CN111499120A

CN111499120A - Treatment system and method for denitration catalyst regeneration wastewater

Info

Publication number: CN111499120A
Application number: CN202010459674.3A
Authority: CN
Inventors: 郭文亮; 任启柏
Original assignee: Datang Nanjing Environmental Protection Technology Co Ltd
Current assignee: Datang Nanjing Environmental Protection Technology Co Ltd
Priority date: 2020-05-27
Filing date: 2020-05-27
Publication date: 2020-08-07

Abstract

The invention discloses a system and a method for treating denitration catalyst regeneration wastewater, wherein the wastewater passes through a regulating tank and then sequentially passes through a primary reaction tank, a primary sedimentation tank, a secondary reaction tank, a secondary sedimentation tank, a tertiary reaction tank and a tertiary sedimentation tank, and sludge in the primary sedimentation tank, the secondary sedimentation tank and the tertiary sedimentation tank enters a sludge tank; the wastewater treated by the third-stage reaction tank enters an intermediate water tank, then sequentially passes through a cooling tower, a hydrolysis acidification tank, an aerobic tank, an MBR membrane biological reaction tank and a discharge water tank, and is discharged after reaching the standard; an active carbon filter/physicochemical dosing device is arranged behind the discharge water tank, when raw water is abnormal or an accident occurs, the quality of effluent water can be ensured to be discharged up to the standard through the treatment of the active carbon filter/physicochemical dosing device, the treatment effect is good, the requirement of industrial wastewater discharge up to the standard can be fully met, and the treatment requirement of various denitration catalysts (including plate-type denitration catalysts and honeycomb denitration catalysts) on regenerated wastewater can be met.

Description

Treatment system and method for denitration catalyst regeneration wastewater

Technical Field

The invention relates to a system and a method for treating denitration catalyst regeneration wastewater, and belongs to the technical field of industrial wastewater treatment.

Background

The implementation of the emission Standard of atmospheric pollutants for thermal power plants (GB 13223-2011) puts higher requirements on the emission concentration of nitrogen oxides in coal-fired power plants, and the coal-fired power plants are generally additionally provided with selective catalytic reduction (S) to realize the emission reaching the standardCR) flue gas denitration device, SCR technique account for more than 95% of coal fired power plant flue gas denitration project. As the core of SCR technology, the catalyst is mainly V₂O₅-TiO₂System (addition of WO)₃Or MoO₃As an auxiliary) with a life cycle of about 3 years. When the denitration catalyst is used in a coal-fired power plant, a large amount of heavy metals such as chromium, beryllium, arsenic and mercury in flue gas can cause secondary pollution to the catalyst, so that the catalyst becomes dangerous waste rich in various heavy metal components. The SCR denitration catalyst regeneration technology can prolong the service life of the catalyst, reduce the operation cost of a power plant, reduce the treatment and disposal cost of the waste catalyst and bring the environmental pollution, so that the denitration catalyst regeneration is an inevitable requirement for the current industry development.

The denitration catalyst regeneration process unit mainly comprises the steps of initial evaluation, pretreatment, physical cleaning, chemical cleaning, active component implantation, drying, calcination and the like, and a water process is involved, so that a large amount of industrial wastewater is generated. The main pollutant generated in the physical cleaning process is cleaning wastewater containing high-concentration suspended matters, and the chemical cleaning process mainly generates wastewater containing heavy metals such as vanadium, lead, mercury, arsenic, cadmium, chromium, copper, iron, hexavalent chromium and the like and organic matters.

The key point of the wastewater treatment generated in the regeneration production process of the SCR flue gas denitration catalyst is cleaning or activating wastewater generated in the physical and chemical cleaning and active implantation processes, the cleaning or activating wastewater is collected and treated in a centralized way according to the characteristic classification of the wastewater, and heavy metal ions, ammonia nitrogen, organic matters and the like in the wastewater are treated preferentially. The method for precipitating by adding a precipitator and a flocculating agent can effectively remove heavy metal ions in the wastewater, the method for treating ammonia nitrogen in the wastewater mainly comprises a breakpoint chlorination method, an adsorption method and a biological method, and the biological method is still the most stable and effective method for treating organic matters in the wastewater at present.

