Sludge utilization system and process method

Abstract

The invention discloses a sludge utilization system and a process method. The sludge utilization system comprises a sludge concentration unit, a pipeline ultrasonic unit, a degradation unit and a dehydration unit which are connected in sequence, the sludge concentration unit is used for concentrating the stored sludge; the pipeline ultrasonic unit is used for carrying out ultrasonic treatment on sludge in a pipeline; the degradation unit is used for degrading organic matters in the sludge, the degradation unit is provided with a feed port for adding alkali and enzyme, and the enzyme is amylase and liquefying enzyme. According to the sludge utilization system and the process method, improvement is carried out on the basis of an existing treatment facility, ultrasonic, alkali and enzyme combined treatment is utilized, the dehydration performance of the sludge is effectively improved, dependence of a subsequent dehydration unit on a flocculation agent and / or a flocculation auxiliary agent is avoided, the sludge treatment cost is greatly reduced, and the filtrate obtained through dehydration can be recycled and reused. The carbon source can be reused in a sewage treatment system as an auxiliary carbon source.

Description

Technical Field

[0001] The present application belongs to the technical field of sludge resource utilization, and specifically relates to an economical and efficient sludge utilization system and process method. Background Art

[0002] In recent years, with the continuous improvement of sewage treatment efficiency in my country, the amount of sludge produced has also shown an increasing trend year by year. The residual sludge contains a large amount of water, and the presence of extracellular polymers (EPS) makes it difficult to remove the water. In addition, my country's sludge treatment started late, and the residual sludge is generally directly concentrated and mechanically dehydrated, and the dehydrated sludge with a moisture content of more than 80% is directly sent to the landfill for sanitary landfill. This method not only occupies land, but also easily causes secondary pollution to groundwater and soil. In the 3R (Reduce, Recycle, Reuse) principle followed by the sludge treatment and disposal process, sludge reduction (Reduce) is the first problem to be solved. Reducing the amount of sludge produced from the source and reducing the sludge volume from the end without causing secondary pollution is an important topic that needs urgent attention in current environmental issues.

[0003] Tian Yuechen et al. found in their experimental study on the combined pretreatment of residual sludge by ultrasound and alkali that dehydration of the sludge treated with ultrasound and Ca(0H)2 will greatly improve the entire sludge treatment and disposal process, and provide technical guidance for promoting sludge stabilization, reduction and resource utilization (Master of Engineering Thesis, Southeast University, Experimental Study on the Combined Pretreatment of Residual Sludge by Ultrasonic and Alkali, Tian Yuechen, 2017).

[0004] CN112551843A discloses a method for improving sludge dewatering performance by combining biological leaching with ultrasound. The original sludge is treated with energy substances sulfur powder and ferrous sulfate to enrich indigenous acidophilic thiobacillus to obtain acidified inoculated sludge; then the cultured acidified inoculated sludge is added to the sludge to be treated for biological leaching treatment; then the sludge is ultrasonically treated and mechanically dehydrated. The moisture content of the conditioned sludge can be reduced to 70%-73%; the sludge filtration resistance (SRF) is lower than 4×1011cm / g; the total organic carbon (TOC) concentration, ammonia nitrogen concentration and organic matter (COD) concentration of the supernatant are increased; the total protein content in the extracellular polymer (EPS) is reduced, which is beneficial to sludge dewatering. The method of the invention can reduce the sludge filtration resistance, improve the sludge dewatering performance, save the sludge treatment cost, and has no secondary pollution. However, the biological leaching treatment time of the invention is long and requires a large amount of land, which is not suitable for promotion and application.

[0005] It is of great significance to develop a sludge utilization system and process method based on existing sewage treatment facilities to solve the problems of high sludge treatment cost and large area occupation. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides an economical and efficient sludge utilization system and process method.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A sludge utilization system comprises a sludge concentration unit, a pipeline ultrasonic unit, a degradation unit and a dehydration unit which are connected in sequence;

[0009] The sludge concentration unit is configured to: concentrate the stored sludge;

[0010] The pipeline ultrasonic unit is configured to: perform ultrasonic treatment on the sludge in the pipeline;

[0011] The degradation unit is configured to: degrade organic matter in the sludge, wherein the degradation unit is provided with a feed port for adding alkali and enzymes, wherein the enzymes include amylase and liquefaction enzyme;

[0012] The dehydration unit is configured to dehydrate the sludge.

