Treatment method of HNIW wastewater

Abstract

The invention relates to a treatment method of HNIW wastewater, and belongs to the technical field of wastewater treatment. The invention provides a method for treating HNIW wastewater. The method mainly comprises the steps of physical adsorption, alkaline hydrolysis, microbial immobilization, microbial domestication and the like. Macroporous adsorption resin and fluorine-containing silane are adopted for adsorption, and the COD value can be reduced under mutual promotion of the macroporous adsorption resin and the fluorine-containing silane; meanwhile, the macroporous adsorption resin can be used as an implantation point or an attachment point of compound microorganisms, and a biological membrane can be formed on the macroporous adsorption resin.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a method for treating HNIW wastewater. Background Technology

[0002] Hexanitrohexaazaisowroughtane (HNIW) is a high-energy-density compound with a cage-like, three-dimensional polycyclic nitramine structure. It is currently recognized worldwide as the single-element explosive with the highest energy density for engineering applications. Its production and use generate large quantities of HNIW wastewater. HNIW wastewater has a highly complex composition, characterized by high toxicity, high pH, ​​high concentration, high color, high chemical oxygen demand (COD), and is difficult to biodegrade, posing a threat to humans, animals, and plants.

[0003] Currently, wastewater treatment technologies both domestically and internationally mainly include physical, chemical, and biochemical methods. Traditional physical methods are simple to operate and have fast reaction speeds, but they are costly and cause serious secondary pollution. Chemical methods have fast treatment rates and can tolerate high pollutant concentrations, but they consume a lot of energy and are difficult to industrialize. Biological methods are safe to operate and effective, and can achieve complete mineralization of pollutants, but they also have problems such as low tolerance of microorganisms to pollutant concentrations and slow degradation rates. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a method for treating HNIW wastewater to reduce COD and chloroform in the wastewater.

[0005] On the one hand, the present invention provides a method for treating HNIW wastewater, comprising the following steps:

[0006] S1: Physical adsorption, using macroporous adsorption resin and fluorinated silane for adsorption; the weight ratio of the macroporous adsorption resin to the fluorinated silane is (5-15):1;

[0007] S2: Alkaline hydrolysis, using alkaline substances to adjust pH and BOD5 / COD;

[0008] S3: Microbial immobilization, using glucose, urea, phosphate, and compound microorganisms for microbial culture;

[0009] S4: Microbial acclimatization, adding compound microorganisms, and the biological filter acclimatization is completed after the COD of the effluent stabilizes.

[0010] Furthermore, in step S2, the pH value is controlled at 11-13, and the reaction time is 1-6 hours.

[0011] Furthermore, in step S2, the BOD5 / COD ratio is controlled to be above 0.4.

[0012] Further, in step S3, the composite microorganisms are Methylobacterium, Hydrophage, and Thiobacterium thiooxidans.

[0013] Furthermore, the *Methylobacterium* genus was selected as *Organophilic Methylobacterium*; the *Hydrophage* genus was selected as *Hydrophage aurantiacus* and *Hydrophage pseudo-yurantiacus*; and the *Thiobacillus* genus was selected as *Thiobacillus thiopureum* and *Thiobacillus naples*.

[0014] Furthermore, in step S3, the influent COD is maintained at 500-600 mg / L, the pH value is controlled at 6.5-7.7, and the C:N:P ratio is 100:5:1. Simultaneously, sluggish aeration is carried out to maintain DO at 6-8 mg / L.

[0015] Furthermore, the COD in the wastewater effluent is reduced to below 63.1 mg / L, with a removal rate of over 99.47%.

[0016] Furthermore, the macroporous adsorption resin is nonpolar or weakly polar, and the specific surface area of ​​the macroporous adsorption resin is 500-600 m². 2 / g.

[0017] Furthermore, the non-polar macroporous adsorption resins are selected from D101, X-5, and HP-20;

[0018] The weakly polar macroporous adsorption resin is DM130.

[0019] Furthermore, the fluorinated silane is selected from 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 3,3,3-trifluoropropylmethyldimethoxysilane, and 3,3,3-trifluoropropyltrimethoxysilane.

