A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load

Abstract

The application relates to the technical field of water treatment, and specifically discloses a treatment method for mixed industrial wastewater containing complex chromium, sulfides and high organic load, which comprises the following steps: adding anaerobic bacteria agents, hydrolytic acidification enhancers and micro-electrolysis fillers into the wastewater to be treated, stirring, and introducing CO2 into the reaction system; wherein the micro-electrolysis filler is prepared by spraying a modified polyaniline film with silicon dioxide on the surface of porous pretreated ceramsite loaded with nano-iron through atomic layer deposition treatment, and the porous pretreated ceramsite is obtained by high-temperature melting, extrusion and then water cooling of polyester raw materials; the anaerobic bacteria agents comprise anaerobic mixed bacteria additives and enhanced bacteria additives; and the hydrolytic acidification enhancers mainly comprise humic acid ammonium salt, pectin and sucrose. The application has the characteristics of improving the removal rate of complex chromium in the mixed industrial wastewater containing complex chromium, sulfides and high organic load, reducing the total chromium emission concentration, and simultaneously reducing the COD and sulfide concentrations of the wastewater.

Description

Technical Field

[0001] This application relates to the field of water treatment technology, and more specifically, it relates to a method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load. Background Technology

[0002] With the rapid development of industry, the treatment of various industrial wastewater problems has become increasingly prominent. The treatment of complex mixed industrial wastewater containing complexed heavy metals, high concentrations of recalcitrant organic matter, and sulfides is one of the important challenges facing industrial wastewater treatment today.

[0003] The main treatment problems and technical challenges for this type of complex mixed wastewater are as follows: 1. High chromium content, mainly Cr(III) complex chromium ions, which are highly stable and toxic, making them difficult to remove; 2. High organic matter concentration, mainly including polycyclic aromatic hydrocarbons such as phenol and phenolic resins, some of which are difficult to biodegrade, resulting in severe impacts from high concentrations in the influent to the biological treatment system and unstable system operation; 3. High sulfur content, mainly sulfides such as H2S and hydrogen sulfide produced by sulfate reduction, which have a strong inhibitory effect on the subsequent biological treatment system; 4. Lack of effective and sustainable deep treatment technologies, resulting in unsatisfactory overall treatment effect of the mixed wastewater.

[0004] Currently, common technologies and methods for treating mixed industrial wastewater include advanced chemical oxidation, traditional biological treatment, and adsorption. However, these methods or technologies have significant limitations in treating complex mixed industrial wastewater containing chromium, high COD, and sulfides, with problems such as low chromium removal rate, severe system inhibition, and poor deep treatment effect. Summary of the Invention

[0005] In order to improve the removal rate of complexed chromium, sulfides and high organic load in mixed industrial wastewater, reduce the total chromium emission concentration, and reduce the COD and sulfide concentration of the wastewater, this application provides a method for treating mixed industrial wastewater containing complexed chromium, sulfides and high organic load.

[0006] The present application provides a method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load, using the following technical solution:

[0007] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load includes the following steps:

[0008] Anaerobic bacteria, hydrolysis acidification enhancer, and micro-electrolysis packing were added to the wastewater to be treated. The mixture was stirred, and CO2 was introduced into the reaction system. After running for 5-10 days, the dissolved oxygen (DO) was controlled to be 0.3±0.1 mg / L by adding oxygen.

[0009] Among them, the micro-electrolysis filler is made by loading nano-iron onto the surface of porous pretreated ceramsite through atomic layer deposition and then spraying it with a silica-modified polyaniline film. The porous pretreated ceramsite is obtained by melting and extruding polyester raw materials at high temperature and then water-cooling to create pores. The anaerobic bacteria agent includes anaerobic mixed bacteria additives and enhanced bacteria additives. The anaerobic mixed bacteria additives mainly include sulfate-reducing bacteria and acetic acid-producing bacteria, while the enhanced bacteria additives mainly include alkali-producing bacteria and acid-producing bacteria.

[0010] Hydrolysis acidification fortifiers mainly include humic acid ammonium salts, pectin, and sucrose.

[0011] By adopting the above technical solution, this application uses surface-modified micro-electrolysis packing material, and utilizes the hydrolytic acid production effect of highly efficient anaerobic bacteria, combined with strictly controlled micro-aerobic conditions (DO<0.5mg / L), to efficiently remove complexed chromium, as well as recalcitrant organic matter and sulfides from wastewater from a synergistic physicochemical and biological perspective. At the same time, by adjusting the pH of the reaction system and using the co-catalytic effect of hydrolysis acidification enhancer, the wastewater to be treated is transformed and removed more efficiently and completely, achieving rapid removal and deep treatment of mixed industrial wastewater containing complexed chromium, high concentrations of benzene series compounds and sulfides.

[0012] After adding the three-micro system, carbon dioxide is introduced into the reaction system to ensure the complete dissolution of nutrients, trace metals, and other nutrients in the mixed liquid. This facilitates the rapid reproduction and activation of the subsequent bacterial community. After 5-10 days of reaction, the system is controlled at a micro-oxygen level by adding oxygen. This micro-oxygen level is key to achieving synergistic effects between iron-based micro-electrolysis and anaerobic acidification. The addition of the hydrolysis acidification enhancer contains specific nutrient factors that can improve bacterial activity and demonstrate a significant synergistic effect, thereby improving the treatment effect of iron-based micro-electrolysis and anaerobic acidification. Ultimately, it provides a better comprehensive treatment effect for mixed industrial wastewater containing complexed chromium, sulfides, and high organic load.

[0013] Ultimately, the "three-micro" synergistic coupling process of hydrolysis acidification, micro-electrolysis filler enhancement, and introduction of hydrolysis acidification enhancer adopted in this application can efficiently remove more than 90% of complexed chromium from wastewater, with total chromium consistently below 0.5 mg / L, fully meeting emission requirements. It can effectively convert and treat polycyclic aromatic hydrocarbons such as phenol and hydroquinone, significantly reducing COD and sulfide concentrations in wastewater, alleviating the load on subsequent biochemical treatment, and improving the system's nitrogen and phosphorus removal stability. The COD removal rate is basically stable at around 80%, and the removal rates of ammonia nitrogen and sulfide reach 60% and 92%, respectively. The enhanced synergistic mechanism of the three phases significantly enhances the overall deep treatment capability of mixed wastewater.

[0014] Optionally, the anaerobic mixed bacteria additive consists of bacteria with a concentration of 10... 8The solution was prepared by mixing cfu / mL of Desulfomicrobium norvegicum, Acetobacter indonesiensis, Clostridium ultunense, and Acetobacterium wieringae in a volume ratio of 2:(1.8-2.2):(0.8-1.2):(0.8-1.2).

