CN113683272B - Advanced treatment system and method for polyurethane wastewater - Google Patents

Advanced treatment system and method for polyurethane wastewater Download PDF

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CN113683272B
CN113683272B CN202111247053.XA CN202111247053A CN113683272B CN 113683272 B CN113683272 B CN 113683272B CN 202111247053 A CN202111247053 A CN 202111247053A CN 113683272 B CN113683272 B CN 113683272B
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filler
modified
wastewater
polyurethane
stainless steel
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CN113683272A (en
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栗鸿强
吴雅琴
杨波
张高旗
王伟
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Hangzhou Water Treatment Technology Development Center Co Ltd
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Hangzhou Water Treatment Technology Development Center Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
    • B01J20/14—Diatomaceous earth
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
    • C02F1/4672—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46133—Electrodes characterised by the material
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/34—Organic compounds containing oxygen
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
    • C02F2103/38—Polymers
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/08—Aerobic processes using moving contact bodies
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/10—Packings; Fillings; Grids
    • C02F3/105—Characterized by the chemical composition
    • C02F3/108—Immobilising gels, polymers or the like
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/12—Activated sludge processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Abstract

The invention relates to an advanced treatment system for polyurethane wastewater, which is provided with a suspended filler biochemical pool, a three-dimensional electrooxidation device and a filler adsorption tower along the water flow direction; the biochemical pool of the suspended filler is filled with hydrophilic suspended filler with the density of 0.92-0.99g/cm3The porosity is 75-85%, the specific surface area is 800-840m2/m3The filling volume percentage is 33-37%; the microbial flora inoculated by the suspended filler biochemical pool comprises proteobacteria, bacteroidetes, pseudomonas and acidobacteroidetes; the upper part of the three-dimensional electrooxidation device is provided with a plurality of modified stainless steel electrodes, and modified fillers are filled in the three-dimensional electrooxidation device; the oxygen evolution potential of the modified stainless steel electrode relative to a silver/silver chloride standard hydrogen electrode is 1.25-1.45V; the specific surface area of the modified filler is 345-411m2The filling volume percentage of the modified active coke filling material is 25-35%. The filler adsorption tower is filled with modified diatomite filler with the specific surface area of 358-2The filling rate is 80-85 percent per kg. The invention can reduce COD in the polyurethane wastewater by more than 99.3 percent, reduce the concentration of formaldehyde by more than 99.95 percent and reduce acetone by more than 99.89 percent.

Description

Advanced treatment system and method for polyurethane wastewater
Technical Field
The invention relates to the technical field of wastewater treatment, in particular to a polyurethane wastewater advanced treatment system and a polyurethane wastewater advanced treatment method.
Background
China is the first major country for polyurethane production and sale in the world, and produced polyurethane materials such as soft foams, hard foams, elastomers, spandex, synthetic leather slurry and the like are widely applied to the industries such as traffic, furniture, buildings, clothes and the like.
Polyurethane can produce a large amount of waste water in the production process, and compared with other waste water, polyurethane production waste water has the following three remarkable characteristics: firstly, the pollutant content in the wastewater is generally high and the components are complex, and the direct discharge can unbalance the acid and alkali of the environment; secondly, pollutants in the wastewater are mostly compounds such as aldehydes, organic acids, inert solvents and the like, the stability is high, the degradation is difficult, the biochemical degradation time is long, and meanwhile, the contained formaldehyde with high concentration has high toxicity, so that microorganisms in water can die, genetic substances in cells can be damaged, the substances are suspicious carcinogens, if the substances are not treated, the water quality of the water body can be deteriorated, the ecological environment is influenced, and great harm can be brought to human health; and thirdly, the discharge amount of the wastewater and the change of the water quality are large, for example, the COD concentration (unit: mg/L) in the water body can fluctuate and change within the range of thousands to tens of thousands. Therefore, the treatment of the polyurethane wastewater to ensure that the wastewater reaches the discharge standard has important significance for protecting the ecological environment and the human health. The development of the high-efficiency treatment method of the polyurethane wastewater is beneficial to the high-efficiency emission reduction of pollutants and the reduction of the pollutant discharge pressure of chemical enterprises.
Disclosure of Invention
Technical problem to be solved
In view of the problems in the prior art, the invention provides a polyurethane wastewater advanced treatment system and a polyurethane wastewater advanced treatment method, which are used for efficiently reducing COD (chemical oxygen demand), formaldehyde content and acetone content in polyurethane wastewater, realizing advanced treatment of polyurethane wastewater, reducing pollution of polyurethane wastewater to the environment and reducing pollutant discharge pressure of chemical enterprises.
(II) technical scheme
In order to achieve the purpose, the invention adopts the main technical scheme that:
in a first aspect, the invention provides a polyurethane wastewater deep treatment system, which is provided with a suspended filler biochemical pool, a three-dimensional electrooxidation device and a filler adsorption tower along a water flow direction;
the biochemical pool of the suspended filler comprises a biochemical pool and hydrophilic suspended filler filled in the biochemical pool, and the biochemical pool also contains activated sludge; the density of the hydrophilic suspended filler is 0.92-0.99g/cm3The porosity is 75-85%, the specific surface area is 800-3The filling body in the biochemical poolThe volume percentage is 33-37%; the microbial flora in the activated sludge and the hydrophilic suspended filler comprises proteobacteria, bacteroidetes, bacillus monads and acidobacteroidetes;
the three-dimensional electrooxidation device comprises an electrolytic bath, wherein a plurality of modified stainless steel electrodes are arranged at the upper part of the electrolytic bath, and modified fillers are filled in the electrolytic bath; the oxygen evolution potential of the modified stainless steel electrode relative to a silver/silver chloride standard hydrogen electrode is 1.25-1.45V; the modified filler is modified active coke filler with specific surface area of 345 and square meter per gram (411), and the filling volume percentage of the modified active coke filler in the electrolytic cell is 25-35%;
the filler adsorption tower comprises a tower body and a modified diatomite filler filled in the tower body, and the filling volume percentage is 80-85%; the specific surface area of the modified diatomite filler is 358-405 square meters per kg.
