CN111018057A

CN111018057A - Reductive oxidation electrochemical sewage treatment method

Info

Publication number: CN111018057A
Application number: CN202010006118.0A
Authority: CN
Inventors: 姜笔存; 谈政焱; 屈晋云; 宋均轲; 贺雨舟; 刘浩亮; 林加文; 高泽楠; 司徒瑜霞
Original assignee: Nanjing Innovation Centre For Environmental Protection Industry Co ltd
Current assignee: Nanjing Innovation Centre For Environmental Protection Industry Co ltd
Priority date: 2020-01-03
Filing date: 2020-01-03
Publication date: 2020-04-17
Anticipated expiration: 2040-01-03
Also published as: CN111018057B

Abstract

The invention discloses a reductive oxidation electrochemical sewage treatment method, and belongs to the field of sewage treatment. The first annular electrodes and the second annular electrodes are mutually nested and are alternately arranged, and a plurality of sewage treatment channels are formed between the annular electrodes; the first annular electrode and the second annular electrode are respectively communicated with an opposite power supply, sewage is baffled in a plurality of sewage treatment channels from inside to outside, and reduction and oxidation treatment is circularly carried out to effectively degrade organic matters which are difficult to treat in the sewage, so that the sewage treatment efficiency is improved; the method has the advantages of good treatment effect, simple operation, low treatment cost and the like.

Description

Reductive oxidation electrochemical sewage treatment method

Technical Field

The invention belongs to the field of sewage treatment, and particularly relates to a reductive oxidation electrochemical sewage treatment method.

Background

With the rapid development of the world economy, water pollution gradually becomes a worldwide problem. In the past decades, surface water and underground water in China are severely polluted by industrial production, agricultural activities, municipal sewage and the like. Particularly, with the increase of population, the demand of human beings for water is continuously increased, and how to effectively treat sewage and make the sewage reuse work is of great significance for realizing the sustainable development of economy and resources.

Conventional wastewater treatment methods in the prior art include mechanical treatment, physical methods, chemical methods, and biological methods. However, with the improvement of living standard and the continuous development of industrialization degree of people, the components of domestic sewage and industrial sewage are more and more complex, the types of organic matters possibly existing in the wastewater are more and more, and the difficulty of sewage treatment work is increased. Common organic pollutants in the sewage mainly comprise polycyclic aromatic hydrocarbons, nitrogen-containing organic compounds, halogenated hydrocarbons, heavy metal pollutants which cannot be degraded and other miscellaneous organic compounds, so that the conventional sewage treatment mode is difficult to meet the requirements on performance and effect.

The electrochemical treatment technology refers to a treatment method for removing harmful substances in sewage by utilizing electrical energy to generate chemical reaction. The electrochemical technology is widely applied to metal recovery, and the treatment of organic pollutants, suspended particles, various industrial wastewater and domestic wastewater to remove grease and other various wastewater. The electrochemical technology is favored by people due to the advantages of no secondary pollution, good treatment effect, low operation cost, easy operation and management and the like, and becomes a hot spot of current research.

Through retrieval, the invention patent application with the application publication number of CN103420451A and the application publication date of 2013, 12 and 4 discloses electrochemical multiple oxidation sewage treatment equipment, which comprises an outer ring battery system, a central battery system, a microporous conduit and a slag scraping device. Wherein, the central battery system electrode electrolyzes neutral solution to generate ozone, the outer ring battery system electrode electrolyzes water to generate hydroxyl self-assembly base, and the two can quickly oxidize organic matters which are difficult to degrade in water. However, the invention combines electrochemical decontamination and advanced oxidation decontamination to ensure the purification treatment of organic matters and the like in the sewage.