[0015] By adopting the above technical solutions, the Norwegian desulfurizing microbacterium (Desulfomicrobium norvegicum) can effectively remove sulfides from wastewater, and the addition of Indonesian acetic acid bacteria (Acetobacter indonesiensis) can generate more vinegar acid, thereby significantly improving the hydrolysis and acidification capacity of the system.

[0016] Optionally, anaerobic mixed bacteria additives can be inoculated into the wastewater to be treated at an inoculation rate of 5-8% (V / V).

[0017] By adopting the above technical solution, the anaerobic mixed bacteria additive of a specific volume in this application is selected in the anaerobic bacterial agent, which significantly improves the removal performance of wastewater hydrolysis and acidification.

[0018] Optionally, the enhanced microbial additive includes alkali-producing bacteria, acid-producing bacteria, and other bacteria in a volume ratio of 1:(0.8-1.2):(0.8-1.2);

[0019] The alkali-producing bacteria were obtained by mixing Bacillus licheniformis, Bacillus subtilis, and Bacillus megaterium in a volume ratio of 4:(2.8-3.2):(1.8-2.2).

[0020] The acid-producing bacteria were obtained by mixing Lactobacillus brevis, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter aceti, Gluconacetobacter hansenii, and Gluconacetobacter xylinus in a volume ratio of 2:(1.8-2.2):(1.8-2.2):(0.8-1.2):(0.8-1.2):(0.8-1.2).

[0021] Other bacteria were obtained by mixing Rhodobacter sphaeroides and Paracoccus denitrificans in a volume ratio of 1:(0.8-1.2).

[0022] Optionally, the enhanced microbial additive is inoculated into the wastewater to be treated at an inoculation rate of 3-5% (V / V).

[0023] By adopting the above technical solution, Bacillus licheniformis, which has strong hydrolytic enzyme activity, can produce more acidic substances, thereby enhancing the hydrolysis and acidification effect. After adding anaerobic mixed bacteria additive to the wastewater to be treated, 11 kinds of hydrolysis and acidification enhancing bacteria are also added, which can significantly improve the activity and diversity of microorganisms in the system, resulting in better wastewater treatment effect.

[0024] Optionally, the hydrolysis acidification enhancer includes the following raw materials in parts by weight:

[0025] Humic acid ammonium salt: 35-40 parts;

[0026] Pectin: 25-30 parts;

[0027] Sucrose: 15-20 parts;

[0028] Dipotassium hydrogen phosphate: 10-15 parts;

[0029] Vitamin B1: 0.5-1 serving;

[0030] Vitamin B2: 1-2 servings;

[0031] β-carotene: 0.5-1 part.

[0032] Optionally, the amount of the hydrolysis enhancer added is 0.2-0.3% of the volume of the wastewater to be treated, and the hydrolysis enhancer is added after being diluted at a concentration of 2000-3000 mg / L.

[0033] By adopting the above technical solution, after adding the hydrolysis enhancer at the above concentration and dosage, the removal rate of ammonia nitrogen is higher, increasing by 10%, and the system stability is significantly improved, reaching the optimal concentration range for synergistic effect. The hydrolysis acidification enhancer contains specific nutrient factors vitamin B1, vitamin B2, and β-carotene. Vitamin B1 is a growth factor required by many bacteria, vitamin B2 is an important component for microbial culture, and β-carotene can promote the growth of various microorganisms. In this application, the hydrolysis enhancer specifically adds the above-mentioned growth factors and nutrients, which can significantly improve the activity of the bacterial community, enhance the hydrolysis acidification effect, and demonstrate a significant synergistic effect, ultimately resulting in a better comprehensive treatment effect for wastewater.

[0034] Optionally, the porous pretreated ceramsite is prepared by the following method:

[0035] S1. Polyester raw materials are prepared by transesterification reaction using aromatic diacids and aliphatic diols as raw materials.

[0036] S2. The polyester raw material is heated and melted to 200-240℃ under nitrogen protection, and then extruded in multiple stages to form extruded strips. The extruded strips are then water-cooled and cured in water at 0-5℃ in a nitrogen atmosphere. After water-cooling and curing, they are cut into spherical ceramic particles and dried to produce porous pretreated ceramic particles.

[0037] By adopting the above technical solution, this application uses aromatic diacids and aliphatic diols as raw materials to prepare a special high molecular weight polyester. After subsequent water-cooling pore-forming treatment, the polyester exhibits good performance in forming fine cracks. After the ceramsite surface is treated by the water-cooling pore-forming process, a large number of open pores and channels are formed, significantly increasing the specific surface area. This provides conditions for achieving higher iron loading in subsequent atomic layer deposition technology. In addition, the use of a special high molecular weight polyester in this application is more conducive to forming a fine pore structure during the melt water-cooling process, which is beneficial to the high loading of iron elements. This is more conducive to the micro-electrolysis treatment of wastewater, and better synergistic with anaerobic acidification, resulting in a better comprehensive treatment effect for wastewater.

[0038] Optionally, in the preparation of porous pretreated ceramsite, the aromatic diacid in step S1 is a mixture of terephthalic acid and isophthalic acid with a mass ratio of 60:(30-50).

[0039] The aliphatic diol is a mixture of 1,4-butanediol and 1,6-hexanediol in a mass ratio of 55:(40-50).

[0040] The mass ratio of aromatic diacid to aliphatic diol is 1:(0.8-1.2).

[0041] By adopting the above technical solution and controlling the raw material ratio to obtain the required high molecular weight polyester raw material, it is more conducive to improving the performance of forming fine cracks during subsequent water-cooled pore induction treatment. Among them, isophthalic acid improves the toughness and flexibility of polyester, which is beneficial to the formation of microcracks during subsequent water-cooled pore induction treatment, while 1,4-butanediol and 1,6-hexanediol increase the flexibility of the polyester main chain. Finally, the polyester raw material has a better pore distribution after water-cooled pore induction, a higher iron loading, and better wastewater treatment effect.

[0042] Regarding the selection and addition ratio of aromatic diacids and aliphatic diols in this application, appropriate aromatic components are beneficial for the generation of microcracks during water cooling and pore formation. At the same time, the addition ratio of the two affects the flexibility and thermal stability of the ceramsite, thereby affecting the subsequent loading of nano-iron. If too much aliphatic diol is added, the polyester flexibility will be enhanced but the thermal stability will be reduced. If too much aromatic diacid is added, the polyester thermal stability will be enhanced but the brittleness will also be enhanced. Therefore, the aromatic diacids and aliphatic diols selected in this application within a specific ratio range result in ceramsite with better overall performance, which is more conducive to the subsequent loading of nano-iron.

