A method for treating sewage containing difficult-to-degrade substances to achieve deep standard

Abstract

The present invention discloses a method for achieving deep treatment of wastewater containing refractory substances. The method comprises: (1) filling activated carbon at 30% to 70% of the effective volume of the reactor; (2) subjecting activated sludge used to treat refractory organic pollutants to cell wall destruction, releasing intracellular substances and removing impurities, retaining the liquid above and adding it to step (1), aerating the sludge, and controlling the dissolved oxygen to above 5 mg / L; (3) adding an oil-resistant immobilized carrier to step (2), and simultaneously inoculating a salt-tolerant bacterial agent capable of treating organic pollutants and nitrogen-containing pollutants, aerating the sludge continuously for 5 to 7 days under conditions of dissolved oxygen of 2 to 6 mg / L and a pH of 7 to 9, and then treating the wastewater according to a set hydraulic retention time. The method of the present invention utilizes activated sludge that has undergone cell wall destruction, activated carbon, and an oil-resistant immobilized carrier to cooperate with each other, thereby achieving dynamic biological regeneration of the activated carbon, extending the service life of the activated carbon, and achieving simultaneous deep removal of organic pollutants and nitrogen-containing pollutants.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular relates to a method for deeply treating sewage containing difficult-to-degrade substances to meet standards. Background Art

[0002] Refinery wastewater typically undergoes pre-treatment, such as oil separation and flotation, before being treated in a downstream biochemical unit to meet standards before being directly discharged or reused. However, with the deterioration of crude oil quality and the addition of various chemicals during crude oil extraction, wastewater generated during the refining process has become increasingly difficult to treat due to the increased concentration and variety of pollutants. This is particularly true with the tightening of emission standards. National standards GB31570-2015 and GB31571-2015 stipulate special emission limits for COD concentrations of less than 50 mg / L and total nitrogen concentrations of less than 30 mg / L in discharged wastewater, with some local standards being even stricter. While most companies' existing facilities can achieve these standards, the effluent from secondary or tertiary biochemical units often contains some large, recalcitrant substances. With the increase in water recovery and wastewater reuse rates, salinity in wastewater has increased, creating challenges in selecting advanced wastewater treatment technologies.

[0003] Existing industrial wastewater deep treatment technologies mainly include membrane treatment technology, ozone oxidation treatment technology, and activated carbon deep treatment technology. Membrane treatment technology has good effluent quality, but it has technical defects such as high operating costs and the inability to properly dispose of concentrated water generated by the system; ozone deep treatment technology has a good treatment effect on the main pollutants in the tail water, but it has technical defects such as complex process flow and the risk of secondary by-product pollution. The ozone + BAF deep treatment process commonly used by existing enterprises still cannot achieve the expected treatment effect. Activated carbon deep treatment technology uses the physical adsorption capacity of activated carbon in combination with microorganisms attached to its surface for combined treatment. It has good decolorization and deodorization effects and has a significant removal effect on the main pollutants in the tail water. However, it still has technical defects such as low efficiency of activated carbon use and excessive consumption.

[0004] Zhang Guangyu (Master's thesis) "Research on Enhanced Treatment Technology for SBR Process Wastewater Treatment Plants Against Petroleum Pollutant Shocks" investigated the feasibility of combining powdered activated carbon (PAC) and the SBR process to enhance the removal of oil pollution. The results showed that a PAC dosage of 0.2g / L could effectively protect the SBR process from a 100mg / L concentration of oil pollution; and a PAC dosage of 0.5g / L could effectively protect the SBR process from a 200mg / L concentration of oil pollution. This method synergistically enhances the activity of microorganisms by combining the adsorption and catalytic effects of activated carbon, promoting their metabolic activity, thereby extending the activated carbon's working cycle and improving its adsorption conditions, achieving the goal of removing refractory organic matter. The activated carbon in this method is continuously discharged with the sludge, which adds additional operating costs.

[0005] CN201910665816.9 discloses a method and equipment for deep treatment of sewage based on activated carbon technology, the steps of which are as follows: 1) injecting a water sample of wastewater to be treated into a culture device, and then adding powdered activated carbon and culture solution; 2) adding the cultured biological activated carbon to a biological activated carbon water treatment device; 3) introducing the sewage to be treated into the biological activated carbon water treatment device, performing a first aeration treatment, and obtaining biodegradable water; 4) introducing the biodegradable water into a multifunctional sewage treatment device, adding a sewage treatment agent, and performing a second aeration treatment; 5) filtering the multifunctional treated water through an ultrafiltration membrane to obtain a dischargeable water that meets the emission standards. The method first involves adding powdered activated carbon and a culture solution for aeration culture to obtain a biological activated carbon with microorganisms parasitic on the surface; then aerating the cultured biological activated carbon to treat the wastewater to be treated, and the microorganisms on the biological activated carbon will consume part of the biodegradable organic matter in the wastewater and convert it into carbon dioxide for degradation and elimination; adding a sewage treatment agent to obtain the biodegradable water, filtering it through an ultrafiltration membrane, and achieving a dischargeable water that meets the emission standards. This method separates the loading of microorganisms on the surface of powdered activated carbon and the biodegradation treatment of sewage. Although it achieves standard treatment of tail water, it still requires the addition of new carbon and involves high-temperature regeneration. It cannot achieve dynamic regeneration of activated carbon and still increases operating costs.