The existing SCR flue gas denitration catalyst regeneration wastewater treatment process mainly faces the following problems: 1) the regeneration project period of each batch of old catalysts is short (different from days to tens of days), the projects are frequently replaced, the substances causing the poisoning of the old catalysts in different batches are greatly different, and factors such as alkali metal poisoning, arsenic poisoning, pore channel blockage caused by fly ash, ammonium sulfate salt deposition and the like exist, for example, the arsenic poisoning degree of the SCR flue gas denitration catalyst is serious, and the arsenic content of the treated wastewater can hardly meet the requirements of the emission standard of vanadium industrial pollutants by only depending on a single advanced oxidation process. 2) On the other hand, due to different poisoning degrees of different batches of old catalysts, the adding amount of chemical agents in the subsequent wastewater pretreatment process is very different, so that the wastewater which enters a biochemical system after pretreatment has high salinity (mainly containing sodium sulfate) and large fluctuation, and troubles are brought to the stable operation of the biochemical system.

Because the requirement of the microbial flora of the biochemical system on the living environment is harsh, external conditions such as relatively constant temperature, pH value, salinity (measured by electric conductivity) and the like are required, and the adaptation of the microorganisms of the biochemical system to the new environment requires a relatively long period. If the fluctuation range of water quality is too large (for example, the ammonia nitrogen content of wastewater generated in the regeneration process of a catalyst is too high due to excessive ammonia spraying), the nitrification and denitrification flora needs a long-term adaptation process for the suddenly rising ammonia nitrogen, and the biochemical system can reach the designed ammonia nitrogen removal efficiency and cause certain pressure for the continuous drainage of the ammonia nitrogen which reaches the standard and is discharged.

Disclosure of Invention

The invention aims to provide a system and a method for treating denitration catalyst regeneration wastewater, which have good treatment effect, can fully meet the requirement of standard emission of industrial wastewater, and can meet the treatment requirement of regeneration wastewater of various denitration catalysts (including plate-type denitration catalysts and honeycomb denitration catalysts).

A denitration catalyst regeneration wastewater treatment system comprises an adjusting tank, a primary reaction tank, a primary sedimentation tank, a secondary reaction tank, a secondary sedimentation tank, a tertiary reaction tank, a tertiary sedimentation tank, an intermediate water tank, a cooling tower, a hydrolysis acidification tank, an aerobic tank, an MBR membrane biological reaction tank, a discharge water tank, an activated carbon filter/physicochemical dosing device and a sludge tank; the primary reaction tank is divided into five unit reaction tanks, namely an iron-carbon micro-electrolysis reaction tank, a persulfate (or hydrogen peroxide) reaction tank, a ferrous sulfate reaction tank, a pH reaction tank and a PAM flocculation reaction tank;the secondary reaction tank comprises a pH reaction tank and FeSO₄A reaction tank and a PAM reaction tank; the three-stage reaction tank comprises a pH reaction tank, a heavy-duty agent reaction tank and FeSO₄A reaction tank and a PAM reaction tank; the wastewater passes through the regulating tank and then sequentially passes through the primary reaction tank, the primary sedimentation tank, the secondary reaction tank, the secondary sedimentation tank, the tertiary reaction tank and the tertiary sedimentation tank, and sludge in the primary sedimentation tank, the secondary sedimentation tank and the tertiary sedimentation tank enters the sludge tank; the wastewater treated by the third-stage reaction tank enters an intermediate water tank, then sequentially passes through a cooling tower, a hydrolysis acidification tank, an aerobic tank, an MBR membrane biological reaction tank and a discharge water tank, and is discharged after reaching the standard; an active carbon filter/physicochemical dosing device is arranged behind the discharge water tank, and when the raw water is abnormal or an accident occurs, the quality of the discharged water can be ensured to be discharged up to the standard through the treatment of the active carbon filter/physicochemical dosing device.

