CN110550736A - Method for pretreating high-concentration fluoroquinolone antibiotic wastewater by using iron-carbon microelectrolysis coupling anaerobic acid production fermentation process - Google Patents

Abstract

The invention couples the iron-carbon micro-electrolysis and the anaerobic acid-producing fermentation process, places the two technologies in the same reaction system, and promotes each other to play a role together, which can effectively shorten the treatment process, save space and time, and can effectively treat high concentration Fluoroquinolone antibiotic wastewater. Among them, iron-carbon micro-electrolysis utilizes micro-galvanic cell reaction to produce [H], H ₂ and Fe ²⁺ and other substances with reducing effect, which can degrade macromolecular organic pollutants in water, reduce biological toxicity of wastewater and improve the biodegradability of wastewater. And the co-precipitation of ferrous iron and ferric hydroxide can also remove some antibiotics. The anaerobic acidogenic fermentation process uses the anaerobic biological treatment process, which can be divided into three consecutive stages, namely hydrolysis, acidification and methane production. The reaction is controlled in the first two stages through artificial regulation. The chemical structure and properties of the waste change, which provides a stable basis for microbial treatment, and can also replace the acidic reagent to provide a suitable acidic environment for the iron-carbon micro-electrolysis reaction.

Description

An iron-carbon micro-electrolysis coupled anaerobic acid production fermentation process for pretreatment of high-concentration fluorine Method for quinolone antibiotic wastewater

technical field

The invention relates to the field of sewage treatment, in particular to the application of an iron-carbon micro-electrolysis coupled anaerobic acid-producing fermentation process in the pretreatment of high-concentration fluoroquinolone antibiotic wastewater.

Background technique

Fluoroquinolone antibiotics are a class of synthetic antibacterial drugs, especially ciprofloxacin, which is widely used in human disease prevention, livestock and aquaculture because of its broad-spectrum antibacterial ability and good efficacy. . With the increasing demand for antibiotics, fluoroquinolone antibiotics are produced and synthesized in large quantities. Such drugs will produce a large number of intermediate products during the production process, and the wastewater contains high concentrations of antibiotic residues, which have poor biodegradability, complex components and high toxicity. It is regarded as a type of high-concentration refractory organic wastewater. However, it is difficult to directly and effectively treat high-concentration fluoroquinolone antibiotic wastewater by conventional treatment technologies at present, which will not only cause serious impact on the biological treatment unit, but may even lead to the collapse of subsequent biochemical processes, making it difficult to operate stably. Therefore, it is of great practical significance to develop a pretreatment process for high-concentration fluoroquinolone antibiotic wastewater.

At present, the treatment methods of high-concentration fluoroquinolone antibiotics, especially ciprofloxacin-resistant wastewater, mainly include physical adsorption, chemical oxidation and biological treatment. Among them, the physical adsorption method, such as using diatomaceous earth to treat ciprofloxacin wastewater, can only achieve the transfer of ciprofloxacin but cannot remove ciprofloxacin. If the adsorbate is not properly treated, it is easy to cause secondary pollution. Chemical oxidation methods such as optical Fenton technology, although this type of process can destroy the chemical structure of fluoroquinolone antibiotics and reduce the toxicity of wastewater, but there are disadvantages of difficult process control, high operating costs and high maintenance costs. Biological treatment is widely used as a mature and economical antibiotic treatment method. However, because fluoroquinolone antibiotics have a strong inhibitory effect on microorganisms, it is difficult to use biological treatment alone to exert its advantages and cannot achieve ideal treatment effects.

SUMMARY OF THE INVENTION

The problem to be solved by the present invention is to solve the problem in the field of fluoroquinolone antibiotic pharmaceutical wastewater that "conventional treatment technology is difficult to directly effectively treat high-concentration fluoroquinolone antibiotic wastewater". Concentration of fluoroquinolone antibiotics, especially ciprofloxacin antibiotic wastewater and part of COD, can achieve a better pretreatment effect.