[0006] CN201610132948.1 discloses TritonX~100 enhanced biochar immobilized microbial material and its preparation method and application. Trion X~100 is used to enhance the co-adsorption of pollutants and degradation bacteria Pseudomonas aeruginosa by biochar, thereby improving the overall removal efficiency of biochar immobilized microbial materials for organic pollutants in wastewater. The Triton X~100 enhanced biochar immobilized microbial material prepared by this method has a good adsorption and removal effect on difficult-to-degrade organic matter in wastewater, and has a significantly improved removal efficiency of organic matter compared to traditional adsorption methods of immobilized microorganisms. The biochar used in this method is obtained by cracking one or more of rice straw, bamboo powder, and rice bran under anoxic conditions at 500°C. The specific surface area of ​​this activated carbon is less than 300m 2 / g, with an average pore size of 4 to 10 nm. It is a mesoporous material and can easily be saturated with adsorption if not handled properly. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention provides a method for achieving high-quality treatment of wastewater containing refractory substances. This method utilizes activated sludge treated with wall-breaking technology, activated carbon, and an oil-resistant immobilized carrier to achieve dynamic biological regeneration of the activated carbon, further extending its lifespan and simultaneously achieving high-quality removal of organic and nitrogen-containing pollutants.

[0008] The first aspect of the present invention provides a method for treating wastewater containing refractory substances to achieve advanced standards, comprising the following steps:

[0009] (1) Filling the reactor with activated carbon at 30% to 70%, preferably 40% to 60%, of its effective volume;

[0010] (2) breaking the cell wall of the activated sludge used to treat refractory organic pollutants to release the substances in the cells, precipitating or filtering to remove impurities, and adding the retained liquid to step (1), and treating with simmering for 12 to 24 hours, and controlling the dissolved oxygen concentration to be above 5 mg / L, preferably 5 to 7 mg / L;

[0011] (3) adding an oil-resistant immobilized carrier to the reaction system of step (2), and simultaneously inoculating a salt-tolerant bacterial agent capable of treating organic pollutants and nitrogen-containing pollutants, and continuously aerating for 5 to 7 days under the conditions of dissolved oxygen of 2 to 6 mg / L, pH of 7 to 9, and temperature of 25 to 40°C, and then treating the sewage according to the set hydraulic retention time.

[0012] In the present invention, backwashing is performed regularly during the treatment process. The backwashing time and frequency depend on the specific biofilm growth conditions, and are generally performed once a week or a month.

[0013] In the present invention, the activated carbon in step (1) is coal-based activated carbon with a particle size of 2 to 8 mm and a specific surface area of ​​600 to 1000 m 2 / g, iodine value 600-1000 mg / g, methylene blue 90-120 mg / g.

[0014] In the present invention, the cell wall breaking treatment in step (2) is well known to those skilled in the art, and can be carried out by at least one of excessive aeration, mechanical stirring, ultrasonic crushing or chemical penetration with the addition of a surfactant.

[0015] In the present invention, in the oil-resistant immobilized carrier of step (3), the metal content in terms of oxides accounts for 1% to 20% of the mass of the modified aerogel, the humic acid accounts for 0.1% to 10% of the mass of the modified aerogel, and the sugar ester-producing microorganisms account for 5% to 50% of the mass of the modified aerogel, preferably 10% to 30%.

[0016] In the present invention, the oil-resistant immobilized carrier is added according to a solid-liquid mass concentration of 20 to 50 mg / L after addition.

[0017] In the present invention, the oil-resistant immobilized carrier is prepared according to the following method: (a) placing the aerogel in an acetic acid solution for reaction, taking it out and washing it to neutrality; (b) dissolving humic acid in a Fe(OH)3 solution, adding the aerogel, reacting at 50-70°C, and washing it to weak alkalinity to obtain a modified aerogel; (c) loading active metals on the modified aerogel to obtain a metal-loaded carrier; (d) adsorbing sugar ester-producing microorganisms on the metal-loaded carrier, and drying after the adsorption is completed to obtain an immobilized carrier.

[0018] In the present invention, the aerogel in step (a) is at least one of carbon aerogel, silicon aerogel, cellulose aerogel, etc., preferably carbon aerogel. It is usually obtained by homemade or commercial purchase, and the specific surface area of ​​the aerogel is 600 to 1100 m 2 / g, porosity is 80% to 98%.

[0019] In the present invention, the concentration of the acetic acid solution in step (a) is 1.0 to 2.0 mol / L. The aerogel is immersed in the acetic acid solution for reaction at a temperature of 30 to 50°C for 1.0 to 2.0 hours. The reaction can be carried out directly or in a water bath, preferably in a water bath at 30 to 50°C. After removal, the aerogel is washed until the pH is neutral, typically 6.5 to 7.5.

[0020] In the present invention, the concentration of the Fe(OH)3 solution in step (b) is 0.5-0.8 mol / L, and the mass ratio of the Fe(OH)3 solution to humic acid is 1:1-3:1.

[0021] In the present invention, in step (b), the aerogel is immersed in a mixture of humic acid and Fe(OH)3 solution and reacted in a water bath at 50-70°C for 3-5 hours. After removal, the aerogel is washed until the pH value is weakly alkaline, generally 7.6-8.0.

[0022] In the present invention, the active metal in step (c) is Cu 2+ 、Fe 2+ Mg 2+ At least one of the following, preferably Fe 2+ The active metal loading can be carried out using conventional impregnation methods in the art, such as equal volume impregnation or excess impregnation. Typically, a soluble salt solution of the active metal is used, wherein the metal ion concentration is 1 to 4 mol / L. For example, the modified aerogel can be impregnated into the active metal solution at 60 to 70°C for 6 to 10 hours.

