A device and method for treating organophosphorus pesticide wastewater based on "EGSB+biological contact oxidation+Fenton method"

Abstract

A device and method for treating organophosphorus pesticide wastewater based on "EGSB+biological contact oxidation+Fenton method" relates to a wastewater treatment method. It is to solve the technical problems of high difficulty, high investment and high operating cost in the existing organophosphorus pesticide wastewater treatment. The device includes an inlet water tank, an inlet water pump, an anaerobic reactor, a heating pump, a constant temperature water bath, a reflux pump, a biological contact oxidation tank, and a Fenton oxidizer; the inlet water tank is connected to the anaerobic reactor through the inlet water pump; the anaerobic reactor is provided with a heating jacket and a reflux pipe; the outlet of the anaerobic reactor is connected to the biological contact oxidation tank and the Fenton oxidizer in sequence. Method: 1. Start the device with simulated organophosphorus pesticide wastewater, and 2. Stable operation. After the organophosphorus pesticide wastewater is treated, the removal rates of COD, total phosphorus, organic phosphorus and phosphate exceed 99.7%, 97.6%, 99.5% and 94.1% respectively. It can be used in the field of wastewater treatment.

Description

Technical Field

[0001] The invention relates to a method for treating an organophosphorus pesticide and belongs to the field of industrial wastewater treatment. Background Art

[0002] Organophosphorus pesticides are widely used in farmland pest control due to their significant insecticidal effects, broad insecticidal spectrum, wide variety, low price, easy decomposition, wide application, and low resistance. Organophosphorus pesticides belong to phosphate organic compounds, such as methyl parathion, phosalone, dichlorvos, dimethoate, methyl parathion, malathion, etc. However, organophosphorus pesticide wastewater is produced during the production and use of organophosphorus pesticides. This type of pesticide wastewater has complex components, high toxicity, high concentration, many difficult-to-degrade organic components, and poor biodegradability. Its main component, organophosphorus, is a neurotoxin that inhibits the activity of acetylcholinesterase in the blood and tissues, causing a large accumulation of acetylcholine, blocking nerve conduction, and finally leading to central nervous system poisoning. Mild cases cause headaches, dizziness, nausea, and severe cases cause muscle cramps, respiratory paralysis, and death. The main characteristics of organophosphorus pesticides are: 1) high concentration of pollutants, COD can reach tens of thousands of milligrams per liter; 2) high toxicity, in addition to pesticides and pesticide intermediates, wastewater also contains phenols, arsenic, mercury and other toxic substances and many substances that are difficult to degrade by organisms; 3) malodor, irritating to human respiratory tract and mucous membranes; 4) unstable water quality and water volume. Therefore, organophosphorus pesticide wastewater is very polluting to the environment.

[0003] At present, the main treatment methods for organophosphorus pesticide wastewater are biological methods, such as anaerobic method and aerobic method; and physical and chemical methods, such as membrane separation, evaporation separation, advanced oxidation, incineration, etc. The biological method has low cost, but it is difficult to treat organophosphorus wastewater to meet the standards; although the physical and chemical method has a good treatment effect on organophosphorus wastewater, the investment cost and operating cost are relatively high. Therefore, it is urgent to develop new technologies for the treatment of organophosphorus pesticide wastewater with good treatment effect, low investment and low operating cost. Summary of the invention

[0004] The present invention aims to solve the technical problems of the existing organophosphorus pesticide wastewater treatment being difficult, requiring high investment, high operating cost, and difficulty in achieving effluent standards, and to provide an organophosphorus pesticide wastewater treatment method.

[0005] The device for treating organophosphorus pesticide wastewater based on "EGSB+biological contact oxidation+Fenton method" of the present invention comprises a water inlet tank, a water inlet pump, an anaerobic reactor, a heating pump, a constant temperature water bath, a reflux pump, a biological contact oxidation tank, and a Fenton oxidizer;

[0006] The anaerobic reactor has a water inlet at the bottom, a water outlet at the top side, a jacket at the outer wall of the anaerobic reactor, an inlet and an outlet at the jacket, and a reflux water outlet at the middle and upper part of the anaerobic reactor;

[0007] The inlet water tank is connected to the water inlet of the anaerobic reactor through the inlet pump; the reflux water outlet is connected to the front end water pipe of the inlet pump through the reflux pump; the jacket circulating water outlet is connected to the outlet of the constant temperature water bath through the heating pump and the jacket inlet, and the jacket outlet is connected to the water inlet of the constant temperature water bath;

[0008] Elastic fillers are added inside the biological contact oxidation pond, and the aeration pipe of the aeration pump is connected to the bottom of the elastic filler layer;

[0009] The Fenton oxidizer consists of a first pH adjustment tank, an oxidation tank, and a second pH adjustment tank;

[0010] The water outlet of the anaerobic reactor is connected to the biological contact oxidation tank, and the biological contact oxidation tank is connected to the first pH regulating tank of the Fenton oxidizer.

