An urban sewage denitrification and phosphorus removal treatment process

Abstract

The present invention discloses a treatment process for denitrification and phosphorus removal from urban sewage. In the present invention, three treatment processes, namely a flocculation tank, an aeration tank and a wetland treatment pool, are used to treat sewage. The flocculant can remove harmful impurities such as grease and germs in urban sewage. In the aeration tank of the present invention, reasonable filter fillers are adopted, which can improve the stability of the fillers, increase the adsorption amount of microorganisms in the water body, and further improve the treatment effect of sewage in combination with a reasonable air-water ratio. In the present invention, a reasonable bottom layout and aquatic plants are combined to further remove harmful substances in the water body.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and particularly to a process for removing nitrogen and phosphorus from urban sewage. Background Art

[0002] Urban sewage refers to domestic sewage, industrial wastewater and runoff sewage within the scope of urban areas. In addition to containing a large amount of organic matter, germs and viruses, due to the highly developed industry, the water quality of urban sewage has become increasingly complex, and the pollution of runoff sewage has also become increasingly serious, making urban sewage contain various types and degrees of harmful pollutants. Therefore, a treatment process for removing harmful substances such as nitrogen and phosphorus from urban sewage is needed. Summary of the Invention

[0003] In view of this, the present invention proposes a process for removing nitrogen and phosphorus from urban sewage to solve the above problems.

[0004] The technical solution of the present invention is realized as follows:

[0005] A process for removing nitrogen and phosphorus from urban sewage includes the following steps:

[0006] (1) Filter the sewage through a fence and divert it to a flocculation tank, and add a flocculant to the flocculation tank. The raw materials of the flocculant by weight include 5-7 parts of polyacrylamide, 2-4 parts of dimethyldiallylammonium chloride, 6-8 parts of methylvinylchlorosilane and 0.03-0.05 part of an initiator to obtain primary treated sewage;

[0007] (2) Introduce the primary treated sewage into an aeration tank. The packing materials of the aeration tank include ceramsite, activated carbon and polypropylene to obtain secondary treated sewage;

[0008] (3) Introduce the secondary treated sewage into a wetland treatment pool. Montmorillonite, kaolinite and calcite are laid on the bottom of the wetland treatment pool, and water hyacinths, arrowhead and iris pseudacorus are planted in the wetland treatment pool.

[0009] Further, in step (1), the initiator includes hydrogen peroxide, azobisisobutyronitrile and ferrous sulfate with a mass ratio of 1:3-5:2-3.

[0010] Further, the preparation method of the flocculant is to mix polyacrylamide, dimethyldiallylammonium chloride, methylvinylchlorosilane and water. The mass ratio of polyacrylamide to water is 1:5, add the initiator and stir for 1 hour, heat up to 80 °C, and react for 4 h to prepare the flocculant.

[0011] Further, in step (1), the dosage of the flocculant is 150-200 mg / L.

[0012] Further, in step (1), after adding the flocculant, stir at 150 r / min for 2 min, then stir at 70 r / min for 20 min, and let it stand for 90 min.

[0013] In the present invention, the raw materials of the flocculant by weight include 5 - 7 parts of polyacrylamide, 2 - 4 parts of dimethyldiallylammonium chloride, 6 - 8 parts of methylvinylchlorosilane, and 0.03 - 0.05 parts of initiator, which can remove harmful impurities such as grease and germs in urban sewage.

[0014] Further, in step (2), the air - water ratio in the aeration tank is 5 - 6, and the hydraulic load is 2 - 2.4 m 3 / (m 2 ·d), and the treatment time is 6 - 8 h.

[0015] Further, in step (2), the mass ratio of ceramsite, activated carbon, and polypropylene is 3 - 5:8 - 12:6 - 7.

[0016] Further, the diameters of the ceramsite and activated carbon are 5 - 8 mm and 2 - 4 mm respectively.

[0017] In the aeration tank of the present invention, a reasonable filter packing is adopted, which can improve the stability of the packing, increase the adsorption amount of microorganisms in the water body, and combined with a reasonable air - water ratio, can further improve the sewage treatment effect.

[0018] Further, in step (3), the mass ratio of montmorillonite, kaolinite, and calcite is 4 - 5:1 - 2:3 - 6.

[0019] Further, in step (3), the planting ratio of water hyacinth, sagittaria trifolia, and iris pseudacorus is 1:3 - 5:8 - 10.

