1. The utility model provides a step electrochemistry is reinforceed multicycle denitrogenation and is removed carbon bioreactor which characterized in that: the device comprises a reactor body (100), wherein a first gas-liquid separator (110), a second gas-liquid separator (120) and a third gas-liquid separator (130) are arranged at the top of the reactor body (100), a water distributor (200) is arranged at the bottom of the reactor body (100), and a first-stage electrochemical enhancement zone (300), a first microbial treatment zone (400), a second-stage electrochemical enhancement zone (500), a second microbial treatment zone (600) and a sludge settling zone (700) are sequentially arranged in the reactor body (100) from bottom to top;

wherein, a first-stage electrochemical enhancement area (300) is arranged above the water distributor (200), a gas collector (800) is arranged between the first-stage electrochemical enhancement area (300) and the first microorganism processing area (400), a first-stage three-phase separator (900) is arranged between the first microorganism processing area (400) and the second-stage electrochemical enhancement area (500), a second-stage three-phase separator (910) is arranged between the second microorganism processing area (600) and the sludge settling area (700), a first lifting pipe (810) is arranged on the gas collector (800), the gas collector (800) is connected with the first gas-liquid separator (110) through the first lifting pipe (810), a second lifting pipe (920) is arranged on the first-stage three-phase separator (900), the first-stage three-phase separator (900) is connected with the second gas-liquid separator (120) through the second lifting pipe (920), a third lifting pipe (930) is arranged on the second-stage three-phase separator (910), the second-stage three-phase separator (910) is connected with a third gas-liquid separator (130) through a third riser (930); and is

Wherein, the first gas-liquid separator (110), the second gas-liquid separator (120) and the third gas-liquid separator (130) are correspondingly provided with a first downcomer (811), a second downcomer (921) and a third downcomer (931), the first downcomer (811) extends downwards to the water distributor (200), the second downcomer (921) extends downwards to the first microorganism treatment area (400), and the third downcomer (931) extends downwards to the second microorganism treatment area (600).

2. The utility model provides a step electrochemistry is reinforceed multicycle denitrogenation and is removed carbon bioreactor which characterized in that: a first circulation inlet (610) is formed in the side wall of the reactor body of the sludge settling zone (700), a first circulation outlet (620) is formed in the side wall of the reactor body of the second microorganism treatment zone (600), and the first circulation inlet (610) is connected with the first circulation outlet (620) through a first circulation pipeline (630);

a second circulation inlet (710) is arranged on the side wall of the reactor body between the secondary electrochemical enhancement area (500) and the primary three-phase separator (900), a second circulation outlet (720) is arranged on the side wall of the reactor body of the first microbial treatment area (400), and the second circulation inlet (710) is connected with the second circulation outlet (720) through a second circulation pipeline (730).

3. The cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor as claimed in claim 1, wherein: the volume ratio between the primary electrochemical enhancement zone (300) and the secondary electrochemical enhancement zone (500) is (1-2): 1; the volume ratio between the first microbial treatment area (400) and the second microbial treatment area (600) is (1-1.5): 1.

4. the cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor as claimed in claim 1, wherein: the gas collector (800) comprises a plurality of gas collecting hoods (8100), the gas collecting hoods (8100) are arranged in a staggered mode at intervals up and down, the distance D1 between the gas collecting hood (8100) on the upper layer and the gas collecting hood (8100) on the lower layer is 10-20 cm, and the distance D2 between the gas collecting hoods (8100) on the same layer is 10-20 cm; and the shape of the gas collecting hood (8100) is an inverted V shape, and the top of the V shape is a circular structure with the radius of 1/3 cm.

5. The cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor as claimed in claim 1, wherein: a plurality of polar plates (8200) are arranged in the primary electrochemical enhancement region (300) and the secondary electrochemical enhancement region (500), the plurality of polar plates (8200) are arranged in a staggered mode at intervals from top to bottom, the number of the polar plate layers in the primary electrochemical enhancement region (300) is a, the number of the polar plate layers in the secondary electrochemical enhancement region (500) is b, the value range of a is an odd number in the range of 3-9, and b is a/2+ 1.5.

6. The cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor as claimed in claim 5, wherein: the distance between the polar plate at the bottommost layer in the primary electrochemical enhancement region (300) and the top of the water distributor (200) is 300-500 mm; and/or the distance between the bottom polar plate in the secondary electrochemical enhancement area (500) and the top of the primary three-phase separator (900) is 500-700 mm.

7. The cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor as claimed in claim 5, wherein: the shape of the polar plate (8200) is an inverted V shape, and the included angle of the inverted V shape is 50-60 degrees.

8. The cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor as claimed in claim 5, wherein: a plurality of holes are distributed on the polar plate (8200), the diameter of each hole is 2-4 cm, and the distance between every two holes is 8-10 cm.

