CN111333227A

CN111333227A - Municipal sewage treatment process

Info

Publication number: CN111333227A
Application number: CN202010213131.3A
Authority: CN
Inventors: 余丽莉; 李杰业; 成永辉; 冯华
Original assignee: Guangzhou Huajing Construction Co ltd
Current assignee: Guangzhou Huajing Construction Co ltd
Priority date: 2020-03-24
Filing date: 2020-03-24
Publication date: 2020-06-26

Abstract

The invention relates to the technical field of sewage treatment, and relates to a municipal sewage treatment process, which comprises the following steps: step (1), primary treatment: filtering; step (2), secondary treatment: standing; step (3), preparing a flocculating agent; step (4), three-stage treatment: adding the flocculating agent prepared in the step (3) into the intermediate sewage obtained by separation in the step (2), stirring, separating supernatant after sedimentation flocs formed by the flocculating agent and the dirt in the intermediate sewage are completely precipitated, and removing the sedimentation flocs to obtain purified water, namely finishing the treatment of the municipal sewage; the flocculant comprises the following components in parts by mass: 70-80 parts of polyacrylamide; 15-20 parts of a coagulant aid; 30-45 parts of water; 5-10 parts of clay; 1-3 parts of formononetin; 0.5-1.5 parts of hydroxyethyl hexahydro-s-triazine. The invention has the effect that the adsorbed dirt is not easy to separate from the settled floc, so that the dirt content in the treated purified water is not easy to rise.

Description

Municipal sewage treatment process

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a municipal sewage treatment process.

Background

At present, with the acceleration of the urbanization and industrialization process, the production capacity is continuously increased, the pollution is increasingly serious, and the sustainable development of the urban society and economy is seriously restricted. The pollution problem of municipal sewage is increasingly prominent in the process of urbanization and industrialization, and becomes an important factor for restricting the sustainable development of urban socioeconomic performance. Therefore, the problem of properly treating municipal sewage is very important.

The existing municipal sewage treatment process generally comprises primary treatment, secondary treatment and tertiary treatment, wherein the primary treatment is to filter solid garbage sundries in the municipal sewage; the second-stage treatment is aeration treatment through an aeration tank, an aeration fan and a special aeration device are used for supplying oxygen to the aeration tank, and colloid and soluble organic matters in the sewage are removed; and the third-stage treatment is to put a flocculating agent into the water to remove nutrients and other refractory substances in the water.

The above prior art solutions have the following drawbacks: the sedimentation floc structure formed by combining the existing flocculating agent and the sewage in water is loose, so that the sewage adsorbed by the flocculating agent is easily separated from the sedimentation floc and returns to the sewage again, the sewage content in the sewage rises again, the sewage treatment effect of the flocculating agent is easily influenced, and the improvement space is still left.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a municipal sewage treatment process.

The above object of the present invention is achieved by the following technical solutions:

a municipal sewage treatment process comprises the following steps:

step (1), primary treatment: filtering the municipal sewage to be treated by a filter piece to remove insoluble impurities in the municipal sewage to obtain pretreated sewage;

step (2), secondary treatment: standing the pretreated sewage in the step (1) for 40-60min, and separating out supernatant to obtain intermediate sewage;

step (3), preparing a flocculating agent: adding each component of the flocculating agent into a reaction container, stirring and mixing uniformly, drying, granulating and forming to obtain the flocculating agent;

step (4), three-stage treatment: adding the flocculating agent prepared in the step (3) into the intermediate sewage obtained by separation in the step (2), stirring, separating supernatant after sedimentation flocs formed by the flocculating agent and the dirt in the intermediate sewage are completely precipitated, and removing the sedimentation flocs to obtain purified water, namely finishing the treatment of the municipal sewage;

the flocculant comprises the following components in parts by mass:

70-80 parts of polyacrylamide;

15-20 parts of a coagulant aid;

30-45 parts of water;

5-10 parts of clay;

1-3 parts of formononetin;

0.5-1.5 parts of hydroxyethyl hexahydro-s-triazine.

Through adopting above-mentioned technical scheme, through adopting clay, formononetin and hydroxyethyl hexahydro sym-triazine to cooperate mutually, be favorable to improving the adsorptivity and the settleability of flocculating agent for filth in the municipal administration sewage is absorbed completely and is formed the settlement flocculating constituent and sink more easily by the flocculating agent, thereby be favorable to reducing total phosphorus content, ammonia nitrogen content and dissolved oxygen content in the water purification after accomplishing that subsides better, make the decontamination effect of flocculating agent better.