[0023] In the present invention, step (d) involves immersing the metal-loaded carrier in the fermentation broth of a sugar ester-producing microorganism for adsorption growth of the microorganism, with the volume ratio of the metal-loaded carrier to the fermentation broth being 1:1 to 3. The adsorption growth conditions are: a temperature of 20°C to 38°C, preferably 20°C to 30°C, a pH of 6.0 to 8.5, preferably 6.0 to 7.0, and a reaction time of 12 to 36 hours.

[0024] In the present invention, the sugar ester-producing microorganism in step (d) is a microorganism that ferments and produces at least one sugar ester among rhamnosyl ester, trehalose lipid, sophorolipid and sucrose ester, etc., such as at least one of rhamnosyl ester-producing Pseudomonas aeruginosa and trehalose lipid-producing Pseudomonas aeruginosa. The preparation method of the sugar ester-producing microbial fermentation broth is conventional in the art.

[0025] In the present invention, the drying step (d) is performed at 35-50°C for 24-48 hours to obtain an immobilized carrier. The synthesized oil-resistant immobilized carrier comprises metals (as oxides) accounting for 1% to 20% of the mass of the modified aerogel, humic acid accounting for 0.1% to 10% of the mass of the modified aerogel, and sugar ester-producing microorganisms accounting for 5% to 50% of the mass of the modified aerogel, preferably 10% to 30%. The synthesized immobilized carrier needs to be stored under vacuum before use, and the shelf life is generally 1 to 3 months.

[0026] In the present invention, the salt-tolerant bacterial agent described in step (3) is a liquid bacterial agent or an activated bacterial agent well known to those skilled in the art, and can be a combination of single bacterial strains that have the functions of removing difficult-to-degrade organic pollutants and removing total nitrogen. Preferably, the bacterial agent comprises a combination of Pseudomonas, Bacillus, and Denitrifying Paracoccus. The inoculation amount of the salt-tolerant bacterial agent is inoculated at a ratio of 0.01% to 0.05% of the volume of the salt-tolerant bacterial agent to the effective volume of the sewage treatment device.

[0027] In the present invention, the reactor refers to any reactor with an aeration function, with a supporting layer configured at the bottom. The aeration amount is not determined according to the dissolved oxygen, but is based on whether the activated carbon loaded on the upper layer can flow up and down.

[0028] In the present invention, the sewage can be at least one of the effluent from a secondary biochemical unit, RO concentrated water, circulating water wastewater, etc. Furthermore, the water quality of the sewage is: an ammonia nitrogen concentration of 10 to 20 mg / L, a total nitrogen of 30 to 50 mg / L, a COD concentration of 60 to 150 mg / L, and a B / C ratio of less than 0.3.

[0029] In the present invention, the sewage depth reaching the standard means that after treatment, the effluent ammonia nitrogen concentration is less than 1 mg / L, the total nitrogen concentration is less than 15 mg / L, and the COD concentration is less than 30 mg / L.

[0030] In the present invention, the setting of the hydraulic retention time in step (3) refers to setting the hydraulic retention time to 2 to 6 hours, preferably 3 to 5 hours.

[0031] The second aspect of the present invention provides a device for deep treatment of sewage containing difficult-to-degrade substances to meet the above-mentioned standards. The treatment device mainly includes a sewage treatment system and a monitoring system. The sewage treatment system is filled with activated carbon and oil-resistant immobilized carriers, and is inoculated with activated sludge and salt-tolerant bacteria for sewage treatment; the monitoring system is used to monitor the system effluent. When operating at full load, when the system effluent ammonia nitrogen concentration is less than 5 mg / L, TN concentration is less than 15 mg / L, and COD concentration is less than 30 mg / L, it can enter the double membrane system for further reuse.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention first performs a wall-breaking treatment on the sludge, then adds it to the activated carbon system, and finally adds an oil-resistant immobilized carrier. The three cooperate with each other, so that the activated carbon adsorbs large molecular organic matter, the enzyme decomposes the large molecular organic matter, and the microorganisms degrade the small molecular organic matter. This series of reactions forms a virtuous cycle, thereby realizing the dynamic regeneration of the activated carbon.

[0034] (2) The oil-resistant immobilized carrier used in the present invention easily adsorbs functional microorganisms to form biofilms, reducing the biofilm load on the activated carbon surface, mitigating the risk of internal pore blockage, facilitating the rapid adsorption of macromolecular substances, and improving water effluent quality. The microorganisms on the oil-resistant immobilized carrier slowly release biosurfactants during their growth and metabolism, which further clears the pores on the activated carbon surface and enhances the bioregeneration ability of the activated carbon.

[0035] (3) The present invention uses two carriers to achieve simultaneous deep removal of organic pollutants and nitrogen-containing pollutants. The two carriers work together to greatly improve the efficiency of activated carbon use and sewage treatment effects, further extending the service life of activated carbon and making the effluent water quality more stable.

[0036] (4) When preparing an oil-resistant immobilized carrier, after loading the active metal onto the modified aerogel, the microorganisms that produce sugar esters are grown by adsorption, thereby making the synthesized immobilized carrier have long-lasting oil resistance during use. In particular, it can prevent the loss of active metals, without affecting the sewage treatment effect and the long-term stability of the system operation. Using humic acid to modify the aerogel and then loading the active metal onto the modified aerogel to synthesize the pre-adsorption carrier helps to enhance the adsorption of sugar ester-producing microorganisms. Through the synergistic effect between the three, the various substances are tightly bound, have strong binding force, and will not be lost during long-term use. DETAILED DESCRIPTION

[0037] The following examples further illustrate the method and effects of the present invention. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples.