In order to solve this problem, the present invention provides a kind of iron-carbon micro-electrolysis coupled anaerobic acid-producing fermentation process, and the method for pretreating high-concentration fluoroquinolone antibiotic wastewater, comprising the following steps:

1. Take anaerobic activated sludge (pH 7.0~8.0), and domesticate it with a carbon-rich nutrient matrix (COD content of 5000~8000mg/L). The volume ratio of carbon-rich nutrient matrix to sludge is 10:1~15 :1;

2. Introduce high-purity nitrogen to ensure that the reaction system is in an anaerobic state. The reaction temperature was 37±1°C, and the reaction time was 10 to 12 hours;

3. Discharge the supernatant after natural precipitation, and retain the lower sludge, which is the required anaerobic acid production stage sludge (pH between 4.0 and 5.5);

4. The sludge in the anaerobic acid production stage is mixed with high-concentration fluoroquinolone antibiotic wastewater for anaerobic fermentation, and the volume ratio of wastewater to sludge is 15:1~20:1;

5. Add zero-valent nano-iron and granular activated carbon (ie, iron-carbon mixture), the mass ratio of zero-valent nano-iron and granular activated carbon is 1:1; the mass ratio of iron-carbon mixture to sludge volatile solids in the anaerobic acid production stage 1:1~1.5:1;

6. Pour in high-purity nitrogen to ensure that the reaction system is in an anaerobic state. The reaction temperature is 37±1°C, and the reaction time is 6 to 8 hours.

7. After the reaction is completed, it is allowed to settle, and the supernatant is the effluent after the pretreatment of the high-concentration fluoroquinolone antibiotic wastewater.

The main features of the present invention are:

1. By coupling iron-carbon micro-electrolysis (zero-valent nano-iron and granular activated carbon) with the anaerobic acid production fermentation process, the iron-carbon contact is used to generate microcurrent and its redox effect, anaerobic activated sludge adsorption and anaerobic acid production. Pretreatment of high-concentration fluoroquinolone antibiotic wastewater by oxygen microbial degradation, etc., the concentration of fluoroquinolone antibiotics in the effluent is greatly reduced, which can lay the foundation for subsequent treatment of the effluent after pretreatment.

2. The optimum pH for the iron-carbon micro-electrolysis reaction is acidity. The present invention utilizes the characteristics of the acid-producing fermentation process stage, and uses the sludge in the hydrolysis and acidification stage (pH at 4.0-5.5) to replace the acidifying reagent to provide an acidic environment.

The invention couples the iron-carbon micro-electrolysis and the anaerobic acid-producing fermentation process, places the two technologies in the same reaction system, and promotes each other to play a role together, which can effectively shorten the treatment process, save space and time, and can effectively treat high concentration Fluoroquinolone antibiotic wastewater. Among them, iron-carbon micro-electrolysis utilizes micro-galvanic cell reaction to produce [H], H ₂ and Fe ²⁺ and other substances with reducing effect, which can degrade macromolecular organic pollutants in water, reduce biological toxicity of wastewater and improve the biodegradability of wastewater. And the co-precipitation of ferrous iron and ferric hydroxide can also remove some antibiotics. The anaerobic acidogenic fermentation process uses the anaerobic biological treatment process, which can be divided into three consecutive stages, namely hydrolysis, acidification and methane production. The reaction is controlled in the first two stages through artificial regulation. The chemical structure and properties of the waste change, which provides a stable basis for microbial treatment, and can also replace the acidic reagent to provide a suitable acidic environment for the iron-carbon micro-electrolysis reaction.