A denitration catalyst regeneration wastewater treatment method comprises the following steps:

pumping wastewater generated in the regeneration process of the denitration catalyst into a regulating tank by a regeneration workshop, paving a perforated aeration pipe at the bottom of the regulating tank, regulating the water quality and the water quantity by air stirring, and then lifting the wastewater by a lifting pump to enter a wastewater treatment system;

b, lifting the wastewater uniformly mixed by air stirring in the step a to a primary reaction tank, wherein the primary reaction tank is divided into 5 reaction units, and the first unit comprises a microelectrolysis filler phi 85 x 30 and a specific gravity: 1.1t/m³Specific surface area: 1.2m²(iv)/g, porosity: 68.5%, physical strength: not less than 1000kg/cm²The chemical composition is as follows: 75-85% of Fe and 10-20% of C. The method comprises the steps of firstly adding sulfuric acid into wastewater through a dosing pump to adjust the pH value, adding persulfate (or hydrogen peroxide) into a second unit, mixing through mechanical stirring, introducing air, stirring, adding ferrous sulfate into a third unit, ensuring that a medicament is fully mixed with the wastewater through mechanical stirring, oxidizing low-valence metal ions (As and Cr) in the wastewater, oxidizing a part of organic matters (vitamin C), improving the biodegradability of the wastewater and reducing the COD value in the wastewater. After the oxidation reaction is finished, liquid caustic soda is added into the fourth unit to adjust the pH value back, and finally, negative Polyacrylamide (PAM) is added into the fifth unit for flocculation, so that the precipitation is facilitatedAnd (4) separating by precipitation.

c, enabling the wastewater after the reaction in the step b to enter a primary sedimentation tank for primary sedimentation, adopting a high-efficiency inclined plate sedimentation tank to perform mud-water separation on the mixed liquid after the reaction, and discharging the sludge after sedimentation into a sludge tank;

d, introducing the wastewater subjected to precipitation treatment in the step c into a secondary reaction tank, adjusting the pH value to an alkaline state, adding ferrous sulfate and PAM for coagulation;

e, enabling the wastewater after the reaction in the step d to enter a secondary sedimentation tank for secondary sedimentation, adopting a high-efficiency inclined plate sedimentation tank to perform mud-water separation on the mixed liquid after the reaction, and discharging the sludge after sedimentation into a sludge tank;

and f, introducing the wastewater subjected to precipitation treatment in the step e into a three-stage reaction tank, firstly adjusting the pH value, then adding a heavy metal capture agent for reaction, enlarging alum flocs under the action of PAM after the precipitation is formed, and accelerating the precipitation, wherein the heavy metal possibly remained in the reaction in the stage is mainly removed.

g, feeding the wastewater after the reaction in the step f into a third-stage sedimentation tank for third-stage sedimentation, adopting a high-efficiency inclined plate sedimentation tank to separate the sludge and the water of the mixed liquid after the reaction, and discharging the sludge after the sedimentation into sludge;

and h, automatically flowing the wastewater to an intermediate water tank after the pretreatment reaction is finished, and lifting the wastewater by a lifting pump to pass through a cooling tower to ensure that the water temperature is below 40 ℃.

i, introducing the wastewater cooled by the cooling tower in the step h into a hydrolysis acidification tank, and hydrolyzing refractory substances to improve the biodegradability of the wastewater;

j, introducing the hydrolyzed wastewater in the step i into an aerobic tank, and removing organic pollutants through microbial degradation;

k, lifting the wastewater treated in the step j to a membrane bioreactor through a lifting pump, completing mud-water separation through the filtering action of a membrane, reducing pollution factors such as COD (chemical oxygen demand), SS (suspended substances) and the like, and ensuring that the water quality reaches the standard and is discharged;

l: introducing the wastewater treated in the step k into a discharge water tank;

m: the activated carbon filter/physicochemical dosing device is taken as an emergency measure, and can ensure that the effluent quality reaches the standard and is discharged when the raw water is abnormal or an accident occurs.

n: sludge generated by the whole wastewater treatment system enters a sludge tank, and is dehydrated after being subjected to filter pressing by a plate frame.

Preferably, in the step b, sulfuric acid is added into the first unit to adjust the pH value to 3.0-5.0, persulfate is added into the second unit to control the concentration of persulfate in the wastewater to be 200-1500 mg/L), or hydrogen peroxide is added to control the concentration of hydrogen peroxide in the wastewater to be 200-1500 mg/L, ferrous sulfate is added into the third unit to control the concentration of ferrous sulfate in the wastewater to be 1000-3000 mg/L, after the oxidation reaction is completed, liquid alkali is added into the fourth unit to adjust the pH value to be about 7.0, and finally, anionic Polyacrylamide (PAM) is added into the fifth unit for flocculation to control the concentration of PAM in the wastewater to be 5-10 mg/L.