[0013] The main body of the sludge concentration unit in the present invention may be a pool or a tank, such as a sludge concentration unit may be a sludge concentration pool or a sludge concentration tank; preferably, the volume of the sludge concentration unit does not exceed 50% of the volume of the sludge storage pool.

[0014] Further preferably, the upper liquid level of the sludge concentration unit is lower than the upper liquid level of the sludge storage tank, and the lower liquid level of the sludge concentration unit is lower than the lower liquid level of the sludge storage tank, so that a potential energy difference is formed between the two. At the same time, a valve is provided between the sludge concentration unit and the sludge storage tank to further squeeze the sludge.

[0015] Further preferably, the sludge concentration unit is provided with a stirring device.

[0016] The main body of the pipeline ultrasonic unit in the present invention is a pipeline, and an ultrasonic device is arranged in the pipeline. The pipeline in the present invention can also be replaced by a container (tower) with a length-to-diameter ratio greater than 2.

[0017] Preferably, the intensity of the pipeline ultrasonic unit is 2-4w / mL, and the residence time is 10-20min.

[0018] The main body of the degradation unit in the present invention may be a pool, a tank or a tower, for example, the degradation unit may be a degradation pool, a degradation tank or a degradation tower, etc. Preferably, the degradation unit is provided with a stirring device.

[0019] Preferably, the degradation unit is provided with at least one feeding port for adding alkali, amylase and liquefaction enzyme.

[0020] Further preferably, the alkali is sodium hydroxide and / or calcium oxide, and even more preferably, the alkali is sodium hydroxide and calcium oxide in a mass ratio of 1:1 to 10:1.

[0021] Further preferably, the addition amount of the amylase and the liquefaction enzyme is 1-5‰ of the mass of the sludge VSS; further preferably, the mass ratio of the amylase and the liquefaction enzyme is 1:2 to 1:3.

[0022] The dehydration unit in the present invention is a conventional plate-and-frame, bag-type, filter-press and other dehydration equipment, so that the moisture content of the sludge after dehydration is not higher than 85%.

[0023] Preferably, the dehydration unit of the present invention does not require the addition of flocculating agents and / or flocculating aids.

[0024] The invention also provides a sludge utilization process method based on the sludge utilization system.

[0025] Preferably, the sludge resource utilization process comprises the following steps:

[0026] (1) The excess sludge in the sludge treatment enters the sludge concentration unit for concentration to obtain concentrated sludge;

[0027] (2) The concentrated sludge obtained in step (1) enters a pipeline ultrasonic unit for ultrasonic treatment to obtain pretreated sludge;

[0028] (3) the pretreated sludge obtained in step (2) enters a degradation unit, and organic matter in the pretreated sludge is degraded under the action of alkali and enzymes to obtain deeply treated sludge;

[0029] (4) The deep-treated sludge obtained in step (3) enters a dehydration unit and is dehydrated in the absence of a flocculant and / or a flocculant aid to obtain dehydrated sludge and filtrate;

[0030] (5) The filtrate obtained in step (4) is used as a carbon source in a sewage treatment system.

[0031] Preferably, the residual sludge in step (1) is the sludge in the sludge storage tank, and the moisture content of the sludge is 95-98%.

[0032] Preferably, the concentrated sludge in step (1) has a moisture content of 90-94%.

[0033] Preferably, the ultrasonic treatment in step (2) is: intensity 2-4w / mL, time 10-20min.

[0034] Preferably, the degradation conditions in step (3) are: temperature 40-70° C., reaction time 30-120 min.

[0035] Preferably, in step (3), the alkali is sodium hydroxide and / or calcium oxide. Further preferably, the alkali is sodium hydroxide and calcium oxide in a mass ratio of 1:1 to 10:1.

[0036] Preferably, in step (3), the enzymes are amylase and liquefaction enzyme; and the added amount of the enzymes is 1-5‰ of the mass of the sludge VSS.

