CN103803770A - High-temperature microaerobic-anaerobic digestion device and method for organic sludge - Google Patents

Abstract

The invention discloses a high-temperature micro-aerobic-anaerobic digestion device and method for organic sludge. Firstly, the organic sludge undergoes a high-temperature micro-aerobic digestion process. Enter the pH adjustment tank through the pipeline, put lye into the pH adjustment tank to adjust the pH of the material in the tank, and the sludge stays in the tank for 3 to 5 hours to release the dissolved oxygen in the sludge; then the sludge is pumped into the anaerobic The oxygen fermentation reactor stays for 6-20 days to complete the anaerobic digestion process. The first half of the organic sludge digestion process of the present invention is a self-heating high-temperature micro-aerobic digestion process rather than a self-heating high-temperature aerobic digestion process; the amount of air supplied by the self-heating high-temperature micro-aerobic digestion process is limited, and the oxygen Under restricted conditions, it is easy to produce VFA, and VFA is easy to produce methane under anaerobic conditions; this is not only conducive to the further digestion of sludge in the second half of the anaerobic digestion process to produce methane, but also reduces the amount of aeration and energy consumption. consumption.

Description

High-temperature micro-aerobic-anaerobic digestion device and method for organic sludge

technical field

The invention relates to the field of solid waste treatment, in particular to a high-temperature micro-aerobic-anaerobic digestion device and method for organic sludge.

Background technique

With the development of social economy and urbanization in our country, the amount of urban sewage is constantly increasing. It is predicted that in 2010 China's urban sewage discharge will reach 44 billion m ³ /d; in 2020 it will reach 53.6 billion m ³ /d. Although China's sewage treatment capacity and treatment rate are not high at present, urban sewage treatment plants discharge about 300,000 tons of dry sludge every year, and it is also growing at a rate of 10% per year ^[2] . my country's existing sewage treatment plants have the phenomenon of heavy water and light mud. A large part of the sludge has not been stabilized and harmless treated, and the sludge treatment facilities have not been effectively operated. The sludge has not been properly disposed of, resulting in environmental pollution. The long-term sustainable development of urban sewage plants. At present, how to effectively deal with municipal sludge is the most important and complicated problem faced in the field of sewage (waste) water treatment in the international scope.

Sludge digestion technology achieves the stabilization and harmlessness of sludge through the degradation of organic matter by microorganisms. The existing sludge digestion processes mainly include traditional aerobic digestion process, conventional mesophilic anaerobic digestion process, two-stage anaerobic digestion process, anoxic/aerobic digestion process, self-heating high-temperature aerobic digestion process, and two-stage high-temperature aerobic digestion process. /Mesophilic anaerobic digestion process.

The two-stage high-temperature aerobic/medium-temperature anaerobic digestion process combines the self-heating high-temperature aerobic digestion process with the medium-temperature anaerobic digestion process. First, the sludge is pretreated with a high-load self-heating high-temperature aerobic digestion process system. Then enter the medium temperature anaerobic reactor. This process can significantly improve the removal rate of pathogenic bacteria and the stability of the subsequent mesophilic anaerobic digestion operation, but this process is still in the experimental stage.

For example, the Chinese patent document CN 100486722C (application number 200610087577.6) discloses a two-stage semi-solid organic waste digestion process for fertilization and gas production. The semi-solid organic waste is digested under high-temperature micro-aerobic and mesophilic anaerobic conditions in series. Kill pathogenic bacteria, pre-decompose waste, decompose waste and generate biogas in the middle temperature stage, and the final product is rich in humic acid, nitrogen, phosphorus, and potassium; the specific steps are firstly semi-solid organic waste enters the high-temperature micro-aerobic digestion unit, Air is introduced into the high-temperature micro-aerobic digestion unit to maintain the dissolved oxygen concentration of the semi-solid waste in the high-temperature micro-aerobic digestion unit at 0.1-0.8mg/L, and the semi-solid organic waste begins to decompose under the action of microorganisms, consumes oxygen and releases the reaction Heat, the temperature of the digestive juice can reach above 55°C, maintain the temperature of the digestive liquid at 55°C-70°C and keep it for 1-3 days; the high-temperature fluid static heat exchanger discharged from the high-temperature micro-aerobic digestion unit cools down and enters the second stage of medium temperature In the anaerobic digestion unit, the waste heat recovered by the heat exchanger uses circulating water as the carrier to keep the mesophilic anaerobic digestion unit warm; The easily degradable substances are continuously converted into biogas. After 15 to 20 days in the second stage, the final products of digestion are discharged from the mesophilic anaerobic digestion unit and enter the sedimentation storage for standby or sale.