[0043] Optionally, the transesterification operation for preparing polyester raw materials is as follows:

[0044] The raw material is heated and melted to 180±20℃, then an acidic catalyst is added, and the temperature is raised to 220±20℃. The reaction is carried out under reduced pressure of 0.08±0.02MPa for 2-3 hours, the reaction is terminated, and the temperature is lowered to obtain polyester raw material.

[0045] By adopting the above technical solution, controlling the reaction temperature and time, and in conjunction with controlling the raw material ratio, the desired high molecular weight polyester raw material can be obtained.

[0046] Optionally, the amount of acidic catalyst added is 0.1-0.5 wt% of the raw material.

[0047] By adopting the above technical solution, the transesterification reaction requires the participation of an acidic catalyst. When the amount of acidic catalyst added is too small, the catalytic effect is not obvious and the reaction is slow. However, when the amount added is too large, it leads to the formation of distillation products by side reactions, which is not conducive to obtaining the desired high molecular weight polyester.

[0048] Optionally, during atomic layer deposition, the porous pretreated ceramic particles are placed in a reactor with a pressure of 0.01-0.05 MPa and the temperature is controlled at 100-150℃, so that the nano-iron is evaporated and deposited onto the porous pretreated ceramic particles, wherein the amount of nano-iron added is 8-10% of the mass of the porous pretreated ceramic particles.

[0049] By employing the above technical solution, excessively high pressure will inhibit evaporation and deposition. Therefore, a lower pressure is selected to allow the nano-iron to evaporate and deposit onto the surface of the porous pretreated ceramic particles. Too low a temperature will also prevent evaporation, but too high a temperature will easily cause the nano-iron to agglomerate, which is detrimental to deposition. The porous pretreated ceramic particles deposit under the pressure and temperature conditions provided in this application to form an ideal deposition film.

[0050] Optionally, the surface of the iron-based modified ceramic particles obtained by loading nano-iron onto the porous pretreated ceramic particles is sprayed with an ethanol solution of silica-modified polyaniline, and then kept at 150±10℃ for 5-10 min and cooled to obtain micro-electrolysis filler.

[0051] By adopting the above technical solution, an ethanol solution of silica-modified polyaniline is sprayed onto the surface of iron-based modified ceramsite, which improves the conductivity and hydrophilicity of the filler. This increases the conductivity of the micro-electrolysis filler by more than 10 times, making it more effective in removing organic matter from wastewater and resulting in a better overall wastewater treatment effect.

[0052] Spraying an ethanol solution of silica-modified polyaniline onto the surface of iron-based modified ceramsite and then heat-treating it at a specific temperature can quickly and efficiently complete the cross-linking and curing of the coating. It also enhances the bonding force between the polyaniline film and the ceramsite matrix and avoids the oxidative degradation of polyaniline under high-temperature conditions.

[0053] In summary, this application has the following beneficial effects:

[0054] 1. This application employs surface-modified micro-electrolysis packing material, while utilizing the hydrolytic acid production effect of highly efficient anaerobic bacteria, and strictly controlling micro-aerobic conditions (DO<0.5mg / L) to efficiently remove complexed chromium, as well as recalcitrant organic matter and sulfides from wastewater from a synergistic physicochemical and biological perspective. Simultaneously, by adjusting the pH of the reaction system and utilizing the co-catalytic effect of a hydrolysis acidification enhancer, the wastewater to be treated is transformed and removed more efficiently and completely, achieving rapid removal and deep treatment of mixed industrial wastewater containing complexed chromium, high concentrations of benzene series compounds, and sulfides.

[0055] 2. This application employs a synergistic coupling process of hydrolysis acidification, micro-electrolysis filler enhancement, and the introduction of a hydrolysis acidification enhancer. This process can efficiently remove more than 90% of complexed chromium from wastewater, with total chromium levels consistently below 0.5 mg / L, fully meeting emission requirements. It can effectively convert and treat polycyclic aromatic hydrocarbons such as phenol and hydroquinone, significantly reducing COD and sulfide concentrations in wastewater, alleviating the load on subsequent biochemical treatment, and improving the system's nitrogen and phosphorus removal stability. The COD removal rate is basically stable at around 80%, while the removal rates of ammonia nitrogen and sulfides reach 60% and 92%, respectively. The enhanced synergistic mechanism of the three phases significantly enhances the overall deep treatment capability of mixed wastewater.

[0056] 3. In this application, a specially formulated high molecular weight polyester is prepared using aromatic diacids and aliphatic diols as raw materials. This polyester undergoes a subsequent water-cooling pore-forming treatment, resulting in good performance in forming fine cracks. After the ceramsite surface is treated with the water-cooling pore-forming process, a large number of open pores and channels are formed, significantly increasing the specific surface area. This provides conditions for achieving higher iron loading in subsequent atomic layer deposition technology. In addition, the specially formulated high molecular weight polyester used in this application is more conducive to forming a fine pore structure during the melt water-cooling process, which is beneficial to the high loading of iron elements. This is more conducive to the micro-electrolysis treatment of wastewater, and better synergistic with anaerobic acidification, resulting in a better comprehensive treatment effect for wastewater.

[0057] 4. Spraying an ethanol solution of silica-modified polyaniline onto the surface of iron-based modified ceramsite improves the conductivity and hydrophilicity of the filler, increasing the conductivity of the micro-electrolysis filler by more than 10 times. This is more conducive to removing organic matter from wastewater and provides a better overall treatment effect for wastewater. After spraying the ethanol solution of silica-modified polyaniline onto the surface of iron-based modified ceramsite, heat treatment at a specific temperature can quickly and efficiently complete the cross-linking and curing of the coating. It also enhances the bonding force between the polyaniline film and the ceramsite matrix and avoids the oxidative degradation of polyaniline under high temperature conditions. Detailed Implementation

[0058] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0059] The nano-iron particles used in this application are from commercially available sources and can also be obtained by the following methods. The nano-iron in the embodiments of this application is obtained by the following methods.

[0060] Preparation Example 1 is an example of preparing nano-iron, and Preparation Examples 2-4 are examples of preparing silica-modified polyaniline solutions.

[0061] The wastewater to be treated in the following examples is an industrial mixed simulated wastewater prepared by mixing a 100 mg / L hexavalent chromium solution with K2Cr2O7 as the chromium source, an organic mixed solution with phenol and o-methylphenol at a concentration of 3000 mg / L, and a sulfide solution with a concentration of 80 mg / L prepared with Na2S.

