A method of inhibiting the viscous bulking of biochemical sludge
By adding dielectric Rhodococcus and caprolactone to the biochemical system and using lactonase to degrade acylhomoserine lactone, the problem of sludge viscosity and swelling was solved, the sludge settling performance was improved, and the stable operation of the biochemical system was achieved.
Patent Information
- Application Number
- CN202310074884.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-01-19
- Publication Date
- 2025-10-14
- Estimated Expiration
- 2043-01-19
AI Technical Summary
The viscous expansion of sludge leads to loose sludge structure, poor sedimentation and compression performance, increased SV value, serious sludge loss, turbid effluent, and difficulty in maintaining normal operation of biochemical treatment. Existing treatment methods are costly and ineffective.
Adding dielectric Rhodococcus and caprolactone to the biochemical system, the lactonase secreted by the dielectric Rhodococcus degrades the acylhomoserine lactone that causes viscosity and swelling, thereby improving the sedimentation performance of the sludge and making the sludge particles firm.
Significantly reduce SVI value, improve sludge settling performance, prevent sludge loss, ensure the stable operation of the biochemical system, simple operation and low cost.
Smart Images
Figure CN116002850B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of wastewater treatment, and in particular to a method for inhibiting viscous swelling of sludge. Background Art
[0002] Sewage treatment plant enterprises are involved in the production of various types of chemical products such as chemical raw materials, pharmaceutical and pesticide intermediates, anthraquinone dyes, etc. The product composition is complex, and the sewage water quality and water volume fluctuate greatly, which has a great impact on the biochemical system of the sewage treatment plant and is prone to sludge viscosity expansion problems.
[0003] The main characteristics of viscous sludge bulking are: 1) loose sludge structure, reduced mass, and poor sedimentation and compression performance; 2) increased SV values, sometimes reaching 90% and SVI values exceeding 300; 3) significant sludge loss and turbid effluent; 4) difficulty in solid-liquid separation during secondary sedimentation, resulting in low return sludge concentrations and, sometimes, the generation of large amounts of foam, making it impossible to maintain proper biochemical treatment. Once it occurs, it is difficult to control and typically requires a long time to correct. The incidence of viscous sludge bulking is quite high, with nearly 50% of municipal wastewater treatment plants experiencing varying degrees of viscous sludge bulking annually.
[0004] There are two main types of sludge bulking: 1) Viscous bulking of filamentous sludge caused by excessive growth of filamentous bacteria in activated sludge; 2) Viscous bulking of non-filamentous bacteria caused by the accumulation of high-viscosity substances in bacterial flocs or the invasion of activated sludge by toxic substances.
[0005] At present, the main methods for treating viscous expansion of activated sludge are as follows: 1) Enhanced aeration; 2) Adjustment of load; 3) Staged water injection; 4) Addition of nitrogen-containing compounds; 5) Addition of lime and digested sludge (increase the sludge specific gravity); 6) Dilution of influent sewage; 7) If the carbohydrate content increases, the source of the wastewater should be investigated; 8) When toxic wastewater enters the system, it should be pretreated; 9) Inoculation of activated sludge.
[0006] It is necessary for us to make improvements based on the existing technology to achieve the purpose of conveniently, more effectively and more cheaply inhibiting the viscous expansion of activated sludge and improving the efficiency of sewage treatment. Summary of the Invention
[0007] The present invention primarily addresses the following issues: Currently, activated sludge settling performance deteriorates, SVI and SV values continue to increase, and the MLSS concentration in the aeration tank continues to decrease, resulting in loose sludge flocs, sludge loss, and turbid effluent. The present invention provides a convenient and low-cost method for inhibiting the viscous expansion of biochemical activated sludge, namely, 1) a certain proportion of dielectric Rhodococcus is compounded into the biochemical sludge to inhibit the viscous expansion of the sludge; and 2) caprolactone is added to the biochemical sludge containing dielectric Rhodococcus, which has a more significant inhibitory effect on the viscous expansion of the biochemical sludge. The present invention improves the compactability of the sludge and improves the settling performance of the sludge. The improved settling performance makes the sludge particles more compact and less likely to be lost.
[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:
[0009] A method for inhibiting viscous swelling in activated sludge involves adding dielectric Rhodococcus bacteria to a biochemical system to improve the settling performance of the activated sludge. The method involves adding a dielectric Rhodococcus bacterial solution to the biochemical system in a single dose at a rate of 0.5% to 5% of the sludge concentration. The preferred addition rate is 5% of the sludge concentration.