Wherein, the height of tower body and the diameter ratio are 4-6: 1.
the absolute oxygen evolution potential is about 0.199V added to the oxygen evolution potential of the standard hydrogen electrode relative to silver/silver chloride, and therefore, when the relative (Ag/AgCl) oxygen evolution potential is 1.25-1.45V, the absolute oxygen evolution potential is 1.449-1.649V after conversion.
According to a preferred embodiment of the present invention, the hydrophilic suspended filler is a modified polyethylene filler, and the modified polyethylene filler is obtained by adding an oxygen-containing polar group and a hydrophilic polymer during the filler production process, thereby improving the affinity of the modified polyethylene filler for biological bacteria.
According to the preferred embodiment of the invention, the relative abundance of the microbial flora in the activated sludge and the hydrophilic suspended filler in the biochemical pool is 34-45% of Proteobacteria, 5-9% of Bacteroides, 4-7% of Buomonas and 3-6% of Acidobacterium; the microbial flora in the hydrophilic suspended filler is the same as that in the activated sludge, and the relative abundance is higher than that of the activated sludge.
According to the preferred embodiment of the present invention, the microbial flora inside the hydrophilic suspended filler is Proteobacteria with relative abundance of 42-58%, Bacteroides with relative abundance of 7-14%, Baculomonas with relative abundance of 6-9% and Acidobacterium with relative abundance of 4-7%.
According to the bookIn a preferred embodiment of the invention, the modified polyethylene filler is cylindrical, has a diameter of 20mm, a height of 8mm and a density of 0.96g/cm3The porosity is 80%, and the specific surface area is 820 square meters per meter3。
According to a preferred embodiment of the invention, the modified stainless steel electrode is a ruthenium manganese oxide modified stainless steel electrode, and preferably, the modified stainless steel electrode has an oxygen evolution potential of 1.35V relative to a silver/silver chloride standard hydrogen electrode.
According to the preferred embodiment of the invention, the total volume of the modified stainless steel electrodes accounts for 15-25% of the volume of the electrolytic cell, and the distance between adjacent electrodes is 1-2 cm.
According to a preferred embodiment of the present invention, the modified activated coke filler is a ferro-manganese modified activated coke filler.
According to a preferred embodiment of the present invention, in the filler adsorption tower, the modified diatomite filler is aluminum sulfate activated biochar-diatomite filler.
According to a preferred embodiment of the invention, the system further comprises a water intake pump, a plurality of lift pumps and a water discharge pump.
In a second aspect, the present invention provides an advanced treatment method for polyurethane wastewater, which comprises three treatment processes:
firstly, raw water of polyurethane wastewater is conveyed into a suspended filler biochemical pool, and the contents of COD, formaldehyde and acetone in the polyurethane wastewater are reduced under the combined action of activated sludge in the suspended filler biochemical pool and active biological bacteria in hydrophilic suspended filler;
the flow velocity of the polyurethane wastewater raw water in the suspended filler biochemical pool is 1.7-1.9m3The hydraulic retention time is 17-27h, and the volume load is 3.2-3.6 kg/(m)3D) dissolved oxygen of 3.4-4.2 mg/L;
then, the effluent of the suspended filler biochemical pool enters a three-dimensional electro-oxidation device, and the COD, formaldehyde and acetone contents of the polyurethane wastewater are further reduced by coupling the enhanced adsorption effect of the modified active coke filler in the electrolytic bath through the electrolytic reaction of the three-dimensional electro-oxidation device;
wherein the retention time of water power in the three-dimensional electro-oxidation device is 35-50min, and the current density is 2.7-3.2A/square meter;
finally, the effluent of the three-dimensional electrooxidation device enters a filler adsorption tower, and the hydraulic retention time is 35-60 min; the COD, formaldehyde and acetone contents of the polyurethane wastewater are reduced again through the adsorption effect of the modified diatomite filler; the effluent of the filler adsorption tower is discharged or converged into a general wastewater treatment system.
According to the preferred embodiment of the invention, the raw water quality of the polyurethane wastewater is characterized in that: the pH value is 6.9-7.7, the COD is 2270-4520mg/L, the formaldehyde content is 23-31mg/L, and the acetone content is 12-19 mg/L; the effluent quality of the filler adsorption tower is characterized in that: the pH value is 7.0-7.4, the COD is 16-28mg/L, the formaldehyde content is 0.01-0.03mg/L, and the acetone content is 0.01-0.02 mg/L.
According to the preferred embodiment of the invention, the preparation method of the modified stainless steel electrode comprises the following steps:
(1) mixing 1.5-2.7mol/L manganese nitrate solution and 0.4-1.2mol/L ruthenium chloride solution to obtain ruthenium-manganese mixed solution;
(2) adding 350-500mg of oxy-ferric chloride powder into each liter of ruthenium-manganese mixed solution, and carrying out ultrasonic and magnetic stirring for 35-45min to form iron-ruthenium-manganese mixed solution;
(3) polishing the surface of the stainless steel electrode, and removing surface impurities and organic substances to obtain the stainless steel electrode with a smooth surface;
(4) dipping the stainless steel electrode in the iron-ruthenium-manganese mixed solution obtained in the step (3) for 30-50min, then preserving the heat for 0.5-1h at the temperature of 130-; and (5) executing the step 4-6 times to obtain the modified stainless steel electrode.