Through adopting clay, formononetin and hydroxyethyl hexahydro s-triazine to cooperate mutually, still be favorable to improving the stability that the filth combines the settlement floc that forms with the flocculating agent for the filth is difficult to separate out and the heavy sewage that returns from settling the floc more, thereby makes the decontamination effect of flocculating agent lasting long-term more, makes the content of total phosphorus content, ammonia nitrogen content and dissolved oxygen in the water purification that the processing was accomplished and is obtained be difficult to the rebound again more.

Through the mutual synergistic cooperation of the clay, formononetin and hydroxyethyl hexahydro-s-triazine, the settled flocs which are settled are favorably decomposed into sludge better, so that the settled flocs can be reused to be decomposed into fertilizers after being separated, nitrogen, phosphorus and the like in the sewage can be reused to provide nutrient substances for the growth of plants, the pollution of the sewage to the environment is favorably reduced, and the utilization rate of resources is favorably improved better.

By adopting the flocculating agent to treat sewage, the total phosphorus content, ammonia nitrogen content and dissolved oxygen content in the sewage can be reduced without aeration, so that an aeration fan and an aeration device are not required to be maintained, the treatment cost of municipal sewage is favorably reduced, and the economic benefit is favorably improved.

The present invention in a preferred example may be further configured to: the adding amount of the flocculating agent is 80mg/L-100 mg/L.

By adopting the technical scheme, the flocculant is favorably combined with the dirt in the sewage to form a sedimentation floc and subside by controlling the adding amount of the flocculant, the decontamination effect of the flocculant is favorably improved, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are lower.

The present invention in a preferred example may be further configured to: in the step (3), after the flocculating agent is put in, the mixture is stirred for 8-10min at the rotating speed of 200-250 r/min.

By adopting the technical scheme, the stirring speed and the stirring time after the flocculant is put in are controlled, so that the flocculant can better adsorb dirt in sewage and form a sedimentation floc to settle, the decontamination effect of the flocculant can be better improved, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the purified water after treatment are lower.

The present invention in a preferred example may be further configured to: the coagulant aid is prepared from ferrous sulfate and ferric chloride in a mass part ratio of (2-6): 4-8, and mixing uniformly.

By adopting the technical scheme, the ferrous sulfate and the ferric chloride are mutually cooperated and matched in a certain dosage proportion to form the coagulant aid, so that the coagulant aid is favorable for better promoting the decontamination effect of the flocculant, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are lower.

The present invention in a preferred example may be further configured to: the flocculant also comprises the following components in parts by mass:

0.3-0.5 part of madecassoside.

Through adopting above-mentioned technical scheme, through adding the madecassoside, be favorable to promoting the clay better, formononetin and hydroxyethyl hexahydro s-triazine's the cooperative coordination each other, thereby be favorable to improving the adsorption efficiency and the settling property of flocculating agent better, make the filth in the sewage be adsorbed by the flocculating agent completely more easily and form and subside the floc in order to subside, and then be favorable to improving the decontamination effect of flocculating agent better, make the total phosphorus content in the purified water after accomplishing the processing, the ammonia nitrogen content and the content of dissolved oxygen lower.

Meanwhile, the method is favorable for better improving the stability of the sedimentation flocs, so that the sewage is less likely to be separated from the sedimentation flocs and returns to the sewage again, the decontamination effect of the flocculant is more durable, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are less likely to rise.

In addition, the decomposition of the settled flocs is facilitated, so that nutrient substances in the settled flocs are more easily converted into fertilizers and absorbed by plants, the utilization rate of resources is favorably improved, and the survival rate of the plants is favorably improved.

1-3 parts of polyethylene glycol.

By adopting the technical scheme, the coating performance of the flocculant is favorably improved by adding polyethylene glycol, so that the stability of the sedimentation flocs formed by combining the flocculant and the sewage in the sewage is higher, the flocculant is favorably prevented from being separated from the sedimentation flocs and returned to the sewage again, the decontamination effect of the flocculant is more durable and long-acting, and the content of total phosphorus, ammonia nitrogen and dissolved oxygen in the treated purified water is less prone to being increased.