[0037] Further preferably, the mass ratio of the amylase to the liquefaction enzyme is 1:2 to 1:3.

[0038] Preferably, the order of adding the alkali and the enzyme in step (3) is: adding the alkali, adjusting the pH value of the pretreated sludge to 8-12, and then adding the enzyme.

[0039] Preferably, the moisture content of the dewatered sludge in step (4) is not higher than 85%.

[0040] Sludge moisture content: The percentage of the weight of water contained in the sludge to the total weight of the sludge is called the sludge moisture content.

[0041] Sludge VSS: The mass of sludge solids volatilized after burning at 600℃ is volatile suspended solids. VSS can roughly represent the content of organic matter in sludge solids.

[0042] Sludge storage tank: It is a conventional sludge storage tank in a sewage treatment plant, which can be connected to the secondary sedimentation tank.

[0043] The beneficial effects of the present invention are:

[0044] (1) The sludge utilization system and process method of the present invention are improved on the basis of existing sewage treatment facilities, and the combined treatment of ultrasound + alkali + enzyme is used to effectively improve the dewatering performance of the sludge. There is no need to add flocculants and / or flocculants, thus avoiding the dependence of subsequent dehydration units on flocculants and / or flocculants, and greatly reducing the cost of sludge treatment.

[0045] (2) Compared with the prior art, the present invention can reduce the amount of sludge by more than 30% by using the combined treatment of ultrasound + alkali + enzyme, reduce the equipment investment of the sludge dehydration unit, and reduce the disposal cost of sludge dehydration.

[0046] (3) Compared with the prior art, the COD concentration of the filtrate produced by the dehydration unit of the present invention is increased by more than 25%, and there is no influence of flocculating agents, so it can be reused in the sewage treatment system as an auxiliary carbon source, reducing the cost of purchasing carbon source agents.

[0047] (4) The sludge utilization system of the present invention has a small footprint and requires little investment, and is more in line with the operational requirements of existing sewage treatment plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic diagram of a sludge utilization system of the present invention;

[0049] Among them, 1. Sludge concentration unit, 2. Pipeline ultrasonic unit, 3. Degradation unit, 4. Dehydration unit.

[0050] Figure 2 It is a schematic diagram of the structure of one or more embodiments of the sludge utilization system and process method of the present invention. DETAILED DESCRIPTION

[0051] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0052] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing specific embodiments rather than for limiting the scope of protection of the present invention.

[0053] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those of ordinary skill in the art to which the present invention belongs. The enzymes are all common commercial products, wherein the amylase has an enzyme activity of 2000U / g; the liquefaction enzyme has an enzyme activity of 10000U / g. The enzyme preparation manufacturer can be, for example, Shandong Longkote Enzyme Preparation Co., Ltd., or other enzyme preparation professional manufacturers that meet the corresponding requirements.

[0054] A sludge utilization system, such as Figure 1 As shown, it includes a sludge concentration unit 1, a pipeline ultrasonic unit 2, a degradation unit 3 and a dehydration unit 4 which are connected in sequence;

[0055] The sludge concentration unit 1 is configured to: concentrate the stored sludge;

[0056] The pipeline ultrasonic unit 2 is configured to: perform ultrasonic treatment on the sludge in the pipeline;

[0057] The degradation unit 3 is configured to: degrade organic matter in the sludge;

[0058] The dehydration unit 4 is configured to dehydrate the sludge.

[0059] The main body of the sludge concentration unit 1 in the present invention may be a pool or a tank, for example, the sludge concentration unit 1 may be a sludge concentration pool or a sludge concentration tank; preferably, the volume of the sludge concentration unit does not exceed 50% of the volume of the sludge storage pool.

[0060] The upper liquid level of the sludge concentration unit described in the present application is lower than the upper liquid level of the sludge storage tank, and the lower liquid level of the sludge concentration unit is lower than the lower liquid level of the sludge storage tank, so that a potential energy difference is formed between the two. At the same time, a valve is provided between the sludge concentration unit and the sludge storage tank to further squeeze the sludge.

[0061] Preferably, the sludge concentration unit 1 is provided with a stirring device.