9. A sewage denitrification and carbon removal treatment process is characterized in that: the adoption of the cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor of any one of claims 1 to 8 comprises the following specific process steps:

s10, enabling the sewage to enter the reactor body from the water distributor, performing electric flocculation, reduction and oxidation reactions in the primary electrochemical enhancement zone to remove heavy metal ions and generate oxygen and hydrogen, dissolving the generated oxygen in the sewage to provide an anoxic denitrification environment, and collecting the generated hydrogen through a gas collector;

s20, enabling the effluent treated by the primary electrochemical enhancement area to enter a first microbial treatment area, performing denitrification and denitrification treatment on the lower part of the first microbial treatment area, performing carbon removal treatment on the middle part and the upper part of the first microbial treatment area, generating nitrogen and methane, and collecting and separating the generated nitrogen and methane through a primary three-phase separator;

s30, enabling the effluent treated in the first microorganism treatment area to enter a secondary electrochemical enhancement area for electrocoagulation, reduction and oxidation reactions to generate oxygen and hydrogen, dissolving the generated oxygen in the sewage to provide an anoxic denitrification environment, and collecting the generated hydrogen through a secondary three-phase separator;

s40, enabling the effluent treated by the secondary electrochemical enhancement area to enter a second microbial treatment area, performing denitrification treatment on the lower part of the second microbial treatment area, performing decarbonization treatment on the middle part and the upper part of the second microbial treatment area to generate nitrogen and methane, and collecting the generated nitrogen and methane through a secondary three-phase separator;

s50, the effluent treated in the second microorganism treatment area enters a sludge precipitation area, and the effluent after sludge precipitation is discharged through an overflow weir;

the gas collector collects hydrogen generated in the primary electrochemical enhancement area, gas-carried sewage enters a first gas-liquid separator through a first lifting pipe, gas and sewage are separated in the first gas-liquid separator, and then the sewage enters the upper part of the water distributor through a first descending pipe; nitrogen and methane generated in the first microorganism treatment area are collected through a first-stage three-phase separator, gas-carried sewage enters a second gas-liquid separator through a second lifting pipe, gas and sewage are separated in the second gas-liquid separator, and the sewage enters the upper part of a first-stage electrochemical enhancement area through a second descending pipe; and the nitrogen and methane generated in the second microorganism treatment area are collected by a second three-phase separator, the gas carried sewage enters a third gas-liquid separator through a third lifting pipe, the gas and the sewage are separated in the third gas-liquid separator, and the sewage enters the upper part of the second electrochemical enhancement area through a third descending pipe to form triple internal circulation treatment.

10. The process of claim 9, wherein the denitrification and decarbonization treatment is carried out by: s70, circulating the sewage at the bottom of the sludge settling zone to the upper part of the secondary electrochemical enhancement zone through a first circulating pipeline; and the sewage at the bottom of the secondary electrochemical enhancement area is circulated to the upper part of the gas collector through a second circulation pipeline to form double external circulation treatment.

Background

The industrial wastewater has the characteristics of unstable water quantity, high organic matter concentration, strong biological toxicity and the like. The industrial wastewater treatment usually adopts an anaerobic reactor as a core and is assisted by processes such as acid-base regulation, coagulating sedimentation, pre-acidification, aerobic treatment and the like.

However, the treatment process and anaerobic reactor have the following disadvantages: (1) the operation performance is poor, liquid alkali or lime is usually required to be added in the acid-base adjusting process, the preparation is required in the operation process, the operation is complex, and the working environment is poor; the water temperature is low in winter, the running effect of the anaerobic reactor is poor, a preposed steam heating system is often needed to improve the water temperature, the energy utilization rate is low, and the control precision is low. (2) The anaerobic reactor has weak impact resistance and unstable treatment effect. The anaerobic reactor mainly depends on microbial metabolism to remove pollutants, and if the chemical wastewater has strong biological toxicity and poor self-regulation energy-saving performance, a system is easy to collapse, and the recovery period is long; the chemical wastewater usually contains sulfate ions and the like, generates hydrogen sulfide under the action of sulfate reducing bacteria, has an inhibiting effect on methanogens, and simultaneously competes with the methanogens for nutrition, so that the organic matter removing performance of the anaerobic reactor is reduced. (3) The regulation and control scope is small, and the reactor is slow to start. Anaerobic reactors are generally designed and installed according to set concentration, the treatment capacity is fixed after the size is determined, and when the water inlet load is increased, the water outlet concentration is correspondingly increased; the chemical wastewater has strong biological toxicity, the microbial activity is inhibited, long-term domestication is needed, and the start period is long. (4) The removal index is single. COD is got rid of in the important consideration of traditional anaerobic reactor, and anaerobic reactor only sets up an inner loop downcomer usually, and the downcomer is finally delivered to the water distribution system of reactor bottom with sewage and mud, leads to the existence of the various dominant bacteria of unable realization co-altitude in the reactor, and traditional anaerobic reactor gets rid of the effect difference to total nitrogen etc..