[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0021] 1. This invention provides a method for treating HNIW wastewater, mainly including steps such as physical adsorption, alkaline hydrolysis, microbial immobilization, and microbial acclimatization. Macroporous adsorption resin and fluorinated silane are used for adsorption; the two promote each other to reduce the COD value. Simultaneously, the macroporous adsorption resin can serve as a substrate or attachment point for the composite microorganisms, forming a biofilm on the resin. The COD of the effluent is reduced to below 63.1 mg / L, with a removal rate exceeding 99.47%, and chloroform is not detected.

[0022] 2. The composition for treating HNIW wastewater provided by this invention mainly consists of macroporous adsorption resin, which can adsorb relatively complex organic components in the wastewater, thereby reducing the chemical oxygen demand (COD). Simultaneously, the macroporous adsorption resin can serve as a carrier for complex microorganisms in subsequent treatment, ensuring the quantity of these microorganisms and ultimately maintaining the final COD value of the wastewater at a minimum. In this invention, the composition for treating HNIW wastewater also contains some fluorosilanes, which, with the promotion of these fluorosilanes, can further reduce the COD value in the wastewater.

[0023] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0024] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0025] Figure 1 EMSE image of macroporous adsorption resin without attached biofilm;

[0026] Figure 2 This is an EMSE image of the biofilm attached to the macroporous adsorption resin in Example 1. Detailed Implementation

[0027] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0028] Hexanitrohexaazaisowrtzane (HNIW) is a high-energy-density compound with a cage-like, three-dimensional polycyclic nitramine structure. It is currently recognized worldwide as the single-element explosive with the highest energy density for engineering applications. Its production and use generate large quantities of HNIW wastewater. HNIW wastewater has a highly complex composition, characterized by high toxicity, high pH, ​​high concentration, high color, and high chemical oxygen demand (COD). It is difficult to directly biodegrade and therefore poses a significant hazard.

[0029] Currently, the main technologies for treating HNIW wastewater both domestically and internationally include physical, chemical, and biochemical methods. Traditional physical methods are simple to operate and have a fast reaction speed, but they are costly and cause serious secondary pollution. Chemical methods have a fast treatment rate and can tolerate high pollutant concentrations, but they consume a lot of energy and are difficult to industrialize. Biological methods are safe to operate and effective, and can achieve complete mineralization of pollutants, but they also have problems such as low tolerance of microorganisms to pollutant concentrations and slow degradation rates.

[0030] Therefore, the present invention provides a composition for treating HNIW wastewater, comprising a macroporous adsorption resin and a fluorinated silane.

[0031] Compared with existing technologies, the composition for treating HNIW wastewater provided by this invention mainly consists of macroporous adsorption resin, which can adsorb relatively complex organic components in the wastewater, thereby reducing the chemical oxygen demand (COD). Simultaneously, the macroporous adsorption resin can serve as a carrier for complex microorganisms in subsequent treatment, ensuring the quantity of these microorganisms and ultimately maintaining the COD value of the final wastewater at a minimum. In this invention, the composition for treating HNIW wastewater also contains some fluorosilanes, which, with the promotion of these fluorosilanes, can further reduce the COD value of the wastewater.

[0032] Specifically, the weight ratio of the macroporous adsorption resin to the fluorinated silane is (5-15):1.

[0033] Preferably, the weight ratio of the macroporous adsorption resin to the fluorinated silane is (10-12):1.

[0034] It should be noted that in this invention, macroporous adsorption resin is the main component, supplemented by fluorinated silane; the two are compounded together to work synergistically. The weight ratio of macroporous adsorption resin to fluorinated silane can be controlled, and can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, or 15:1. When the content of macroporous adsorption resin is low, the adsorption effect is poor, and the reduction in COD value is limited; when the amount of fluorinated silane is too high or too low, the promoting effect is poor.

[0035] Specifically, the macroporous adsorption resin has a specific surface area of ​​500-600 m². 2 / g.

[0036] Preferably, the macroporous adsorption resin is nonpolar or weakly polar.

[0037] Preferably, the non-polar macroporous adsorption resin is selected from D101, X-5 and HP-20.

[0038] Preferably, the weakly polar macroporous adsorption resin is DM130.

[0039] It should be noted that, in this invention, the macroporous adsorption resin is selected to be non-polar or weakly polar, and its specific surface area needs to be controlled to be 500-600 m². 2 / g, which can be 500m 2 / g、550m 2 / g or 600m 2 / g. When choosing a polar compound or with a specific surface area less than 500m². 2 / g or higher than 600m 2 At / g, the reduction in COD value is limited.