[0038] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, can all be purchased from biochemical reagent stores.

[0039] In the embodiments of the present invention, the COD concentration is determined by GB11914-89 "Water quality - Determination of chemical oxygen demand - Dichromate method"; the ammonia nitrogen concentration is determined by GB7478-87 "Water quality - Determination of ammonium - Distillation and titration method"; the total nitrogen concentration is determined by GB11894-89 "Water quality - Determination of total nitrogen - Ultraviolet spectrophotometry"; the metal ions are determined by inductively coupled plasma mass spectrometry; and the effluent suspended solids are determined by GB11901-89 "Water quality - Determination of suspended solids - Gravimetric method".

[0040] Example 1

[0041] The preparation method of the oil-resistant immobilized carrier used in this embodiment is as follows:

[0042] (1) Carbon aerogel (specific surface area of ​​800m 2 / g, porosity of 80%) were immersed in 1.5 mol / L acetic acid solution for water bath reaction at 40°C and shaken for 1.5 h. After being taken out, the carbon aerogel was washed with deionized water to pH 7.0 to obtain the pretreated carbon aerogel.

[0043] (2) Humic acid was dissolved in 0.6 mol / L Fe(OH)3 solution at a mass ratio of 2:1, and then the pretreated carbon aerogel was added. The mixture was shaken in a water bath at 60°C for 4 h, taken out and washed with deionized water to pH 8.0 to obtain modified aerogel.

[0044] (3) A ferrous sulfate solution with an iron ion concentration of 1 mol / L was prepared, the modified aerogel was added, and the solution was immersed at 65°C with stirring for 8 h to obtain a carrier loaded with active metals.

[0045] (4) The active metal-loaded carrier was mixed with a fermentation broth of rhamnosyl-producing Pseudomonas aeruginosa at a volume ratio of 1:1. Adsorption growth was allowed to proceed at 30°C and pH 6.5 for 12 h, yielding a carrier adsorbing Pseudomonas aeruginosa. The microorganism-adsorbed carrier was removed and dried at 45°C for 24 h, ultimately yielding immobilized carrier A.

[0046] The rhamnosylester-producing Pseudomonas aeruginosa used in this example was obtained according to the method described in the literature "Screening of Biosurfactant-Producing Bacteria" (Pan Bingfeng, Acta Microbiologica Sinica, June 1996, 39(3)). After enrichment culture and screening using blood agar plates, a strain with stable genetic traits and rhamnosylester production was obtained through shake flask fermentation and rescreening. The strain was identified as Pseudomonas aeruginosa using 16S rRNA and other methods.

[0047] The preparation method of Pseudomonas aeruginosa fermentation broth comprises: picking colonies from a slant and inoculating them onto LB medium, culturing at 37°C, 200 rpm, and culturing for 24 hours to obtain a seed solution; then inoculating 5% of the seed solution onto a fermentation medium at pH 6.5, 35°C, 200 rpm, and culturing for 7 days to obtain a fermentation broth. The fermentation medium comprises (by mass fraction): 5.0% glucose, 0.5% yeast extract, 0.02% each of KH2PO4, MgSO4, FeSO4·7H2O, and CaCl·2H2O.

[0048] The effective volume is 1m 3 The cylindrical aeration reactor was used to treat sewage that failed to meet the treatment standards of a biochemical unit. The specific water quality was as follows: ammonia nitrogen concentration of 15-20 mg / L, total nitrogen of 30-50 mg / L, COD concentration of 60-150 mg / L, and B / C ratio of less than 0.3. First, pebbles of different particle sizes were loaded into the reactor as a support layer. Then, coal-based activated carbon with a particle size of 2-8 mm (specific surface area of ​​900 m2) was added to fill 50% of the effective volume of the reactor. 2 / g, iodine value 900mg / g, methylene blue 90mg / g. ).

[0049] Take 200L of activated sludge (MLSS is 10g / L) for treating difficult-to-degrade organic pollutants, stir it mechanically for 4h, and then filter to remove impurities. The liquid is added to the above-mentioned reactor loaded with activated carbon and the wastewater to be treated is added. It is simmered and exposed for 24h under a dissolved oxygen concentration of 6mg / L. Then, the oil-resistant immobilized carrier A prepared by the present invention is added to the reactor according to a solid-liquid mass concentration of 40mg / L after addition. At the same time, a salt-tolerant bacterial agent capable of treating organic pollutants and nitrogen-containing pollutants is inoculated at a ratio of 0.05% of the volume of the salt-tolerant bacterial agent to the effective volume of the sewage treatment device. (The bacterial agent 1 prepared in Example 1 of CN201611072924.8 is used) # ) was treated with continuous aeration for five days at a dissolved oxygen level of 4 mg / L, a pH of 7.5-7.8, and a temperature of 28-30°C. The wastewater was then treated with a hydraulic retention time of 4 hours. The reactor was backwashed once a month during the treatment process.

[0050] The reactor has been in operation for 6 months with stable treatment effects. The ammonia nitrogen concentration in the system effluent is less than 0.50 mg / L, the TN concentration is less than 10.2 mg / L, and the COD concentration is less than 25.8 mg / L, achieving deep standard treatment.

