designed to remove organic and some inorganic pollutants from wastewater through advanced oxidation via reactions with hydroxyl radicals (OH). Chemicals employing ozone (O3), hydrogen peroxide (H2O2), and / or ultraviolet light can be used for this purpose (Comninellis et al., 2008). One of these types of processes is also called in situ chemical oxidation (Huling & Pivetz, 2006). In this stage, we used ozone (O3) to carry out the oxidation, with a 4-minute contact time, at a minimum O3 concentration of 91%, at ambient temperature.

[0075] Reverse osmosis filtration.

[0076] The effluent from the advanced oxidation stage was pumped to a reverse osmosis filtration system. The purpose of this system was to polish the effluent by removing suspended solids, color, and odor. This reverse osmosis filtration (nanofiltration) retained particles ranging in size from 0.001 to 0.01 µm. This nanofiltration removed hardness, total suspended solids (TSS), total dissolved solids (TDS), chemical oxygen demand (COD), and biochemical oxygen demand (BOD), thus improving the removal of residual compounds from the effluent. Nanofiltration also removed both organic and inorganic dissolved particles, which are responsible for color, ensuring compliance with environmental regulations.

[0077] Finally, the liquid phase resulting from this stage was suitable for discharge into bodies of water or for reuse since it complied with the environmental regulations NOM-001-SEMARNAT-2021 and NOM-003-SEMARNAT-1997 respectively.

[0078] REFERENCES

[0079] Arreola, AR, Tizapa, MS, Zurita, F., Morán-Lázaro, JP, Valderrama, RC, Rodríguez-López, J. L, & Carreon-Alvarez, A. (2020). Treatment of tequila vinasse and elimination of phenol by coagulation-flocculation process coupled with heterogeneous photocatalysis using titanium dioxide nanoparticles. Environmental technology, 41 (8), 1023-1033. Retrieved from https: / / doi.Org / 10.1080 / 09593330.2018.1518994

[0080] Barcia, GEC, Cervantes, RAI, Zuniga, IT, & Van Den Hende, S. (2020). Converting tequila vinasse diluted with tequila process water into microalgae-yeast flocs and dischargeable effluent. Bioresource technology, 300, 122644. Retrieved from https: / / doi.Org / 10.1016 / j.biortech.2019.122644

[0081] Becerra, ONL (2014). Clarification of sugarcane vinasse by physicochemical treatment and membrane filtration. Undergraduate Thesis. National University of Colombia. Bogotá DC Colombia. 118 pages.

[0082] Comninellis, C., Kapalka, A., Malato, S., Parsons, S. A., Poulios, I., & Mantzavinos, D. (2008). Advanced oxidation processes for water treatment: advances and trends for R&D. Journal of Chemical Technology & Biotechnology: International Research in Process, Environmental & Clean Technology, 83(6), 769-776. Retrieved from https: / / doi.org / 10.1002 / jctb.1873 Huling, S. G., & Pivetz, B. E. (2006). In-situ chemical oxidation. Environmental Protection Agency Washington DC Office Of Water. Retrieved from https: / / apps.dtic.mil / sti / citations / ADA507297

[0083] Íñiguez-Covarrubias, G., & Peraza-Luna, F. (2007). Reduction of solids and organic load concentrations in tequila vinasses using a polyacrylamide (PAM) polymer flocculant. Revista internacional de contaminación ambiental, 23(1 ), 17-24. Retrieved from http: / / www.scielo.org.mx / scielo.php?script=sci_arttext&pid=S0188- 49992007000100002&lng=es&tlng=en.

[0084] Jáuregui-Jáuregui, JA, Méndez-Acosta, HO, González-Álvarez, V., Snell-Castro, R., Alcaraz-González, V., & Godon, JJ (2014). Anaerobic treatment of tequila vinasses under seasonal operating conditions: Start-up, normal operation and restart-up after a long stop and starvation period. Bioresource technology, 168, 33-40. Retrieved from https: / / doi.Org / 10.1016 / j.biortech.2014.04.006

[0085] López-López, A., Dávila-Vázquez, G., León-Becerril, E., Villegas-Garcia, E., & Gallardo-Valdez, J. (2010). Tequila vinasses: generation and full scale treatment processes. Reviews in Environmental Science and Bio / Technology, 9, 109-116. Retrieved from https: / / doi.org / 10.1007 / s11157-010-9204-9

[0086] López-López, A., & Contreras-Ramos, SM (2015). Effluent treatment and waste utilization. In: Science and Technology of Tequila: Advances and perspectives 2 aEdition. Effluent treatment and waste utilization pp. 343-378; ISBN: 978-607-96619-8-4 Retrieved from: https: / / ciatej.institutionalrepository.mx / jspui / handle / 1023 / 453

