A treatment method for the wastewater produced in the production of fruit and vegetable beverages

Abstract

The present invention discloses a method for treating wastewater produced in the production of fruit and vegetable beverages, belonging to the field of water treatment, including: S0, removing cyanide ions in the raw water by oxidizing the cyanide ions in the raw water to form cyanide-free water; S1, the cyanide-free water is extruded by a screw extruder, and after solid-liquid separation, a by-product fruit residue and a filtrate are formed; S2, the filtrate enters an alkali neutralization container and is neutralized to a pH of 6.5 to 7.5; S4, the neutralized liquid enters an EGSB reactor for treatment to form a first treated water; S5, the first treated water enters an MEC device for treatment to form a second treated water; S6, the second treated water enters an acidification container and is acidified to a pH of 2.5 to 3.5 to form an acidified liquid; S7, the acidified liquid enters an electro-Fenton reaction for treatment to form Fenton water; S8, the Fenton water is precipitated for solid-liquid separation, and the clear liquid is discharged as up-to-standard discharged water. The present invention is specifically applicable to the treatment of wastewater generated in the production process of apple juice by apple juice production enterprises.

Description

Technical Field

[0001] The present invention relates to the field of water treatment, and particularly to a method for treating wastewater produced in the production of fruit and vegetable beverages. Background Art

[0002] Apple juice is an important type of fruit juice globally, with a significant production scale and economic value. In the future, with the upgrading of healthy consumption and technological iteration, the apple juice industry will develop towards high added value and greening of the entire industrial chain. However, during the production of apple juice, production wastewater will inevitably be formed.

[0003] Apple concentrated juice, as an important type of apple juice, has the following characteristics in the production of wastewater: a relatively high COD value, about 8000 - 12000 mg / L, pH 3.5 - 6.5; containing a large amount of pectin, sugars, and organic acids; being prone to fermentation to produce malodorous gases such as hydrogen sulfide and ammonia.

[0004] CN204897641U discloses a fruit juice wastewater treatment system that treats fruit juice wastewater by the combined method of UASB and contact oxidation. When applying this method to treat the wastewater produced during the production of apple concentrated juice, there are the following deficiencies: (1) The COD removal rate is relatively low, about 75% - 80%; (2) The problems such as hydrogen sulfide in the biogas formed during the treatment process are not solved.

[0005] CN103693809A discloses a fruit juice wastewater treatment system, which specifically mentions apple juice. This patent treats fruit juice wastewater by the combined method of anaerobic + PVA oxidation + activated sludge tank. Among them, anaerobic, PVA oxidation, and activated sludge are all biological treatments. Although the COD removal rate is relatively high, when used to treat the wastewater produced in apple juice production, there are the following deficiencies: (1) The C / N of apple production wastewater > 30, so additional urea needs to be added, and the relative amount is relatively large. (2) After anaerobic + PVA oxidation treatment, the activated sludge tank is still required for further treatment to achieve a COD removal rate of 90% in the patent, resulting in a large amount of sludge treatment and relatively complex maintenance. (3) The problems such as hydrogen sulfide in the biogas formed during the treatment process are not solved.

[0006] Therefore, fruit juice enterprises urgently need a method specifically applicable to treating the wastewater produced during the production of apple juice. Summary of the Invention

[0007] Based on the above problems, the present invention provides a method for treating wastewater produced in the production of fruit and vegetable beverages, aiming to improve at least one of the problems mentioned in the background art.

[0008] The technical solution is: a method for treating wastewater produced in the production of fruit and vegetable beverages, the fruit and vegetable beverage being apple juice, characterized by successively including the following steps:

[0009] S0. Remove the cyanide ions in the raw water by oxidizing the cyanide ions in the raw water to form cyanide-free water.

[0010] S1. The cyanide-free water is extruded by a screw extruder, and after solid-liquid separation, by-products of fruit dregs and filtrate are formed.

[0011] S2. The filtrate enters an alkali neutralization container and is neutralized to a pH of 6.5 - 7.5.

[0012] S4. The neutralized liquid enters an EGSB reactor for treatment to form the first treated water.

[0013] S5. The first treated water enters an MEC device for treatment to form the second treated water.

[0014] S6. The second treated water enters an acidification container and is acidified to a pH of 2.5 - 3.5 to form an acidified liquid.

[0015] S7. The acidified liquid enters an electro-Fenton reaction for treatment to form Fenton water.

[0016] S8. The Fenton water undergoes precipitation for solid-liquid separation, and the clear liquid is discharged as up-to-standard effluent.