The research shows that the application No. 201811414347.5, filed 2018, 11 and 26 discloses a high-efficiency anaerobic denitrification bioreactor, the side wall of a tank body of the bioreactor is provided with a water outlet, the interior of the tank body is divided into five functional areas including a mixing area, a denitrification and decarbonization chamber, a decarbonization conversion chamber, a precipitation area and a gas-water separation area, part of difficultly-degradable substances in water can be converted into biodegradable organic matters while denitrification and decarbonization are carried out by integrating the two processes of denitrification and decarbonization, and after a large amount of circulating water and inlet water are fully mixed by adopting a forced large-circulation backflow mode, harmful factors of nitrate nitrogen and the like in raw water on methanogenic bacteria, denitrifying bacteria and the like are fully diluted, the influence of poisons on the anaerobic denitrification process is greatly reduced, and the impact load resistance of the bioreactor is high. However, the reactor still has the problems of poor removal effect and single removal index, and only can remove a part of COD.

Disclosure of Invention

1. Problems to be solved

Aiming at the problems of weak impact resistance, poor removal effect, single removal index and the like of a wastewater treatment reactor and a process thereof in the prior art, the invention provides a cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor and a process thereof. According to the invention, through the optimization design of the cascade electrochemical module and the independent design of the triple internal circulation system, a two-stage anoxic-anaerobic environment is established, and the synchronous removal of total nitrogen and COD is realized.

2. Technical scheme

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

the invention discloses a stepped electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor, which comprises a reactor body, wherein the top of the reactor body is provided with a first gas-liquid separator, a second gas-liquid separator and a third gas-liquid separator;

the device comprises a primary electrochemical enhancement area, a first microbial treatment area, a second microbial treatment area, a sludge settling area, a first gas collector, a first riser, a second riser, a third riser, a second gas-liquid separator, a third riser and a third gas-liquid separator, wherein the primary electrochemical enhancement area is arranged above a water distributor, the gas collector is arranged between the primary electrochemical enhancement area and the first microbial treatment area, the first three-phase separator is arranged between the first microbial treatment area and the second electrochemical enhancement area, the second three-phase separator is arranged between the second microbial treatment area and the sludge settling area, the gas collector is provided with the first riser, the gas collector is connected with the first gas-liquid separator through the first riser, the second riser is arranged on the first three-phase separator, the first three-; and is

The first gas-liquid separator, the second gas-liquid separator and the third gas-liquid separator are correspondingly provided with a first downcomer, a second downcomer and a third downcomer, the first downcomer extends downwards to the water distributor, the second downcomer extends downwards to the first microorganism treatment area, and the third downcomer extends downwards to the second microorganism treatment area.

Preferably, a first circulation inlet is formed in the side wall of the reactor body of the sludge settling zone, a first circulation outlet is formed in the side wall of the reactor body of the second microorganism treatment zone, and the first circulation inlet is connected with the first circulation outlet through a first circulation pipeline;

and a second circulation inlet is formed in the side wall of the reactor body between the secondary electrochemical enhancement area and the primary three-phase separator, a second circulation outlet is formed in the side wall of the reactor body of the first microbial treatment area, and the second circulation inlet is connected with the second circulation outlet through a second circulation pipeline.

Preferably, the volume ratio of the primary electrochemical enhancement zone to the secondary electrochemical enhancement zone is (1-2): 1; the volume ratio between the first microbial treatment area and the second microbial treatment area is (1-1.5): 1.

more preferably, the primary and secondary electrochemical enhancement zones account for 25% of the total volume of the reactor body, the first and second microbial treatment zones account for 65% of the total volume of the reactor body, and the sludge settling zone accounts for 10% of the total volume of the reactor body.

Preferably, the gas collector comprises a plurality of gas collecting hoods which are arranged in a staggered manner at intervals from top to bottom, the distance D1 between the gas collecting hoods on the upper layer and the gas collecting hoods on the lower layer is 10-20 cm, and the distance D2 between the gas collecting hoods on the same layer is 10-20 cm; and the shape of the gas collecting hood is an inverted V-shaped structure, and the top of the V-shaped structure is 1/3 circular structure with the radius of 3 cm.

More preferably, the gas collector further comprises a gas relay, and the gas collecting hood is vertically connected with the gas relay in a horizontal direction through welding.

Preferably, a plurality of polar plates are arranged in the primary electrochemical enhancement region and the secondary electrochemical enhancement region, the plurality of polar plates are arranged in a staggered manner at intervals from top to bottom, the number of polar plate layers in the primary electrochemical enhancement region is a, the number of polar plate layers in the secondary electrochemical enhancement region is b, the value range of a is an odd number in a range of 3-9, the value range of b is 3-6, and b is a/2+ 1.5.

Preferably, the distance between the bottom polar plate in the primary electrochemical enhancement area and the top of the water distributor is 300-500 mm; and/or the distance between the bottom polar plate in the secondary electrochemical enhancement area and the top of the primary three-phase separator is 500-700 mm.

Preferably, the shape of the polar plate is an inverted V shape, and the included angle of the inverted V shape is 50-60 degrees.

