Combined device for anaerobic digestion pretreatment of urban organic wastes

Abstract

The utility model discloses a combined device for anaerobic digestion pretreatment of urban organic wastes, and belongs to the technical field of urban organic waste treatment and recycling. Comprising a pretreatment pool I (1), a pretreatment pool II (2), an acidification pool (3), an anaerobic fermentation tank (4), a dehydrator (5), a biogas slurry pool (6) and a nitrosation pool (7). The residual sludge is treated in situ by using acidizing fluid and biogas slurry in the anaerobic digestion system, the hydrolysis process is accelerated, and anaerobic co-digestion is performed after the residual sludge and perishable wastes (kitchen waste, kitchen garbage, excrement and the like) are respectively pretreated, so that the stability of the anaerobic digestion system is improved. The device has the advantages of being green, economical, environment-friendly, convenient to operate continuously and the like, and has a good application prospect.

Description

Technical Field

[0001] The utility model belongs to the technical field of urban organic waste treatment and resource utilization, in particular to a combined device for pre-treatment of urban organic waste by anaerobic digestion. Background Art

[0002] Urban organic waste mainly includes restaurant waste, kitchen waste, residual sludge, urban feces, agricultural and trade waste, etc. This type of waste has a high organic content and can be reduced, converted into energy and resources through anaerobic digestion. However, perishable wastes such as restaurant waste, kitchen waste and feces have a fast hydrolysis and acidification rate, while the organic matter in residual sludge is mainly microbial intracellular substances, which has a slow hydrolysis and acidification rate, which seriously affects the co-fermentation rate of organic waste and multiple materials, resulting in problems such as long anaerobic digestion cycle, large fermentation tank area, and high investment.

[0003] The utility model utilizes the acidified liquid and biogas slurry in the anaerobic digestion system to treat the residual sludge in situ, accelerates the hydrolysis process, and simultaneously pre-treats the residual sludge and perishable waste (food waste, kitchen waste and feces, etc.) separately for anaerobic co-digestion, thereby improving the stability of the anaerobic digestion system. The utility model has the advantages of green economy, environmental friendliness, and convenience for continuous operation, and has a good application prospect. Utility Model Content

[0004] In view of the current problem of slow hydrolysis rate of multi-material co-digestion of urban organic waste, the present application provides a combined device for anaerobic digestion pre-treatment of urban organic waste, which is easy to operate, low in energy consumption, and green and environmentally friendly.

[0005] To achieve the above-mentioned purpose, the technical solution of the present application is a combined device for anaerobic digestion pretreatment of urban organic waste, which specifically comprises: a pretreatment tank 1 (1), a pretreatment tank 2 (2), an acidification tank (3), an anaerobic fermentation tank (4), a dehydrator (5), a biogas slurry tank (6), and a nitrite tank (7);

[0006] The bottom of the feed inlet of the pretreatment tank (1) is sloped, and the feed inlet is equipped with a baffle. A discharge pipe (1-2) and a discharge pipe (1-3) are arranged above the slope corresponding to the pretreatment tank (1). The discharge pipe (1-2) is connected with the nitrification tank (7) so that the subdigestion liquid of the nitrification tank (7) can enter the pretreatment tank (1) through the discharge pipe (1-2) and flush the slope. The discharge pipe (1-3) is connected with the acidification tank (3) so that the acidified liquid of the acidification tank (3) can enter the pretreatment tank (1) and flush the slope. The discharge port of the pretreatment tank (1) is connected with the acidification tank (3).

[0007] A slope 2 is provided at the bottom of the feed inlet of the second pretreatment tank (2), and the feed inlet is provided with a baffle 2; a discharge pipe 3 (2-2) is provided above the slope 2, and the discharge pipe 3 (2-2) is connected to the biogas tank (6) so that the biogas in the biogas tank (6) enters the second pretreatment tank (2) and flushes the slope 2; the discharge port of the second pretreatment tank (2) is connected to the acidification tank (3);

[0008] A heating coil 2 (3-3) is arranged in the acidification tank (3); the discharge port of the acidification tank (3) is connected to the anaerobic fermentation tank (4); the discharge port of the anaerobic fermentation tank (4) is connected to the feed port of the dehydrator (5); the liquid outlet of the dehydrator (5) is connected to the biogas slurry tank (6); and the discharge port of the biogas slurry tank (6) is connected to the nitrification tank (7).

