Treatment method of salt-containing wastewater in coal chemical industry

Abstract

The invention relates to the technical field of wastewater discharge, and particularly discloses a treatment method of coal chemical industry salt-containing wastewater. The invention provides a treatment method of coal chemical industry salt-containing wastewater. The treatment method comprises the following specific steps: pretreatment, advanced oxidation treatment and biochemical treatment, the advanced oxidation treatment comprises the following steps: the concentrated water enters a Fenton reaction tank, the pH value is adjusted to 2.8-3.2, then hydrogen peroxide and ferrous salt spermine are sequentially added, and the reaction time is 3-5 h; the biochemical treatment comprises the following steps: enabling effluent to enter a biochemical unit, adding a salt-tolerant microbial agent and a microbial growth promoter, and treating for 72-120 hours; the microbial growth promoter comprises calcium salt, spermidine, fatty acid methyl ester sodium sulfonate, inorganic phosphoric acid substances and organic phosphoric acid substances. By utilizing the treatment method provided by the invention, COD (Chemical Oxygen Demand), ammonia nitrogen, TDS (Total Dissolved Solids) and other impurities in the coal chemical industry high-salinity wastewater can be effectively removed, and an excellent wastewater treatment effect is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater discharge, and in particular to a method for treating salt-containing wastewater in coal chemical industry. Background Art

[0002] Coal chemical wastewater discharge is an important research topic in the current field of industrial wastewater treatment. With the rapid development of the coal chemical industry, the problem of wastewater discharge has become increasingly prominent, posing a severe challenge to environmental protection and sustainable development. At present, research on coal chemical wastewater discharge mainly focuses on wastewater treatment technology, wastewater zero discharge technology and resource utilization.

[0003] Coal chemical wastewater has complex composition and contains high concentrations of organic matter, heavy metal ions and other pollutants, making it difficult to treat. Traditional wastewater treatment methods such as physical, chemical and biological methods have certain limitations in treating coal chemical wastewater. Therefore, researchers are constantly exploring new wastewater treatment technologies, such as biofilm reactors and advanced oxidation technologies, to improve the efficiency and scope of wastewater treatment.

[0004] Wastewater zero discharge technology: In order to achieve zero discharge of coal chemical wastewater, researchers are committed to developing efficient wastewater zero discharge technology. These technologies usually include pretreatment, membrane concentration, evaporation and crystallization to maximize the treatment and reuse of various components in wastewater. However, due to the complexity of coal chemical wastewater components and the limitations of treatment technology, the actual application effect of zero discharge technology still needs to be further improved.

[0005] Resource utilization: Coal chemical wastewater contains many valuable components, such as salts, organic matter, etc. Through reasonable treatment and recycling, these components can be utilized as resources, reducing the cost of wastewater treatment and promoting the recycling of resources. At present, resource utilization has become one of the important research directions in the field of coal chemical wastewater treatment.

[0006] Although the research on coal chemical wastewater discharge has made certain progress, the following problems still exist: High treatment cost: A large amount of energy and chemical agents are consumed in the process of coal chemical wastewater treatment, resulting in high treatment costs. This limits the widespread application and promotion of wastewater treatment technology. Low treatment efficiency: Due to the complexity of the components of coal chemical wastewater, traditional wastewater treatment methods often cannot achieve the ideal treatment effect. Although the development and application of new technologies have improved, they still need to be further optimized and improved. Technical bottleneck: There are still technical bottlenecks in the actual application of zero-discharge technology for coal chemical wastewater, such as membrane pollution, evaporator scaling and other problems, which affect the stability and reliability of the technology. Low degree of resource utilization: At present, the recovery rate of valuable components in coal chemical wastewater is low, and a large amount of resources are wasted. How to improve the degree of resource utilization and achieve wastewater reduction, resource utilization and harmlessness is still an urgent problem to be solved.

[0007] In summary, although the research status of coal chemical wastewater discharge has achieved certain results, it still faces many challenges and problems. In the future, it is necessary to further strengthen research efforts and explore more efficient, economical and environmentally friendly wastewater treatment technologies. Summary of the invention

[0008] In order to solve the above technical problems, the present application provides a method for treating salt-containing wastewater in coal chemical industry.