[0040] Specifically, the fluorinated silane is selected from 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 3,3,3-trifluoropropylmethyldimethoxysilane, and 3,3,3-trifluoropropyltrimethoxysilane.

[0041] It should be noted that in this invention, fluorinated silanes have two functions: firstly, they enhance the adsorption capacity of macroporous adsorption resins, enabling them to adsorb more complex organic components in wastewater; secondly, they promote the attachment of complex microorganisms to macroporous adsorption resins, further reducing the COD value in wastewater.

[0042] This invention provides a method for treating HNIW wastewater, comprising the following steps:

[0043] S1: Physical adsorption, using macroporous adsorption resin and fluorinated silane for adsorption;

[0044] S2: Alkaline hydrolysis, using alkaline substances to adjust pH and BOD5 / COD;

[0045] S3: Microbial immobilization, using glucose, urea, phosphate, and compound microorganisms for microbial culture;

[0046] S4: Microbial acclimatization, adding compound microorganisms, and the biological filter acclimatization is completed after the COD of the effluent stabilizes.

[0047] Compared with existing technologies, this invention provides a method for treating HNIW wastewater, mainly including steps such as physical adsorption, alkaline hydrolysis, microbial immobilization, and microbial domestication. In step S1, macroporous adsorption resin and fluorinated silane are used for adsorption, and the two promote each other to reduce the COD value. When the content of macroporous adsorption resin is low, the adsorption effect is poor, and the reduction of COD value is limited; when the amount of fluorinated silane is too high or too low, the promoting effect is poor. At the same time, macroporous adsorption resin can serve as a landing site or attachment point for composite microorganisms, and a biofilm can be formed on the macroporous adsorption resin.

[0048] Specifically, in step S2, the pH value is controlled at 11-13, and the reaction time is 1-6 hours.

[0049] It should be noted that in step S2, a 30% sodium hydroxide solution needs to be added and stirred until homogeneous. As the initial pH of alkaline hydrolysis increases from 10 to 13, the degradation rate of chloroform gradually accelerates. When the experimental pH is greater than 13, a large amount of NaOH needs to be added to adjust the pH, which will result in excessively high salinity in the wastewater, affecting the removal effect of subsequent biochemical processes.

[0050] In step S2, HNIW (hexanitrohexaazaisowulzane C 12 H 12 N 12 O 24 Chloroform (CHCl3) can be hydrolyzed under alkaline conditions to yield smaller organic molecules, as shown in the following reaction:

[0051] HNIW+24NaOH→12HCOONa+12NaNO2+6H2O+3N2

[0052] CHCl3+4NaOH→HCOONa+3NaCl+2H2O

[0053] Specifically, in step S2, the BOD5 / COD ratio is controlled to be above 0.4.

[0054] It should be noted that in this invention, the BOD5 / COD ratio must be controlled above 0.4. BOD5 (determined using the five-day incubation method (HJ505-2009)) refers to the amount of oxygen required for microorganisms to decompose organic matter in a water sample at 20°C, usually expressed in mg / L. COD represents chemical oxygen demand (determined using the potassium dichromate titration method (HZ-HJ-SZ-0108)). Only when the BOD5 / COD ratio is above 0.4 can the requirements for biological treatment of influent be met; that is, only then can the composite microorganisms survive and accumulate on the macroporous adsorption resin, thus better reducing the COD value.

[0055] Specifically, in step S3, the composite microorganisms are Methylobacterium, Hydrophage, and Thiobacterium thiooxidans.

[0056] It should be noted that, in this invention, the genus *Methylobacterium* is selected as *Organophilic Methylobacterium*; the genus *Hydrophage* can utilize hydrogen as an energy source for oxidative metabolism, and can also utilize various organic substances as carbon and energy sources, and can be selected as *Hydrophage xanthophyte* or *Hydrophage pseudo-yanthophyte*; the genus *Thiobacillus* can be selected as *Thiobacillus thioparus* or *Thiobacillus naples*.

[0057] Specifically, in step S3, the influent COD is maintained at 500-600 mg / L, the pH value is controlled at 6.5-7.7, and the C:N:P ratio is 100:5:1. Simultaneously, aeration is carried out to maintain DO at 6-8 mg / L, and the culture is carried out for 15 days.