Preferably, the oxygen evolution potential of the stainless steel electrode before modification is 0.88-0.92V (relative to the oxygen evolution potential value of a silver/silver chloride standard hydrogen electrode), and after modification, the oxygen evolution potential of the modified stainless steel electrode is 1.25-1.45V (relative to the oxygen evolution potential value of the silver/silver chloride standard hydrogen electrode). The modified stainless steel electrode is prepared according to the water quality characteristics of polyurethane wastewater. Through modification, the oxygen evolution potential is improved, more hydroxyl free radicals are generated, and the organic matter degradation capability is stronger. The preparation method of the iron oxychloride powder comprises the following steps: heating industrial-grade ferric trichloride to 215 ℃ at the temperature of 6-9 ℃/min, preserving heat for 1.5h, naturally cooling to obtain an iron oxychloride block, and then grinding to obtain iron oxychloride powder.
According to the preferred embodiment of the invention, the preparation method of the modified activated coke filler comprises the following steps:
(1) preparing a 123-235mg/L ferric trichloride solution and a 35-55mg/L manganese sulfate solution, and mixing the two solutions according to a volume ratio of 3-4:1 to form a ferro-manganese mixed solution;
(2) taking cylindrical active coke with the diameter of 2-4mm, immersing the active coke in the iron-manganese mixed solution for 12-16h, taking out the active coke, heating to 400-420 ℃ at the speed of 8-10 ℃/min, preserving the heat for 2.5-3.5h, and cooling to obtain the modified active coke filler. The modified active coke filler is prepared according to the characteristics of polyurethane wastewater. The specific surface area of the active coke filler is improved through modification, so that the capacity of adsorbing organic matters is improved.
According to the preferred embodiment of the invention, the preparation method of the modified diatomite filler comprises the following steps:
(1) sieving diatomite with a particle size of 0.5-0.8mm, sieving biochar with a particle size of 1-2mm, mixing the diatomite and the biochar according to a volume ratio of 6-9:1, and mechanically stirring for 10-15min to form a diatomite-biochar mixture;
(2) 345 and 521mg/L of aluminum sulfate solution are prepared, and 4-6g of diatomite-charcoal mixture is added into each liter of aluminum sulfate solution;
(3) and (3) radiating the mixed solution for 15-20min under the condition of microwave power of 700-1000W, stirring for 25-45min, and filtering to obtain the modified diatomite filler. The adsorption capacity of the diatomite filler to organic matters is improved through modification. The aluminum sulfate used for modification cannot be replaced by aluminum chloride, which would otherwise result in the increase of chloride ions in the water. And chloride ions are very corrosive.
(III) advantageous effects
The system provided by the invention is adopted for treating the polyurethane wastewater, so that the COD value in the polyurethane wastewater is reduced by more than 99.3%, the formaldehyde content is reduced by more than 99.95%, the acetone content is reduced by more than 99.89%, the treatment steps are simple, only three steps of treatment including a suspended filler biochemical pool, a three-dimensional electrooxidation device and a filler adsorption tower are included, the management is simplified, and the investment cost of enterprises is reduced.
The main technical innovation points of the invention comprise:
(1) the hydrophilic suspended filler is used in the suspended filler biochemical pool to inoculate microbial flora including proteobacteria, bacteroidetes, pseudomonas and acidobacteroidetes, and the suspended filler can move around along with water flow and has extremely high specific surface area and large porosity. The hydrophilicity of the filler greatly improves the affinity of the filler to microorganisms, so that the microorganisms are easily adsorbed on the surface of the filler to form a bacterial film. The large specific surface area is favorable for improving the contact area of the filler and organic matters and biological bacteria in the wastewater, improving the biochemical degradation efficiency, and reducing the dead angle of the biochemical tank due to the suspension property. The large porosity reduces the water flow resistance, is beneficial to the water flow to wash away the aged biological membrane and promote the updating of the biological membrane, and ensures that the whole biochemical degradation performance of the suspended filler biochemical tank is kept high-efficiency. The flora composed of multiple strains has good degradation capability for COD, aldehyde and ketone in the polyurethane wastewater.
(2) The modified active coke filler and the modified stainless steel electrode are used simultaneously in the three-dimensional electro-oxidation device. The reinforced adsorption process of the modified active coke filler is coupled with the electrochemical oxidation process, so that the efficiency of the three-dimensional electrooxidation device for treating the polyurethane wastewater is greatly improved. The modified stainless steel electrode and the active coke filler are modified according to the water quality characteristics of polyurethane wastewater, and the oxygen evolution potential of the stainless steel electrode can be improved through modification, so that the electrolytic oxidation efficiency is improved; the active coke filler is modified to increase the specific surface area and greatly improve the adsorption performance. On one hand, the filler adsorption has the function of reducing COD, aldehyde, ketone and the like in the wastewater, and on the other hand, the modified active coke filler enables organic matters in the wastewater to stay in an electrolytic bath for a longer time and be completely electrolyzed and oxidized.
(3) In the part of the filler adsorption tower, modified diatomite filler with high filling ratio is used for strengthening adsorption. The modified diatomite filler is modified and prepared according to the characteristics of polyurethane wastewater, and comprises the steps of compounding certain unfavorable biochar, activating by aluminum sulfate to obtain an activated biochar-diatomite filler, and further effectively reducing the contents of COD, formaldehyde and acetone in the wastewater subjected to three-dimensional electrooxidation treatment by taking the modified filler as the reinforced adsorption of the final stage, so that the content of formaldehyde/acetone in the effluent is far lower than the emission index value of related wastewater, and the emission standard is met.
Drawings
FIG. 1 is a schematic view showing the composition of an advanced polyurethane wastewater treatment system according to the present invention.
FIG. 2 is a graph showing the performance of a modified stainless steel electrode of a three-dimensional electrooxidation device in an advanced polyurethane wastewater treatment system according to the present invention.
Description of the symbols:
1. a water inlet pump; 2. a suspended filler biochemical tank; 3. a hydrophilic suspended filler; 4. a primary lift pump; 5. a three-dimensional electro-oxidation device; 6. a modified stainless steel electrode; 7. modifying active coke filler; 8. a secondary lift pump; 9. a packed adsorption column; 10. modified diatomite filler; 11. and (7) draining the pump.
