CN110683725A - Sludge dewatering method by coupling microbial cracking pretreatment and PAM flocculant chemical flocculation - Google Patents

Abstract

The invention relates to a sludge dewatering method using microbial pretreatment coupled with PAM flocculant for chemical flocculation, and belongs to the technical field of sludge treatment. Aiming at the problems of large dosage of flocculant, high cost, unsatisfactory dewatering effect, and difficulty in subsequent disposal of sludge and secondary pollution in the existing sludge dewatering method, the present invention makes full use of a series of bacteria with phagocytic ability, and It parasitizes and lyses sludge bacterial cells to obtain proteins and other substances required for growth, and prepares such bacteria into phage-type bacterial compound bacteria, which is used in conjunction with PAM to pretreat residual sludge in municipal sewage treatment plants to effectively destroy Sludge structure, improve the sludge dewatering performance, and then use the conventional mechanical dewatering device of the sewage plant to carry out the whole process of sludge dewatering. On the basis of reducing the usage of conventional PAM flocculants by 20-35%, the sludge dewatering performance can be improved by more than 5%. The invention treats the residual sludge of the municipal sewage biological treatment process, improves the dewatering performance of the sludge, reduces the use of chemical agents, reduces the harmful bacteria in the sludge, improves the resource utilization potential of the sludge subsequent disposal, and has good economic and environmental benefits.

Description

Sludge dewatering using microbial lysis pretreatment coupled with chemical flocculation of PAM flocculants method

technical field

The invention relates to a sludge dewatering method, in particular to a sludge dewatering method using microbial cracking pretreatment coupled with PAM flocculant chemical flocculation, and belongs to the technical field of biological technology coupled with chemical technology for sludge treatment.

Background technique

Municipal sewage treatment plants generally use biological methods to purify wastewater, resulting in a large amount of excess sludge with a water content of more than 95%. With the popularization of urban sewage treatment facilities in my country, the improvement of treatment rate and the deepening of treatment degree, the amount of excess sludge produced has grown tremendously. The excess sludge has the characteristics of large output, high moisture content, perishable and odorous, and its treatment and disposal costs are high. Therefore, the effective and safe reduction of sludge is a worldwide problem. At present, the dehydration and weight reduction treatment of sludge in sewage treatment plants generally adopts the method of chemical conditioner combined with high-pressure mechanical filtration, which has high treatment and disposal costs, and the use of some chemical agents, such as quicklime, even increases the quality of de-cemented biscuits and leads to two The existence of secondary pollution risks is not conducive to the subsequent resource treatment of mud cakes, so new technologies for municipal sludge treatment that are economical, environmentally friendly, efficient and practical are urgently needed.

In the sludge dewatering technology, the three methods of plate and frame filter press, belt filter press and centrifugal filter press are widely used. In order to adjust the floc structure of sludge, promote the release of sludge moisture, and improve the efficiency of sludge dewatering, chemical pretreatment is often accompanied by a necessary step before sludge dewatering. At present, chemical pretreatment technology is often matched with dehydration methods. High-pressure dehydration usually uses inorganic coagulants as pretreatment chemicals, and low-pressure dehydration generally uses organic flocculants as pretreatment chemicals. However, it should be pointed out that the flocculant conditioning sludge is mainly a compression process of extracellular polymer (EPS), and part of the water stored in EPS cannot be released, so the removal capacity of bound water is very limited. The difficulty of filtration and dewatering of sludge lies in changing the hydrophilicity of EPS, and destroying its structure is an important link to improve the dewatering performance of sludge. Meanwhile, intracellular bound water accounts for 70%-80% of the total cell mass. The lysis of sludge cells to release intracellular water is the core of effective sludge dewatering and reduction, and the single use of chemical flocculants for conditioning obviously has huge defects.

In addition, chemical flocculants have strong biological resistance. For example, polyacrylamide (PAM) must be added to dehydration using the belt filtration method, but even PAM that has been degraded into small molecules still has the characteristics of strong biological resistance, and its accumulation in the environment, The toxicity brought about by migration and transformation will gradually emerge, which will bring problems such as loss of soil fertility, and will bring immeasurable long-term harm to the ecological environment. Therefore, it is of great significance to use the biological pyrolysis technology of sludge to reduce the amount of chemicals used or even not use chemicals.