Preferably, in step d, the pH is adjusted to 9.5-10.5, then ferrous sulfate and PAM are added for coagulation, the concentration of ferrous sulfate in the wastewater is controlled at 3000 mg/L, and the concentration of PAM in the wastewater is controlled at 5-10 mg/L.

Preferably, in the step f, the pH value is adjusted to 10.0-11.0, a heavy metal catching agent is added, the concentration of the heavy metal in the wastewater is controlled to be 60-300 mg/L adding amount, and the concentration of PAM in the wastewater is controlled to be 5-10 mg/L.

The invention particularly provides a novel treatment system and a novel treatment method for denitration catalyst regeneration wastewater, which mainly solve the following problems that 1) aiming at serious arsenic poisoning degree, only a single advanced oxidation process is relied on, the arsenic content of the treated wastewater can not meet the requirements of vanadium industrial pollutant emission standard, an iron-carbon micro-electrolysis combined advanced oxidation technology is used as a first-stage reaction, meanwhile, a heavy metal catching agent is added into a third-stage reaction tank of a step e for reaction, heavy metals possibly remaining after treatment of the steps b and d are mainly removed, and an activated carbon filter is added behind an MBR membrane tank as an emergency measure, so that the heavy metals in water quality can reach the standard. 2) Aiming at the problem that the ammonia nitrogen content of the wastewater generated in the catalyst regeneration process is too high due to excessive ammonia spraying, a biochemical system nitrification and denitrification flora needs a long-term adaptation process to the suddenly rising ammonia nitrogen to achieve the designed ammonia nitrogen removal efficiency, an activated carbon filter/physicochemical dosing device (a folding point chlorination device) is additionally arranged behind an MBR membrane pool as an emergency measure, and when the ammonia nitrogen content of the wastewater is too high or raw water is abnormal, the effluent quality can be guaranteed to reach the standard and be discharged. 3) And d, adding ferrous sulfate and PAM to further pretreat the wastewater treated in the step c by adjusting the pH to an alkaline state, so as to prevent the occurrence of the condition of muddy water separation caused by the abnormality of the raw wastewater in the step a or the poor flocculation effect in the step c.

Compared with the prior art, the invention has the following advantages:

in the step b, aiming at the serious arsenic poisoning degree, only depending on a single advanced oxidation process, the arsenic content of the treated wastewater can not be ensured to meet the requirements of the emission standard of pollutants in vanadium industry, the iron-carbon micro-electrolysis combined advanced oxidation technology is used as a first-stage reaction, and the iron-carbon micro-electrolysis combined persulfate technology is used for pretreatment of the regenerated wastewater of the denitration catalyst.

In the step m, aiming at the condition that the ammonia nitrogen content of the wastewater generated in the catalyst regeneration process is too high due to excessive ammonia spraying, a biochemical system nitrification and denitrification flora needs a long-term adaptation process to the suddenly rising ammonia nitrogen to achieve the designed ammonia nitrogen removal efficiency, an activated carbon filter/physicochemical medicine adding device (a break point chlorine adding device) is additionally arranged behind an MBR membrane pool as an emergency measure, when the ammonia nitrogen content of the wastewater is too high or the raw water is abnormal, the effluent quality can be ensured to reach the standard and be discharged, and the finally treated water quality is up to the standard as shown in Table 2.

And c, e and g, adopting a high-efficiency inclined plate sedimentation tank, and being more beneficial to carrying out mud-water separation on the mixed liquid after reaction.

And d, adjusting the pH value to be in an alkaline state, adding ferrous sulfate and PAM to further pretreat the wastewater treated in the step c, and preventing the muddy water from being not separated due to the abnormality of the original wastewater in the step a or the poor flocculation effect in the step c.

And e, adding a heavy metal catching agent for reaction, mainly removing heavy metals possibly remaining after treatment in the steps b and d, and ensuring that heavy metal pollutants in the water reach the standard.

And (e) returning part of the residual sludge generated by the membrane bioreactor in the step k to the hydrolysis acidification tank in the step i, and removing part of ammonia nitrogen through nitrification and denitrification.