[0010] A method for significantly inhibiting viscous bulking of activated sludge involves adding a certain concentration of caprolactone and dielectric Rhodococcus to a biochemical system to improve the settling performance of the activated sludge. The specific method is as follows: 1) A dielectric Rhodococcus bacterial solution and caprolactone are added to the biochemical system in a single dose, with the dielectric Rhodococcus solution added at a concentration of 0.5-3 mg / L; 2) Caprolactone is added to the biochemical system every 1-5 days, repeated 1-5 times, depending on the sludge bulking condition, at a concentration of 0.5-3 mg / L. The dielectric Rhodococcus solution is preferably added at a concentration of 0.5-5% of the sludge concentration, and the caprolactone concentration is preferably 3 mg / L. Caprolactone is preferably added to the biochemical system every three days.
[0011] Depending on the sludge bulking condition, if the effect persists, the interval can be extended until caprolactone addition is no longer required.
[0012] Caprolactone is added to the biochemical system to a concentration within the range of 0.5-3 mg / L, preferably 3 mg / L.
[0013] The dielectric rhodococcus is dielectric rhodococcus ( Rhodococcus electrodiphilus )TN-3, which is classified as bielectric Rhodococcus ( Rhodococcus electrodiphilusTN-3, deposited with the China Center for Microbiological Culture Collection, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, on November 19, 2021, under the accession number CGMCC No. 23936. Physiological characteristics include rough or smooth, even mucous, colonies resembling mycobacteria. This aerobic, heterotrophic bacterium is Gram-positive. Clear colonies develop on solid agar plates after 24 hours of incubation. These colonies are round or oval, with neat, opaque edges and appear red under moist natural light.
[0014] The lactonase secreted by Rhodococcus dielectricus TN-3 degrades the acylhomoserine lactone on the surface of the activated sludge that causes viscous swelling, thereby inhibiting the viscous swelling of the activated sludge. Caprolactone can also promote the secretion of more lactonase by Rhodococcus dielectricus, which has a more significant effect in inhibiting the viscous swelling of the activated sludge, reducing the SVI value of the activated sludge, improving sedimentation performance, and making the sludge particles more solid and less likely to be lost, ensuring the long-term stability and normal operation of the biochemical system.
[0015] The double-electric Rhodococcus bacterial solution is prepared by the following method:
[0016] The strain culture of Rhodococcus selectrodiphilus TN-3 includes the steps of activation, transfer and expansion.
[0017] 1) Activation: Pick a single colony from the solid plate and transfer it to LB liquid medium. Incubate at 35-38°C with a shaker at 130-180 rpm for 3-4 hours until the cells reach the logarithmic phase.
[0018] 2) Transfer: Transfer the bacterial solution in the logarithmic phase to a seed tank for culture. Maintain the temperature of the seed tank at 25-30°C, the rotation speed at 220-250 rpm, and the dissolved oxygen (DO) at 2.5-3 mg / L for 24-48 hours.
[0019] 3) Expansion culture: Transfer the bacterial liquid cultured in the seed tank to the fermentation tank according to the inoculation volume of 2%-5% for expansion culture. The composition of the fermentation tank culture medium is the same as that of the seed tank. The physical and chemical parameters are as follows: temperature 25-30℃, rotation speed 220-250rpm, dissolved oxygen 2.5-3 mg / L, and fermentation time 48h-60h.
[0020] The LB liquid culture medium components include: 3 g / L beef extract, 10 g / L peptone, 5 g / L sodium chloride, and the pH is maintained between 7.2 and 7.5.
[0021] The culture medium components of the seed tank are: beef extract 3g / L, peptone 10g / L, sodium chloride 5g / L, potassium nitrate 3g / L, glucose 3.6g / L, potassium dihydrogen phosphate 0.2g / L, magnesium sulfate heptahydrate 0.2g / L, calcium carbonate 2g, trace element solution 1mL / L (zinc chloride 80mg, anhydrous copper sulfate 20mg, boric acid 20mg, ferrous sulfate heptahydrate 100mg), water 1000mL, pH 7-7.5.
