Sludge dewatering method by combining biological protease with two-stage anaerobic digestion method

Abstract

The invention discloses a sludge dewatering method by combining biological protease with a two-stage anaerobic digestion method, and relates to the technical field of sludge dewatering. The method specifically comprises the following steps: collecting sludge from a sewage treatment system, and pretreating the sludge; putting the pretreated sludge into a stirring kettle for heat treatment and uniform stirring; the biological protease with the proportion of 2: 1 is intermittently put into the stirring kettle, continuous stirring is conducted for 1-2 h, and the stirring speed is controlled to be 260-400 r / min; the stirring kettle is sealed, and the temperature and humidity in the kettle are controlled through heating and water spraying; the treated sludge is subjected to primary anaerobic digestion treatment and secondary anaerobic digestion treatment, organic matters are decomposed through microorganisms, gas is released, and heat is generated. Degradation and decomposition of organic matters in the sludge are promoted, and the solubility and the release rate of the organic matters are improved; the biological protease and other components in the sludge are uniformly distributed, the action effect of the biological protease is improved, and the degradation of organic matters is accelerated.

Description

Technical Field

[0001] The invention relates to the technical field of sludge dehydration, in particular to a sludge dehydration method using a biological protease combined with a secondary anaerobic digestion method. Background Art

[0002] Bioprotease is a naturally occurring biological protein that has the ability to efficiently decompose organic matter and can accelerate the degradation of organic matter in sludge. The secondary anaerobic digestion method is a microbial degradation process carried out under anaerobic conditions, which can effectively degrade organic matter and reduce the volume of sludge. The principle of sludge dehydration by bioprotease combined with secondary anaerobic digestion is to promote the degradation of organic matter in sludge by adding bioprotease, and to use secondary anaerobic digestion to degrade and concentrate sludge, and finally achieve sludge dehydration. This method can not only improve the sludge treatment efficiency, but also reduce energy consumption and the use of chemical agents, and has good environmental and economic benefits. Therefore, bioprotease combined with secondary anaerobic digestion sludge dehydration has broad application prospects in the field of sludge treatment.

[0003] After searching, the Chinese patent application number CN2023117581985 discloses a method and device for dehydrating sludge by combining biological protease with secondary anaerobic digestion. The method includes: hydrolyzing the sludge at 0-140°C, subjecting the sludge after thermal hydrolysis to primary anaerobic digestion at 50-55°C, mixing the sludge after primary anaerobic digestion with biological protease, the amount of biological protease added is 0.5-1‰ of the dry sludge, subjecting the mixed sludge to secondary anaerobic digestion at 37-43°C, adding flocculants and mixing and precipitating, and pressurizing the precipitated sludge multiple times. The method and device for dehydrating sludge by combining biological protease with secondary anaerobic digestion in the above patent have the following shortcomings:

[0004] The above method reduces the temperature of thermal hydrolysis treatment, and the subsequent temperature drop loss of anaerobic digestion is also reduced. The decomposition of extracellular polymers and organic matter is enhanced by biological proteases, and the level of resource utilization is improved. Compared with conventional anaerobic digestion, the gas production rate is increased. However, the viscosity and moisture content of the sludge are relatively high, which increases the burden on subsequent dehydration equipment, increases costs, and requires more time and energy consumption, thereby reducing the sludge dehydration efficiency. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a sludge dehydration method combining biological protease with secondary anaerobic digestion.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for dehydrating sludge by combining biological protease with secondary anaerobic digestion, comprising the following steps:

[0008] S1: Collect sludge from the sewage treatment system and pre-treat the sludge;

[0009] S2: putting the pretreated sludge into a stirring tank for heat treatment and uniform stirring;

[0010] S3: intermittently adding biological protease in a ratio of 2:1 into the stirring tank, stirring continuously for 1-2 hours, and controlling the stirring speed at 260-400r / min;

[0011] S4: The stirring kettle is sealed, and the temperature and humidity in the kettle are controlled by heating and spraying water;

[0012] S5: The treated sludge is subjected to primary anaerobic digestion and secondary anaerobic digestion to decompose organic matter through microorganisms, release gas and generate heat;

[0013] S6: Dehydrating the sludge after the treatment with biological protease combined with secondary anaerobic digestion to obtain dry sludge solids.

[0014] Preferably: in the step S4, the temperature in the stirring kettle is maintained at 45-60°C, the humidity is maintained at 50-70%, and the static time is 3-5h.

[0015] Furthermore: in the step S2, the stirring speed is controlled at 350-820 r / min, and the heating temperature is controlled at 50-70°C.