For another example, the invention patent application with application publication No. CN106430430A and publication date of 2017, 2 and 22 discloses an electrochemical sewage treatment system and a sewage treatment method thereof, wherein the electrochemical sewage treatment system is provided with a plurality of electrolysis units, each electrolysis unit comprises an anode, a cathode, a plurality of partition plates and an aeration device for providing exogenous oxygen for the cathode; the anode comprises a modified carbon paste electrode layer and a plurality of active metals arranged on the surface of the modified carbon paste electrode layer; the cathode and the spacer plate are both modified carbon paste electrodes; the active metal is pure iron. However, the modified carbon paste electrode is used as the electrode plate substrate, so that the conductivity, cyclic voltammetry and durability of the electrode plate are ensured well to improve the treatment effect, and the electrochemical sewage treatment system also comprises a biological membrane treatment unit, so that the treatment device has a complex structure, the treatment method is complicated, and the treatment cost is high. Disclosure of Invention

1. Problems to be solved

The invention provides a reductive oxidation electrochemical sewage treatment method, which comprises the steps of forming a plurality of nested sewage treatment channels by a cathode and an anode annular electrode, and baffling sewage from inside to outside in the plurality of sewage treatment channels to fully treat the sewage.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the invention relates to a reduction oxidation electrochemical sewage treatment method, which is characterized in that a first annular electrode and a second annular electrode are mutually nested and are alternately arranged, and a plurality of sewage treatment channels are formed between the annular electrodes; the first annular electrode and the second annular electrode are respectively communicated with an opposite power supply, sewage is baffled in the sewage treatment channels from inside to outside, and reduction oxidation treatment is carried out to degrade organic matters in the sewage.

Preferably, the total number of layers of the sewage treatment channels is 2n +1, wherein n is more than or equal to 1 and less than or equal to 4.

Preferably, the power supply mode of the power supply comprises one or more of constant current, pulse current and square wave current,

wherein: the pulse current A is a (sin (bt) + c), t is a time variable, unit second, a is an amplitude constant and is related to the water pollution degree, the conductivity and the electrode property, a ranges from 5 to 50, b is a frequency constant and is related to the pollutant property and the electrode bearing capacity, and b ranges from 0.01 to 500; c is an offset constant, and controls high-order current and low-order current, wherein the range of c is 0.5-1;

the square wave current a is (H, t1, L, t2, d), H is the high-order current, and the unit mA/cm²The range is generally 5-50, t1 is high time per second, L is low current per mA/cm²The range is generally-20 to 20, t2 is low-order time in unit of second, t2 is not more than t1, and d is space ratio, namely the gap time of high-order and low-order current switching in unit of second.

Preferably, the outer diameter ratio between two adjacent layers of sewage treatment channels is R_DWherein R is_DIn the range of 1.1-5.

Preferably, the current density applied to the sewage treatment channel is A_n＝kR_nAnd R is_n＝K_At_nn^0.5+Q_A，

Wherein: k is a reference current in the range of 1-50 mA/cm²；R_nIs the current density ratio between two adjacent channels, K_AIs an empirical constant, is related to the type of organic matter in the wastewater and the type of electrode used, and ranges from0.1～20；t_nIs a working condition constant, is related to the concentration of sewage pollutants and the flow rate of sewage, and ranges from 0.5 to 2.6, n is the number of channels, and Q_AThe range of the correction constant is-1 to 2.

Preferably, the reductive oxidation electrochemical sewage treatment method further comprises a reflux treatment step, wherein the reflux treatment mode comprises effluent reflux, middle reflux or a combination thereof.

Preferably, the effluent water refluxing specifically comprises the step of refluxing the effluent water of the outermost sewage treatment channel to the water inlet of the innermost sewage treatment channel for refluxing treatment; the middle part reflowing specifically comprises the step of reflowing the effluent of the outermost layer sewage treatment channel to the water inlet of a certain layer sewage treatment channel in the middle for reflowing treatment.

Preferably, the reflux ratio in the reflux treatment step is in the range of 50% to 400%.