[0017] The raw water is the wastewater generated in the production process of apple juice by apple juice production enterprises.

[0018] Optionally, in S0, the raw water removes the cyanide ions in the raw water through hydrogen peroxide, and the hydrogen peroxide is added in excess.

[0019] Optionally, in S1, the temperature rises by 5 - 10 °C during the extrusion of the cyanide-free water by the screw extruder.

[0020] Optionally, in S4, biogas is also by-produced after the EGSB reaction, and in S5, hydrogen is also by-produced by the MEC device.

[0021] Optionally, the device used for the EGSB reaction is an EGSB reactor. The EGSB reactor includes an EGSB reactor body and a gas-liquid separator arranged at its top. The EGSB reactor body encloses a main cavity. The gas-liquid separator is provided with an upper cavity. Inside the main cavity, a fluidized bed reaction section, a first-stage three-phase separation section, a deep purification reaction section, and a second-stage three-phase separation section are arranged in sequence from bottom to top. Inside the upper cavity, a purifier filled with packing is arranged above the liquid level. The packing is volcanic rock loaded with Thiobacillus bacteria. The gas-liquid separator is provided with an air outlet pipe and a liquid outlet pipe. The air outlet pipe is located at the top of the gas-liquid separator, and the liquid outlet pipe is located above the purifier. The bottom of the EGSB reactor body is connected with a neutralized liquid inlet pipe; the biogas is desulfurized biogas.

[0022] Optionally, S3 is also included before S4. Before the neutralized neutralization liquid enters the EGSB reactor for treatment, it first enters a pre-processor for treatment to form a pre-treated liquid. In the pre-treated liquid, pectinase and trehalose are added.

[0023] Optionally, the added amount of the pectinase is 0.05 - 3 g added to 1 L of the stock solution, and the added amount of trehalose is 0.1 - 0.3 wt% of the amount of the pectinase.

[0024] Optionally, in S5, the secondary treated water includes MEC anode effluent + 70 - 85 wt% of MEC cathode effluent, and the other 15 - 30 wt% of the MEC cathode effluent is refluxed back to the EGSB reactor.

[0025] Optionally, the raw water contains: COD 8000 - 12000 mg / L, ammonia nitrogen 70 - 100 mg / L, total sulfide 80 - 150 mg / L, total cyanide 0.6 - 1 mg / L 。

[0026] Principle of the invention and beneficial effects:

[0027] First, through the linkage of screw extrusion + EGSB reactor + MEC + electro-Fenton, when treating apple production wastewater, the COD removal rate of the present invention can reach over 91%. The added amount of urea is relatively small, and problems such as hydrogen sulfide in the biogas formed during the treatment process are solved. Subsequent maintenance is relatively easier compared to pure biochemical treatment.

[0028] The present invention also avoids the accumulation of cyanide in the environment and is more environmentally friendly. By adding pectinase and trehalose before anaerobic treatment, the COD removal rate of the finally discharged water is greatly improved. By refluxing 22% of the MEC cathode effluent, the final COD removal effect reaches 99.1%, the ammonia nitrogen removal rate reaches 94.8%, the total sulfur removal rate reaches 99.3%, and the sludge yield is only 0.12 kgDS / kgCOD. The overall effect is much better than that of the prior art. Description of the drawings

[0029] Figure 1 Schematic diagram of the process flow chart of Embodiment 1 of the present invention;

[0030] Figure 2 Schematic diagram of the structure of the EGSB reactor of the present invention;

[0031] Figure 3 Schematic diagram of the process flow chart of Embodiment 2 of the present invention;

[0032] Figure 4 Schematic diagram of the process flow chart of Embodiment 3 of the present invention;

[0033] Figure 5 Schematic diagram of the process flow chart of Embodiment 4 of the present invention;

[0034] In the figure: 1. EGSB reactor body; 2. Main cavity; 3. Gas-liquid separator; 4. Upper cavity; 5. Fluidized bed reaction section; 6. First-stage three-phase separation section; 7. Deep purification reaction section; 8. Second-stage three-phase separation section; 9. Purifier; 10. Gas outlet pipe; 11. Liquid outlet pipe; 12. Neutralizing liquid inlet pipe. Specific embodiments

[0035] The present invention will be further described below with reference to the accompanying drawings.

[0036] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "rear", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0037] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "provided with", "installed", "connected", "communicated" should be understood in a broad sense. For example, it can be fixedly connected, detachably connected, or integrally connected; it can be directly communicated, or indirectly communicated through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0038] In the present invention, the raw water refers to the wastewater generated during the production of apple juice by apple juice production enterprises.

