A method and device for treating nitramine explosive wastewater

Abstract

The invention discloses a nitramine explosive wastewater treatment method and a treatment device, comprising a regulating tank, a pre-oxidation tank, an electrolytic cell, a plug-flow internal circulation anaerobic reaction device, an aerobic treatment unit and an ozone deep oxidation denitrification unit which are connected in sequence; the plug-flow internal circulation anaerobic reaction device comprises an anaerobic sludge reaction zone and an anaerobic filler reaction zone which are connected in sequence; the combined technology of the pre-electrochemical coupling pretreatment technology, the plug-flow internal circulation anaerobic reaction device, the activated sludge strengthening process and the ozone deep oxidation post-treatment technology is integrated, the sludge expansion culture adaptability culture time is short and the cost is low.

Description

Technical Field

[0001] The invention relates to the field of industrial wastewater treatment, and in particular to a method and a device for treating nitramine explosive wastewater. Background Art

[0002] The explosives industry will generate a large amount of production wastewater containing nitramines, dinitrotoluene (DNT) and toluenediamine (TDA) during production. The composition of the wastewater is relatively complex, and the nitramines, nitrobenzene, aniline pollutants, COD, color, pH value (acidity) and other indicators in the wastewater are relatively high.

[0003] With the continuous development of wastewater treatment technology, explosive wastewater treatment technology has also been continuously improved. The main technologies currently used are physical and chemical methods, chemical technology, biological treatment technology and comprehensive application of various advanced technologies. Chinese patent CN100390081C discloses a method for treating wastewater containing nitrobenzene and aniline pollutants. The patent uses iron-carbon micro-electrolysis to treat wastewater containing nitrobenzene and aniline pollutants. This method mainly converts nitrobenzene into aniline, and then removes it by adsorption of iron hydroxide. The remaining nitrobenzene and aniline are mainly oxidized by Fenton's reagent. In addition to the complex operation and high cost, the large amount of sludge generated by internal electrolysis cannot be removed, which eventually leads to system compaction.

[0004] Chinese patent CN100417604C adopts a full biochemical treatment method for nitrobenzene and aniline wastewater, and the selected bacteria are HSB high-decomposition bacteria from Taiwan, China, which is not suitable for treating high-concentration wastewater, and the microorganisms need to be added every day, which has a high treatment cost.

[0005] Physical and chemical methods can only reduce one or several characteristic pollutants to a limited extent, and the secondary pollutants they cause are more difficult to treat; biological treatment technology is less difficult to implement in engineering, has safe process operations, low operating costs, and high pollutant removal rates, but there are also problems such as low microbial tolerance to pollution concentrations, slow degradation rates, and slow adaptation to bacterial strain cultivation; therefore, it has become an industry consensus that it is difficult for any single technology to achieve the goal of achieving standard discharge of explosives wastewater. Summary of the invention

[0006] The purpose of the present invention is to achieve stable and standard discharge of nitramine explosive wastewater, and to provide a combined technology that combines a front electrochemical coupling pretreatment technology with a plug-flow internal circulation anaerobic reaction device, an activated sludge enhancement process and an ozone deep oxidation post-treatment technology. The method and device for treating nitramine explosive wastewater have good sludge expansion adaptability, short cultivation time and low cost.

[0007] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is:

[0008] A nitramine explosive wastewater treatment device comprises a regulating tank, a pre-oxidation tank, an electrolytic cell, a plug-flow internal circulation anaerobic reaction device, an aerobic treatment unit and an ozone deep oxidation denitrification unit which are connected in sequence; the plug-flow internal circulation anaerobic reaction device comprises an anaerobic sludge reaction zone and an anaerobic filler reaction zone which are connected in sequence.

[0009] Preferably, the anaerobic sludge reaction zone comprises a sludge layer, a static separation layer, an inclined tube separation layer and a first water collecting tank from bottom to top; a first water distribution branch pipe is arranged at the bottom of the sludge layer, and a first sludge discharge branch pipe is arranged above the first water distribution branch pipe; a first nitrification liquid circulation branch pipe is arranged at the top of the sludge layer; one end of the first water distribution branch pipe is connected to the first water inlet pipe, and the other end is connected to the first circulation main pipe; a first water inlet valve is arranged on the side of the first water distribution branch pipe close to the first water inlet pipe, and a second water inlet valve is arranged on the side close to the first circulation main pipe; the first sludge discharge branch pipe, the first nitrification liquid circulation branch pipe and the first circulation main pipe are all connected to the first water inlet pipe. The circulation unit is connected, a remote liquid level gauge is arranged in the first water collecting tank, and an interlock is formed between the first water inlet valve and the second water inlet valve. The interlock principle is: when the first water inlet valve on a first water distribution branch pipe is closed, the corresponding second water inlet valve is opened, and the 10 branches are operated in sequence, that is to say, 5 branches are in operation for water inlet and 5 branches are in operation for circulating water distribution. The alternating operation realizes the position change of water inlet distribution and circulating water distribution. The changing multi-point water inlet ensures the homogeneous environment in the reactor, which is suitable for domesticating and cultivating adapted microbial communities, can give full play to the functions of each reaction system, and avoids the single function of the reaction system.

