CN104261628A - Method for treating degradation-resistant organic wastewater by membrane potential biological coupling process - Google Patents

Abstract

The present invention relates to a method for treating refractory organic wastewater by a membrane electrobiological coupling process. The feature of the present invention is that the membrane electrobiological coupling process is divided into anaerobic and aerobic areas, and the cathode plate is placed in the anaerobic area. Both the filter membrane and the anode plate are placed in the aerobic zone, the average pore size of the membrane is between 0.1 and 0.4 μm, and the membrane filter adopts negative pressure suction to discharge water. The invention is developed by using electric-assisted enhanced microbial reduction and oxidative degradation of refractory biodegradable wastewater and coupled with membrane filtration technology, which realizes the complete separation of anaerobic microorganisms and aerobic microorganisms, and uses membranes to filter water, simplifying the process flow. The method can remove more than 90% of COD _Cr and more than 95% of chroma in refractory organic wastewater. The enhanced degradation of electrobiology makes the sewage treatment effect better, and the membrane fouling is well controlled. Membrane effluent improves the efficiency of solid-liquid separation, and the effluent quality is stable.

Description

A method for the treatment of refractory organic wastewater by a membrane electrobiological coupling process

technical field

The invention relates to a method for treating refractory organic wastewater by a membrane-electrobiological coupling process. The method is mainly developed by using electric-assisted microorganisms (electrobiology) to strengthen the reduction and oxidative degradation process of refractory organic wastewater and coupling membrane filtration technology. In the field of environmental protection,

Background technique

With the development of social industry, the treatment of refractory organic matter in the water environment is a difficult point in environmental governance. In view of the increasing diversification of industrial wastewater containing refractory organic matter and the increasing difficulty of biochemical treatment, especially medical wastewater, printing and dyeing wastewater, Chemical and fuel wastewater, etc. The wastewater has complex components, large chroma, and high biological toxicity. The effect of conventional biological treatment is poor, and the content of suspended solids in the effluent is high. As a means to strengthen the treatment of microorganisms, electrical assistance, especially the electro-assisted cathode to provide electron donors required for microbial reductive degradation, can greatly improve the reductive degradation efficiency of organisms. In addition, electrical assistance, as a biostimulant, causes organisms to produce a series of electric field biochemical effects, which further improves the degradation efficiency of microorganisms. The core of the electrobiological system is to form a multiphase coupling process of electrical assistance and microbial metabolism to improve the treatment efficiency of refractory biodegradable organic wastewater.

Membrane filtration is a high-efficiency separation process widely used in the field of water treatment, such as MBR sewage treatment process, CMF process for sewage reuse, etc. Refractory organic wastewater affects the sludge-water separation of sludge microorganisms due to its water quality characteristics, resulting in a high content of suspended solids in the effluent after biological treatment, which affects both effluent water quality and the enrichment of sludge microorganisms in the biodegradation system. Therefore, the coupling of electrobiology and membrane filtration to form a membrane electrobiology coupling process for the treatment of refractory organic wastewater has broad application prospects.

Contents of the invention

The purpose of the invention is to combine electrobiology and membrane filtration to improve synergistically enhanced degradation efficiency of membrane electrobiology process in respect of refractory organic pollutants. A new method for efficiently and stably degrading refractory organic wastewater by using microorganisms under electrocatalysis and filtering the water through membranes is provided.

The present invention is characterized in that: the electrobiological system is divided into anaerobic and aerobic areas, the cathode plate is placed in the anaerobic area, and the cathode plate adopts a palladium plate, a palladium plated plate or a The graphite plate is only stirred without aeration; the anode plate is placed in the aerobic area, and the filter membrane is also placed in the aerobic area, where aeration is used to supply oxygen and purge the membrane surface. The anaerobic zone of the coupling process is in an anaerobic state. In the case of electric assist electron supply, anaerobic microorganisms use the electrons provided by electric assist to reduce and degrade organic pollutants, and then the wastewater overflows into the aerobic zone, where the After biological aerobic treatment and anodic oxidation treatment, the water is filtered through negative pressure suction membrane. The outer diameter of the filter membrane is between 5.0-15 mm, the inner diameter is between 2-12 mm, and the average pore diameter of the membrane is between 0.1-0.4 μm. The electrobiological system can give full play to the strengthening effect of microorganisms and electric assistance, and microorganisms can maintain their respective optimal degradation environments under anaerobic and aerobic conditions. The voltage of the electric auxiliary electrode is 0.2-3V, the total hydraulic retention time is 20-50h, and the hydraulic retention time ratio of the anaerobic and aerobic zones of the coupling process is 1:1-5:1. The stirring intensity in the anaerobic zone is 2-8w/m ³ , and the gas-water ratio of aeration in the aerobic zone is 5-10:1.