The high-temperature micro-aerobic stage of the preparation process has the problem of difficult oxygenation. In actual operation, under the high temperature condition of 55°C to 70°C, the dissolved oxygen concentration is very low, and the oxygen mass transfer efficiency of the semi-solid material is low, and the oxygenation is very difficult. Therefore, it is difficult for this method to reach the aerobic state according to the content disclosed in the text. If the aerobic condition cannot be reached, the first stage cannot release enough heat, and the organic solids are easy to anaerobic acidification, and the pH value of the sludge flowing out from the first stage is relatively low. low, leading to the inability to produce biogas in the second stage anaerobic digestion process, and the anaerobic digestion residence time is long; in addition, according to the content currently disclosed in this method, it is difficult to control the temperature of mesophilic anaerobic digestion to the target temperature, because the heat exchanger recovers The waste heat is low (that is, the temperature difference between 55°C ~ 70°C and 35°C ~ 40°C is very small), and it is difficult to achieve the heat preservation effect; due to the long residence time and large volume of the anaerobic pool, the heat preservation effect is achieved through the heat exchanger in winter Just lower.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-temperature micro-aerobic-anaerobic digestion device and method for organic sludge.

The technical solution for realizing the object of the present invention is a high-temperature micro-aerobic-anaerobic digestion device for organic sludge, including a high-temperature aerobic reactor and anaerobic fermentation reactor, and also includes a pH value adjustment tank; the high-temperature aerobic reactor It is a self-heating high-temperature micro-aerobic reactor; the pH adjustment tank is set between the high-temperature micro-aerobic reactor and the anaerobic fermentation reactor, and the outlet of the self-heating high-temperature micro-aerobic reactor is connected to the pH value through a pipeline. The adjustment tanks are communicated, and the pH value adjustment tanks are communicated with the feed port of the anaerobic fermentation reactor through pipelines and pumps.

The self-heating high-temperature micro-aerobic reactor includes a reaction tank, a sludge return system, an aeration system, a temperature sensor, and a gas absorption treatment device; the sludge return system is arranged outside the reaction tank, including a lower pipeline, a sludge return The pump and the upper pipeline; the lower pipeline, the sludge return pump, the upper pipeline and the reaction tank form a connected circuit; the aeration system includes an aeration pipe, an aeration head, a pressure gauge, and the aeration pipe is arranged in the reaction tank the bottom of the reaction tank; one temperature sensor is installed on the upper part, one middle part and one lower part of the reaction tank; the gas absorption treatment device is arranged on the top of the reaction tank and communicates with the inside of the reaction tank through a pipeline.

The anaerobic fermentation reactor includes a reaction tank, a stirrer, a gas collection filter, a temperature sensor, a gas sampling pipe and a circulating water pipeline. The agitator includes a motor, a rod shaft and stirring blades. The motor is fixed above the reaction tank. The rod shaft penetrates into the reaction tank from top to bottom. The stirring blades are arranged in two layers on the rod shaft. It is arranged at the bottom of the reaction tank, and the upper stirring paddle is arranged at the middle of the effective water depth in the reaction tank.

The circulating water pipeline is arranged at the bottom of the reaction tank and connected to the boiler through the pipeline, and the gas stove of the boiler is connected with the gas outlet of the gas collection filter through the pipeline.