[0016] On the basis of the above scheme: In the step S1, the sludge is pretreated, and the specific method is as follows:

[0017] S11: 500 g of sludge was collected from a sewage treatment system and immersed in 220 ml of a sulfonate-type ionic liquid;

[0018] S12: mixing the sludge and the sulfonate ionic liquid to react, and maintaining the heating temperature at 20-35° C.;

[0019] S13: After standing for 1-2 hours, the sludge mixed with the sulfonate ionic liquid is introduced into a centrifuge for solid-liquid separation after filtration;

[0020] S14: Drying the sludge from which the sulfonate type ionic liquid has been removed, evaporating the excess sulfonate type ionic liquid, and dissolving the solid sludge in 300 ml of water for later use.

[0021] A better solution among the above solutions is: in the step S12, the mixing and stirring reaction speed is 150r / min, and the mixing and stirring reaction time is 30-50min.

[0022] As a further solution of the present invention: the primary anaerobic digestion treatment in step S5 has the following specific steps:

[0023] Primary anaerobic digestion treatment:

[0024] A1: Select methanogens and anaerobic ammonia-oxidizing bacteria as microbial strains and put them into the primary anaerobic digestion reactor to establish a co-culture system;

[0025] A2: Regulate the environmental conditions within the co-culture system;

[0026] A3: Regulate the ratio and density of methanogens and anaerobic ammonium oxidizers to promote interaction and synergistic effects between the two;

[0027] A4: The sludge treated with biological protease is put into the primary anaerobic digestion reactor for primary sludge organic matter degradation treatment.

[0028] Meanwhile, in the step A2, the temperature in the co-culture system is controlled to be 35-40° C., the pH value is 6.5-7.5, anaerobic, the carbon source is 1-5%, the nitrogen source is 0.4-1% and the phosphorus source is 0.1-0.3%.

[0029] As a preferred embodiment of the present invention: in the step A3, the number ratio of methanogens to anaerobic ammonia oxidizing bacteria is controlled between 2:1, and the density is controlled at 10^6-10^8 cells / mL.

[0030] Meanwhile, the specific steps of the secondary anaerobic digestion treatment in step S5 are as follows:

[0031] Secondary anaerobic digestion treatment:

[0032] B1: Build a secondary anaerobic digestion reactor and use porous ceramics as the carrier material required for immobilizing microorganisms;

[0033] B2: Methanogens and sulfur-reducing bacteria were selected as microbial strains, which were inoculated onto porous ceramics to allow the microorganisms to adhere to the surface to form a fixed microbial film, and vitamin B and glutamic acid in a ratio of 3:2 were introduced into the secondary anaerobic digestion reactor.

[0034] B3: Regulate the environmental conditions in the system, the temperature in the system is 30-50°C, the pH value is 6-7.6, oxygen is absent, the carbon source is 1-4%, the nitrogen source is 0.4-1.2% and the phosphorus source is 0.2-0.4%;

[0035] B4: The sludge after the primary anaerobic digestion treatment is introduced into the secondary anaerobic digestion reactor to allow the sludge to fully contact with the porous ceramic surface to complete the secondary sludge organic matter degradation treatment.

[0036] As a more optimal solution of the present invention: in the step S6, the sludge after the biological protease combined with the secondary anaerobic digestion is dehydrated, and the specific steps are as follows:

[0037] S61: putting the sludge into the dehydration area of ​​the magnetic field assisted centrifugal dehydrator;

[0038] S62: applying an electric field to the dehydration area to act on the sludge, controlling the movement of microorganisms and particulate matter, and promoting the separation and discharge of water. The applied electric field is controlled at 2-15 kV / m;

[0039] S63: During the dehydration process, the moisture content and dehydration efficiency are monitored by a moisture meter, and the electric field parameters are adjusted according to the actual situation;

[0040] S64: The liquid wastewater generated during the dehydration process is treated by sedimentation and filtration methods before being discharged.

[0041] The beneficial effects of the present invention are:

[0042] 1. A sludge dehydration method combining biological protease with secondary anaerobic digestion method comprises the following steps: putting the pretreated sludge into a stirring tank for heat treatment and uniform stirring, and intermittently adding biological protease in a ratio of 2:1 into the stirring tank. At the same time, the stirring tank is sealed, and the temperature and humidity in the tank are controlled by heating and spraying water, so as to promote the degradation and decomposition of organic matter in the sludge, and improve the solubility and release rate of organic matter; make the biological protease and other components in the sludge evenly distributed, improve the effect of the biological protease, and accelerate the degradation of organic matter; at the same time, help the biological protease to fully contact with the organic matter in the sludge, improve the degradation efficiency, and use the microorganisms in the sludge for further fermentation and degradation under certain temperature and humidity conditions, promote the degradation and release of organic matter, and maintain suitable temperature and humidity, which is conducive to the growth and activity of microorganisms and improves the digestion efficiency.