Preferably, a plurality of holes are distributed on the polar plate, the diameter of each hole is 2-4 cm, and the distance between the two holes is 8-10 cm.

More preferably, the polar plate is one or more of an aluminum plate, an iron plate, a titanium plate, a graphite plate, stainless steel and boron-doped diamond.

The invention relates to a sewage denitrification and decarbonization treatment process, which adopts the stepped electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor and comprises the following specific process steps:

s10, enabling the sewage to enter the reactor body from the water distributor, performing electric flocculation, reduction and oxidation reactions in the primary electrochemical enhancement zone to remove heavy metal ions and generate oxygen and hydrogen, dissolving the generated oxygen in the sewage to provide an anoxic denitrification environment, and collecting the generated hydrogen through a gas collector;

s20, enabling the effluent treated by the primary electrochemical enhancement area to enter a first microbial treatment area, performing denitrification and denitrification treatment on the lower part of the first microbial treatment area, performing carbon removal treatment on the middle part and the upper part of the first microbial treatment area, generating nitrogen and methane, and collecting and separating the generated nitrogen and methane through a primary three-phase separator;

s30, enabling the effluent treated in the first microorganism treatment area to enter a secondary electrochemical enhancement area for electrocoagulation, reduction and oxidation reactions to generate oxygen and hydrogen, dissolving the generated oxygen in the sewage to provide an anoxic denitrification environment, and collecting the generated hydrogen through a secondary three-phase separator;

s40, enabling the effluent treated by the secondary electrochemical enhancement area to enter a second microbial treatment area, performing denitrification treatment on the lower part of the second microbial treatment area, performing decarbonization treatment on the middle part and the upper part of the second microbial treatment area to generate nitrogen and methane, and collecting the generated nitrogen and methane through a secondary three-phase separator;

s50, the effluent treated in the second microorganism treatment area enters a sludge precipitation area, and the effluent after sludge precipitation is discharged through an overflow weir;

the gas collector collects hydrogen generated in the primary electrochemical enhancement area, gas-carried sewage enters a first gas-liquid separator through a first lifting pipe, gas and sewage are separated in the first gas-liquid separator, and then the sewage enters the upper part of the water distributor through a first descending pipe; nitrogen and methane generated in the first microorganism treatment area are collected through a first-stage three-phase separator, gas-carried sewage enters a second gas-liquid separator through a second lifting pipe, gas and sewage are separated in the second gas-liquid separator, and the sewage enters the upper part of a first-stage electrochemical enhancement area through a second descending pipe; and the nitrogen and methane generated in the second microorganism treatment area are collected by a second three-phase separator, the gas carried sewage enters a third gas-liquid separator through a third lifting pipe, the gas and the sewage are separated in the third gas-liquid separator, and the sewage enters the upper part of the second electrochemical enhancement area through a third descending pipe to form triple internal circulation treatment.

Preferably, the process for denitrification and decarbonization of sewage further comprises step S70, circulating the sewage at the bottom of the sludge settling zone to the upper part of the secondary electrochemical enhancement zone through the first circulation pipeline; and the sewage at the bottom of the secondary electrochemical enhancement area is circulated to the upper part of the gas collector through a second circulation pipeline to form double external circulation treatment.

3. Advantageous effects

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

(1) the cascade electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor comprises a primary electrochemical enhancement area and a secondary electrochemical enhancement area which are designed in a cascade optimization manner, is used for treating sewage with different pollutant concentrations, and can effectively reduce the harmful pollutant concentration, weaken the biotoxicity, increase the microbial activity, improve the impact resistance and stabilize the treatment effect;

(2) according to the gradient electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor, multiple internal circulation systems are independently designed, so that culture of dominant floras at different heights is realized, and the removal efficiency of the whole treatment process is higher;

(3) according to the process for denitrification and decarbonization of sewage, oxygen is generated in the operation process of the primary electrochemical enhancement area and the secondary electrochemical enhancement area, the dissolved oxygen concentration can be controlled to be 0.2-0.5 mg/L as the oxygen is dissolved in water, an anoxic-anaerobic-anoxic-anaerobic environment is formed in the reactor from bottom to top, and the total nitrogen and COD are synchronously removed by building the two-stage anoxic-anaerobic environment.

Drawings

FIG. 1 is a schematic structural diagram of a stepped electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor of the present invention;

FIG. 2 is a schematic view of the gas collector of the present invention;

FIG. 3 is a schematic diagram of the structure of a plate in a primary or secondary electrochemical enhancement zone of the present invention;

FIG. 4 is a right side view of the plate of the present invention;

in the figure:

100. a reactor body; 110. a first gas-liquid separator; 120. a second gas-liquid separator;

130. a third gas-liquid separator; 200. a water distributor; 300. a primary electrochemical enhancement zone;

400. a first microbial treatment zone; 500. a secondary electrochemical enhancement zone; 600. a second microbial treatment zone;

610. a first circulation inlet; 620. a first recycle outlet; 630. a first circulation line;

700. a sludge settling zone; 710. a second circulation inlet; 720. a second recycle outlet;

730. a second circulation line; 800. a gas collector; 810. a first riser;

811. a first downcomer; 900. a first-stage three-phase separator; 910. a secondary three-phase separator;

920. a second riser; 930. a third riser; 921. a second downcomer;

931. a third downcomer; 8100. a gas-collecting hood; 8200. and (4) a polar plate.

