Biological agent with scale inhibition effect and application thereof

Abstract

The invention provides a biological agent with a scale inhibition effect. The biological agent comprises plant lactobacillus, pseudomonas and a saccharomyces cerevisiae strain. The biological scale inhibitor is a mixture of independent fermentation broth containing the three bacteria, the three bacteria are compounded according to different proportions, and the static scale inhibition effect is tested. The preparation is applied to 10L and 100L circulating water simulation systems, the microbial agent is added according to the proportion that the microbial agent is added every 7 days and the total amount of the microbial agent added each time accounts for 0.01%-0.05% of the circulating water, and compared with a control group, an experimental group added with the biological scale inhibitor shows better scale inhibition and algae inhibition effects within four weeks. The microbial agent disclosed by the invention is applied to a 2800m < 3 > circulating water cooling system for a scale inhibition test, and shows a stable scale inhibition effect compared with a conventional chemical scale inhibitor in a test period of 30 days.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial microbial screening and application, and specifically relates to a biological bacterial agent with scale inhibition effect and application thereof. Background Art

[0002] During the operation of the circulating cooling water system, scaling, corrosion, and microbial growth will occur due to the continuous evaporation and concentration of cooling water and changes in water quality and quantity, which will affect the efficiency and safety of industrial production. At the same time, the circulating water system needs to maintain the concentration ratio at a certain level to achieve the purpose of water conservation, but a high concentration ratio means that the system is more prone to the above problems.

[0003] At present, the most widely used circulating cooling water treatment method is to continuously add a series of organic and inorganic chemical agents such as bactericides, corrosion inhibitors and scale inhibitors to the circulating water system. More than 90% of the formula contains various phosphorus components. The excessive discharge of phosphorus-containing circulating water leads to eutrophication of rivers, lakes and seas, and the proliferation of red tides and blue algae, which seriously damages the ecological environment. In addition, chemical agents also have secondary pollution problems such as limited effect in treating COD / ammonia nitrogen, toxic residues, and inability to degrade naturally.

[0004] Microbial fermentation scale inhibitors are metabolites with scale inhibition function produced by microbial fermentation. The biological macromolecules that play the main role have good biodegradability. Compared with chemical agents, biological scale inhibitors are a type of agent that can disperse insoluble inorganic salts in water, prevent or interfere with the precipitation and scaling of insoluble inorganic salts on the metal surface, and maintain good heat transfer effect of metal equipment. It has the advantages of fast speed, low consumption, high efficiency, mild reaction conditions, and no secondary pollution. Its final products are non-toxic, harmless, and stable substances, such as carbon dioxide, water, nitrogen, etc., which can reduce the phosphorus content in circulating cooling water and avoid eutrophication of water bodies caused by the use of traditional phosphorus-containing scale inhibitors. Summary of the invention

[0005] The purpose of the present invention is to provide a biological bacterial agent with anti-scaling effect and its application, that is, a microbial flora that can be used for anti-scaling and algae inhibition in a circulating water system.

[0006] The biological bacterial agent with anti-scaling effect provided by the present invention comprises plant lactobacillus, pseudomonas and saccharomyces cerevisiae strains;

[0007] As a specific record of the embodiment, the plant lactobacillus is Lactobacillus plantarum PM-5 strain, which was deposited at the General Microbiological Center of China National Microbiological Culture Collection Committee at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing on March 14, 2023, with a deposit number of CGMCC No. 26804;

[0008] As a specific record of the embodiment, the Pseudomonas is Pseudomonas vancouverensis JN-38 strain, which was deposited on March 14, 2023 at the General Microbiology Center of China Culture Collection Administration (No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing), with a deposit number of CGMCC No. 26803.

[0009] Furthermore, the quantitative ratio of Lactobacillus plantarum, Pseudomonas and Saccharomyces cerevisiae is 15:3:2.

[0010] Furthermore, the composition ratio of the culture medium for culturing plant lactobacillus is as follows:

[0011] K2HPO4 0.5g, triammonium citrate 2.0g, anhydrous sodium acetate 5g, MnSO4·7H2O 0.25g, MgSO4·7H2O 0.58g, glucose 20g, peptone 10g, yeast powder 5g, Tween-80 1mL, pH adjusted to 6.2-6.4.

[0012] The composition ratio of the medium for culturing Pseudomonas is as follows:

[0013] 3g beef extract, 5g peptone, 5g NaCl, adjust pH to 7.4-7.6.

[0014] The present invention also provides a use of the biological bacterial agent, which is use in descaling water.

[0015] Another use of the biological bacterial agent described in the present invention is in the preparation of water scale inhibitors.