0.5-1 part of vaseline.

By adopting the technical scheme, the vaseline and the polyethylene glycol are added to be matched with each other in a synergistic manner, so that the coating film forming performance of the flocculant is favorably improved, the stability of a sedimentation floc formed by combining the flocculant and sewage is higher, the sewage is favorably inhibited from being separated from the sedimentation floc and returned to the purified water again, the decontamination effect of the flocculant is longer and longer lasting, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the purified water after treatment are further enabled to be less prone to rising.

0.1-0.3 part of guar gum.

By adopting the technical scheme, the guar gum is added, so that the stability of the settled flocs is favorably improved, the dirt is not easily separated from the settled flocs and returns to the purified water again, the lasting and long-acting property of the decontamination effect of the flocculant is favorably improved, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the purified water after treatment are not easily increased.

1-1.5 parts of methyl cellulose.

By adopting the technical scheme, the decomposition of the settled flocs is favorably promoted by adding the methyl cellulose, so that the settled flocs are more easily decomposed into fertilizers and provide nutrient substances for plant growth, the utilization rate of resources is favorably improved, and the survival rate of plants is improved.

0.3-0.5 part of carbomer.

By adopting the technical scheme, the carbomer is added, so that the adsorption performance of the flocculant can be better improved, dirt in sewage can be more easily and completely adsorbed by the flocculant, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in purified water after treatment can be better reduced.

In summary, the invention includes at least one of the following beneficial technical effects:

1. the sewage is treated by adopting the flocculating agent in the invention, aeration operation is not needed, the operation is simple and convenient, and the maintenance cost of the device for aeration is saved;

2. the clay, formononetin and hydroxyethyl hexahydro-s-triazine are mutually cooperated to form a flocculating agent and used for treating sewage, so that the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are favorably reduced, the stability of settled flocs is favorably improved, dirt is not easy to separate from the settled flocs again and return to the purified water, the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the purified water are not easy to rise again, and the settled flocs can be reused to decay into fertilizers, so that the utilization rate of resources is favorably improved;

3. by adopting the synergistic cooperation of the ferrous sulfate and the ferric trichloride in a certain dosage proportion, the decontamination effect of the flocculating agent is favorably promoted, so that the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are lower.

Drawings

FIG. 1 is a process flow diagram of the municipal wastewater treatment process of the invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

In the following examples, polyacrylamide having a SD mesh number of 60 from Henan Water equation Water purifying materials Co., Ltd is used.

In the following examples, ferrous sulfate from the national color chemical company ltd is used as ferrous sulfate.

In the following examples, iron trichloride from Shenyang Ketou chemical Co., Ltd was used.

In the following examples, the clay used is Shijiazhuang Mayun building materials Co., Ltd. (product number 3).

In the following examples, formononetin is formononetin having a product number of 375, manufactured by Shanxi Yuning Biotech Co., Ltd.

In the following examples, hydroxyethyl hexahydro-s-triazine from Astraziaceae Vijin environmental protection science and technology, Inc. is used.

In the following examples, madecassoside is madecassoside from Hubei Kangxinyuan pharmaceutical chemical Co., Ltd, having a product number of 005.

In the following examples, the polyethylene glycol used is PEG-400, model number of Shenzhen Sirikay trade company Limited.

In the following examples, vaseline was supplied from Zhengzhou Zhongrun chemical products Co., Ltd, model number CP-2015.

In the following examples, guar gum from Hainan Jiqian Biotech Inc. was used.

In the following examples, the methylcellulose used was YYSJC0098 available from caicheng biotechnology limited of yueyang.

In the following examples, carbomer 940, available from Wuhanxin Confucian chemical Co., Ltd, under the designation 20191059, was used.

Example 1

A municipal sewage treatment process comprises the following steps:

step (1), primary treatment, which comprises the following specific steps:

sampling in municipal drainage ditches on a road with 19 # large roads constructed in overseas areas in Guangzhou city as test raw water, taking 10L of test raw water as a sample, passing the test raw water sample through a filter screen with 200-mesh aperture, and filtering large-particle insoluble impurities such as garbage, stones and the like in the test raw water sample to obtain pretreated sewage.