[0010] Preferably, a packing layer is arranged in the anaerobic packing reaction zone, and a second water collecting tank is arranged above the packing layer; a second water distribution branch pipe is arranged below the packing layer, and a second mud discharge branch pipe is arranged above the second water distribution branch pipe; a second nitrification liquid circulation branch pipe is arranged above the packing layer; one end of the second water distribution branch pipe is connected to the second water inlet pipe, and the other end is connected to the second circulation main pipe; a third water inlet valve is arranged on the side of the second water distribution branch pipe close to the second water inlet pipe, and a fourth water inlet valve is arranged on the side close to the second circulation main pipe; the second mud discharge branch pipe, the second nitrification liquid circulation branch pipe and the second circulation main pipe are all connected to the circulation unit; an interlock is formed between the third water inlet valve and the fourth water inlet valve, and the interlocking principle is similar to that of the first water inlet valve and the second water inlet valve.

[0011] Preferably, a boosting unit is further arranged between the anaerobic sludge reaction zone and the anaerobic filler reaction zone; the boosting unit comprises a first connecting pipe and a second connecting pipe, both of which are connected to a first water collecting tank and a second water inlet pipe; a parallel valve is arranged on the first connecting pipe, a first boosting pump is arranged on the second connecting pipe, an inlet valve is arranged on the side of the second water inlet pipe close to the first water collecting tank, and an outlet valve is arranged on the side close to the second water inlet pipe; an interlock is formed between the parallel valve, the first boosting pump, the inlet valve, the outlet valve and the remote level gauge; the specific interlocking relationship is: when the liquid level in the anaerobic sludge reaction zone is high, the parallel valve is closed, the inlet valve is opened, the first boosting pump is opened, and the outlet valve is opened to complete drainage; when the liquid level is low, the outlet valve is closed, the first boosting pump is stopped, the inlet valve is closed, the parallel valve is opened, and the liquid flows into the second water inlet pipe.

[0012] Preferably, the circulation unit includes a second booster pump and a mud discharge main pipe, a nitrification liquid circulation pipe and a backwash pipe connected to the second booster pump; one end of the mud discharge main pipe is connected to the first mud discharge branch pipe and the second mud discharge branch pipe, and a mud discharge valve is arranged on the mud discharge main pipe; one end of the nitrification liquid circulation pipe is connected to the first nitrification liquid circulation branch pipe and the second nitrification liquid circulation branch pipe, and the other end is connected to the first circulation main pipe and the second circulation main pipe.

[0013] Preferably, the aerobic treatment unit comprises an activated sludge tank, a secondary sedimentation tank, a BAF tank and a multi-media filter which are connected in sequence; a return pipe is arranged at the bottom of the secondary sedimentation tank, and the other end of the return pipe is connected to the activated sludge tank.

[0014] Preferably, a plurality of iron-based plates are evenly arranged in the electrolytic cell.

[0015] Preferably, the inter-electrode distance between the iron-based plates is 20-25 mm.

[0016] Preferably, the ozone deep oxidation denitrification unit comprises a plurality of oxidation towers connected in series, and a microporous aerator is arranged at the bottom of the oxidation tower.

[0017] A method for treating nitramine explosive wastewater comprises the following steps:

[0018] (1) Wastewater homogenization and regulation: Collect wastewater of different concentrations and components in the synthesis process in the regulating tank to meet the basic requirements of stable water quality indicators in subsequent processes, such as COD < 10,000 mg / l, main pollutants nitramines < 150 mg / l, nitrobenzene < 300 mg / l, and acidity < 1.0%;

[0019] (2) The homogenized wastewater is pumped to the pre-oxidation tank, and sodium hypochlorite and hydrogen peroxide are added to perform preliminary degradation and modification of pollutants. After 2 hours of microporous aeration, the wastewater flows by gravity to the water inlet distribution pipe of the electrolytic cell, and enters the electrolytic cell through the water distribution branch pipe on the water inlet distribution pipe. The pre-oxidation effluent achieves COD < 8000 mg / L. Although the concentration of characteristic pollution factors has not been significantly reduced, the oxidant has modified the pollutants and formed a homogeneous oxidant system, creating conditions for further electrical coupling and subsequent treatment.

[0020] (3) The wastewater entering the electrolytic cell must have a residence time (HRT) of no less than 1 hour. The working principle of electrochemical coupling is to use a DC power supply and an iron-based electrode. Under the current impact and electrocatalysis in the electric field, the organic matter in the wastewater produces an instantaneous electrochemical reaction on the electrode surface, which can not only dissolve Fe 2+ , and can also reduce and modify organic matter; anode electrolysis produces active Fe 2+ , can immediately complex with organic matter in wastewater, reduce hydrogen ions or organic pollutants by cathode electrolysis, and modify organic pollutants; Fe 2+ The organic matter is rapidly degraded and mineralized by the Fenton reaction with H2O2; at the same time, the strong oxidizing property of sodium hypochlorite oxidizes and modifies the intermediate products in the electrolysis process, and the electrochemical coupling effluent meets the requirements of COD < 3000mg / l, main pollutants nitramines < 30mg / l, and nitrobenzene < 20mg / l;