[0051] Example 2

[0052] The preparation method of the oil-resistant immobilized carrier used in this embodiment is as follows:

[0053] (1) Carbon aerogel (specific surface area of ​​800m 2 / g, porosity of 80%) were immersed in 1 mol / L acetic acid solution for water bath reaction at 30°C and shaken for 1 hour. The obtained carbon aerogels were taken out and washed with deionized water to pH 6.5 to obtain pretreated carbon aerogels.

[0054] (2) Humic acid was added to 0.5 mol / LFe(OH)3 solution at a mass ratio of 1:1 between Fe(OH)3 solution and humic acid, and then the pretreated carbon aerogel was added. The mixture was shaken in a water bath at 50°C for 3 h, and then washed with deionized water to pH 7.6 to obtain the modified aerogel.

[0055] (3) A ferrous sulfate solution with an iron ion concentration of 2 mol / L was prepared, the modified aerogel was added to the solution, and immersed at 60° C. under stirring conditions for 6 h to obtain a loaded metal carrier.

[0056] (4) The metal-loaded carrier was mixed with a fermentation broth of trehalose lipid-producing Pseudomonas aeruginosa at a volume ratio of 1:3. The carrier was allowed to grow at 25°C and pH 7.0 for 24 hours to obtain a carrier with adsorbed microorganisms. The carrier with adsorbed microorganisms was removed and dried at 35°C for 48 hours to obtain immobilized carrier B.

[0057] The trehalose ester-producing Pseudomonas aeruginosa used in this example was obtained according to the method described in the literature "Screening of Biosurfactant-Producing Bacteria" (Pan Bingfeng, Acta Microbiologica Sinica, June 1996, 39(3)). After enrichment culture and screening using blood agar plates, a strain with stable genetic traits and trehalose ester production was obtained through shake flask fermentation and rescreening. The strain was identified as Pseudomonas aeruginosa using 16S rRNA and other methods.

[0058] The preparation method for Pseudomonas aeruginosa fermentation broth comprises: picking colonies from a slant and inoculating them onto LB medium, culturing at 37°C, 200 rpm, and culturing for 24 hours to obtain a seed solution; then, inoculating 5% of the seed solution onto a fermentation medium at pH 6.8, culturing at 37°C, 200 rpm, and culturing for 7 days to obtain a fermentation broth. The fermentation medium comprises (by mass fraction): 2.0% glucose, 0.5% yeast extract, 1.0% peptone, and 0.02% each of KH2PO4, MgSO4, FeSO4·7H2O, and CaCl·2H2O.

[0059] The effective volume is 1m 3 The cylindrical aeration reactor was used to treat sewage that failed to meet the treatment standards of a biochemical unit. The specific water quality was as follows: ammonia nitrogen concentration of 15-20 mg / L, total nitrogen of 30-50 mg / L, COD concentration of 60-150 mg / L, and B / C ratio of less than 0.3. First, pebbles of different particle sizes were loaded into the reactor as a support layer. Then, coal-based activated carbon with a particle size of 2-8 mm (specific surface area of ​​900 m2) was added to fill 50% of the effective volume of the reactor. 2 / g, iodine value 900mg / g, methylene blue 90mg / g. ).

[0060] 200L of activated sludge (MLSS of 10g / L) for treating difficult-to-degrade organic pollutants was taken and mechanically stirred for 4h, and then filtered to remove impurities. The liquid was added to the above-mentioned reactor loaded with activated carbon and the wastewater to be treated was added. The dissolved oxygen concentration was 6mg / L and then simmered for 24h. Then, the oil-resistant immobilized carrier B prepared by the present invention was added to the reactor according to the solid-liquid mass concentration of 40mg / L after addition. At the same time, the salt-tolerant bacterial agent capable of treating organic pollutants and nitrogen-containing pollutants was inoculated at a ratio of 0.03% of the volume of the salt-tolerant bacterial agent to the effective volume of the sewage treatment device. (The bacterial agent 1 prepared in Example 1 of CN201611072924.8 was used) # ) was treated with continuous aeration for six days at a dissolved oxygen concentration of 3 mg / L, a pH of 7.5-7.8, and a temperature of 30-32°C. The wastewater was then treated with a hydraulic retention time of 5 hours. The reactor was backwashed once a month during the treatment process.

[0061] The reactor has been in operation for 6 months with stable treatment effects. The ammonia nitrogen concentration in the system effluent is less than 0.90 mg / L, the TN concentration is less than 14.3 mg / L, and the COD concentration is less than 27.7 mg / L, achieving deep standard treatment.

[0062] Example 3

[0063] The preparation method of the oil-resistant immobilized carrier is the same as that in Example 1.

[0064] The effective volume is 1m 3The cylindrical aeration reactor was used to treat sewage that failed to meet the treatment standards of a biochemical unit. The specific water quality was as follows: ammonia nitrogen concentration of 15-20 mg / L, total nitrogen of 30-50 mg / L, COD concentration of 60-150 mg / L, and B / C ratio of less than 0.3. First, pebbles of different particle sizes were loaded into the reactor as a support layer. Then, coal-based activated carbon with a particle size of 2-8 mm (specific surface area of ​​900 m2) was added to fill 50% of the effective volume of the reactor. 2 / g, iodine value 900mg / g, methylene blue 90mg / g. ).