[0011] The method for treating organophosphorus pesticide wastewater based on "EGSB+biological contact oxidation+Fenton method" of the present invention is as follows:

[0012] 1. Device startup:

[0013] The simulated organophosphorus pesticide wastewater prepared by mixing organophosphorus pesticide and high-concentration organic wastewater is added into the inlet water tank as influent;

[0014] The anaerobic reactor is inoculated with sludge from a high-concentration organic wastewater treatment plant, which contains anaerobic bacteria;

[0015] The biological contact oxidation pond is inoculated with sludge from a sewage treatment plant, which contains heterotrophic bacteria;

[0016] The simulated organophosphorus pesticide wastewater in the water inlet tank is input into the anaerobic reactor through the water inlet pump for treatment, and at the same time, the heating pump is started to input the hot water with a temperature of 34-36° C. in the constant temperature water bath into the jacket 3-3 of the anaerobic reactor for heating circulation; and the reflux pump is started to reflux the wastewater in the anaerobic reactor through the reflux water outlet to the water inlet of the anaerobic reactor with a reflux ratio of 500%-700%; the hydraulic retention time of the wastewater in the anaerobic reactor is controlled to be 22-24 hours;

[0017] The wastewater treated by the anaerobic reactor enters the biological contact oxidation tank through the outlet of the anaerobic reactor for treatment; the water temperature of the biological contact oxidation tank is 20-25°C, the dissolved oxygen is 3-3.5 mg / L, and the hydraulic retention time is 18-24 hours;

[0018] The wastewater treated in the biological contact oxidation tank enters the first pH adjustment tank of the Fenton oxidizer, and enters the oxidation tank after adjusting the pH to 2-4. 2 O 2 、FeSO 3The dosage of H2O2 was 18-22 mL / L and 3.5-4.5 g / L respectively. 2 O 2 、FeSO 3 The Fenton reaction is carried out for 90 to 120 minutes. After the Fenton reaction is completed, the water enters the second pH adjustment tank, the pH is adjusted to 6 to 8, and then the water is discharged;

[0019] After 180 to 200 days of treatment, the startup is completed;

[0020] 2. Stable operation:

[0021] The simulated organophosphorus pesticide wastewater is replaced with the organophosphorus pesticide wastewater to be treated as influent water and added into the influent water tank, and then input into the anaerobic reactor for treatment through the influent pump, and at the same time, the heating pump is started to input the hot water with a temperature of 34-36°C in the constant temperature water bath into the jacket of the anaerobic reactor for heating circulation; and the reflux pump is started to reflux the wastewater in the anaerobic reactor through the reflux water outlet to the water inlet of the anaerobic reactor with a reflux ratio of 500%-700%; the hydraulic retention time of the wastewater in the anaerobic reactor is controlled to be 16-18h;

[0022] The wastewater treated by the anaerobic reactor enters the biological contact oxidation pond through the outlet of the anaerobic reactor; the water temperature of the biological contact oxidation pond is 20-25°C, the dissolved oxygen is 2-3 mg / L, and the hydraulic retention time is 18-24h;

[0023] The wastewater treated in the biological contact oxidation tank enters the first pH adjustment tank of the Fenton oxidizer, and enters the oxidation tank after adjusting the pH to 2-4. 2 O 2 、FeSO 3 The dosage of H2O2 was 18-22 mL / L and 3.5-4.5 g / L respectively. 2 O 2 、FeSO 3 The Fenton reaction is carried out for 90 to 120 minutes. After the Fenton reaction is completed, the wastewater enters the second pH adjustment tank, where the pH is adjusted to 6 to 8, and is discharged to complete the treatment of the organophosphorus pesticide wastewater.

[0024] The present invention adopts EGSB+biological contact oxidation+Fenton method to treat organophosphorus pesticide wastewater, adopts medium-temperature digestion at 34-36°C in the EGSB reactor, controls the height-diameter ratio, and adds a reflux system to dilute the incoming water and make the sludge in a suspended state without loss, which can effectively improve the removal effect of COD and organophosphorus, and converts the difficult-to-degrade organic matter and organophosphorus in the organophosphorus pesticide wastewater into easily degradable organic matter and phosphate in the EGSB reactor.