There are currently three traditional sludge treatment methods: incineration, landfill and resource utilization. The incineration process is mostly used abroad, but the investment is huge; the landfill is mostly used in China, but it takes up a lot of land. In addition, sludge landfill and resource utilization have encountered problems, because the sludge not only contains a large number of pathogenic bacteria and eggs, but also is difficult to be absorbed by crops, and the fertilizer effect is slow. Therefore, it is necessary to reduce harmful bacteria such as coliforms in sludge.

SUMMARY OF THE INVENTION

Purpose of the invention: The present invention is aimed at the technical and environmental problems existing in the existing sludge dewatering pretreatment using only PAM single chemical flocculant, specifically for the existing sludge dewatering method with large dosage of flocculant, high cost, and high dehydration. The effect is unsatisfactory and will lead to problems such as difficulty in subsequent disposal of sludge and secondary pollution. The present invention provides for the first time a sludge dewatering method using microbial cracking pretreatment coupled with PAM flocculant chemical flocculation. The technical problem to be solved is to provide a sludge dewatering method. The biochemical combined technology of sludge dewatering using microbial pretreatment coupled with PAM flocculant, comprehensively using the principles of microbial cracking, EPS and SMP degradation, combined with PAM chemical flocculant flocculation, etc., to achieve increased sludge dewatering capacity, shortened reaction time, and chemical flocculation. The effect of reducing the amount of agent used and the harmful bacteria in the sludge can be solved, and it can solve the difficulties in the sludge treatment process, the secondary pollution of the factory sludge and the health and safety problems.

Technical solution: In order to solve the above technical problems, the present invention provides a sludge dewatering method using microbial cracking pretreatment coupled with PAM flocculant chemical flocculation, and the method includes the following details:

1) Preparation of the phage-type bacterial compound agent: the live bacteria in the phage-type bacteria compound agent include at least one or more of leech vibrio, leech vibrio stope, and leech vibrio stahl , and/or one or more of yeast flora, Gram-positive actinomycetes, and filamentous flora of fermentation system, one of which has the deposit number of CGMCC No. 11671.

2) Mix the phage-type bacterial compound bacterial agent with the remaining sludge to be treated;

3) PAM flocculant solution preparation;

4) Add the PAM flocculant solution to the sludge after microbial pretreatment for chemical re-flocculation.

As an improvement of the present invention, the concentration range of the phage-type bacterial compound bacterial agent prepared in the step 1) ranges from 10 ⁵ to 10 ¹¹ pfu/mL.

As an improvement of the present invention, the dosage volume of the phage-type bacterial compound bacterial agent in the step 2) is 0.1-1% of the volume of the remaining sludge to be treated.

In order to optimize the movement and lysis of Hirudovibrio, after the phage-type bacterial compound bacterial agent in the step 2) is added to the sludge, continuous aeration is performed to make the dissolved oxygen concentration in the sludge 0.5- 5 mg/L.

As an improvement of the present invention, the concentration mass percentage of the PAM flocculant solution prepared in the step 3) ranges from 1 to 3‰.

As an improvement of the present invention, the dosage of the PAM flocculant solution in the step 4) is 0.5-4 mg/g TSS excess sludge.

As an improvement of the present invention, the agitation in the step 4) is firstly carried out with rapid stirring for 5 to 10 minutes, and the rapid stirring speed is 150 to 250 r/min, and then the conventional stirring is carried out after the rapid stirring. 50r/min.

As an improvement of the present invention, the initial moisture content of the remaining sludge to be treated needs to be controlled at 95-99%.

Bacteriophages such as Hirudovibrio are obligate predatory bacteria that prey on a wide range of Gram-negative bacteria, including many human pathogens such as Escherichia coli. During the "attack phase" of its life cycle it searches for host bacteria through water or soil. Once it collides with the host bacterial cell, Hirudo vibrio attaches to the surface of the prey bacteria, destroys the outer cell membrane, kills the host bacterial cell by stopping its respiration and growth, and burrows into its periplasm. During the "growth phase", Hirudovibrio grows by utilizing the macromolecules of the host bacteria as nutrients and essential components for growth. Once the nutrients that the host bacteria can provide are exhausted, the leech vibrio splits into multiple offspring, which then lyse the remains of the host bacteria and wander off to find new host cells. In nature, leech vibrio is considered an ecologically balanced species. Due to their specific behavior, Hirudovibrio is increasingly used for a wide range of technical applications and scientific research. For example, it can gradually replace existing antibiotics, become biological control agents in animal husbandry, and even serve as tools to improve water purification processes.