And (2) performing secondary treatment, which specifically comprises the following steps:

and (2) introducing the pretreated sewage obtained in the step (1) into a secondary sedimentation tank, standing for 40min, and pumping the supernatant into a tertiary treatment tank to separate the supernatant from the lower suspension to obtain intermediate sewage.

And (3) preparing a flocculating agent, which comprises the following specific steps:

adding 75kg of polyacrylamide, 20kg of coagulant aid and 37.5kg of water into a 200L stirring kettle, raising the temperature to 50 ℃, stirring at the rotating speed of 120r/min to dissolve the polyacrylamide to form a solution, adding 15kg of clay, 2kg of formononetin and 1kg of hydroxyethyl hexahydro-s-triazine while stirring, and forming a semi-finished product after uniformly stirring.

And then, putting the semi-finished product into a drying oven for drying, controlling the temperature of the drying oven to be 85 ℃, and controlling the drying time to be 10 hours. And after the semi-finished product is completely dried, adding the semi-finished product into a granulator for granulation and molding, and controlling the particle size of granules obtained by granulation to be 1250 meshes to obtain the flocculant.

In this embodiment, the coagulant aid is ferrous sulfate.

And (4) performing three-stage treatment, which specifically comprises the following steps:

and (3) adding 750mg of the flocculant prepared in the step (3) into the intermediate sewage separated in the step (2) in the third-stage treatment tank, stirring at the rotating speed of 150r/min for 12min, separating out supernatant after the flocculant and sedimentation flocs formed by the sewage in the intermediate sewage are completely precipitated, and removing the sedimentation flocs to obtain purified water, namely finishing the treatment of the municipal sewage.

Example 2

The difference from example 1 is that:

and (3) standing the pretreated sewage in the step (2) for 50 min.

The amount of each component added in the step (3) is as follows:

70kg of polyacrylamide; 15kg of coagulant aid; 45kg of water; 17.5kg of clay; 1kg of formononetin; 1.5kg of hydroxyethyl hexahydro-s-triazine.

And (4) controlling the temperature of the drying oven to be 90 ℃ in the step (3), and controlling the drying time to be 9 h.

Example 3

The difference from example 1 is that:

and (3) standing the pretreated sewage in the step (2) for 60 min.

The amount of each component added in the step (3) is as follows:

80kg of polyacrylamide; 17.5kg of coagulant aid; 30kg of water; 20kg of clay; 3kg of formononetin; 0.5kg of hydroxyethyl hexahydro-s-triazine.

And (3) controlling the temperature of the drying oven to be 95 ℃ and controlling the drying time to be 8 h.

Example 4

The difference from example 1 is that:

and (3) standing the pretreated sewage in the step (2) for 45 min.

The amount of each component added in the step (3) is as follows:

74kg of polyacrylamide; 18kg of coagulant aid; 40kg of water; 16kg of clay; 1.5kg of formononetin; 1.1kg of hydroxyethyl hexahydro-s-triazine.

In the step (3), the temperature of the drying oven is controlled to be 88 ℃, and the drying time is controlled to be 9.5 h.

Example 5

The difference from example 4 is that: the adding amount of the flocculating agent in the step (4) is 1050 mg.

Example 6

The difference from example 4 is that: the adding amount of the flocculating agent in the step (4) is 800 mg.

Example 7

The difference from example 4 is that: the adding amount of the flocculating agent in the step (4) is 1000 mg.

Example 8

The difference from example 4 is that: the adding amount of the flocculating agent in the step (4) is 900 mg.

Example 9

The difference from example 4 is that: after the flocculating agent is put in, the mixture is stirred for 5min at the rotating speed of 300 r/min.

Example 10

The difference from example 4 is that: after the flocculating agent is put in, the mixture is stirred for 10min at the rotating speed of 200 r/min.

Example 11

The difference from example 4 is that: and (5) after the flocculating agent is added, stirring for 8min at the rotating speed of 250 r/min.

Example 12

The difference from example 4 is that: after the flocculant is added, stirring is carried out for 9min at the rotating speed of 230 r/min.

Example 13

The difference from example 4 is that: the coagulant aid is ferric chloride.

Example 14

The difference from example 4 is that: the coagulant aid is prepared by mixing ferrous sulfate and ferric trichloride in a mass ratio of 1: 9, and mixing the components uniformly.