Detailed Description
For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.
As shown in FIG. 1, a schematic view of an advanced treatment system for polyurethane wastewater according to the present invention. The polyurethane wastewater deep treatment system is mainly formed by sequentially connecting a suspended filler biochemical pool 2, a three-dimensional electrooxidation device 5 and a filler adsorption tower 9. The polyurethane wastewater raw water is conveyed to a suspended filler biochemical pool 2 by a water inlet pump 1, is subjected to degradation by active bacteria in the suspended filler biochemical pool 2, is conveyed to a three-dimensional electrooxidation device 5 by a primary lift pump 4, is subjected to electrooxidation treatment by the three-dimensional electrooxidation device 5, is conveyed to a filler adsorption tower 9 by a secondary lift pump 8, and is subjected to adsorption treatment by the filler adsorption tower 9 and then is discharged by a drainage pump 11.
The biochemical pool 2 of the suspension filler comprises a biochemical pool and a hydrophilic suspension filler 3 filled in the biochemical pool, and the biochemical pool also contains activated sludge. The density of the hydrophilic suspended filler 3 is 0.92-0.99g/cm3The density is close to that of water, and the hydrophilic suspended filler 3 can be suspended under the condition of slow stirring and can move along with the water flowAnd (6) moving. The porosity of the hydrophilic suspended filler 3 is 75-85%, and the specific surface area is 800-3The filling volume percentage of the biochemical pool is 33-37%.
The hydrophilic suspended filler 3 can be specifically a modified polyethylene filler, namely, substances such as oxygen-containing polar groups, hydrophilic polymers and the like are doped in the process of preparing the modified polyethylene filler, so that the prepared hydrophilic suspended filler 3 has hydrophilicity, the affinity of the modified polyethylene filler to microorganisms is greatly improved, and the microorganisms are easily adsorbed on the surface of the filler to form a bacterial film. Preferably, the modified polyethylene filler is cylindrical, diameter 20mm, height 8mm, density 0.96g/cm gauge, porosity 80% having a specific surface area obtained 820 m. The high specific surface area provides an excellent living environment for the microorganisms. The large porosity is beneficial to the washing of water flow, takes away aged biological membranes, updates the biological membranes and keeps the high efficiency of the whole biochemical pool.
In the process of stably treating polyurethane wastewater in the suspended filler biochemical pool 2, the relative abundance of the microbial flora in the activated sludge in the biochemical pool is 34-45% of proteobacteria, 5-9% of bacteroidetes, 4-7% of pseudomonas and 3-6% of acidibacterium. And the modified polyethylene filler has better affinity with microorganisms, so that in the modified polyethylene filler, the relative abundance of the phylum of the microorganisms is 42-58% of that of proteobacteria, 7-14% of that of bacteroidetes, 6-9% of that of the phylum of the bacteria of the genus of the bacteria of the genus of the bacteria of the genus zymomonas, and 4-7% of that of the phylum of the genus of the bacteria of the genus acidobacter.
In practical application, when the water quality of the polyurethane wastewater is pH 6.9-7.7, COD is 2270-4520mg/L, formaldehyde content is 23-31mg/L, and acetone content is 12-19mg/L, the flow rate in the suspended filler biochemical pool 2 is 1.7-1.9m for carrying out the year, the hydraulic retention time is 17-27h, the volume load is 3.2-3.6kg/(m for carrying out the year), and the dissolved oxygen is 3.4-4.2 mg/L.
Under the combined action of the activated sludge in the biochemical pool of the suspended filler biochemical pool 2 and the sludge in the hydrophilic suspended filler 3, the water quality parameters of the polyurethane wastewater become after treatment: pH =7.0-7.5, COD 321-567mg/L, formaldehyde content of 1.2-3.1mg/L, and acetone content of 0.6-1.2 mg/L.
The three-dimensional electrooxidation device 5 comprises an electrolytic bath for containing waste water, a plurality of modified stainless steel electrodes 6 are arranged at the upper part of the electrolytic bath, and modified active coke fillers 7 are filled in the electrolytic bath. In general, no filler is arranged in the three-dimensional electro-oxidation device 5, but the invention combines electro-oxidation degradation and filler adsorption, so that the adsorption and fixation of organic pollutants can be enhanced on one hand, and the retention time of the organic pollutants in an electrolytic bath can be prolonged on the other hand, thereby being more thoroughly degraded by electro-oxidation.