Detailed Description

The invention is further described with reference to specific examples.

As shown in FIG. 1, the reactor of the present invention can be a cylindrical tank with a diameter of 6-14 m, a height of 18-24 m, and a height-diameter ratio of (2-3): 1, the reactor material is steel.

The top of the reactor body 100 is provided with a first gas-liquid separator 110, a second gas-liquid separator 120 and a third gas-liquid separator 130, the bottom of the reactor body 100 is provided with a water distributor 200, and the inside of the reactor body 100 is sequentially provided with a primary electrochemical enhancement area 300, a gas collector 800, a first microorganism treatment area 400, a primary three-phase separator 900, a secondary electrochemical enhancement area 500, a second microorganism treatment area 600, a secondary three-phase separator 910 and a sludge settling area 700 from bottom to top;

the gas collector 800 is provided with a first lifting pipe 810, the gas collector 800 is connected with the first gas-liquid separator 110 through the first lifting pipe 810, the first-stage three-phase separator 900 is provided with a second lifting pipe 920, the first-stage three-phase separator 900 is connected with the second gas-liquid separator 120 through the second lifting pipe 920, the second-stage three-phase separator 910 is provided with a third lifting pipe 930, and the second-stage three-phase separator 910 is connected with the third gas-liquid separator 130 through the third lifting pipe 930;

the first gas-liquid separator 110, the second gas-liquid separator 120 and the third gas-liquid separator 130 are correspondingly provided with a first downcomer 811, a second downcomer 921 and a third downcomer 931, the first downcomer 811 extends downwards to the water distributor 200, and the lowest point of the first downcomer 811 is at the same height as the water distributor 200; the second downcomer 921 extends downwards to the first microorganism processing zone 400, and the lowest point of the second downcomer 921 is 500-1000 mm at the top of the gas collector 800; the third downcomer 931 extends downward to the second microorganism treatment zone 600, and the lowest point of the third downcomer 931 is located at the top of the first-stage three-phase separator 900 by 500-1000 mm.

It should be noted that the primary electrochemical enhancement zone 300 and the secondary electrochemical enhancement zone 500 occupy 15 to 25%, preferably 25%, of the total volume of the reactor body 100; the volume ratio between the primary electrochemical enhancement zone 300 and the secondary electrochemical enhancement zone 500 is (1-2): 1; the first microorganism processing area 400 accounts for 35-45% of the total volume of the reactor body 100, the second microorganism processing area 600 accounts for 20-30% of the total volume of the reactor body 100, and preferably, the volume ratio between the first microorganism processing area 400 and the second microorganism processing area 600 is (1-1.5): 1; and the sludge settling zone 700 accounts for 10% of the total volume of the reactor body 100.

It should be further noted that, as shown in fig. 2, the gas collector 800 includes gas collecting hoods 8100 and a gas relay device (not shown), the gas collecting hoods 8100 are arranged in a staggered manner at intervals from top to bottom, usually, the number of the gas collecting hoods 8100 is 2 to 4, a distance D1 between an upper layer of gas collecting hoods 8100 and a lower layer of gas collecting hoods 8100 is 10 to 20cm, and a distance D2 between gas collecting hoods 8100 of the same layer is 10 to 20 cm.

The shape of the gas collecting hood 8100 is an inverted V shape, and the top of the V shape is a circular structure with the radius of 1/3 cm. The length of the single gas-collecting hood is 2-3 m, the width of a single side is 30-40 cm, and the thickness is 3 mm. The inverted V-shaped elliptical design has high contact ratio of the upper and lower polar plates and high collection efficiency of methane, hydrogen, nitrogen and the like carried in sewage.

In addition, a plurality of polar plates 8200 are arranged in the primary electrochemical enhancement region 300 and the secondary electrochemical enhancement region 500, the plurality of polar plates 8200 are arranged in a staggered mode at intervals from top to bottom, the number of the polar plate layers in the primary electrochemical enhancement region 300 is a, the number of the polar plate layers in the secondary electrochemical enhancement region 500 is b, the value range of a is an odd number in the range of 3-9, the value range of b is 3-6, and b is a/2+ 1.5.