[0043] 2. A sludge dehydration method combining a biological protease with a secondary anaerobic digestion method, wherein the sludge is immersed in an ionic liquid, and the dissolving ability of the ionic liquid can be used to effectively remove organic matter in the sludge, thereby improving the treatment efficiency; and mixing and stirring the sludge and the ionic liquid and maintaining a suitable temperature can help promote the degradation of organic matter and accelerate the sludge treatment process; at the same time, through filtration and solid-liquid separation treatment, the ionic liquid and dissolved organic matter can be effectively separated, thereby reducing energy consumption in subsequent treatment processes.

[0044] 3. A method for dehydrating sludge by combining a biological protease with a secondary anaerobic digestion method. In the primary anaerobic digestion treatment process, methanogens and anaerobic ammonia-oxidizing bacteria are selected as microbial strains to establish a co-culture system, which can promote the degradation of organic matter and improve gas production efficiency. The environmental conditions in the system, including temperature, pH value, carbon source, nitrogen source and phosphorus source, are regulated to provide suitable conditions for the growth and metabolism of microorganisms. At the same time, the ratio and density of methanogens and anaerobic ammonia-oxidizing bacteria are controlled to promote interaction and synergistic effects between the two and enhance the degradation effect of organic matter. In the secondary anaerobic digestion treatment process, methanogens and sulfur-reducing bacteria are selected as microbial strains and fixed on porous ceramics, and vitamin B and glutamic acid are introduced to promote microbial activity and organic matter degradation efficiency, increase the degradation area of ​​microorganisms, improve the quality of organic matter degradation, and fully promote gas production and heat release during sludge treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a main flow chart of a biological protease combined with secondary anaerobic digestion sludge dehydration method proposed by the present invention;

[0046] Figure 2 This is a flow chart of pre-treating sludge in a sludge dehydration method using a biological protease combined with a secondary anaerobic digestion method proposed by the present invention;

[0047] Figure 3 This is a flow chart of the primary anaerobic digestion treatment in a sludge dehydration method using a biological protease combined with a secondary anaerobic digestion method proposed by the present invention;

[0048] Figure 4 This is a flow chart of a sludge dehydration method using a biological protease combined with a secondary anaerobic digestion method proposed by the present invention;

[0049] Figure 5 The present invention provides a flow chart of a sludge dehydration method using a biological protease combined with a secondary anaerobic digestion method. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.

[0051] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0052] A sludge dehydration method using biological protease combined with secondary anaerobic digestion, Figure 1 As shown, the following steps are included:

[0053] S1: Collect sludge from the sewage treatment system and pre-treat the sludge;

[0054] S2: The pretreated sludge is put into a stirring tank for heat treatment and uniform stirring. The stirring speed is controlled at 350-820r / min and the heating temperature is controlled at 50-70℃;

[0055] S3: intermittently adding biological protease in a ratio of 2:1 into the stirring tank, stirring continuously for 1-2 hours, and controlling the stirring speed at 260-400r / min;

[0056] S4: The stirring kettle is sealed, and the temperature and humidity in the kettle are controlled by heating and water spraying. The temperature in the kettle is maintained at 45-60°C, and the humidity is maintained at 50-70%. The kettle is left to stand for 3-5 hours;

[0057] S5: The treated sludge is subjected to primary anaerobic digestion and secondary anaerobic digestion to decompose organic matter through microorganisms, release gas and generate heat;

[0058] S6: Dehydrating the sludge after the treatment with biological protease combined with secondary anaerobic digestion to obtain dry sludge solids.

[0059] Through the S2-S4 steps, the degradation and decomposition of organic matter in the sludge can be promoted, the solubility and release rate of organic matter can be improved; the biological protease and other components in the sludge can be evenly distributed, the effect of the biological protease can be improved, and the degradation of organic matter can be accelerated; at the same time, it helps the biological protease to fully contact with the organic matter in the sludge, improve the degradation efficiency, and under certain temperature and humidity conditions, the microorganisms in the sludge are used for further fermentation and degradation, which promotes the degradation and release of organic matter, and maintaining suitable temperature and humidity is conducive to the growth and activity of microorganisms, thereby improving digestion efficiency.