[0062] The main body of the pipeline ultrasonic unit 2 in the present invention is a pipeline, and an ultrasonic device is arranged in the pipeline. The pipeline in the present invention can also be replaced by a container (such as a tower or a tank) with a length-to-diameter ratio greater than 2.

[0063] Preferably, the intensity of the pipeline ultrasonic unit 2 is 2-4w / mL, and the residence time is 10-20min.

[0064] The main body of the degradation unit 3 in the present invention may be a pool, a tank or a tower, for example, the degradation unit 3 may be a degradation pool, a degradation tank or a degradation tower, etc. Preferably, the degradation unit 3 is provided with a stirring device.

[0065] The degradation unit 3 of the present invention is provided with at least one feeding port for adding alkali, amylase and liquefaction enzyme.

[0066] The alkali is sodium hydroxide and / or calcium oxide. Preferably, the alkali is sodium hydroxide and calcium oxide in a mass ratio of 1:1 to 10:1.

[0067] The addition amount of the amylase and the liquefaction enzyme is 1-5‰ of the mass of the sludge VSS; preferably, the mass ratio of the amylase to the liquefaction enzyme is 1:2 to 1:3.

[0068] The dehydration unit 4 in the present invention is a conventional plate-and-frame, bag-type, filter-press or other dehydration equipment, so that the content of the dehydrated sludge is not higher than 85%.

[0069] Preferably, the dehydration unit 4 of the present invention does not need to add flocculating agents and / or flocculating aids.

[0070] The invention also provides a sludge utilization process method based on the sludge utilization system.

[0071] Specifically, the sludge utilization process comprises the following steps:

[0072] (1) The excess sludge in the sludge treatment enters the sludge concentration unit 1 and is concentrated to obtain concentrated sludge;

[0073] (2) The concentrated sludge obtained in step (1) enters the pipeline ultrasonic unit 2 for ultrasonic treatment to obtain pretreated sludge;

[0074] (3) The pretreated sludge obtained in step (2) enters the degradation unit 3, and the organic matter in the pretreated sludge is degraded under the action of alkali and enzyme to obtain deep-treated sludge;

[0075] (4) The deep-treated sludge obtained in step (3) enters the dehydration unit 4 and is dehydrated in the absence of a flocculant and / or a flocculant aid to obtain dehydrated sludge and filtrate;

[0076] (5) The filtrate obtained in step (4) is used as a carbon source in a sewage treatment system to realize resource utilization of organic matter.

[0077] Preferably, the residual sludge in step (1) is the sludge in the sludge storage tank, and the moisture content of the sludge is 95-98%.

[0078] Preferably, the concentrated sludge in step (1) has a moisture content of 90-94%.

[0079] Preferably, the ultrasonic treatment in step (2) is: intensity 2-4w / mL, time 10-20min.

[0080] Preferably, the degradation conditions in step (3) are: temperature 40-70° C., reaction time 30-120 min.

[0081] Preferably, in step (3), the alkali is sodium hydroxide and / or calcium oxide. Further preferably, the alkali is sodium hydroxide and calcium oxide in a mass ratio of 1:1 to 10:1.

[0082] Preferably, in step (3), the enzymes are amylase and liquefaction enzyme; and the added amount of the enzymes is 1-5‰ of the mass of the sludge VSS.

[0083] Further preferably, the mass ratio of the amylase to the liquefaction enzyme is 1:2 to 1:3.

[0084] Preferably, the order of adding the alkali and the enzyme in step (3) is: adding the alkali, adjusting the pH value of the pretreated sludge to 8-12, and then adding the enzyme.

[0085] Preferably, the sludge moisture content of the sludge in step (4) is not higher than 60%.

[0086] The following is an example of a sewage treatment company owned by the applicant, which adopts A 2 O process, sewage treatment capacity is 100,000 m 3 / d, the sludge water content of the sludge storage tank is 98.2%, which is converted to 80% water content sludge after dehydration, and the annual output is 60,000 tons. After improving the sludge treatment module using the sludge utilization system and its process method of the present invention, the obtained sewage treatment system is exemplarily shown as follows Figure 2 described.