Detailed ways

The present invention will be described in detail below according to specific embodiments. The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

The anaerobic activated sludge in the examples was taken from an up-flow anaerobic sludge bed reactor in a citric acid plant. The carbon-rich nutrient matrix uses glucose as the carbon source (COD is 5000-8000 mg/L), ammonium chloride and potassium dihydrogen phosphate as the nitrogen and phosphorus sources, and the dosage ratio is C:N:P=200:5:1 , and add 1mL/L trace element solution and vitamin solution. Trace element solution (g/L): H ₃ BO ₃ , 0.05; ZnCl ₂ , 0.05; CuCl ₂ ·2H ₂ O, 0.038; MnCl ₂ ·4H ₂ O, 0.05; (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H _2O , 0.05; _AlCl3 , 0.05; _CoCl2.6H2O , 0.05 _{; NiCl2.6H2O} , _{0.092 ; Na2SeO3.5H2O} , _0.1 . Vitamin solution (mg/L): biotin, 2; folic acid, 2; B1, 5; B2, 5; B6, 10; B12, 0.1; niacin, 5; para-aminobenzoic acid, 5; lipoic acid, 5; Pantothenic acid, 5.

Example 1

In this example, the COD of the carbon-rich nutrient substrate is 5000 mg/L, the antibiotic wastewater is taken from the laboratory self-prepared water, and the concentration of ciprofloxacin is 100 mg/L. The iron-carbon micro-electrolysis coupled anaerobic sludge treatment method is adopted, and the specific steps are as follows:

(1) Take the anaerobic activated sludge into the anaerobic bottle, add carbon-rich nutrient substrate and mix with the sludge for domestication. The volume ratio of the anaerobic activated sludge to the carbon-rich nutrient substrate is 1:10. Introduce nitrogen for 15 minutes to remove oxygen, seal and acclimate at 37±1°C for 12 hours.

(2) Remove the supernatant, take the lower layer of sludge and mix it with the above-mentioned ciprofloxacin antibiotic wastewater in a volume ratio of 1:20, and add zero-valent nano-iron and Granular activated carbon (iron carbon ratio 1:1). Pour nitrogen into the anaerobic bottle for 15 minutes to remove oxygen, seal it and place it in 37±1℃, 120r/min for anaerobic acid production and fermentation for 8 hours.

By measuring the influent and effluent, the removal rate of ciprofloxacin reaches 96%, and the removal rate of COD reaches 28%, which has efficient pretreatment ability.

Example 2

In the present embodiment, the COD concentration of the carbon-rich nutrient matrix is 8000 mg/L, and the antibiotic waste water is taken from the comprehensive waste water of an antibiotic pharmaceutical factory, and the ciprofloxacin concentration is 42 mg/L. The specific implementation steps are as follows:

(1) Take the anaerobic activated sludge into the anaerobic bottle, add carbon-rich nutrient substrate and mix with the sludge for domestication. The volume ratio of the sludge to the carbon-rich nutrient substrate is 1:10, and nitrogen is introduced into the anaerobic bottle. 15 minutes to remove oxygen, sealed and acclimated at 37±1°C for 10 hours.

(2) Remove the supernatant, take the lower layer of sludge and mix it with the above-mentioned antibiotic wastewater at a volume ratio of 1:15, and add zero-valent nano-iron and granular activated carbon (iron volatile solid mass ratio of 1:1) to the sludge. carbon ratio 1:1). Nitrogen was introduced into the anaerobic reactor for 15 minutes to remove oxygen, sealed and then placed in 37±1°C, 120r/min for anaerobic acid production and fermentation for 8 hours.

Measure the influent and effluent, the removal rate of ciprofloxacin reaches 93%, and the removal rate of COD reaches 20%. Therefore, the invention has good removal efficiency for high-concentration ciprofloxacin antibiotic wastewater, and can remove part of COD at the same time.

Example 3

In this example, the COD of the carbon-rich nutrient matrix is 5000 mg/L, the antibiotic wastewater is taken from the laboratory water distribution, and the concentration of enrofloxacin is 30 mg/L. The method of using iron-carbon micro-electrolysis coupled with anaerobic acid-producing fermentation process, the specific steps are as follows:

(1) Take the anaerobic activated sludge into the anaerobic bottle, add the carbon-rich nutrient substrate and mix with the sludge for domestication. The volume ratio of the anaerobic activated sludge to the carbon-rich nutrient substrate is 1:15. Bubble nitrogen for 15 minutes to remove oxygen, seal and acclimate at 37±1°C for 12 hours.