[0025] Elastic fillers are added to the biological contact oxidation tank to promote the attachment and growth of microorganisms that degrade refractory organic matter with a long generation cycle and convert organic phosphorus into inorganic phosphorus, further degrading organic matter and converting organic phosphorus into phosphate. At the same time, the sludge produced in the biological contact oxidation section is decomposed in this section, and no sludge is discharged in the biological contact oxidation section.

[0026] The Fenton process can further reduce COD, while converting the remaining organic phosphorus into phosphates, and ferrous sulfate into ferric sulfate, which then reacts with phosphate to form ferric phosphate precipitation and is removed, removing both phosphorus and iron ions in the water. Ferric phosphate also acts as a flocculation to remove suspended solids produced in the biological contact oxidation stage.

[0027] Compared with the existing organophosphorus pesticide wastewater treatment method, the present invention has the following advantages:

[0028] 1) Good treatment effect: After the present invention uses EGSB+biological contact oxidation+Fenton method to treat organophosphorus pesticide wastewater, the concentrations of COD, total phosphorus, organophosphorus and phosphate in the effluent are reduced to below 10 mg / L, 1 mg / L, 0.1 mg / L and 1 mg / L respectively, and the removal rates exceed 99.7%, 97.6%, 99.5% and 94.1% respectively. The efficient and stable removal of organophosphorus pesticide wastewater is achieved.

[0029] 2) Low operating cost: The present invention adopts EGSB+biological contact oxidation+Fenton method to treat organophosphorus pesticide wastewater, wherein EGSB and biological contact oxidation method are both biological methods with very low operating costs; Fenton method is used to treat the effluent of biological contact oxidation method, and the concentration of organophosphorus and COD in the effluent is relatively low, requiring less dosage of medicine. Therefore, compared with membrane separation method, evaporation separation, advanced oxidation and incineration method, the operating cost is significantly reduced.

[0030] 3) Low investment: The present invention adopts EGSB+biological contact oxidation+Fenton method to treat organophosphorus pesticide wastewater. EGSB, biological contact oxidation method and Fenton method are all mature technologies, do not require expensive equipment, and have few auxiliary equipment, so the investment is significantly reduced.

[0031] The present invention effectively solves the difficult problems of great difficulty in treating organophosphorus pesticide wastewater, high operating costs and large equipment investment, and achieves efficient and stable removal of pollutants such as COD, total phosphorus and organophosphorus. The treated wastewater can be recycled, which is conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1It is a schematic diagram of a device for treating organophosphorus pesticide wastewater based on "EGSB+biological contact oxidation+Fenton method" of the present invention; in the figure, 1 is a water inlet tank, 2 is a water inlet pump, 3 is an anaerobic reactor, 4 is a heating pump, 5 is a constant temperature water bath, 6 is a reflux pump, 7 is a biological contact oxidation tank, 7-1 is an elastic filler, 7-2 is an aeration pump, 8 is a Fenton oxidizer, 8-1 is a first pH adjustment tank, 8-2 is an oxidation tank, and 8-3 is a second pH adjustment tank;

[0033] Figure 2 3-1 is a schematic diagram of the structure of the anaerobic reactor 3; wherein 3-1 is a water inlet, 3-2 is a water outlet, 3-3 is a jacket, 3-4 is an inlet, 3-5 is an outlet, and 3-6 is a reflux water outlet;

[0034] Figure 3 This is the COD removal effect diagram of EGSB and biological contact oxidation section over time in the stable stage of experiment 1;

[0035] Figure 4 This is the removal effect diagram of total phosphorus and phosphate over time in the EGSB+biological contact oxidation section at the stable stage in Experiment 1;

[0036] Figure 5 This is the removal effect of organic phosphorus over time in the EGSB+biological contact oxidation section at the stable stage in Experiment 1;

[0037] Figure 6 This is the removal effect diagram of COD, total phosphorus, phosphate and organic phosphorus over time in the Fenton section at the stable stage in Experiment 1; DETAILED DESCRIPTION

[0038] Specific implementation method 1: The device for treating organophosphorus pesticide wastewater based on "EGSB+biological contact oxidation+Fenton method" in this implementation method includes an inlet water tank 1, an inlet pump 2, an anaerobic reactor 3, a heating pump 4, a constant temperature water bath 5, a reflux pump 6, a biological contact oxidation tank 7, and a Fenton oxidizer 8;