[0062] In the following examples, the Norwegian desulfurizing microbacterium, Desulfomicrobium norvegicum, was commercially available, product number: DSM1234;

[0063] Acetobacter indonesiensis, a commercially available product, product number: DSM15004;

[0064] The acetic acid oxidizing bacteria, Clostridium ultunense, is commercially available, product number: DSM10521;

[0065] Acetobacterium wieringae, commercially available, product number: DSM1911;

[0066] Bacillus licheniformis, commercially available, product number: DSM13;

[0067] Bacillus subtilis, commercially available, product number: DSM10;

[0068] Bacillus megaterium, commercially available, product number: DSM32;

[0069] Lactobacillus brevis, commercially available, product number: DSM12;

[0070] Lactobacillus fermentum, commercially available, product number: DSM20052;

[0071] Lactobacillus plantarum, commercially available, product number: DSM20174;

[0072] Acetobacter aceti, commercially available, product number: DSM3508;

[0073] Gluconacetobacter hansenii, commercially available, product number: DSM5602;

[0074] Gluconacetobacter xylinus, commercially available, product number: DSM2325;

[0075] Rhodobacter sphaeroides, commercially available, product number: DSM158;

[0076] Paracoccus denitrificans, commercially available, product number: DSM413.

[0077] Preparation Example 1

[0078] A method for preparing nano-iron particles includes the following steps:

[0079] 1 kg of ferric nitrate was dissolved in water to obtain a ferric nitrate solution. The pH of the ferric nitrate solution was adjusted to 4, and the concentration of the ferric nitrate solution was 0.1 mol / L.

[0080] Hydrogen gas was introduced into a ferric nitrate solution to induce a reduction reaction. The hydrogen gas flow rate was 80 mL / min, the reaction temperature was 70 °C, and the reaction time was 3 h.

[0081] After the reaction was completed, the particles were centrifuged, washed, and dried to obtain nano-iron particles with a particle size of 20-50 nm.

[0082] Preparation Example 2

[0083] A method for preparing a silica-modified polyaniline solution includes the following steps:

[0084] Based on 1 kg of silica sol, silica sol and hydrochloric acid solution were mixed at a volume ratio of 1:6 and ultrasonically dispersed to obtain diluted silica sol. An ethanol solution of aniline was added under stirring, and the temperature was controlled at 5℃. The amount of aniline added was 1.3 times the amount of silica sol added, and the amount of ethanol added was 4 times the amount of aniline added. At the same time, ammonium persulfate solution was added, and the amount of ammonium persulfate solution added was 5 wt% of the mass of aniline. The pH was adjusted to 2, and the reaction was stirred for 2 hours. After the reaction was stopped, the mixture was allowed to stand, filtered, washed with water, and dried to obtain silica-modified polyaniline.

[0085] The prepared silica-modified polyaniline was mixed with ethanol at a mass ratio of 1:12 to obtain a silica-modified polyaniline solution.

[0086] Preparation Example 3

[0087] A method for preparing a silica-modified polyaniline solution includes the following steps:

[0088] Based on 1 kg of silica sol, silica sol and hydrochloric acid solution were mixed at a volume ratio of 1:5 and ultrasonically dispersed to obtain diluted silica sol. An ethanol solution of aniline was added under stirring, and the temperature was controlled at 5℃. The amount of aniline added was 1.2 times the amount of silica sol added, and the amount of ethanol added was 3 times the amount of aniline added. At the same time, ammonium persulfate solution was added, and the amount of ammonium persulfate solution added was 3 wt% of the mass of aniline. The pH was adjusted to 1, and the reaction was stirred for 1.5 h. After the reaction was stopped, the mixture was allowed to stand, filtered, washed with water, and dried to obtain silica-modified polyaniline.

[0089] The prepared silica-modified polyaniline was mixed with ethanol at a mass ratio of 1:10 to obtain a silica-modified polyaniline solution.

[0090] Preparation Example 4

[0091] A method for preparing a silica-modified polyaniline solution includes the following steps:

[0092] Based on 1 kg of silica sol, silica sol and hydrochloric acid solution were mixed at a volume ratio of 1:8 and ultrasonically dispersed to obtain diluted silica sol. An ethanol solution of aniline was added under stirring, and the temperature was controlled at 5℃. The amount of aniline added was 1.5 times the amount of silica sol added, and the amount of ethanol added was 5 times the amount of aniline added. At the same time, ammonium persulfate solution was added, and the amount of ammonium persulfate solution added was 8 wt% of the mass of aniline. The pH was adjusted to 1, and the reaction was stirred for 2.5 h. After the reaction was stopped, the mixture was allowed to stand, filtered, washed with water, and dried to obtain silica-modified polyaniline.

[0093] The prepared silica-modified polyaniline was mixed with ethanol at a mass ratio of 1:15 to obtain a silica-modified polyaniline solution.

[0094] Example 1

[0095] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load includes the following steps:

[0096] 1) Preparation of iron-based micro-electrolysis filler: Based on an aromatic diacid addition of 10 kg, aromatic diacid and aliphatic diol were mixed at a mass ratio of 1:1 and added as raw materials. The mixture was heated to melt and the temperature was raised to 180℃. Then, an acidic catalyst (p-toluenesulfonic acid) was added, with the amount of acidic catalyst added being 0.3 wt% of the raw materials. The temperature was raised to 220℃ and the pressure was reduced to 0.08 MPa. During the pressure reduction process, the generated low-boiling alcohols were removed. The reaction was carried out under the pressure reduction condition of 0.08 MPa for 2.5 h. The reaction was terminated and the temperature was lowered to room temperature to obtain polyester raw materials. Among them, the aromatic diacid was a mixture of terephthalic acid and isophthalic acid with a mass ratio of 60:40, and the aliphatic diol was a mixture of 1,4-butanediol and 1,6-hexanediol with a mass ratio of 55:45.

[0097] The obtained polyester raw material is heated and melted to 220°C in a nitrogen atmosphere, and then extruded into extrusion strips with a diameter of 5-10 mm through a multi-stage extruder. The extrusion strips are rapidly water-cooled in a 3°C water-cooling tank under a nitrogen atmosphere. After water-cooling and solidification, they are cut into spherical ceramsite and dried to obtain porous pretreated ceramsite.

[0098] The porous pretreated ceramic particles and the nano-iron prepared in Preparation Example 1 were placed in a low-pressure reactor. The amount of nano-iron added was 9 wt% of the mass of the porous pretreated ceramic particles. The pressure inside the reactor was controlled at 0.03 MPa and the temperature at 120 °C. The nano-iron was evaporated and deposited onto the porous pretreated ceramic particles using the principle of atomic layer adhesion to obtain iron-based modified ceramic particles.