[0060] Among them, Figure 2 As shown, in the step S1, the sludge is pretreated, and the specific method is as follows:

[0061] S11: 500 g of sludge was collected from a sewage treatment system and immersed in 220 ml of a sulfonate-type ionic liquid;

[0062] S12: mixing the sludge and the sulfonate ionic liquid at a speed of 150 r / min and stirring for 30-50 min, and maintaining the heating temperature at 20-35° C.;

[0063] S13: After standing for 1-2 hours, the sludge mixed with the sulfonate ionic liquid is introduced into a centrifuge for solid-liquid separation after filtration;

[0064] S14: Drying the sludge from which the sulfonate type ionic liquid has been removed, evaporating the excess sulfonate type ionic liquid, and dissolving the solid sludge in 300 ml of water for later use.

[0065] By soaking the sludge in ionic liquid, the dissolving ability of ionic liquid can be used to effectively remove organic matter in the sludge, thereby improving the treatment efficiency. Mixing and stirring the sludge and ionic liquid and maintaining a suitable temperature can help promote the degradation of organic matter and accelerate the sludge treatment process. At the same time, through filtration and solid-liquid separation treatment, the ionic liquid and dissolved organic matter can be effectively separated, reducing energy consumption in the subsequent treatment process.

[0066] like Figure 3 and Figure 4 As shown, in the step S5, the specific steps are as follows:

[0067] A: Primary anaerobic digestion treatment:

[0068] A1: Select methanogens and anaerobic ammonia-oxidizing bacteria as microbial strains and put them into the primary anaerobic digestion reactor to establish a co-culture system;

[0069] A2: Regulate the environmental conditions in the co-culture system, control the temperature in the system to 35-40°C, pH 6.5-7.5, anaerobic, carbon source 1-5%, nitrogen source 0.4-1% and phosphorus source 0.1-0.3%;

[0070] A3: Adjust the ratio and density of methanogens and anaerobic ammonium oxidizers, control the number ratio of methanogens and anaerobic ammonium oxidizers between 2:1, and control the density at 10^6-10^8 cells / mL to promote the interaction and synergistic effect between the two;

[0071] A4: The sludge treated with biological protease is put into the primary anaerobic digestion reactor for primary sludge organic matter degradation treatment.

[0072] B: Secondary anaerobic digestion treatment:

[0073] B1: Build a secondary anaerobic digestion reactor and use porous ceramics as the carrier material required for immobilizing microorganisms;

[0074] B2: Methanogens and sulfur-reducing bacteria were selected as microbial strains, which were inoculated onto porous ceramics to allow the microorganisms to adhere to the surface to form a fixed microbial film, and vitamin B and glutamic acid in a ratio of 3:2 were introduced into the secondary anaerobic digestion reactor.

[0075] B3: Regulate the environmental conditions in the system, the temperature in the system is 30-50°C, the pH value is 6-7.6, oxygen is absent, the carbon source is 1-4%, the nitrogen source is 0.4-1.2% and the phosphorus source is 0.2-0.4%;

[0076] B4: The sludge after the primary anaerobic digestion treatment is introduced into the secondary anaerobic digestion reactor to allow the sludge to fully contact with the porous ceramic surface to complete the secondary sludge organic matter degradation treatment.

[0077] In the primary anaerobic digestion process, methanogens and anaerobic ammonia-oxidizing bacteria are selected as microbial strains to establish a co-culture system, which can promote the degradation of organic matter and improve gas production efficiency. The environmental conditions in the system, including temperature, pH value, carbon source, nitrogen source and phosphorus source, are regulated to provide suitable conditions for the growth and metabolism of microorganisms. At the same time, the ratio and density of methanogens and anaerobic ammonia-oxidizing bacteria are controlled to promote interaction and synergistic effects between the two and enhance the degradation effect of organic matter. In the secondary anaerobic digestion process, methanogens and sulfur-reducing bacteria are selected as microbial strains and fixed on porous ceramics. Vitamin B and glutamate are introduced to promote microbial activity and organic matter degradation efficiency, increase the degradation area of ​​microorganisms, improve the quality of organic matter degradation, and fully promote gas production and heat release during sludge treatment.

[0078] In the step S6, the sludge treated with biological protease combined with secondary anaerobic digestion is dehydrated, and the specific steps are as follows:

[0079] S61: putting the sludge into the dehydration area of ​​the magnetic field assisted centrifugal dehydrator;

[0080] S62: applying an electric field to the dehydration area to act on the sludge, controlling the movement of microorganisms and particulate matter, and promoting the separation and discharge of water. The applied electric field is controlled at 2-15 kV / m;

[0081] S63: During the dehydration process, the moisture content and dehydration efficiency are monitored by a moisture meter, and the electric field parameters are adjusted according to the actual situation;

[0082] S64: The liquid wastewater generated during the dehydration process is treated by sedimentation and filtration methods before being discharged.