[0009] The present application provides a method for treating salt-containing wastewater from coal chemical industry, which specifically comprises the following steps in sequence: pretreatment, advanced oxidation treatment, biochemical treatment, and post-treatment; The specific steps of the advanced oxidation treatment are: the pretreated concentrated water enters the Fenton reaction tank, the pH value is adjusted to 2.8-3.2, and then hydrogen peroxide with a final concentration of 120-180 mg / L, 5-15 mg / L of ferrous salt, and 0.2-0.6 mg / L of spermine are added in sequence, and the reaction time is 3-5 hours; The specific steps of the biochemical treatment are: the effluent from the advanced oxidation treatment enters the biochemical unit, and a salt-tolerant bacteria agent and a microbial growth promoter are added, and the treatment time is 72-120 hours; The dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour are 20-50 mg / L; The dosage of the microbial growth promoter is 2-12 mg / L to the solid-liquid ratio of the wastewater treated per hour; The microbial growth promoter specifically comprises the following components in parts by weight: 15-20 parts by weight of calcium salt, 4-8 parts by weight of spermidine, 4-8 parts by weight of sodium fatty acid methyl ester sulfonate, 1-4 parts by weight of inorganic phosphoric acid substances, and 0.1-0.5 parts by weight of organic phosphonic acid substances.

[0010] By using the treatment method provided in this application, the coal chemical industry's saline wastewater is subjected to pretreatment, advanced oxidation treatment, biochemical treatment, and post-treatment steps in sequence, and the types and amounts of salt-tolerant bacteria agents and microbial growth promoters in the biochemical treatment process are controlled. This can effectively remove the impurities such as COD, ammonia nitrogen, TDS, and nitrate ions in the coal chemical industry's high-salt wastewater, achieving excellent wastewater treatment effects.

[0011] The inventive idea of ​​the microbial growth promoter in this application is that calcium ions have an important influence on the growth of microorganisms. In the process of wastewater treatment, an appropriate amount of calcium ions can promote the metabolic activity of microorganisms and improve their ability to treat wastewater; calcium salts can also adjust the pH value of wastewater to provide a suitable growth environment for microorganisms. Spermidine can enhance the stress resistance of microorganisms and help them survive and reproduce in the harsh environment during wastewater treatment; it can also act as a signal factor to enhance the expression of antioxidant enzyme-related genes, thereby increasing the content of antioxidant enzymes in microbial cells, enhancing their ability to remove reactive oxygen in the body, and alleviating stress oxidative damage to the cytoplasmic membrane; in addition, spermidine can also combine with antioxidant enzymes to directly increase enzyme activity and further enhance the antioxidant capacity of microorganisms. In the process of sewage treatment, the addition of sodium fatty acid methyl ester sulfonate can enhance the activity of microorganisms in the wastewater treatment system, and can be quickly decomposed and utilized by microorganisms, thereby improving the metabolic rate and treatment efficiency of microorganisms. Inorganic phosphoric acid can directly provide a phosphorus source for microorganisms, promoting their normal growth and metabolism; organic phosphonic acid can release phosphorus through the decomposition of microorganisms for their use; an appropriate amount of phosphorus can promote the activity of microorganisms and improve their ability to degrade organic pollutants. The addition of inorganic phosphoric acid and organic phosphonic acid can increase the ATP content in microbial cells, thereby improving their energy level and metabolic activity; the addition of inorganic phosphoric acid and organic phosphonic acid can enhance the stability of the system, improve the resistance of microorganisms to adverse conditions, and ensure the continuous and stable operation of wastewater treatment. By accurately designing the dosage of each raw material component as a microbial growth promoter, the treatment effect of salt-tolerant bacteria on wastewater can be effectively improved.

[0012] Preferably, the specific steps of the pretreatment are: the coal chemical saline wastewater enters the reaction zone of the high-density clarification tank, calcium hydroxide is added to adjust the pH value to 10.5-11.0, and then sodium carbonate with a final concentration of 1.8-2.2 g / L, PFS with a final concentration of 8-12 mg / L for coagulation, and PAM with a final concentration of 0.7-1.5 mg / L for coagulation aid. After sufficient coagulation, it enters the clarification zone for precipitation, and finally hydrochloric acid is added at the outlet of the clarification tank to adjust the pH to about 7; the water passes through the filter tank to remove suspended matter and colloidal particles in the water.