[0099] An ethanol solution of silica-modified polyaniline prepared in Example 2 was sprayed onto the surface of the obtained iron-based modified ceramic particles, kept at 150°C for 8 min, and then cooled to obtain an iron-based micro-electrolysis filler with a silica-modified polyaniline film with a thickness of 100 nm.

[0100] 2) Configure a complete 2 cubic meter reaction tank system. The iron-based micro-electrolysis packing material obtained in step 1) is filled into the reaction tank using a segmented filling method with corrugated baffles. A section of corrugated baffle is installed every 0.5 meters in height within the reaction tank as a support, dividing the iron-based micro-electrolysis packing material into several independent volumes. This filling method avoids packing material settling, increases the liquid-solid exchange area, improves the current efficiency of micro-electrolysis, and enhances the utilization efficiency of the packing material. The packing material loading is based on the reaction tank volume, specifically at 20 kg / m³. 3 Total loading capacity; the reaction tank is connected to an external micro-electrolysis power supply, which adopts a regulated DC power supply with a rated voltage of 0.8V and a maximum output current of 80A;

[0101] 3) Preparation of anaerobic bacterial agents:

[0102] Desulfomicrobium norvegicum, Acetobacter indonesiensis, Clostridium ultunense, and Acetobacterium wieringae were cultured separately in anaerobic medium. The logarithmic growth phase of each culture was collected, and then each strain was centrifuged, washed, and adjusted to a concentration of 10⁻⁶. 8 The concentration of cfu / mL was determined, and then the mixture was prepared into a colloidal anaerobic mixed bacteria additive by mixing them in a volume ratio of 2:2:1:1.

[0103] Bacillus licheniformis, Bacillus subtilis, Bacillus megaterium, Lactobacillus brevis, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter aceti, Gluconacetobacter hansenii, Gluconacetobacter xylinus, Rhodobacter sphaeroides, and Paraacoccus denitrificans were cultured separately, and the bacterial cultures during the proliferation phase were collected separately. Then, after individual centrifugation, washing, and concentration adjustment, each culture was adjusted to a concentration of 10. 8 The volume ratio of cfu / mL was then adjusted to obtain alkali-producing bacteria by mixing B. licheniformis: B. subtilis: B. megaterium = 4:3:2. Acid-producing bacteria were prepared by mixing L. brevis: L. fermentum: L. plantarum: A. aceti: ​​G. hansenii: G. xylinus = 2:2:2:1:1:1. Other bacteria were prepared by mixing R. sphaeroides: P. denitrificans = 1:1. Finally, alkali-producing bacteria, acid-producing bacteria and other bacteria were mixed in a volume ratio of 1:1:1 to prepare a paste-like fortified bacterial additive.

[0104] 4) Preparation of hydrolysis acidification enhancer: Prepare the hydrolysis acidification enhancer according to the following formula: 38 kg of humic acid ammonium salt; 28 kg of pectin; 18 kg of sucrose; 12 kg of dipotassium hydrogen phosphate; 0.8 kg of vitamin B1; 1.5 kg of vitamin B2; and 0.8 kg of β-carotene. 5) Start-up: Add the wastewater to be treated to the reaction tank in step 2), and inoculate the wastewater to be treated in the reaction tank in step 2) with the anaerobic mixed bacteria additive and the enhancer additive obtained in step 3). The anaerobic mixed bacteria additive is inoculated into the wastewater to be treated at a volume of 6% (V / V), and the enhancer additive is inoculated into the wastewater to be treated at a volume of 4% (V / V).

[0105] In step 2), the hydrolysis acidification enhancer prepared in step 4) is added to the wastewater to be treated in the reaction tank. The amount of hydrolysis acidification enhancer added is 0.25% of the volume of the wastewater to be treated, and the hydrolysis enhancer is added after being diluted at a concentration of 2500 mg / L.

[0106] Start the stirrer in the reaction tank to start the reaction. Control the temperature at 35℃ and the stirring rate at 80r / min. Introduce CO2 into the reaction system and control the pH value of the system to 6. Ensure that the nutrients, trace metals and other components in the mixed waste liquid are completely dissolved, which is conducive to the rapid reproduction and start-up of the subsequent microbial community.

[0107] After the system has been running for 7 days, the micro-oxygenation system is turned on, the DO is controlled at 0.3 mg / L, and the pH of the system is maintained at 6.

[0108] Example 2

[0109] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load, performed according to the method in Example 1, with the difference being that...

[0110] In step 1), aromatic diacid and aliphatic diol are mixed at a mass ratio of 1:0.8 and added as raw materials. The mixture is heated to melt and the temperature is raised to 160°C. Then, an acidic catalyst (p-toluenesulfonic acid) is added at a mass ratio of 0.1 wt% of the raw materials. The temperature is raised to 200°C and the pressure is reduced to 0.06 MPa. During the pressure reduction process, the low-boiling alcohols generated are removed. The reaction is carried out under the pressure of 0.06 MPa for 2 hours. The reaction is then terminated and the temperature is lowered to room temperature to obtain polyester raw materials. The aromatic diacid is a mixture of terephthalic acid and isophthalic acid at a mass ratio of 60:30, and the aliphatic diol is a mixture of 1,4-butanediol and 1,6-hexanediol at a mass ratio of 55:40.

[0111] The obtained polyester raw material is heated and melted to 200°C in a nitrogen atmosphere, and then extruded into extrusion strips with a diameter of 5-10 mm through a multi-stage extruder. The extrusion strips are rapidly water-cooled in a 1°C water-cooling tank under a nitrogen atmosphere. After water-cooling and solidification, they are cut into spherical ceramsite and dried to obtain porous pretreated ceramsite.

[0112] The porous pretreated ceramic particles and the nano-iron prepared in Preparation Example 1 were placed in a low-pressure reactor. The amount of nano-iron added was 8 wt% of the mass of the porous pretreated ceramic particles. The pressure inside the reactor was controlled at 0.01 MPa and the temperature at 100 °C. The nano-iron was evaporated and deposited onto the porous pretreated ceramic particles using the principle of atomic layer adhesion to obtain iron-based modified ceramic particles.

[0113] An ethanol solution of silica-modified polyaniline prepared in Example 3 was sprayed onto the surface of the obtained iron-based modified ceramic particles, kept at 140°C for 5 min, and then cooled to obtain an iron-based micro-electrolysis filler with a silica-modified polyaniline film with a thickness of 100 nm.

[0114] In step 3), *Desulfomicrobium norvegicum*, *Acetobacter indonesiensis*, *Clostridium ultunense*, and *Acetobacterium wieringae* were cultured, centrifuged, washed, and adjusted to 10⁻¹⁰. 8 The concentration of cfu / mL was determined, and then the mixture was prepared into a colloidal anaerobic mixed bacteria additive by mixing them in a volume ratio of 2:1.8:0.8:0.8.