The municipal sewage treatment plant uses the activated sludge method to treat domestic sewage, resulting in a large amount of excess sludge. Under the condition of air, the full contact between the leech vibrio and the host bacteria is ensured and the growth of leech vibrio is suitable. The reason for the difficulty of dewatering the excess sludge is mainly due to the protein, polysaccharide and humic acid in the extracellular polymer (EPS) and soluble microbial product (SMP) of the sludge. Sludge mixed liquid suspended solids (MLSS) combine to make the sludge flocs large in size and interact closely with each other, making it difficult to disintegrate and remove part of the water stored in EPS. By adding leech vibrio, along with preying on host cells to achieve proliferation and growth, the lysis process of excess sludge can be effectively carried out. Further research shows that leech vibrio can hydrolyze proteins, carbohydrates, nucleic acids and fatty acids in sludge by secreting extracellular protease, glycanase, etc., and cooperate with its phagocytosis to degrade sludge formed by cell interaction. Cell membrane can effectively control the adhesion of microorganisms and the formation of gel layer, inhibit the production of extracellular polymer (EPS) by sludge cells in excess sludge, make EPS easier to extract and release, and produce a looser sludge floc structure. , greatly reducing the difficulty of subsequent reflocculation with chemical flocculants.

The invention mainly uses biological action principles such as microbial cracking, EPS and SMP degradation, sludge floc structure destruction, etc., coupled with PAM flocculant through adsorption and bridging to rebuild the sludge floc structure and carry out chemical re-flocculation, which is efficient and economical. To achieve the purpose of not only reducing the amount of PAM flocculant, but also ensuring the speed and effect of filtration. At the same time, the chemical re-flocculation function of the coupled PAM flocculant proposed by the present invention can re-establish the sludge floc. Biological cracking and chemical reflocculation synergize with each other to achieve the effect of increasing sludge dewatering capacity, shortening reaction time, reducing the amount of chemical flocculants used, and reducing harmful bacteria in sludge.

Beneficial effects: Compared with the prior art, the advantages of the present invention are as follows: 1) The invention promotes the self-lysis of sludge cells and microorganisms in the excess sludge by adding phage-type bacterial compound bacteria, and realizes the release of intracellular water At the same time, it inhibits the production of EPS by the sludge cells in the excess sludge, making the EPS easier to extract and release, and the resulting sludge floc has a looser structure; 2) The invention re-establishes the biological lysis by coupling the chemical reflocculation of the PAM flocculant. After the sludge flocs, the dehydration rate is increased and the biological reaction time is reduced; 3) This scheme does not need to add enzymes, oxidants, etc., and reduces the dosage of PAM during the sludge treatment process by 20-35%. The harmful bacteria are reduced by 20-40%, and the sludge dewatering performance can be improved by more than 5%. The operation is simple and the problems of environmental ecology and sanitation and safety are significantly reduced; 4) This scheme significantly reduces the amount of sludge discharge, biological reaction time and the frequency of microbial inoculum dosing, reduces the pressure of sludge treatment and disposal, and reduces the cost of sludge treatment and disposal.

Description of drawings

Fig. 1 is a schematic diagram of the time change of sludge capillary water absorption in blank group and experimental group in Example 1;

Fig. 2 is a schematic diagram of time variation of sludge specific resistance in blank group and experimental group in Example 1;

Fig. 3 is a schematic diagram of the time change of sludge capillary water absorption in blank group and experimental group in Example 2;

Fig. 4 is embodiment 3 blank group and experimental Escherichia coli flora number change schematic diagram;

FIG. 5 is a schematic diagram of the time change of sludge capillary water absorption under the action of different leech vibrio in Example 4. FIG.

Detailed ways

In order to enhance the understanding and understanding of the present invention, the present invention will be further described and introduced below in conjunction with the accompanying drawings and specific embodiments.

Example 1

Referring to Figure 1 and Figure 2, this process is used for batch treatment of sludge in the laboratory, and the treated sludge is secondary sedimentation tank sludge produced by the oxidation ditch process for treating municipal sewage.

(1) Preparation of phage-type bacterial compound bacterial agent

Prepare phage-type leech vibrio, stope leech vibrio, stahl leech vibrio in advance as phage-type bacterial compound agents, phage leech vibrio, stope leech vibrio, stahl leech vibrio The mixed concentration is on the order of 10 ⁸ pfu/mL. Among them, the phage-type leech vibrio strain is named SDWB01, which has been deposited in the General Microbiology Center of China Microorganism Culture Collection Management Committee on May 12, 2016, and the preservation number is CGMCC No. 11671.