In the three-dimensional electro-oxidation device 5, active-OH is generated through electrode reaction of the modified stainless steel electrode 6 and is used for attacking organic pollutants and mineralizing organic matters. In order to improve the oxygen evolution potential of a common stainless steel electrode and improve the electrolysis efficiency, the existing stainless steel electrode of the three-dimensional electro-oxidation device 5 is modified by the following method:
firstly, heating industrial-grade ferric trichloride to 215 ℃ at the temperature of 6-9 ℃/min, and preserving heat in a muffle furnace for 1.5h for natural cooling to obtain an oxy ferric chloride block. Preparing 1.5-2.7mol/L manganese nitrate solution and 0.4-1.2mol/L ruthenium chloride solution, and then mixing according to the volume ratio of 1:1 to form ruthenium-manganese mixed solution. ③ grinding the ferric oxychloride block into powder, adding 500mg of 350-fold ferric oxychloride powder into each liter of the ruthenium-manganese mixed solution, and carrying out ultrasonic and magnetic stirring for 35-45min to form the iron-ruthenium-manganese mixed solution. And fourthly, polishing the stainless steel electrode plate to remove surface impurities and organic substances, thus obtaining a smooth electrode surface. Dipping the stainless steel electrode in the iron-ruthenium-manganese mixed solution for 30-50min, then placing the stainless steel electrode in a muffle furnace, firstly heating the muffle furnace to 145 ℃ at the speed of 5-10 ℃/min, continuing for 0.5-1h, then heating to 420 ℃ at the speed of 400 ℃ at the speed of 6-10 ℃/min, keeping the temperature for 1-2h, and cooling. And cooling to room temperature, and repeating the dipping-sintering for 4-6 times according to the mode to prepare the ruthenium-manganese modified stainless steel electrode. Fig. 2 shows the modified stainless steel electrode 6. Generally, the oxygen evolution potential of the electrode before the modification of the stainless steel electrode is about 0.9V (relative to the oxygen evolution potential value of a silver/silver chloride standard hydrogen electrode), and the oxygen evolution potential of the modified stainless steel electrode 6 is about 1.35V (relative to the oxygen evolution potential value of a silver/silver chloride standard hydrogen electrode). Through modification, the oxygen evolution potential of the electrode is improved, more hydroxyl free radicals are generated, and the oxidation of organic matters is facilitated. In order to improve the specific surface area of the filler in the three-dimensional electrooxidation device 5, the invention modifies the conventional active coke filler to obtain a modified active coke filler 7. The modification method can be referred to as follows:
firstly, selecting cylindrical active coke with the diameter of 2-4 mm; preparing 123-235mg/L ferric trichloride solution and 35-55mg/L manganese sulfate solution, and mixing according to the volume ratio of 3-4:1 to form iron-manganese mixed solution; immersing the active coke in the iron-manganese mixed solution for 12-16h, taking out, putting into a muffle furnace, firstly heating the muffle furnace to 400 ℃ in oxygen-free/oxygen-deficient conditions at a speed of 8-10 ℃/min, keeping the temperature for 2.5-3.5h, cooling, and preparing the modified active coke filler with the specific surface area of 345 + 411 m/g. Wherein, the modified active coke filler 7 is filled in the electrolytic tank by 25-35% in volume, and all the modified stainless steel electrodes 6 account for 15-25% of the electrolytic tank in volume.
In the operation process, the hydraulic retention time in the three-dimensional electrooxidation device 5 is 35-50min, the distance between the electrodes is 1-2cm, the current density is 2.7-3.2A/square meter, the oxygen evolution potential of the modified stainless steel electrode 6 is 1.25-1.45V (relative to the oxygen evolution potential value of a silver/silver chloride standard hydrogen electrode), and the specific surface area of the modified active coke filler 7 is 345 + 411 m/g. In the three-dimensional electrooxidation device 5, the polyurethane wastewater is coupled with the electrochemical oxidation of the modified stainless steel electrode 6 through the enhanced adsorption of the modified active coke filler 7, so that after the treatment of the three-dimensional electrooxidation device 5, the water quality parameters of the polyurethane wastewater become: pH =7.0-7.5, COD 67-89mg/L, formaldehyde content 0.2-0.8mg/L, acetone content 0.1-0.3 mg/L.
Finally, the water enters a filler adsorption tower 9 for reinforced adsorption and purification treatment. The filler adsorption tower 9 is a cylindrical tower body, and the height and diameter ratio of the tower body is 4-6: 1, 80-85% of its internal volume is filled with the modified diatomaceous earth filler 10.
The modified diatomite filler 10 is modified by taking diatomite as a raw material so as to improve the adsorption capacity and the adsorption stability of the diatomite. The modified diatomaceous earth filler 10 may be prepared as follows:
firstly, screening diatomite with the particle size of 0.5-0.8mm, screening biochar with the particle size of 1-2mm, mixing the diatomite and the biochar according to the volume ratio of 6-9:1, and then mechanically stirring for 10-15min to form a diatomite-biochar mixture;
preparing 345 and 521mg/L aluminum sulfate solution, and adding 4-6g of diatomite-charcoal mixture into each liter of aluminum sulfate solution;
thirdly, the mixed solution is radiated for 15-20min under the condition of the microwave power of 700-1000W to strengthen the mixing effect of the solution, then the solution is stirred for 25-45min and filtered to prepare the modified diatomite filler, and the specific surface area is 358-405 square meters/kg. In the stable operation process, the retention time of the polyurethane wastewater in the filler adsorption tower 9 is 35-40 min.
After being treated by the filler adsorption tower 9, the water quality parameters of the polyurethane wastewater become as follows: pH =7.0-7.4, COD is 16-28mg/L, formaldehyde content is 0.01-0.03mg/L, and acetone content is 0.01-0.02 mg/L.
At this time, through calculation, compared with the raw water of the polyurethane wastewater, the COD value is reduced by more than 99.3%, the formaldehyde content is reduced by more than 99.95%, and the acetone content is reduced by more than 99.89%.
The effluent water from the filler adsorption tower 9 is discharged or merged into a general wastewater treatment system through a drainage pump 11.
The following description is given in conjunction with specific embodiments of the present invention.
Example 1
Polyurethane wastewater treatment was carried out using the system shown in FIG. 1. The raw water quality characteristics of the polyurethane wastewater are as follows: the pH value is 7.2, the COD is 3120mg/L, the formaldehyde content is 24mg/L, and the acetone content is 14 mg/L.
The filling amount of the hydrophilic suspended filler 3 (namely the modified polyethylene filler) in the biochemical pool 2 of the suspended filler is 34 percent. The flow rate of the polyurethane wastewater in the suspended filler biochemical pool 2 is 1.7 m/h, the hydraulic retention time is 18h, the volumetric load is 3.3kg/(m · d), and the dissolved oxygen is 3.5 mg/L. The modified polyethylene filler 3 is cylindrical, has the diameter of 20mm, the height of 8mm and the density of 0.96g/cm3Porosity is 80%, specific surface area 820 m.
In the stable operation process, the relative abundance of the microbial flora in the activated sludge in the suspended filler biochemical pool 2 is 37% of proteobacteria, 6% of bacteroidetes, 5% of the relative abundance of the pseudomonas and 5% of the relative abundance of the acidobacter. Inside the hydrophilic suspended filler 3, the relative abundance of the phylum Proteobacteria, the relative abundance of the phylum Bacteroides, the relative abundance of the phylum Buymomonas and the relative abundance of the phylum Acidobacterium are 43%, 8% and 6%, respectively.