The polar plate material can be aluminum plate, iron plate, graphite plate, stainless steel, boron-doped diamond, titanium plate or the like. The distance between the bottom polar plate in the primary electrochemical enhancement area 300 and the top of the water distributor 200 is 300-500 mm, and the distance between the bottom polar plate in the secondary electrochemical enhancement area 500 and the top of the primary three-phase separator 900 is 500-700 mm. As shown in FIG. 3, the distance between the left and right polar plates is 10-20 cm, the distance between the upper and lower polar plates is 10-20 cm, and the upper and lower polar plates are arranged in a crossed manner. Such design helps improving the contact probability of sewage and polar plate, helps stabilizing rivers simultaneously, prevents that sewage from flowing for a short time.

As shown in figure 4, the pole plate 8200 is inverted V-shaped, the length of a single pole plate is 0.8-1.2 m, the width of a single side is 0.3-0.4 m, the thickness is 1-5 mm, the included angle of the inverted V-shaped is 50-60 degrees, a plurality of circular holes are distributed on the pole plate 8200, the diameter of each circular hole is 2-4 cm, and the distance between the two holes is 8-10 cm. The polar plates are connected by welding, binding posts are arranged on the same height of the inverted V-shaped top points of the polar plates, and the polar plates are connected with each other by cables. The current density, the electrifying time and the electrifying mode of the polar plate are adjusted in real time according to the concentration of the inlet water such as pH, COD, sulfate radicals, temperature and the like, and the basic current density is 50mA/cm²The density range is 50-300 mA/cm²。

The invention relates to a cascade electrochemical enhanced multi-cycle denitrification and carbon removal bioreactor, which also comprises two independent external circulation systems. A first circulation inlet 610 is formed in the side wall of the reactor body of the sludge settling zone 700, a first circulation outlet 620 is formed in the side wall of the reactor body of the second microorganism treatment zone 600, and the first circulation inlet 610 is connected with the first circulation outlet 620 through a first circulation pipeline 630; a second circulation inlet 710 is arranged on the side wall of the reactor body between the secondary electrochemical enhancement zone 500 and the primary three-phase separator 900, a second circulation outlet 720 is arranged on the side wall of the reactor body of the first microbial treatment zone 400, and the second circulation inlet 710 is connected with the second circulation outlet 720 through a second circulation pipeline 730.

The stepped electrochemical enhanced multi-cycle denitrification and decarbonization bioreactor disclosed by the invention is adopted for carrying out denitrification and decarbonization treatment on sewage, the reaction pH value in a primary electrochemical enhancement area 300 is controlled to be 4.5-5.5, the dissolved oxygen is 0.2-0.5 mg/L, the sludge concentration is 5000-6000 mg/L, the reaction temperature is 25-30 ℃, and the current density range is 50-300 mA/cm²；

The sludge concentration MLSS of the first microorganism treatment area 400 is controlled to be 8000-10000 mg/L, the reaction temperature is 25-30 ℃, the pH value of inlet water is 6-8, and the rising flow velocity is V₁Controlling the reflux amount Q to be 2-6 m/h₁Is 0.785D²V₁0.42C, wherein the upward flow velocity V₁(m/h), reactor diameter D (m), water inflow Q (m)³H), the COD concentration C (g/L) of the inlet water;

the dissolved oxygen of the secondary electrochemical enhancement region 500 is 0.2-0.5 mg/L, the reaction temperature is 25-30 ℃, and the current density range is 50-200 mA/cm²(ii) a The sludge concentration of the second microorganism treatment area 600 is 4000-5000 mg/L, the reaction temperature is 25-30 ℃, the pH value of inlet water is 6-8, and the rising flow velocity V is₂Controlling the reflux amount Q to be 2-3 m/h₂Is 0.785D²V₂0.105C, where the upward flow velocity is V₂. The method comprises the following specific steps:

s10, sewage enters the water distributor through the pump, the effluent of the water distributor passes through the primary electrochemical enhancement area 300, and under the action of the introduced current, the purposes of pH regulation, heavy metal flocculation precipitation removal, biodegradability improvement and the like are achieved through the actions of electric flocculation, electrocatalysis and the like. The generated oxygen is dissolved in the sewage to provide an anoxic denitrification environment; the hydrogen generated by the electrode, the nitrogen generated by denitrification and the methane generated by methanogenic bacteria are enriched in the gas collector, enter the first gas-liquid separator 110 at the top of the reactor body to realize the separation of gas and sewage, the gas enters the combustion system, and the sewage enters the water distributor area again through the first downcomer.

S20, the effluent treated by the primary electrochemical enhancement area enters a first microbial treatment area, the sludge concentration of the first microbial treatment area is high, the bottom of the first microbial treatment area is in an anoxic environment, and the middle upper part of the first microbial treatment area is in an anaerobic environment. At the bottom of the first microorganism processing area, nitrate nitrogen in the sewage is converted into nitrogen through the action of denitrifying bacteria, and at the upper part of the first microorganism processing area, organic matters in the sewage are removed through the action of methanogen. Methane, nitrogen and the like generated in the reaction process pass through a first-stage three-phase separator and enter a second gas-liquid separator with an independent top, gas such as methane and the like enter a methane treatment system, and the rest sludge in the sewage is separated and enters the bottom of a first microorganism treatment area; meanwhile, a second circulation inlet is formed in the upper portion of the first-stage three-phase separator in the first microbial treatment area, a second circulation outlet is formed in the upper portion of the topmost pole plate in the first-stage electrochemical enhancement area, and the sludge suspension state is achieved through flow control of an external pump.