[0083] Embodiment 1:

[0084] A method for dehydrating sludge by combining biological protease with secondary anaerobic digestion, such as Figure 1 As shown, the following steps are included:

[0085] S1: Collect sludge from the sewage treatment system and pre-treat the sludge;

[0086] S2: The pretreated sludge is put into a stirring tank for heat treatment and uniform stirring. The stirring speed is controlled at 350r / min and the heating temperature is controlled at 50℃;

[0087] S3: intermittently add biological protease in a ratio of 2:1 into the stirring tank, stir continuously for 1 hour, and control the stirring speed at 260r / min;

[0088] S4: The stirring kettle is sealed, and the temperature and humidity in the kettle are controlled by heating and spraying water. The temperature in the kettle is maintained at 45°C and the humidity is maintained at 50%. The kettle is left stationary for 3 hours.

[0089] S5: The treated sludge is subjected to primary anaerobic digestion and secondary anaerobic digestion to decompose organic matter through microorganisms, release gas and generate heat;

[0090] S6: Dehydrating the sludge after the treatment with biological protease combined with secondary anaerobic digestion to obtain dry sludge solids.

[0091] Among them, Figure 2 As shown, in the step S1, the sludge is pretreated, and the specific method is as follows:

[0092] S11: 500 g of sludge was collected from a sewage treatment system and immersed in 220 ml of a sulfonate-type ionic liquid;

[0093] S12: mixing the sludge and the sulfonate ionic liquid at a speed of 150 r / min for 30 min, and maintaining the heating temperature at 20°C;

[0094] S13: After standing for 1 hour, the sludge mixed with the sulfonate type ionic liquid is introduced into a centrifuge for solid-liquid separation after filtration;

[0095] S14: Drying the sludge from which the sulfonate type ionic liquid has been removed, evaporating the excess sulfonate type ionic liquid, and dissolving the solid sludge in 300 ml of water for later use.

[0096] like Figure 3 and Figure 4 As shown, in the step S5, the specific steps are as follows:

[0097] A: Primary anaerobic digestion treatment:

[0098] A1: Select methanogens and anaerobic ammonia-oxidizing bacteria as microbial strains and put them into the primary anaerobic digestion reactor to establish a co-culture system;

[0099] A2: Regulate the environmental conditions in the co-culture system, and control the temperature in the system to be 35°C, pH 6.5, anaerobic, 1% carbon source, 0.4% nitrogen source, and 0.1% phosphorus source;

[0100] A3: Adjust the ratio and density of methanogens and anaerobic ammonium oxidizers, control the number ratio of methanogens and anaerobic ammonium oxidizers at 2:1, and control the density at 10^6 cells / mL to promote the interaction and synergistic effect between the two;

[0101] A4: The sludge treated with biological protease is put into the primary anaerobic digestion reactor for primary sludge organic matter degradation treatment.

[0102] B: Secondary anaerobic digestion treatment:

[0103] B1: Build a secondary anaerobic digestion reactor and use porous ceramics as the carrier material required for immobilizing microorganisms;

[0104] B2: Methanogens and sulfur-reducing bacteria were selected as microbial strains, which were inoculated onto porous ceramics to allow the microorganisms to adhere to the surface to form a fixed microbial film, and vitamin B and glutamic acid in a ratio of 3:2 were introduced into the secondary anaerobic digestion reactor.

[0105] B3: Regulate the environmental conditions in the system, and control the temperature in the system to be 30°C, pH value to be 6, oxygen-free, carbon source 1%, nitrogen source 0.4% and phosphorus source 0.2%;

[0106] B4: The sludge after the primary anaerobic digestion treatment is introduced into the secondary anaerobic digestion reactor to allow the sludge to fully contact with the porous ceramic surface to complete the secondary sludge organic matter degradation treatment.

[0107] like Figure 5 As shown, in the step S6, the sludge treated by the biological protease combined with the secondary anaerobic digestion is dehydrated, and the specific steps are as follows:

[0108] S61: putting the sludge into the dehydration area of ​​the magnetic field assisted centrifugal dehydrator;

[0109] S62: applying an electric field to the dehydration area to act on the sludge, controlling the movement of microorganisms and particulate matter, and promoting the separation and discharge of water. The applied electric field is controlled at 2 kV / m;

[0110] S63: During the dehydration process, the moisture content and dehydration efficiency are monitored by a moisture meter, and the electric field parameters are adjusted according to the actual situation;

[0111] S64: The liquid wastewater generated during the dehydration process is treated by sedimentation and filtration methods before being discharged.