After being treated by the suspended filler biochemical pool 2, the pH value of the polyurethane wastewater is 7.2, the COD is 421mg/L, the formaldehyde content is 1.8mg/L, and the acetone content is 0.9 mg/L.
Then, the polyurethane wastewater enters the three-dimensional electrooxidation device 5. In the stable operation process, the hydraulic retention time is 38 min. The modified stainless steel electrodes 6 are provided with a plurality of electrodes, the total volume of the modified stainless steel electrodes accounts for 19 percent of the total volume of the electrolytic bath of the three-dimensional electrooxidation device 5, the distance between every two adjacent electrodes is 1cm, and the current density is 2.9A/square meter. The modified active coke filler 7 accounts for 25% of the volume of the electrolytic bath of the three-dimensional electro-oxidation device 5. The specific surface area of the modified active coke filler 7 is 355 square meters per gram.
The preparation method of the modified stainless steel electrode 6 comprises the following steps: 1) heating industrial-grade ferric trichloride to 215 ℃ at the temperature of 6 ℃/min, and preserving the heat in a muffle furnace for 1.5h for naturally cooling to obtain the ferric oxychloride block. 2) Preparing a manganese nitrate solution of 1.8mol/L and a ruthenium chloride solution of 0.7mol/L, and then mixing according to the volume ratio of 1:1 to form a ruthenium-manganese mixed solution; 3) grinding the iron oxychloride block into powder, adding 370mg of iron oxychloride powder into each liter of ruthenium-manganese mixed solution, and carrying out ultrasonic and magnetic stirring for 35min to form iron-ruthenium-manganese mixed solution; 4) polishing the stainless steel electrode plate with powder to remove impurities and organic substances on the surface of the electrode and obtain a smooth electrode surface. 5) Soaking a stainless steel electrode in the ruthenium-manganese mixed solution for 30min, then placing the stainless steel electrode in a muffle furnace, firstly heating the muffle furnace to 130 ℃ at the speed of 5 ℃/min, continuing for 0.5h, then heating to 410 ℃ at the speed of 8 ℃/min, keeping the temperature for 1h, and cooling. After cooling to room temperature, dipping-sintering was repeated 4 times to prepare a successfully modified stainless steel electrode 6. The modified stainless steel electrode 6 has an oxygen evolution potential of 1.35V (relative to the oxygen evolution potential of a silver/silver chloride standard hydrogen electrode).
The preparation method of the modified active coke filler 7 comprises the following steps: 1) selecting cylindrical active coke with the diameter of 2 mm; 2) preparing 145mg/L ferric trichloride solution and 35mg/L manganese sulfate solution, and then mixing according to the volume ratio of 3:1 to form iron-manganese mixed solution; 3) and (3) putting the active coke in the iron-manganese mixed solution for 12h, taking out, putting into a muffle furnace, heating the muffle furnace to 410 ℃ at the speed of 8 ℃/min, keeping the temperature for 3h under the anoxic condition, and cooling to obtain the modified active coke filler, wherein the specific surface area is 355 square meters per gram.
After being treated by the three-dimensional electrooxidation device 5, the pH value of the polyurethane wastewater is 7.2, the COD is 73mg/L, the formaldehyde content is 0.3mg/L, and the acetone content is 0.1 mg/L.
And finally, the polyurethane wastewater enters a filler adsorption tower 9. The height and diameter ratio of the tower body of the filler adsorption tower 9 is 5: 1, wherein the modified diatomite filler 10 has a filling volume ratio of 80%. The specific surface area of the modified diatomite filler 10 is 367 square meters per kg, and the hydraulic retention time in stable operation is 35 min.
The preparation method of the modified diatomite filler 10 comprises the following steps: 1) sieving diatomite with the particle size of 0.5mm, sieving biochar with the particle size of 1mm, mixing the diatomite and the biochar according to the volume ratio of 6:1, and then mechanically stirring for 10min to form a diatomite-biochar mixture. 2) 351mg/L of aluminum sulfate solution is prepared, and 4g of diatomite-charcoal mixture is placed in each liter of aluminum sulfate solution. 3) The mixed solution is irradiated for 15min under the condition of microwave power of 700W, and then stirred for 25 min. And filtering to obtain the modified diatomite filler.
The pH of the polyurethane wastewater discharged from the filler adsorption tower 9 is 7.2, the COD is 21mg/L, the formaldehyde content is 0.01mg/L, and the acetone content is 0.01 mg/L. COD is reduced by 99.32%, formaldehyde concentration is reduced by 99.96%, and acetone concentration is reduced by 99.93%. At the moment, the water quality completely meets the discharge standard of organic wastewater containing formaldehyde, acetone and the like, and can be directly discharged.
Example 2
Polyurethane wastewater treatment was carried out using the system shown in FIG. 1. The raw water quality characteristics of the polyurethane wastewater are as follows: the pH was 7.6, the COD was 4110mg/L, the formaldehyde content was 30mg/L, and the acetone content was 17 mg/L. The filling amount of the hydrophilic suspended filler 3 (namely the modified polyethylene filler) in the biochemical pool 2 of the suspended filler is 36 percent. The flow rate of the polyurethane wastewater in the suspended filler biochemical pool 2 is 1.9 m/h, the hydraulic retention time is 25h, the volume load is 3.5kg/(m year. d), and the dissolved oxygen is 4.2 mg/L. The modified polyethylene filler 3 is a cylinderShape, diameter of 20mm, height of 8mm, and density of 0.96g/cm3Porosity is 80%, specific surface area 820 m.