[0016] The biological scale inhibitor of the present invention is a mixture of separate fermentation broths containing the above three bacteria. The three bacterial broths are compounded in different proportions, and the static scale inhibition effect is tested. Under the condition that PM-5, JN-38 and Saccharomyces cerevisiae are compounded in 75%:15%:10%, a higher static scale inhibition effect is obtained. The above preparation is used in 10L and 100L circulating water simulation systems, and the bacterial agent is added at intervals of 7 days. The total amount of the bacterial agent added each time accounts for 0.01%-0.05% of the circulating water. Compared with the control group, the experimental group with the addition of the biological scale inhibitor showed better scale inhibition and algae inhibition effects within 4 weeks of operation. The bacterial agent of the present invention was applied to 2800m 3 A scale inhibition test was carried out on a circulating water cooling system of a large scale plant. During the 30-day test period, the scale inhibition effect was stable compared with the previous chemical antiscalants. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 :Static scale inhibition rate diagram of bacterial agent,

[0018] Figure 2 : Static scale inhibition effect diagram of three strains combined in different proportions,

[0019] Figure 3 : 10L circulating water dynamic simulation device diagram,

[0020] Figure 4 : 100L circulating water dynamic simulation device diagram,

[0021] Figure 5 :10L circulating water dynamic simulation device scale inhibition rate diagram,

[0022] Figure 6 : Scale inhibition rate diagram of 100L circulating water dynamic simulation device,

[0023] Figure 7 : Comparison of scaling phenomena in the system cooling device,

[0024] Figure 8 : pH change diagram of 100L dynamic circulating water system,

[0025] Fig. 9 :The anti-algae effect diagram of the bacterial agent. DETAILED DESCRIPTION

[0026] The Lactobacillus plantarum PM-5 strain used in the present invention was deposited at the General Microbiology Center of China National Microbiological Culture Collection Committee at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing on March 14, 2023, with a deposit number of CGMCC No. 26804. It was isolated from a kimchi sample and is a facultative anaerobic bacterium that can produce lactic acid. The fermentation pH can reach 4.43, providing a mild organic acid product that acts on the system to maintain a low pH, reduce the system alkalinity, and prevent system scaling.

[0027] The Pseudomonas vancouverensis JN-38 strain used in the present invention was deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration (No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing) on ​​March 14, 2023, with a deposit number of CGMCC No. 26803. JN-38 was isolated from a soil sample in Ji County and can produce carbonic anhydrase with an enzyme activity of 0.270 WAU. Carbonic anhydrase can catalyze the hydration reaction of CO2, namely: The hydration reaction produces H + It will affect the ionization balance of CaCO3 and drive the dissolution of carbonates, namely: Carbonic anhydrase can also maintain the acid-base balance in the environment through the above process.

[0028] The Saccharomyces cerevisiae used in the embodiments of the present invention was purchased from the EUROSCARF online store, website www.euroscarf.de. The Saccharomyces cerevisiae is a type of Saccharomyces cerevisiae, and its main function is to inhibit pathogenic bacteria in the bottom mud of the circulating water system.

[0029] The present invention is described in detail below in conjunction with embodiments and drawings.

[0030] Example 1: Testing the scale inhibition activity of three bacterial strains

[0031] In order to make the scale inhibition effect more stable and further improve the scale inhibition effect, a compatibility test was conducted between three strains: Lactobacillus argentoratensis PM-5 strain with a preservation number of CGMCC No. 26804, Pseudomonas vancouverensis JN-38 strain with a preservation number of CGMCC No. 26803, and Saccharomyces cerevisiae. According to the acid production and carbonic anhydrase production activities of the screened strains, different strains were formed into three combinations, and the scale inhibition was tested under the same conditions with single bacteria with better scale inhibition performance using the calcium carbonate precipitation method. Each single strain or combination was set up with 3 parallels. The scale inhibition performance of the strain was determined with reference to the calcium carbonate precipitation method GB / T 16632-2019.

[0032] The test solution is prepared with actual working water or prepared water containing a certain amount of bicarbonate and calcium ions and water treatment agent. Under heating conditions, calcium bicarbonate is accelerated to decompose into calcium carbonate. After reaching equilibrium, the calcium ion concentration in the test solution is measured. The higher the calcium ion concentration, the better the scale inhibition performance of the water treatment agent.

[0033]

[0034] ρ—calcium ion concentration in the experimental group solution after the experiment, mg / mL; ρ1—calcium ion concentration in the control group solution after the experiment, mg / mL; ρ0—calcium ion concentration in the solution prepared before the experiment, mg / mL.