[0058] It should be noted that after the addition in step S2 is completed, microbial cultivation should be carried out only after controlling the pH value and the BOD5 / COD ratio. During the cultivation process, the influent COD needs to be maintained at 500-600 mg / L, and the C:N:P ratio should be adjusted to 100:5:1 using glucose, urea, and phosphate. The added microorganisms are Methylobacterium, Hydrophage, and Thiobacterium thiooxidans. Simultaneously, aeration should be performed to maintain DO (dissolved oxygen) at 6-8 mg / L. After 15 days of cultivation, a biofilm will form on the macroporous adsorption resin.

[0059] During the microbial acclimatization stage, it is also necessary to control the pH value at 6.5-7.7, C:N:P = 100:5:1, and add 30-40% compound microorganisms to reduce COD in the final stage. After the COD stabilizes, the acclimatization is completed and the water is discharged.

[0060] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0061] Example 1

[0062] A method for treating HNIW wastewater includes the following steps, wherein the HNIW wastewater is taken from Hubei Dongfang Chemical Plant, and the water sample is dark red, has a pungent odor, and has a COD of approximately 1.2 × 10⁻⁶. 4 mg / L, pH 7.26, BOD5 / COD 0.002, chloroform content 3000 mg / L.

[0063] S1: Physical adsorption, using macroporous adsorption resin and fluorinated silane for adsorption;

[0064] The macroporous adsorption resin and the fluorinated silane have a weight ratio of 5:1, and the macroporous adsorption resin is a non-polar D101 with a specific surface area of ​​550 m². 2 / g; The fluorinated silane is 1H,1H,2H,2H-perfluorooctyltriethoxysilane;

[0065] S2: Alkaline hydrolysis, using alkaline substances to adjust pH and BOD5 / COD;

[0066] Add a 30% sodium hydroxide solution, control the pH value at 11, the reaction time is 4 hours, and the BOD5 / COD ratio is controlled at 0.4.

[0067] S3: Microbial immobilization, with influent COD maintained at 500 mg / L and pH controlled at 7.2. Microbial culture is carried out using glucose, urea, phosphate, and compound microorganisms; C:N:P = 100:5:1. Simultaneous aeration is performed to maintain DO at 6-8 mg / L, and culture is carried out for 15 days; biofilm is formed on macroporous adsorption resin.

[0068] The composite microorganisms are organic methylbacterium, yellow hydrogen phage, and sulfur-excreting thiobacillus;

[0069] S4: Microbial acclimatization. Add 30% compound microorganisms. Once the COD of the effluent stabilizes, the acclimatization of the biological filter is complete.

[0070] Examples 2-8, Comparative Examples 1-4

[0071] Examples 2-8 and Comparative Examples 1-4 were prepared in largely the same way as Example 1, with the differences shown in Table 1.

[0072] Table 1. Preparation parameters for Examples 1-8 and Comparative Examples 1-4

[0073]

[0074]

[0075] Example 9

[0076] The preparation process of Example 9 is largely the same as that of Example 1, except that in step S2 of Example 9, the pH value is controlled at 12.5.

[0077] Example 10

[0078] The preparation process of Example 10 is largely the same as that of Example 1, except that in step S2 of Example 10, the pH value is controlled at 13.

[0079] Comparative Example 5

[0080] The preparation process of Comparative Example 5 is largely the same as that of Example 1, except that in step S2 of Comparative Example 5, the pH value is controlled at 10.

[0081] Comparative Example 6

[0082] The preparation process of Comparative Example 6 is largely the same as that of Example 1, except that in step S2 of Comparative Example 6, the BOD5 / COD ratio is controlled to be 0.2.

[0083] Comparative Example 7

[0084] The preparation process of Comparative Example 7 is largely the same as that of Example 1, except that in Comparative Example 7, *Hydrogenophages xanthophyte* is replaced with *Hydrogenophilic nitrosopterus*.

[0085] Comparative Example 8

[0086] The preparation process of Comparative Example 8 is largely the same as that of Example 1, except that Comparative Example 8 does not contain fluorinated silanes.

[0087] Comparative Example 9

[0088] The preparation process of Comparative Example 9 is largely the same as that of Example 1, except that step S2 is not included in Comparative Example 9.

[0089] Comparative Example 10

[0090] The preparation process of Comparative Example 10 is largely the same as that of Example 1, except that steps S3 and S4 are not included in Comparative Example 10.

