Treatment method of phosphorus-containing industrial wastewater

Abstract

The invention discloses a method for treating phosphorus-containing industrial wastewater. The method comprises the following steps: adding a Fenton reagent into wastewater to enable the pH value to be 4-6, stirring, adding calcium hydroxide and aluminum sulfate into effluent to enable the pH value to be 8-10, stirring, adding polyacrylamide, precipitating the effluent, performing adsorption treatment by using a composite adsorbent, separating, and discharging the effluent, the preparation process of the composite adsorbent comprises the following steps: adding fly ash and volcanic rock into water with the pH value of 8-9, soaking at 45-55 DEG C for 4-8 days, roasting at 150-270 DEG C for 3-5 hours, cooling to room temperature, mixing with ferrous chloride, calcium chloride and diethylene triamine pentaacetic acid, adding water, stirring at room temperature for 3-5 hours, drying and crushing to obtain a material A; uniformly mixing sludge, activated carbon, peanut shells and oyster shells, adding a nitric acid solution, stirring the mixture into mud, and heating the mud at 650-750 DEG C for 150-240 minutes to obtain a material B; and uniformly mixing the material A, the material B, diatomite and natural zeolite.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly to a method for treating phosphorus-containing industrial wastewater. Background Art

[0002] The discharge of a large amount of industrial wastewater containing phosphorus elements causes the rapid reproduction of plankton in water bodies, the decrease of dissolved oxygen in water bodies, and seriously pollutes the water environment, bringing great harm to industries, agriculture, tourism, etc. Therefore, phosphorus-containing industrial wastewater must be treated before discharge, and the development of good technologies for removing and recovering phosphorus-containing wastewater is of great significance for sustainable development. At present, the treatment of phosphorus-containing wastewater mainly includes biological methods, chemical methods, adsorption methods, etc. Although a variety of treatment processes have been disclosed in the prior art, there are still defects in the poor phosphorus removal rate, which limits their application. Summary of the Invention

[0003] Based on the technical problems existing in the background art, the present invention proposes a method for treating phosphorus-containing industrial wastewater, which has a simple and easy process and a high phosphorus removal rate.

[0004] A method for treating phosphorus-containing industrial wastewater proposed by the present invention includes the following steps:

[0005] S1. Add Fenton's reagent to the phosphorus-containing industrial wastewater and adjust the pH value to 4-6, and stir for reaction;

[0006] S2. Add calcium hydroxide and aluminum sulfate to the effluent obtained after the reaction in S1 and adjust the pH value to 8-10, stir, add the coagulant aid polyacrylamide, and the effluent is obtained as the primary treated water after precipitation;

[0007] S3. Adsorb and treat the primary treated water with a composite adsorbent, separate, and discharge the effluent;

[0008] Wherein, the preparation process of the composite adsorbent includes the following steps: Add fly ash and volcanic rock to water with a pH of 8-9, soak at 45-55°C for 4-8 days, separate and calcine at 150-270°C for 3-5 h, cool to room temperature and mix with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid, add water and stir at room temperature for 3-5 h, dry and crush to obtain material A; Crush sludge activated carbon, peanut shells, and oyster shells and mix them evenly, add nitric acid solution and stir into a mud shape, heat at 650-750°C for 150-240 min to obtain material B; Mix material A, material B, diatomite, and natural zeolite evenly to obtain the composite adsorbent.

[0009] Preferably, in S1, the stirring time is 90-130 min.

[0010] Preferably, in S2, the stirring time is 20-35 min.

[0011] Preferably, in S2, the weight of the polyacrylamide is 0.2-0.8% of the weight of the wastewater to be treated.

[0012] Preferably, in S3, the dosage of the composite adsorbent is 0.5-2.8 g / L; the temperature of the adsorption treatment is 25-35°C, and the time is 3-4.5 h.

[0013] Preferably, in the preparation process of the composite adsorbent in S3, the weight ratio of fly ash, volcanic rock, ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid is 100-200:50-100:7-10:6-15:20-30.

[0014] Preferably, in the preparation process of the composite adsorbent in S3, the weight ratio of sludge activated carbon, peanut shell, and oyster shell is 30-45:9-15:10-22.

[0015] Preferably, in the preparation process of the composite adsorbent in S3, the weight ratio of material A, material B, diatomite, and natural zeolite is 3-9:2-7:1-3:1-5.