[0087] Luan , M. , Jing , G. , Piao , Y. , Liu , D. , & Jin , L. (2017). Treatment of Refractory Organic Pollutants in Industrial Wastewater by Wet Air Oxidation. Arabian Journal of Chemistry, 10, S769-S776. Retrieved from https: / / doi.org / 10.1016 / j.arabjc.2O12.12.003

[0088] Moguel-Chestnut , JG , Puebla , H. , Mendez-Acosta , H. 0. , & Hernandez- Martinez , E. (2020). Modeling pH and temperature effects on the anaerobic treatment of tequila vinasses. Journal of Chemical Technology & Biotechnology, 95(7), 1953-1961. Retrieved from https: / / doi.org / 10.1002 / jctb

[0089] NORSEN (2020). Multidisc screw press. Retrieved from: https: / / www. separation. com / products / multi_disc_screw_press.html?gclid=C j0KCQiA3eGfBhCeARIsACpJNU-4doAf229-FUc2Nlsy_WnKjQR- 61 sFodapWeRg11 BbkROoMT-JUplaAsbCEALw_wcB

[0090] Retes PJL (2014). Bioremediation of vinasse from the tequila and mezcal industry through physical chemical and biological treatment. Doctoral Thesis. Autonomous University of Aguascalientes. Aguascalientes, Ags., Mexico. 108 pages.

[0091] Rodríguez-Félix, E., Contreras-Ramos, SM, Dávila-Vazquez, G., Rodríguez-Campos, J., & Mahno-Marmolejo, EN (2018). Identification and quantification of volatile compounds found in vinasses from two different processes of tequila production. Energies, 11 (3), 490. Retrieved from https: / / doi.Org / 10.3390 / en11030490

[0092] Serrano-Meza, A., Garzón-Zúñiga, M. A., Moreno-Andrade, I., Barragán-Huerta, B. E., Estrada-Arriaga, E. B., Vigueras-Cortés, J. M., & Garcia-Olivares, J. G. (2022). Hydrogen and methane production from tequila vinasses in a novel hybrid reactor containing biofilm and suspended biomass. BioEnergy Research, 15(3), 1675-1690.

[0093] Stephenson, R. L, & Blackburn, J. B. (2018). The industrial wastewater systems handbook. CRC Press.

[0094] Zurita, F., Tejeda, A., Montoya, A., Carrillo, I., Sulbaran-Rangel, B., & Carreón- Álvarez, A. (2022). Generation of tequila vinasses, characterization, current disposal practices and study cases of disposal methods. Water, 14(9), 1395. Retrieved from https: / / doi.org / 10.3390 / w14091395

Claims

CLAIMS 1. A physical-chemical process for treating vinasse, characterized in that it comprises the following stages: i) removing the suspended solids (SS) from the vinasse, by means of mechanical dehydration; i) recover the aqueous phase obtained from the previous stage; iii) filter the aqueous phase using 30 pm filters, to remove total suspended solids (TSS); iv) electrolyze the filtered aqueous phase from the previous stage, so that the suspended and dissolved matter forms agglomerates of colloidal particles, for 3 to 5 min; v) remove the solids generated in the electrolysis by means of filters that remove solids of 0.5 mm or larger, which also helps to reduce BOD by 10 to 20%; vi) remove the generated solids that have remained suspended in the filtered liquid phase from the previous stage, by dissolved air flotation (DAF), by applying a mixture of a compatible coagulant and flocculant whose proportions between them are not greater than 4:1; under these conditions a separation of total suspended solids of up to 98% is achieved; vii) oxidize the aqueous phase of the previous stage with ozone, using an ozone generator with a minimum capacity of 1 Kg / h of ozone, outdoors, to oxidize the toxic inorganic compounds and recalcitrant organic compounds that it contains; viii) nanofilter the oxidized aqueous phase resulting from the previous stage, by primary filtration using an activated carbon and zeolite filter, and final filtration using membranes with a pore size of 0.001 to 0.01 pm, to remove particles with sizes from 0.001 to 0.01 pm; in addition, suspended solids, color and odor are removed from the water, hardness, TSS, TDS, COD and BOD are eliminated; and. ix) recover the nano-filtered liquid phase, which is already suitable for discharge into bodies of water or for reuse since it complies with the environmental regulations NOM-001-SEMARNAT-2021 and NOM-003-SEMARNAT-1997.

2. The process of claim 1, wherein the mechanical dehydration means is a screw-type dehydrator.

3. The process according to claim 1, wherein the electrolysis is by sedimentation and advanced flotation by dissolved air.

4. The process according to claim 1, wherein the removal of solids in stage v) is by fine hydro-sieve filtration.

5. The process according to claim 1, wherein the coagulant and flocculant are in a minimum quantity of 20 ppm and 8 ppm, respectively, for 0.5 min, in the open air.

6. The process according to claim 1, wherein the nanofiltration of step viii) is by means of reverse osmosis.

7. The process of claim 1, characterized in that it further comprises directing the removed solids to a drying bed for subsequent disposal at each stage where such solids are recovered.

Images