WO2012126316A2

WO2012126316A2 - Sewage recycling device based on electrolysis and mbr technologies and method thereof

Info

Publication number: WO2012126316A2
Application number: PCT/CN2012/071912
Authority: WO
Inventors: 张世文
Original assignee: 波鹰(厦门)科技有限公司
Priority date: 2011-03-24
Filing date: 2012-03-05
Publication date: 2012-09-27
Also published as: WO2012126316A3; CN102120678A; CN102120678B

Abstract

A sewage recycling device based on electrolysis and MBR technologies and a method thereof relate to sewage treatment and recycling. The sewage recycling device is provided with an electrolysis system and an MBR system. The electrolysis system is provided with a stop valve, a water supply pump and an electrolysis machine. The MBR system is provided with a grating, an MBR reaction tank, an MBR assembly, a blower, an aerator, a sewage pump, an effluent pump and a regenerated water storage tank. The in-depth treated sewage, after biochemical treatment, of a secondary sedimentation tank is extracted by a water pump and sent in the electrolysis machine for electrolysis, then passes through the grating to enter the MBR system to remove solid impurities incurred by the electrolysis, plankton, bacteria and colloid and obtain purified sewage; and the purified sewage treated by the electrolysis system flows into the MBR system through a pipe to undergo solid-liquid separation, thus the recycling of sewage is completed. The in-depth treatment and recycling of sewage can be realized, the sewage discharge can be reduced and the utilization efficiency of water can be increased.

Description

Sewage recycling device based on electrolysis and MBR technology and method thereof

Technical field

The invention relates to a sewage treatment and recycling cycle utilization, in particular to an electrolysis technology and an MBR (membrane bioreactor) technology combined with advanced treatment of wastewater recycling and recycling methods.

Background technique

Water resources and environmental pollution are increasingly being valued by human society. On the one hand, water consumption is increasing, water resources are increasingly scarce, and on the other hand, sewage discharge is increasing, and environmental pollution is becoming more and more serious. Therefore, the recycling and recycling of wastewater treatment and recycling resources The more attention comes to the attention of all countries. Especially in countries with severe water scarcity, per capita fresh water resources are small. Therefore, the recycling of sewage is the key to solving the shortage of fresh water resources. However, the current sewage treatment is mostly up to standard discharge, and there are not many mature wastewater recycling technologies, and less application to engineering practice. For example, in the total consumption of urban water resources in China, industrial water is about to take up. 2/3, if the sewage is recycled for industrial water, it will have great potential in water saving, which is equivalent to an increase of 2/3 of the total fresh water resources.

In recent years, environmental workers have done a lot of work in wastewater treatment and recycling. China patent CN200410024576.8 discloses a process and special equipment for sewage extraction and reclaimed water. It is treated with enzymes, then filtered and ozone. A method of producing reclaimed water by sterilization. Chinese patent CN101108760B discloses a method for recycling waste water that has reached the discharge standard after biochemical treatment through continuous microfiltration treatment, which is a tail water of biochemical water as a source water, passes through a swirling coagulation reaction tank, and is materialized by a multi-stage sedimentation tank. After precipitation, it enters the intermediate pool and is pumped to a continuous microfiltration system for advanced treatment to produce reclaimed water. Although there are many methods for wastewater reclamation, governments at all levels and environmental workers have done a lot of work in the recycling of wastewater, but the proportion of wastewater reuse in industrial water is less than 2%. The fields used are limited to industries that do not require high water quality, such as industrial slag dedusting water, cooling water, internal greening, flushing, etc., and few attempts are made in production process water with high water quality requirements. The reason for the analysis is mainly because the recycling of sewage in the industry has the following problems: 1. The quality of the reclaimed water is not high: firstly, it is difficult to remove the residual color and odor in the sewage by the existing sewage purification and regeneration technology, and the residual water remains. There are various nutrients and bacteria, molds, algae, etc., when exposed to appropriate temperature and light conditions, they will rapidly multiply and form unpleasant odors, resulting in difficult biological scales, which will also have adverse effects on process equipment, so that reclaimed water The application in industrial production is very limited; secondly, the total dissolved salt content in the sewage is high, and contains a large amount of calcium and magnesium salts which can form scale. When it is transported to the water processing equipment through the pipeline, it will be due to long-term electrochemistry. Corrosion, damage caused by the use of water equipment, as the calcium and magnesium salts in the water are circulated and concentrated in the water equipment, further forming scale, which may cause blockage of water equipment. 2, economically uneconomical: after biochemical treatment through reverse osmosis, although the sewage can be regenerated, but the one-time equipment investment is large, the operating cost is higher than the current tap water price, from the economical standard, still not satisfactory, reclaimed water treatment Recycling cannot achieve scale. 3. Secondary pollution: The traditional reclaimed water reuse technology usually uses the flocculant and bactericide to precipitate the microorganisms, colloids and solid particles in the water during the purification process of the sewage, and then passes through the sand filter, multi-media filtration and The membrane filtration purification process has the disadvantage of adding flocculant and disinfectant during the treatment process, which not only has large investment, high operating cost, but also causes flocculation and bactericide to cause different degrees of pollution to the environment. It can be seen from the above problems that research and development of reclaimed water recycling technology and supporting equipment suitable for China's economic status and development level, such as safety, reliability, high efficiency, low energy consumption, low investment and low regeneration cost, is the scale and industrialization of recycled water reuse. Laying a solid foundation has become an urgent task.