[0009] The pretreatment tank 1 (1) is also equipped with a pH meter (1-4), a stirrer 1 (1-5), a thermometer 1 (1-6), and a heating coil 1 (1-7) is provided at the bottom of the pretreatment tank 1 (1);

[0010] The pretreatment tank 2 (2) is equipped with a stirrer 2 (2-3);

[0011] The acidification tank (3) is also equipped with a second thermometer (3-1), a third stirrer (3-2), and a second heating coil (3-3) is provided at the bottom of the acidification tank (3);

[0012] The nitrification tank (7) is also equipped with a thermometer three (7-1), a nitrite nitrogen monitor (7-2), and a stirrer four (7-3). The bottom of the nitrification tank (7) is also provided with a heating coil three (7-4) and an aeration pipe (7-5).

[0013] The main function of the pretreatment tank is to pre-treat the excess sludge generated by the municipal sewage treatment plant, and to use the acidified liquid of the acidification tank and the nitrite nitrogen of the nitrite tank to produce free nitrous acid to destroy the cell wall of the excess sludge, release the organic matter in the cell, and accelerate the rate of the hydrolysis stage of anaerobic digestion of the sludge. The baffle is only opened when feeding and closed at ordinary times. The liquid in the discharge pipe one is the nitrite liquid in the nitrite tank, and the discharge pipe two is the acidified liquid of the acidification tank. The liquid in the discharge pipe one and the discharge pipe two can flush the excess sludge remaining on the slope. The pH meter monitors the pH value of the material in the pretreatment tank one in real time, and controls the pH value of the material in the pretreatment tank to be within the range of 5.0 to 5.5 by the amount of the acidified liquid. The speed of the agitator is 60 to 100 rpm, and the material is fully stirred so that the acidified liquid, the nitrite liquid, and the excess sludge are fully homogenized, so that the excess sludge is fully in contact with the nitrous acid, and the cell wall of the excess sludge is better destroyed. Thermometer and heating coil jointly control the temperature of materials in pretreatment tank 1, maintaining the temperature at 25℃~35℃. A slope is provided in the pretreatment tank, and the slope surface is at an angle of 25~40° with the horizontal plane, so that the materials can flow to the bottom of the pretreatment tank by themselves. The residence time of materials in pretreatment tank 1 is 12~18h.

[0014] The main function of the pretreatment tank 2 is to pretreat one or more of the food waste, kitchen waste, leachate and feces. These materials are easy to hydrolyze and acidify, and do not need to be broken. They only need to be fully stirred and mixed and temporarily stored in the pretreatment tank 2. The baffle in the pretreatment tank 2 is only opened when feeding and closed at other times. The main function of the discharge pipe 3 is to use the biogas in the biogas tank to wash the residual materials on the slope. The agitator is 60 to 80 rpm to maintain the homogeneity of the materials in the pretreatment tank 2.

[0015] The main function of the acidification tank is to mix the materials in the pretreatment tank 1 and the pretreatment tank 2 and then perform hydrolysis and acidification. The stirring speed of the agitator is 60 to 80 rpm to fully mix the materials. In order to ensure the suitable temperature for the growth of hydrolysis and acidification bacteria, a heating coil and a thermometer are installed in the acidification tank to control the temperature of the materials in the tank to 30 to 35°C. The retention time of the materials in the acidification tank is 12 to 24 hours.

[0016] The main function of the nitrification tank is to nitrify the ammonia nitrogen in the biogas slurry and provide nitrite nitrogen for the pretreatment tank-pretreatment residual sludge. A heating coil and a thermometer are installed in the tank to control the temperature of the material in the tank to be in the range of 25-30°C to provide a suitable temperature for microorganisms. An aeration pipe is installed at the bottom of the tank, and air is used as the air source to provide oxygen for the microorganisms to carry out nitrification reactions. At the same time, the nitrite nitrogen monitor monitors the nitrite nitrogen concentration in real time to maintain the nitrite nitrogen at 200-600 mg / L.

[0017] The main function of the biogas pool is to temporarily store the biogas slurry from anaerobic digestion. Part of the biogas slurry is returned to the pre-treatment pool 2, and part of the biogas slurry is transported to the nitrification pool.