A method for digestion of organic sludge high-temperature micro-aerobic-anaerobic digestion device as described above, comprising the following steps:

① The domestication of the strains, the domestication of the strains is carried out in the reaction tank of the self-heating high-temperature micro-aerobic reactor, and 1/4 to 1/2 of the seed sludge containing the strains obtained from the domestication is left in the reaction tank.

②High-temperature micro-aerobic digestion process of organic sludge; turn on the sludge delivery pump and send organic sludge into the reaction tank of the self-heating high-temperature micro-aerobic reactor. volume; open the sludge return system and aeration system, the organic sludge starts the high-temperature micro-aerobic digestion process, and the sludge stays in the self-heating high-temperature micro-aerobic reactor for 2 to 3 days to complete the high-temperature micro-aerobic digestion process; digestion The temperature is maintained between 45°C and 65°C.

After the high-temperature micro-aerobic digestion is completed, the digested sludge enters the pH value adjustment tank from the outlet through the pipeline, and puts lye into the pH value adjustment tank to adjust the pH value of the material in the pH value adjustment tank to 6.8~ Between 7.2, the sludge after the pH value is adjusted stays in the tank for 3 to 5 hours to release the dissolved oxygen in the sludge.

③ Anaerobic digestion process of organic sludge; Step ② The sludge that releases dissolved oxygen and undergoes high-temperature micro-aerobic digestion is pumped into the anaerobic fermentation reactor to stay for 6-20 days to complete the anaerobic digestion process, and the discharged sludge is mechanically dehydrated directly for agricultural use.

In the above step ② during the high-temperature micro-aerobic digestion process of the organic sludge, the oxidation-reduction potential ORP in the reaction tank of the self-heating high-temperature micro-aerobic reactor is 0-100mv.

The anaerobic digestion process of the above step ③ organic sludge is a mesophilic anaerobic digestion process; the mesophilic anaerobic temperature is 33°C-35°C, and the sludge stays in the anaerobic fermentation reactor for 10-20 days to complete the anaerobic digestion process.

Further, if the temperature of the sludge flowing out after self-heating high-temperature micro-aerobic digestion exceeds 60°C, the sludge after high-temperature micro-aerobic digestion should be extended for 0 to 40 minutes in the pH adjustment tank to dissipate heat to the medium-temperature anaerobic temperature range; if the temperature of the anaerobic tank does not reach the range of the mesophilic anaerobic temperature, reduce the aeration volume of the high-temperature micro-aerobic digestion and increase the sludge backflow to give mechanical heat, so that the temperature of the high-temperature micro-aerobic digestion reaches 50 ° C ~ 60 ° C , to ensure the medium temperature of the anaerobic tank.

Optionally, the anaerobic digestion process of step ③ organic sludge is a high-temperature anaerobic digestion process; the temperature of high-temperature anaerobic digestion is 50°C-55°C, and the sludge stays in the anaerobic fermentation reactor for 6-10 days to complete the anaerobic digestion process. oxygen digestion process.

Further, the methane gas produced in the high-temperature anaerobic digestion process is collected and burned to generate steam or hot water to supply heat to the anaerobic fermentation reactor to maintain a high temperature of 50°C to 55°C, and the steam or hot water generated by methane combustion is passed through the anaerobic fermentation reactor. The circulating water pipeline at the bottom of the oxygen fermentation reactor supplies heat to the reaction tank, and at the same time, the agitator of the reaction tank is turned on.

The organic sludge in step ② is a liquid organic solid waste with a solid content of 4% to 7% and a volatile organic solid concentration of 60% to 90%.

The present invention has positive effects: (1) The organic sludge self-heating type high-temperature micro-aerobic-anaerobic digestion device of the present invention is composed of a self-heating type high-temperature micro-aerobic reactor and an anaerobic fermentation reactor connected in series. The self-heating high-temperature micro-aerobic reactor in the front section uses heat preservation measures to keep the heat released during the aerobic digestion of volatile organic compounds, plus mechanical heat generation, so that the reactor can reach a self-heating temperature of 45 ° C ~ 65 ° C, ensuring High-temperature micro-aerobic digestion proceeds smoothly.