[0039] The anaerobic reactor 3 has a water inlet 3-1 at the bottom, a water outlet 3-2 at the top side, a jacket 3-3 at the outer wall of the anaerobic reactor 3, an inlet 3-4 and an outlet 3-5 at the jacket, and a reflux water outlet 3-6 at the middle and upper part of the anaerobic reactor 3;

[0040] The inlet water tank 1 is connected to the water inlet 3-1 of the anaerobic reactor 3 via the inlet pump 2; the reflux water outlet 3-6 is connected to the front end water pipe of the inlet pump 2 via the reflux pump 6; the jacket circulating water outlet 3-4 is connected to the outlet of the constant temperature water bath 5 via the heating pump 4 and the jacket inlet 3-4, and the jacket outlet 3-5 is connected to the water inlet of the constant temperature water bath 5;

[0041] Elastic filler 7-1 is added into the biological contact oxidation pond 7, and the aeration pipe of the aeration pump 7-2 is connected to the bottom of the elastic filler 7-1 layer;

[0042] The Fenton oxidizer 8 is composed of a first pH adjustment tank 8-1, an oxidation tank 8-2, and a second pH adjustment tank 8-3;

[0043] The water outlet 3-2 of the anaerobic reactor 3 is connected to the biological contact oxidation tank 7, and the biological contact oxidation tank 7 is connected to the first pH adjustment tank 8-1 of the Fenton oxidizer 8;

[0044] Specific embodiment 2: This embodiment is different from the specific embodiment 1 in that the height-to-diameter ratio of the anaerobic reactor 3 is (6-8):1; the rest is the same as the specific embodiment 1.

[0045] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that the filling ratio of the elastic filler 6-1 is 60% to 65%; the rest is the same as specific implementation methods one or two.

[0046] The elastic filler of this embodiment is conducive to the growth of microorganisms with a long generation period.

[0047] Specific embodiment 4: Using the device for treating organophosphorus pesticide wastewater based on "EGSB+biological contact oxidation+Fenton method" described in specific embodiment 1, a method for treating organophosphorus pesticide wastewater is carried out according to the following steps:

[0048] 1. Device startup:

[0049] The simulated organophosphorus pesticide wastewater prepared by mixing organophosphorus pesticide and high-concentration organic wastewater is added into the inlet water tank 1 as influent;

[0050] The anaerobic reactor 3 is inoculated with sludge from a high-concentration organic wastewater treatment station, and the sludge contains anaerobic bacteria;

[0051] The biological contact oxidation pond is inoculated with sludge from a sewage treatment plant, which contains heterotrophic bacteria;

[0052] The simulated organophosphorus pesticide wastewater in the water inlet tank 1 is input into the anaerobic reactor 3 through the water inlet pump 2 for treatment, and at the same time, the heating pump 4 is started to input the hot water with a temperature of 34-36° C. in the constant temperature water bath 5 into the jacket 3-3 of the anaerobic reactor 3 for heating circulation; and the reflux pump 6 is started to reflux the wastewater in the anaerobic reactor 3 through the reflux water outlet 3-6 to the water inlet 3-1 of the anaerobic reactor 3 with a reflux ratio of 500%-700%; the hydraulic retention time of the wastewater in the anaerobic reactor 3 is controlled to be 22-24 hours;

[0053] The wastewater treated by the anaerobic reactor 3 enters the biological contact oxidation pond 7 through the outlet 3-2 of the anaerobic reactor 3 for treatment; the water temperature of the biological contact oxidation pond 7 is 20-25°C, the dissolved oxygen is 3-3.5 mg / L, and the hydraulic retention time is 18-24 hours;

[0054] The wastewater treated in the biological contact oxidation tank 7 enters the first pH adjustment tank 8-1 of the Fenton oxidizer 8, and enters the oxidation tank 8-2 after adjusting the pH to 2-4; 2 O 2 、FeSO 3 The dosage of H2O2 was 18-22 mL / L and 3.5-4.5 g / L respectively. 2 O 2 、FeSO 3 The Fenton reaction is carried out for 90 to 120 minutes. After the Fenton reaction is completed, the mixture enters the second pH adjustment tank 8-3, where the pH is adjusted to 6 to 8, and the mixture is discharged.