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention relates to a reduction oxidation electrochemistry sewage treatment method, wherein a first annular electrode and a second annular electrode are mutually nested, the first annular electrode and the second annular electrode are alternately arranged, a sewage treatment channel is formed between the adjacent first annular electrode and the second annular electrode, and a plurality of layers of nested sewage treatment channels are formed among a plurality of annular electrodes; the first annular electrode and the second annular electrode are respectively communicated with an opposite power supply, sewage is baffled in the sewage treatment channels from inside to outside, reduction oxidation treatment is carried out to degrade organic matters in the sewage, and the sewage treatment efficiency and degree are improved;

(2) the invention relates to a method for treating electrochemical sewage by reduction and oxidation, wherein the total number of layers of sewage treatment channels arranged in a used device is 2n +1, wherein n is more than or equal to 1 and less than or equal to 4, a first annular electrode can be an anode, and a second annular electrode can be a cathode; or the first annular electrode may be a cathode and the second annular electrode an anode; when the first annular electrode is an anode and the second annular electrode is a cathode, the surface area of the second annular electrode in the current sewage treatment channel is larger than that of the first annular electrode, the area of the cathode is larger than that of the anode, a sewage treatment reaction area for strengthening reduction is formed, and the anode area is larger than that of the cathode after being baffled and enters the next sewage treatment channel, so that a sewage treatment reaction area for strengthening oxidation is formed; therefore, the sewage can be in the continuous cycle treatment process of reduction and oxidation, the organic matters in the sewage can be fully and effectively degraded, and the treatment effect is improved;

(3) the first annular electrode and the second annular electrode are used as a flow baffle plate and a reaction electrode, so that the reduction oxidation electrochemical sewage treatment device is simple in structure and low in manufacturing cost.

Drawings

FIG. 1 is a front view of an apparatus for electrochemical sewage treatment by redox in accordance with the present invention;

FIG. 2 is a left side view of an apparatus for electrochemical sewage treatment by redox according to the present invention;

FIG. 3 is a perspective view of an apparatus for electrochemical sewage treatment by redox in accordance with the present invention;

in the figure:

100. a device body; 110. a first sealing plate; 111. a first ring electrode;

120. a second sealing plate; 121. a second ring-shaped electrode; 130. a water inlet;

141. a first water outlet; 142. a second water outlet; 143. a third water outlet; 150. a return header pipe;

161. a first return port; 162. a second return port; 163. a third return port;

170. a water outlet pipe; 180. a three-way valve;

1101. a first protrusion; 1201. a second protrusion;

1611. a first return branch pipe; 1621. a second return leg; 1631. a third return manifold.

Detailed Description

For a further understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings and examples.

It will be understood by those skilled in the art that the foregoing and other changes, modifications, variations and alterations in the aspect of the invention may be made without departing from the spirit or scope of the invention as defined by the appended claims. Meanwhile, the terms such as "upper", "lower", "left", "right" and "middle" used in the present specification are for clarity of description only, and are not used to limit the implementable scope, and the relative relationship changes or adjustments may be considered to be within the implementable scope of the present invention without substantial technical changes; in addition, the embodiments of the present invention are not independent of each other, but may be combined.

As shown in fig. 1, the device for electrochemical sewage treatment by redox of the present invention comprises a device body 100, a first sealing plate 110 and a second sealing plate 120, wherein the first sealing plate 110 and the second sealing plate 120 are respectively disposed at the upper end and the lower end of the device body 100; the first sealing plate 110 is provided with a plurality of first annular electrodes 111 extending towards the second sealing plate 120, a gap is formed between the bottom end of the first sealing plate 110 and the second sealing plate 120, and the top of the first annular electrodes 111 protrudes out of the first sealing plate 110 to form a water inlet 130 for introducing sewage to be treated into the device body 100; the second sealing plate 120 is provided with a plurality of second ring electrodes 121 extending toward the first sealing plate 110, a gap is formed between the top ends of the second ring electrodes 121 and the first sealing plate 110, and the second sealing plate 120 is provided with a water outlet for discharging the treated sewage.

The first ring-shaped electrode 111 and the second ring-shaped electrode 121 are nested with each other, and the first ring-shaped electrode 111 and the second ring-shaped electrode 121 are alternately arranged; the first ring electrode 111 may be an anode and the second ring electrode 121 may be a cathode; or the first ring electrode 111 may be a cathode and the second ring electrode 121 may be an anode; a sewage treatment channel can be formed between the first annular electrode 111 and the second annular electrode 121, and the plurality of first annular electrodes 111 and the plurality of second annular electrodesA plurality of layers of nested sewage treatment channels can be formed between the electrodes 121, the total number of the sewage treatment channels is 2n +1, wherein n is more than or equal to 1 and less than or equal to 4, and the outer diameter ratio between two adjacent layers of sewage treatment channels is R_DWherein R is_DIn the range of 1.1-5.