Mesophilic digestion or high-temperature digestion can be selected in the anaerobic fermentation reactor in the latter stage. The mesophilic anaerobic digestion utilizes the heat of the sludge flowing out of the self-heating high-temperature micro-aerobic reactor, and no external heating source is needed, saving costs ; while part of the heat source for high-temperature anaerobic digestion comes from the self-heating type high-temperature micro-aerobic flow out of the sludge from the previous stage, and the other part of the heat source is obtained by burning methane produced by high-temperature anaerobic digestion, and no external heat source is also required. cut costs. The anaerobic fermentation reactor can produce methane gas with energy substances for resource utilization; and the digested sludge retains nitrogen and phosphorus nutrients, which can be used for agriculture after dehydration, solving the final outlet of sludge.

(2) The self-heating high-temperature micro-aerobic digestion process of the present invention ensures that the solid content of the incoming mud is 4% to 7%, the reactor volume is greater than 10m ³ , and an appropriate aeration rate is set and a good mixing effect is provided At the same time, the heat released by the aerobic digestion reaction is retained during the digestion process, and no more than 30% of the mechanical energy is supplied through the sludge reflux, so that the reactor reaches and maintains a high temperature state of 45 ° C ~ 65 ° C, making high temperature micro-aerobic Digestion is completed more effectively and thoroughly. Because it is a micro-aerobic digestion process, the amount of aeration is less than that of aerobic digestion, and it is difficult for the sludge in the reactor to rise above 70 degrees; while for the high-temperature micro-aerobic-anaerobic digestion process of organic sludge, some studies have shown that , when the digestion temperature of the self-heating high-temperature micro-aerobic digestion process exceeds 65 ° C, the effect of the entire digestion process becomes poor, specifically manifested in the low VSS removal rate of 20% to 30%.

(3) The first half of the organic sludge digestion process of the present invention is a self-heating high-temperature micro-aerobic digestion process rather than a self-heating high-temperature aerobic digestion process; the amount of air supplied by the self-heating high-temperature micro-aerobic digestion process is limited , under oxygen-limited conditions, it is easy to produce volatile fatty acids (hereinafter referred to as VFA), and VFA is easy to produce methane under anaerobic conditions; this is conducive to the further digestion of sludge in the second half of the anaerobic digestion process to produce methane , and can reduce aeration, reduce energy consumption. Due to the self-heating high-temperature micro-aerobic digestion process in the first half, the anaerobic digestion process is accelerated. Generally, anaerobic digestion takes more than 40 days or longer, but the residence time of this process can be shortened to less than 20 days.

(4) The present invention is suitable for liquid organic solid wastes with a solid content of 4% to 7% and a volatile organic solid concentration of 60% to 90%, such as urban sludge, organic waste discharged from poultry breeding plants, kitchen waste, etc. Liquid organic matter such as surplus and livestock manure. Due to the high concentration, high viscosity and high oxygen demand of the sludge put into the reactor, and the limited amount of oxygen entering the reactor through mass transfer, it is not completely aerobic in the autothermal high-temperature micro-aerobic reactor, that is, through The joint action of aerobic bacteria, facultative bacteria, and anaerobic bacteria degrades volatile organic compounds, and then enters anaerobic reactors to ferment and produce methane. After digestion, the sludge is dehydrated and can be used as organic solids for fertilizers, which solves the final problem of organic sludge. way out.

(5) The sludge after the self-heating high-temperature micro-aerobic digestion of the present invention adjusts the pH value and releases dissolved oxygen in the pH value adjustment tank. Since the self-heating high-temperature micro-aerobic digestion can produce a large amount of VFA, it is used for anaerobic digestion Methane is produced in the process, but VFA will cause the pH value to drop. Therefore, before entering the anaerobic tank, lye should be added to adjust the pH value in the anaerobic digester to between 6.8 and 7.2, not exceeding 7.5. In addition, the mixing tank has to stay for a period of time because the sludge flowing out of the self-heating high-temperature micro-aerobic digester contains some dissolved oxygen, which needs to be released and cannot be brought into the anaerobic tank, otherwise it will kill anaerobic bacteria . The pH value adjustment tank also acts as a deployment tank, which is convenient for the pump to take out the sludge from the pH value adjustment tank and pump it into the anaerobic fermentation reactor.