[0035] Preparation of sodium bicarbonate standard solution: 1 mL contains approximately 18.3 mg HCO3 - , prepare according to the following steps (calibration required): weigh 25.2g of sodium bicarbonate and place it in a 100mL beaker, dissolve it in water, transfer all to a 1000mL volumetric flask, dilute to the mark with water, and shake well. The solution is prepared before use.

[0036] Calcium chloride standard solution: 1 mL contains approximately 6.0 mg Ca 2+ , prepare according to the following steps: weigh 16.7g of anhydrous calcium chloride and place it in a 100mL beaker, dissolve it in water, transfer all to a 1000mL volumetric flask, dilute to the scale with water, and shake well.

[0037] The specific experimental methods are as follows:

[0038] Experimental group: Add 250 mL of water, 10 mL of calcium chloride standard solution, 2 mL of bacterial solution (the pH of the bacterial solution was adjusted to neutral), and 10 mL of sodium bicarbonate standard solution into a 500 mL volumetric flask.

[0039] Preparation of blank test solution: In another 500 mL volumetric flask, repeat the above steps except adding no bacterial solution.

[0040] Place the test solution and blank test solution in two clean conical bottles, or metal containers (for easy observation of scale), keep them at 50℃ for 20 hours, and filter them with medium-speed qualitative filter paper while they are still hot. After cooling, measure the calcium ion concentration and calculate the scale inhibition rate Ω.

[0041] The scale inhibition performance test included 7 strains and 3 combinations, as shown in the following table.

[0042] Table 1: Types and composition of test strains and microbial agents

[0043]

[0044]

[0045] The test results are as follows Figure 1 As shown. From the results, it can be seen that among the 10 strains and combinations, the three groups with the highest static scale inhibition rates are combination 3, combination 2 and strain JXTY-46, with scale inhibition rates of 115%, 106% and 99% respectively. Among them, combination 3 is: 45% PM-5 bacteria, 45% JN-38 bacteria, and 10% Saccharomyces cerevisiae bacteria. The scale inhibition rate of this combination is the highest among all groups, showing the selected strain group and good scale inhibition potential.

[0046] Example 2: Optimization of fermentation broth components of three bacterial strains

[0047] In order to obtain the optimal combination of three bacteria for anti-scaling effect, the culture medium of the three bacteria was improved, and the improved culture medium formula was as follows:

[0048] 1) Modified MRS medium (for culturing PM-5) (1000 mL): K2HPO4 0.5 g, triammonium citrate 2.0 g, anhydrous sodium acetate 5 g, MnSO4·7H2O 0.25 g, MgSO4·7H2O0.58 g, glucose 20 g, peptone 10 g, yeast powder 5 g, Tween-80 1 mL, pH adjusted to 6.2-6.4, sterilization temperature 115°C, 30 min.

[0049] 2) Improved beef extract medium (for culturing JN-38 bacteria) (1000 mL): 3 g beef extract, 5 g peptone, 5 g NaCl, pH adjusted to 7.4-7.6.

[0050] 3) Modified YPD medium (for culturing Saccharomyces cerevisiae) (1000 ml): 10 g Yeast Extract, 10 g Peptone in 900 mL water, 20 g glucose in 100 mL water (sterilized at 115°C for 15 min respectively).

[0051] PM-5 was cultured in modified MRS medium at 37°C for 36 hours, and the OD reached 3.6 and the pH reached 4.43. JN-38 was cultured in modified beef extract medium at 180 rpm and 30°C for 36 hours, and the OD reached 2.3 and the pH reached 8.72. Saccharomyces cerevisiae was cultured in modified YPD medium at 180 rpm and 30°C for 36 hours, and the OD reached 3.604 and the pH reached 8.79.

[0052] The above-cultured seed liquid PM-5, JN-38 and Saccharomyces cerevisiae were combined in different proportions to test their static scale inhibition rate. The strain ratios were combined according to Table 2. The results showed that when PM-5, JN-38 and Saccharomyces cerevisiae were combined in a ratio of 75%:15%:10%, the scale inhibition effect was the best, as shown in Table 2. Figure 2 This shows that increasing the proportion of PM-5 in the combination will help the bacteria to exert their anti-scaling effect.

[0053] Table 2: Numerical table of the proportion of addition in each experimental group

[0054]

[0055]

[0056] Example 3: Testing the scale inhibition effect of biological agents on a simulated circulating water dynamic system

[0057] The scale inhibition effect of combination 3 was tested on 10L and 100L circulating water dynamic systems respectively. The 10L simulation device includes a spray cooling tower, a water storage tank (where bacteria are added), a heating device (water bath), and a peristaltic pump (to provide water circulation power). Figure 3 The 100L simulation device is a QYDM intelligent dynamic simulation test device ( Figure 4 ), the maximum flow of circulating water is 180L / h, and the effective volume of the circulating water tank is 100L. The operating conditions and parameter control of the two systems are as follows:

[0058] 1) Make-up water: tap water is used as make-up water for the circulating water simulation system, and calcium bicarbonate is added. The added calcium bicarbonate contributes 100 mg / L of calcium hardness.