[0039] Example 1

[0040] Please refer to Figure 1 , Figure 1 , which is a schematic process flow chart of this embodiment, Figure 2 and is the EGSB reactor of the present invention.

[0041] A water treatment method for apple juice production wastewater sequentially includes the following steps:

[0042] S1. The raw water is extruded by a screw extruder, and after solid-liquid separation, fruit residues and filtrate are formed, and the fruit residues are used for feed production.

[0043] S2. The filtrate enters an alkali neutralization container and is neutralized to about pH = 7. The purpose of neutralization is to meet the pH value requirement of the EGSB reactor.

[0044] S4. The neutralized neutralization liquid enters the EGSB reactor for treatment to form the first treated water. The structural schematic diagram of the EGSB reactor is as follows Figure 2 , which includes the EGSB reactor body 1 and the gas-liquid separator 3 arranged at its top. The EGSB reactor body 1 encloses the main cavity 2. The gas-liquid separator 3 is provided with an upper cavity 4. Inside the main cavity 2, a fluidized bed reaction section 5, a primary three-phase separation section 6, a deep purification reaction section 7, and a secondary three-phase separation section 8 are arranged in sequence from bottom to top. Above the liquid level in the upper cavity 4, a purifier 9 filled with packing is arranged. The packing is volcanic rock loaded with Thiobacillus bacteria. The gas-liquid separator 3 is provided with an air outlet pipe 10 and a liquid outlet pipe 11. The air outlet pipe 10 is located at the top of the gas-liquid separator 3, and the liquid outlet pipe 11 is located above the purifier 9. The bottom of the EGSB reactor body 1 is connected with a neutralization liquid inlet pipe 12. In fact, the EGSB reactor of the present invention is provided with a purifier 9 at the bottom of the gas-liquid separator 3 of the EGSB reactor purchased on the market (it can be set by placing a microporous plate at the bottom of the gas-liquid separator 3, loading the packing, and then placing a microporous plate on the packing).

[0045] S5. The first treated water enters the MEC device for treatment to form the second treated water.

[0046] S6. The second treated water enters the acidification container and is acidified to pH 2.5 - 3.5 to form acidified liquid.

[0047] S7. The acidified liquid enters the electro-Fenton reaction for treatment to form Fenton water.

[0048] S8. The Fenton water precipitates, and the clear liquid is discharged as the discharged water.

[0049] Among them, the purposes of EGSB, MEC, and electro-Fenton are: reducing the COD value, ammonia nitrogen, and total sulfide.

[0050] In this embodiment, through the linkage of screw extrusion + EGSB reactor + MEC + electro-Fenton, when treating apple production wastewater, the COD removal rate can reach more than 91%. Since electro-Fenton is a non-biological treatment, the supplementary amount of urea is relatively small. This embodiment also solves the problems of hydrogen sulfide in the biogas formed during the treatment process, and the subsequent maintenance of the process is relatively easy.

[0051] Example 2

[0052] Although the treatment method of Example 1 has a good COD removal effect, and compared with CN103693809A, the addition amount of urea is relatively small, and after the electro-Fenton reaction treatment, it does not need to be further treated in the activated sludge tank to achieve a good COD removal rate, and it also solves problems such as hydrogen sulfide in the biogas formed during the treatment process. However, Example 1 still has the following deficiencies: The total cyanide content in the environment after the treatment method of Example 1 increases, and cyanide is a highly toxic substance, which affects environmental safety. Through analysis, it is found that the increase in the total cyanide content is due to: In the raw material link during the juice production process, apple seeds (fruit cores) contain cyanogenic glycosides (such as amygdalin, Amygdalin), especially the cyanogenic glycoside content of bitter apple varieties is relatively high; in apple cultivation, cyanide-containing pesticides (such as some banned fumigants) are misused; in the processing link: a large number of apple seeds are mixed into the pressing process or the residue leachate is directly discharged. Since the pH of the raw water is usually between 3.5 and 6.5, even under weak acid conditions, CN ions are prone to form hydrogen cyanide, etc., resulting in cyanide overflowing into the air as long as it is not completely sealed during the entire treatment process. Therefore, although the treated effluent after the electro-Fenton reaction under the treatment method of Example 1 has a total cyanide content meeting the discharge standard, part of the cyanide overflows into the air, resulting in the accumulation of CN content in the environment and ultimately leading to safety risks.