In general, when sewage is treated by an electrocatalytic reaction, a part of the sewage is subjected to a catalytic reaction in a reactor, and a part of the sewage is subjected to a catalytic reaction on an electrode surface, and if the electrode surface area is larger, the catalytic reaction efficiency is higher, and if the catalytic speed is increased to a certain extent only by increasing the current density, a side reaction occurs due to an excessively high current, and the electrocatalytic efficiency is lowered. The device of the invention is provided with the anode and the cathode alternately in a nested way, so that a cylindrical baffling reactor is formed inside the device, the contact area between the sewage and the surface of the electrode is enlarged, the retention time of the sewage in the device is prolonged, and the sewage treatment efficiency is improved; further, since the surface areas of the inner and outer ring electrodes constituting the sewage treatment passage are different, an enhanced reduction/oxidation reaction region can be performed in each layer of the sewage treatment passage.

For example, two ring electrodes inside and outside the sewage treatment channel, that is, the adjacent first ring electrode 111 and second ring electrode 121, are formed as a layer of sewage treatment channel, for example, the inner ring electrode is an anode, the outer ring electrode is a cathode, the surface area of the outer ring electrode in the layer of sewage treatment channel is larger than that of the inner ring electrode, the area of the cathode is larger than that of the anode, a reaction region for enhancing reduction is formed in the sewage treatment channel, and the anode area is larger than that of the cathode when entering the next layer of sewage treatment channel after baffling, so that a reaction region for enhancing oxidation is formed; therefore, sewage introduced into the device can be in the cyclic treatment processes of reduction, oxidation, reduction and oxidation, organic matters which are difficult to treat are effectively degraded, and the sewage treatment efficiency is greatly improved.

It should be further noted that, as shown in fig. 3, the apparatus used in the method of the present invention has a first ring electrode and a second ring electrode, which can be used as both the reaction electrode and the current blocking function, so that the whole apparatus has a simple structure and is easy to manufacture.

Further, as shown in fig. 2, the first ring electrode 111 protrudes outward through the first seal plate 110, forming a first protrusion 1101; the second ring electrode 121 protrudes outwardly through the second seal plate 120 to form a second tab 1201, the first and

second tabs

1101, 1201 facilitating electrical connection to an external power source. It should be noted that such a structural arrangement allows applying different current densities to each of the plurality of first ring electrodes 111 and the plurality of second ring electrodes 121 during the treatment process to enhance the reactions in the different layers of wastewater treatment channels, as shown in the following formulas (1) and (2):

A_n＝kR_n(1)

R_n＝K_At_nn^0.5+Q_A(2)；

wherein k is a reference current and ranges from 1 to 50mA/cm²；R_nIs the current density ratio between two adjacent channels, K_AThe empirical constant is related to the types of organic matters in the sewage and the types of the used electrodes and ranges from 0.1 to 20; t is t_nIs a working condition constant, is related to the concentration of sewage pollutants and the flow rate of sewage, and ranges from 0.5 to 2.6, n is the number of channels, and Q_AThe range of the correction constant is-1 to 2.

The reduction oxidation electrochemical sewage treatment device used by the method also comprises a backflow port, wherein the backflow port is arranged on the first sealing plate 110 and is used for backflow of discharged effluent into the device for backflow treatment;

referring to fig. 1 again, the apparatus used in the method of the present invention includes, for example, seven layers of sewage treatment channels from inside to outside, the first sealing plate 110 is provided with a first return port 161, a second return port 162 and a third return port 163, the first return port 161 is located at the top of the third layer of sewage treatment channel, the second return port 162 is located at the top of the fifth layer of sewage treatment channel, and the third return port 163 is located at the top of the seventh layer of sewage treatment channel; the second sealing plate 120 is provided with a first water outlet 141, a second water outlet 142 and a third water outlet 143, the first water outlet 141 is positioned at the bottom of the fourth layer sewage treatment channel, the second water outlet 142 is positioned at the bottom of the sixth layer sewage treatment channel, and the third water outlet 143 is positioned at the bottom of the seventh layer sewage treatment channel;