Has the advantages that:

the invention takes the iron-carbon micro-electrolysis combined with the advanced oxidation technology as a primary main reaction, the iron-carbon micro-electrolysis combined with the persulfate technology is firstly used for the pretreatment of the denitration catalyst regeneration wastewater, and the treated wastewater reaches the discharge standard of vanadium industrial pollutants (GB 26452-2011).

Drawings

The invention is described in further detail below with reference to the figures and the detailed description.

FIG. 1 is a block diagram of the process of the present invention;

FIG. 2 is a schematic view of a first-stage reaction tank;

FIG. 3 is a schematic view of a two-stage reaction tank;

FIG. 4 is a schematic structural diagram of a three-stage reaction tank.

Detailed Description

Specific examples of the present invention are given below, which are intended to further illustrate the present invention and do not limit the scope of the claims of the present invention.

Heavy metal ions in cleaning or activating wastewater generated in the processes of physical and chemical cleaning and active implantation in the regeneration process of the denitration catalyst can be treated in a centralized way, and the main treatment way is to take lime, ferric salt, sodium sulfide and a flocculating agent as raw materials to precipitate and polymerize heavy metal pollutants such as arsenic, vanadium and the like in the wastewater, so that a stable polymer is formed and exists in sludge to achieve the aim of removing the heavy metal pollutants; for organic matters, chemical oxidation method can be adopted to decompose the organic matters, or biological method (such as aerobic/anaerobic reaction and MBR membrane biological reaction) is adopted to remove the organic matters; the ammonia nitrogen pollution can be treated by a breakpoint chlorination method, an activated carbon adsorption method or a biological method.

Example 1

A denitration catalyst regeneration wastewater treatment system comprises an adjusting tank, a first-stage reaction tank (iron-carbon micro-electrolysis combined advanced oxidation technology), a first-stage sedimentation tank, a second-stage reaction tank, a second-stage sedimentation tank, a third-stage reaction tank, a third-stage sedimentation tank, an intermediate water tank, a hydrolysis acidification tank, an aerobic tank, a Membrane Bioreactor (MBR), a discharge water tank, an active carbon filter/physicochemical dosing device and a sludge tank. The reaction tanks are connected in sequence. The dimensional and material properties of each part are shown in Table 1. The primary reaction tank is divided into five unit reaction tanks which are respectively a micro-electrolysis filler unit, a persulfate oxidation unit, a ferrous sulfate oxidation unit, a pH regulation unit and a PAM flocculation unit; the secondary reaction tank comprises a pH reaction tank and FeSO₄A reaction tank and a PAM reaction tank; the three-stage reaction tank comprises a pH reaction tank, a heavy-duty agent reaction tank and FeSO₄A reaction tank and a PAM reaction tank; the wastewater passes through the regulating tank and then sequentially passes through the primary reaction tank, the primary sedimentation tank, the secondary reaction tank, the secondary sedimentation tank, the tertiary reaction tank and the tertiary sedimentation tank, and sludge in the primary sedimentation tank, the secondary sedimentation tank and the tertiary sedimentation tank enters the sludge tank; the wastewater treated by the third-stage reaction tank enters an intermediate water tank, then sequentially passes through a cooling tower, a hydrolysis acidification tank, an aerobic tank, an MBR membrane biological reaction tank and a discharge water tank, and is discharged after reaching the standard; an active carbon filter/physicochemical dosing device is arranged behind the discharge water tank, and when the raw water is abnormal or an accident occurs, the quality of the discharged water can be ensured to be discharged up to the standard through the treatment of the active carbon filter/physicochemical dosing device. The carbon source adding device is connected with the aerobic tank.

Table 1:

example 2

Waste water generated in the regeneration process of the denitration catalyst enters an adjusting tank to be adjusted in water quality and water quantity and then is lifted by a lifting pump to enter a waste water treatment system.