[0013] Preferably, after the advanced oxidation treatment, the COD content in the water is ≤1100 mg / L, the TDS content is ≤5000 mg / L, the ammonia nitrogen content is ≤350 mg / L, and the nitrate ion content is ≤400 mg / L.

[0014] Preferably, the dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour are 30-40 mg / L; the dosage of the microbial growth promoter and the solid-liquid ratio of the wastewater treated per hour are 4-10 mg / L; Preferably, the salt-tolerant bacterial agent is selected from one or more of Bacillus licheniformis, Bacillus subtilis, Bacillus coagulans and Bacillus pasteurianus.

[0015] Preferably, the salt-tolerant bacterial agent is composed of a mixture of Bacillus licheniformis and Bacillus coagulans in a ratio of 1-3:0.2-0.8 of live bacteria count; the live bacteria count of the salt-tolerant bacterial agent is ≥ 6 billion / g.

[0016] Furthermore, the salt-tolerant bacterial agent is composed of a mixture of Bacillus licheniformis and Bacillus coagulans with a live bacteria count ratio of 1.5-2.5:0.4-0.6; the live bacteria count of the salt-tolerant bacterial agent is ≥6 billion / g.

[0017] Preferably, the calcium salt is selected from one or more of calcium acetate, calcium propionate, calcium chloride, calcium nitrate, calcium sulfate, superphosphate, calcium citrate, calcium gluconate, and amino acid calcium.

[0018] Preferably, the inorganic phosphoric acid substance is selected from one or more of sodium tripolyphosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium pyrophosphate, and sodium hexametaphosphate.

[0019] Preferably, the organic phosphonic acid substance is selected from one or more of hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, ethylenediaminetetramethylenephosphonic acid, 2-hydroxyphosphonoacetic acid, polyaminopolyether methylenephosphonic acid, and diethylenetriaminepenta(methylenephosphonic acid).

[0020] Preferably, the microbial growth promoter specifically comprises the following components in parts by weight: 16-19 parts by weight of superphosphate, 5-7 parts by weight of spermidine, 5-7 parts by weight of sodium fatty acid methyl ester sulfonate, 2-3 parts by weight of sodium pyrophosphate, and 0.2-0.4 parts by weight of ethylenediaminetetramethylenephosphonic acid. In summary, the technical solution of this application has the following effects: By using the treatment method provided in this application, the salt-containing wastewater from the coal chemical industry is subjected to pretreatment, advanced oxidation treatment, and biochemical treatment steps in sequence, and the types and amounts of salt-tolerant bacteria agents and microbial growth promoters in the biochemical treatment process are controlled. The impurity contents such as COD, ammonia nitrogen, TDS, nitrate ions, etc. in the high-salt wastewater from the coal chemical industry can be effectively removed, achieving excellent wastewater treatment effects. DETAILED DESCRIPTION

[0021] The present application is further described in detail below in conjunction with examples, comparative examples and performance testing experiments. These examples should not be construed as limiting the scope of protection claimed in the present application. Example

[0022] Examples 1-6 Examples 1-6 respectively provide a method for treating salt-containing wastewater from coal chemical industry.

[0023] The difference between the above embodiments is that the types of salt-tolerant bacteria agents in the biochemical treatment step are different, as shown below.

[0024] In Example 1: Bacillus licheniformis and Bacillus coagulans were taken at a live bacterial count ratio of 2:0.5, and then placed in the same LB medium for culture for 36 hours at a fermentation temperature of 35-37°C. After the culture was completed, a seed solution was obtained; then the seed solution was inoculated into a 100L culture tank containing LB medium at an inoculum amount of 10% for fermentation for 36 hours at a fermentation temperature of 32-37°C, until the bacterial count density reached more than 100 under microscopic examination of the bacteria, and the culture was terminated when the spore production rate reached more than 99%, and a salt-tolerant bacterial agent with a live bacterial count of approximately 6.5 billion / g was obtained.