[0020] Further, the planting density of water hyacinth, sagittaria trifolia, and iris pseudacorus is 20 - 35 plants / m 3 .

[0021] In the present invention, a reasonable combination of the pond bottom layout and aquatic plants can further remove harmful substances in the water body.

[0022] Further, in step (3), sprinkle the microbial preparation, and the microbial preparation includes actinomycetes mobilis, alcaligenes viscolactis, and bacillus laterosporus with a mass ratio of 1:0.5 - 0.8:2 - 2.4.

[0023] Further, the dosage of the microbial preparation is 15 - 25 g / m 3 .

[0024] In the present invention, a microbial agent is prepared from Actinoplanes sp., Alcaligenes lactolyticus and Bacillus laterosporus, and is sprinkled into a wetland treatment pond, which can prevent the blue-green algae phenomenon caused by excessive harmful substances in sewage and improve the treatment effect of the wetland treatment pond.

[0025] Advantages of the present invention:

[0026] In the present invention, the flocculant is composed of raw materials by weight including 5-7 parts of polyacrylamide, 2-4 parts of dimethyldiallylammonium chloride, 6-8 parts of methylvinylchlorosilane and 0.03-0.05 part of initiator, and can remove harmful impurities such as grease and germs in urban sewage. In the aeration tank of the present invention, reasonable filter fillers are adopted, which can improve the stability of the fillers and increase the adsorption amount of microorganisms in the water body. Combined with a reasonable air-water ratio, the treatment effect of sewage can be further improved. In the present invention, a reasonable bottom layout and aquatic plants are combined to further remove harmful substances in the water body. In the present invention, a microbial agent is prepared from Actinoplanes sp., Alcaligenes lactolyticus and Bacillus laterosporus, and is sprinkled into a wetland treatment pond, which can prevent the blue-green algae phenomenon caused by excessive harmful substances in sewage and improve the treatment effect of the wetland treatment pond. Further, in the present invention, a microbial agent is put into the wetland treatment pond. Due to the reasonable layout of aquatic plants in the wetland treatment pond, the wetland treatment pond has the ability to adjust water temperature and pH value, which is beneficial to improving the effect of the microbial agent in removing harmful substances in water. Detailed implementation mode

[0027] To better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0028] Actinoplanes sp. was purchased from Shanghai Yansheng Industrial Co., Ltd.; Alcaligenes lactolyticus was purchased from Shanghai Beinuo Biotechnology Co., Ltd.; Bacillus laterosporus was purchased from Shandong Ruichen Biotechnology Co., Ltd.

[0029] Example 1

[0030] (1) After the sewage is filtered by a fence and diverted to a flocculation tank, the flocculant is put into the flocculation tank at a dosage of 150 mg / L. The raw materials of the flocculant by weight include 5 parts of polyacrylamide, 2 parts of dimethyldiallylammonium chloride, 6 parts of methylvinylchlorosilane and 0.03 part of initiator. The initiator is composed of hydrogen peroxide, azobisisobutyronitrile and ferrous sulfate with a mass ratio of 1:3:2. The preparation method of the flocculant is to mix polyacrylamide, dimethyldiallylammonium chloride, methylvinylchlorosilane and water. The mass ratio of polyacrylamide to water is 1:5. Add the initiator and stir for 1 hour, heat up to 80 °C, and react for 4 h to obtain the flocculant. After adding the flocculant, stir at 150 r / min for 2 min, then stir at 70 r / min for 20 min, and let stand for 90 min to obtain the primary treated sewage;

[0031] (2) Introduce the primary treated sewage into the aeration tank. The packing materials in the aeration tank include ceramsite, activated carbon and polypropylene. The mass ratio of ceramsite, activated carbon and polypropylene is 3:8:6. The diameters of ceramsite and activated carbon are 5 - 8 mm and 2 - 4 mm respectively. The gas-water ratio in the aeration tank is 5, and the hydraulic load is 2 m 3 / (m 2 ·d), and the treatment time is 6 h to obtain the secondary treated sewage;

[0032] (3) Introduce the secondary treated sewage into the wetland treatment pool and sprinkle the microbial preparation. The microbial preparation is composed of Actinoplanes mobilis, Alcaligenes viscolactis and Bacillus laterosporus with a mass ratio of 1:0.5:2. The dosage of the microbial preparation is 15 g / m 3 . Montmorillonite, kaolinite and calcite are laid on the bottom of the wetland treatment pool. The mass ratio of montmorillonite, kaolinite and calcite is 4:1:3. Eichhornia crassipes, Sagittaria trifolia and Iris pseudacorus are planted in the wetland treatment pool. The planting ratio of Eichhornia crassipes, Sagittaria trifolia and Iris pseudacorus is 1:3:8, and the planting density of Eichhornia crassipes, Sagittaria trifolia and Iris pseudacorus is 24 plants / m 3 .