[0115] Alkali-producing bacteria were prepared by mixing B. licheniformis: B. subtilis: B. megaterium in a volume ratio of 4:2.8:1.8. Acid-producing bacteria were prepared by mixing L. brevis: L. fermentum: L. plantarum: A. aceti: ​​G. hansenii: G. xylinus in a volume ratio of 2:1.8:1.8:0.8:0.8:0.8. Other bacteria were prepared by mixing R. sphaeroides: P. denitrificans in a volume ratio of 1:0.8. Finally, a paste-like fortified bacterial additive was prepared by mixing the alkali-producing bacteria, acid-producing bacteria and other bacteria in a volume ratio of 1:0.8:0.8.

[0116] In step 4), the hydrolysis acidification fortifier was prepared according to the following formula: 35 kg of humic acid ammonium salt; 25 kg of pectin; 15 kg of sucrose; 10 kg of dipotassium hydrogen phosphate; 0.5 kg of vitamin B1; 1 kg of vitamin B2; and 0.5 kg of β-carotene.

[0117] In step 5), the anaerobic mixed bacteria additive is inoculated into the wastewater to be treated at an inoculation rate of 5% (V / V), the strengthening bacteria additive is inoculated into the wastewater to be treated at an inoculation rate of 3% (V / V), and the amount of hydrolysis acidification strengthening agent added is 0.2% of the volume of the wastewater to be treated, and the hydrolysis strengthening agent is added after being diluted at a concentration of 2000 mg / L.

[0118] Start the stirrer in the reaction tank to start the reaction. Control the temperature at 35℃ and the stirring rate at 80r / min. Introduce CO2 into the reaction system and control the pH value of the system to 6. Ensure that the nutrients, trace metals and other components in the mixed waste liquid are completely dissolved, which is conducive to the rapid reproduction and start-up of the subsequent microbial community.

[0119] After the system has been running for 5 days, the micro-oxygenation system is turned on, and the DO is controlled at 0.2 mg / L, while the pH of the system is maintained at 6.

[0120] Example 3

[0121] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load, performed according to the method in Example 1, with the difference being that...

[0122] In step 1), an aromatic diacid and an aliphatic diol are mixed at a mass ratio of 1:1.2 and added as raw materials. The mixture is heated to melt and the temperature is raised to 200°C. Then, an acidic catalyst (p-toluenesulfonic acid) is added at a mass ratio of 0.5 wt% of the raw materials. The temperature is raised to 240°C and the pressure is reduced to 0.08 MPa. During the pressure reduction process, the low-boiling alcohols generated are removed. The reaction is carried out under a pressure of 0.08 MPa for 3 hours. The reaction is then terminated and the temperature is lowered to room temperature to obtain polyester raw materials. The aromatic diacid is a mixture of terephthalic acid and isophthalic acid at a mass ratio of 60:50, and the aliphatic diol is a mixture of 1,4-butanediol and 1,6-hexanediol at a mass ratio of 55:50.

[0123] The obtained polyester raw material is heated and melted to 240°C in a nitrogen atmosphere, and then extruded into extrusion strips with a diameter of 5-10 mm through a multi-stage extruder. The extrusion strips are rapidly water-cooled in a 5°C water-cooling tank under a nitrogen atmosphere. After water-cooling and solidification, they are cut into spherical ceramsite and dried to obtain porous pretreated ceramsite.

[0124] Porous pretreated ceramic particles and nano-iron prepared in Preparation Example 1 were placed in a low-pressure reactor. The amount of nano-iron added was 10 wt% of the mass of the porous pretreated ceramic particles. The pressure inside the reactor was controlled at 0.05 MPa and the temperature at 150 °C. The nano-iron was evaporated and deposited onto the porous pretreated ceramic particles using the principle of atomic layer adhesion to obtain iron-based modified ceramic particles.

[0125] An ethanol solution of silica-modified polyaniline prepared in Example 4 was sprayed onto the surface of the obtained iron-based modified ceramic particles, kept at 160°C for 10 min, and then cooled to obtain an iron-based micro-electrolysis filler with a silica-modified polyaniline film with a thickness of 100 nm.

[0126] In step 3), *Desulfomicrobium norvegicum*, *Acetobacter indonesiensis*, *Clostridium ultunense*, and *Acetobacterium wieringae* were cultured, centrifuged, washed, and adjusted to 10⁻¹⁰. 8 The concentration of cfu / mL was determined, and then the mixture was prepared into a colloidal anaerobic mixed bacteria additive by mixing the bacteria in a volume ratio of 2:2.2:1.2:1.2.

[0127] Alkali-producing bacteria were prepared by mixing B. licheniformis: B. subtilis: B. megaterium in a volume ratio of 4:3.2:2.2. Acid-producing bacteria were prepared by mixing L. brevis: L. fermentum: L. plantarum: A. aceti: ​​G. hansenii: G. xylinus in a volume ratio of 2:2.2:2.2:1.2:1.2:1.2. Other bacteria were prepared by mixing R. sphaeroides: P. denitrificans in a volume ratio of 1:1.2. Finally, alkali-producing bacteria, acid-producing bacteria and other bacteria were mixed in a volume ratio of 1:1.2:1.2 to prepare a paste-like fortified bacterial additive.

[0128] In step 4), the hydrolysis acidification fortifier was prepared according to the following formula: 40 kg of humic acid ammonium salt; 30 kg of pectin; 20 kg of sucrose; 15 kg of dipotassium hydrogen phosphate; 1 kg of vitamin B1; 2 kg of vitamin B2; and 1 kg of β-carotene.

[0129] In step 5), the anaerobic mixed bacteria additive is inoculated into the wastewater to be treated at an inoculation rate of 8% (V / V), the strengthening bacteria additive is inoculated into the wastewater to be treated at an inoculation rate of 5% (V / V), and the amount of hydrolysis acidification strengthening agent added is 0.3% of the volume of the wastewater to be treated, and the hydrolysis strengthening agent is added after being diluted at a concentration of 3000 mg / L.

[0130] Start the stirrer in the reaction tank to start the reaction. Control the temperature at 35℃ and the stirring rate at 80r / min. Introduce CO2 into the reaction system and control the pH value of the system to 7. Ensure that the nutrients, trace metals and other components in the mixed waste liquid are completely dissolved, which is conducive to the rapid reproduction and start-up of the subsequent microbial community.