In the stable operation process, the relative abundance of the microbial flora in the activated sludge in the suspended filler biochemical pool 2 is 41 percent of proteobacteria, 8 percent of bacteroidetes, 6 percent of the relative abundance of the pseudomonas and 4 percent of the relative abundance of the acidobacter. And because the hydrophilic suspended filler 3 has better affinity with microorganisms, the relative abundance of proteobacteria is 51%, the relative abundance of bacteroidetes is 11%, the relative abundance of pseudomonas is 8% and the relative abundance of acidobacter is 6% in the hydrophilic suspended filler 3.
After being treated by the suspended filler biochemical pool 2, the pH value of the polyurethane wastewater is 7.5, the COD is 511mg/L, the formaldehyde content is 2.8mg/L, and the acetone content is 1.1 mg/L.
Then, the polyurethane wastewater enters the three-dimensional electrooxidation device 5. In the stable operation process, the hydraulic retention time is 45 min. The modified stainless steel electrodes 6 are provided with a plurality of electrodes, the total volume of the modified stainless steel electrodes accounts for 25 percent of the total volume of the three-dimensional electrooxidation device 5, the distance between every two adjacent electrodes is 2cm, and the current density is 3.2A/square meter. The modified active coke filler 7 accounts for 35% of the volume of the electrolytic bath of the three-dimensional electro-oxidation device 5. The specific surface area of the modified active coke filler 7 is 401 square meters per gram.
The preparation method of the modified stainless steel electrode 6 comprises the following steps: 1) heating industrial-grade ferric trichloride to 215 ℃ at the temperature of 9 ℃/min, and preserving the heat in a muffle furnace for 1.5h for naturally cooling to obtain the ferric oxychloride block. 2) Preparing a manganese nitrate solution of 2.6mol/L and a ruthenium chloride solution of 1.1mol/L, and then mixing according to the volume ratio of 1:1 to form a ruthenium-manganese mixed solution; 3) grinding the iron oxychloride block into powder, adding 500mg of iron oxychloride powder into each liter of ruthenium-manganese mixed solution, and performing ultrasonic and magnetic stirring for 45min to form iron-ruthenium-manganese mixed solution; 4) polishing the stainless steel electrode plate with powder to remove impurities and organic substances on the surface of the electrode and obtain a smooth electrode surface. 5) Soaking a stainless steel electrode in the ruthenium-manganese mixed solution for 50min, then placing the stainless steel electrode in a muffle furnace, firstly heating the muffle furnace to 139 ℃ at 8 ℃/min for 1h, then heating to 410 ℃ at 8 ℃/min, keeping the temperature for 1h, and cooling. After cooling to room temperature, dipping-sintering was repeated 6 times to prepare a successfully modified stainless steel electrode 6. The modified stainless steel electrode 6 has an oxygen evolution potential of 1.37V (relative to the oxygen evolution potential of a silver/silver chloride standard hydrogen electrode).
The preparation method of the modified active coke filler 7 comprises the following steps: 1) selecting cylindrical active coke with the diameter of 4 mm; 2) preparing 235mg/L ferric trichloride solution and 51mg/L manganese sulfate solution, and then mixing according to the volume ratio of 4:1 to form iron-manganese mixed solution; 3) and (3) putting the active coke in the iron-manganese mixed solution for 16h, taking out, putting into a muffle furnace, heating the muffle furnace to 410 ℃ at a speed of 10 ℃/min, keeping the temperature constant for 3h under an anoxic condition, and cooling to obtain the modified active coke filler, wherein the specific surface area is 401 square meters per gram.
After being treated by the three-dimensional electrooxidation device 5, the pH value of the polyurethane wastewater is 7.2, the COD is 81mg/L, the formaldehyde content is 0.7mg/L, and the acetone content is 0.3 mg/L.
And finally, the polyurethane wastewater enters a filler adsorption tower 9. The height and diameter ratio of the tower body of the filler adsorption tower 9 is 5: 1, wherein the modified diatomite filler 10 has a filling volume ratio of 85%. The specific surface area of the modified diatomite filler 10 is 399m2And/kg, the hydraulic retention time in stable operation is 40 min.
The preparation method of the modified diatomite filler 10 comprises the following steps: 1) sieving diatomite with the particle size of 0.8mm, sieving biochar with the particle size of 2mm, mixing the diatomite and the biochar according to the volume ratio of 9:1, and then mechanically stirring for 15min to form a diatomite-biochar mixture. 2) 521mg/L of aluminum sulfate solution is prepared, and 6g of diatomite-charcoal mixture is placed in each liter of aluminum sulfate solution. 3) The mixed solution is irradiated for 20min under the condition of microwave power of 700W, and then stirred for 45 min. After filtration, the modified diatomite filler 10 with the specific surface area of 399m is prepared2/kg。
The pH of the polyurethane wastewater discharged from the filler adsorption tower 9 is 7.4, the COD is 28mg/L, the formaldehyde content is 0.03mg/L, and the acetone content is 0.02 mg/L. COD is reduced by 99.32%, formaldehyde concentration is reduced by 99.9%, and acetone concentration is reduced by 99.89%. At the moment, the water quality completely meets the discharge standard of organic wastewater containing formaldehyde, acetone and the like, and can be directly discharged.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (3)

1. An advanced treatment system for polyurethane wastewater is characterized in that a suspended filler biochemical pool, a three-dimensional electrooxidation device and a filler adsorption tower are arranged along the water flow direction;
the water quality of the polyurethane wastewater raw water is characterized in that: the pH value is 6.9-7.7, the COD is 2270-4520mg/L, the formaldehyde content is 23-31mg/L, and the acetone content is 12-19 mg/L; the effluent quality of the filler adsorption tower is characterized in that: pH is 7.0-7.4, COD is 16-28mg/L, formaldehyde content is 0.01-0.03mg/L, and acetone content is 0.01-0.02 mg/L;
