CN106396211A - Electrocoagulation and ceramic micro-filtration membrane coupling device for purifying micro-polluted source water as well as process - Google Patents

Abstract

The coupling device and process for purifying micro-polluted source water by electrocoagulation ceramic microfiltration membranes provided by the present invention include submersible pumps, raw water tanks, water inlet pumps for electrocoagulation reactors, electrocoagulation reactors, intermediate water storage tanks, and ceramic microfiltration membrane components. Water pump, ceramic microfiltration membrane module, backwash water tank, clean water tank, air compressor, concentrated water discharge pipe, concentrated water return pipe, concentrated water pipe, permeate water/backwash water conversion pipe, backwash drain pipe and air pipe, The device has simple equipment, compact structure, high treatment efficiency, and convenient maintenance and management. It combines the advantages of electrocoagulation technology and ceramic microfiltration membrane technology, which not only improves the water quality of the ceramic microfiltration membrane, delays the attenuation of the membrane flux, but also overcomes the It eliminates the defects of high energy consumption and long solid-liquid separation time of electrocoagulation, achieves the purpose of complementary advantages, and is suitable for popularization and application.

Description

Coupling device and process for purifying slightly polluted source water by electrocoagulation ceramic microfiltration membrane

technical field

The invention relates to a coupling device and a process for purifying slightly polluted source water by an electrocoagulation ceramic microfiltration membrane, belonging to the field of water pollution control.

Background technique

In the water supply treatment industry, the traditional water purification process based on coagulation, sedimentation, filtration, and disinfection targets water bodies that meet drinking water source water standards. The effect of microbial treatment is obvious, and the water quality is easier to meet the standard. However, with the development of human society, the discharge of various organic substances into water bodies has accelerated the deterioration of water sources, and some indicators are higher than the standard limit requirements for Class III water bodies in the "Environmental Quality Standards for Surface Water" (GB3838-2002). For this kind of slightly polluted source water, the traditional water purification process is difficult to make the water meet the requirements of the "Drinking Water Hygienic Standard" (GB5749-2006), so as to ensure the safety of drinking water.

Membrane technology, as the fourth generation of water treatment process, has attracted more and more attention due to its unique advantages, especially the ceramic microfiltration membrane, which has stable chemical properties, acid and alkali resistance, organic solvents and microbial erosion, high mechanical strength and low energy consumption. , not easy to block, long service life, anti-extreme weather and other characteristics. However, in actual operation, when ceramic microfiltration membranes are used to treat source water with high organic content such as pond water and reservoir water, not only the membrane flux decays rapidly, the membrane pores are severely clogged, and the water production rate drops sharply, but also the organic matter in the water. The removal rate is low, which threatens the safety of water supply. Existing chemical coagulation pretreatment before the membrane, such as micro-flocculation, membrane filtration and air flotation integrated reaction device and its method for treating low-turbidity and micro-polluted water (application number: 201010566493.7), but the addition of chemical flocculant Larger volume, larger sludge output, easy to form secondary pollution, and longer hydraulic retention time.

Electrocoagulation technology is used in the field of water treatment. The advantages are: simple equipment, compact structure, small footprint, convenient operation and maintenance, and easy coupling with other processes; the metal ions generated by the reaction have no impurities, pure components, small sludge output, and electrode Low metal consumption; wide adaptability to raw water, no need to add chemical agents during the reaction process, no problem of agent storage, no risk of secondary pollution; metal ions generated by electrode dissolution have high activity and strong flocculation performance , The micro-bubbles formed can also complete the flotation of particles while stirring, and the treatment efficiency is high. However, the defects of high energy consumption and long processing time have restricted the popularization and application of electrocoagulation technology.