[0112] Embodiment 2:

[0113] A method for dehydrating sludge by combining biological protease with secondary anaerobic digestion, such as Figure 1 As shown,

[0114] The following steps are involved:

[0115] S1: Collect sludge from the sewage treatment system and pre-treat the sludge;

[0116] S2: The pretreated sludge is put into a stirring tank for heat treatment and uniform stirring. The stirring speed is controlled at 710r / min and the heating temperature is controlled at 62°C;

[0117] S3: intermittently add biological protease in a ratio of 2:1 into the stirring tank, stir continuously for 1.3 hours, and control the stirring speed at 320r / min;

[0118] S4: The stirring kettle is sealed, and the temperature and humidity in the kettle are controlled by heating and spraying water. The temperature in the kettle is maintained at 51°C and the humidity is maintained at 60%. The kettle is left stationary for 4 hours.

[0119] S5: The treated sludge is subjected to primary anaerobic digestion and secondary anaerobic digestion to decompose organic matter through microorganisms, release gas and generate heat;

[0120] S6: Dehydrating the sludge after the treatment with biological protease combined with secondary anaerobic digestion to obtain dry sludge solids.

[0121] Among them, Figure 2 As shown, in the step S1, the sludge is pretreated, and the specific method is as follows:

[0122] S11: 500 g of sludge was collected from a sewage treatment system and immersed in 220 ml of a sulfonate-type ionic liquid;

[0123] S12: mixing the sludge and the sulfonate ionic liquid at a speed of 150 r / min for 43 min, and maintaining the heating temperature at 30°C;

[0124] S13: After standing for 1.4 hours, the sludge mixed with the sulfonate type ionic liquid is introduced into a centrifuge for solid-liquid separation after filtration;

[0125] S14: Drying the sludge from which the sulfonate type ionic liquid has been removed, evaporating the excess sulfonate type ionic liquid, and dissolving the solid sludge in 300 ml of water for later use.

[0126] like Figure 3 and Figure 4 As shown, in the step S5, the specific steps are as follows:

[0127] A: Primary anaerobic digestion treatment:

[0128] A1: Select methanogens and anaerobic ammonia-oxidizing bacteria as microbial strains and put them into the primary anaerobic digestion reactor to establish a co-culture system;

[0129] A2: Regulate the environmental conditions in the co-culture system, and control the temperature in the system to 36°C, pH 7, anaerobic, 2.5% carbon source, 0.6% nitrogen source, and 0.15% phosphorus source;

[0130] A3: Adjust the ratio and density of methanogens and anaerobic ammonium oxidizers, control the number ratio of methanogens and anaerobic ammonium oxidizers at 2:1, and control the density at 10^6.8 cells / mL to promote the interaction and synergistic effect between the two;

[0131] A4: The sludge treated with biological protease is put into the primary anaerobic digestion reactor for primary sludge organic matter degradation treatment.

[0132] B: Secondary anaerobic digestion treatment:

[0133] B1: Build a secondary anaerobic digestion reactor and use porous ceramics as the carrier material required for immobilizing microorganisms;

[0134] B2: Methanogens and sulfur-reducing bacteria were selected as microbial strains, which were inoculated onto porous ceramics to allow the microorganisms to adhere to the surface to form a fixed microbial film, and vitamin B and glutamic acid in a ratio of 3:2 were introduced into the secondary anaerobic digestion reactor.

[0135] B3: Control the environmental conditions in the system, and control the temperature in the system to be 42°C, pH value to be 7.2, oxygen-free, carbon source 3%, nitrogen source 1% and phosphorus source 0.32%;

[0136] B4: The sludge after the primary anaerobic digestion treatment is introduced into the secondary anaerobic digestion reactor to allow the sludge to fully contact with the porous ceramic surface to complete the secondary sludge organic matter degradation treatment.

[0137] In the step S6, the sludge treated with biological protease combined with secondary anaerobic digestion is dehydrated, and the specific steps are as follows:

[0138] S61: putting the sludge into the dehydration area of ​​the magnetic field assisted centrifugal dehydrator;

[0139] S62: applying an electric field to the dehydration area to act on the sludge, controlling the movement of microorganisms and particulate matter, and promoting the separation and discharge of water. The applied electric field is controlled at 8 kV / m;

[0140] S63: During the dehydration process, the moisture content and dehydration efficiency are monitored by a moisture meter, and the electric field parameters are adjusted according to the actual situation;

[0141] S64: The liquid wastewater generated during the dehydration process is treated by sedimentation and filtration methods before being discharged.