[0131] After the system has been running for 10 days, the micro-oxygenation system is turned on, and the DO is controlled at 0.4 mg / L, while the pH of the system is maintained at 6.5.

[0132] Example 4

[0133] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load is carried out according to the method in Example 1, except that terephthalic acid is used as the aromatic diacid when preparing the iron-based micro-electrolysis packing in step 1).

[0134] Example 5

[0135] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load is carried out according to the method in Example 1, except that isophthalic acid is used as the aromatic diacid when preparing the iron-based micro-electrolysis packing in step 1).

[0136] Example 6

[0137] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load is carried out according to the method in Example 1, except that Norwegian desulfurizing bacteria are not added during the preparation of the anaerobic bacterial agent. Instead, Norwegian desulfurizing bacteria are replaced in equal volumes with Indonesian acetic acid bacteria, syntrophic acetic acid oxidizing bacteria, and Welsh acetic acid bacteria in a volume ratio of 2:1:1.

[0138] Example 7

[0139] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load is carried out according to the method in Example 1, except that when preparing the anaerobic bacterial agent, Indonesian acetic acid bacteria are not added, and Indonesian acetic acid bacteria are replaced by Norwegian desulfurizing microorganisms, synergistic acetic acid oxidizing bacteria, and Welsh acetic acid bacteria in equal volume ratios of 2:1:1.

[0140] Example 8

[0141] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load is carried out according to the method in Example 1, except that vitamin B1, vitamin B2, and β-carotene are not added to the raw materials when preparing the hydrolysis acidification enhancer in step 4).

[0142] Comparative Example 1

[0143] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load was carried out according to the method in Example 1, except that steps 1), 2), and 4) were not performed. In step 5), only the anaerobic mixed bacteria additive and the enhanced bacteria additive from step 3) were inoculated into the wastewater to be treated, and no iron-based micro-electrolysis filler and hydrolysis acidification enhancer were added. It was observed that after the initial 12 hours of operation, the COD removal rate was only 20%, and after 24 hours of further reaction, the COD removal rate was only 35%, and the COD removal rate slowed down significantly over time. The content and form of total chromium did not change significantly, and no signs of chromium removal reaction were observed. After 48 hours of further reaction, the COD removal rate remained below 45%, and the removal effect on organic matter was not ideal. At the same time, the removal rate of complexed chromium was below 15%, and the removal rate of sulfides was 20%. It can be seen that the single hydrolysis acidification process is difficult to effectively treat complex industrial wastewater containing chromium, high COD, and sulfides.

[0144] Comparative Example 2

[0145] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load was carried out according to the method in Example 1, except that steps 4) and 5) were not performed, and no hydrolysis acidification enhancer was added. Only anaerobic mixed bacteria additives, enhancer additives, and iron-based micro-electrolysis packing were added. It was found that after 6 hours of operation, the COD removal rate increased to 45% and basically stabilized after 24 hours. The removal rate of complexed chromium increased to 25%, which was improved but still low. The removal rate of sulfides was 30%. In the later stage, the removal rates of various indicators declined and gradually leveled off. It can be seen that the micro-electrolysis packing significantly enhanced the overall removal of the hydrolysis acidification system, but the deep removal effect on recalcitrant organic matter and heavy metals was still low.

[0146] Comparative Example 3

[0147] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load is carried out according to the method in Example 1, except that steps 3) and 4) are not performed, and anaerobic mixed bacteria additives, enhanced bacteria additives, and hydrolysis acidification enhancers are not added in step 5). Only iron-based micro-electrolysis packing is used to treat the wastewater.

[0148] Comparative Example 4

[0149] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load is carried out according to the method in Example 1, except that in step 1), when preparing the iron-based micro-electrolysis filler, the surface of the obtained iron-based modified ceramic particles is not sprayed with an ethanol solution of silica-modified polyaniline, and is directly used as the iron-based micro-electrolysis filler.

[0150] Comparative Example 5

[0151] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load is carried out according to the method in Example 1, except that in step 1), when preparing the iron-based micro-electrolysis filler, the ethanol solution of silica-modified polyaniline sprayed on the surface of the iron-based modified ceramic particles is directly replaced by an equal amount of ethanol solution of polyaniline, and polyaniline and ethanol are mixed at a mass ratio of 1:12.

[0152] Comparative Example 6

[0153] A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load, is carried out according to the method in Example 1, except that step 1) the iron-based micro-electrolysis packing is prepared by the following method:

[0154] Weigh out 34 kg of iron powder, 20 kg of iron filings, 18 kg of activated carbon powder, 12 kg of lime powder, 6 kg of alumina, 7 kg of bentonite, and 3 kg of sodium carbonate. Mix them with water and press them into oval semi-finished products under 220 KN pressure in a roller press. Then dry them at 120℃ for 14 h and place them in a muffle furnace. Calcinate them at 500℃ for 3 h in a nitrogen atmosphere. Cool them in the furnace to below 100℃ and then remove them and let them cool naturally to room temperature to obtain iron-based micro-electrolysis filler. The iron-based micro-electrolysis filler loaded in step 2) is the iron-based micro-electrolysis filler prepared above.

[0155] Performance testing

[0156] The mixed industrial wastewater was treated according to the methods in the above embodiments and comparative examples. After 36 hours of treatment, the following indicators of the wastewater were tested. The test results of the wastewater treatment are shown in Table 1 below.

[0157] Table 1:

[0158] Testing items Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 COD removal rate / % 87 82 83 73 77 74 Sulfide removal rate / % 94 90 92 83 88 76 Complexed chromium removal rate / % 96 93 95 85 87 85 Testing items Example 7 Example 8 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 COD removal rate / % 75 72 48 53 60 51 Sulfide removal rate / % 86 84 40 53 61 59 Complexed chromium removal rate / % 88 86 36 48 64 60

[0159] Referring to the test results in Table 1 above, it can be seen that when using the methods in Examples 1-3 of this application to treat mixed industrial wastewater, the COD removal rate reaches over 80%, the removal rate of complexed chromium is significantly increased to over 90%, the total chromium is stabilized below 0.5 mg / L, the sulfide removal rate also reaches over 90%, the ammonia nitrogen removal rate reaches over 60%, and the TOC removal rate of the wastewater reaches over 50%, compared to only 30% for commercial packing materials on the market. Compared to Comparative Examples 1 and 2, which use anaerobic bacteria for hydrolysis acidification or hydrolysis acidification + micro-electrolysis composite treatment of wastewater, the anaerobic bacteria, hydrolysis acidification enhancer, and micro-electrolysis three-micro system in this application work synergistically, resulting in excellent overall comprehensive treatment effect for mixed industrial wastewater.