Electrocoagulation is used as the pretreatment of ceramic microfiltration membrane. The impurities in the water first pass through the electrocoagulation reactor, some impurities are oxidized and removed, and some destabilize to form tiny flocs, which are then intercepted and filtered by the ceramic microfiltration membrane. Different from some existing water purification devices with electrocoagulation-ultrafiltration membrane technology as the core, such as a combined process and device for treating slightly polluted water (application number: 201410342465.5), this patent uses organic hollow fiber ultrafiltration membrane intermittently In operation, the operating pressure is high, the energy consumption is high, and the membrane pores are small and easy to block. At the same time, the internal pressure hollow fiber membrane is not easy to clean, and the flux recovery is poor. In addition, the organic hollow fiber membrane is easy to enrich microorganisms, aging and breaking, which is not easy to detect, and pollutes the effluent. In contrast, the use of tubular ceramic microfiltration membranes has lower working pressure, saves energy consumption, larger membrane pores are not easy to block, easy to clean after membrane fouling, and resists physical and chemical cracking and microbial degradation. Therefore, the coupling process combining the advantages of electrocoagulation technology and ceramic microfiltration membrane technology not only improves the water quality of ceramic microfiltration membrane, delays the attenuation of membrane flux, but also overcomes the high energy consumption of electrocoagulation and long solid-liquid separation time. Defects, to achieve the purpose of complementary advantages.

Contents of the invention

Aiming at the deficiencies in the above-mentioned prior art, the present invention provides a coupling device for purifying slightly polluted source water by electroflocculation ceramic microfiltration membrane with compact structure, stable performance, simple process and high treatment efficiency.

In order to achieve the above object, the present invention provides the following technical solutions: a coupling device for electrocoagulation ceramic microfiltration membrane to purify slightly polluted source water, including a submersible pump, a raw water tank, an electrocoagulation reactor inlet pump, an electrocoagulation reactor, a DC stabilizer Piezoelectric power supply, intermediate water storage tank, ceramic microfiltration membrane module inlet pump, ceramic microfiltration membrane module, backwash water tank, clean water tank, air compressor, concentrated water discharge pipe, concentrated water return pipe, concentrated water pipe, permeate water/reverse Washing water conversion pipe, backwash drain pipe and air pipe, the water inlet of the raw water tank is connected to the submersible pump through the pipeline, and the water outlet is connected to the electroflocculation reactor through the water inlet pump of the electroflocculation reactor, and the electroflocculation reactor passes through The wire is connected to the DC stabilized power supply, the water outlet of the electrocoagulation reactor is connected to the water inlet of the intermediate water storage tank, and the water outlet of the intermediate water storage tank is connected to the ceramic microfiltration membrane module through the ceramic microfiltration membrane module water inlet pump. The bottom of the ceramic microfiltration membrane module is provided with a backwash drainage pipe connected thereto. The concentrated water pipe at the top of the ceramic microfiltration membrane module is connected to the concentrated water discharge pipe and the concentrated water return pipe through a tee, and the concentrated water return pipe is connected to the concentrated water return pipe. The intermediate water storage tank is connected, and the water outlet of the ceramic microfiltration membrane module is connected to the backwash water tank through the permeate water/backwash water conversion pipe. The water outlet of the backwash water tank is connected to the clean water tank, and the upper end is connected to an air compressor through an air pipe .

Preferably, the electrocoagulation reactor includes electrode plates, conductive copper rods, a plexiglass shell and a bracket for placing the electrode plates, and the electrode plates are arranged in series and parallel and staggered in the plexiglass shell through conductive rods.

Preferably, a base and a blowdown pipe are provided at the bottom of the electrocoagulation reactor.

Preferably, the ceramic microfiltration membrane module adopts a tubular internal pressure ceramic microfiltration membrane.

A kind of technology with above-mentioned coupling device, comprises the steps:

1) The source water is injected into the raw water tank through the submersible pump, and then pressed into the electrocoagulation reactor through the electroflocculation reactor inlet pump. The outlet of the electroflocculation reactor inlet pump is equipped with a valve and a flow meter to adjust the inlet water flow of the electroflocculation reactor The constant is 4L/min, and then the residence time of the water body in the electrocoagulation reactor is controlled to be 150s. In the electrocoagulation reactor, 8 pure aluminum plates with a thickness of 3mm are arranged in parallel as electrode plates, and a Φ10 through hole is opened on the top of the plate to pass through the conductive copper rod. Single-stage connection, the lower end of the plate is placed on the bracket, and the distance between the plates is 10mm;