[0142] Embodiment 3:

[0143] A method for dehydrating sludge by combining biological protease with secondary anaerobic digestion, such as Figure 1 As shown, the following steps are included:

[0144] S1: Collect sludge from the sewage treatment system and pre-treat the sludge;

[0145] S2: The pretreated sludge is put into a stirring tank for heat treatment and uniform stirring. The stirring speed is controlled at 820r / min and the heating temperature is controlled at 70℃;

[0146] S3: intermittently adding biological protease in a ratio of 2:1 into the stirring tank, stirring continuously for 2 hours, and the stirring speed is controlled at 400r / min;

[0147] S4: The stirring kettle is sealed, and the temperature and humidity in the kettle are controlled by heating and spraying water. The temperature in the kettle is maintained at 60°C and the humidity is maintained at 70%. The kettle is left stationary for 5 hours.

[0148] S5: The treated sludge is subjected to primary anaerobic digestion and secondary anaerobic digestion to decompose organic matter through microorganisms, release gas and generate heat;

[0149] S6: Dehydrating the sludge after the treatment with biological protease combined with secondary anaerobic digestion to obtain dry sludge solids.

[0150] Among them, Figure 2 As shown, in the step S1, the sludge is pretreated, and the specific method is as follows:

[0151] S11: 500 g of sludge was collected from a sewage treatment system and immersed in 220 ml of a sulfonate-type ionic liquid;

[0152] S12: mixing the sludge and the sulfonate ionic liquid at a speed of 150 r / min for 50 min, and maintaining the heating temperature at 35°C;

[0153] S13: After standing for 2 hours, the sludge mixed with the sulfonate ionic liquid is introduced into a centrifuge for solid-liquid separation after filtration;

[0154] S14: Drying the sludge from which the sulfonate type ionic liquid has been removed, evaporating the excess sulfonate type ionic liquid, and dissolving the solid sludge in 300 ml of water for later use.

[0155] like Figure 3 and Figure 4 As shown, in the step S5, the specific steps are as follows:

[0156] A: Primary anaerobic digestion treatment:

[0157] A1: Select methanogens and anaerobic ammonia-oxidizing bacteria as microbial strains and put them into the primary anaerobic digestion reactor to establish a co-culture system;

[0158] A2: Regulate the environmental conditions in the co-culture system, and control the temperature in the system to be 40°C, pH 7.5, anaerobic, 5% carbon source, 1% nitrogen source, and 0.3% phosphorus source;

[0159] A3: Adjust the ratio and density of methanogens and anaerobic ammonium oxidizers, control the number ratio of methanogens and anaerobic ammonium oxidizers at 2:1, and control the density at 10^8 cells / mL to promote the interaction and synergistic effect between the two;

[0160] A4: The sludge treated with biological protease is put into the primary anaerobic digestion reactor for primary sludge organic matter degradation treatment.

[0161] B: Secondary anaerobic digestion treatment:

[0162] B1: Build a secondary anaerobic digestion reactor and use porous ceramics as the carrier material required for immobilizing microorganisms;

[0163] B2: Methanogens and sulfur-reducing bacteria were selected as microbial strains, which were inoculated onto porous ceramics to allow the microorganisms to adhere to the surface to form a fixed microbial film, and vitamin B and glutamic acid in a ratio of 3:2 were introduced into the secondary anaerobic digestion reactor.

[0164] B3: Regulate the environmental conditions in the system, and control the temperature in the system to be 50°C, pH value to be 7.6, oxygen-free, carbon source 4%, nitrogen source 1.2% and phosphorus source 0.4%;

[0165] B4: The sludge after the primary anaerobic digestion treatment is introduced into the secondary anaerobic digestion reactor to allow the sludge to fully contact with the porous ceramic surface to complete the secondary sludge organic matter degradation treatment.

[0166] like Figure 5 As shown, in the step S6, the sludge treated by the biological protease combined with the secondary anaerobic digestion is dehydrated, and the specific steps are as follows:

[0167] S61: putting the sludge into the dehydration area of ​​the magnetic field assisted centrifugal dehydrator;

[0168] S62: applying an electric field to the dehydration area to act on the sludge, controlling the movement of microorganisms and particulate matter, and promoting the separation and discharge of water. The applied electric field is controlled at 15 kV / m;

[0169] S63: During the dehydration process, the moisture content and dehydration efficiency are monitored by a moisture meter, and the electric field parameters are adjusted according to the actual situation;

[0170] S64: The liquid wastewater generated during the dehydration process is treated by sedimentation and filtration methods before being discharged.