technical problem

The object of the present invention is to provide a kind of sewage for the sewage in the existing sewage recycling and recycling technology, which has poor quality of reclaimed water, is difficult to meet the water quality requirements of the production process, has large investment, high operating cost and secondary pollution to the environment. Advanced treatment and recycling, reducing sewage discharge, improving water use efficiency based on electrolysis and Wastewater recycling device and method for MBR technology.

Technical solution

The sewage recycling device based on electrolysis and MBR technology of the present invention is provided with an electrolysis system and an MBR system.

The electrolysis system is used for a treatment step of electrolysis, sedimentation, etc., the electrolysis system is provided with a shut-off valve, a water supply pump and an electrolysis machine, the inlet of the shut-off valve is externally connected with a biochemical water discharge port, and the inlet of the water supply pump is connected to the outlet of the shut-off valve. The outlet of the water supply pump is connected to the inlet of the electrolysis machine, and the outlet of the electrolysis machine is connected with the MBR system;

The MBR system is used for treating the purified sewage obtained by the electrolysis system, the MBR system is provided with a grid, an MBR reaction tank, an MBR component, a blower, an aerator, a sewage pump, a water discharge pump and a reclaimed water storage tank. The inlet of the grid is connected to the outlet of the electrolysis machine of the electrolysis system through the inlet pipe, the outlet of the grid is connected to the inlet of the MBR reaction tank, the MBR component is submerged in the MBR reaction tank, the blower and the aerator are used to aerate the MBR reactor, and the outlet of the MBR component The inlet of the water pump is taken out, and the outlet of the water pump is connected to the reclaimed water storage tank, and the sludge is sucked and discharged through the sewage pump.

The electrolysis machine may be a general electrolysis machine or a nano catalytic electrolysis machine or the like, which is composed of a power source and an electrolysis cell.

The anode in the electrolysis cell of the electrolysis machine is a nano catalytic electrode, the surface of the nano catalytic electrode is provided with a metal oxide inert catalytic coating with a crystal grain of 10 to 35 nm, and the substrate of the nano catalytic electrode can be a titanium plate or a plastic plate. This electrode has a high electrocatalytic reactivity and can greatly reduce the overpotential of electrolysis.

The MBR system may adopt a built-in MBR system or an external MBR system; the external MBR system is a membrane module installed outside the biochemical pool; the filter membrane of the MBR system may be selected from a polyvinylidene fluoride (PVDF) hollow a fiber membrane, a polypropylene (PP) hollow fiber membrane, a polysulfone (PS) hollow fiber membrane, a polyethersulfone (PES), a polyacrylonitrile (PAN), and a polyvinyl chloride (PVC) hollow fiber membrane; The filter membrane may have a pore diameter of 0.10 to 0.2 μm and can perform solid-liquid separation efficiently. The working pressure of the filtration membrane may be -1 to -50 kPa, the working temperature may be 5 to 45 ° C, and the pH may be 1 to 14. The suspended solids in the effluent can be reduced to 1 mg/L and the turbidity can be reduced to below 1 NTU. The system completely removes bacteria and E. coli from water, and the effluent coliform is 0, while the total number of bacteria is less than 1 CFU/ML.