[0018] Due to the adoption of the above technical scheme, the utility model can achieve the following technical effects: the process and device are simple and easy to operate, green and environmentally friendly, and easy to operate and manage. The in-situ generation of free nitrous acid to break down the remaining and perishable waste for anaerobic co-digestion can shorten the anaerobic digestion residence time, reduce the volume of the anaerobic fermentation tank, and make urban organic waste a resource. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a diagram of a combined device for anaerobic digestion pre-treatment of urban organic waste.

[0020] Figure 1Description of the serial numbers: 1 Pretreatment tank one, 1-1 baffle one, 1-2 drain pipe one, 1-3 drain pipe two, 1-4 pH meter, 1-5 stirrer one, 1-6 thermometer one, 1-7 heating coil one, 1-8 slope one, 2 Pretreatment tank two, 2-1 baffle two, 2-2 drain pipe three, 2-3 stirrer two, 2-4 slope two, 3 acidification tank, 3-1 thermometer two, 3-2 stirrer three, 3-3 heating coil two, 4 anaerobic fermentation tank, 5 dehydrator, 6 sludge tank, 7 nitrite tank, 7-1 thermometer three, 7-2 nitrite nitrogen monitor, 7-3 stirrer four, 7-4 heating coil three, 7-5 aeration pipe. DETAILED DESCRIPTION

[0021] The following is combined with Figure 1 The utility model is further described in detail with the following specific embodiments: the application is further described with this example. However, the utility model is not limited to the following embodiments.

[0022] Example 1

[0023] This embodiment provides a combined device for anaerobic digestion pre-treatment of urban organic waste, characterized by specifically comprising:

[0024] Figure 1 Description of the serial numbers: 1 Pretreatment tank one, 1-1 baffle one, 1-2 drain pipe one, 1-3 drain pipe two, 1-4 pH meter, 1-5 stirrer one, 1-6 thermometer one, 1-7 heating coil one, 1-8 slope one, 2 Pretreatment tank two, 2-1 baffle two, 2-2 drain pipe three, 2-3 stirrer two, 2-4 slope two, 3 acidification tank, 3-1 thermometer two, 3-2 stirrer three, 3-3 heating coil two, 4 anaerobic fermentation tank, 5 dehydrator, 6 sludge tank, 7 nitrite tank, 7-1 thermometer three, 7-2 nitrite nitrogen monitor, 7-3 stirrer four, 7-4 heating coil three, 7-5 aeration pipe.

[0025] The above-mentioned combined device for anaerobic digestion pretreatment of urban organic waste has the following specific working steps:

[0026] (1) After the transport vehicle arrives, open the baffle 1-2 of the pretreatment tank 1, and dump the remaining sludge directly onto the slope 1-8. Most of the remaining sludge slides directly to the bottom of the tank. Open the drain pipe 1-2 and the drain pipe 1-3 to wash the remaining remaining sludge on the slope. Turn on the agitator 1-5, adjust the speed to 60-100 rpm, stir the materials thoroughly, and mix the remaining sludge, acidified liquid and nitrite liquid thoroughly. Control the amount of acidified liquid added to the drain pipe 1-2 to maintain the pH value at 5.0-5.5. The heating coil 1-7 installed inside the tank is preferably a steam heat source to heat the materials in the tank. The thermometer 1-6 monitors the temperature in real time and maintains the temperature at 25°C-35°C. The material residence time in the pretreatment tank 1 is 12-18h.

[0027] (2) Pretreatment tank 2 mainly receives food waste, kitchen waste, leachate and feces. After the materials arrive, the baffle 2-1 is opened, and the materials flow to the bottom of the tank along the slope 1-8. The liquid discharge pipe 3 2-2 is opened, and the slope 2-4 is flushed with biogas slurry. After all the materials reach the bottom of the tank, the baffle is closed and the agitator 2-3 is turned on to fully stir the materials. The speed of the agitator is 60 to 80 rpm.

[0028] (3) Acidification tank three mixes the pretreated material in step (1) and the pretreated material in step (2) for hydrolysis and acidification. The agitator 3-2 stirs at a speed of 60 to 80 rpm to fully mix the materials. The steam heating coil 3-3 on the inner wall of the tank heats the materials in the tank, and the thermometer 3-1 monitors in real time to maintain the material temperature at 30 to 35°C. The residence time of the materials in the acidification tank is 12 to 24 hours. Part of the materials in the acidification tank three are returned to the pretreatment tank one as acidification liquid, and most of the materials are transported to the anaerobic fermentation tank.