The invention has the advantages of fully exerting the coupling advantages of electrobiology and membrane filtration, and simplifying the technological process. The method can remove more than 90% of COD _Cr and more than 95% of chroma in refractory organic wastewater, the electrobiology improves the sewage treatment effect, and the membrane fouling is well controlled. Membrane effluent improves the efficiency of solid-liquid separation, and the effluent quality is stable.

Description of drawings

Figure 1: Schematic diagram of the membrane electrobiological coupling process for the treatment of refractory organic wastewater

1. Water inlet 2. Stirrer 3. Cathode plate 4. Anaerobic zone 5. Anaerobic mixture overflow 6. Anaerobic sedimentation zone 7. Anaerobic effluent

8. Anode plate 9. Membrane suction water 10. Anode area 11. Vacuum pump 12. Aeration system 13. DC power supply

Detailed ways

Example 1:

Coking chemical organic wastewater is treated by membrane electrobiological coupling process, and the treated water volume is 15m ³ /h. The organic waste water contains phenol, cyanide, chlorophenol, coal tar and other organic matter, and the COD _Cr content is between 1500 and 3000 mg/L. The residence time of coking chemical organic wastewater in the reactor is 20h, the hydraulic retention time in the anaerobic zone and the aerobic zone are both 10h, the microbial concentration in the anaerobic zone is between 3000-5000mg/L, and the microbial concentration in the aerobic zone is 2000 ~4000mg/L. The stirring power in the anaerobic zone is 150W, the gas-water ratio of aeration in the aerobic zone is 8:1, the cathode plate is made of titanium-based palladium-plated mesh flat plate, the anode is made of graphite plate, and the voltage applied by the DC power supply is 1.2V.

After commissioning and stable operation, the water quality of membrane effluent is as follows: phenol < 0.5mg/L, cyanide < 0.2mg/L, COD < 90mg/L. During commissioning and nearly one year of operation, the membrane flux has almost no attenuation, and the sewage treatment effect Well, membrane fouling is well under control. The invention provides a new method and idea for the efficient degradation of refractory organic wastewater.

Example 2:

The sewage from the printing and dyeing wastewater treatment station contains disperse blue ionic dyes, the chroma is 300-500 times, the COD _Cr is 300-500mg/L, the SS is 130mg/L, the treated water volume is 200m ³ /d, and the BOD/COD is 0.25. Biochemically poor. The original treatment process adopts the process of coagulation sedimentation-microbial anaerobic degradation-microbial aerobic degradation. The concentration of COD _Cr in the effluent is 100-150mg/L, and the chroma of the effluent is high, which does not meet the environmental protection discharge requirements. In order to improve the removal effect, the electric biofilm filtration coupling process of the invention is used for transformation. A drum-shaped mesh titanium-based palladium-plated cathode plate is installed in the anaerobic reactor, and a mesh steel plate is installed as an anode in the aerobic tank. The regulated DC voltage provides a voltage of 1.5V. After the installation of the pole plate was completed, after a month of operation and commissioning, the normal operation began. The water quality test was carried out under the condition that the treated wastewater flow rate, water quality and hydraulic retention time were not changed. The detected water quality was: effluent COD _Cr concentration At 30-50 mg/L, the removal rate is above 92%, and the chroma is 10-15 times. After the transformation, the wastewater treatment efficiency increased by nearly 30% compared with the original process, while the treatment operation cost only increased by 5%, the membrane fouling was well controlled, and the membrane flux remained basically stable. It meets the needs of environmental protection and transformation requirements, and runs stably.