The method for recycling wastewater based on electrolysis and MBR technology adopts the sewage recycling device based on electrolysis and MBR technology, and the method comprises the following steps:

1) After the biochemical treatment, the deep treated sewage from the secondary sedimentation tank is pumped, pumped into the electrolysis machine for electrolysis, and then passed through the grid into the MBR system to remove solid impurities, plankton, bacteria and colloids generated by electrolysis in the sewage. To purify sewage;

In step 1), the deep treatment sewage refers to sewage that has been biochemically treated to meet the discharge standard of GB18918-2002 "Industrial Wastewater Treatment Plant Pollutant Discharge Standard", and its COD Cr≤120 mg/L, BOD5≤60 mg/L, SS≤50mg/L, chromaticity less than 50, animal and vegetable oil ≤20 mg/L, petroleum ≤15 mg/ L, anionic surfactant ≤ 5 mg / L, ammonia nitrogen ≤ 25 mg / L, total phosphorus ≤ 5 mg / L, conductivity <1500 μs / cm, when the conductivity is > 1500 When μs/cm, it should be desalted with EDI after MBR;

The electrolysis is to electrolyze the deep treated sewage to form nascent chlorine [Cl], hydroxyl [OH] and nascent oxygen [O] for oxidative decomposition of animal and vegetable oil, petroleum, anionic surface active in sewage. Organic substances such as agents and colored substances, ammonia nitrogen, and at the same time, under the action of an electric field, the suspended solids, colloids and charged particles in the sewage are agglomerated to form larger particles;

The working voltage of the electrolysis may be 2 to 250 V, the voltage between two adjacent electrodes may be 2 to 18 V, the optimum voltage between two adjacent electrodes is 3 to 12 V, and the current density may be 5 to 300 mA/cm 2 . The best current density is 50-200 mA/cm2, and the advanced treated sewage enters the MBR system through the valve after electrolysis.

2) The purified sewage treated by the electrolysis system is flowed into the MBR system through the pipeline to perform solid-liquid separation, that is, the sewage recycling is completed. The suspended solids in the effluent can be reduced to 1 mg/L and the turbidity can be reduced to below 1 NTU. The system completely removes bacteria and E. coli from water, and the effluent coliform is 0, while the total number of bacteria is less than 1 CFU/ML.

The MBR system is a novel wastewater treatment technology which combines membrane separation technology and biological technology. It utilizes a membrane separation device to intercept activated sludge and macromolecular organic substances in a biochemical reaction tank, and has high biochemical efficiency and load shock resistance. Strong, small footprint and other advantages.

Beneficial effect

The technical scheme of the invention is: sewage after biochemical treatment → electrolysis → MBR system → Reclaimed water reuse. The secondary sedimentation tank wastewater (called advanced treatment wastewater) after the biochemical treatment of sewage is subjected to nano-catalytic electrolysis treatment before entering the MBR. Separation system processing. The technical route is used to solve the existing technical problems of wastewater reuse, and has the following advantages:

1) The nascent chlorine [Cl], hydroxyl [OH] and nascent oxygen [O] produced by electrolysis under the action of electricity The macromolecule remaining in the sewage is opened or broken and the organic matter is oxidized to improve the biodegradability of the sewage.

2) High water recovery rate and low cost Water recovery rate is as high as 70% to 90% The discharge of sewage is small, the energy consumption is low, and the production cost of reclaimed water is less than 1 yuan / ton, which is far lower than the cost of the biochemical rear end plus reverse osmosis membrane treatment.

3) Good decolorization effect The initial ecological chlorine [Cl], hydroxyl [OH] and nascent oxygen [O] produced by electrolysis The colored macromolecule remaining in the sewage is opened or broken, and the colored substance in the sewage is rapidly oxidized and decomposed, and the decolorization effect is good.