[0033] Example 2

[0034] (1) After filtering the sewage with a fence, divert it to the flocculation tank. Add the flocculant at a dosage of 200 mg / L in the flocculation tank. The raw materials of the flocculant are composed of 7 parts of polyacrylamide, 4 parts of dimethyldiallylammonium chloride, 8 parts of methylvinylchlorosilane and 0.05 part of initiator by weight. The initiator is composed of hydrogen peroxide, azobisisobutyronitrile and ferrous sulfate with a mass ratio of 1:5:3. The preparation method of the flocculant is to mix polyacrylamide, dimethyldiallylammonium chloride, methylvinylchlorosilane and water. The mass ratio of polyacrylamide and water is 1:5. Add the initiator and stir for 1 hour, then heat up to 80 °C and react for 4 h to prepare the flocculant. After adding the flocculant, stir at 150 r / min for 2 min, then stir at 70 r / min for 20 min, and let it stand for 90 min to obtain the primary treated sewage;

[0035] (2) Introduce the primary treated sewage into the aeration tank. The packing materials in the aeration tank include ceramsite, activated carbon and polypropylene. The mass ratio of ceramsite, activated carbon and polypropylene is 5:12:7. The diameters of ceramsite and activated carbon are 8 mm and 4 mm respectively. The gas-water ratio in the aeration tank is 6, and the hydraulic load is 2.4 m 3 / (m 2 ·d), and the treatment time is 8 h to obtain the secondary treated sewage;

[0036] (3) Introduce the secondary treated sewage into the wetland treatment pool, and sprinkle the microbial preparation. The microbial preparation is composed of Actinoplanes mobilis, Alcaligenes viscolactis, and Bacillus laterosporus with a mass ratio of 1:0.8:2.4. The dosage of the microbial preparation is 25 g / m 3 , lay montmorillonite, kaolinite, and calcite on the bottom of the wetland treatment pool. The mass ratio of montmorillonite, kaolinite, and calcite is 5:2:6. Plant Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus in the wetland treatment pool. The planting ratio of Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus is 1:5:10. The planting density of Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus is 32 plants / m 3 .

[0037] Example 3

[0038] (1) After filtering the sewage with a fence, divert it to the flocculation tank. Add the flocculant at a dosage of 180 mg / L in the flocculation tank. The raw materials of the flocculant are composed of 6 parts of polyacrylamide, 3 parts of dimethyldiallylammonium chloride, 7 parts of methylvinylchlorosilane, and 0.04 part of initiator by weight. The initiator is composed of hydrogen peroxide, azobisisobutyronitrile, and ferrous sulfate with a mass ratio of 1:4:2.5. The preparation method of the flocculant is to mix polyacrylamide, dimethyldiallylammonium chloride, methylvinylchlorosilane, and water. The mass ratio of polyacrylamide to water is 1:5. Add the initiator and stir for 1 hour, then heat up to 80 °C and react for 4 h to obtain the flocculant. After adding the flocculant, stir at 150 r / min for 2 min, then stir at 70 r / min for 20 min, and let it stand for 90 min to obtain the primary treated sewage;

[0039] (2) Introduce the primary treated sewage into the aeration tank. The fillers in the aeration tank include ceramsite, activated carbon, and polypropylene. The mass ratio of ceramsite, activated carbon, and polypropylene is 4:10:6.5. The diameters of ceramsite and activated carbon are 5 - 8 mm and 2 - 4 mm respectively. The gas-water ratio in the aeration tank is 6, and the optimal hydraulic load is 2.2 m 3 / (m 2 ·d), and the treatment time is 8 h to obtain the secondary treated sewage;

[0040] (3) Introduce the secondary treated sewage into the wetland treatment pool, and sprinkle the microbial preparation. The microbial preparation is composed of Actinoplanes mobilis, Alcaligenes viscolactis, and Bacillus laterosporus with a mass ratio of 1:0.7:2.2. The dosage of the microbial preparation is 20 g / m 3 , lay montmorillonite, kaolinite, and calcite on the bottom of the wetland treatment pool. The mass ratio of montmorillonite, kaolinite, and calcite is 4.5:1.5:5. Plant Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus in the wetland treatment pool. The planting ratio of Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus is 1:4:9. The planting density of Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus is 28 plants / m 3 .