[0022] After the strain is cultured, the effective viable bacteria count in the bacterial solution can reach 10 9 After the fermentation culture liquid is taken out of the tank and packaged, a concentrated solution of double-electric Rhodococcus with a bacterial concentration of 20% can be obtained. Beneficial effects
[0023] The lactonase secreted by Rhodococcus dielectricus degrades the acyl homoserine lactone on the surface of activated sludge that causes sticky swelling, thereby inhibiting the sticky swelling of activated sludge;
[0024] Caprolactone can also promote the secretion of more lactonase by Rhodococcus dielectricus, which has a more obvious effect in inhibiting the viscous expansion of activated sludge, reducing the SVI value of activated sludge, improving sedimentation performance, making the sludge particles more solid and less likely to be lost, thus ensuring the long-term stability and normal operation of the biochemical system;
[0025] The operation is simpler, the cost is lower and the effect is better. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 Dyeing diagram of activated sludge after viscous expansion;
[0027] Figure 2 This is the staining picture after adding double-electrophoretic Rhodococcus to the viscous expanded sludge;
[0028] Figure 3 The graph is a comparison of sticky bulking sludge, sticky bulking sludge with the addition of dielectric Rhodococcus, and sticky bulking sludge with the addition of caprolactone and dielectric Rhodococcus;
[0029] Figure 4 The SVI changes of viscous and expanded activated sludge after adding different amounts of dielectric Rhodococcus;
[0030] Figure 5 Changes in SVI of viscous and expanded activated sludge after adding dielectric Rhodococcus and caprolactone. DETAILED DESCRIPTION
[0031] The following specific embodiments further describe the application of the present invention, but are not intended to limit the scope of the present invention. Without departing from the spirit and essence of the present invention, modifications or replacements made to the method, steps or conditions of the present invention are within the scope of the present invention.
[0032] The sludge that underwent viscous expansion in this experiment came from the sewage treatment station of a pharmaceutical factory in Taizhou, Jiangsu. Example 1
[0033] Viscous, expanded biochemical sludge was micro-aerated at the bottom of the aeration tank using a microbubble generator at a flow rate of 32 L / min. After aeration for 3 hours, the sludge was allowed to rest for 1.5 hours. After treatment, the SVI value was 230 mL / g. Example 2
[0034] The double-electric Rhodococcus bacterial solution is prepared by the following method:
[0035] The culture of Rhodococcus selectrodiphilus TN-3 includes the following steps: activation, transfer, and expansion:
[0036] 1) Activation: Pick a single colony from the solid plate and transfer it to LB liquid medium. Incubate at 37°C with a shaker at 150 rpm until the logarithmic phase.
[0037] 2) Transfer: Transfer the bacterial solution in the logarithmic phase to a seed tank for culture. Maintain the temperature of the seed tank at 28°C, the rotation speed at 250 rpm, and the dissolved oxygen (DO) at 2.5-3 mg / L for 24-48 hours.
[0038] 3) Expansion: Transfer the bacterial solution cultured in the seed tank to the fermentation tank at a 5% inoculum volume for expansion. The composition of the fermentation tank medium is the same as that of the seed tank. The physicochemical parameters are as follows: temperature 28°C, rotation speed 250 rpm, dissolved oxygen 2.5-3 mg / L, and fermentation time 60 h.
[0039] The LB liquid culture medium components include: 3 g / L beef extract, 10 g / L peptone, 5 g / L sodium chloride, and the pH is maintained between 7.2 and 7.5.
[0040] The culture medium components of the seed tank are: beef extract 3g / L, peptone 10g / L, sodium chloride 5g / L, potassium nitrate 3g / L, glucose 3.6g / L, potassium dihydrogen phosphate 0.2g / L, magnesium sulfate heptahydrate 0.2g / L, calcium carbonate 2g, trace element solution 1mL / L (zinc chloride 80mg, anhydrous copper sulfate 20mg, boric acid 20mg, ferrous sulfate heptahydrate 100mg), water 1000mL, pH 7-7.5.
[0041] After the strain is cultured, the effective viable bacteria count in the bacterial solution can reach 10 9 After the fermentation culture liquid is taken out of the tank and packaged, a concentrated solution of double-electric Rhodococcus with a bacterial concentration of 20% can be obtained.