[0025] In Example 2: Bacillus licheniformis and Bacillus coagulans were taken at a live bacterial count ratio of 1:0.8, and then placed in the same LB medium for culture for 36 hours at a fermentation temperature of 35-37°C. After the culture was completed, a seed solution was obtained; the seed solution was then inoculated into a 100L culture tank containing LB medium at an inoculum size of 10% for fermentation for 36 hours at a fermentation temperature of 32-37°C, until the bacterial count density reached more than 100 under microscopic examination of the bacteria, and the culture was terminated when the spore production rate reached more than 99%, and a salt-tolerant bacterial agent with a live bacterial count of approximately 6.5 billion / g was obtained.

[0026] In Example 3: Bacillus licheniformis and Bacillus coagulans were taken at a live bacterial count ratio of 3:0.2, and then placed in the same LB medium for culture for 36 hours at a fermentation temperature of 35-37°C. After the culture was completed, a seed solution was obtained; the seed solution was then inoculated into a 100L culture tank containing LB medium at an inoculum size of 10% for fermentation for 36 hours at a fermentation temperature of 32-37°C, until the bacterial count density reached more than 100 under microscopic examination of the bacteria, and the culture was terminated when the spore production rate reached more than 99%, and a salt-tolerant bacterial agent with a live bacterial count of approximately 6.5 billion / g was obtained.

[0027] In Example 4: Bacillus licheniformis and Bacillus coagulans were taken at a live bacterial count ratio of 0.5:2, and then placed in the same LB medium for culture for 36 hours at a fermentation temperature of 35-37°C. After the culture was completed, a seed solution was obtained; the seed solution was then inoculated into a 100L culture tank containing LB medium at an inoculum size of 10% for fermentation for 36 hours at a fermentation temperature of 32-37°C, until the bacterial count density reached more than 100 under microscopic examination of the bacteria, and the culture was terminated when the spore production rate reached more than 99%, and a salt-tolerant bacterial agent with a live bacterial count of approximately 6.5 billion / g was obtained.

[0028] In Example 5: Bacillus licheniformis and Bacillus subtilis were taken at a live bacterial count ratio of 2:0.5, and then placed in the same LB medium for culture for 36 hours at a fermentation temperature of 35-37°C. After the culture was completed, a seed solution was obtained; the seed solution was then inoculated into a 100L culture tank containing LB medium at an inoculum size of 10% for fermentation for 36 hours at a fermentation temperature of 32-37°C until the bacterial count density reached more than 100 under microscopic examination of the bacteria. The culture was terminated when the spore production rate reached more than 99%, and a salt-tolerant bacterial agent with a live bacterial count of approximately 6.5 billion / g was obtained.

[0029] In Example 6: Bacillus pasteurianus and Bacillus subtilis were taken at a live bacterial count ratio of 2:0.5, and then placed in the same LB medium for culture for 36 hours at a fermentation temperature of 35-37°C. After the culture was completed, a seed solution was obtained; then the seed solution was inoculated into a 100L culture tank containing LB medium at an inoculum amount of 10% for fermentation for 36 hours at a fermentation temperature of 32-37°C until the bacterial count density reached more than 100 under microscopic examination of the bacteria. When the spore production rate reached more than 99%, the culture was terminated to obtain a salt-tolerant bacterial agent with a live bacterial count of approximately 6.5 billion / g.

[0030] The method for treating salt-containing wastewater from coal chemical industry in the above embodiment specifically comprises the following steps in sequence: The average concentrations of pollutants in coal chemical high-salt wastewater are: COD is 5721 mg / L, total hardness (calculated as CaCO3) is 1235 mg / L, total alkalinity (calculated as CaCO3) is 815 mg / L, TDS is 6598 mg / L, ammonia nitrogen content is 398 mg / L, and pH value is 8.

[0031] (1) Pretreatment: Coal chemical high-salt wastewater enters the high-density clarification tank reaction zone, calcium hydroxide is added to adjust the pH value to 10.5-11.0, sodium carbonate with a final concentration of 2.0g / L, PFS with a final concentration of 10mg / L, and PAM with a final concentration of 1mg / L are added for coagulation. After sufficient coagulation, it enters the clarification zone for precipitation, and finally hydrochloric acid is added at the outlet of the clarification tank to adjust the pH to about 7. The effluent is filtered to remove suspended matter and colloidal particles in the water.