[0053] Please refer to Figure 2 and Figure 3 , Figure 3 which is a schematic diagram of the process flow chart of this embodiment.

[0054] A water treatment method for apple juice production wastewater sequentially includes the following steps:

[0055] S0, The raw water enters the hydrogen peroxide container for treatment to form cyanide-free water. In this step, the raw water is mixed with hydrogen peroxide in the hydrogen peroxide container, aiming to remove the total cyanide in the raw water and avoid potential safety hazards. Since cyanide is more easily oxidized than high-molecular organic substances and has a better oxidation effect under acidic conditions, the cyanide content in the raw water can be removed by mixing the raw water with hydrogen peroxide to form a mixed solution.

[0056] S1, The cyanide-free water is extruded by a screw extruder, and after solid-liquid separation, fruit residues and filtrate are formed, and the fruit residues are used for feed production.

[0057] S2, The filtrate enters the alkali neutralization container to be neutralized to about pH = 7. The purpose of neutralization is to meet the pH value requirement of the EGSB reactor.

[0058] S4, The neutralized liquid enters the EGSB reactor for treatment to form the first treated water.

[0059] S5, The first treated water enters the MEC device for treatment to form the second treated water.

[0060] S6, The secondary treated water enters the acidification container and is acidified to a pH of 2.5 - 3.5 to form an acidified solution.

[0061] S7, The acidified solution enters the electro-Fenton reaction for treatment to form Fenton water.

[0062] S8, The Fenton water precipitates, and the clear liquid is discharged as the effluent water.

[0063] This embodiment utilizes the characteristic that cyanide (including hydrogen cyanide) is more easily oxidized than higher molecular organic substances, reducing the total cyanide content in the raw water to below the detection limit, and avoiding the safety risk caused by the accumulation of cyanide in the environment due to cyanide overflow.

[0064] To avoid the influence of residual hydrogen peroxide in the cyanide-free water on subsequent EGSB and MEC (which may lead to a decrease in microbial activity), a screw extruder with a temperature control system is selected. During the extrusion process, the cyanide-free water is heated by 5 - 10 °C. A 5 °C increase can increase the hydrolysis rate of hydrogen peroxide by about 2 times. After subsequent alkali neutralization, the oxygen generated by hydrolysis is discharged before entering the EGSB.

[0065] Example 3

[0066] Although Example 2 further solves the problem of the cyanide content in the environment, the COD of the effluent water can still be further reduced.

[0067] Please refer to Figure 2 and Figure 4 , Figure 4 which is the schematic diagram of the process flow of this embodiment.

[0068] A water treatment method for apple juice production wastewater sequentially includes the following steps:

[0069] S0, The raw water enters the hydrogen peroxide container for treatment to form cyanide-free water. In this step, the raw water is mixed with hydrogen peroxide in the hydrogen peroxide container, aiming to remove the total cyanide in the raw water and avoid potential safety hazards. Since cyanide is more easily oxidized than higher molecular organic substances and has a better oxidation effect under acidic conditions, the cyanide content in the raw water can be removed by mixing the raw water with hydrogen peroxide to form a mixed solution.

[0070] S1, The cyanide-free water is extruded by a screw extruder, and after solid-liquid separation, fruit residues and filtrate are formed. The fruit residues are used for feed production.

[0071] S2, The filtrate enters the alkali neutralization container and is neutralized to a pH of about 7. The purpose of neutralization is to meet the pH requirement of the EGSB reactor.

[0072] S3, The neutralized solution enters the pre-processor for treatment to form a pre-treated solution. In this step, pectinase is mixed into the neutralized solution in the pre-processor, and the mixing method can be by dropping.

[0073] S4, The pretreatment liquid enters the EGSB reactor for treatment to form the first treated water.

[0074] S5, The first treated water enters the MEC device for treatment to form the second treated water.

[0075] S6, The second treated water enters the acidification container and is acidified to pH 2.5 - 3.5 to form the acidified liquid.

[0076] S7, The acidified liquid enters the electro - Fenton reaction for treatment to form Fenton water.

[0077] S8, The Fenton water precipitates, and the clear liquid is discharged as the discharged water.

[0078] In this embodiment, aiming at the problem that the decomposition rate of pectin in the raw water is slow under anaerobic conditions, which affects the indicators such as COD of the final discharged water, by adding pectinase to the neutralization liquid, the decomposition rate under anaerobic conditions is increased, thereby further reducing the indicators such as COD of the final discharged water.

[0079] In order to ensure that the activity of pectinase is not affected under anaerobic conditions, when adding pectinase, trehalose can be added simultaneously.