The method comprises the steps of lifting wastewater into a first-stage reaction tank, wherein the first-stage reaction tank is divided into 5 reaction units, firstly sulfuric acid is added into a first-unit iron-carbon micro-electrolysis reaction tank to adjust the pH value to 3.0, the reaction time is 30min, hydrogen peroxide (adding amount: the concentration of hydrogen peroxide in wastewater is controlled to be 500 mg/L) is added into a second unit, ferrous sulfate (adding amount: the concentration of ferrous sulfate in wastewater is controlled to be 1500 mg/L) is added into a third unit, the chemical agent is fully mixed with the wastewater through mechanical stirring, low-valence metal ions (As) in the wastewater are oxidized, a part of organic matters (vitamin C) are oxidized at the same time, the biodegradability of the wastewater is improved, the COD value in the wastewater is reduced, after the oxidation reaction is completed, the pH value is adjusted to be about 7.0 by adding liquid alkali into a fourth unit, and finally, anionic Polyacrylamide (PAM) is added into a fifth unit for flocculation (adding amount: the concentration of PAM in the wastewater is controlled to be 5-.

And after the reaction, the mixed liquor enters a primary sedimentation tank for sedimentation, the mixed liquor after the reaction is subjected to mud-water separation by adopting a high-efficiency inclined plate sedimentation tank, and the sludge after sedimentation is discharged into a sludge tank.

The effluent of the primary sedimentation tank enters a secondary reaction tank, the pH value is adjusted to 9.5-10.5, then ferrous sulfate (the adding amount: the concentration of the ferrous sulfate in the wastewater is controlled at 1000 mg/L) and PAM (the adding amount: the concentration of the PAM in the wastewater is controlled at 5 mg/L) are added in sequence for coagulation sedimentation,

the effluent of the secondary reaction tank enters a secondary sedimentation tank, a high-efficiency inclined plate sedimentation tank is adopted to separate the sludge and water of the mixed liquid after reaction, and the sludge after sedimentation is discharged into a sludge tank;

and (3) enabling the effluent of the secondary sedimentation tank to enter a tertiary reaction tank, firstly adjusting the pH value to 10.0-11.0, then adding a heavy metal capture agent (the adding amount: the concentration of the heavy metal in the wastewater is controlled at 100 mg/L) for reaction, then adding ferrous sulfate (the adding amount: the concentration of the ferrous sulfate in the wastewater is controlled at 500 mg/L), and PAM (the adding amount: the concentration of the PAM in the wastewater is controlled at 5-10 mg/L) for coagulation sedimentation, wherein the potential residual heavy metal pollutants are mainly removed in the primary reaction.

And the effluent of the third-stage reaction tank enters a third-stage sedimentation tank, a high-efficiency inclined plate sedimentation tank is adopted to separate the sludge and water of the mixed liquid after reaction, and the sludge after sedimentation is discharged into a sludge tank.

After the pretreatment is finished, the pH value of the wastewater is controlled to be 6-9, the wastewater automatically flows to an intermediate water tank, and is lifted by a lifting pump to pass through a cooling tower, so that the water temperature is ensured to be below 40 ℃.

And the cooled wastewater enters a hydrolysis acidification tank to hydrolyze the refractory substances, so that the biodegradability of the wastewater is improved.

The hydrolyzed waste water enters an aerobic tank, and organic pollutants are removed through the degradation of microorganisms.

The effluent of the aerobic tank is lifted to a membrane bioreactor through a lift pump, sludge-water separation is completed through the filtering action of the membrane, pollution factors such as COD (chemical oxygen demand), SS (suspended substance) and the like are reduced, and the treated wastewater reaches the discharge standard of pollutants for vanadium industry (GB 26452-2011) shown in Table 2.

Table 2:

the activated carbon filter/physicochemical dosing device is taken as an emergency measure, and can ensure that the effluent quality reaches the standard and is discharged when the raw water is abnormal or an accident occurs.

Sludge generated by the whole wastewater treatment system enters a sludge tank, and is dehydrated after being subjected to filter pressing by a plate frame.

Example 3

The method comprises the steps of lifting wastewater into a first-stage reaction tank, wherein the first-stage reaction tank is divided into 5 reaction units, firstly, sulfuric acid is added into a first-unit iron-carbon micro-electrolysis reaction tank to adjust the pH value to 5.0, the reaction time is 60min, persulfate is added into a second unit (the adding amount: the concentration of the persulfate in the wastewater is controlled to be 1500 mg/L)), ferrous sulfate is added into a third unit (the adding amount: the concentration of the ferrous sulfate in the wastewater is controlled to be 2500 mg/L), the chemical is fully mixed with the wastewater through mechanical stirring, low-valence metal ions (As) in the wastewater are oxidized, a part of organic matters (vitamin C) are oxidized at the same time, the biodegradability of the wastewater is improved, the COD value in the wastewater is reduced, after the oxidation reaction is completed, liquid alkali is added into a fourth unit to adjust the pH value to be about 7.0, and finally, anionic Polyacrylamide (PAM) is added into a fifth unit to flocculate (the adding amount: the concentration of the PAM in the.