[0042] A Rhodococcus dielectric bacteria solution was added to the biochemical sludge in a one-time dosage of 0.5% of the sludge concentration. A microbubble generator was used to aerate the bottom of the aeration tank at a flow rate of 32 L / min. After aeration for 3 hours, the tank was allowed to stand for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 210 mL / g. Example 3
[0043] A 20% solution of Rhodococcus dielectricus was added to the biochemical sludge in a one-time addition, at a concentration of 1.5% of the sludge concentration. A microbubble generator was used to aerate the bottom of the aeration tank at a flow rate of 32 L / min. After aeration for 3 hours, the tank was allowed to rest for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 195 mL / g. Example 4
[0044] A Rhodococcus dielectric bacteria solution was added to the biochemical sludge in a one-time dosage of 2.5% of the sludge concentration. A microbubble generator was used to aerate the bottom of the aeration tank at a flow rate of 32 L / min. After aeration for 3 hours, the tank was allowed to stand for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 172 mL / g. Example 5
[0045] A Rhodococcus dielectric bacteria solution was added to the biochemical sludge in a one-time dosage of 4% of the sludge concentration. A microbubble generator was used to aerate the bottom of the aeration tank at a flow rate of 32 L / min. After aeration for 3 hours, the tank was allowed to rest for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 168 mL / g. Example 6
[0046] A Rhodococcus dielectric bacteria solution was added to the biochemical sludge in a one-time addition at a rate of 5% of the sludge concentration. A microbubble generator was then used to micro-aerate the bottom of the aeration tank at a flow rate of 32 L / min. After aeration for 3 hours, the tank was allowed to rest for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 160 mL / g. Example 7
[0047] A one-time addition of a Rhodococcus dielectric bacteria solution to the biochemical sludge was performed at 5% of the sludge concentration. Initially, 0.5 mg / L of caprolactone was added to the biochemical system, followed by a 0.5 mg / L addition every three days for a total of four caprolactone additions per hour. A microbubble generator was used to micro-aerate the bottom of the aeration tank at an air flow rate of 32 L / min. After aeration for three hours, the tank was allowed to stand for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 143 mL / g. Example 8
[0048] A Rhodococcus dielectric bacteria solution was added to the biochemical sludge in a one-time dosage of 5% of the sludge concentration. Initially, 1.0 mg / L of caprolactone was added to the biochemical system, followed by a 1.0 mg / L addition every three days, repeated three times. A microbubble generator was used to micro-aerate the bottom of the aeration tank at a flow rate of 32 L / min. After three hours of aeration, the tank was allowed to rest for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 135 mL / g. Example 9
[0049] A Rhodococcus dielectric bacteria solution was added to the biochemical sludge in a one-time dosage of 5% of the sludge concentration. 2.0 mg / L of caprolactone was initially added to the biochemical system, followed by a 2.0 mg / L dose every three days, repeated three times. A microbubble generator was used to micro-aerate the bottom of the aeration tank at a flow rate of 32 L / min. After three hours of aeration, the tank was allowed to rest for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 120 mL / g, and the viscous swelling phenomenon disappeared. Example 10
[0050] A Rhodococcus dielectric bacteria solution was added to the biochemical sludge in a one-time dosage, at a rate of 5% of the sludge concentration. Caprolactone was initially added to the biochemical system to a concentration of 3.0 mg / L, followed by three-day additions. A microbubble generator was used to micro-aerate the bottom of the aeration tank at a flow rate of 32 L / min. After three hours of aeration, the tank was allowed to rest for 1.5 hours. After treatment, the SVI value decreased from 230 mL / g to 87 mL / g, and the viscous swelling phenomenon disappeared.
Claims
1. A method for inhibiting viscous swelling of biochemical sludge, characterized by: Add dielectric Rhodococcus to the biochemical system at a rate of 0.5%-5% of the sludge concentration; The dielectric Rhodococcus is dielectric Rhodococcus TN-3 with a deposit number of CGMCC NO.23936; Caprolactone was added to the biochemical system at the same time as the addition of the dielectric Rhodococcus; The caprolactone addition concentration is 0.5-3 mg / L.
2. The method for inhibiting viscous swelling of biochemical sludge according to claim 1, characterized in that: The addition amount of the dielectric rhodococcus is 5% of the sludge concentration.
3. The method for inhibiting viscous swelling of biochemical sludge according to claim 1, characterized in that: The caprolactone is added every 1-5 days.
4. The method for inhibiting viscous swelling of biochemical sludge according to claim 1, characterized in that: The effective live bacteria count of the double-electric rhodococcus is 10 9 More than 1000 / ml of double-electrococcus bacterial solution.
5. The method for inhibiting viscous swelling of biochemical sludge according to claim 1, characterized in that: The caprolactone addition concentration is 3 mg / L.