Leech vibrio stope and leech vibrio Stahl can be routinely screened in the sludge to obtain common strains.

(2) Preparation of PAM flocculant solution

Prepare PAM flocculant solution in advance: choose PAM flocculant from Shandong Nuoer Biotechnology Co., Ltd., the product number is 22800, and the concentration of the PAM flocculant solution is 3‰.

(3) Pretreatment of sludge

After the sludge is naturally settled, the lower layer of sludge is removed. The initial sludge mass concentration needs to be controlled at 23.6 g/L, and there is no need to adjust the sludge pH. The measurement result of the sludge pH is 6.75, and the sludge temperature does not need to be adjusted. ℃, stir the sludge evenly and start to distribute it into 500mL glass bottles, each glass bottle contains 350mL sludge;

(4) Dosing of phage-type bacterial compound bacterial agent;

(5) Chemical reflocculation using PAM flocculant.

The experiment was divided into experimental group and control group.

The sludge of all control and experimental groups was taken from the same batch of pretreated sludge. The lower layer of thick sludge after sedimentation is mixed evenly and then packed into 500mL glass bottles, each bottle is filled with 350mL;

Control group: three 350mL sludges were three parallel samples, 3.5mL ultrapure water was added to the sludge and mixed well;

Experimental group: put the same amount of 350mL mixed uniform sludge into two glass bottles A and B, and add 3.5mL of phage-type bacterial compound bacterial agent respectively to make the mixed concentration reach 10 ⁶ pfu/mL, mix evenly, each glass There are three parallel samples in the bottle.

Both the experimental group and the control group were placed in a shaker at 30 °C and 150 r/min for 12 h, and the dissolved oxygen concentration in the sludge was 4 mg/L.

Then add PAM flocculant at the concentration of 0, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 mg/g TSS for chemical re-flocculation: firstly perform rapid stirring, rapid stirring for 10 minutes, and rapid stirring The speed was 150 r/min, and then the conventional stirring was carried out for 30 minutes after rapid stirring, and the conventional stirring speed was 50 r/min. After the conventional stirring is completed, mix the sludge in the glass bottle and take out 30 mL of sludge, measure the capillary water absorption time of the sludge, take out 150 mL of sludge, and measure the specific resistance of the sludge. The test results are shown in Figures 1 and 2.

(6) Test results:

Sludge specific resistance (SRF) and capillary water absorption time (CST) are used to determine the sludge dewatering performance. The lower the value is, the better the sludge dewatering performance is. When the concentration of bacteria reaches 10 ⁶ pfu/mL, when the concentration of PAM flocculant is 2.0 mg/g TSS, the dehydration performance effect of a single PAM flocculant concentration of 3.0 mg/g TSS can be achieved. 35% reduction, thus it can be proved that the sludge dewatering method of using the microorganism pretreatment coupled with PAM flocculant chemical re-flocculation in the sludge can significantly reduce the demand of PAM chemical flocculant, so as to achieve the purpose of good sludge dewatering performance .

Example 2

Referring to Figure 3, this process is used for batch treatment of sludge in the laboratory, and the treated sludge is the secondary sedimentation tank sludge produced by the MBR membrane bioreactor process for treating municipal sewage.

(1) Preparation of phage-type bacterial compound bacterial agent

Prepare the phage-type bacteria compound bacterial solution in advance, including leech vibrio, yeast flora, and gram-positive actinomycetes. The mixed concentration was on the order of 10 ⁹ pfu/mL. Among them, the Bacteriophage Vibrio strain is named SDWB01, which has been deposited in the General Microbiology Center of China Microorganism Culture Collection Management Committee on May 12, 2016, and the preservation number is CGMCC No. 11671.

Yeast flora and gram-positive actinomycetes use Chengbang microbial flora liquid yeast products (Item No. 20205) and Gram-positive actinomycetes products (Item No. 20201).

(2) Preparation of PAM flocculant solution

Prepare PAM flocculant solution in advance: choose PAM flocculant from Shandong Nuoer Biotechnology Co., Ltd., the product number is 22800, and the concentration of the PAM flocculant solution is 2.5‰.