2) Start the DC stabilized power supply, adjust the output current according to the raw water quality to make the current density float between 0.5-3.0mA/ ^cm2 ;

3) The water treated by electrocoagulation enters the intermediate water storage tank under the action of gravity, and stays for 300s to form tiny flocs;

4) After the reaction in step 3), the water body is pumped into the ceramic microfiltration membrane module through the ceramic microfiltration membrane module inlet pump. The ceramic microfiltration membrane module adopts a cross-flow filtration mode, in which two pore pipe-type internal pressure ceramic microfiltration membranes are filled , each membrane is 500mm long, connected in series, made of Al ₂ O ₃ , the membrane pore size is 200nm, part of the concentrated water is discharged through the concentrated water discharge pipe, and part of it is returned to the intermediate water storage tank through the concentrated water return pipe to make full use of the unreacted metal Ions and permeate water enter the backwash water tank and clean water tank, control the transmembrane pressure difference to 0.1MPa through the valve on the water inlet pipe of the ceramic membrane module, and adjust the valve on the two branch pipes of the concentrated water pipe to control the reflux ratio to 20%;

5) When the water production of the device decays rapidly, close the valves on the outlet of the ceramic microfiltration membrane module inlet pump and the water inlet pipe of the clean water tank, open the valves on the backwash drain pipe and the air pipe, and start the air compressor to backwash the ceramic microfiltration At the same time, open the sewage pipe to remove the sludge at the bottom of the electrocoagulation reactor, and exchange the positive and negative electrodes of the electrode plate.

As can be seen from the above technical solutions, the present invention has the following advantages compared with other existing technologies:

(1) The adoption of electrocoagulation technology can absorb and trap impurities in water through the new ecological hydroxyl complex formed by the anode; and through the redox effect in electrocoagulation, it can degrade and remove some organic matter; in addition, a large number of tiny The small size of the bubbles and the large specific surface area have a strong ability to adsorb and float suspended solids, colloids, and flocs with dispersed structures, which can improve the removal rate of organic matter by membrane technology, delay membrane fouling, and increase the membrane cleaning cycle.

(2) The application of tubular ceramic microfiltration membrane can significantly improve the separation efficiency of solid and liquid after electrocoagulation treatment, save floor space and reduce energy consumption; at the same time, the tubular ceramic microfiltration membrane has stable physical, chemical and biological properties, high mechanical strength, Long service life, convenient storage, easy backwashing.

(3) Combining the advantages of electrocoagulation and ceramic microfiltration membranes, it not only improves the water quality of ceramic microfiltration membranes, delays the attenuation of membrane flux, but also overcomes the defects of high energy consumption and long solid-liquid separation time of electrocoagulation. The device has a compact structure, wide adaptability to water sources, high treatment efficiency, and is easy to realize automatic control.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a structural schematic diagram of the electrocoagulation reactor in the present invention.

detailed description

The present invention will be described in further detail below in conjunction with specific embodiments and accompanying drawings.