it should be noted that a return manifold 150 is arranged between the first return port 161, the second return port 162, the third return port 163 and the third water outlet 143, and the return ports are all connected with the third water outlet 143 through the return manifold 150; the third water outlet 143 is further connected with the water outlet pipe 170, a three-way valve 180 is arranged at the intersection of the water outlet pipe 170 and the return header pipe 150, when the return treatment is not needed, the three-way valve 180 is rotated to a state that the water can be led to the water outlet pipe 170, and the sewage treated by the device is discharged from the water outlet pipe 170 through the third water outlet 143; when effluent water backflow treatment is needed, the three-way valve 180 is rotated to a state that the effluent water can be led to the backflow header pipe 150, sewage treated by the device flows back from the backflow header pipe 150 through the third water outlet 143 to enter any one of the first backflow port 161, the second backflow port 162 and the third backflow port 163, and then flows back into the device, and the backflow ratio is controlled to be within a range of 50% -400%.

Specifically, the return manifold 150 is provided with a first return branch 1611, a second return branch 1621 and a third return branch 1631, the first return port 161 is connected to the return manifold 150 through the first return branch 1611, the second return port 162 is connected to the return manifold 150 through the second return branch 1621, and the third return port 163 is connected to the return manifold 150 through the third return branch 1631, and the first return branch 1611, the second return branch 1621 and the third return branch 1631 are all provided with return control valves.

It should be noted that by controlling these backflow control valves, the position of the sewage treatment channel into which the effluent flows back can be controlled, that is, the backflow treatment mode is controlled, and the backflow treatment mode includes effluent backflow, middle backflow or a combination thereof.

For example, if it is desired to make the effluent from the third water outlet 143 enter the third layer sewage treatment channel for backflow treatment, the three-way valve 180 is rotated to open the backflow control valve of the first backflow branch 1611, and the backflow control valves of the second backflow branch 1621 and the third backflow branch 1631 are closed, so that the effluent flows back into the third layer sewage treatment channel through the first backflow port 161; the method can realize middle backflow of the effluent, namely backflow of the effluent of the outermost sewage treatment channel to the water inlet of a certain middle sewage treatment channel, so as to enhance the staged reduction and oxidation effects. For another example, when it is desired to return the effluent into the first-stage wastewater treatment channel, the effluent may be returned to the inlet 130 through a pipe (not shown) to return the effluent.

It should be noted that, in the electrochemical sewage treatment method by reduction and oxidation of the present invention, different power supply modes can be adopted for the first ring electrode and the second ring electrode of the used device, including one or more of constant current, pulse current and square wave current, wherein:

the pulse current A is a (sin (bt) + c), t is a time variable, unit second, a is an amplitude constant and is related to the water pollution degree, the conductivity and the electrode property, a ranges from 5 to 50, b is a frequency constant and is related to the pollutant property and the electrode bearing capacity, and b ranges from 0.01 to 500; c is an offset constant, and controls high-order current and low-order current, wherein the range of c is 0.5-1;

In general, when a constant current mode is used for treating specific sewage, electrode polarization is easy to generate, the current utilization rate is low, and the like.

Example 1

The electrochemical sewage treatment method of the embodiment is used for treating the pesticide wastewater with low toxicity and easy degradation, wherein the treatment device is usedThe sewage treatment channel has only 3 layers, and n is 1; the 1 st layer of electrode is an anode, the outer wall of the electrode is coated with a titanium substrate of anode material, the outer diameter is 32mm (the wall thickness is 2mm), R_D1-2＝R_D2-3The outer diameter of the cathode of the 2 nd layer is 50mm, and the outer diameter of the anode of the 3 rd layer is 100mm because the outer diameter is 1.5625.