[0087] Figure 2 The schematic diagram of the structure of one or more embodiments of the sludge utilization system of the present invention is applied. The system includes a sludge carbon source extraction system and a sewage treatment system. The sludge carbon source extraction system includes: a sludge storage tank, a sludge concentration tank, an ultrasonic pipeline, a thermal alkaline hydrolysis reaction tank and a centrifugal dehydration device, etc. The sewage treatment system includes A 2 O reaction tank and secondary sedimentation tank.

[0088] The present invention leads a bypass in the sludge storage tank in the sludge treatment process of the existing sewage treatment plant, and transports the sludge to the sludge concentration tank. The sludge enters the sludge thermal alkaline hydrolysis unit after pipeline-assisted ultrasonic treatment from the sludge concentration tank, and then enters the sludge solid-liquid separation unit for solid-liquid separation. The separated filtrate can be reused in the sewage treatment system as an auxiliary carbon source, and the separated sludge can be returned to the sludge dehydration system for further dehydration before being transported out.

[0089] Working principle of sludge compression tank (sludge thickening tank): by changing the tank capacity, valve opening, liquid level and tank bottom position, and utilizing the volume difference, weight difference, liquid level difference, etc. formed between the sludge storage tank and the sludge compression tank, the sludge is further dehydrated during the transportation process from the sludge storage tank to the sludge compression tank. The moisture content of the sludge discharged from the sludge compression tank is 94-90% (the sludge with this moisture content is the most suitable concentration for sludge thermal alkaline hydrolysis to prevent process blockage, and the efficiency of extracting carbon source by sludge thermal alkaline hydrolysis is high);

[0090] The volume of the sludge compression tank is smaller than that of the sludge storage tank, which can form a volume difference and a weight difference; and the liquid level of the sludge compression tank is lower than that of the sludge storage tank, which can form a potential energy difference; a valve is provided between the sludge storage tank and the sludge compression tank, which can further squeeze the sludge, and the sludge compression tank is provided with a stirring device. Preferably, the bottom of the sludge compression tank can be set lower than the bottom of the sludge storage tank, and the volume of the sludge compression tank is ≤0.5 times the volume of the sludge storage tank.

[0091] The intensity of pipeline ultrasound is 2-4w / mL, and the residence time is 10-20min. The residence time is adjusted by setting the length and diameter of the pipeline.

[0092] The sludge thermal alkaline hydrolysis unit is equipped with a stirring device. Alkali solution, amylase and liquefaction enzyme need to be added during operation. The alkali solution is used to adjust the pH range of the sludge to 8-12. The liquid alkali can be one or two of sodium hydroxide and calcium oxide. The ratio of sodium hydroxide to calcium oxide is 1:1 to 10:1. The amount of amylase and liquefaction enzyme added is 1-5‰ of the sludge VSS mass. The temperature is 40-70 degrees Celsius and the reaction time is 30-120 minutes.

[0093] The sludge thermal alkaline hydrolysis, amylase and liquefaction enzyme can be integrated into one reaction device, which reduces the process flow; the activity of amylase and liquefaction enzyme can be guaranteed by setting a suitable pH range, and at the same time, the system temperature can be used to simultaneously play the optimal physicochemical degradation and enzymatic degradation of organic matter by thermal alkaline hydrolysis, amylase and liquefaction enzyme, thus playing a triple degradation role.

[0094] Example 1

[0095] The volume of the sludge compression tank is 1 / 2 of the sludge storage tank, and the moisture content of the sludge after the sludge compression tank is 90%; the residence time of pipeline ultrasound is 20min, and the ultrasound intensity is 2w / ml; the reaction time of sludge degradation is 120min, the temperature is 40℃, the pH is 11.8, the alkali is sodium hydroxide, the dosage of liquefaction enzyme and amylase is 5‰ of the sludge VSS mass, and the mass ratio of liquefaction enzyme to amylase is 1:3; after solid-liquid separation, the COD concentration in the filtrate is 35200mg / L mg / L, the sludge moisture content is 83%, and the sludge volume is half of the sludge volume with a moisture content of 90%.