The effluent of the primary sedimentation tank enters a secondary reaction tank, the pH is adjusted to 9.5-10.5, and then ferrous sulfate (the adding amount is that the concentration of the ferrous sulfate in the wastewater is controlled at 2500 mg/L) and PAM (the adding amount is that the concentration of the PAM in the wastewater is controlled at 10 mg/L) are sequentially added for coagulating sedimentation;

and (3) enabling the effluent of the secondary sedimentation tank to enter a tertiary reaction tank, firstly adjusting the pH value to 10.0-11.0, then adding a heavy metal capture agent (the adding amount: the concentration of the heavy metal in the wastewater is controlled at 300 mg/L) for reaction, then adding ferrous sulfate (the adding amount: the concentration of the ferrous sulfate in the wastewater is controlled at 800 mg/L), and PAM (the adding amount: the concentration of the PAM in the wastewater is controlled at 5-10 mg/L) for coagulation sedimentation, wherein the potential residual heavy metal pollutants are mainly removed in the primary reaction.

The effluent of the aerobic tank is lifted to a membrane bioreactor through a lifting pump, and the sludge-water separation is completed through the filtering action of the membrane, so that pollution factors such as COD (chemical oxygen demand), SS (suspended solid) and the like are reduced. The treated wastewater reaches the discharge standard of vanadium industrial pollutants (GB 26452-2011).

The above description is only exemplary of the present invention and should not be taken as limiting the invention, and any modifications, equivalents, improvements, etc. that are made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A denitration catalyst regeneration wastewater treatment method is characterized by comprising the following steps:

pumping waste water generated in the regeneration process of a denitration catalyst into an adjusting tank from a regeneration workshop, paving a perforated aeration pipe at the bottom of the adjusting tank, adjusting the water quality and the water quantity by air stirring, and then lifting the waste water by a lifting pump to enter a waste water treatment system;

b, lifting the wastewater uniformly mixed by air stirring in the step a to a primary reaction tank, wherein the primary reaction tank is divided into 5 reaction units, the first unit is used for carrying out iron-carbon micro-electrolysis, the wastewater is firstly added with sulfuric acid through a dosing pump to adjust the pH value, persulfate or hydrogen peroxide is added into the second unit to be mechanically stirred and mixed and is introduced with air to be stirred, ferrous sulfate is added into the third unit to be mechanically stirred to ensure that the medicament is fully mixed with the wastewater, metal ions in low valence state in the wastewater are oxidized, and a part of organic matters are oxidized at the same time, so that the biodegradability of the wastewater is improved and the COD value in the wastewater is reduced; after the oxidation reaction is finished, adding liquid caustic soda into the fourth unit to adjust the pH value back, and finally adding anionic polyacrylamide into the fifth unit for flocculation to generate alum floc which is convenient for precipitation and separation;

c, enabling the wastewater after the reaction in the step b to enter a primary sedimentation tank for primary sedimentation, carrying out mud-water separation on the mixed liquor after the reaction, and discharging the sludge after sedimentation into a sludge tank;

e, enabling the wastewater after the reaction in the step d to enter a secondary sedimentation tank for secondary sedimentation, carrying out mud-water separation on the mixed liquor after the reaction, and discharging the sludge after sedimentation into a sludge tank;

introducing the wastewater subjected to precipitation treatment in the step e into a three-stage reaction tank, firstly adjusting the pH value, then adding a heavy metal capture agent for reaction, accelerating precipitation under the action of PAM after the precipitation is formed, and mainly removing the heavy metal possibly remained in the reaction of the stage;

g, feeding the wastewater after the reaction in the step f into a third-stage sedimentation tank for third-stage sedimentation, carrying out sludge-water separation on the mixed liquor after the reaction, and discharging the sludge after sedimentation into a sludge tank;

h, automatically flowing the wastewater to an intermediate water tank after the pretreatment reaction is finished, and lifting the wastewater by a lifting pump to pass through a cooling tower to ensure that the water temperature is below 40 ℃;

j, the wastewater hydrolyzed in the step i enters an aerobic tank, and organic pollutants are removed through the degradation of microorganisms;

m: the activated carbon filter/physicochemical dosing device is taken as an emergency measure, and can ensure that the effluent quality reaches the standard and is discharged when the raw water is abnormal or an accident occurs;