S30, enabling the effluent treated in the first microorganism treatment area to enter a secondary electrochemical enhancement area, and adjusting current density and electrifying time in the operation process to improve methanogen activity; the generated oxygen is dissolved in the water, and the water enters a second microorganism treatment area after being discharged.

S40, the bottom of the second microorganism processing area is an anoxic area, total nitrogen is continuously removed through denitrifying bacteria, and organic matters are removed through the action of methanogens in the upper area. Biogas generated by anaerobic treatment in the second microbial treatment area enters a third gas-liquid separator independent at the top through a second three-phase separator, gas such as methane enters a biogas treatment system, and the rest sludge in the sewage is separated and enters the bottom of the second microbial treatment area; the upper part of the second-stage three-phase separator is provided with a first circulation inlet, the upper part of the second-stage electrochemical enhancement area is provided with a first circulation outlet, and the integral ascending flow rate of the second microorganism treatment area is controlled through the flow of an external pump.

And S50, the effluent treated in the second microorganism treatment area enters a sludge precipitation area, and the effluent after sludge precipitation is discharged through an overflow weir.

According to the sewage denitrification and decarbonization treatment process, the culture of dominant floras at different heights is realized through the independent multi-stage internal circulation design, and the removal efficiency is higher. The conventional reactor is only provided with one internal circulation downcomer, and the downcomer is used for distributing sewage and sludge to a bottom water distribution system, so that the existence of various dominant strains with different heights cannot be realized.

In addition, in the treatment process of the invention, the electrochemical gas production internal circulation and the multistage external circulation system are arranged in the reactor, except for the internal circulation pipeline of the sewage driven by the methane. The first-stage electrochemical enhancement area generates hydrogen and oxygen, wherein the oxygen is dissolved in water, the residual hydrogen and gas such as methane generated by methanogens and nitrogen generated by denitrifying bacteria carry sewage and independently enter a first gas-liquid separator corresponding to the top of the first-stage electrochemical enhancement area for separation, and the sewage returns to the position of a water inlet distributor through a first descending pipe, so that heat exchange is realized, stirring is enhanced, and the mass transfer efficiency is improved.

The microbial treatment areas are respectively a first microbial treatment area and a second microbial treatment area from bottom to top, the first microbial treatment area and the second microbial treatment area are respectively matched with corresponding gas-liquid separators, mud and water separated by the gas-liquid separators enter the corresponding areas, and are matched with independent external forced circulation, the reflux ratio can be independently controlled according to the sludge specific gravity and control conditions of each area, and the sludge expansion heights of different reaction areas are realized. And a two-stage anoxic-anaerobic environment is established, so that the synchronous removal of total nitrogen and COD is realized.

Example 1

The reactor of the embodiment has a diameter of 10m and a height of 20m, and is internally provided with a primary electrochemical enhancement area, a first microbial treatment area, a secondary electrochemical enhancement area, a second microbial treatment area and a sludge settling area from bottom to top. The volume ratio between the primary electrochemical enhancement zone and the secondary electrochemical enhancement zone is 5: 4, the volume ratio between the first microbial treatment zone and the second microbial treatment zone is 1.3: 1.

the primary electrochemical enhancement zone is provided with 5 layers of polar plates, the polar plates are made of titanium plates, and the distance between the polar plate at the bottommost layer and the top of the water distributor is 300 mm; the secondary electrochemical enhancement zone is provided with 4 layers of polar plates, the polar plates are aluminum plates, and the distance between the polar plate at the bottommost layer and the top of the primary three-phase separator is 500 mm. The electrode plate length is 0.8m, and unilateral width is 0.3m, and thickness is 1mm, and the type of falling V contained angle is 50 degrees, and the circular port diameter that distributes on the polar plate is 2cm, and the interval between two holes is 8 cm.

The number of the gas collecting hood is 3, the length of a single gas collecting hood is 2m, the width of a single side is 30cm, the thickness is 3mm, the shape of the gas collecting hood is an inverted V shape, and the top of the V shape is a circular structure with the radius of 1/3 cm; the distance between the upper layer gas-collecting hood and the lower layer gas-collecting hood is 10cm, and the distance between the same layer gas-collecting hood is 10 cm.