[0080] In Examples 1 - 3, the second treated water is formed by mixing the MEC cathode effluent with the MEC cathode effluent. Among them, the hydrogen in the MEC cathode water has been removed before mixing, and this hydrogen is used in combination with the hydrogen generated in the MEC and the enterprise steam boiler. The biogas after treatment in the EGSB reactor is used in combination with the micro - gas turbine in the enterprise.

[0081] Example 4

[0082] Although Example 3 further reduces the COD, the COD of the discharged water can still be further reduced.

[0083] Please refer to Figure 2 and Figure 5 , Figure 5 which is the schematic diagram of the process flow chart of this embodiment.

[0084] A water treatment method for apple juice production wastewater sequentially includes the following steps:

[0085] S0, The raw water enters the hydrogen peroxide container for treatment to form cyanide - free water. In this step, the raw water is mixed with hydrogen peroxide in the hydrogen peroxide container. The purpose is to remove the total cyanide in the raw water to avoid potential safety hazards. Since cyanide is more easily oxidized than high - molecular organic matter and has a better oxidation effect under acidic conditions, the cyanide content in the raw water can be removed by mixing the raw water with hydrogen peroxide to form a mixed liquid.

[0086] S1. The cyanide-free water is extruded by a screw extruder, and after solid-liquid separation, fruit residues and filtrate are formed, where the fruit residues are used for feed production.

[0087] S2. The filtrate enters an alkali neutralization container and is neutralized to about pH = 7. The purpose of neutralization is to meet the pH requirement of the EGSB reactor.

[0088] S3. The neutralized liquid enters a preprocessor for treatment to form a pretreated liquid. In this step, pectinase is mixed into the neutralized liquid in the preprocessor, and the mixing method can be by dropping.

[0089] S4. The pretreated liquid enters an EGSB reactor for treatment to form the first treated water.

[0090] S5. The first treated water enters an MEC device for treatment to form the second treated water. The second treated water includes MEC anode effluent + 70 - 85 wt% MEC cathode effluent, and the other 15 - 30 wt% MEC cathode effluent is recycled back to the EGSB reactor.

[0091] S6. The second treated water enters an acidification container and is acidified to pH 2.5 - 3.5 to form an acidified liquid.

[0092] S7. The acidified liquid enters an electro-Fenton reaction for treatment to form Fenton water.

[0093] S8. The Fenton water precipitates, and the clear liquid is discharged as the discharged water.

[0094] In this embodiment, by recycling 15 - 30 wt% of the MEC cathode effluent back to the EGSB reactor, indicators such as COD are further reduced.

[0095] Example 5

[0096] The treatment methods of Example 2, Example 3 and Example 4 are respectively investigated. During the investigation, the raw water sources of the three are from the same source, with the same composition and content. When Example 2 is implemented, the pretreatment is closed and there is no reflux of the MEC cathode effluent; when Example 3 is implemented, the pretreatment is turned on and there is no reflux of the MEC cathode effluent; when Example 4 is implemented, the pretreatment is turned on, and in addition to the reflux of 22 wt% of the MEC cathode effluent, the other conditions are the same. In the pretreatment, the addition amount of pectinase is 0.1 g / L (that is, for 1 L of raw water, 0.1 g of pectinase is added), and the addition amount of trehalose is 0.15 wt% of the amount of pectinase. The raw water for investigation: COD 9500 mg / L, ammonia nitrogen 82 mg / L, total sulfide 120 mg / L, total cyanide 0.98 mg / L.

[0097] The investigation results are as follows:

[0098] ⑴ Detection of total cyanide content in cyanide-free water: No total cyanide was detected in the cyanide-free water of Examples 2 to 4, indicating that the cyanide-free water will not enter the environment during the subsequent process and the hydrogen peroxide container reaches the treatment target after treatment.

[0099] ⑵ The sludge yield is as shown in Table 1 below:

[0100] Table 1 Sludge Yield

[0101] From the comparison between Example 2 and Example 3, the pretreatment did not increase the total sludge yield. From the comparison between Example 3 and Example 4, the reflux of 22 wt% of the MEC cathode effluent reduced the sludge yield.

[0102] ⑶ The test results of the discharged water are as shown in Table 2 below.