A coupling device for purifying micro-polluted source water with electrocoagulation ceramic microfiltration membrane as shown in Fig. 1 and Fig. 2, comprising a submersible pump 1, a raw water tank 2, an electrocoagulation reactor inlet pump 3, an electrocoagulation reactor 4, a direct current Stabilized power supply 5, intermediate water storage tank 7, ceramic microfiltration membrane module inlet pump 8, ceramic microfiltration membrane module 9, backwash water tank 10, clean water tank 11, air compressor 12, concentrated water removal pipe 15, concentrated water backflow Pipe 16, concentrated water pipe 17, permeate water/backwash water conversion pipe 18, backwash drain pipe 19 and air pipe 20, the water inlet of the raw water tank 2 is connected to the submersible pump 1 through a pipe, and the water outlet passes through the electroflocculation reactor The water inlet pump 3 is communicated with the electrocoagulation reactor 4, and the electrocoagulation reactor 4 is connected with the DC stabilized power supply 5 through a wire 13, and the water outlet of the electrocoagulation reactor 4 is communicated with the water inlet of the intermediate water storage tank 7, and the Electrocoagulation reactor 4 comprises electrode plate 21, conductive copper rod 22, plexiglass shell 23 and the bracket 24 that is used to place electrode plate 21, and this electrode plate 21 is arranged in series and parallel staggeredly in plexiglass shell 23 through conductive rod 22 According to the amount of treated water, the number of electrode plates 21 can be increased or decreased, and the aspect ratio of the electrode plates 21 can be adjusted; Fe, Al, Mg or alloy materials can be selected as the electrode plate 21 according to the raw water quality. The new ecological hydroxyl complex formed absorbs and catches impurities in the water; and through the redox effect in electrocoagulation, it can degrade and remove some organic matter; in addition, a large number of tiny bubbles generated by the cathode are small in size and large in specific surface area. The flocs with evacuated structure have strong adsorption and floating load capacity, which can improve the removal rate of organic matter by membrane technology, delay membrane fouling, and increase the membrane cleaning cycle. The filter membrane assembly 9 is connected, and the ceramic microfiltration membrane assembly 9 adopts a tubular internal pressure ceramic microfiltration membrane, made of Al ₂ O ₃ , in a cross-flow filtration mode. When it is necessary to increase the water production, multiple ceramic microfiltration membranes can be connected in parallel. Membranes, or ceramic microfiltration membranes with multiple channels; when it is necessary to increase the quality of the effluent, multi-stage filtration in series can be used, or small-pore ceramic microfiltration membranes can be filled. The use of tubular ceramic microfiltration membranes can significantly improve electrocoagulation treatment. The separation efficiency of solid and liquid can save floor space and reduce energy consumption; at the same time, the tubular ceramic microfiltration membrane has stable physical, chemical and biological properties, high mechanical strength, long service life, convenient storage, and easy backwashing. The bottom of the assembly 9 is provided with a backwash drain pipe 19 connected thereto, and the concentrated water pipe 17 at the top of the ceramic microfiltration membrane assembly 9 is connected with the concentrated water discharge pipe 15 and the concentrated water return pipe 16 through a tee, and the concentrated water returns The pipe 16 is connected to the intermediate water storage tank 7, and the water outlet of the ceramic microfiltration membrane module 9 communicates with the backwash water tank 10 via the permeate water/backwash water conversion pipe 18, and the water outlet of the backwash water tank 10 is connected to the clean water tank 11, The upper end is connected with an air compressor 12 through an air pipe 20 .

A kind of technology with above-mentioned coupling device, comprises the steps:

1) The source water is injected into the raw water tank 2 through the submersible pump 1, and then pressed into the electrocoagulation reactor 4 through the electrocoagulation reactor inlet pump 3, and the outlet of the electroflocculation reactor inlet pump 3 is equipped with a valve and a flow meter for adjusting the electrocoagulation reaction The influent flow rate of the device 4 is constant at 4L/min, and then the residence time of the water body in the electrocoagulation reactor 4 is controlled to be 150s. As shown in Figure 2, eight 3mm thick pure aluminum plates are arranged in parallel in the electrocoagulation reactor 4 as electrodes Plate 21, the through hole of Φ10 on the top of the plate is connected in a single-stage manner through a conductive copper rod 22, the lower end of the plate is placed on the bracket 24, and the distance between the plates is 10mm;

2) Start the DC stabilized power supply 5, and adjust the output current according to the raw water quality to make the current density float between 0.5-3.0mA/cm ² ;

3) The water treated by electrocoagulation enters the intermediate water storage tank 7 under the action of gravity, and stays for 300s to form tiny flocs;

4) After the reaction in step 3), the water body is pumped into the ceramic microfiltration membrane module 9 through the ceramic microfiltration membrane module inlet pump 8, and the ceramic microfiltration membrane module 9 adopts a cross-flow filtration mode, which is filled with two 19-hole pipe-type internal pressure Ceramic microfiltration membranes, each membrane is 500mm long, connected in series, made of _Al2O3 , with a membrane pore size of 200nm, part of the concentrated water is discharged through the concentrated water discharge pipe ₁₅ , and part of it is returned to the intermediate water storage tank 7 through the concentrated water return pipe 16 to Make full use of unreacted metal ions, permeate water into the backwash water tank 10 and clean water tank 11, control the transmembrane pressure difference to 0.1MPa through the valve on the water inlet pipe of the ceramic membrane module 9, and adjust the valve control on the two branch pipes of the concentrated water pipe The reflux ratio is 20%;