4) The traditional biochemical end-added membrane filtration technology can not reduce the total discharge of sewage COD, although it can realize partial water reuse. The nascent chlorine [Cl], hydroxyl [OH] and nascent oxygen [O] produced by the electrolysis of the present invention can rapidly oxidize and decompose organic substances in sewage, and greatly reduce the total discharge of sewage COD.

5 The use of electrolysis technology to replace the physicochemical treatment process of the secondary sedimentation tank sewage treatment, without the addition of chemical substances such as flocculant, decolorizer and air floatation agent, not only saves cost, but also saves material consumption and does not cause secondary pollution.

6) Adopting the invention When treating sewage, the electrolysis technology is used instead of the physicochemical process after the effluent from the secondary settling tank. The chemical substances such as flocculating agent and decolorizing agent are not added, and the sludge is greatly reduced. The sludge is only one-half of the conventional technology.

7) The membrane module is directly placed in the biochemical pool, the production process is short, the equipment structure is compact, and the land occupation is small.

8) MBR The system utilizes membrane separation equipment to intercept activated sludge and macromolecular organic substances in the biochemical reaction tank, which has high biochemical efficiency and strong resistance to load shock. The operating pressure is low, the investment in fixed assets is greatly reduced, and the energy consumption during equipment operation is greatly reduced.

9) The use of electrolysis has the following outstanding effects: (1) under the action of current, the nascent chlorine [Cl], hydroxyl [OH] and nascent oxygen [O] produced by electrolysis open the macromolecules remaining in the sewage. Ring or chain scission and oxidize organic matter to improve the biodegradability of sewage. (2) Oxidative decomposition of ammonia nitrogen in the sewage to further oxidize residual ammonia nitrogen, and the removal rate of ammonia nitrogen can reach 80 to 90%, and at the same time eliminate odor in water. (3) The chromaticity of the sewage is greatly reduced. After the treatment by biochemical, physicochemical and other methods, the chromaticity of the advanced treatment of the secondary sedimentation tank is between 80 and 300. The general treatment method is difficult to further decolorize. Nano-catalytic electrolysis can reduce the chroma of deep treated sewage from 80 to 300 to 16 to 32. (4) Oxidative decomposition of organic matter in sewage, residual dyes rapidly reduce COD _Cr . (5) After the suspended solids, colloids and charged particles in the sewage are condensed under the action of an electric field to form larger particles, the purified sewage is removed by filtration. (6) The heavy metal ions in the sewage move to the cathode of the electrolysis cell of the electrolysis machine to form a precipitate at the cathode, thereby reducing the heavy metal ion content in the sewage.

DRAWINGS

1 is a schematic view showing the structural composition of an embodiment of a sewage recycling device based on electrolysis and MBR technology according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The invention is a design process for purifying and recycling deep treated sewage after in-depth systematic comparison research on the composition, properties and existing treatment schemes of the existing advanced treated sewage, which passes through the electrolysis system and the MBR system. The combined use of the unified methods to form a purification and recycling method that is particularly suitable for the deep treatment of sewage.

The invention will be further illustrated by the following examples in conjunction with the accompanying drawings.

Referring to Fig. 1, an embodiment of a sewage recycling device based on electrolysis and membrane technology according to the present invention is provided with an electrolysis system and an MBR. System.

Electrolysis system: The electrolysis system is used for treatment steps such as electrolysis and sedimentation. The electrolysis system is provided with a shut-off valve 11 , a water supply pump 12 , and an electrolysis machine 13 . The inlet of the shut-off valve 11 is externally connected with the biochemical water discharge port P1, the inlet of the water supply pump 12 is connected to the outlet of the shut-off valve 11, and the outlet of the water supply pump 12 is connected to the inlet of the electrolysis machine 13, the electrolysis machine 13 The exit is connected to the MBR system.