[0016] Preferably, in the preparation process of the composite adsorbent in S3, the natural zeolite is natural zeolite modified with cetyltrimethylammonium bromide.

[0017] In the method for treating the phosphorus-containing industrial wastewater of the present invention, first, a Fenton reagent is added to the phosphorus-containing industrial wastewater to make the pH value 4-6, converting the phosphate in the form of non-orthophosphate in the wastewater into orthophosphate. After coagulation and precipitation, a specific composite adsorbent is used for treatment, resulting in a high phosphorus removal rate of the wastewater and reducing the phosphorus content in the wastewater to below 0.13 mg / L; in the preparation process of the composite adsorbent, first, fly ash and volcanic rock are soaked in water with a pH of 8-9, activating their surfaces using their alkaline environment to form active sites for adsorbing phosphate ions. After roasting, they are mixed with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid, introducing surface functional carboxyl groups as well as iron and calcium, with good stability and strong ability to bind phosphate ions. Then, they are mixed with the product obtained by mixing and calcining diatomite, natural zeolite, sludge activated carbon, and peanut shell and oyster shell as the composite adsorbent, which has a large specific surface area and good activity, is used for the treatment of phosphorus-containing wastewater, has strong adsorption ability, and a high phosphorus removal rate.

[0018] In the treatment method of the present invention, a variety of methods such as Fenton reagent oxidation, coagulation and precipitation, and adsorbent adsorption are combined simultaneously to play a synergistic role, reducing the concentration of phosphorus in the treated effluent to below 0.13 mg / L, meeting the first-class standard specified in the comprehensive discharge standard GB8978-96, and having a simple process flow. Detailed implementation mode

[0019] Next, the technical solution of the present invention will be described in detail through specific embodiments.

[0020] Example 1

[0021] A method for treating phosphorus-containing industrial wastewater includes the following steps:

[0022] S1. Add Fenton's reagent to the phosphorus-containing industrial wastewater and adjust the pH value to 6, then stir for reaction.

[0023] S2. Add calcium hydroxide and aluminum sulfate to the effluent obtained after the reaction in S1 and adjust the pH value to 8, then stir, add the coagulant aid polyacrylamide, and the effluent is obtained as the primary treated water after precipitation.

[0024] S3. Adsorb the primary treated water with a composite adsorbent, separate, and discharge the effluent.

[0025] Among them, the preparation process of the composite adsorbent includes the following steps: Add fly ash and volcanic rock to water with a pH of 9, soak at 45 °C for 8 days, separate and then calcine at 150 °C for 5 h, cool to room temperature and mix with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid, add water and stir at room temperature for 3 h, dry and crush to obtain material A; Crush and mix sludge activated carbon, peanut shells, and oyster shells evenly, add nitric acid solution and stir into a mud shape, heat at 750 °C for 200 min to obtain material B; Mix material A, material B, diatomite, and natural zeolite evenly to obtain the composite adsorbent.

[0026] Example 2

[0027] A method for treating phosphorus-containing industrial wastewater includes the following steps:

[0028] S1. Add Fenton's reagent to the phosphorus-containing industrial wastewater and adjust the pH value to 4, then stir for reaction for 90 min.

[0029] S2. Add calcium hydroxide and aluminum sulfate to the effluent obtained after the reaction in S1 and adjust the pH value to 10, then stir for 35 min, add the coagulant aid polyacrylamide, and the weight of the polyacrylamide is 0.2% of the weight of the wastewater to be treated; the effluent is obtained as the primary treated water after precipitation.

[0030] S3. Adsorb the primary treated water with a composite adsorbent for 4.5 h, separate, and discharge the effluent.

[0031] Among them, the addition amount of the composite adsorbent is 2.8 g / L; the temperature of the adsorption treatment is 25 °C; the preparation process of the composite adsorbent includes the following steps: adding fly ash and volcanic rock into water with a pH of 8, soaking at 55 °C for 4 days, separating and then roasting at 270 °C for 3 h, cooling to room temperature and then mixing with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid, adding water and stirring at room temperature for 5 h, drying and pulverizing to obtain material A; pulverizing sludge activated carbon, peanut shells, and oyster shells and mixing them evenly, adding nitric acid solution and stirring into a mud shape, heating at 650 °C for 240 min to obtain material B; mixing material A, material B, diatomite, and natural zeolite evenly to obtain the composite adsorbent; among them, the weight ratio of fly ash, volcanic rock, ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid is 100:100:8:11:20; the weight ratio of sludge activated carbon, peanut shells, and oyster shells is 30:15:15; the weight ratio of material A, material B, diatomite, and natural zeolite is 5:2:3:1; the natural zeolite is natural zeolite modified by cetyltrimethylammonium bromide.