(3) Pretreatment of sludge

After the sludge is naturally settled, the lower layer of sludge is removed. The initial sludge mass concentration needs to be controlled at 21.5 g/L, no need to adjust the sludge pH, and the measured result of the sludge pH is 7.35, and the sludge temperature does not need to be adjusted, and the sludge temperature is measured to be 25 ℃, stir the sludge evenly and start to distribute it into 500mL glass bottles, each glass bottle contains 350mL sludge;

(4) Dosing of phage-type bacterial compound bacterial agent;

(5) Chemical reflocculation using PAM flocculant.

The experiment was divided into experimental group and control group.

The sludge of all control and experimental groups was taken from the same batch of pretreated sludge. The lower layer of thick sludge after sedimentation is mixed evenly and then packed into 500mL glass bottles, each bottle is filled with 350mL;

Control group: put the same amount of 350mL mixed sludge into the two glass bottles A and B, respectively add 3.5mL of phage-type bacterial compound bacterial agent, and the mixed concentration reaches 10 ⁷ pfu/mL, mix evenly, set three parallel. ;

Experimental group: put the same amount of 350mL mixed sludge into two glass bottles C and D, respectively add 3.5mL of phage-type bacterial compound bacterial agent, and the mixed concentration reaches 10 ⁷ pfu/mL, mix evenly, set three parallel.

All control groups were placed in a shaker at 30°C and 150r/min for 24h.

The experimental group was cultured in a shaker at 30°C and 150r/min for 24h, and the dissolved oxygen concentration in the sludge was 3 mg/L. Then, PAM flocculant was added at a concentration of 1 mg/g TSS, and chemical re-flocculation was carried out: first, rapid stirring, rapid stirring for 5 minutes, rapid stirring speed of 250 r/min, rapid stirring followed by conventional stirring for 30 minutes, conventional stirring The speed is 50r/min.

Every 4 hours after the conventional stirring is completed, the sludge in the glass bottle is mixed and 30 mL of sludge is taken out, and the time of sludge capillary water absorption is measured. The test results are shown in Figure 3.

(6) Test results:

The capillary water absorption time (CST) is used to determine the sludge dewatering performance. The lower the value, the better the sludge dewatering performance. It can be seen from Figure 3 that the concentration of leech vibrio added to the sludge reaches 10 ⁷ pfu/mL. Adding PAM flocculant at a concentration of 1 mg/g TSS can make the microbial pretreatment coupled with PAM flocculant chemical re-flocculation reaction time of 16h to achieve the dewatering performance of the sludge after a single biological cracking reaction for 24h, and the reaction time is reduced by 25 hours. %, it can be proved that the sludge dewatering method using the microorganism pretreatment coupled with PAM flocculant chemical re-flocculation in the sludge can significantly shorten the biological cracking reaction time, so as to achieve the purpose of good sludge dewatering performance. At the same time, when the reaction time reached 24h, the sludge dewatering method using microbial pretreatment coupled with PAM flocculant chemical re-flocculation was improved by 14.6% compared with the single PAM chemical flocculation treatment of sludge.

Example 3

Referring to Figure 4, this process is used for batch treatment of sludge in the laboratory, and the treated sludge is the secondary sedimentation tank sludge produced by the A2/O process for treating municipal sewage.

(1) Preparation of phage-type bacterial compound bacterial agent

Prepare in advance phage Vibrio phage, Gram-positive actinomycetes, and filamentous flora of fermentation system as a phage-type bacterial compound bacterial solution, among which leech vibrio and Gram-positive actinomycetes The mixed concentration of the filamentous flora of the fermentation system was in the order of 10 ⁶ pfu/mL. Among them, the Bacteriophage Vibrio strain is named SDWB01, which has been deposited in the General Microbiology Center of China Microorganism Culture Collection Management Committee on May 12, 2016, and the preservation number is CGMCC No. 11671. Gram-positive actinomycetes and filamentous bacteria are selected from the gram-positive actinomycetes products (Item No. 20201) and filamentous bacteria products (Item No. 20207) of Chengbang microbial flora liquid.

(2) Preparation of PAM flocculant solution

Prepare PAM flocculant solution in advance: choose PAM flocculant from Shandong Nuoer Biotechnology Co., Ltd., the product number is 22800, and the concentration of the PAM flocculant solution is 1‰.