[0065] Take 200L of activated sludge (MLSS is 10g / L) for treating difficult-to-degrade organic pollutants, stir it mechanically for 4h, and then filter to remove impurities. The liquid is added to the above-mentioned reactor loaded with activated carbon and the wastewater to be treated is added. It is simmered and exposed for 12h under a dissolved oxygen concentration of 6mg / L. Then, the oil-resistant immobilized carrier A prepared by the present invention is added to the reactor according to a solid-liquid mass concentration of 40mg / L after addition. At the same time, a salt-tolerant bacterial agent capable of treating organic pollutants and nitrogen-containing pollutants is inoculated at a ratio of 0.01% of the volume of the salt-tolerant bacterial agent to the effective volume of the sewage treatment device. (The bacterial agent 1 prepared in Example 1 of CN201611072924.8 is used) # ) was treated with continuous aeration for seven days at a dissolved oxygen concentration of 3 mg / L, a pH of 7.6-7.8, and a temperature of 30-32°C. The wastewater was then treated with a hydraulic retention time of 3.5 hours. The reactor was backwashed once a month during the treatment process.

[0066] The reactor has been in operation for 6 months with stable treatment effects. When the ammonia nitrogen concentration in the system effluent is less than 0.82 mg / L, the TN concentration is less than 14.6 mg / L, and the COD concentration is less than 28.1 mg / L, deep treatment has been achieved.

[0067] Example 4

[0068] The preparation method of the oil-resistant immobilized carrier is the same as that in Example 1.

[0069] The effective volume is 1m 3 The cylindrical aeration reactor was used to treat sewage that failed to meet the treatment standards of a biochemical unit. The specific water quality was as follows: ammonia nitrogen concentration of 15-20 mg / L, total nitrogen of 30-50 mg / L, COD concentration of 60-150 mg / L, and B / C ratio less than 0.3. First, pebbles of different particle sizes were loaded into the reactor as a support layer. Then, coal-based activated carbon with a particle size of 2-8 mm (specific surface area of ​​1000 m2) was added to fill 30% of the reactor's effective volume. 2 / g, iodine value 1000mg / g, methylene blue 90mg / g. ).

[0070] 200L of activated sludge (MLSS of 10g / L) for treating difficult-to-degrade organic pollutants was taken and mechanically stirred for 4h, and then filtered to remove impurities. The liquid was added to the above-mentioned reactor loaded with activated carbon and the wastewater to be treated was added. The dissolved oxygen concentration was 6mg / L and then simmered for 18h. Then, the oil-resistant immobilized carrier A prepared by the present invention was added to the reactor according to a solid-liquid mass concentration of 50mg / L after addition. At the same time, a salt-tolerant bacterial agent capable of treating organic pollutants and nitrogen-containing pollutants was inoculated at a ratio of 0.03% of the volume of the salt-tolerant bacterial agent to the effective volume of the sewage treatment device. (The bacterial agent 1 prepared in Example 1 of CN201611072924.8 was used) # ), with continuous aeration for seven days at 3.5 mg / L dissolved oxygen, a pH of 7.6-7.8, and a temperature of 30-32°C. Wastewater treatment was then performed with a hydraulic retention time of 4 hours. The reactor was backwashed once a month during the treatment process.

[0071] The reactor has been in operation for 6 months with stable treatment effects. When the ammonia nitrogen concentration in the system effluent is less than 0.84 mg / L, the TN concentration is less than 13.8 mg / L, and the COD concentration is less than 29.3 mg / L, deep standard treatment has been achieved.

[0072] Example 5

[0073] Same as Example 1, except that: in the preparation method of the oil-resistant immobilized carrier, silicon aerogel is used instead of carbon aerogel, and the specific surface area of ​​silicon aerogel is 1000m 2 / g, the porosity is 85%, and the oil-resistant immobilized carrier C is finally prepared.

[0074] The reactor has been in operation for 6 months with stable treatment effects. When the ammonia nitrogen concentration in the system effluent is less than 0.95 mg / L, the TN concentration is less than 14.1 mg / L, and the COD concentration is less than 28.9 mg / L, deep treatment has been achieved.

[0075] Example 6

[0076] Same as Example 1, except that: in the preparation method of the oil-resistant immobilized carrier, cellulose aerogel is used instead of carbon aerogel, and the specific surface area of ​​cellulose aerogel is 900m 2 / g, the porosity was 95%, and the immobilized carrier D was finally prepared.

[0077] The reactor has been in operation for 6 months with stable treatment effects. When the ammonia nitrogen concentration in the system effluent is less than 0.87 mg / L, the TN concentration is less than 14.8 mg / L, and the COD concentration is less than 29.3 mg / L, deep standard treatment has been achieved.

[0078] Example 7

[0079] Same as Example 1, except that: in the preparation method of the oil-resistant immobilized carrier, the metal ion is Cu 2+ , prepare 3 mol / L copper chloride solution instead of ferric sulfate solution, and finally prepare immobilized carrier E.

[0080] The reactor has been in operation for 6 months with stable treatment effects. When the ammonia nitrogen concentration in the system effluent is less than 0.96 mg / L, the TN concentration is less than 14.5 mg / L, and the COD concentration is less than 28.6 mg / L, deep standard treatment has been achieved.

[0081] Example 8

[0082] Same as Example 1, except that: in the preparation method of the oil-resistant immobilized carrier, the metal ion used is Mg 2+ , prepare 4 mol / L magnesium sulfate solution instead of ferric sulfate solution. Finally, the immobilized carrier F was prepared.