[0032] (2) Advanced oxidation treatment: The pretreated concentrated water enters the Fenton reaction tank, and the pH value is adjusted to 2.8-3.2. Then, hydrogen peroxide with a final concentration of 160 mg / L, ferrous salt of 10 mg / L, and spermine of 0.4 mg / L are added in sequence, and the reaction time is 4 h. After Fenton oxidation, the COD content in the water is 1058 mg / L, the TDS content is 4857 mg / L, the ammonia nitrogen content is 302 mg / L, and the nitrate ion content is 367 mg / L.

[0033] (3) Biochemical treatment: The effluent from the advanced oxidation treatment enters the biochemical unit. Before the water enters the biofilter of the biochemical unit, activated sludge is inoculated at a sludge concentration of 4000 mg / L for startup; the conditions are: temperature 27°C, pH 7.5, and dissolved oxygen concentration 1.0 mg / L. In the filter, a salt-tolerant bacteria agent is added at a rate of 35 mg / L of the volume of wastewater treated per hour, and a microbial growth promoter is added at a rate of 7 mg / L of the volume of wastewater treated per hour to remove COD and nitrate. The total hydraulic retention time of the biochemical treatment is 96 hours. The microbial growth promoter is composed of the following components in parts by weight: 17 parts by weight of superphosphate, 6 parts by weight of spermidine, 6 parts by weight of sodium fatty acid methyl ester sulfonate, 2.5 parts by weight of sodium pyrophosphate, and 0.3 parts by weight of ethylenediaminetetramethylenephosphonic acid.

[0034] (4) Post-treatment: The effluent from the biochemical treatment enters the high-density clarification tank, and sodium hydroxide is added to the reaction zone of the clarification tank to maintain the pH value at about 11.5. Sodium carbonate with a final concentration of 2.0g / L, PFS with a final concentration of 40mg / L, and PAM with a final concentration of 4mg / L are added. After sufficient coagulation, it enters the clarification zone for precipitation. Finally, hydrochloric acid is added at the outlet of the clarification tank to adjust the pH to about 7. Then, the suspended matter and colloidal particles in the water are removed through the filter tank, and the turbidity of the wastewater is controlled to ≤3NTU, and it enters the ultrafiltration device with an operating pressure of 0.05MPa. After ultrafiltration treatment, the wastewater indicators are finally made to have hardness ≤50mg / L, COD ≤65mg / L, and turbidity ≤1NTU.

[0035] Embodiment 7-11 Examples 7-11 respectively provide a method for treating salt-containing wastewater from coal chemical industry.

[0036] The difference between the above embodiment and embodiment 1 is that the types of microbial growth promoters are different, as shown below.

[0037] In Example 7: the microbial growth promoter is composed of the following components in parts by weight: 17 parts by weight of calcium propionate, 6 parts by weight of spermidine, 6 parts by weight of sodium fatty acid methyl ester sulfonate, 2.5 parts by weight of sodium hexametaphosphate, and 0.3 parts by weight of diethylenetriamine penta (methylene phosphonic acid).

[0038] In Example 8: the microbial growth promoter is composed of the following components in parts by weight: 17 parts by weight of calcium gluconate, 6 parts by weight of spermidine, 6 parts by weight of sodium fatty acid methyl ester sulfonate, 2.5 parts by weight of sodium hexametaphosphate, and 0.3 parts by weight of aminotrimethylenephosphonic acid.

[0039] In Example 9: the microbial growth promoter is composed of the following components in parts by weight: 15 parts by weight of superphosphate, 8 parts by weight of spermidine, 4 parts by weight of sodium fatty acid methyl ester sulfonate, 1 part by weight of sodium pyrophosphate, and 0.5 parts by weight of ethylenediaminetetramethylenephosphonic acid.

[0040] In Example 10: the microbial growth promoter is composed of the following components in parts by weight: 16 parts by weight of superphosphate, 7 parts by weight of spermidine, 5 parts by weight of sodium fatty acid methyl ester sulfonate, 2 parts by weight of sodium pyrophosphate, and 0.4 parts by weight of ethylenediaminetetramethylenephosphonic acid.