5) When the water production rate of the device decays rapidly, close the valves on the outlet of the ceramic microfiltration membrane module inlet pump 8 and the inlet pipe of the clean water tank 11, open the valves on the backwash drain pipe 19 and the air pipe 20, and start the air compressor 12 The ceramic microfiltration membrane is backwashed, and at the same time, the sewage pipe 14 is opened to remove the sludge at the bottom of the electrocoagulation reactor 4, and the positive and negative poles of the electrode plate 21 are exchanged.

The coupling device and process for purifying slightly polluted water source water with the above-mentioned electrocoagulation ceramic microfiltration membrane were used to treat lake water in a certain place. The raw water quality was tested as follows: temperature 23°C, pH 8.2, turbidity 9.61NTU, COD _Mn 6.29mg/L , UV ₂₅₄ is 0.169cm ^-1 , and the quality of the effluent water is shown in Table 1. It can be seen from Table 1 that under the same other conditions, the effluent water is the best when the current density is 2.0mA/cm ² and meets the Hygienic Standard for Drinking Water ( GB5749-2006) limit requirements.

Table 1 The effluent quality after electrocoagulation-ceramic microfiltration membrane coupling process treatment

The present invention constructs a combined process of dynamic and continuous operation, which combines the advantages of electrocoagulation and ceramic microfiltration membranes, not only improves the water quality of ceramic microfiltration membranes, delays the attenuation of membrane flux, but also overcomes the energy consumption of electrocoagulation High, the defect of long solid-liquid separation time. The device has a compact structure, wide adaptability to water sources, high treatment efficiency, and is easy to realize automatic control. The adoption of electrocoagulation technology can absorb and trap impurities in water through the new ecological hydroxyl complex formed by the anode; and through electrocoagulation redox function, can degrade and remove some organic matter; in addition, a large number of tiny bubbles generated by the cathode are small in size and large in specific surface area, and have a strong ability to adsorb and float suspended solids, colloids, and flocs with evacuated structures, which can improve the removal rate of organic matter by membrane technology and delay Membrane fouling increases the membrane cleaning cycle; the application of tubular ceramic microfiltration membrane can significantly improve the separation efficiency of solid and liquid after electrocoagulation treatment, save floor space and reduce energy consumption; at the same time, the physical, chemical and biological properties of tubular ceramic microfiltration membrane are stable , high mechanical strength, long service life, convenient storage, and easy backwashing; the combined process can adjust the scale of water purification and the quality of effluent water by increasing or decreasing the number of electrode plates and the number of ceramic microfiltration membranes to achieve engineering applications.

The technical solutions provided by the embodiments of the present invention have been introduced in detail above, and the principles and implementation modes of the embodiments of the present invention have been explained by using specific examples in this paper. The descriptions of the above embodiments are only applicable to help understand the embodiments of the present invention At the same time, for those of ordinary skill in the art, according to the embodiment of the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be construed as limiting the present invention.

Claims (5)