Example 15

The difference from example 4 is that: the coagulant aid is prepared from ferrous sulfate and ferric trichloride in a mass ratio of 7: 3, and mixing the components uniformly.

Example 16

The difference from example 4 is that: the coagulant aid is prepared from ferrous sulfate and ferric trichloride in a mass ratio of 2: 8, and mixing the components uniformly.

Example 17

The difference from example 4 is that: the coagulant aid is prepared from ferrous sulfate and ferric trichloride in a mass ratio of 6: 4, and mixing uniformly.

Example 18

The difference from example 4 is that: the coagulant aid is prepared from ferrous sulfate and ferric trichloride in a mass ratio of 3: 7, and mixing the components uniformly.

Example 19

The difference from example 4 is that: 0.3kg of madecassoside is added in the step (3) while stirring.

Example 20

The difference from example 4 is that: 0.5kg of madecassoside is added in the step (3) while stirring.

Example 21

The difference from example 4 is that: in the step (3), 1kg of polyethylene glycol is added while stirring.

Example 22

The difference from example 4 is that: in the step (3), 3kg of polyethylene glycol is added while stirring.

Example 23

The difference from example 4 is that: 0.5kg of vaseline is added in the step (3) while stirring.

Example 24

The difference from example 4 is that: and (3) adding 1kg of vaseline while stirring.

Example 25

The difference from example 4 is that: 1kg of polyethylene glycol and 1kg of vaseline are added while stirring in the step (3).

Example 26

The difference from example 4 is that: 3kg of polyethylene glycol and 0.5kg of vaseline are added while stirring in the step (3).

Example 27

The difference from example 4 is that: 0.1kg of guar gum is added in the step (3) while stirring.

Example 28

The difference from example 4 is that: 0.3kg of guar gum is added in the step (3) while stirring.

Example 29

The difference from example 4 is that: in the step (3), 1kg of methylcellulose is added while stirring.

Example 30

The difference from example 4 is that: in the step (3), 1.5kg of methylcellulose is added while stirring.

Example 31

The difference from example 4 is that: 0.3kg of carbomer is also added in the step (3) while stirring.

Example 32

The difference from example 4 is that: 0.5kg of carbomer is also added in the step (3) while stirring.

Example 33

The difference from example 4 is that:

the coagulant aid in the step (3) is prepared from ferrous sulfate and ferric trichloride in a mass part ratio of 3: 7, and mixing the components uniformly.

0.3kg of madecassoside, 3kg of polyethylene glycol, 0.5kg of vaseline, 0.1kg of guar gum, 1kg of methyl cellulose and 0.3kg of carbomer are added in the step (3) while stirring.

The adding amount of the flocculating agent in the step (4) is 900mg, and after the flocculating agent is added, the mixture is stirred for 9min at the rotating speed of 230 r/min.

Example 34

Example 33 differs in that:

the amount of each component added while stirring in step (3) is as follows:

0.5kg of madecassoside; 1kg of polyethylene glycol; 1kg of vaseline; 0.3kg of guar gum; 1.5kg of methyl cellulose; carbomer 0.5 kg.

Example 35

Example 33 differs in that:

the amount of each component added while stirring in step (3) is as follows:

0.4kg of madecassoside; 2kg of polyethylene glycol; 0.75kg of vaseline; 0.2kg of guar gum; 1.25kg of methyl cellulose; carbomer 0.4 kg.

Example 36

Example 33 differs in that:

the amount of each component added while stirring in step (3) is as follows:

0.35kg of madecassoside; 2.5kg of polyethylene glycol; 0.6kg of vaseline; 0.15kg of guar gum; 1.1kg of methyl cellulose; carbomer 0.45 kg.

Comparative example 1

The difference from example 4 is that: in the step (3), no clay, formononetin and hydroxyethyl hexahydro-s-triazine are added.

Comparative example 2

The difference from example 4 is that: no clay is added in the step (3).

Comparative example 3

The difference from example 4 is that: formononetin is not added in the step (3).

Comparative example 4

The difference from example 4 is that: in the step (3), hydroxyethyl hexahydro-s-triazine is not added.