(2) Remove the supernatant, take the lower layer of sludge and mix it with the above enrofloxacin antibiotic wastewater at a volume ratio of 1:15, and add zero-valent nano-iron and particles with a mass ratio of 1:1 to the volatile solids of the sludge. Activated carbon (iron to carbon ratio 1:1). Introduce nitrogen into the anaerobic reactor for 15 minutes to remove oxygen, seal it and place it in 37±1℃, 120r/min for anaerobic acid production and fermentation for 7 hours.

Determination of influent and effluent, enrofloxacin removal rate reached 90%, COD removal rate reached 22%.

Claims (9)

1. A method of iron-carbon micro-electrolysis coupling anaerobic acid-producing fermentation process for pretreatment of high-concentration fluoroquinolone antibiotic waste water, comprising the following steps: (1) Anaerobic activated sludge with normal performance index and pH of 7.0~8.0, anaerobic activated sludge and carbon-rich nutrient substrate are mixed in proportion for domestication; (2) Introduce high-purity nitrogen to ensure that the reaction system is in an anaerobic state; (3) Discharge the supernatant after natural precipitation, and retain the lower sludge, which is the anaerobic acid production stage sludge with the required pH of 4.0~5.5; (4), take the anaerobic acid production stage sludge in step 3 and mix it with high-concentration fluoroquinolone antibiotic wastewater; (5) Add zero-valent nano-iron and granular activated carbon to the mixture in step 4, that is, an iron-carbon mixture; (6) Pour high-purity nitrogen into the mixture in step 5 to ensure that the reaction system is in an anaerobic state. 2. iron-carbon micro-electrolysis coupling anaerobic acid-producing fermentation process as claimed in claim 1 is used for the method for pretreatment of high-concentration fluoroquinolone antibiotic waste water, it is characterized in that in step 1, carbon-enriched nutrient matrix COD concentration is 5000～8000mg /L. 3. iron-carbon micro-electrolysis coupling anaerobic acid-producing fermentation process as claimed in claim 1 is used for the method for pretreatment of high-concentration fluoroquinolone antibiotic waste water, it is characterized in that in step 1, carbon-rich nutrient substrate and sludge volume ratio are: 10:1~15:1. 4. the iron-carbon micro-electrolysis coupling anaerobic acid-producing fermentation process as claimed in claim 1 is used for the method for pretreatment of high-concentration fluoroquinolone antibiotic waste water, it is characterized in that in step 2, reaction temperature is 37 ± 1 ℃, reaction The time is 10~12 hours. 5. iron-carbon micro-electrolysis coupled anaerobic acid production fermentation process as claimed in claim 1 is used for the method for pretreatment of high concentration fluoroquinolone antibiotic waste water, it is characterized in that waste water and anaerobic acid production stage sludge in step 4 The volume ratio is 15:1~20:1. 6. iron-carbon micro-electrolysis coupling anaerobic acid production fermentation process as claimed in claim 1 is used for the method for pretreatment of high concentration fluoroquinolone antibiotic waste water, it is characterized in that in step 5, zero-valent nano-iron and granular activated carbon quality The ratio is 1:1. 7. iron-carbon micro-electrolysis coupled anaerobic acid-producing fermentation process as claimed in claim 1 is used for the method for pretreatment of high-concentration fluoroquinolone antibiotic waste water, it is characterized in that in step 5, iron-carbon mixture and anaerobic acid production stage polluted water. The volatile solid mass ratio of the mud is 1:1~1.5:1. 8. iron-carbon micro-electrolysis coupling anaerobic acid-producing fermentation process as claimed in claim 1 is used for the method for pretreatment of high-concentration fluoroquinolone antibiotic waste water, it is characterized in that the reaction temperature of step 6 is 37 ± 1 ℃, reaction The time is 6~8 hours. 9. The method for the pretreatment of high-concentration fluoroquinolone antibiotic wastewater by the iron-carbon micro-electrolysis coupled anaerobic acid-producing fermentation process as claimed in claim 1, wherein the fluoroquinolone antibiotic especially refers to ciprofloxacin.