[0055] After 180 to 200 days of treatment, the startup is completed;

[0056] 2. Stable operation:

[0057] The simulated organophosphorus pesticide wastewater is replaced with the organophosphorus pesticide wastewater to be treated as influent water and added into the inlet water tank 1, and then input into the anaerobic reactor 3 for treatment through the inlet pump 2, and at the same time, the heating pump 4 is started to input the hot water with a temperature of 34-36° C. in the constant temperature water bath 5 into the jacket 3-3 of the anaerobic reactor 3 for heating circulation; and the reflux pump 6 is started to reflux the wastewater in the anaerobic reactor 3 through the reflux water outlet 3-6 at a reflux ratio of 500%-700% to the water inlet 3-1 of the anaerobic reactor 3; the hydraulic retention time of the wastewater in the anaerobic reactor 3 is controlled to be 16-18h;

[0058] The wastewater treated by the anaerobic reactor 3 enters the biological contact oxidation pond 7 through the outlet 3-2 of the anaerobic reactor 3; the water temperature of the biological contact oxidation pond 7 is 20-25°C, the dissolved oxygen is 2-3 mg / L, and the hydraulic retention time is 18-24h;

[0059] The wastewater treated in the biological contact oxidation tank 7 enters the first pH adjustment tank 8-1 of the Fenton oxidizer 8, and enters the oxidation tank 8-2 after adjusting the pH to 2-4; 2 O 2 、FeSO 3 The dosage of H2O2 was 18-22 mL / L and 3.5-4.5 g / L respectively. 2 O 2 、FeSO 3The Fenton reaction is carried out, and the Fenton reaction time is 90 to 120 minutes. After the Fenton reaction is completed, it enters the second pH adjustment tank 8-3, and the pH is adjusted to 6 to 8, and then discharged, completing the treatment of the organophosphorus pesticide wastewater.

[0060] Specific implementation method five: This implementation method is different from specific implementation method four in that: in step one, the concentrations of COD, total phosphorus, organic phosphorus, and phosphate in the simulated organophosphorus pesticide wastewater are 3500-4100 mg / L, 42-46 mg / L, 24-27 mg / L, and 17-20 mg / L, respectively; the rest is the same as specific implementation method four.

[0061] Specific implementation method six: This implementation method is different from specific implementation method four or five in that: in step one, the sludge concentration in the anaerobic reactor 3 is 9-11 g / L; the rest is the same as specific implementation method four or five.

[0062] Specific implementation method seven: This implementation method is different from any one of specific implementation methods four to six in that: in step one, the sludge concentration in the biological contact oxidation tank is 1 to 2 g / L; the rest is the same as any one of specific implementation methods four to six.

[0063] Specific embodiment eight: This embodiment differs from any one of specific embodiments four to seven in that: in step one, the temperature of the wastewater in the anaerobic reactor 3 is 25-36° C.; the rest is the same as any one of specific embodiments four to seven.

[0064] Specific embodiment 9: This embodiment differs from specific embodiments 4 to 8 in that: in step 2, the temperature of the wastewater in the anaerobic reactor 3 is 25 to 36° C.; the rest is the same as specific embodiments 4 to 8.

[0065] The following test is used to verify the beneficial effects of the present invention:

[0066] Experiment 1: The device for treating organophosphorus pesticide wastewater based on "EGSB+biological contact oxidation+Fenton method" in this experiment consists of an inlet water tank 1, an inlet pump 2, an anaerobic reactor 3, a heating pump 4, a constant temperature water bath 5, a reflux pump 6, a biological contact oxidation tank 7 and a Fenton oxidizer 8;

[0067] The anaerobic reactor 3 has a water inlet 3-1 at the bottom, a water outlet 3-2 at the top side, a jacket 3-3 at the outer wall of the anaerobic reactor 3, an inlet 3-4 and an outlet 3-5 at the jacket, and a return water outlet 3-6 at the middle and upper part of the anaerobic reactor 3; the effective height of the anaerobic reactor 3 is 60 cm, and the effective diameter is 10 cm;

[0068] The inlet water tank 1 is connected to the water inlet 3-1 of the anaerobic reactor 3 via the inlet pump 2; the reflux water outlet 3-6 is connected to the front end water pipe of the inlet pump 2 via the reflux pump 6; the jacket circulating water outlet 3-4 is connected to the outlet of the constant temperature water bath 5 via the heating pump 4 and the jacket inlet 3-4, and the jacket outlet 3-5 is connected to the water inlet of the constant temperature water bath 5;

[0069] The elastic filler 7-1 with a specification of Φ150 is added inside the biological contact oxidation pond 7, the filling ratio of the elastic filler 7-1 is 65%, and the aeration pipe of the aeration pump 7-2 is connected to the bottom of the elastic filler 7-1 layer;

[0070] The Fenton oxidizer 8 is composed of a first pH adjustment tank 8-1, an oxidation tank 8-2, and a second pH adjustment tank 8-3;