MBR system: The MBR system is used to filter the purified sewage from the electrolysis system. The MBR system is provided with a grille 21 , MBR component 22, MBR reaction cell 23, blower 24, aerator 25, sewage pump 26, water pump 27, reclaimed water storage tank 28 . The purified sewage obtained by the electrolysis system is connected to the inlet of the grille 21 through the inlet pipe, and the outlet of the grill 21 is connected to the inlet of the MBR reaction tank 23. MBR component 22 immersed in the MBR reaction cell 23 Inside, the air blower 24 and the aerator 25 provided are aerated. The outlet of the MBR assembly 22 receives the inlet of the water pump 27, and the resulting filtrate (water) is collected into the reclaimed water storage tank. Recycled water that has been recycled (see P3 in Figure 1), a small amount of sludge is pumped through the sludge discharge port P2 of the sewage pump 26.

The method for recycling wastewater based on electrolysis and MBR technology, using the electrolysis-based and MBR A technical sewage recycling plant, the method comprising the steps of:

Step 1 : Electrolysis: After the biochemical treatment, the deep treated sewage of the secondary settling tank reaches the discharge standard is extracted by the water pump 12, and then input into the electrolysis machine. In the 13th, the nano-catalytic electrolysis is carried out, and the solid impurities, plankton, bacteria and colloids generated by the nano-catalytic electrolysis in the sewage are removed by filtration through the grid 21 and then enter the reaction cell 23 of the MBR system.

The working voltage of the nano catalytic microelectrolysis may be 2 to 250V, the voltage between two adjacent electrodes is 2 to 18V, the optimum voltage between two adjacent electrodes is 3 to 12V, and the current density is 5 to 300mA/ Cm ² , the best current density is 50 ~ 200mA / cm ² , the deep treatment sewage after electrolysis through the valve into the sedimentation tank.

The electrolysis is to subject the deep treated sewage to nano-catalytic electrolysis to form nascent chlorine [Cl], hydroxyl [OH] and nascent oxygen. [O], use Oxidative decomposition of animal and vegetable oils, petroleum, anionic surfactants, colored substances and other organic substances in the sewage, ammonia nitrogen, and killing microorganisms in the sewage, and at the same time, under the action of electric field, the suspended solids, colloids and charged particles in the sewage are aggregated to form Larger particles.

The advanced treatment sewage refers to sewage that has been biochemically treated to meet discharge standards, and its COD Cr is less than 120 mg/L. , BOD5 less than 60 mg / L , SS less than 50mg / L , color less than 50 , animal and vegetable oil 20 mg / L , petroleum 15 mg / L , anionic surfactant 5 mg / L, ammonia nitrogen 25 mg / L, total phosphorus 5 mg / L, conductivity less than 1500 μs / cm. When the conductivity is greater than 1500 μs/cm When using MBR, desalinate with EDI.

The nano catalytic electrolysis has the following outstanding effects:

(1) The nascent chlorine [Cl], hydroxyl [OH] and nascent oxygen produced by nanocatalytic electrolysis under the action of current [O] Open or break the macromolecules in the sewage to improve the biodegradability of the sewage.

(2) Oxidative decomposition of ammonia nitrogen in the sewage to further oxidize residual ammonia nitrogen, and the removal rate of ammonia nitrogen can reach 80% to 90%. At the same time, eliminate the smell of water.

(3 Oxidative decomposition of colored substances in sewage, greatly reducing the color of sewage: after biochemical, physicochemical and other methods of treatment, there are some macrocyclic compounds and long-chain compounds in the deep treatment of secondary sedimentation tanks, most of which have a certain color, so that the color of the sewage is Between 80 and 300, the chemical nature of these compounds is stable, and general treatment methods are difficult to further oxidize or decompose. The nascent chlorine [Cl], hydroxyl [OH] and nascent oxygen [O] produced by electrolysis The colored macromolecules remaining in the sewage can be opened or broken, rapidly oxidize and decompose the colored substances in the sewage, and the decolorization effect is good, so that the color of the sewage is reduced from 80 to 300 to 16 to 32. .

(4) Oxidative decomposition of organic matter in sewage, residual dyes rapidly reduce COD _Cr .

(5 The suspended solids, colloids and charged particles in the sewage are condensed under the action of an electric field to form larger particles, and then the purified sewage is removed by filtration.

(6 The heavy metal ions in the sewage move to the cathode of the electrolysis cell and form a precipitate at the cathode, thereby reducing the heavy metal ion content in the sewage.