(3) Pretreatment of sludge

After the sludge settles naturally, the lower layer of sludge is removed, and the initial sludge mass concentration needs to be controlled at 23.3 g/L, no need to adjust the sludge pH, the measured result of the sludge pH is 6.44, and the sludge temperature is measured to be 28 ℃, stir the sludge evenly and start to distribute it into 500mL glass bottles, each glass bottle contains 350mL sludge;

(4) Dosing of phage-type bacterial compound bacterial agent;

(5) Chemical reflocculation using PAM flocculant.

The experiment was divided into experimental group and control group.

The sludge of all control and experimental groups was taken from the same batch of pretreated sludge. The lower layer of thick sludge after sedimentation is mixed evenly and then packed into 500mL glass bottles, each bottle is filled with 350mL;

Control group: three 350mL sludges were three parallel samples, 3.5mL ultrapure water was added to the sludge and mixed well;

Experimental group: put the same amount of 350mL mixed uniform sludge into two glass bottles A and B, respectively add 3.5mL of phage-type bacterial compound bacterial agent, and the mixed concentration reaches 10 ⁴ pfu/mL, mix evenly, set three parallel.

Both the experimental group and the control group were placed in a shaker at 30 °C and 150 r/min for 12 h, and the dissolved oxygen concentration in the sludge was 2.5 mg/L. Then, PAM flocculant was added at a concentration of 3 mg/g TSS, and chemical re-flocculation was carried out: first, rapid stirring, rapid stirring for 7 minutes, rapid stirring speed of 200 r/min, rapid stirring followed by conventional stirring for 30 minutes, normal stirring speed After the conventional stirring was completed, 30 mL of sludge was taken out after mixing the sludge in the glass bottle every 3 hours, and the number of Escherichia coli bacteria in the sludge was measured. The test results are shown in Figure 4.

(6) Test results:

The coliform count can indicate the amount of harmful bacteria in the sludge. It can be seen from Figure 4 that after 12 hours of treatment, the microbial pretreatment coupled with PAM flocculant chemical re-flocculation reduced the number of coliform bacteria in the sludge by 40.5% compared with the initial value, which was significantly lower than that of the single use of the phage-type bacterial complex inoculant. At the same time, it decreased by 13.3%, which was 23.5% lower than that of single use of PAM flocculant at the same time. Therefore, it is proved that the sludge dewatering method using the microbial pretreatment coupled with the PAM flocculant chemical re-flocculation in the sludge can achieve the effect of reducing harmful bacteria in the sludge.

Example 4

Referring to Figure 5, this process is used for batch treatment of sludge in the laboratory, and the treated sludge is secondary sedimentation tank sludge produced by A2/O process treatment of municipal sewage.

(1) Preparation of SDWB01 phage-type bacterial solution

Prepare the phage-type bacterial complex solution in advance: Centrifuge and resuspend the cultured Hirudovibrio SDWB01 with a preservation number of CGMCC No. 11671. The concentration of leech vibrio SDWB01 was on the order of 10 ⁶ pfu/mL. The leech vibrio SDWB01 has been deposited in the General Microbiology Center of China Microorganism Culture Collection Management Committee on May 12, 2016.

(2) Preparation of unpurified phage-type bacterial complex solution

The unpurified leech vibrio B1 and B2 were directly separated from the sludge, and the NB solution was used for liquid increase, and the leech vibrio B1 and B2 were centrifuged and resuspended respectively. The concentration of Hirudovibrio in both Hirudovibrio B1 and Hirudovibrio B2 was in the order of 10 ⁶ pfu/mL.

(3) Preparation of PAM flocculant solution

Prepare PAM flocculant solution in advance: choose PAM flocculant from Shandong Nuoer Biotechnology Co., Ltd., the product number is 22800, and the concentration of the PAM flocculant solution is 1‰.

(4) Pretreatment of sludge

After the sludge settles naturally, the lower layer of sludge is removed, and the initial sludge mass concentration needs to be controlled at 23.3 g/L, no need to adjust the sludge pH, the measured result of the sludge pH is 6.44, and the sludge temperature is measured to be 28 ℃, stir the sludge evenly and start to distribute it into 500mL glass bottles, each glass bottle contains 350mL sludge;

(5) Dosing of phage-type bacterial compound bacterial solution;

(6) Chemical reflocculation using PAM flocculant.

The experiment was divided into experimental group and control group.