1. a kind of coupling device of electric flocculation ceramic micro filter film purifying slightly polluted water source water, including immersible pump (1), raw water box (2), Electric flocculation reactor intake pump (3), electric flocculation reactor (4), D.C. regulated power supply (5), intermediate water storage case (7), ceramic micro filter Membrane module intake pump (8), ceramic micro filter membrane module (9), backwash tank (10), filtered water tank (11), air compressor machine (12), condensed water Drain (15), condensed water return duct (16), concentration water pipe (17), infiltration water/backwash water conversion tube (18), backwash drain pipe (19) and air hose (20) it is characterised in that：The water inlet of described raw water box (2) is connected with immersible pump (1) by pipeline, water outlet Mouth is connected with electric flocculation reactor (4) through electric flocculation reactor intake pump (3), and described electric flocculation reactor (4) passes through wire (13) it is connected with D.C. regulated power supply (5), the water inlet phase of the outlet of this electric flocculation reactor (4) and intermediate water storage case (7) Logical, the outlet of intermediate water storage case (7) is connected with ceramic micro filter membrane module (9) through ceramic micro filter membrane module intake pump (8), in institute The bottom stating ceramic micro filter membrane module (9) is provided with the backwash drain pipe (19) being attached thereto, described ceramic micro filter membrane module (9) the concentration water pipe (17) on top is connected with condensed water drain (15) and condensed water return duct (16) by threeway, this concentration Water return duct (16) is connected with intermediate water storage case (7), and ceramic micro filter membrane module (9) outlet is via infiltration water/backwash water conversion Pipe (18) is communicated with backwash tank (10), and the outlet of described backwash tank (10) connects filtered water tank (11), sky is passed through in upper end Trachea (20) is connected with air compressor machine (12).

2. the coupling device of electric flocculation ceramic micro filter film purifying slightly polluted water source water according to claim 1, its feature exists In：Described electric flocculation reactor (4) includes battery lead plate (21), conductive copper rod (22), lucite shell (23) and is used for placing The bracket (24) of battery lead plate (21), this battery lead plate (21) passes through contact rod (22) and connects and parallel be staggered outside lucite In shell (23).

3. the coupling device of electric flocculation ceramic micro filter film purifying slightly polluted water source water according to claim 1 and 2, its feature It is：Described electric flocculation reactor (4) bottom is provided with base (6) and blow-off pipe (14).

4. the coupling device of electric flocculation ceramic micro filter film purifying slightly polluted water source water according to claim 1, its feature exists In：Described ceramic micro filter membrane module (9) adopts the intrinsic pressure ceramic micro filter film of tubular type.

5. a kind of technique with above-mentioned coupling device, is characterized in that, comprise the steps：

1) source water is through immersible pump (1) injection raw water box (2) more anti-by electric flocculation reactor intake pump (3) press-in electric flocculation Answer device (4), electric flocculation reactor intake pump (3) outlet is used for adjusting entering of electric flocculation reactor (4) equipped with valve and effusion meter The discharge constant time of staying for water body in 4L/min, and then control electric flocculation reactor (4) is 150s, electric flocculation reactor (4) it be arranged the thick pure aluminum plate of 8 pieces of 3mm in parallel as battery lead plate (21), the through hole that Φ 10 is opened in pole plate upper end passes through conductive copper rod (22) single stage type connects, and pole plate lower end is placed on bracket (24), polar plate spacing 10mm；

2) start D.C. regulated power supply (5), adjusting output current according to raw water quality makes electric current density in 0.5-3.0mA/cm²It Between float；

3) water processing through electric flocculation enters intermediate water storage case (7) under gravity, stops 300s to form small flco；

4) through step 3) reacted water body squeezes into ceramic micro filter membrane module (9) by ceramic micro filter membrane module intake pump (8), pottery Porcelain micro-filtration membrane module (9) adopts cross flow filter pattern, wherein the intrinsic pressure ceramic micro filter film of two (19) duct tubular types of filling, every film Long 500mm, is connected in series, Al₂O₃Material, membrane aperture 200nm, concentrate water section concentrated water drain (15) exclusion, partly lead to Cross condensed water return duct (16) and be back to intermediate water storage case (7), to make full use of unreacted metal ion, infiltration water enters Backwash tank (10) and filtered water tank (11), are 0.1MPa by Valve controlling transmembrane pressure on ceramic film component (9) water inlet pipe, Adjusting the Valve controlling reflux ratio concentrating on water pipe two branched pipe is 20%；

5) when the decay of this device aquifer yield is rapid, close ceramic micro filter membrane module intake pump (8) outlet and filtered water tank (11) enters Valve on water pipe, opens the valve on backwash drain pipe (19) and air hose (20), starts air compressor machine (12) backwash pottery Porcelain micro-filtration membrane, opens the mud that electric flocculation reactor (4) bottom excluded by blow-off pipe (14) simultaneously, and just exchanges battery lead plate (21) Negative pole.