[0021] (4) The effluent from the electrolytic cell enters the first water inlet pipe of the plug-flow internal circulation anaerobic reaction device after sedimentation; the plug-flow internal circulation anaerobic reaction device is a two-stage series mode, the first stage is the anaerobic sludge reaction zone, which has a higher tolerance. An inclined tube separation layer is set in the anaerobic sludge reaction zone, and the first water distribution branch pipe at the bottom of the sludge layer is connected to the first circulation pipe. The high reflux ratio determines that the anaerobic sludge reaction zone can maintain a high sludge content; the second stage is the anaerobic filler reaction zone, and the biochemical method is used to treat nitro compound wastewater, which can remove more than 70% of CO, with a high removal rate; when only a small amount of nutrients is added to the wastewater, the organic pollutants in the wastewater are biologically converted into carbon dioxide and water, realizing the economic removal of pollutants; the plug-flow internal circulation anaerobic reaction device is a medium-temperature reactor, and the first-stage anaerobic sludge reaction zone is connected to the circulation unit. The second-stage anaerobic filler reaction zone is connected to the circulation unit, and is equipped with a microbial or bio-enzyme inoculation pipeline, which can directly transport high-efficiency microorganisms to the bottom of the anaerobic filler reaction zone, and complete the expansion by attaching to the filler in the filler layer during the upflow process, and perform adaptive cultivation through the circulation unit. The expansion and adaptive cultivation of the system strains can be completed in 1-2 weeks, which greatly shortens the system startup time. The effluent of the plug-flow anaerobic reaction device meets the requirements of COD < 500mg / l in wastewater, and the main pollutants nitramines < 5mg / l and nitrobenzene < 5mg / l.

[0022] (5) The effluent from the plug-flow internal circulation anaerobic reaction device flows into the activated sludge tank for aerobic metabolism; powdered activated carbon (PAC) is added to the activated sludge tank to enhance the activated sludge function. The effluent from the activated sludge tank meets the requirements of COD < 100 mg / l, main pollutants nitramines < 2 mg / l, and nitrobenzene < 1 mg / l;

[0023] (6) The effluent from the activated sludge tank flows into the secondary sedimentation tank for mud-water separation, and the settled sludge is continuously returned to the activated sludge tank. The suspended solids in the effluent are controlled to be less than 100 mg / l, and the effluent flows into the BAF tank to remove ammonia nitrogen;

[0024] (7) The effluent from the BAF tank is pumped to a multi-media filter to remove particles, suspended matter and colloids;

[0025] (8) The effluent from the multi-media filter enters the ozone deep oxidation denitrification unit. The oxidation tower in the ozone deep oxidation denitrification unit adopts a multi-tower series process. After passing through the distributor, the ozone enters the microporous aerator at the bottom of the oxidation tower for distribution. The ozone concentration is not less than 20 mg / l. The water inlet pipe of the first oxidation tower is equipped with a dosing pipeline for adding sodium hypochlorite and denitrification agent. Sodium hypochlorite and denitrification agent are pumped into the first oxidation tower together with the inlet water. After the wastewater is deeply oxidized and denitrified by multiple towers in series, it passes through the terminal liquid seal device and meets the discharge standards.

[0026] The beneficial effects of the present invention are:

[0027] First: The front-end electrochemical coupling technology has strong adaptability, high pollutant removal rate, and significant reduction in wastewater toxicity. It can ensure a stable low concentration of organic load in the biochemical system and is a safety barrier for the biochemical system. It also has convenient and reliable processing capabilities and adjustment functions. The adjustment method can be achieved by adjusting the current of the DC power supply that supplies it. Organic matter is rapidly degraded and mineralized. The simultaneous addition of sodium hypochlorite and hydrogen peroxide improves the modification of pollutants in the electrolysis process, which is beneficial to the formation of complex products and helps Fenton. At the same time, the high adsorption of iron hydroxide has high adsorption to complexes. The electrochemical coupling unit can change the system water volume according to the number of devices invested, and has flexible scalability.

[0028] Second: The plug-flow internal circulation anaerobic reaction device is the most economical wastewater treatment method. Its unique internal circulation pipeline and internal structure ensure the rapid inoculation and expansion of microorganisms in the two-stage reactor. The adjustment function of the internal circulation variable flow can accelerate the adaptive cultivation of the system. The expansion and adaptive cultivation of the system can be completed in 1-2 weeks, which greatly shortens the system startup time. The entire commissioning period of the traditional anaerobic reactor takes about 2-3 months.

[0029] Third: The plug-flow internal circulation anaerobic reaction device is a two-stage series mode with strong operability. It can not only accelerate the cultivation and debugging, but also has the function of sludge discharge. The first stage of the reaction device is the anaerobic sludge reaction zone, which has high tolerance. The variable flow internal circulation structure creates an environment suitable for the survival of microorganisms and is conducive to the formation of granular sludge. An inclined tube separation zone is set in the sludge zone, and the mud-water separation effect is good. The second stage of the reaction device is the anaerobic filler reaction zone. The polyurethane filler layer is used to ensure that the anaerobic effluent has low suspended solids, and the COD removal is greater than 80%, with a high removal rate. The use of biochemical treatment as the main process for treating nitro compound wastewater is to give full play to this excellent feature of biological treatment, and use biological methods to economically remove most of the pollutants in the wastewater, significantly reducing the load of physical and chemical treatment and the consumption of drugs involved in physical and chemical treatment; accordingly, the operating cost of nitro compound wastewater treatment is reduced, making the entire treatment plan more economical.

[0030] Fourth: Powdered activated carbon (PAC) is added to the activated sludge tank to enhance the activated sludge function. The stability and reliability are better than other activated sludge methods and can fully adapt to large load changes;

[0031] Fifth: The ozone deep oxidation denitrification unit adopts a multi-tower series process. The simultaneous action of sodium hypochlorite, denitrifier, hydrogen peroxide and other agents and ozone ensures that the terminal effluent is stable and meets the standards. The terminal liquid seal device ensures that the ozone in the tower does not leak out, ensuring safe operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the present invention.

[0033] Figure 2 This is a schematic diagram of the structure of a plug-flow internal circulation anaerobic reaction device.