[0071] The water outlet 3-2 of the anaerobic reactor 3 is connected to the biological contact oxidation tank 7, and the biological contact oxidation tank 7 is connected to the first pH adjustment tank 8-1 of the Fenton oxidizer 8;

[0072] The method for treating organophosphorus pesticide wastewater using the device of Experiment 1 is carried out according to the following steps:

[0073] 1. Device startup:

[0074] The simulated organophosphorus pesticide wastewater prepared by mixing organophosphorus pesticide and high-concentration organic wastewater is added into the inlet water tank 1 as influent; wherein the concentrations of COD, total phosphorus, organophosphorus and phosphate of the simulated organophosphorus pesticide wastewater are 3500-4100 mg / L, 42-46 mg / L, 24-27 mg / L and 17-20 mg / L respectively;

[0075] The anaerobic reactor 3 is inoculated with sludge from a high-concentration organic wastewater treatment station, and the sludge contains anaerobic bacteria; the sludge concentration in the anaerobic reactor 3 is 10 g / L;

[0076] The biological contact oxidation pond is inoculated with sludge from a sewage treatment plant containing anaerobic bacteria; the sludge concentration is 1.5 g / L;

[0077] The simulated organophosphorus pesticide wastewater in the water inlet tank 1 is input into the anaerobic reactor 3 through the water inlet pump 2, and at the same time, the heating pump 4 is started to input the hot water with a temperature of 34-36° C. in the constant temperature water bath 5 into the jacket 3-3 of the anaerobic reactor 3 for heating circulation; the reflux pump 6 is started to reflux the wastewater in the anaerobic reactor 3 through the reflux water outlet 3-6 to the water inlet 3-1 of the anaerobic reactor 3 with a reflux ratio of 600%; the hydraulic retention time of the wastewater in the anaerobic reactor 3 is controlled to be 24 hours;

[0078] The wastewater treated by the anaerobic reactor 3 enters the biological contact oxidation pond 7 through the outlet 3-2 of the anaerobic reactor 3 for treatment; the water temperature of the biological contact oxidation pond 7 is 22-24°C, the dissolved oxygen is 3mg / L, and the hydraulic retention time is 20h;

[0079] The wastewater treated in the biological contact oxidation tank 7 enters the first pH adjustment tank 8-1 of the Fenton oxidizer 8, and enters the oxidation tank 8-2 after adjusting the pH to 2-4; 2 O 2 、FeSO 3 The dosage of H2O2 was 20 mL / L and 4 g / L respectively. 2 O 2 、FeSO 3 The Fenton reaction is carried out for 120 minutes. After the Fenton reaction is completed, the mixture enters the second pH adjustment tank 8-3, the pH is adjusted to 7, and the mixture is discharged.

[0080] After 190 days of processing, the startup is completed;

[0081] 2. Stable operation:

[0082] The simulated organophosphorus pesticide wastewater is replaced with the organophosphorus pesticide wastewater to be treated as influent water and added into the influent water tank 1, and then input into the anaerobic reactor 3 through the influent pump 2, and at the same time, the heating pump 4 is started to input the hot water with a temperature of 34-36° C. in the constant temperature water bath 5 into the jacket 3-3 of the anaerobic reactor 3 for heating circulation; the reflux pump 6 is started to reflux the wastewater in the anaerobic reactor 3 through the reflux water outlet 3-6 to the water inlet 3-1 of the anaerobic reactor 3 with a reflux ratio of 600%; the hydraulic retention time of the wastewater in the anaerobic reactor 3 is controlled to be 17 hours;

[0083] The wastewater treated by the anaerobic reactor 3 enters the biological contact oxidation pond 7 through the outlet 3-2 of the anaerobic reactor 3; the water temperature of the biological contact oxidation pond 7 is 22-24°C, the dissolved oxygen is 2.5mg / L, and the hydraulic retention time is 18h;

[0084] The wastewater treated in the biological contact oxidation tank 6 enters the first pH adjustment tank 8-1 of the Fenton oxidizer 8, and enters the oxidation tank 8-2 after adjusting the pH to 3; 2 O 2 、FeSO 3 The dosage of H2O2 was 20 mL / L and 3.5 g / L respectively. 2 O 2 、FeSO 3The Fenton reaction is carried out for 100 minutes. After the Fenton reaction is completed, the wastewater enters the second pH adjustment tank 8-3, where the pH is adjusted to 7, and is discharged, thereby completing the treatment of the organophosphorus pesticide wastewater.