[0041] In Example 11: the microbial growth promoter is composed of the following components in parts by weight: 19 parts by weight of superphosphate, 5 parts by weight of spermidine, 7 parts by weight of sodium fatty acid methyl ester sulfonate, 3 parts by weight of sodium pyrophosphate, and 0.2 parts by weight of ethylenediaminetetramethylenephosphonic acid.

[0042] The other process parameters in the above embodiment are the same as those in embodiment 1.

[0043] Examples 12-15 Examples 12-15 respectively provide a method for treating salt-containing wastewater from coal chemical industry.

[0044] The difference between the above embodiment and embodiment 1 is that the dosage of the salt-tolerant bacteria agent and the microbial growth promoter is different, as shown below.

[0045] In Example 12: the dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour was 20 mg / L; the dosage of the microbial growth promoter and the solid-liquid ratio of the wastewater treated per hour was 12 mg / L.

[0046] In Example 13: the dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour was 50 mg / L; the dosage of the microbial growth promoter and the solid-liquid ratio of the wastewater treated per hour was 2 mg / L.

[0047] In Example 14: the dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour was 30 mg / L; the dosage of the microbial growth promoter and the solid-liquid ratio of the wastewater treated per hour was 4 mg / L.

[0048] In Example 15: the dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour was 40 mg / L; the dosage of the microbial growth promoter and the solid-liquid ratio of the wastewater treated per hour was 10 mg / L.

[0049] The other process parameters in the above embodiment are the same as those in embodiment 1.

[0050] Comparative Example Comparative Examples 1-3 Comparative Examples 1-3 respectively provide a method for treating salt-containing wastewater from coal chemical industry.

[0051] The differences between the above comparative example and Example 1 are specifically as follows.

[0052] In Comparative Example 1: the microbial growth promoter is composed of the following components in parts by weight: 17 parts by weight of calcium propionate, 2.5 parts by weight of sodium hexametaphosphate, and 0.3 parts by weight of diethylenetriamine penta(methylenephosphonic acid).

[0053] In Comparative Example 2: the microbial growth promoter is composed of the following components in parts by weight: 30 parts by weight of calcium propionate, 2 parts by weight of spermidine, 10 parts by weight of sodium fatty acid methyl ester sulfonate, 0.5 parts by weight of sodium hexametaphosphate, and 1 part by weight of diethylenetriamine penta(methylenephosphonic acid).

[0054] In Comparative Example 3: the dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour was 60 mg / L; the dosage of the microbial growth promoter and the solid-liquid ratio of the wastewater treated per hour was 1 mg / L.

[0055] The other process parameters in the above comparative example are the same as those in Example 1.

[0056] Performance testing The water quality of the biochemical unit inlet (i.e. the water quality of the advanced oxidation treatment effluent) is: COD content is 1058 mg / L, TDS content is 4857 mg / L, ammonia nitrogen content is 302 mg / L, and nitrate ion content is 367 mg / L.

[0057] The effluent from step (4) in the embodiment and the comparative example after being treated by the biological filter of the biochemical unit was specifically tested to evaluate the wastewater treatment status.

[0058] Test results: as shown in Table 1 Table 1 Wastewater treatment test results in the examples and comparative examples Combined with Table 1, by comparing the test results of the embodiments and the comparative examples, it can be seen that by using the treatment method provided by the present application, the coal chemical saline wastewater is subjected to pretreatment, advanced oxidation treatment, and biochemical treatment steps in sequence, and the type and amount of the salt-tolerant bacteria agent and the microbial growth promoter in the biochemical treatment process are controlled, which can effectively remove the impurity content of COD, ammonia nitrogen, TDS, nitrate ions, etc. in the high-salt wastewater of the coal chemical industry, thereby achieving excellent wastewater treatment effect.