[0034] Figure 3 This is a schematic diagram of the structure of the first water distribution branch pipe at the bottom of the anaerobic sludge reaction zone.

[0035] Figure 4 This is a schematic diagram of the second water distribution branch structure at the bottom of the anaerobic filler reaction zone.

[0036] Figure 5 This is a schematic diagram of the structure of the first water collection tank.

[0037] In the figure: 10 is a regulating tank, 20 is a pre-oxidation tank, 30 is an electrolytic cell, 31 is an iron-based plate, 40 is a plug-flow internal circulation anaerobic reaction device, 41 is an anaerobic sludge reaction zone, 41.1 is a sludge layer, 41.2 is a static separation layer, 41.3 is an inclined tube separation layer, 41.4 is a first water collection tank, 41.5 is a first water distribution branch pipe, 41.5a is a first water inlet valve, 41.5b is a second water inlet valve, 41.6 is a first sludge discharge branch pipe, 41.7 is a first nitrification liquid circulation branch pipe, 41.8 is a first water inlet pipe, 41.9 is a first circulation main pipe, 42 is an anaerobic filler reaction zone, 42.1 is a filler layer, 42.2 is a second water collection tank, 42.3 is a second water distribution branch pipe, 42.3a is a third water inlet valve, 42.3b is a fourth water inlet valve, 42. 4 is the second sludge discharge branch pipe, 42.5 is the second nitrification liquid circulation branch pipe, 42.6 is the second water inlet pipe, 42.7 is the second circulation main pipe, 43 is the circulation unit, 43.1 is the second booster pump, 43.2 is the sludge discharge main pipe, 43.3 is the nitrification liquid circulation pipe, 43.4 is the sludge discharge valve, 43.5 is the backwash pipe, 44 is the remote level gauge, 45 is the booster unit, 45.1 is the first connecting pipe, 45.2 is the second connecting pipe, 45.3 is the parallel valve, 45.4 is the first booster pump, 45.5 is the inlet valve, 45.6 is the outlet valve, 50 is the aerobic treatment unit, 51 is the activated sludge tank, 52 is the second sedimentation tank, 52.1 is the reflux pipe, 53 is the BAF tank, 54 is the multi-media filter, 60 is the ozone deep oxidation denitrification unit, and 61 is the oxidation tower. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings.

[0039] A nitramine explosive wastewater treatment device comprises a regulating tank 10, a pre-oxidation tank 20, an electrolytic cell 30, a plug-flow internal circulation anaerobic reaction device 40, an aerobic treatment unit 50 and an ozone deep oxidation denitrification unit 60 which are connected in sequence; the plug-flow internal circulation anaerobic reaction device 40 comprises an anaerobic sludge reaction zone 41 and an anaerobic filler reaction zone 42 which are connected in sequence.

[0040] Preferably, in the anaerobic sludge reaction zone 41, from bottom to top, there are a sludge layer 41.1, a static separation layer 41.2, an inclined tube separation layer 41.3, and a first water collection tank 41.4 in sequence; inclined tube separation fillers are arranged in the inclined tube separation layer 41.3; the first water collection tank 41.4 is in a "rich" shape; a first water distribution branch pipe 41.5 is arranged at the bottom of the sludge layer 41.1, and a first sludge discharge branch pipe 41.6 is arranged above the first water distribution branch pipe 41.5; a first nitrification liquid circulation branch pipe 41.7 is arranged at the top of the sludge layer 41.1; one end of the first water distribution branch pipe 41.5 is connected to a first water inlet pipe 41.8, and the other end is connected to a first circulation main pipe 41.9; a first water inlet valve 41.5a is arranged on one side of the first water distribution branch pipe 41.5 close to the first water inlet pipe 41.8, and a second water inlet valve 41.5b is arranged on the side close to the first circulation main pipe 41.9; the first sludge discharge branch pipe 41.6, the first nitrification liquid circulation branch pipe 41.7, and the first circulation main pipe 41.9 are all connected to a circulation unit 43, a remote transmission liquid level gauge 44 is arranged in the first water collection tank 41.4, and an interlock is formed between the first water inlet valve 41.5a and the second water inlet valve 41.5b. The interlock principle is that when the first water inlet valve 41.5a on a certain first water distribution branch pipe 41.5 is closed, the corresponding second water inlet valve 41.5b is opened. The 10 branch pipes are operated in sequence. That is to say, 5 branch pipes are in operation for water inlet, and 5 branch pipes are in operation for circulating water distribution. By alternating operation, the position transformation of water inlet and circulating water distribution is realized. The multi-point water inlet of the transformation ensures a homogeneous environment in the reactor, is suitable for domestication and cultivation of adapted microbial communities, can give full play to the functions of each reaction system, and avoids the simplification of the functions of the reaction system.

[0041] Preferably, a packing layer 42.1 (the packing can be polyurethane packing) is arranged in the anaerobic packing reaction zone 42, and a second water collection tank 42.2 is arranged above the packing layer 42.1; the second water collection tank 42.2 is in a "rich" shape; the structure is the same as that of the first water collection tank 41.4; a second water distribution branch pipe 42.3 is arranged below the packing layer 42.1, and a second sludge discharge branch pipe 42.4 is arranged above the second water distribution branch pipe 42.3; a second nitrification liquid circulation branch pipe 42.5 is arranged above the packing layer 42.1; one end of the second water distribution branch pipe 42.3 is connected to a second water inlet pipe 42.6, and the other end is connected to a second circulation main pipe 42.7; a third water inlet valve 42.3a is arranged on one side of the second water distribution branch pipe 42.3 close to the second water inlet pipe 42.6, and a fourth water inlet valve 42.3b is arranged on the side close to the second circulation main pipe 42.7; the second sludge discharge branch pipe 42.4, the second nitrification liquid circulation branch pipe 42.5, and the second circulation main pipe 42.7 are all connected to the circulation unit 43; an interlock is formed between the third water inlet valve 42.3a and the fourth water inlet valve 42.3b. The interlock principle is similar to that between the first water inlet valve 41.5a and the second water inlet valve 41.5b, and will not be elaborated here.