[0085] The method of this experiment is to inoculate anaerobic sludge at a concentration of 10g / L and anaerobic sludge at a concentration of 1.5g / L. After the start-up stage of cultivation, the particle size of the sludge grows to 0.5-1 cm. In the stable stage, under the conditions of a height-to-diameter ratio of 6:1 and a reflux ratio of 600% in the anaerobic reactor, the sludge within this particle size range is suspended in the wastewater and does not retain, thereby increasing the conversion rate of organic phosphorus to inorganic phosphorus. Under the conditions of a filling ratio of 65%, a water temperature of 22-24°C, a dissolved oxygen of 2.5mg / L, and a hydraulic retention time of 18h in the biological contact oxidation tank, the microorganisms in the biological contact oxidation tank convert organic phosphorus into inorganic phosphorus, and at the same time, the dead bacteria in the wastewater are decomposed, and no sludge is discharged during the biological contact oxidation stage. Under the action of Fenton reagent, the wastewater in Fenton oxidizer 8 is oxidized from organic phosphorus to inorganic phosphorus, and ferrous sulfate is converted into ferric sulfate. The ferric sulfate then reacts with phosphate to form iron phosphate precipitation and is removed, and both phosphorus and iron ions in the water are removed. Iron phosphate also acts as a flocculation to remove suspended solids produced during the biological contact oxidation stage.

[0086] The removal effects of COD, total phosphorus, phosphate and organic phosphorus in the stable operation stage are as follows: Figure 3 , 4 , 5 and 6 as shown.

[0087] from Figure 3 It can be seen that in the stable operation stage, the COD of the influent is 3500-4100 mg / L, the COD after treatment in the anaerobic reactor 3 is reduced to 750-1500 mg / L, and the COD after treatment in the biological contact oxidation tank 7 is reduced to 100-250 mg / L.

[0088] from Figure 4 It can be seen that in the stable operation stage, the total phosphorus of the influent is 42-46 mg / L, and the phosphate is 24-27 mg / L; after treatment by the anaerobic reactor 3, the total phosphorus drops to 41-44 mg / L, and the phosphate increases to 32-35 mg / L; after treatment by the biological contact oxidation pond 7, the total phosphorus drops to 38-42 mg / L, and the phosphate drops to 35-39 mg / L.

[0089] from Figure 5 It can be seen that in the stable operation stage, the organic phosphorus in the influent is 24-27 mg / L; after being treated by the anaerobic reactor 3, the organic phosphorus is reduced to 7.5-10 mg / L; and after being treated by the biological contact oxidation tank 7, the organic phosphorus is reduced to 2.5-4 mg / L.

[0090] from Figure 6 It can be seen that in the stable operation stage, after being treated by Fenton oxidizer 8, the COD of the effluent is reduced to 6-8 mg / L, the total phosphorus is reduced to 0.8-1.0 mg / L, the phosphate is reduced to 0.75-0.95 mg / L, and the organic phosphorus is reduced to 0-0.15 mg / L.