[0041] Comparative Example 1

[0042] (1) The sewage is filtered by a fence and then diverted to a flocculation tank, where a microbial preparation is sprinkled. The microbial preparation is composed of Actinoplanes mobilis, Alcaligenes viscolactis, and Bacillus laterosporus with a mass ratio of 1:0.7:2.2. The dosage of the microbial preparation is 20 g / m 3 , and a flocculant is added to the flocculation tank at a dosage of 180 mg / L. The raw materials of the flocculant are composed of 6 parts of polyacrylamide, 3 parts of dimethyldiallylammonium chloride, 7 parts of methylvinylchlorosilane, and 0.04 part of an initiator by weight. The initiator is composed of hydrogen peroxide, azobisisobutyronitrile, and ferrous sulfate with a mass ratio of 1:4:2.5. The preparation method of the flocculant is to mix polyacrylamide, dimethyldiallylammonium chloride, methylvinylchlorosilane, and water. The mass ratio of polyacrylamide to water is 1:5. Then add the initiator and stir for 1 hour, heat up to 80 °C, and react for 4 h to obtain the flocculant. After adding the flocculant, stir at 150 r / min for 2 min, then stir at 70 r / min for 20 min, and let it stand for 90 min to obtain the primary treated sewage;

[0043] (2) The primary treated sewage is introduced into an aeration tank. The packing materials in the aeration tank include ceramsite, activated carbon, and polypropylene. The mass ratio of ceramsite, activated carbon, and polypropylene is 4:10:6.5. The diameters of ceramsite and activated carbon are 5 - 8 mm and 2 - 4 mm respectively. The gas-water ratio in the aeration tank is 6, and the optimal hydraulic load is 2.2 m 3 / (m 2 ·d), and the treatment time is 8 h to obtain the secondary treated sewage;

[0044] (3) The secondary treated sewage is introduced into a wetland treatment pool. Montmorillonite, kaolinite, and calcite are laid on the bottom of the wetland treatment pool. The mass ratio of montmorillonite, kaolinite, and calcite is 4.5:1.5:5. Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus are planted in the wetland treatment pool. The planting ratio of Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus is 1:4:9. The planting density of Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus is 28 plants / m 3 .

[0045] Comparative Example 2

[0046] (1) The sewage is filtered by a fence and then diverted to a flocculation tank. The flocculant is put into the flocculation tank at a dosage of 180 mg / L. The raw materials of the flocculant are composed of 6 parts of polyacrylamide, 3 parts of dimethyldiallylammonium chloride, 7 parts of methylvinylchlorosilane and 0.04 part of initiator by weight. The initiator is composed of hydrogen peroxide, azobisisobutyronitrile and ferrous sulfate with a mass ratio of 1:4:2.5. The preparation method of the flocculant is to mix polyacrylamide, dimethyldiallylammonium chloride, methylvinylchlorosilane and water. The mass ratio of polyacrylamide to water is 1:5. Add the initiator and stir for 1 hour, then heat up to 80 °C and react for 4 h to obtain the flocculant. After adding the flocculant, stir at 150 r / min for 2 min, then stir at 70 r / min for 20 min, and let it stand for 90 min to obtain the primary treated sewage;

[0047] (2) The primary treated sewage is introduced into an aeration tank. The packing in the aeration tank includes ceramsite, activated carbon and polypropylene. The mass ratio of ceramsite, activated carbon and polypropylene is 4:10:6.5. The diameters of ceramsite and activated carbon are 5 - 8 mm and 2 - 4 mm respectively. The air-water ratio in the aeration tank is 6, and the optimal hydraulic load is 2.2 m 3 / (m 2 ·d), and the treatment time is 8 h to obtain the secondary treated sewage;

[0048] (3) The secondary treated sewage is introduced into a wetland treatment pool, and a microbial preparation is sprinkled. The microbial preparation is composed of Actinoplanes mobilis, Alcaligenes viscolactis and Bacillus laterosporus with a mass ratio of 1:0.7:2.2. The dosage of the microbial preparation is 20 g / m 3 . Sandy soil is laid at the bottom of the wetland treatment pool. The planting ratio of Canna indica, Eremochloa ciliaris and Vallisneria natans in the wetland treatment pool is 1:1:1, and the planting density of Canna indica, Eremochloa ciliaris and Vallisneria natans is 24 plants / m 3 .