[0091] Performance testing

[0092] The above Examples 1-10 and Comparative Examples 1-9 were subjected to performance testing, mainly for COD and chloroform. The test results are shown in Table 2.

[0093] Table 2 Performance Test Results

[0094] Group COD (mg / L) Chloroform (mg / L) Example 1 63.1 Not detected Example 2 55.4 Not detected Example 3 42.3 Not detected Example 4 43.4 Not detected Example 5 42.7 Not detected Example 6 43.9 Not detected Example 7 41.9 Not detected Example 8 54.2 Not detected Example 9 42.5 Not detected Example 10 45.4 Not detected Comparative Example 1 385.4 Not detected Comparative Example 2 398.4 Not detected Comparative Example 3 402.5 Not detected Comparative Example 4 375.4 Not detected Comparative Example 5 396.4 102.4 Comparative Example 6 375.9 Not detected Comparative Example 7 388.1 Not detected Comparative Example 8 445.3 Not detected Comparative Example 9 3898.6 2545.5 Comparative Example 10 504.5 Not detected

[0095] Combined with Examples 1-10 and Comparative Examples 1-10 and referring to Table 2 and Figure 1-2 It can be seen that, using the wastewater treatment composition and method provided by this invention, under the mutual promotion of macroporous adsorption resin and fluorinated silane, and combined with steps such as alkaline hydrolysis, microbial immobilization, and microbial domestication, the composite microorganisms can form a biofilm on the macroporous adsorption resin, exhibiting a granular form; this can reduce COD from 1.2 × 10⁻⁶. 4 The concentration of chloroform was reduced to below 63.1 mg / L, with a removal rate of over 99.47%, and no chloroform was detected.

[0096] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for treating HNIW wastewater, characterized in that, Includes the following steps, S1: Physical adsorption, using macroporous adsorption resin and fluorinated silane for adsorption; the weight ratio of the macroporous adsorption resin to the fluorinated silane is (5-15):1; S2: Alkaline hydrolysis, using alkaline substances to adjust pH and BOD5 / COD; S3: Microbial immobilization, using glucose, urea, phosphate, and compound microorganisms for microbial culture; S4: Microbial acclimatization, adding compound microorganisms, and the biological filter acclimatization is completed after the COD of the effluent stabilizes.

2. The method for treating HNIW wastewater according to claim 1, characterized in that, In step S2, the pH value is controlled at 11-13, and the reaction time is 1-6 hours.

3. The method for treating HNIW wastewater according to claim 1, characterized in that, In step S2, the BOD5 / COD ratio is controlled to be above 0.

4.

4. The method for treating HNIW wastewater according to claim 1, characterized in that, In step S3, the composite microorganisms are Methylobacterium, Hydrophage, and Thiobacterium thiooxidans.

5. The method for treating HNIW wastewater according to claim 4, characterized in that, The *Methylobacterium* genus was selected as *Organophilic Methylobacterium*; the *Hydrophage* genus was selected as *Hydrophage aurantiacus* and *Hydrophage pseudo-yurantiacus*; and the *Thiobacillus* genus was selected as *Thiobacillus thiooxidans* and *Thiobacillus naples*.

6. The method for treating HNIW wastewater according to claim 1, characterized in that, In step S3, the influent COD is maintained at 500-600 mg / L, the pH value is controlled at 6.5-7.7, and the C:N:P ratio is 100:5:

1. Simultaneously, sludge aeration is carried out to maintain DO at 6-8 mg / L.

7. A method for treating HNIW wastewater according to any one of claims 1-6, characterized in that, The COD in the wastewater effluent is reduced to below 63.1 mg / L, and the removal rate can reach over 99.47%.

8. The method for treating HNIW wastewater according to claim 1, characterized in that, The macroporous adsorption resin is nonpolar or weakly polar, and its specific surface area is 500-600 m². 2 / g.

9. The method for treating HNIW wastewater according to claim 8, characterized in that, The nonpolar macroporous adsorption resins were selected from D101, X-5, and HP-20; The weakly polar macroporous adsorption resin is DM130.

10. The method for treating HNIW wastewater according to claim 1, characterized in that, The fluorinated silane is selected from 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 3,3,3-trifluoropropylmethyldimethoxysilane and 3,3,3-trifluoropropyltrimethoxysilane.

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