[0032] Example 3

[0033] A method for treating phosphorus-containing industrial wastewater includes the following steps:

[0034] S1. Adding Fenton reagent to the phosphorus-containing industrial wastewater and adjusting the pH value to 5, stirring for reaction;

[0035] S2. Adding calcium hydroxide and aluminum sulfate to the effluent obtained after the reaction in S1 and adjusting the pH value to 8, stirring, adding the coagulant aid polyacrylamide, and the effluent is subjected to precipitation to obtain the primary treated water;

[0036] S3. Adsorbing and treating the primary treated water with the composite adsorbent, separating, and discharging the effluent;

[0037] Among them, the preparation process of the composite adsorbent includes the following steps: adding fly ash and volcanic rock into water with a pH of 8, soaking at 52 °C for 5 days, separating and then roasting at 220 °C for 3.8 h, cooling to room temperature and then mixing with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid, adding water and stirring at room temperature for 3 h, drying and pulverizing to obtain material A; pulverizing sludge activated carbon, peanut shells, and oyster shells and mixing them evenly, adding nitric acid solution and stirring into a mud shape, heating at 720 °C for 150 min to obtain material B; mixing material A, material B, diatomite, and natural zeolite evenly to obtain the composite adsorbent;

[0038] Among them, in S1, the stirring time is 130 min;

[0039] In S2, the stirring time is 20 min; the weight of the polyacrylamide is 0.8% of the weight of the wastewater to be treated;

[0040] In S3, the dosage of the composite adsorbent is 0.5 g / L; the temperature of the adsorption treatment is 35 °C, and the time is 3 h; in the preparation process of the composite adsorbent, the weight ratio of fly ash, volcanic rock, ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid is 200:50:10:15:30; the weight ratio of sludge activated carbon, peanut shell, and oyster shell is 45:9:22; the weight ratio of material A, material B, diatomite, and natural zeolite is 9:7:1:5; the natural zeolite is natural zeolite modified by cetyltrimethylammonium bromide.

[0041] Example 4

[0042] A method for treating phosphorus-containing industrial wastewater, comprising the following steps:

[0043] S1. Add Fenton reagent to the phosphorus-containing industrial wastewater and adjust the pH value to 5, and stir for reaction for 100 min;

[0044] S2. Add calcium hydroxide and aluminum sulfate to the effluent obtained after the reaction in S1 and adjust the pH value to 8, stir for 30 min, add the coagulant aid polyacrylamide, and the effluent is obtained as the primary treated water after precipitation; wherein, the weight of the polyacrylamide is 0.5% of the weight of the wastewater to be treated;

[0045] S3. Adsorb and treat the primary treated water with a composite adsorbent for 3.9 h, separate, and discharge the effluent;

[0046] Wherein, the temperature of the adsorption treatment is 32 °C; the dosage of the composite adsorbent is 1 g / L; the preparation process of the composite adsorbent comprises the following steps: Add fly ash and volcanic rock to water with a pH of 8, soak at 48 °C for 5 days, separate and calcine at 260 °C for 3.5 h, cool to room temperature and mix with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid, add water and stir at room temperature for 4.5 h, dry and crush to obtain material A; Crush sludge activated carbon, peanut shell, and oyster shell and mix them evenly, add nitric acid solution and stir into a paste, and heat at 680 °C for 220 min to obtain material B; Mix material A, material B, diatomite, and natural zeolite evenly to obtain the composite adsorbent; wherein, in the preparation process of the composite adsorbent, the weight ratio of fly ash, volcanic rock, ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid is 120:90:7:6:23; the weight ratio of sludge activated carbon, peanut shell, and oyster shell is 39:13:10; the weight ratio of material A, material B, diatomite, and natural zeolite is 3:6:2:4; the natural zeolite is natural zeolite modified by cetyltrimethylammonium bromide.