[0029] (4) The material after anaerobic digestion in the anaerobic fermentation tank is transported to the dehydrator 5, and the dehydrated biogas residue is used for fertilizer production. The biogas liquid flows by gravity to the biogas liquid pool 6 for temporary storage. Most of the biogas liquid is transported to the nitrite pool 7, and a small part of the biogas liquid is transported to the pretreatment pool 2.

[0030] (5) The thermometer in the nitrification tank 7 monitors the temperature of the material in the tank in real time. The steam heating coil 7-4 is installed on the inner wall of the tank to heat the material in the tank and maintain the temperature of the material in the tank in the range of 25-30°C. The nitrite nitrogen monitor 7-2 monitors the nitrite nitrogen concentration in real time. The aeration pipe 7-5 uses air aeration to maintain the nitrification environment for microorganisms, and finally maintains the nitrite nitrogen at 200-600 mg / L.

[0031] The above is only a preferred specific implementation method of the utility model, but the protection scope of the utility model is not limited to it. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and utility model concept of the utility model within the technical scope disclosed by the utility model, which should be covered by the protection scope of the utility model.

Claims

1. A combined device for anaerobic digestion pretreatment of urban organic waste, characterized in that: Specifically include: Pretreatment tank one (1), pretreatment tank two (2), acidification tank (3), anaerobic fermentation tank (4), dehydrator (5), biogas slurry tank (6), nitrite tank (7); The bottom of the feed inlet of the pretreatment tank (1) is sloped, and the feed inlet is equipped with a baffle. A discharge pipe (1-2) and a discharge pipe (1-3) are arranged above the slope corresponding to the pretreatment tank (1). The discharge pipe (1-2) is connected with the nitrification tank (7) so that the subdigestion liquid of the nitrification tank (7) can enter the pretreatment tank (1) through the discharge pipe (1-2) and flush the slope. The discharge pipe (1-3) is connected with the acidification tank (3) so that the acidified liquid of the acidification tank (3) can enter the pretreatment tank (1) and flush the slope. The discharge port of the pretreatment tank (1) is connected with the acidification tank (3). A slope 2 is provided at the bottom of the feed inlet of the second pretreatment tank (2), and the feed inlet is provided with a baffle 2; a discharge pipe 3 (2-2) is provided above the slope 2, and the discharge pipe 3 (2-2) is connected to the biogas tank (6) so that the biogas in the biogas tank (6) enters the second pretreatment tank (2) and flushes the slope 2; the discharge port of the second pretreatment tank (2) is connected to the acidification tank (3); A heating coil 2 (3-3) is arranged in the acidification tank (3); the discharge port of the acidification tank (3) is connected to the anaerobic fermentation tank (4); the discharge port of the anaerobic fermentation tank (4) is connected to the feed port of the dehydrator (5); the liquid outlet of the dehydrator (5) is connected to the biogas slurry tank (6); and the discharge port of the biogas slurry tank (6) is connected to the nitrification tank (7).

2. A combined device for anaerobic digestion pretreatment of urban organic waste according to claim 1, characterized in that: The pretreatment tank (1) is also equipped with a pH meter (1-4), a stirrer (1-5), and a thermometer (1-6). A heating coil (1-7) is provided at the bottom of the pretreatment tank (1).

3. A combined device for anaerobic digestion pretreatment of urban organic waste according to claim 1, characterized in that: The pretreatment tank 2 (2) is equipped with a stirrer 2 (2-3).

4. A combined device for anaerobic digestion pretreatment of urban organic waste according to claim 1, characterized in that: The acidification tank (3) is also equipped with a second thermometer (3-1) and a third stirrer (3-2). The bottom of the acidification tank (3) is equipped with a second heating coil (3-3).

5. A combined device for anaerobic digestion pretreatment of urban organic waste according to claim 1, characterized in that: The nitrification tank (7) is also equipped with a thermometer three (7-1), a nitrite nitrogen monitor (7-2), and a stirrer four (7-3). The bottom of the nitrification tank (7) is also provided with a heating coil three (7-4) and an aeration pipe (7-5).

6. A combined device for anaerobic digestion pretreatment of urban organic waste according to claim 1, characterized in that: The pretreatment tank 1 pre-treats the residual sludge produced by the municipal sewage treatment plant; the pre-treatment tank 2 pre-treats restaurant waste, kitchen waste, leachate and fecal and perishable waste.

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