Current density ratio R between two adjacent layers₂＝K_A2t_nn^0.5+Q_A2＝1*0.8*2^0.5+0＝1.13，R₃＝K_A3t_nn^0.5+Q_A3＝1*0.6*3^0.5+ 0-1.04, and a-20 (mA/cm) current²) Constant current, so that the current density of the layer 2 cathode is A₂＝AR₂＝22.6(mA/cm²) The current density of the layer 3 anode is A₃＝AR₃＝20.8(mA/cm²)。

Because the wastewater is easy to degrade and can be effectively degraded without backflow, the COD of the inlet water of the wastewater is about 1000-2000mg/L, and the removal rate of the COD after the treatment by the method of the embodiment is about 80-90%.

Example 2

The electrochemical sewage treatment method of the embodiment is used for treating chemical intermediate wastewater which needs strong reducing power, wherein a sewage treatment channel has 5 layers, and n is 2; the 1 st layer of electrode is an anode, the outer wall of the electrode is coated with a titanium substrate of anode material, the outer diameter is 20mm (the wall thickness is 1.5mm), R_D1-2＝5，R_D2-3＝1.2，R_D3-4＝1.27，R_D4-5Thus, the outer diameter of the cathode of the 2 nd layer is 100mm, the outer diameter of the anode of the 3 rd layer is 120mm, the outer diameter of the cathode of the 4 th layer is 190mm, and the outer diameter of the anode of the 5 th layer is 220 mm.

Current density ratio R between two adjacent layers₂＝K_At_nn^0.5+Q_A＝0.5*1.5*2^0.5+0.05＝1.11，R₃＝K_At_nn^0.5+Q_A＝0.5*0.5*3^0.5+0.05＝0.48，R₄＝K_At_nn^0.5+Q_A＝0.5*1.5*4^0.5+0.05＝1.55，R₅＝K_At_nn^0.5+Q_A＝0.5*0.5*5^0.5The current is (H, t1, L, t2, d) square wave current, the parameters of the square wave current H and L can be adjusted within a range according to the pollution load of the incoming water, t1 is adjusted within a range from 5s to 50s, t2 is about t1+5, and d is adjusted within a range from 5s to 150 s.

As the wastewater needs strong reduction action, independent backflow is arranged in the two reduction strengthening areas, namely backflow between the sewage treatment channels from the 1 st layer to the 2 nd layer and backflow between the sewage treatment channels from the 3 rd layer to the 4 th layer, the backflow ratio is 400 percent, the COD of the inflow water of the wastewater is about 7000-10000mg/L, the removal rate of the COD after the treatment by the method of the embodiment is about 50-65 percent, and the biodegradability of the outflow water is obviously improved.

Example 3

The electrochemical sewage treatment method by reduction and oxidation is used for treating chemical production wastewater which is extremely difficult to degrade and can be degraded only by long-time repeated reduction and oxidation. Wherein, the sewage treatment channel has 9 layers, and n is 4; the 1 st layer electrode is a cathode, the outer wall of the 1 st layer electrode is coated with a titanium substrate of cathode material, the outer diameter is 20mm (the wall thickness is 2mm), R_D1-2＝1.6，R_D2-3＝1.5625，R_D3-4＝1.5，R_D4-5＝1.6，R_D5-6＝1.25，R_D6-7＝1.23，R_D7-8＝1.13，R_D8-91.095, so the inside-out electrode size is 20, 32, 50, 75, 120, 150, 185, 210, 230 mm.

Current density ratio R between two adjacent layers₂＝K_A2t_nn^0.5+Q_A2＝0.2*2.6*2^0.5+0.2＝0.94，R₃＝0.2*2.2*3^0.5+0.2＝0.96，R₄＝0.2*2.6*4^0.5+0.2＝1.24，R₅＝0.2*2.2*5^0.5+0.2＝1.18，R₆＝0.2*2.6*6^0.5+0.2＝1.47，R₇＝0.2*2.2*7^0.5+0.2＝1.36，R₈＝0.2*2.6*8^0.5+0.2＝1.67，R₉＝0.2*2.2*9^0.5+0.2 ═ 1.52, pulse current a (mA/cm)²) A (sin (bt) + c), wherein a is adjusted in the range of 5-50, a between 1 st and 2 nd layers is 50 for preliminary enhanced oxidation, and the outermost layer is decreased to 5; bAdjusting the range of 0.1 to 500, wherein b between the 1 st layer and the 2 nd layer is 0.1, and the last layer is high-frequency pulse close to 500; c is adjustable within the range of 0.4-1, c between the 1 st layer and the 2 nd layer is 0.4, and the last layer is close to 1.