[0059] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for treating salt-containing wastewater from coal chemical industry, characterized in that: Specifically, the following steps are carried out in sequence: pretreatment, advanced oxidation treatment, biochemical treatment, and post-treatment; The specific steps of the advanced oxidation treatment are: the pretreated concentrated water enters the Fenton reaction tank, the pH value is adjusted to 2.8-3.2, and then hydrogen peroxide with a final concentration of 120-180 mg / L, 5-15 mg / L of ferrous salt, and 0.2-0.6 mg / L of spermine are added in sequence, and the reaction time is 3-5 hours; The specific steps of the biochemical treatment are: the effluent from the advanced oxidation treatment enters the biochemical unit, and a salt-tolerant bacteria agent and a microbial growth promoter are added, and the treatment time is 72-120 hours; The dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour are 20-50 mg / L; The dosage of the microbial growth promoter is 2-12 mg / L to the solid-liquid ratio of the wastewater treated per hour; The microbial growth promoter specifically comprises the following components in parts by weight: 15-20 parts by weight of calcium salt, 4-8 parts by weight of spermidine, 4-8 parts by weight of sodium fatty acid methyl ester sulfonate, 1-4 parts by weight of inorganic phosphoric acid substances, and 0.1-0.5 parts by weight of organic phosphonic acid substances.

2. The method for treating salt-containing wastewater from coal chemical industry according to claim 1, characterized in that: The specific steps of the pretreatment are: the coal chemical saline wastewater enters the reaction zone of the high-density clarification tank, calcium hydroxide is added to adjust the pH value to 10.5-11.0, and then sodium carbonate with a final concentration of 1.8-2.2g / L, PFS with a final concentration of 8-12mg / L for coagulation, and PAM with a final concentration of 0.7-1.5mg / L for coagulation aid. After sufficient coagulation, it enters the clarification zone for precipitation, and finally hydrochloric acid is added at the outlet of the clarification tank to adjust the pH to about 7; the water passes through the filter tank to remove suspended matter and colloidal particles in the water.

3. The method for treating salt-containing wastewater from coal chemical industry according to claim 1, characterized in that: After the advanced oxidation treatment, the COD content in the water is ≤1100 mg / L, the TDS content is ≤5000 mg / L, the ammonia nitrogen content is ≤350 mg / L, and the nitrate ion content is ≤400 mg / L.

4. The method for treating salt-containing wastewater from coal chemical industry according to claim 1, characterized in that: The dosage of the salt-tolerant bacteria agent and the solid-liquid ratio of the wastewater treated per hour are 30-40 mg / L; the dosage of the microbial growth promoter and the solid-liquid ratio of the wastewater treated per hour are 4-10 mg / L.

5. The method for treating salt-containing wastewater from coal chemical industry according to claim 1, characterized in that: The salt-tolerant bacterial agent is selected from one or more of Bacillus licheniformis, Bacillus subtilis, Bacillus coagulans and Bacillus pasteurianus.

6. The method for treating salt-containing wastewater from coal chemical industry according to claim 5, characterized in that: The salt-tolerant bacterial agent is composed of a mixture of Bacillus licheniformis and Bacillus coagulans in a ratio of 1-3:0.2-0.8 of live bacteria count; the live bacteria count of the salt-tolerant bacterial agent is ≥6 billion / g.

7. The method for treating salt-containing wastewater from coal chemical industry according to claim 1, characterized in that: The calcium salt is selected from one or more of calcium acetate, calcium propionate, calcium chloride, calcium nitrate, calcium sulfate, superphosphate, calcium citrate, calcium gluconate, and amino acid calcium.

8. The method for treating salt-containing wastewater from coal chemical industry according to claim 1, characterized in that: The inorganic phosphoric acid substance is selected from one or more of sodium tripolyphosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium pyrophosphate, and sodium hexametaphosphate.

9. The method for treating salt-containing wastewater from coal chemical industry according to claim 1, characterized in that: The organic phosphonic acid substance is selected from one or more of hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, ethylenediaminetetramethylenephosphonic acid, 2-hydroxyphosphonoacetic acid, polyaminopolyether methylenephosphonic acid, and diethylenetriaminepenta(methylenephosphonic acid).

10. The method for treating salt-containing wastewater from coal chemical industry according to claim 1, characterized in that: The microbial growth promoter specifically comprises the following components in parts by weight: 16-19 parts by weight of superphosphate, 5-7 parts by weight of spermidine, 5-7 parts by weight of sodium fatty acid methyl ester sulfonate, 2-3 parts by weight of sodium pyrophosphate, and 0.2-0.4 parts by weight of ethylenediaminetetramethylenephosphonic acid.

Images