[0042] Preferably, a booster unit 45 is further arranged between the anaerobic sludge reaction zone 41 and the anaerobic filler reaction zone 42; the booster unit 45 comprises a first connecting pipe 45.1 and a second connecting pipe 45.2, both of which are connected to the first water collecting tank 41.4 and the second water inlet pipe 42.6; a parallel valve 45.3 is arranged on the first connecting pipe 45.1, a first booster pump 45.4 is arranged on the second connecting pipe 45.2, an inlet valve 45.5 is arranged on the side of the second connecting pipe 45.2 close to the first water collecting tank 41.4, and a second booster pump 45.4 is arranged on the side of the second connecting pipe 45.2 close to the second water inlet An outlet valve 45.6 is provided on one side of the pipe 42.6; an interlock is formed between the parallel valve 45.3, the first booster pump 45.4, the inlet valve 45.5, the outlet valve 45.6 and the remote level meter 44; the specific interlock relationship is: when the liquid level in the anaerobic sludge reaction zone 41 is high, the parallel valve 45.3 is closed, the inlet valve 45.5 is opened, the first booster pump 45.4 is turned on, and the outlet valve 45.6 is opened to complete drainage; when the liquid level is low, the outlet valve 45.6 is closed, the first booster pump 45.4 is stopped, the inlet valve 45.5 is closed, the parallel valve 45.3 is opened, and the water flows into the second water inlet pipe 42.6.

[0043] Preferably, the circulation unit 43 comprises a second booster pump 43.1 and a mud discharge main pipe 43.2, a nitrification liquid circulation pipe 43.3 and a backwash pipe 43.5 connected to the second booster pump 43.1; one end of the mud discharge main pipe 43.2 is connected to the first mud discharge branch pipe 41.6 and the second mud discharge branch pipe 42.4, and a mud discharge valve 43.4 is arranged on the mud discharge main pipe 43.2; one end of the nitrification liquid circulation pipe 43.3 is connected to the first nitrification liquid circulation branch pipe 41.7 and the second nitrification liquid circulation branch pipe 42.5, and the other end is connected to the first circulation main pipe 41.9 and the second circulation main pipe 42.7.

[0044] Preferably, the aerobic treatment unit 50 comprises an activated sludge tank 51 , a secondary sedimentation tank 52 , a BAF tank 53 and a multi-media filter 54 which are connected in sequence; a return pipe 52 . 1 is arranged at the bottom of the secondary sedimentation tank 52 , and the other end of the return pipe 52 . 1 is connected to the activated sludge tank 51 .

[0045] Preferably, a plurality of iron-based electrode plates 31 are evenly arranged in the electrolytic cell 30 , and the number of the iron-based electrode plates 31 can be determined according to the size of the electrolytic cell 30 .

[0046] Preferably, the inter-electrode distance between the iron-based plates 30 is 20-25 mm.

[0047] Preferably, the ozone deep oxidation denitrification unit 60 comprises a plurality of oxidation towers 61 connected in series, and a microporous aerator (not shown in the figure) is disposed at the bottom of the oxidation tower 61 .

[0048] A method for treating nitramine explosive wastewater comprises the following steps:

[0049] (1) Wastewater homogenization and regulation: wastewater of different concentrations and components in the synthesis process is collected in the regulating tank 10 to meet the basic requirements of stable water quality indicators in subsequent processes, such as COD < 10,000 mg / l, main pollutants nitramines < 150 mg / l, nitrobenzene < 300 mg / l, and acidity < 1.0%;

[0050] (2) The homogenized wastewater is pumped to the pre-oxidation tank 20, and sodium hypochlorite and hydrogen peroxide are added to perform preliminary degradation and modification of the pollutants. The wastewater is then aerated for 2 hours and flows by gravity to the water inlet distribution pipe of the electrolytic cell 30, and then enters the electrolytic cell 30 through the water distribution branch pipe on the water inlet distribution pipe. The pre-oxidation effluent achieves COD < 8000 mg / L. Although the concentration of the characteristic pollution factor is not significantly reduced, the pollutants are modified by the action of the oxidant, and a homogeneous oxidant system is formed, creating conditions for further electrical coupling and subsequent treatment.