the biochemical pool of the suspended filler comprises a biochemical pool and hydrophilic suspended filler filled in the biochemical pool; the density of the hydrophilic suspended filler is 0.92-0.99g/cm3The porosity is 75-85%, the specific surface area is 800-3The filling volume percentage is 33-37%; the microbial flora in the activated sludge and the hydrophilic suspended filler in the biochemical pool comprises proteobacteria, bacteroidetes, pseudomonas and acidibacterium;
the relative abundance of the microbial flora in the activated sludge and the hydrophilic suspended filler in the biochemical pool is 34-45% of proteobacteria, 5-9% of bacteroidetes, 4-7% of pseudomonas and 3-6% of acidobacteroides; the microbial flora in the hydrophilic suspended filler is the same as that in the activated sludge, and the microbial flora in the hydrophilic suspended filler is 42-58% of Proteobacteria relative abundance, 7-14% of Bacteroides relative abundance, 6-9% of Buymomonas relative abundance and 4-7% of Acidobacterium relative abundance;
the three-dimensional electrooxidation device comprises an electrolytic bath, wherein a plurality of modified stainless steel electrodes are arranged at the upper part of the electrolytic bath, and modified fillers are filled in the electrolytic bath; the oxygen evolution potential of the modified stainless steel electrode relative to a silver/silver chloride standard hydrogen electrode is 1.25-1.45V; the modified filler is modified active coke filler with specific surface area of 345 plus one square meter per gram (411 square meters per gram), and the filling volume percentage is 25-35%; the total volume of the modified stainless steel electrodes accounts for 15-25% of the volume of the electrolytic cell, and the distance between adjacent electrodes is 1-2 cm;
the modified stainless steel electrode is a ruthenium manganese oxide modified stainless steel electrode and the preparation method comprises the following steps:
(1) mixing 1.5-2.7mol/L manganese nitrate solution and 0.4-1.2mol/L ruthenium chloride solution to obtain ruthenium-manganese mixed solution;
(2) adding 350-500mg of oxy-ferric chloride powder into each liter of ruthenium-manganese mixed solution, and carrying out ultrasonic and magnetic stirring for 35-45min to form iron-ruthenium-manganese mixed solution;
(3) polishing the surface of the stainless steel electrode, and removing surface impurities and organic substances to obtain the stainless steel electrode with a smooth surface;
(4) dipping the stainless steel electrode in the iron-ruthenium-manganese mixed solution obtained in the step (3) for 30-50min, then preserving the heat for 0.5-1h at the temperature of 130-; performing the step for 4-6 times to prepare the ruthenium manganese oxide modified stainless steel electrode;
the modified active coke filler is a ferro-manganese modified active coke filler; the preparation method comprises the following steps:
(1) preparing a 123-235mg/L ferric trichloride solution and a 35-55mg/L manganese sulfate solution, and mixing the two solutions according to a volume ratio of 3-4:1 to form a ferro-manganese mixed solution;
(2) taking cylindrical active coke with the diameter of 2-4mm, immersing the active coke in the ferro-manganese mixed solution for 12-16h, taking out the active coke, heating the active coke to 400-420 ℃ at a speed of 8-10 ℃/min, preserving the heat for 2.5-3.5h in an anaerobic/anoxic environment, and cooling the active coke to obtain the ferro-manganese modified active coke filler; the filler adsorption tower comprises a tower body and modified diatomite filler filled in the tower body, wherein the height-to-diameter ratio of the tower body is 4-6: 1, the filling volume percentage is 80-85%; the specific surface area of the modified diatomite filler is 358-405 square meters per kg; the modified diatomite filler is aluminum sulfate activated biochar-diatomite filler, and the preparation method comprises the following steps:
(1) sieving diatomite with a particle size of 0.5-0.8mm, sieving biochar with a particle size of 1-2mm, mixing the diatomite and the biochar according to a volume ratio of 6-9:1, and mechanically stirring for 10-15min to form a diatomite-biochar mixture;
(2) 345 and 521mg/L of aluminum sulfate solution are prepared, and 4-6g of diatomite-charcoal mixture is added into each liter of aluminum sulfate solution;
(3) radiating the mixed solution for 15-20min under the condition of microwave power of 700-.
2. The advanced polyurethane wastewater treatment system as claimed in claim 1, wherein the hydrophilic suspended filler is a modified polyethylene filler, and oxygen-containing polar groups and hydrophilic polymers are added in the filler production process to improve the affinity of the modified polyethylene filler for biological bacteria.
3. An advanced treatment method of polyurethane wastewater, which employs the advanced treatment system of polyurethane wastewater of claim 1 or 2, comprising three treatment processes:
firstly, raw water of polyurethane wastewater is conveyed into a suspended filler biochemical pool, and the COD (chemical oxygen demand), formaldehyde and acetone contents of the polyurethane wastewater are reduced under the combined action of activated sludge in the suspended filler biochemical pool and active biological bacteria in hydrophilic suspended fillers;
the flow velocity of the raw water of the polyurethane wastewater in the suspended filler biochemical pool is 1.7-1.9m3The hydraulic retention time is 17-27h, and the volume load is 3.2-3.6 kg/(m)3D) dissolved oxygen of 3.4-4.2 mg/L;
then, the effluent of the suspended filler biochemical pool enters a three-dimensional electro-oxidation device, and the COD, formaldehyde and acetone contents of the polyurethane wastewater are further reduced by coupling the enhanced adsorption effect of the modified active coke filler in the electrolytic bath through the electrolytic reaction of the three-dimensional electro-oxidation device;
wherein, the retention time of the water power in the three-dimensional electro-oxidation device is 35-50min, and the current density is 2.7-3.2A/square meter;
finally, the effluent of the three-dimensional electrooxidation device enters a filler adsorption tower, and the hydraulic retention time is 35-60 min; the COD, formaldehyde and acetone contents of the polyurethane wastewater are reduced again through the adsorption effect of the modified diatomite filler; the effluent of the filler adsorption tower is discharged or converged into a general wastewater treatment system.
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