Experiment 1

After the test raw water is sampled, the original total phosphorus content (mg/L) in the test raw water is detected according to GB11893-1989 ammonium molybdate spectrophotometry for measuring total phosphorus in water, the original ammonia nitrogen content (mg/L) in the test raw water is detected according to HJ535-2009 Nashin's reagent spectrophotometry for measuring ammonia nitrogen in water, and the original dissolved oxygen content (mg/L) in the test raw water is detected according to GB7489-1987 iodine content method for measuring dissolved oxygen in water. Wherein the original total phosphorus content is 863.48mg/L, the original ammonia nitrogen content is 3329.75mg/L, and the original dissolved oxygen content is 1734.36 mg/L.

After the sedimentation flocs in the above examples and comparative examples are completely precipitated, the total phosphorus content (mg/L) in the mixed liquid of the sedimentation flocs and the supernatant after the treatment in the above examples and comparative examples is detected according to GB11893-1989 ammonium molybdate spectrophotometry for measuring total phosphorus in water, the ammonia nitrogen content (mg/L) in the mixed liquid of the sedimentation flocs and the supernatant after the treatment in the above examples and comparative examples is detected according to HJ535-2009 nano-meter for measuring ammonia nitrogen in water, and the dissolved oxygen content (mg/L) in the mixed liquid of the sedimentation flocs and the supernatant after the treatment in the above examples and comparative examples is detected according to GB7489-1987 iodine content for measuring dissolved oxygen in water. And then standing the mixed solution of the treated sedimentation flocs and the supernatant for 12h, and detecting the total phosphorus content (mg/L), the ammonia nitrogen content (mg/L) and the dissolved oxygen content (mg/L) in the mixed solution every 2 h.

Experiment 2

The settled flocs separated in the above examples and comparative examples were collected, then buried pits of 30cm by 20cm were dug in the soil, 10g of the settled flocs collected in the above examples and comparative examples were buried in different buried pits, respectively, soil was backfilled, appropriate amount of water was added, the temperature in the soil was controlled at 40 ℃, after 4 months of decomposition, the soil in the buried pits was dug together and stirred uniformly, and a fertilizer was prepared.

In addition, 20 annual ginkgo seedlings were planted according to each of the examples and comparative examples, and the seedlings according to the examples and comparative examples were fertilized with the fertilizer, each seedling was fertilized once every week with a fertilizing amount of 100g, temperature, moisture and light conditions being consistent and adjusted according to actual conditions, and after 3 months, the survival number (plants) of the seedlings according to the examples and comparative examples was recorded.

The data for experiment 1 is shown in Table 1 and the data for experiment 2 is shown in Table 2.

TABLE 1

TABLE 2

According to the comparison of the data of the embodiments 4 to 8 in the table 1, the flocculant is beneficial to better adsorb the dirt in the sewage by controlling the adding amount of the flocculant, so that the dirt in the sewage is more easily and completely adsorbed by the flocculant to form a settled floc to be precipitated, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are lower.

According to the comparison of the data of the embodiment 4 and the embodiments 9-12 in the table 1, the flocculant can be favorably used for better adsorbing the dirt in the sewage by controlling the stirring speed and the stirring time, so that the dirt in the sewage can be more easily and completely absorbed and can form a sedimentation floc precipitate, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are lower.

According to the comparison of the data of the example 4 and the examples 13-18 in the table 1, the composition of the coagulant aid and the dosage ratio of the components are controlled, so that the adsorption effect of the flocculant is favorably promoted, the dirt in the sewage is more easily and completely absorbed, and the settled floc is formed and precipitated, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are favorably reduced.

According to the comparison of the data of the embodiment 4 and the embodiments 19 to 20 in the table 1, the addition of the madecassoside is favorable for better promoting the mutual synergistic cooperation of the clay, the formononetin and the hydroxyethyl hexahydro-s-triazine, so that the adsorption performance and the sedimentation performance of the flocculant are better improved, the dirt in the sewage is more easily and completely absorbed and forms sedimentation flocs to precipitate, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are lower; meanwhile, the method is beneficial to better improving the stability of the settled flocs, so that the dirt is more difficult to separate from the settled flocs and returns to the purified water again, the decontamination effect of the flocculant is more durable, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the purified water are more difficult to return; in addition, the decomposition of the sedimentation flocs is promoted better, so that the sedimentation flocs are decomposed into fertilizers better, nutrient substances are provided for the growth of plants, the survival rate of the plants is improved, and the utilization rate of resources is improved better.