[0171] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for dehydrating sludge by combining biological protease with secondary anaerobic digestion, characterized in that: The following steps are involved: S1: Collect sludge from the sewage treatment system and pre-treat the sludge; S2: putting the pretreated sludge into a stirring tank for heat treatment and uniform stirring; S3: intermittently adding biological protease in a ratio of 2:1 into the stirring tank, stirring continuously for 1-2 hours, and controlling the stirring speed at 260-400r / min; S4: The stirring kettle is sealed, and the temperature and humidity in the kettle are controlled by heating and spraying water; S5: The treated sludge is subjected to primary anaerobic digestion and secondary anaerobic digestion to decompose organic matter through microorganisms, release gas and generate heat; S6: Dehydrating the sludge after the treatment with biological protease combined with secondary anaerobic digestion to obtain dry sludge solids.

2. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 1, characterized in that: In the step S4, the temperature in the stirring kettle is maintained at 45-60° C., the humidity is maintained at 50-70%, and the static time is 3-5 hours.

3. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 1, characterized in that: In the step S2, the stirring speed is controlled at 350-820 r / min, and the heating temperature is controlled at 50-70°C.

4. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 1, characterized in that: In the step S1, the sludge is pretreated, and the specific method is as follows: S11: 500 g of sludge was collected from a sewage treatment system and immersed in 220 ml of a sulfonate-type ionic liquid; S12: mixing the sludge and the sulfonate ionic liquid to react, and maintaining the heating temperature at 20-35° C.; S13: After standing for 1-2 hours, the sludge mixed with the sulfonate ionic liquid is introduced into a centrifuge for solid-liquid separation after filtration; S14: Drying the sludge from which the sulfonate type ionic liquid has been removed, evaporating the excess sulfonate type ionic liquid, and dissolving the solid sludge in 300 ml of water for later use.

5. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 4, characterized in that: In the step S12, the mixing and stirring reaction speed is 150 r / min, and the mixing and stirring reaction time is 30-50 min.

6. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 1, characterized in that: The specific steps of the primary anaerobic digestion treatment in step S5 are as follows: Primary anaerobic digestion treatment: A1: Select methanogens and anaerobic ammonia-oxidizing bacteria as microbial strains and put them into the primary anaerobic digestion reactor to establish a co-culture system; A2: Regulate the environmental conditions within the co-culture system; A3: Regulate the ratio and density of methanogens and anaerobic ammonium oxidizers to promote interaction and synergistic effects between the two; A4: The sludge treated with biological protease is put into the primary anaerobic digestion reactor for primary sludge organic matter degradation treatment.

7. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 6, characterized in that: In the step A2, the temperature in the co-culture system is controlled to be 35-40° C., the pH value is 6.5-7.5, anaerobic, the carbon source is 1-5%, the nitrogen source is 0.4-1% and the phosphorus source is 0.1-0.3%.

8. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 6, characterized in that: In the step A3, the ratio of the number of methanogens to that of anaerobic ammonia oxidizing bacteria is controlled between 2:1, and the density is controlled between 10^6-10^8 cells / mL.

9. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 1, characterized in that: The specific steps of the secondary anaerobic digestion treatment in step S5 are as follows: Secondary anaerobic digestion treatment: B1: Build a secondary anaerobic digestion reactor and use porous ceramics as the carrier material required for immobilizing microorganisms; B2: Methanogens and sulfur-reducing bacteria were selected as microbial strains, which were inoculated onto porous ceramics to allow the microorganisms to adhere to the surface to form a fixed microbial film, and vitamin B and glutamic acid in a ratio of 3:2 were introduced into the secondary anaerobic digestion reactor. B3： Regulating the environmental conditions in the system, the temperature in the system is 30-50°C, the pH value is 6-7.6, oxygen is absent, the carbon source is 1-4%, the nitrogen source is 0.4-1.2% and the phosphorus source is 0.2-0.4%; B4: The sludge after the primary anaerobic digestion treatment is introduced into the secondary anaerobic digestion reactor to allow the sludge to fully contact with the porous ceramic surface to complete the secondary sludge organic matter degradation treatment.

10. The method for dehydrating sludge by combining biological protease with secondary anaerobic digestion according to claim 1, characterized in that: In the step S6, the sludge treated with biological protease combined with secondary anaerobic digestion is dehydrated, and the specific steps are as follows: S61: putting the sludge into the dehydration area of ​​the magnetic field assisted centrifugal dehydrator; S62: applying an electric field to the dehydration area to act on the sludge, controlling the movement of microorganisms and particulate matter, and promoting the separation and discharge of water. The applied electric field is controlled at 2-15 kV / m; S63: During the dehydration process, the moisture content and dehydration efficiency are monitored by a moisture meter, and the electric field parameters are adjusted according to the actual situation; S64: The liquid wastewater generated during the dehydration process is treated by sedimentation and filtration methods before being discharged.

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