[0049] Experimental Example 1

[0050] The sewage treatment processes of Example 3 and Comparative Examples 1 - 2 were used for experiments. The experimental site was Xiuying District, Haikou City. A water quality analyzer was used for detection. Before treatment, the nitrogen content was 26.43 mg / L and the phosphorus content was 9.87 mg / L.

[0051] Name Example 3 Comparative Example 1 Comparative Example 2 Nitrogen content (mg / L) 2.54 5.32 4.88 Phosphorus content (mg / L) 0.35 0.74 0.59

[0052] The experimental results show that the sewage treatment process of the present invention can remove nitrogen, phosphorus and harmful impurities in urban sewage. After three treatment processes, the discharged sewage meets the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants". In Comparative Example 1, the microbial preparation was sprinkled in the flocculation tank, and for the untreated sewage, the pH value was not suitable for the reaction of the microbial preparation, resulting in a decrease in the sewage treatment effect. In Comparative Example 2, the layout of the wetland treatment pool and the types of aquatic plants planted were changed, resulting in a decrease in the sewage treatment effect. In the present invention, the microbial preparation is put into the wetland treatment pool. Due to the reasonable layout of the aquatic plants in the wetland treatment pool, the wetland treatment pool has the ability to reasonably adjust the water temperature and pH value, which is beneficial to improving the effect of the microbial preparation in removing harmful substances in water.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An urban sewage denitrification and phosphorus removal treatment process, characterized in that, It includes the following steps: (1) The sewage is filtered by a fence and then diverted to a flocculation tank, where a flocculant is added. The raw materials of the flocculant by weight include 5-7 parts of polyacrylamide, 2-4 parts of dimethyldiallylammonium chloride, 6-8 parts of methylvinylchlorosilane, and 0.03-0.05 parts of an initiator, to obtain the primary treated sewage. The initiator includes hydrogen peroxide, azobisisobutyronitrile, and ferrous sulfate with a mass ratio of 1:3-5:2-3; (2) The primary treated sewage is introduced into an aeration tank. The packing materials of the aeration tank include ceramsite, activated carbon, and polypropylene, to obtain the secondary treated sewage; (3) The secondary treated sewage is introduced into a wetland treatment pool, and a microbial agent is added. The microbial agent includes Actinoplanes mobilis, Alcaligenes viscolactis, and Bacillus laterosporus with a mass ratio of 1:0.5-0.8:2-2.

4. Montmorillonite, kaolinite, and calcite are laid on the bottom of the wetland treatment pool, and Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus are planted in the wetland treatment pool.

2. The urban sewage denitrification and phosphorus removal treatment process according to claim 1, characterized in that, In step (1), the dosage of the flocculant is 150-200 mg / L.

3. The urban sewage denitrification and phosphorus removal treatment process according to claim 1, characterized in that, In step (2), the air-water ratio of the aeration tank is 5 - 6, the hydraulic load is 2 - 2.4 m 3 / (m 2 ·d), and the treatment time is 6 - 8 h.

4. The urban sewage denitrification and phosphorus removal treatment process according to claim 1, wherein In step (2), the mass ratio of the ceramsite, activated carbon, and polypropylene is 3-5:8-12:6-7.

5. The urban sewage denitrification and phosphorus removal treatment process according to claim 1, characterized in that In step (3), the mass ratio of the montmorillonite, kaolinite, and calcite is 4-5:1-2:3-6.

6. The urban sewage denitrification and phosphorus removal treatment process according to claim 1, characterized in that In step (3), the planting ratio of the Eichhornia crassipes, Sagittaria trifolia, and Iris pseudacorus is 1:3-5:8-10.

7. The urban sewage denitrification and phosphorus removal treatment process according to claim 6, characterized in that, The planting density of Eichhornia crassipes, Sagittaria trifolia and Iris pseudacorus is 20 - 35 plants / m 3 .

8. The urban sewage denitrification and phosphorus removal treatment process according to claim 1, wherein The dosage of the microbial agent is 15 - 25 g / m 3 .