[0096] Example 2

[0097] The volume of the sludge compression tank is 1 / 4 of the sludge storage tank, and the moisture content of the sludge after the sludge compression tank is 94%; the residence time of pipeline ultrasound is 10min, and the ultrasound intensity is 4w / ml; the reaction time of sludge degradation is 30min, the temperature is 70℃, the pH is 8.1, the alkali is sodium hydroxide, the dosage of liquefaction enzyme and amylase is 1‰ of the sludge VSS mass, and the mass ratio of liquefaction enzyme and amylase is 1:8; after solid-liquid separation, the COD concentration in the filtrate is 41210mg / L, the sludge moisture content is 82%, and the sludge volume is one-third of the sludge volume with a moisture content of 94%.

[0098] Example 3

[0099] The volume of the sludge compression tank is 1 / 3 of the sludge storage tank, and the moisture content of the sludge after the sludge compression tank is 92%; the residence time of pipeline ultrasound is 15min, and the ultrasound intensity is 3w / ml; the reaction time of sludge degradation is 60min, the temperature is 50℃, the pH is 10, the alkali is sodium hydroxide and calcium oxide with a mass ratio of 5:1, the dosage of liquefaction enzyme and amylase is 2‰ of the sludge VSS mass, and the mass ratio of liquefaction enzyme and amylase is 1:5; after solid-liquid separation, the COD concentration in the filtrate is 26720mg / L, the sludge moisture content is 85%, and the sludge volume is half of the volume of sludge with a moisture content of 92%.

[0100] Comparative Example 1

[0101] The volume of the sludge compression tank is 1 / 3 of the sludge storage tank, and the moisture content of the sludge after the sludge compression tank is 92%; the pipeline ultrasound is not turned on; the reaction time of sludge degradation is 60min, the temperature is 50℃, the pH is 10.0, the alkali is sodium hydroxide and calcium oxide in a mass ratio of 5:1, the dosage of liquefaction enzyme and amylase is 2‰ of the sludge VSS mass, the COD concentration in the filtrate after solid-liquid separation is 8300mg / L, the sludge moisture content is 86%, and the sludge volume is two-fifths of the volume of sludge with a moisture content of 92%.

[0102] Comparative Example 2

[0103] The volume of the sludge compression tank is 1 / 3 of the sludge storage tank, and the moisture content of the sludge after the sludge compression tank is 92%; the residence time of pipeline ultrasound is 15min, and the ultrasound intensity is 3w / ml; the reaction time of sludge degradation is 60min, the temperature is 50℃, the pH is 10, the alkali is sodium hydroxide and calcium oxide with a mass ratio of 5:1, the dosage of liquefaction enzyme and amylase is 2‰ of the mass of sludge VSS, and the mass ratio of liquefaction enzyme and amylase is 1:1; after solid-liquid separation, the COD concentration in the filtrate after solid-liquid separation is 12040mg / L, the moisture content of the sludge is 87.2%, and the sludge volume is two-fifths of the volume of sludge with a moisture content of 92%.

[0104] Comparative Example 3

[0105] In the conventional sludge treatment process, the residual sludge in the sludge storage tank (water content is about 98%) is added with flocculants for solid-liquid separation. The COD concentration in the filtrate after solid-liquid separation is 538 mg / L, the sludge water content is 85%, and the sludge volume is three-quarters of the volume of sludge with a water content of 98%.

[0106] When the separated filtrate is reused in the sewage treatment system as an auxiliary carbon source, a multi-point addition method is adopted to add the anaerobic tank and the anoxic tank respectively, wherein the addition position of the anaerobic tank is the center point of the anaerobic tank, and the addition position of the anoxic tank is the water inlet of the anoxic tank, and the addition ratio of the anaerobic tank to the anoxic tank is 2:1 to 3:1. Preferably, when the filtrate is used as an auxiliary carbon source, the C / N is 2.9-5, and more preferably 2.9-3.2. Compared with conventional carbon sources (C / N=4-5), the amount of the filtrate added as an auxiliary carbon source in the present invention is greatly reduced, thereby reducing operating costs.