Draw from embodiment 1 and embodiment 2: adopt a kind of method of membrane electrobiological coupling process of the present invention to process refractory organic waste water, the processing effect to refractory biodegradable waste water is stable, compares traditional microbial method on processing effect. Larger improvement, and the improvement of treatment efficiency also makes membrane fouling better controlled. This invention can upgrade and transform the existing biological treatment process to improve treatment efficiency.

A method for treating refractory organic wastewater by a membrane electrobiological coupling process proposed by the present invention has been described through the examples, and those skilled in the art can clearly understand the content described herein without departing from the content, spirit and scope of the present invention Changes or appropriate changes and combinations are made to realize the present invention. In particular, it should be pointed out that all similar substitutions and modifications would be obvious to those skilled in the art, and they are all considered to be included in the spirit, scope and content of the present invention.

Claims (5)

1. the method for a film electricity biological coupling art breading organic wastewater with difficult degradation thereby, it is characterized in that: film electricity biological coupling technique is divided into anaerobic and aerobic two regions, negative plate is placed in anaerobic zone, negative plate adopts palladium pole plate, plating palladium pole plate or the graphite electrode plate with the gentle slow release electric function of accumulate, this region is only stirred, not aeration, and filtering membrane and positive plate are all placed in aerobic region, film adopts negative pressure-pumping water outlet, and this aerobic zone is carried out aeration oxygen supply and purged film surface; The power acquisition D.C. regulated power supply that electricity is auxiliary, the anaerobic zone of film electricity biological coupling technique is in the state of anaerobism, anaerobion utilizes the electron reduction degradable organic pollutant of electric assisted Extraction confession, then waste water outflow enters aerobic zone, after biology aerobic process and anodic oxidation treatment are carried out in aerobic zone, through negative pressure-pumping film filtration effluent; The enhancing degradation of electricity biology makes good sewage processing effect, and fouling membrane obtains good control; Film water outlet improves the efficiency of solid-liquid separation, stable effluent quality; The external diameter of filtering membrane is between 5.0 ~ 15mm, and internal diameter is between 2 ~ 12mm, and the mean pore size of film is between 0.1 ~ 0.4 μm; Electricity living things system can give full play to the auxiliary strengthening effect of microorganism and electricity, and microorganism can keep respective the best degraded environment under anaerobism or aerobic condition; The voltage of electricity supporting electrode is 0.2 ~ 3V, and total hrt is at 20 ~ 50h, and the anaerobism of reactor is 1: 1 ~ 5: 1 with the hydraulic detention time ratio in aerobic region; The stirring intensity of anaerobic zone is 2 ~ 8w/m ³, the gas-water ratio of aerobic region aeration is 5 ~ 10: 1.

2. the method for a kind of film electricity biological coupling art breading organic wastewater with difficult degradation thereby as described in claim 1, is characterized in that in the anaerobism that the positive plate that electricity is auxiliary and negative plate are separately positioned on film electricity biological coupling technique and aerobic two different zones; Reactor total hrt is at 10 ~ 20h, and the anaerobism of reactor is 1: 1 ~ 5: 1 with the hydraulic detention time ratio in aerobic region; The stirring intensity of anaerobic zone is at 2 ~ 8w/m ³, the gas-water ratio of the aeration in aerobic region is 5 ~ 10: 1.

3. the method for a kind of film electricity biological coupling art breading organic wastewater with difficult degradation thereby as described in claim 1, it is characterized in that first organic wastewater with difficult degradation thereby enters film electricity biological coupling technique anaerobic zone after micro-reduction degraded, enter aerobic region again to degrade, finally by negative pressure-pumping film filtration effluent.

4. the method for a kind of film electricity biological coupling art breading organic wastewater with difficult degradation thereby as described in claim 1, it is characterized in that anaerobion is separated completely with aerobic microbiological, negative plate is placed on anaerobic zone, and positive plate and filtering membrane are all placed on aerobic zone, and aerobic zone aeration oxygen supply also purges film surface.

5. the method for a kind of film electricity biological coupling art breading organic wastewater with difficult degradation thereby as described in claim 1, is characterized in that the voltage between anode and cathode is: 0.2 ~ 3V.