[0047] Example 5

[0048] A method for treating industrial wastewater containing phosphorus, comprising the following steps:

[0049] S1. Add Fenton reagent to the industrial wastewater containing phosphorus and adjust the pH value to 4, then stir for reaction;

[0050] S2. Add calcium hydroxide and aluminum sulfate to the effluent obtained after the reaction in S1 and adjust the pH value to 10, stir, add the coagulant aid polyacrylamide, and the effluent is obtained as the primary treated water after precipitation;

[0051] S3. Adsorb and treat the primary treated water with a composite adsorbent, separate, and discharge the effluent;

[0052] Among them, the preparation process of the composite adsorbent includes the following steps: Add fly ash and volcanic rock to water with a pH of 9, soak at 45 °C for 7 days, separate and then calcine at 158 °C for 4 h, cool to room temperature and mix with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid, add water and stir at room temperature for 3 h, dry and crush to obtain material A; Crush and mix sludge activated carbon, peanut shells, and oyster shells evenly, add nitric acid solution and stir into a paste, and heat at 700 °C for 180 min to obtain material B; Mix material A, material B, diatomite, and natural zeolite evenly to obtain the composite adsorbent;

[0053] Among them, in S1, the stirring time is 120 min;

[0054] In S2, the stirring time is 25 min; the weight of the polyacrylamide is 0.7% of the weight of the wastewater to be treated;

[0055] In S3, the dosage of the composite adsorbent is 2 g / L; the temperature of the adsorption treatment is 29 °C and the time is 4.2 h; in the preparation process of the composite adsorbent, the weight ratio of fly ash, volcanic rock, ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid is 180:75:8:11:27; the weight ratio of sludge activated carbon, peanut shells, and oyster shells is 41:10:19; the weight ratio of material A, material B, diatomite, and natural zeolite is 8:4:1:3; the natural zeolite is natural zeolite modified with cetyltrimethylammonium bromide.

[0056] Example 6

[0057] A method for treating industrial wastewater containing phosphorus, comprising the following steps:

[0058] S1. Add Fenton reagent to the industrial wastewater containing phosphorus and adjust the pH value to 5, stir for reaction for 120 min;

[0059] S2. Add calcium hydroxide and aluminum sulfate to the effluent obtained after the reaction in S1 and adjust the pH value to 9. Stir for 30 min, then add the coagulant aid polyacrylamide. The effluent is obtained as the primary treated water after sedimentation. Among them, the weight of the polyacrylamide is 0.55% of the weight of the wastewater to be treated.

[0060] S3. Adsorb the primary treated water with a composite adsorbent for 3.7 h, separate it, and discharge the effluent.

[0061] Among them, the dosage of the composite adsorbent is 1.3 g / L; the temperature of the adsorption treatment is 28 °C; the preparation process of the composite adsorbent includes the following steps: Add fly ash and volcanic rock to water with a pH of 8, soak at 50 °C for 6 days, separate, and then calcine at 210 °C for 3.8 h. After cooling to room temperature, mix with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid. Add water and stir at room temperature for 4 h, then dry and crush to obtain material A. Among them, the weight ratio of fly ash, volcanic rock, ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid is 160:73:8:12:27; Crush sludge activated carbon, peanut shells, and oyster shells and mix them evenly. Add nitric acid solution and stir into a paste, then heat at 690 °C for 185 min to obtain material B. Among them, the weight ratio of sludge activated carbon, peanut shells, and oyster shells is 39:12:17; Mix material A, material B, diatomite, and natural zeolite evenly to obtain the composite adsorbent. Among them, the weight ratio of material A, material B, diatomite, and natural zeolite is 7:5:2:4; The natural zeolite is natural zeolite modified with cetyltrimethylammonium bromide.

[0062] Comparative Example 1

[0063] It is only different from Example 6 in that: in S2, calcium hydroxide is not added. Add aluminum sulfate to the effluent obtained after the reaction in S1 and adjust the pH value to 9.

[0064] Comparative Example 2

[0065] It is only different from Example 6 in that: during the preparation process of the composite adsorbent, fly ash is not added, but volcanic rock is directly added to water with a pH of 8 for subsequent treatment.

[0066] Comparative Example 3

[0067] It is only different from Example 6 in that: during the preparation process of the composite adsorbent, ferrous chloride is not added, that is, after cooling to room temperature, it is mixed with calcium chloride and diethylenetriaminepentaacetic acid for subsequent reaction.