Claims

1. A method for treating organophosphorus pesticide wastewater, characterized in that: The method proceeds as follows:

1. Device startup: The device for treating wastewater containing organophosphorus pesticides comprises an inlet water tank (1), an inlet water pump (2), an anaerobic reactor (3), a heating pump (4), a constant temperature water bath (5), a reflux pump (6), a biological contact oxidation tank (7), and a Fenton oxidizer (8); The anaerobic reactor (3) is provided with a water inlet (3-1) at the bottom, a water outlet (3-2) at the top side, a jacket (3-3) at the outer wall of the anaerobic reactor (3), an inlet (3-4) and an outlet (3-5) at the jacket, and a return water outlet (3-6) at the middle and upper part of the anaerobic reactor (3); the height-to-diameter ratio of the anaerobic reactor (3) is (6-8):1; The water inlet tank (1) is connected to the water inlet (3-1) of the anaerobic reactor (3) via the water inlet pump (2); the reflux water outlet (3-6) is connected to the front end water pipe of the water inlet pump (2) via the reflux pump (6); the jacket circulating water outlet 3-4 is connected to the water outlet of the constant temperature water bath (5) via the heating pump (4) and the jacket inlet (3-4), and the jacket outlet (3-5) is connected to the water inlet of the constant temperature water bath (5); An elastic filler (7-1) is added to the interior of the biological contact oxidation pond (7), and an aeration pipe of an aeration pump (7-2) is connected to the bottom of the elastic filler (7-1) layer; the filling ratio of the elastic filler (7-1) in the biological contact oxidation pond (7) is 60% to 65%; The Fenton oxidizer (8) is composed of a first pH adjustment tank (8-1), an oxidation tank (8-2) and a second pH adjustment tank (8-3); The water outlet (3-2) of the anaerobic reactor (3) is connected to the biological contact oxidation tank (7), and the biological contact oxidation tank (7) is connected to the first pH adjustment tank (8-1) of the Fenton oxidizer (8); The simulated organophosphorus pesticide wastewater prepared by mixing organophosphorus pesticide with high-concentration organic wastewater is added into the inlet water tank (1) as influent; wherein the concentrations of COD, total phosphorus, organophosphorus and phosphate in the simulated organophosphorus pesticide wastewater are 3500-4100 mg / L, 42-46 mg / L, 24-27 mg / L and 17-20 mg / L respectively; The anaerobic reactor (3) is inoculated with sludge from a high-concentration organic wastewater treatment station, wherein the sludge contains anaerobic bacteria; the sludge concentration in the anaerobic reactor (3) is 9 to 11 g / L; The biological contact oxidation pond is inoculated with sludge from a sewage treatment plant, which contains anaerobic bacteria; the sludge concentration in the biological contact oxidation pond is 1-2 g / L; The simulated organophosphorus pesticide wastewater in the water inlet tank (1) is input into the anaerobic reactor (3) through the water inlet pump (2) for treatment, and at the same time, the heating pump (4) is started to input hot water with a temperature of 34 to 36° C. in the constant temperature water bath (5) into the jacket (3-3) of the anaerobic reactor (3) for heating circulation; and the reflux pump (6) is started to reflux the wastewater in the anaerobic reactor (3) through the reflux water outlet (3-6) to the water inlet (3-1) of the anaerobic reactor (3) at a reflux ratio of 500% to 700%; and the hydraulic retention time of the wastewater in the anaerobic reactor (3) is controlled to be 22 to 24 hours; The wastewater treated by the anaerobic reactor (3) enters the biological contact oxidation pond (7) through the outlet (3-2) of the anaerobic reactor (3) for treatment; the water temperature of the biological contact oxidation pond (7) is 20-25° C., the dissolved oxygen is 3-3.5 mg / L, and the hydraulic retention time is 18-24 hours; The wastewater treated in the biological contact oxidation tank (7) enters the first pH adjustment tank (8-1) of the Fenton oxidizer (8), and enters the oxidation tank (8-2) after adjusting the pH to 2-4; H2O2 and FeSO3 are added to the oxidation tank (8-2) at a dosage of 18-22 mL / L and 3.5-4.5 g / L, respectively, to carry out a Fenton reaction, and the Fenton reaction time is 90-120 minutes. After the Fenton reaction is completed, the wastewater enters the second pH adjustment tank (8-3), and the pH is adjusted to 6-8, and then discharged; After 180 to 200 days of treatment, the startup is completed; 2. Stable operation: The simulated organophosphorus pesticide wastewater is replaced with the organophosphorus pesticide wastewater to be treated as influent water and added into the influent water tank (1), and then input into the anaerobic reactor (3) for treatment through the influent pump (2), and at the same time, the heating pump (4) is started to input the hot water with a temperature of 34 to 36° C. in the constant temperature water bath (5) into the jacket (3-3) of the anaerobic reactor (3) for heating circulation; and the reflux pump (6) is started to reflux the wastewater in the anaerobic reactor (3) through the reflux water outlet (3-6) to the water inlet (3-1) of the anaerobic reactor (3) at a reflux ratio of 500% to 700%; the hydraulic retention time of the wastewater in the anaerobic reactor (3) is controlled to be 16 to 18 hours; The wastewater treated by the anaerobic reactor (3) enters the biological contact oxidation pond (7) through the outlet (3-2) of the anaerobic reactor (3); the water temperature of the biological contact oxidation pond (7) is 20-25°C, the dissolved oxygen is 2-3 mg / L, and the hydraulic retention time is 18-24 hours; The wastewater treated in the biological contact oxidation tank (7) enters the first pH adjustment tank (8-1) of the Fenton oxidizer (8), and enters the oxidation tank (8-2) after adjusting the pH to 2-4; H2O2 and FeSO3 are added to the oxidation tank (8-2) at dosages of 18-22 mL / L and 3.5-4.5 g / L, respectively, to carry out Fenton reaction, and the Fenton reaction time is 90-120 minutes. After the Fenton reaction is completed, the wastewater enters the second pH adjustment tank (8-3), and the pH is adjusted to 6-8, and then discharged, thereby completing the treatment of the organophosphorus pesticide wastewater.

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