[0107] The reason why the filtrate is added at multiple points is that the B / C ratio of the carbon source extracted from the sludge is mostly 0.25-0.3, which cannot be better absorbed by microorganisms, but it is not an organic matter that is very difficult to be biodegraded; at the same time, the filtrate also contains a large amount of suspended matter, and the components of the suspended matter are mainly organic particles. Therefore, adding a part of the filtrate to the center point of the anaerobic tank can further anaerobically decompose the organic matter with a relatively low B / C and the organic matter in the suspended state. After experimental verification: the filtrate is used as an auxiliary carbon source. The retention time in the anaerobic tank is half of the hydraulic retention time of the anaerobic tank, and it can be decomposed to a carbon source that meets the biodegradability and can be absorbed by microorganisms. Therefore, the auxiliary carbon source after anaerobic flow into the anoxic tank. At this time, the filtrate can be used as an auxiliary carbon source. Added to the sewage treatment system again, it realizes the resource utilization of organic matter.

[0108] Among them, the B / C ratio is the ratio of BOD (biochemical oxygen demand) to COD (chemical oxygen demand). When BOD / COD is greater than 0.3, it is generally believed that the wastewater is biodegradable.

[0109] The above is a further description of the present invention in conjunction with specific embodiments, but these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

Claims

1. A sludge utilization system, characterized in that: It includes a sludge concentration unit, a pipeline ultrasonic unit, a degradation unit and a dehydration unit connected in sequence; The sludge concentration unit is configured to: concentrate the stored sludge; The pipeline ultrasonic unit is configured to: perform ultrasonic treatment on the sludge in the pipeline; The degradation unit is configured to: degrade organic matter in the sludge, wherein the degradation unit is provided with a feed port for adding alkali and enzymes, wherein the enzymes include amylase and liquefaction enzyme; The dehydration unit is configured to dehydrate the sludge.

2. The sludge utilization system according to claim 1, characterized in that: The alkali is sodium hydroxide and / or calcium oxide; preferably, the alkali is sodium hydroxide and calcium oxide in a mass ratio of 1:1 to 10:

1.

3. The sludge utilization system according to claim 1, characterized in that: The addition amount of the amylase and liquefaction enzyme is 1-5‰ of the mass of the sludge VSS.

4. The sludge utilization system according to claim 3, characterized in that: The mass ratio of the amylase to the liquefying enzyme is 1:2 to 1:

3.

5. A sludge utilization process method based on the sludge utilization system according to any one of claims 1 to 4.

6. The sludge utilization process according to claim 5, characterized in that: The following steps are involved: (1) The excess sludge in the sludge treatment enters the sludge concentration unit for concentration to obtain concentrated sludge; (2) The concentrated sludge obtained in step (1) enters a pipeline ultrasonic unit for ultrasonic treatment to obtain pretreated sludge; (3) the pretreated sludge obtained in step (2) enters a degradation unit, and organic matter in the pretreated sludge is degraded under the action of alkali and enzymes to obtain deeply treated sludge; (4) The deep-treated sludge obtained in step (3) enters a dehydration unit and is dehydrated in the absence of a flocculant and / or a flocculant aid to obtain dehydrated sludge and filtrate; (5) The filtrate obtained in step (4) is used as a carbon source in a sewage treatment system.

7. The sludge utilization process according to claim 6, characterized in that: The excess sludge in step (1) has a sludge moisture content of 95-98%; the concentrated sludge has a sludge moisture content of 90-94%.

8. The sludge utilization process according to claim 6, characterized in that: The ultrasonic treatment in step (2) is as follows: intensity 2-4w / mL, time 10-20min.

9. The sludge utilization process according to claim 6, characterized in that: The degradation conditions in step (3) are: temperature 40-70° C., reaction time 30-120 min.

10. The sludge utilization process according to claim 6, characterized in that: In step (3), the alkali is sodium hydroxide and / or calcium oxide, preferably, the alkali is sodium hydroxide and calcium oxide in a mass ratio of 1:1 to 10:1; In step (3), the enzymes are amylase and liquefaction enzyme, and the amount of the enzymes added is 1-5‰ of the mass of the sludge VSS; preferably, the mass ratio of the amylase to the liquefaction enzyme is 1:2 to 1:3; The order of adding the alkali and the enzyme in step (3) is: adding the alkali, adjusting the pH value of the pretreated sludge to 8-12, and then adding the enzyme.

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