[0160] Referring to the test results of Examples 1, 4, and 5, it can be seen that when terephthalic acid or isophthalic acid is used as the aromatic diacid, the removal rate of COD in wastewater is significantly reduced. Combining the test results of Examples 1 and 6, it can be seen that when Norwegian desulfurizing microorganisms are not added to the anaerobic bacteria, the desulfurization effect on wastewater is significantly reduced. Referring to the test results of Example 7, it can be seen that when Indonesian acetic acid bacteria are not added to the anaerobic bacteria, the removal rate of COD in wastewater is significantly reduced. Referring to the test results of Example 8, it can be seen that when vitamin B1, vitamin B2, and β-carotene nutrients are not added to the hydrolysis acidification enhancer, the overall treatment effect on wastewater is reduced.

[0161] Combining the test results of Example 1 and Comparative Example 3, it can be seen that when only micro-electrolysis technology is used to treat wastewater, the COD removal rate, sulfide removal rate, and total chromium removal rate are all significantly reduced. Referring to the test results of Comparative Example 4 and Comparative Example 5, when the surface of the iron-based modified ceramsite is not coated with a silica-modified polyaniline coating or is coated with a common polyaniline coating, the COD removal rate is significantly reduced, and other indicators are also reduced. Referring to the test results of Comparative Example 6, it can be seen that when the iron-based micro-electrolysis filler is prepared by physically mixing common iron powder and activated carbon powder, the COD removal rate is low, and other indicators are also reduced.

[0162] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load, characterized in that, Includes the following steps: Anaerobic bacteria, hydrolysis acidification enhancer, and micro-electrolysis packing were added to the wastewater to be treated. The mixture was stirred, and CO2 was introduced into the reaction system. After running for 5-10 days, the dissolved oxygen (DO) was controlled to be 0.3±0.1 mg / L by adding oxygen. The micro-electrolysis filler is prepared by loading nano-iron onto the surface of porous pretreated ceramsite through atomic layer deposition and then spraying it with a silica-modified polyaniline film. The porous pretreated ceramsite is prepared by the following method: S1. Polyester raw materials are prepared by transesterification reaction using aromatic diacids and aliphatic diols as raw materials. S2. The polyester raw material is heated and melted to 200-240℃ under nitrogen protection, and then extruded in multiple stages to form extruded strips. The extruded strips are then water-cooled and cured in water at 0-5℃ in a nitrogen atmosphere. After water-cooling and curing, they are cut into spherical ceramsite and dried to produce porous pretreated ceramsite. During atomic layer deposition (ALD) of porous pretreated ceramic particles, the porous pretreated ceramic particles and nano-iron particles are placed in a reactor with a pressure of 0.01-0.05 MPa and a temperature of 100-150℃, so that the nano-iron is evaporated and deposited onto the porous pretreated ceramic particles. The amount of nano-iron particles added is 8-10% of the mass of the porous pretreated ceramic particles. The surface of the iron-based modified ceramic particles obtained by loading nano-iron onto porous pretreated ceramic particles was sprayed with an ethanol solution of silica-modified polyaniline, and then kept at 150±10℃ for 5-10 min and cooled to obtain micro-electrolysis filler. Anaerobic bacteria agents include anaerobic mixed bacteria additives and fortifying bacteria additives. Anaerobic mixed bacteria additives mainly include sulfate-reducing bacteria and acetic acid-producing bacteria, while fortifying bacteria additives mainly include alkali-producing bacteria and acid-producing bacteria. Hydrolysis acidification fortifiers mainly include humic acid ammonium salts, pectin, and sucrose.

2. The method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load according to claim 1, characterized in that: The anaerobic mixed bacteria additive comprises bacteria with a concentration of 10... 8 The bacterial suspensions of Norwegian desulfurizing bacteria, Indonesian acetic acid bacteria, syntrophic acetic acid oxidizing bacteria and Welsh acetic acid bacteria (cfu / mL) were prepared by mixing in a volume ratio of 2:(1.8-2.2):(0.8-1.2):(0.8-1.2).

3. The method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load according to claim 1, characterized in that: The enhanced microbial additive includes alkali-producing bacteria, acid-producing bacteria, and other bacteria in a volume ratio of 1:(0.8-1.2):(0.8-1.2); The alkali-producing bacteria were obtained by mixing Bacillus licheniformis, Bacillus subtilis, and Bacillus megaterium in a volume ratio of 4:(2.8-3.2):(1.8-2.2). The acid-producing bacteria were obtained by mixing Lactobacillus brevis, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter, Gluconobacterium acetate, and Acetobacter xylinum in a volume ratio of 2:(1.8-2.2):(1.8-2.2):(0.8-1.2):(0.8-1.2):(0.8-1.2). Other bacteria were obtained by mixing Rhodobulobacterium spheroidum and Paracoccus denitrified at a volume ratio of 1:(0.8-1.2).

4. The method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load according to claim 1, characterized in that: Anaerobic mixed bacteria additive is inoculated into the wastewater to be treated at an inoculation rate of 5-8% by volume. The enhanced microbial additive is inoculated into the wastewater to be treated at an inoculation rate of 3-5% by volume.

5. The method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load according to claim 1, characterized in that: The hydrolysis acidification enhancer comprises the following raw materials in parts by weight: Humic acid ammonium salt: 35-40 parts; Pectin: 25-30 parts; Sucrose: 15-20 parts; Dipotassium hydrogen phosphate: 10-15 parts; Vitamin B1: 0.5-1 serving; Vitamin B2: 1-2 servings; β-carotene: 0.5-1 part.

6. The method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load according to claim 1, characterized in that: The amount of the hydrolysis acidification enhancer added is 0.2-0.3% of the volume of the wastewater to be treated, and the hydrolysis acidification enhancer is added after being diluted at a concentration of 2000-3000 mg / L.

7. The method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load according to claim 1, characterized in that: In the preparation of porous pretreated ceramsite, the aromatic diacid in step S1 is a mixture of terephthalic acid and isophthalic acid with a mass ratio of 60:(30-50). The aliphatic diol is a mixture of 1,4-butanediol and 1,6-hexanediol in a mass ratio of 55:(40-50); The mass ratio of aromatic diacid to aliphatic diol is 1:(0.8-1.2).

8. The method for treating mixed industrial wastewater containing complexed chromium, sulfides, and high organic load according to claim 1, characterized in that: The transesterification process for preparing polyester raw materials is as follows: The raw material is heated and melted to 180±20℃, then an acidic catalyst is added, and the temperature is raised to 220±20℃. The reaction is carried out under reduced pressure of 0.08±0.02MPa for 2-3 hours, the reaction is terminated, and the temperature is lowered to obtain polyester raw material.