According to the comparison of the data of the embodiment 4 and the embodiments 21 to 26 in the table 1, the polyethylene glycol is added independently, which is beneficial to improving the coating performance of the flocculant, so that the stability of the settled floc is higher, the dirt is less prone to being separated from the settled floc, and the settled floc is returned to the purified water again, so that the decontamination effect of the flocculant is more durable and long-acting, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the purified water are less prone to being increased. The vaseline and the polyethylene glycol are added to be matched with each other in a synergistic manner, so that the flocculant can better form a film and coat dirt, the stability of the settled floc can be better improved, the dirt is less prone to being separated from the settled floc and can be returned to the purified water again, the decontamination effect of the flocculant is longer and longer-lasting, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the purified water are less prone to being increased. And when the vaseline is added independently, the coating performance of the flocculant is hardly influenced.

According to the comparison of the data of the embodiment 4 and the embodiments 27 to 28 in the table 1, the guar gum is added, so that the stability of the settled flocs is improved, the dirt is not easy to separate from the settled flocs, and the settled flocs are returned to the purified water again, the decontamination effect of the flocculant is lasting and long-acting, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the purified water are not easy to increase.

According to the comparison of the data of example 4 and examples 29-30 in table 1, the decomposition of the settled flocs is promoted better by adding methylcellulose, so that the nutrients in the fertilizer formed by the decomposition of the settled flocs are absorbed by the plants more easily, and the survival rate of the plants is improved better.

According to the comparison of the data of the example 4 and the examples 31-32 in the table 1, by adding carbomer, the adsorption performance and the sedimentation performance of the flocculant are improved better, so that the dirt in the sewage is adsorbed completely and precipitated by forming sedimentation floc, the decontamination effect of the flocculant is improved better, and the total phosphorus content, the ammonia nitrogen content and the dissolved oxygen content in the treated purified water are lower.

According to the comparison of the data of the example 4 and the comparative examples 1 to 4 in the table 1, only when the clay, formononetin and hydroxyethyl hexahydro-s-triazine are cooperated with each other, the adsorption performance and the sedimentation performance of the flocculant can be better improved, the stability of the sedimentation floc can be better improved, the decay of the sedimentation floc can be promoted, the decontamination effect of the flocculant can be better improved, the utilization rate of resources can be better improved, and any component is lacked, so that the adsorption performance, the sedimentation performance and the stability of the sedimentation floc are greatly influenced.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims

1. A municipal sewage treatment process is characterized in that: the method comprises the following steps:

the flocculant comprises the following components in parts by mass:

70-80 parts of polyacrylamide;

15-20 parts of a coagulant aid;

30-45 parts of water;

5-10 parts of clay;

1-3 parts of formononetin;

0.5-1.5 parts of hydroxyethyl hexahydro-s-triazine.

2. The municipal sewage treatment process of claim 1, wherein: the adding amount of the flocculating agent is 80mg/L-100 mg/L.

3. The municipal sewage treatment process of claim 2, wherein: in the step (3), after the flocculating agent is put in, the mixture is stirred for 8-10min at the rotating speed of 200-250 r/min.

4. The municipal sewage treatment process of any one of claims 1 to 3, wherein: the coagulant aid is prepared from ferrous sulfate and ferric chloride in a mass part ratio of (2-6): 4-8, and mixing uniformly.

5. The municipal sewage treatment process of any one of claims 1 to 3, wherein: the flocculant also comprises the following components in parts by mass:

0.3-0.5 part of madecassoside.

6. The municipal sewage treatment process of any one of claims 1 to 3, wherein: the flocculant also comprises the following components in parts by mass:

1-3 parts of polyethylene glycol.

7. The municipal sewage treatment process of claim 6, wherein: the flocculant also comprises the following components in parts by mass:

0.5-1 part of vaseline.

8. The municipal sewage treatment process of any one of claims 1 to 3, wherein: the flocculant also comprises the following components in parts by mass:

0.1-0.3 part of guar gum.

9. The municipal sewage treatment process of any one of claims 1 to 3, wherein: the flocculant also comprises the following components in parts by mass:

1-1.5 parts of methyl cellulose.

10. The municipal sewage treatment process of any one of claims 1 to 3, wherein: the flocculant also comprises the following components in parts by mass:

0.3-0.5 part of carbomer.