Step 2: Separation of the MBR system: the purified sewage treated by the electrolysis system flows into the MBR system reaction tank through the pipeline. In the middle, the blower 24 and the aerator 25 are activated, and after the aeration oxidation, the water pump 27 is started, and the suction pressure of the water pump 27 generates a negative pressure, and under the action of the negative pressure, the water molecules pass through the MBR component. Separation.

The membrane material of the MBR system is a PP hollow fiber membrane, and the membrane pore diameter is 0.16-0.2 μm, which can perform solid-liquid separation efficiently, and the working pressure is -1 to -50 kPa, the working temperature is 5 to 45 ° C, and the operating pH is 1 -. 14, the effluent fixed suspension can be reduced to 1mg / L, the turbidity can be reduced to below 1NTU. The system completely removes bacteria and E. coli from water, and the effluent coliform is 0, while the total number of bacteria is less than 1 CFU/ML.

Embodiments of the invention

A specific embodiment of a deep treatment wastewater recycling method based on electrolysis and MBR technology is given below in conjunction with FIG.

Example 1: 500 ton / day advanced treatment of sewage purification and recycling project.

The measured indexes of the sewage are shown in Table 1.

Table 1

Serial number	project	unit	measured value	Serial number	project	unit	measured value
1	COD _Cr	Mg/ L	56	5	Turbidity		19
2	BOD ₅	Mg/ L	7	6	Chroma		60
3	SS	Mg/ L	13	7	pH		7.3
4	NH ₃ -N	Mg/ L	twenty three	8	Conductivity	μS/cm	410

Step 1. Electrolysis: The water supply pump 12 is started, and the sewage enters the electrolysis machine 13 through the shut-off valve 11 at a flow rate of 21 m ³ /h for electrolysis. The electrolysis has an operating voltage of 12V, a voltage between the two electrodes of 3.5 to 8.2 V, and a current density of 130 mA/cm ² . Under the action of current, the nascent chlorine [Cl], hydroxyl [OH] and nascent Oxygen [O] causes the macromolecules in the sewage to be opened or broken, which improves the biodegradability of the sewage. At the same time, the organic matter, ammonia nitrogen, colored substances in the wastewater are oxidatively decomposed, and the suspended solids, colloids and charged particles in the wastewater form larger particles under the action of the electric field. The indexes of the treated sewage in the electrolysis system are shown in Table 2.

Table 2 Sewage water quality indicators after electrolysis

Serial number	project	unit	measured value	Serial number	project	unit	measured value
1	COD _Cr	Mg/ L	43	5	Turbidity	NTU	9
2	BOD ₅	Mg/ L	19	6	Chroma		4
3	SS	Mg/ L	33	7	pH		7.4
4	NH ₃ -N	Mg/ L	3	8	Conductivity	μS/cm	410

Step 2, MBR system separation: the electrolyzed sewage passes through the grid 21 The solid impurities, plankton, bacteria and colloids generated by electrolysis in the sewage are filtered to enter the reaction cell 23 of the MBR system, and the blower 24 and the aerator 25 are activated, and after the aeration oxidation, the water pump is started. 27, under the action of negative pressure, the water molecules are separated by the MBR component 22 to obtain dialysis water, and the dialysis water is collected into the reclaimed water storage tank 28, the yield is 80%, and the quality of the recycled water is shown in Table 3. Shown.

The membrane material of the MBR system was a 0.2 μm polyvinylidene fluoride (PVDF) hollow fiber membrane.

The working pressure of the MBR system is -25 ～ -26 Kpa, and the working temperature is 15 ～ 40 °C. The pH is 5 to 9 .

table 3

Serial number	project	unit	measured value	Serial number	project	unit	measured value
1	Sensory index		Colorless and tasteless	6	Chroma		1
2	COD _Cr	Mg/ L	30	7	pH		7.2
3	BOD ₅	Mg/ L	1	8	NH ₃ -N	Mg/ L	1
4	SS	Mg/ L	0	9	total hardness	Mg/ L	20
5	Turbidity	NTU	1	10	Conductivity	μS/cm	410

Example 2: 3000 ton / day Depth Treatment Industrial wastewater purification and recycling project.