[0103] Table 2 Discharged Water

[0104]

[0105] As can be seen from Table 2, the reflux of 22 wt% of the MEC cathode effluent has good effects on the removal of COD, ammonia nitrogen and total sulfur. The addition of pectinase and trehalose greatly improves the COD removal rate. The water treatment method of Example 4 has a COD removal rate of 99.1%, an ammonia nitrogen removal rate of 94.8%, and a total sulfur removal rate of 99.3% for the raw water. The sludge yield is only 0.12 kgDS / kgCOD. The overall effect is far better than that of the prior art, and it does not increase the cyanide accumulation in the environment, avoiding safety risks.

[0106] In the present invention, unless otherwise specified, they are all prior arts.

[0107] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A treatment method for the production wastewater of fruit and vegetable beverages, where the fruit and vegetable beverage is apple juice, characterized in that, sequentially including the following steps: S0, removing the cyanide ions in the raw water by oxidizing the cyanide ions in the raw water to form cyanide-free water; S1, the cyanide-free water is extruded by a screw extruder, and after solid-liquid separation, by-products fruit dregs and filtrate are formed; S2, the filtrate enters an alkali neutralization container and is neutralized to pH 6.5 - 7.5; S4, the neutralized neutralization liquid enters an EGSB reactor for treatment to form first treated water; S5, the first treated water enters an MEC device for treatment to form second treated water; S6, the second treated water enters an acidification container and is acidified to pH 2.5 - 3.5 to form an acidified liquid; S7, the acidified liquid enters an electro-Fenton reaction for treatment to form Fenton water; S8, the Fenton water is precipitated for solid-liquid separation, and the clear liquid is discharged as up-to-standard discharge water; The raw water is the wastewater generated in the production process of apple juice by apple juice production enterprises.

2. The treatment method of the wastewater produced in the production of fruit and vegetable beverages according to claim 1, characterized in that, In S0, the cyanide ions in the raw water are removed by hydrogen peroxide, and the hydrogen peroxide is added in excess.

3. The treatment method of the wastewater produced in the production of fruit and vegetable beverages according to claim 1, characterized in that, In S1, the temperature rises by 5 - 10 °C during the extrusion of the cyanide-free water by the screw extruder.

4. The treatment method of the wastewater produced in the production of fruit and vegetable beverages according to claim 1, wherein, In S4, biogas is also by-produced after the EGSB reaction. In S5, hydrogen is also by-produced by the MEC device.

5. The treatment method of fruit and vegetable beverage production wastewater according to claim 4, characterized in that, The device used for the EGSB reaction is an EGSB reactor. The EGSB reactor includes an EGSB reactor body (1) and a gas-liquid separator (3) arranged at its top. The EGSB reactor body (1) encloses a main cavity (2). The gas-liquid separator (3) is provided with an upper cavity (4). In the main cavity (2), a fluidized bed reaction section (5), a first-stage three-phase separation section (6), a deep purification reaction section (7), and a second-stage three-phase separation section (8) are arranged in sequence from bottom to top. Above the liquid level in the upper cavity (4), a purifier (9) filled with packing is arranged. The packing is volcanic rock loaded with Thiobacillus bacteria. An air outlet pipe (10) and a liquid outlet pipe (11) are arranged on the gas-liquid separator (3). The air outlet pipe (10) is located at the top of the gas-liquid separator (3), and the liquid outlet pipe (11) is located above the purifier (9). The bottom of the EGSB reactor body (1) is connected with a neutralization liquid inlet pipe (12); the biogas is desulfurized biogas.

6. The treatment method of the wastewater produced in the production of fruit and vegetable beverages according to claim 1, wherein After S2 and before S4, S3 is also included. Before the neutralized neutralization liquid enters the EGSB reactor for treatment, it first enters a pre-processor for treatment to form a pre-treated liquid. In the pre-treated liquid, pectinase and trehalose are added.

7. The treatment method of the fruit and vegetable beverage production wastewater according to claim 6, characterized in that, The added amount of the pectinase is 0.05 - 3 g added to 1 L of the original liquid, and the added amount of trehalose is 0.1 - 0.3 wt% of the amount of pectinase.

8. The treatment method of the fruit and vegetable beverage production wastewater according to claim 6, characterized in that, In S5, the second treated water includes MEC anode effluent + 70 - 85 wt% of MEC cathode effluent, and the other 15 - 30 wt% of MEC cathode effluent is refluxed back to the EGSB reactor.

9. The treatment method of the fruit and vegetable beverage production wastewater according to any one of claims 1 to 8, characterized in that The raw water contains: COD 8000 - 12000 mg / L, ammonia nitrogen 70 - 100 mg / L, total sulfide 80 - 150 mg / L, total cyanide 0.6 - 1 mg / L.

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