Because the wastewater is difficult to degrade and can be effectively degraded only by mixing and refluxing, 300 percent of reflux is applied to a lower-frequency intensified oxidation area between the sewage treatment channels from the layer 2 to the layer 4, 50 percent of reflux is applied to a high-frequency catalytic area between the sewage treatment channels from the layer 7 to the layer 9, and 100 percent of overall reflux is applied to effluent; the COD of the inlet water of the wastewater is higher, about 30000-60000mg/L, the water quality fluctuation is larger, the COD removal rate after the treatment by the method of the embodiment is about 60-80%, and the biodegradability of the outlet water is greatly improved.

The invention has been described in detail hereinabove with reference to specific exemplary embodiments thereof. It will, however, be understood that various modifications and changes may be made without departing from the scope of the invention as defined in the appended claims. The detailed description and drawings are to be regarded as illustrative rather than restrictive, and any such modifications and variations are intended to be included within the scope of the present invention as described herein. Furthermore, the background is intended to be illustrative of the state of the art as developed and the meaning of the present technology and is not intended to limit the scope of the invention or the application and field of application of the invention.

Claims

1. A reduction oxidation electrochemical sewage treatment method is characterized in that: nesting a first annular electrode and a second annular electrode, wherein the first annular electrode and the second annular electrode are alternately arranged, and a plurality of sewage treatment channels are formed between the annular electrodes; the first annular electrode and the second annular electrode are respectively communicated with an opposite power supply, sewage is baffled in the sewage treatment channels from inside to outside, and reduction oxidation treatment is carried out to degrade organic matters in the sewage.

2. The electrochemical sewage treatment method for reduction and oxidation according to claim 1, wherein: the total number of layers of the sewage treatment channels is 2n +1, wherein n is more than or equal to 1 and less than or equal to 4.

3. The electrochemical sewage treatment method for reduction and oxidation according to claim 1, wherein: the power supply mode of the power supply comprises one or more of constant current, pulse current and square wave current,

4. The electrochemical sewage treatment method for reduction and oxidation according to claim 2, wherein: the outer diameter ratio between two adjacent layers of sewage treatment channels is R_DWherein R is_DIn the range of 1.1-5.

5. The electrochemical sewage treatment method for reduction and oxidation according to claim 2, wherein: the current density applied to the sewage treatment channel is A_n＝kR_nAnd R is_n＝K_At_nn^0.5+Q_A，

Wherein: k is a reference current in the range of 1-50 mA/cm²；R_nIs the current density ratio between two adjacent channels, K_AThe empirical constant is related to the types of organic matters in the sewage and the types of the used electrodes and ranges from 0.1 to 20; t is t_nIs a working condition constant, is related to the concentration of sewage pollutants and the flow rate of sewage, and ranges from 0.5 to 2.6, n is the number of channels, and Q_ATo correct the constantA number in the range of-1 to 2.

6. The electrochemical sewage treatment method for reduction and oxidation according to claim 2, wherein: the method also comprises a reflux treatment step, wherein the reflux treatment mode comprises effluent reflux, middle reflux or a combination thereof.

7. The electrochemical sewage treatment method for reduction and oxidation according to claim 6, wherein: the effluent water backflow method comprises the specific steps that effluent water of the outermost sewage treatment channel flows back to the water inlet of the innermost sewage treatment channel for backflow treatment; the middle part reflowing specifically comprises the step of reflowing the effluent of the outermost layer sewage treatment channel to the water inlet of a certain layer sewage treatment channel in the middle for reflowing treatment.

8. The electrochemical sewage treatment method for reduction and oxidation according to claim 6, wherein: the reflux ratio in the reflux treatment step is between 0 and 400 percent.