2. The denitration catalyst of claim 1The regeneration wastewater treatment method is characterized in that in the step b, in the first unit iron-carbon micro-electrolysis, the filler phi 85 is 30, and the specific gravity is as follows: 1.1t/m³Specific surface area: 1.2m²(iv)/g, porosity: 68.5%, physical strength: not less than 1000kg/cm²The chemical composition is as follows: 75-85% of Fe and 10-20% of C.

3. The method for treating denitration catalyst regeneration wastewater as claimed in claim 1, wherein in step m, the physicochemical chemical-adding device is a break point chlorination device.

4. The system and the method for treating denitration catalyst regeneration wastewater as claimed in claim 1, wherein in the steps c, e and g, a high-efficiency inclined plate sedimentation tank is adopted for sedimentation, which is beneficial to sludge-water separation of the reacted mixed solution.

5. The system and method for treating denitration catalyst regeneration wastewater as claimed in claim 1, wherein the pH value in step d is adjusted to 9.5-10.5, ferrous sulfate and PAM are added for coagulation, the concentration of ferrous sulfate in wastewater is controlled to be 3000 mg/L, and the concentration of PAM in wastewater is controlled to be 5-10 mg/L.

6. The system and the method for treating denitration catalyst regeneration wastewater as claimed in claim 1, wherein in step f, the heavy metal capture agent is added, and the concentration of heavy metal in wastewater is controlled at 60-300 mg/L.

7. The system and the method for treating denitration catalyst regeneration wastewater as claimed in claim 1, wherein a part of residual sludge generated by the membrane bioreactor in step k can flow back to the hydrolysis acidification tank in step i, and part of ammonia nitrogen is removed by nitrification and denitrification.

8. A treatment system for denitration catalyst regeneration wastewater is characterized by comprising an adjusting tank, a first-stage reaction tank, a first-stage sedimentation tank, a second-stage reaction tank, a second-stage sedimentation tank and a third-stage reactionA pool, a third-stage sedimentation tank, an intermediate water pool, a cooling tower, a hydrolysis acidification tank, an aerobic tank, an MBR membrane biological reaction tank, a discharge water pool, an activated carbon filter/physicochemical dosing device and a sludge pool; the primary reaction tank is divided into five unit reaction tanks, namely an iron-carbon micro-electrolysis reaction tank, a persulfate (or hydrogen peroxide) reaction tank, a ferrous sulfate reaction tank, a pH reaction tank and a PAM flocculation reaction tank; the secondary reaction tank comprises a pH reaction tank and FeSO₄A reaction tank and a PAM reaction tank; the three-stage reaction tank comprises a pH reaction tank, a heavy-duty agent reaction tank and FeSO₄A reaction tank and a PAM reaction tank; the wastewater passes through the regulating tank and then sequentially passes through the primary reaction tank, the primary sedimentation tank, the secondary reaction tank, the secondary sedimentation tank, the tertiary reaction tank and the tertiary sedimentation tank, and sludge in the primary sedimentation tank, the secondary sedimentation tank and the tertiary sedimentation tank enters the sludge tank; the wastewater treated by the third-stage reaction tank enters an intermediate water tank, then sequentially passes through a cooling tower, a hydrolysis acidification tank, an aerobic tank, an MBR membrane biological reaction tank and a discharge water tank, and is discharged after reaching the standard; an active carbon filter/physicochemical dosing device is arranged behind the discharge water tank, and when the raw water is abnormal or an accident occurs, the quality of the discharged water can be ensured to be discharged up to the standard through the treatment of the active carbon filter/physicochemical dosing device.

9. The denitration catalyst regeneration wastewater treatment system of claim 8, further comprising a carbon source adding device, wherein the carbon source adding device is connected with the aerobic tank.