The measured indicators of the sewage are shown in Table 4.

Table 4

Serial number	project	unit	measured value	Serial number	project	unit	measured value
1	COD _Cr	Mg/ L	116	5	Turbidity		15
2	BOD ₅	Mg/ L	16	6	Chroma		80
3	SS	Mg/ L	twenty three	7	pH		7.7
4	NH ₃ -N	Mg/ L	16	8	Conductivity	μS/cm	560

Step 1. Electrolysis: The water supply pump 12 is started, and the sewage enters the electrolysis machine 13 through the shut-off valve 11 at a flow rate of 137 m ³ /h for electrolysis. The working voltage of electrolysis is 48V, the voltage between the two poles is 5.5 ~ 8.2V, and the current density is 190mA/cm ² . Under the action of current, the nascent chlorine [Cl], hydroxyl [OH] and nascent oxygen produced by electrolysis [O], the macromolecules in the sewage are opened or broken, and the biodegradability of the sewage is improved. At the same time, the organic matter, ammonia nitrogen, colored substances in the wastewater are oxidatively decomposed, and the suspended solids, colloids and charged particles in the wastewater form larger particles under the action of the electric field. The sewage indexes after treatment by the electrolysis system are shown in Table 5.

Table 5 Sewage water quality indicators after electrolysis

Serial number	project	unit	measured value	Serial number	project	unit	measured value
1	COD _Cr	Mg/ L	81	5	Turbidity	NTU	7
2	BOD ₅	Mg/ L	43	6	Chroma		8
3	SS	Mg/ L	35	7	pH		7.8
4	NH ₃ -N	Mg/ L	1	8	Conductivity	μS/cm	560

Step 2, MBR system separation: the electrolyzed sewage passes through the grid 21 The solid impurities, plankton, bacteria and colloids generated by electrolysis in the sewage are filtered to enter the reaction cell 23 of the MBR system, and the blower 24 and the aerator 25 are activated, and after the aeration oxidation, the water pump is started. 27, under the action of negative pressure, the water molecules are separated by the MBR component 22 to obtain dialysis water, and the dialysis water is collected into the reclaimed water storage tank 28, the yield is 75%, and the quality of the recycled water is shown in Table 6. Shown.

The membrane material of the MBR system is a polypropylene (PP) hollow fiber membrane having a pore size of 0.2 μm.

The working pressure of the MBR system is -20 to -23 Kpa, and the working temperature is 5 to 4 5 °C. .

Table 6

Serial number	project	unit	measured value	Serial number	project	unit	measured value
1	Sensory index		Colorless and tasteless	6	Chroma		2
2	COD _Cr	Mg/ L	28	7	pH		7.1
3	BOD ₅	Mg/ L	1	8	NH ₃ -N	Mg/ L	1
4	SS	Mg/ L	0	9	total hardness	Mg/ L	twenty three
5	Turbidity	NTU	1	10	Conductivity	μS/cm	510

Industrial applicability

The technical solution of the invention solves the technical problem of the existing sewage reuse technology, the water recovery rate is high, the cost is low, the decolorization effect is good, and the chemical substances such as the flocculating agent, the decolorizing agent and the air floating agent are not added, which not only saves cost but also saves the material. Consumption and no secondary pollution, greatly reduced sludge, sludge is only one-half of the traditional technology, short process, compact equipment, small footprint, high biochemical efficiency, strong impact resistance, operating pressure Low, fixed asset investment has been greatly reduced, energy consumption during equipment operation has dropped significantly, and it has good industrial applicability.