[0068] Comparative Example 4

[0069] It is only different from Example 6 in that: during the preparation of the composite adsorbent, diethylenetriaminepentaacetic acid was not added, that is, after cooling to room temperature, it was mixed with ferrous chloride and calcium chloride.

[0070] Comparative Example 5

[0071] It is only different from Example 6 in that: during the preparation of the composite adsorbent, calcium chloride was not added, that is, after cooling to room temperature, it was mixed with ferrous chloride and diethylenetriaminepentaacetic acid.

[0072] Comparative Example 6

[0073] It is only different from Example 6 in that: during the preparation of the composite adsorbent, Material B was not added, but the obtained Material A was directly mixed evenly with diatomite and natural zeolite to obtain the composite adsorbent.

[0074] For the phosphorus-containing wastewater in Examples 1-6 and Comparative Examples 1-6, the total phosphorus was 120 mg / L and the pH was 6.8. The treated effluents were respectively detected. Among them, the total phosphorus (calculated as P) in the effluents of Examples 1-6 was all ≤ 0.12 mg / L, while the total phosphorus (calculated as P) in the effluents of Comparative Examples 1-6 was all ≥ 0.49 mg / L.

[0075] As mentioned above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A method for treating industrial wastewater containing phosphorus, characterized in that, it comprises the following steps: S1. Add Fenton reagent to the industrial wastewater containing phosphorus and adjust the pH value to 4 - 6, then stir for reaction; S2. Add calcium hydroxide and aluminum sulfate to the effluent obtained after the reaction in S1 and adjust the pH value to 8 - 10, stir, add the coagulant aid polyacrylamide, and the effluent is obtained as the primary treated water after precipitation; S3. Adsorb and treat the primary treated water with a composite adsorbent, separate, and discharge the effluent; wherein, the preparation process of the composite adsorbent comprises the following steps: Add fly ash and volcanic rock to water with a pH of 8 - 9, soak at 45 - 55 °C for 4 - 8 days, separate and then calcine at 150 - 270 °C for 3 - 5 h, cool to room temperature and mix with ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid, add water and stir at room temperature for 3 - 5 h, dry and crush to obtain material A; Crush and mix sludge activated carbon, peanut shells, and oyster shells evenly, add nitric acid solution and stir into a paste, heat at 650 - 750 °C for 150 - 240 min to obtain material B; Mix material A, material B, diatomite, and natural zeolite evenly to obtain the composite adsorbent.

2. The method for treating industrial wastewater containing phosphorus according to claim 1, characterized in that, in S1, the stirring time is 90 - 130 min.

3. The method for treating industrial wastewater containing phosphorus according to claim 1, characterized in that, in S2, the stirring time is 20 - 35 min.

4. The method for treating industrial wastewater containing phosphorus according to claim 1, characterized in that, in S2, the weight of the polyacrylamide is 0.2 - 0.8% of the weight of the wastewater to be treated.

5. The method for treating industrial wastewater containing phosphorus according to claim 1, characterized in that, in S3, the dosage of the composite adsorbent is 0.5 - 2.8 g / L; the temperature of the adsorption treatment is 25 - 35 °C, and the time is 3 - 4.5 h.

6. The method for treating industrial wastewater containing phosphorus according to claim 1, characterized in that, in the preparation process of the composite adsorbent in S3, the weight ratio of fly ash, volcanic rock, ferrous chloride, calcium chloride, and diethylenetriaminepentaacetic acid is 100 - 200:50 - 100:7 - 10:6 - 15:20 - 30.

7. The method for treating industrial wastewater containing phosphorus according to claim 1, characterized in that, in the preparation process of the composite adsorbent in S3, the weight ratio of sludge activated carbon, peanut shells, and oyster shells is 30 - 45:9 - 15:10 - 22.

8. The method for treating industrial wastewater containing phosphorus according to claim 1, characterized in that, in the preparation process of the composite adsorbent in S3, the weight ratio of material A, material B, diatomite, and natural zeolite is 3 - 9:2 - 7:1 - 3:1 - 5.

9. The method for treating industrial wastewater containing phosphorus according to any one of claims 1 - 8, characterized in that, in the preparation process of the composite adsorbent in S3, the natural zeolite is natural zeolite modified with cetyltrimethylammonium bromide.