[0083] The reactor has been in operation for 6 months with stable treatment effects. When the ammonia nitrogen concentration in the system effluent is less than 0.98 mg / L, the TN concentration is less than 14.4 mg / L, and the COD concentration is less than 28.3 mg / L, deep standard treatment has been achieved.

[0084] Comparative Example 1

[0085] The same as Example 1, except that the reactor was not loaded with granular activated carbon, and only the immobilized carrier A prepared in Example 1 was used. After six months of operation, the activated carbon's treatment effect on the refractory organic pollutants deteriorated because the refractory organic pollutants were not effectively treated and a virtuous cycle was not formed. The average ammonia nitrogen concentration in the effluent from the device was 1.6 mg / L, the average total nitrogen concentration was 13.9 mg / L, and the average COD concentration was 46.5 mg / L.

[0086] Comparative Example 2

[0087] The same method as Example 1 was used, except that the oil-resistant immobilized carrier A prepared in Example 1 was not used in the reactor, and only granular activated carbon was used. After six months of operation, the reactor failed to establish a virtuous cycle, and the wastewater treatment effect deteriorated. The average ammonia nitrogen concentration in the effluent was 3.9 mg / L, the average total nitrogen concentration was 22.1 mg / L, and the average COD concentration was 47.3 mg / L.

[0088] Comparative Example 3

[0089] The same method as Example 1 was used, except that the reactor did not use sludge that had undergone wall-breaking. After six months of operation, the reactor failed to establish a virtuous cycle, and the activated carbon's effectiveness in treating recalcitrant organic matter in the wastewater deteriorated. The average ammonia nitrogen concentration in the effluent from the device was 0.9 mg / L, the average total nitrogen concentration was 18.1 mg / L, and the average COD concentration was 49.5 mg / L.

[0090] Comparative Example 4

[0091] The same method as Example 1 was used, except that volcanic rock filler was used in the reactor instead of a combination of activated carbon and an oil-resistant immobilized carrier. After six months of operation, the average ammonia nitrogen concentration in the system effluent was 13.4 mg / L, the average total nitrogen concentration was 19.8 mg / L, and the average COD concentration was 45.5 mg / L.

[0092] Comparative Example 5

[0093] The same method as in Example 1 differed in that activated carbon, oil-resistant carrier, sludge supernatant, and salt-tolerant bacterial agent were added simultaneously, and the 24-hour aeration treatment at a dissolved oxygen concentration of 6 mg / L was omitted. After six months of operation, the treatment effect deteriorated, with the system effluent ammonia nitrogen concentration reaching 3.5 mg / L, TN concentration less than 16.2 mg / L, and COD concentration less than 35.8 mg / L.

[0094] Comparative Example 6

[0095] This comparative example was the same as Example 1, except that, during the preparation of the oil-resistant immobilized carrier, the aerogel was not subjected to the pretreatment process of step (1), and the humic acid modification process of step (2) was directly performed. After the reactor operated for 6 months, the average ammonia nitrogen concentration in the system effluent was 16.4 mg / L, the average total nitrogen concentration was 36.4 mg / L, and the average COD concentration was 43.3 mg / L.

[0096] Comparative Example 7

[0097] This comparative example was the same as Example 1, except that, during the preparation of the oil-resistant immobilized support, humic acid was not used during the modification step (2), and only Fe(OH)3 solution was used. After six months of operation, the average ammonia nitrogen concentration in the system effluent was 15.7 mg / L, the average total nitrogen concentration was 37.2 mg / L, and the average COD concentration was 44.6 mg / L.

[0098] Comparative Example 8

[0099] This is the same as Example 1, except that in this comparative example, during the preparation of the oil-resistant immobilized support, the post-reaction washing step (2) was performed to a neutral, rather than weakly alkaline, state. After six months of operation, the system effluent had an average ammonia nitrogen concentration of 13.4 mg / L, an average total nitrogen concentration of 34.7 mg / L, and an average COD concentration of 45.1 mg / L.

[0100] Comparative Example 9

[0101] This comparative example was the same as Example 1, except that, during the preparation of the oil-resistant immobilized carrier, the modified aerogel in step (3) was not loaded with metal ions. After six months of operation, the system effluent had an average ammonia nitrogen concentration of 17.9 mg / L, an average total nitrogen concentration of 38.4 mg / L, and an average COD concentration of 41.9 mg / L.

[0102] Comparative Example 10

[0103] This comparative example was the same as Example 1, except that, in step (4), rhamnolipid was used in place of the rhamnolipid-producing Pseudomonas aeruginosa fermentation broth during the preparation of the immobilized support. After six months of operation, the average ammonia nitrogen concentration in the system effluent was 16.1 mg / L, the average total nitrogen concentration was 35.2 mg / L, and the average COD concentration was 45.3 mg / L.