[0051] (3) The wastewater entering the electrolytic cell 30 ensures that the residence time (HRT) is not less than 1 hour. The working principle of electrochemical coupling is to use a DC power supply and an iron-based electrode 31. Under the current impact and electrocatalytic action in the electric field, the organic matter in the wastewater produces an instantaneous electrochemical reaction on the electrode surface, which can not only dissolve Fe 2+ , and can also reduce and modify organic matter; anode electrolysis produces active Fe 2+ , can immediately complex with organic matter in wastewater, reduce hydrogen ions or organic pollutants by cathode electrolysis, and modify organic pollutants; Fe 2+ The organic matter is rapidly degraded and mineralized by the Fenton reaction with H2O2; at the same time, the strong oxidizing property of sodium hypochlorite oxidizes and modifies the intermediate products in the electrolysis process, and the electrochemical coupling effluent meets the requirements of COD < 3000mg / l, main pollutants nitramines < 30mg / l, and nitrobenzene < 20mg / l;

[0052] (4) The effluent from the electrolytic cell 30 enters the first water inlet pipe 41.8 of the plug-flow internal circulation anaerobic reaction device 40 after sedimentation; the plug-flow internal circulation anaerobic reaction device 40 is a two-stage series mode, the first stage is the anaerobic sludge reaction zone 41, which has a higher tolerance. An inclined tube separation layer 41.3 is arranged in the anaerobic sludge reaction zone 41, and the first water distribution branch pipe 42.3 at the bottom of the sludge layer 41.1 is also connected to the first circulation pipe 41.9. The high reflux ratio determines that the anaerobic sludge reaction zone 41 can maintain a higher sludge content; the second stage is the anaerobic filler reaction zone Zone 42, biochemical treatment of nitro compound wastewater can remove more than 70% of CO, with a high removal rate; when only a small amount of nutrient salt is added to the wastewater, the organic pollutants in the wastewater are biologically converted into carbon dioxide and water, achieving economical removal of pollutants; using biochemical treatment as the main process for treating nitro compound wastewater is to give full play to this excellent feature of biological treatment, and use biological methods to economically remove most of the pollutants in the wastewater, significantly reducing the load of physicochemical treatment and the consumption of drugs involved in physicochemical treatment; accordingly, the operating cost of nitro compound wastewater treatment is reduced, making the entire treatment plan more economical; the plug flow internal circulation anaerobic reaction device 40 is a medium temperature reactor, the first stage anaerobic sludge reaction zone 41 is connected to the circulation unit 43, and has the function of facilitating sludge inoculation, the inoculation amount is 10-20% of the volume of the anaerobic sludge reaction zone 41, and a small amount of water can be introduced while inoculating. After the anaerobic sludge reaction zone 41 is filled with liquid, the pH value is adjusted, and reflux stirring and expansion are started, and the water intake is gradually increased; the second stage anaerobic filler reaction zone 42 Connected to the circulation unit 43, equipped with a microorganism or bio-enzyme inoculation pipeline, the efficient microorganisms can be directly transported to the bottom of the anaerobic packing reaction zone 42, and attached to the packing in the packing layer 42.1 during the upflow process to complete the expansion, and adaptive cultivation is carried out through the circulation unit. The expansion and adaptive cultivation of the system strains can be completed in 1-2 weeks, which greatly shortens the system startup time. The effluent of the plug-flow anaerobic reaction device meets the requirements of COD < 500mg / l in wastewater, and the main pollutants nitramines < 5mg / l and nitrobenzene < 5mg / l;

[0053] (5) The effluent of the plug-flow internal circulation anaerobic reaction device 40 flows into the activated sludge tank 51 for aerobic metabolism; powdered activated carbon (PAC) is added to the activated sludge tank 51 to enhance the activated sludge function, and the effluent of the activated sludge tank 51 satisfies the requirements of COD < 100 mg / l, and the main pollutants nitramines < 2 mg / l and nitrobenzene < 1 mg / l in the wastewater;

[0054] (6) The effluent from the activated sludge tank 51 flows into the secondary sedimentation tank 52 for mud-water separation, and the settled sludge is continuously returned to the activated sludge tank 51. The suspended solids in the effluent are controlled to be less than 100 mg / l, and the effluent flows into the BAF tank 53 by gravity to remove ammonia nitrogen;

[0055] (7) The effluent from the BAF tank 53 is pumped to the multi-media filter 54 to filter and remove particles, suspended matter and colloids;

[0056] (8) The effluent from the multi-media filter 54 enters the ozone deep oxidation denitrification unit 60. The oxidation tower 61 in the ozone deep oxidation denitrification unit 60 adopts a multi-tower series process. After passing through a distributor, ozone enters the microporous aerator at the bottom of the oxidation tower 61 for distribution. The ozone concentration is not less than 20 mg / l. The water inlet pipe of the first oxidation tower 61 is equipped with a dosing pipeline for adding sodium hypochlorite and denitrification agent. Sodium hypochlorite and denitrification agent are pumped into the first oxidation tower 61 together with the inlet water. After the wastewater is subjected to multi-tower series deep oxidation denitrification, it passes through the terminal liquid seal device and meets the discharge standards.

[0057] The present invention adopts a combined technology of pre-electrochemical coupling pretreatment technology combined with a plug-flow internal circulation anaerobic reaction device, an activated sludge enhancement process and an ozone deep oxidation post-treatment technology. The method has low treatment cost, good mud-water separation effect, and can achieve stable and standard discharge of nitramine explosive wastewater.