[0059] Tap water contributes about 100 mg / L of calcium hardness, and the additional calcium chloride and sodium bicarbonate solutions contribute 100 mg / L of calcium hardness, making the initial calcium hardness of the circulating water about 200 mg / L.

[0060] 2) System water replenishment: During the operation of circulating water, the water replenishment valve can continuously replenish water at a small flow rate. The amount of water replenishment is the sum of the evaporated water and the sewage discharge.

[0061] 3) Addition of microbial agents: Combination 3 (PAO 45%, J38 45%, Yeast 10%), the first addition is 0.4% of the system water retention capacity, and then 0.1% every 5 days.

[0062] The results showed that after the 10L circulating water dynamic simulation device was operated for 10 days, the bacteria-added group showed a higher scale inhibition rate than the control group ( Figure 5 ). At the end of the experiment, the ammonia nitrogen concentration of the experimental group was 0.45mg / L and the COD was 34mg / L. The 100L circulating water dynamic simulation device was operated for 20 days. At the end of the experiment, the scaling of the experimental group was not obvious (the control group had some scaling), and there was no obvious algae growth. The main manifestations are:

[0063] 1) The scale inhibition rate of the bacteria-added group was significantly higher than that of the control group ( Figure 6 ), the closer the scale inhibition rate is to 1, the less scaling there is. This result shows that adding biological agents can help improve the calcium stability of the system and reduce scaling. From the overall sensory observation, the scaling phenomenon of system 1 is less than that of system 2 ( Figure 7 ), which is consistent with the result of scale inhibition rate.

[0064] 2) The pH of the system with added biological agents is lower than that of the control system ( Figure 8 ), indicating that the biological agent of the present invention improves the stability of scaling ions in water by increasing the solubility of calcium ions, carbonate ions, and bicarbonate ions in water, thereby reducing scaling. This result confirms that the biological agent mainly works through the above-mentioned pathway.

[0065] 3) The algae produced by the group without bacteria were more obvious in both quantity and color than those produced by the group with bacteria ( Fig. 9 ), which shows that adding bacteria has a significant effect on inhibiting algae.

[0066] 4) The developed bacterial agent has good COD reduction and nitrogen removal functions, and can maintain the COD and ammonia nitrogen concentrations of the system at a relatively stable level. The ammonia nitrogen concentration in the experimental group was 61.3% lower than that in the control group, and the COD concentration in the experimental group was 24% lower than that in the control group. The microbial agent can maintain the carbon, nitrogen and phosphorus balance of the circulating water system through its own metabolic cycle, and achieve the function of purifying water and inhibiting algae without introducing toxic chemicals. This is a feature and advantage that is different from the common chemical reagents on the market.

Claims

1. A biological agent with anti-scaling effect, characterized in that: The biological bacterial agent contains plant lactobacillus, pseudomonas and saccharomyces cerevisiae strains.

2. The biological agent according to claim 1, characterized in that: The deposit number of the plant lactobacillus is CGMCC No.26804.

3. The biological agent according to claim 1, characterized in that: The Pseudomonas is Pseudomonas vancouverensis, and its deposit number is CGMCC No.26803.

4. The biological agent according to claim 1, characterized in that: The quantity ratio of plant lactobacillus, pseudomonas and brewer's yeast is 15:3:

2.

5. The biological agent according to claim 1, characterized in that: The composition ratio of the culture medium of the plant lactobacillus is as follows: K2HPO4 0.5g, triammonium citrate 2.0g, anhydrous sodium acetate 5g, MnSO4·7H2O 0.25g, MgSO4·7H2O0.58g, glucose 20g, peptone 10g, yeast powder 5g, Tween-80 1mL, pH adjusted to 6.2-6.

4.

6. The biological agent according to claim 1, characterized in that: The composition ratio of the culture medium for culturing Pseudomonas is as follows: 3g beef extract, 5g peptone, 5g NaCl, adjust pH to 7.4-7.

6.

7. Use of the biological agent according to claim 1 in water descaling.

8. Use of the biological agent according to claim 1 in the preparation of water scale inhibitor.

9. A water antiscalant, characterized in that: The water antiscalant contains the biological bacterial agent according to claim 1.

10. A method for preventing scale in water, characterized in that: The method described is to use the biological bacterial agent described in claim 1 to treat scale.

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