Claims

1. A method for treating wastewater containing refractory substances to achieve high-quality treatment, comprising the following steps: (1) Filling the reactor with activated carbon at 30% to 70% of its effective volume; (2) breaking the cell wall of the activated sludge used to treat refractory organic pollutants to release the substances in the cells, precipitating or filtering to remove impurities, and adding the remaining liquid to step (1), and treating it with simmering and exposure for 12 to 24 hours, and controlling the dissolved oxygen concentration to be above 5 mg / L; (3) adding an oil-resistant immobilized carrier to the reaction system of step (2), and simultaneously inoculating a salt-tolerant bacterial agent capable of treating organic pollutants and nitrogen-containing pollutants, and continuously aerating for 5 to 7 days under the conditions of dissolved oxygen of 2 to 6 mg / L, pH of 7 to 9, and temperature of 25 to 40° C., and then treating the wastewater according to the set hydraulic retention time; The oil-resistant immobilized carrier is prepared according to the following method: (a) placing the aerogel in an acetic acid solution for reaction, taking it out and washing it to neutrality; (b) dissolving humic acid in a Fe(OH)3 solution, adding the aerogel, reacting it at 50-70°C, and washing it to weak alkalinity to obtain a modified aerogel; (c) loading an active metal on the modified aerogel to obtain a metal-loaded carrier; (d) adsorbing sugar ester-producing microorganisms on the metal-loaded carrier, and drying after the adsorption is completed to obtain an immobilized carrier.

2. The method according to claim 1, characterized in that In step (1), activated carbon is loaded in an amount of 40% to 60% of the effective volume of the reactor.

3. The method according to claim 1, characterized in that In step (2), the dissolved oxygen concentration is controlled at 5-7 mg / L.

4. The method according to claim 1, wherein In step (1), the activated carbon is coal-based activated carbon with a particle size of 2 to 8 mm and a specific surface area of ​​600 to 1000 m 2 / g, iodine value 600-1000 mg / g, methylene blue 90-120 mg / g.

5. The method according to claim 1, characterized in that In step (2), the cell wall breaking treatment is at least one of excessive aeration, mechanical stirring, ultrasonic crushing or chemical penetration with the addition of a surfactant.

6. The method according to claim 1, characterized in that In step (3), the metal content of the oil-resistant immobilized carrier as oxide accounts for 1% to 20% of the mass of the modified aerogel, the humic acid accounts for 0.1% to 10% of the mass of the modified aerogel, and the sugar ester-producing microorganisms account for 5% to 50% of the mass of the modified aerogel.

7. The method according to claim 6, characterized in that In step (3), the oil-resistant immobilized carrier and the sugar ester-producing microorganisms account for 10% to 30% of the mass of the modified aerogel.

8. The method according to claim 1, characterized in that The oil-resistant immobilized carrier is added according to a solid-liquid mass concentration of 20 to 50 mg / L after addition.

9. The method according to claim 1, characterized in that The aerogel in step (a) is at least one of carbon aerogel, silicon aerogel, and cellulose aerogel.

10. The method according to claim 9, characterized in that The aerogel in step (a) is carbon aerogel.

11. The method according to claim 1, characterized in that The concentration of the acetic acid solution in step (a) is 1.0 to 2.0 mol / L; the aerogel is immersed in the acetic acid solution for reaction at a temperature of 30 to 50° C. and a reaction time of 1.0 to 2.0 h.

12. The method according to claim 1, characterized in that The concentration of the Fe(OH)3 solution in step (b) is 0.5-0.8 mol / L, and the mass ratio of the Fe(OH)3 solution to humic acid is 1:1-3:

1.

13. The method according to claim 1, wherein Step (b) immersing the aerogel in a mixed system of humic acid and Fe(OH)3 solution, shaking in a water bath at 50-70°C for 3-5 hours; and taking out and washing the aerogel until the pH value is weakly alkaline.

14. The method according to claim 13, characterized in that In step (b), washing is performed until the pH value reaches 7.6 to 8.

0.

15. The method according to claim 1, wherein The active metal in step (c) is Cu 2+ 、Fe 2+ Mg 2+ At least one of .

16. The method according to claim 15, characterized in that The active metal in step (c) is Fe 2+ .

17. The method according to claim 1, wherein Step (d) is to immerse the metal-loaded carrier in the fermentation liquid of the sugar ester-producing microorganism for adsorption growth of the bacteria, with the volume ratio of the metal-loaded carrier to the fermentation liquid being 1:1-3; the adsorption growth conditions are: temperature of 20-38°C, pH of 6.0-8.5, and reaction time of 12-36 hours; and the drying conditions are drying at 35-50°C for 24-48 hours.

18. The method according to claim 17, characterized in that In step (d), the adsorption growth conditions are: temperature 20-30° C., pH 6.0-7.

0.

19. The method according to claim 1, wherein The sugar ester-producing microorganism in step (d) is a microorganism that ferments and produces at least one sugar ester selected from rhamnosyl ester, trehalose biosurfactant, sophorolipid and sucrose biosurfactant.

20. The method according to claim 1, wherein The sugar ester-producing microorganism in step (d) is at least one of Pseudomonas aeruginosa that produces rhamnosyl ester and Pseudomonas aeruginosa that produces trehalose lipid.

21. The method according to claim 1, wherein In step (3), the inoculation amount of the salt-tolerant bacteria agent is inoculated at a ratio of 0.01% to 0.05% of the volume of the salt-tolerant bacteria agent to the effective volume of the sewage treatment device.

22. The method according to claim 1, wherein The sewage is at least one of the effluent from the secondary biochemical unit, RO concentrated water, and circulating water wastewater. The water quality of the sewage is: ammonia nitrogen concentration of 10-20 mg / L, total nitrogen of 30-50 mg / L, COD concentration of 60-150 mg / L, and B / C less than 0.

3.

23. The method according to claim 1, wherein The sewage depth compliance means that after treatment, the ammonia nitrogen concentration in the effluent is less than 1 mg / L, the total nitrogen concentration is less than 15 mg / L, and the COD concentration is less than 30 mg / L.