[0058] The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A nitramine explosive wastewater treatment device, characterized in that: The invention comprises a regulating tank (10), a pre-oxidation tank (20), an electrolytic cell (30), a plug-flow internal circulation anaerobic reaction device (40), an aerobic treatment unit (50) and an ozone deep oxidation denitrification unit (60) which are connected in sequence; the plug-flow internal circulation anaerobic reaction device (40) comprises an anaerobic sludge reaction zone (41) and an anaerobic filler reaction zone (42) which are connected in sequence; the anaerobic sludge reaction zone (41) comprises a sludge layer (41.1), a static separation layer (41.2), an inclined tube separation layer (41.3) and a first water collecting tank (41.4) from bottom to top; a first water distribution branch pipe (41.5) is arranged at the bottom of the sludge layer (41.1), and a first sludge discharge branch pipe (41.5) is arranged above the first water distribution branch pipe (41.5). pipe (41.6); a first nitrification liquid circulation branch pipe (41.7) is arranged on the top of the sludge layer (41.1); one end of the first water distribution branch pipe (41.5) is connected to the first water inlet pipe (41.8), and the other end is connected to the first circulation main pipe (41.9); a first water inlet valve (41.5a) is arranged on the side of the first water distribution branch pipe (41.5) close to the first water inlet pipe (41.8), and a second water inlet valve (41.5b) is arranged on the side close to the first circulation main pipe (41.9); the first sludge discharge branch pipe (41.6), the first nitrification liquid circulation branch pipe (41.7) and the first circulation main pipe (41.9) are all connected to the circulation unit (43); a remote liquid level transmitter is arranged in the first water collecting tank (41.4) The first water inlet valve (41.5a) and the second water inlet valve (41.5b) are interlocked. The interlocking principle is that when the first water inlet valve on a first water distribution branch pipe is closed, the corresponding second water inlet valve is opened. The alternating operation realizes the position change of water distribution and circulating water distribution. The changed multi-point water inlet ensures a homogeneous environment in the reactor, which is suitable for domesticating and cultivating an adaptive microbial community. A packing layer (42.1) is arranged in the anaerobic packing reaction zone (42), and a second water collecting tank (42.2) is arranged above the packing layer (42.1); a second water distribution branch pipe (42.3) is arranged below the packing layer (42.1), and a second mud discharge branch pipe (42.3) is arranged above the second water distribution branch pipe (42.3). .4); a second nitrification liquid circulation branch pipe (42.5) is arranged above the packing layer (42.1); one end of the second water distribution branch pipe (42.3) is connected to the second water inlet pipe (42.6), and the other end is connected to the second circulation main pipe (42.7); a third water inlet valve (42.3a) is arranged on the side of the second water distribution branch pipe (42.3) close to the second water inlet pipe (42.6), and a fourth water inlet valve (42.3b) is arranged on the side close to the second circulation main pipe (42.7); the second mud discharge branch pipe (42.4), the second nitrification liquid circulation branch pipe (42.5) and the second circulation main pipe (42.7) are all connected to the circulation unit (43), and the third water inlet valve (42.3a) and the fourth water inlet valve (42.3b) form an interlock, and the interlocking principle is the same as that of the first water inlet valve and the second water inlet valve; a plurality of iron-based plates (31) are evenly arranged in the electrolytic cell (30).

2. A nitramine explosive wastewater treatment device according to claim 1, characterized in that: A booster unit (45) is also provided between the anaerobic sludge reaction zone (41) and the anaerobic filler reaction zone (42); the booster unit (45) comprises a first connecting pipe (45.1) and a second connecting pipe (45.2); the first connecting pipe (45.1) and the second connecting pipe (45.2) are both connected to a first water collecting tank (41.4) and a second water inlet pipe (42.6); a parallel valve (45.3) is provided on the first connecting pipe (45.1), a first booster pump (45.4) is provided on the second connecting pipe (45.2), an inlet valve (45.5) is provided on a side of the second connecting pipe (45.2) close to the first water collecting tank (41.4), and an outlet valve (45.6) is provided on a side of the second connecting pipe (45.2) close to the second water inlet pipe (42.6); an interlock is formed between the parallel valve (45.3), the first booster pump (45.4), the inlet valve (45.5), the outlet valve (45.6) and the remote level meter (44).

3. A nitramine explosive wastewater treatment device according to claim 1, characterized in that: The circulation unit (43) comprises a second booster pump (43.1) and a mud discharge main pipe (43.2) connected to the second booster pump (43.1), a nitrification liquid circulation pipe (43.3) and a backwash pipe (43.5); one end of the mud discharge main pipe (43.2) is connected to the first mud discharge branch pipe (41.6) and the second mud discharge branch pipe (42.4), and a mud discharge valve (43.4) is arranged on the mud discharge main pipe (43.2); one end of the nitrification liquid circulation pipe (43.3) is connected to the first nitrification liquid circulation branch pipe (41.7) and the second nitrification liquid circulation branch pipe (42.5), and the other end is connected to the first circulation main pipe (41.9) and the second circulation main pipe (42.7).

4. A nitramine explosive wastewater treatment device according to claim 1, characterized in that: The aerobic treatment unit (50) comprises an activated sludge tank (51), a secondary sedimentation tank (52), a BAF tank (53) and a multi-media filter (54) which are connected in sequence; a return pipe (52.1) is provided at the bottom of the secondary sedimentation tank (52), and the other end of the return pipe (52.1) is connected to the activated sludge tank (51).

5. A nitramine explosive wastewater treatment device according to claim 1, characterized in that: The inter-electrode distance of the iron-based electrode plates (31) is 20-25 mm.

6. A nitramine explosive wastewater treatment device according to claim 1, characterized in that: The ozone deep oxidation denitrification unit (60) comprises a plurality of oxidation towers (61) connected in series, and a microporous aerator is arranged at the bottom of the oxidation tower (61).