The reactor is adopted to carry out the sewage denitrification and carbon removal treatment process, the reaction pH value in the primary electrochemical enhancement area is controlled to be 5.5, the dissolved oxygen is controlled to be 0.5mg/L, the sludge concentration is 5000mg/L, the reaction temperature is 28 ℃, and the current density range is 100mA/cm²(ii) a The sludge concentration MLSS of the first microorganism treatment area is 8000mg/L, the reaction temperature is 30 ℃, the pH value is 6.5, the rising flow rate is controlled to be 3m/h, and the reflux quantity Q₁Is 230m³H is used as the reference value. The dissolved oxygen of the secondary electrochemical enhancement region is 0.5mg/L, the reaction temperature is 30 ℃, and the current density range is 80mA/cm²(ii) a The sludge concentration of the second microorganism treatment area is 5000mg/L, the reaction temperature is 30 ℃, the pH value of inlet water is 6.5, the rising flow rate is 2m/h, and the reflux quantity is 150m³/h。

After the denitrification and decarbonization treatment is carried out on the sewage by the reactor of the embodiment, the COD of the sewage inlet water is 4500mg/L, the total nitrogen is 120mg/L, and the COD of the sewage inlet water is reduced to 540mg/L, and the total nitrogen is 45 mg/L.

Example 2

The basic contents of this embodiment are the same as embodiment 1, except that: the diameter of the reactor is 6m, the height is 16m, and the volume ratio of the primary electrochemical enhancement zone to the secondary electrochemical enhancement zone is 1: 1, the volume ratio between the first microbial treatment zone and the second microbial treatment zone is 1.5: 1. the primary electrochemical enhancement region is provided with 3 layers of polar plates, and the polar plates are made of titanium plates; the secondary electrochemical enhancement area is provided with 3 layers of polar plates, and the polar plates are made of titanium plates. The number of the gas collecting hoods is 4 layers.

The reactor is adopted to carry out the sewage denitrification and carbon removal treatment process, the reaction pH value in the primary electrochemical enhancement area is controlled to be 5.5, the dissolved oxygen is controlled to be 0.5mg/L, the sludge concentration is 6000mg/L, the reaction temperature is 25 ℃, and the current density range is 150mA/cm²(ii) a The sludge concentration MLSS of the first microorganism treatment area is 8000mg/L, the reaction temperature is 28 ℃, the pH value is 6.8, the rising flow rate is controlled to be 2.5m/h, and the reflux quantity Q₁Is 70m³H is used as the reference value. The dissolved oxygen of the secondary electrochemical enhancement region is 0.4mg/L, the reaction temperature is 28 ℃, and the current density range is 100mA/cm²(ii) a The sludge concentration of the second microorganism treatment zone is 5000mg/L, the reaction temperature is 28 ℃, the pH value of inlet water is 7.0, the rising flow rate is 2m/h, and the reflux amount is 55m³/h。

After the denitrification and decarbonization treatment is carried out on the sewage by the reactor of the embodiment, the COD of the sewage inlet water is 5500mg/L, the total nitrogen is 80mg/L, and the COD of the sewage outlet water is reduced to 780mg/L, and the total nitrogen is 25 mg/L.

Example 3

The basic contents of this embodiment are the same as embodiment 1, except that: the diameter of the reactor is 8m, the height is 18m, and the volume ratio between the primary electrochemical enhancement zone and the secondary electrochemical enhancement zone is 7: 5, the volume ratio between the first microbial treatment zone and the second microbial treatment zone is 1.5: 1. the primary electrochemical enhancement region is provided with 7 layers of polar plates, and the polar plates are made of graphite plates; the secondary electrochemical enhancement region is provided with 5 layers of polar plates, and the polar plates are made of iron plates. The number of the gas collecting hoods is 4 layers.

The reactor is adopted to carry out the sewage denitrification and carbon removal treatment process, the reaction pH value in the primary electrochemical enhancement area is controlled to be 5.5, the dissolved oxygen is controlled to be 0.3mg/L, the sludge concentration is 5500mg/L, the reaction temperature is 25 ℃, and the current density range is 200mA/cm²(ii) a The sludge concentration MLSS of the first microorganism treatment area is 9000mg/L, the reaction temperature is 28 ℃, the pH value is 7.0, the rising flow rate is controlled to be 4m/h, and the reflux quantity Q₁Is 200m³H is used as the reference value. The dissolved oxygen of the secondary electrochemical enhancement region is 0.3mg/L, the reaction temperature is 28 ℃, and the current density range is120mA/cm²(ii) a The sludge concentration of the second microorganism treatment zone is 5000mg/L, the reaction temperature is 28 ℃, the pH value of inlet water is 7.2, the rising flow rate is 2m/h, and the reflux quantity is 100m³/h。

After the sewage is subjected to denitrification and decarbonization treatment by the reactor of the embodiment, the COD of the inlet water of the sewage is 6300mg/L, the total nitrogen is 140mg/L, and the COD of the outlet water is reduced to 720mg/L, and the total nitrogen is 35 mg/L.

The present invention and its embodiments have been described above schematically, the description is not restrictive, the data used are only one of the embodiments of the present invention, and the actual data combination is not limited to this. Therefore, if the person skilled in the art receives the teaching, the embodiments and examples similar to the above technical solutions shall not be designed in an inventive manner without departing from the spirit of the present invention, and shall fall within the protection scope of the present invention.