Sequence table free content

Claims

A sewage recycling device based on electrolysis and MBR technology, characterized in that an electrolysis system and an MBR system are provided;

The electrolysis system is used for electrolysis and sedimentation processing steps. The electrolysis system is provided with a shut-off valve, a water supply pump and an electrolysis machine, and an inlet of the shut-off valve is externally connected with a biochemical water discharge port, and an inlet of the water supply pump is connected to an outlet of the shut-off valve for supplying The outlet of the water pump is connected to the inlet of the electrolysis machine, and the outlet of the electrolysis machine is connected with the MBR system;

The MBR system is used for treating the purified sewage obtained by the electrolysis system, the MBR system is provided with a grid, an MBR reaction tank, an MBR component, a blower, an aerator, a sewage pump, a water discharge pump and a reclaimed water storage tank. The inlet of the grid is connected to the outlet of the electrolysis machine of the electrolysis system through the inlet pipe, the outlet of the grid is connected to the inlet of the MBR reaction tank, the MBR component is submerged in the MBR reaction tank, the blower and the aerator are used to aerate the MBR reactor, and the outlet of the MBR component The inlet of the water pump is taken out, and the outlet of the water pump is connected to the reclaimed water storage tank, and the sludge is sucked and discharged through the sewage pump.
The sewage recycling device based on electrolysis and MBR technology according to claim 1, wherein the anode in the electrolytic cell of the electrolysis machine is a nano catalytic electrode, and the surface of the nano catalytic electrode is provided with a crystal grain of 10 to 35 nm. Inert catalytic coating of metal oxide.
The sewage recycling device based on electrolysis and MBR technology according to claim 1, wherein the filter membrane of the MBR system is selected from the group consisting of a polyvinylidene fluoride hollow fiber membrane, a polypropylene hollow fiber membrane, a polysulfone hollow fiber membrane, One of a polyethersulfone hollow fiber membrane, a polyacrylonitrile hollow fiber membrane, and a polyvinyl chloride hollow fiber membrane.
The sewage recycling device based on electrolysis and MBR technology according to claim 1 or 3, wherein the filtration membrane has a pore diameter of 0.10 to 0.2 μm, and the filtration membrane has a working pressure of -1 to -50 kPa, and works. The temperature is 5 to 45 ° C and the pH is 1 to 14.
A method of wastewater recycling based on electrolysis and MBR technology, characterized by using a sewage recycling apparatus based on electrolysis and MBR technology according to claims 1 to 4, the method comprising the steps of:

1) After the biochemical treatment, the deep treated sewage from the secondary sedimentation tank is pumped, pumped into the electrolysis machine for electrolysis, and then passed through the grid into the MBR system to remove solid impurities, plankton, bacteria and colloids generated by electrolysis in the sewage. To purify sewage;

2) The purified sewage treated by the electrolysis system is flowed into the MBR system through the pipeline to perform solid-liquid separation, that is, the sewage recycling is completed.
The method for recycling wastewater according to the electrolysis and MBR technology according to claim 5, wherein in the step 1), the deep treated sewage refers to sewage treated by biochemical treatment to reach GB18918-2002 "industrial sewage treatment plant pollutants Emission standard "emission standard of sewage, its COD Cr≤120 mg/L, BOD5≤60 mg/L, SS≤50mg/L, chromaticity less than 50, animal and vegetable oil ≤20 mg/L, petroleum ≤15 mg/ L, anionic surfactant ≤ 5 mg / L, ammonia nitrogen ≤ 25 mg / L, total phosphorus ≤ 5 mg / L, conductivity <1500 μs / cm, when the conductivity is > 1500 When μs/cm, it should be desalted with EDI after MBR.
The method for recycling wastewater according to the electrolysis and MBR technology according to claim 5, wherein in the step 1), the electrolysis is to electrolyze the deep treated sewage to form nascent chlorine [Cl] and hydroxyl groups. [OH] and nascent oxygen [O], used to oxidize and decompose animal and vegetable oils, petroleum, anionic surfactants, organic matter of colored substances, ammonia nitrogen in sewage, and at the same time, make suspended matter and colloid in sewage under the action of electric field. The charged particles aggregate to form larger particles.
The method for recycling wastewater according to the electrolysis and MBR technology according to claim 5, wherein in the step 1), the working voltage of the electrolysis is 2 to 250 V, and the voltage between two adjacent electrodes is 2 to 18V, the current density is 5 ~ 300mA / cm2, the advanced treatment of sewage through the electrolysis and enter the MBR system through the valve.
A method of recycling wastewater according to the electrolysis and MBR technology according to claim 8, wherein the voltage between the adjacent two electrodes of the electrolysis is 3 to 12 V, and the current density is 50 to 200 mA/cm2.