The sludge of all control and experimental groups was taken from the same batch of pretreated sludge. The lower layer of thick sludge after sedimentation is mixed evenly and then packed into 500mL glass bottles, each bottle is filled with 350mL;

Control group: 3.5mL of Hirudovibrio B1 and 3.5mL of Hirudovibrio B2 were added to an equal amount of 350mL of sludge, mixed well, and three parallel samples were set up for the two bacterial solutions;

Experimental group: put an equal amount of 350 mL of mixed sludge into the glass bottle, add 3.5 mL of Hirudovibrio SDWB01 respectively, and its concentration reaches 10 ⁴ pfu/mL, mix evenly, and set up three parallel samples.

Both the experimental group and the control group were placed in a shaker at 30 °C and 150 r/min for 12 h, and the dissolved oxygen concentration in the sludge was 2 mg/L. Then, PAM flocculant was added at a concentration of 1 mg/g TSS, and chemical re-flocculation was carried out: first, rapid stirring, rapid stirring for 5 minutes, rapid stirring speed of 150 r/min, rapid stirring followed by conventional stirring for 30 minutes, conventional stirring The speed is 50 r/min. After the conventional stirring is completed, 30 mL of sludge is taken out after mixing the sludge in the glass bottle every 4 hours, and the capillary water absorption time of the sludge is measured. The test results are shown in Figure 5.

(7) Test results:

The capillary water absorption time (CST) is used to determine the sludge dewatering performance. The lower the value, the better the sludge dewatering performance. It can be seen from Figure 5 that after 16h reaction time, SDWB01 coupled PAM flocculant has the best chemical reflocculation effect. , the CST value is the lowest, which can prove that SDWB01 is the best strain for microbial lysis coupled with PAM flocculant chemical reflocculation.

Claims (8)

1. a sludge dewatering method using microbial cracking pretreatment coupled with PAM flocculant chemical flocculation, is characterized in that, described method comprises specifically as follows: 1) Preparation of the phage-type bacterial compound agent: the live bacteria in the phage-type bacteria compound agent include at least one or more of leech vibrio, leech vibrio stope, and leech vibrio stahl , and/or comprising one or more of yeast flora, gram-positive actinomycetes, and filamentous flora of fermentation system, wherein the deposit number of a leech vibrio used is CGMCC No.11671; 2) Put the phage-type bacterial compound bacterial agent directly into the remaining sludge to be treated to obtain the sludge after microbial pretreatment; 3) Preparation of PAM flocculant solution; 4) Add the PAM flocculant solution to the sludge after the microbial pretreatment in step 2), stir and then chemically flocculate it. 2. The sludge dewatering method using microbial lysis pretreatment coupled with PAM flocculant chemical flocculation according to claim 1, characterized in that: the concentration of the phage-type bacterial compound inoculant prepared in the step 1) is 10 ⁵ ~10 ¹¹ pfu/mL. 3. The sludge dewatering method using microbial pretreatment coupled with PAM flocculant chemical re-flocculation according to claim 1, characterized in that: in the step 2), the added volume of the phage-type bacterial compound inoculant is to be treated 0.1~1% of the remaining sludge volume. 4. The sludge dewatering method using microbial lysis pretreatment coupled with PAM flocculant chemical flocculation according to claim 1, characterized in that: the phage-type bacterial compound bacterial agent in the step 2) is added into the sludge After that, continuous aeration is carried out to make the dissolved oxygen concentration in the sludge 0.5-5 mg/L. 5. The sludge dewatering method using microbial pyrolysis pretreatment coupled with PAM flocculant chemical flocculation according to claim 1, wherein the concentration range of the PAM flocculant solution prepared in the step 3) is 1-3‰ . 6. The sludge dewatering method using microbial cracking pretreatment coupled with PAM flocculant chemical flocculation according to claim 1, wherein the dosage of the PAM flocculant solution in the step 4) is 0.5~4 mg/ g TSS excess sludge. 7. The sludge dewatering method using microbial cracking pretreatment coupled with PAM flocculant chemical flocculation according to claim 1, characterized in that: the stirring in the step 4) is firstly performed with rapid stirring, and the rapid stirring is performed for 5-10 minutes, and the rapid The stirring speed is 150~250 r/min. After rapid stirring, conventional stirring is performed. The conventional stirring speed is 50 r/min. 8 . The sludge dewatering method using microbial cracking pretreatment coupled with PAM flocculant chemical flocculation according to claim 1 , wherein the initial moisture content of the excess sludge to be treated needs to be controlled at 95-99%. 9 .

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