7. A method for treating wastewater from a nitramine explosive wastewater treatment plant according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Wastewater homogenization and regulation: wastewater of different concentrations and components in the synthesis process is collected in the regulating tank (10) to meet the basic requirements of stable water quality indicators in subsequent processes, such as COD < 10,000 mg / L, major pollutants such as nitramines < 150 mg / L, nitrobenzene < 300 mg / L, and acidity < 1.0%; (2) The homogenized wastewater is pumped to the pre-oxidation tank (20), and sodium hypochlorite and hydrogen peroxide are added to perform preliminary degradation and modification of the pollutants. The wastewater is then aerated for 2 hours and flows by gravity to the water inlet distribution pipe of the electrolytic cell (30), and then enters the electrolytic cell (30) through the water distribution branch pipe on the water inlet distribution pipe. The pre-oxidation effluent achieves a COD of less than 8000 mg / L in the wastewater. The pollutants are modified by the oxidant, and a homogeneous oxidant system is formed, creating conditions for further electrical coupling and subsequent treatment. (3) The wastewater entering the electrolytic cell (30) is ensured to stay for no less than 1 hour. The working principle of electrochemical coupling is to use a DC power supply and an iron-based electrode plate (31). Under the current impact and electrocatalytic action in the electric field, the organic matter in the wastewater produces an instantaneous electrochemical reaction on the electrode surface, which can not only dissolve Fe 2+ , and can also reduce and modify organic matter; Anodic electrolysis produces active Fe 2+ , can complex with organic matter in wastewater, reduce hydrogen ions or organic pollutants by cathode electrolysis, and modify organic pollutants; Fe 2+ The organic matter is rapidly degraded and mineralized by the Fenton reaction with H2O2. At the same time, the strong oxidizing property of sodium hypochlorite oxidizes and modifies the intermediate products in the electrolysis process. The electrochemically coupled effluent meets the requirements of COD < 3000 mg / L in wastewater, nitramines of major pollutants < 30 mg / L, and nitrobenzene < 20 mg / L. (4) The effluent from the electrolytic cell (30) enters the first water inlet pipe (41.8) of the plug-flow internal circulation anaerobic reaction device (40) after sedimentation; the plug-flow internal circulation anaerobic reaction device (40) is a two-stage series mode, the first stage is an anaerobic sludge reaction zone (41), an inclined tube separation layer (41.3) is arranged in the anaerobic sludge reaction zone (41), the first water distribution branch pipe (41.5) at the bottom of the sludge layer (41.1) is connected to the first circulation pipe (41.9), and the high reflux ratio determines that the anaerobic sludge reaction zone (41) can maintain a high sludge content; the second stage is an anaerobic filler reaction zone (42), and the biochemical method is used to treat the nitro compound wastewater, which can remove more than 70% of the wastewater COD and has a high removal rate; when only a small amount of nutrient salt is added to the wastewater, the organic pollutants in the wastewater are biologically converted into carbon dioxide and water, thereby achieving economical removal of pollutants; the plug-flow internal circulation anaerobic reaction device (4 0) is a medium-temperature reactor. The anaerobic sludge reaction zone (41) is connected to the circulation unit (43) and has the function of facilitating sludge inoculation. The inoculation amount is 10-20% of the volume of the anaerobic sludge reaction zone (41). It can realize a small amount of water intake while inoculating. After the anaerobic sludge reaction zone (41) is filled with liquid, the pH value is adjusted, and reflux stirring and expansion cultivation is started, and the water intake is gradually increased; the anaerobic filler reaction zone (42) is connected to the circulation unit (43), and a microorganism or biological enzyme inoculation pipeline is configured. High-efficiency microorganisms can be directly transported to the bottom of the anaerobic filler reaction zone (42), and attached to the filler in the filler layer (42.1) during the upflow process to complete the expansion cultivation, and adaptive cultivation is carried out through the circulation unit (43). The expansion cultivation and adaptive cultivation of the system strains can be completed in 1-2 weeks, shortening the system startup time. The effluent of the plug-flow internal circulation anaerobic reaction device (40) meets the COD of the wastewater <500. mg / L, the main pollutants nitramines <5mg / L, nitrobenzene <5mg / L; (5) The effluent of the plug-flow internal circulation anaerobic reaction device (40) flows into the activated sludge tank (51) for aerobic metabolism; powdered activated carbon is added to the activated sludge tank (51) to enhance the activated sludge function, and the effluent of the activated sludge tank (51) satisfies the requirements of COD < 100 mg / L, and the main pollutants nitramines < 2 mg / L, and nitrobenzene < 1 mg / L; (6) The effluent from the activated sludge tank (51) flows into the secondary sedimentation tank (52) for mud-water separation, and the settled sludge is continuously returned to the activated sludge tank (51). The suspended solids in the effluent are controlled to be less than 100 mg / L, and the effluent flows into the BAF tank (53) by gravity to remove ammonia nitrogen; (7) The effluent from the BAF tank (53) is pumped to a multi-media filter (54) to filter and remove particles, suspended matter and colloids; (8) The effluent from the multi-media filter (54) enters the ozone deep oxidation denitrification unit (60). The oxidation tower (61) in the ozone deep oxidation denitrification unit (60) adopts a multi-tower series process. Ozone passes through a distributor and enters the microporous aerator at the bottom of the oxidation tower (61) for distribution. The ozone concentration is not less than 20 mg / L. The water inlet pipe of the first oxidation tower (61) is equipped with a dosing pipeline for adding sodium hypochlorite and denitrifier. The sodium hypochlorite and denitrifier are pumped together with the water into the first oxidation tower (61). After the wastewater is subjected to multi-tower series deep oxidation denitrification, it passes through the terminal liquid seal device and meets the discharge standards.

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