(6) The digestion device of the present invention is compact in structure and easy to operate. It can be built on the ground, buried or semi-buried, saving land and beautifying the environment.

Description of drawings

Fig. 1 is the structural representation of digestion device of the present invention;

The markings in the above drawings are as follows:

High-temperature micro-aerobic reactor 1, reaction tank 11, feed port 11-1, discharge port 11-2, vent port 11-3, sludge return system 12, aeration system 13, temperature sensor 14, gas absorption treatment device 15;

Anaerobic fermentation reactor 2, reaction tank 21, feed port 21-1, discharge port 21-2, vent port 21-3, agitator 22, gas collection filter 23, temperature sensor 24, gas sampling pipe 25, Circulating water pipeline 26; pH value adjustment pool 3.

Detailed ways

(Example 1)

As shown in FIG. 1 , the high-temperature micro-aerobic-anaerobic digestion device for organic sludge in this embodiment includes an autothermal high-temperature micro-aerobic reactor 1 , an anaerobic fermentation reactor 2 and a pH adjustment tank 3 . The pH adjustment tank 3 is arranged between the high-temperature micro-aerobic reactor 1 and the anaerobic fermentation reactor 2, and the outlet of the self-heating high-temperature micro-aerobic reactor 1 communicates with the pH adjustment tank 3 through a pipeline, and the pH value The adjustment tank 3 communicates with the feed port of the anaerobic fermentation reactor 2 through a pipeline and a pump.

The self-heating high-temperature micro-aerobic reactor 1 includes a reaction tank 11 , a sludge return system 12 , an aeration system 13 , a temperature sensor 14 and a gas absorption treatment device 15 .

The outer periphery of the reaction tank 11 is provided with an insulating layer, and the reaction tank 11 is provided with a feed port 11-1, a discharge port 11-2 and a vent port 11-3. The feed port 11 - 1 is arranged at the upper end of the reaction tank 11 , and the material outlet 11 - 2 and the vent port 11 - 3 are arranged at the bottom of the reaction tank 11 . The inside of the reaction tank 11 is provided with a feed zone, a reaction zone and a discharge zone, the feed zone is in the upper part, the reaction zone is in the middle, and the discharge zone is in the lower part.

The sludge return system 12 is outside the reaction tank 11 and includes a lower pipeline, a sludge return pump and an upper pipeline, and a check valve is arranged on the lower pipeline. The lower pipeline of the sludge return system 12 communicates with the bottom of the reaction tank 11 , and the discharge end of the upper pipeline communicates with the top of the reaction tank 11 . The sludge return pump is arranged between the lower pipeline and the upper pipeline, and the sludge is drawn out from the bottom of the reaction tank 11, and then re-enters the inside of the reaction tank 11 from the top of the reaction tank 11.

The aeration system 13 includes an aeration pipe, an aeration head, and a pressure gauge; the aeration pipe is arranged at the bottom of the reaction tank 11; the aeration head is evenly distributed on the aeration pipe and communicated with the aeration pipe. The aeration head can provide tiny bubbles to increase the contact area and contact time of the gas-liquid phase. The number of aeration heads is related to its service area; the pressure gauge can monitor whether the aeration head is blocked, so as to unblock it in time. In the early stage of the reaction, the organic sludge needs more oxygen and the aeration rate needs to be increased; in the later stage of the reaction, the organic sludge needs less oxygen and the aeration rate needs less. A flow meter can also be added to the aeration system of the reactor to adjust the flow of the aeration pipe.

One temperature sensor 14 is respectively arranged on the upper part, the middle part and the lower part of the reaction tank 11 to detect the temperature of the sludge in the reaction tank 11 .

The gas absorption treatment device 15 is arranged above the reaction tank 11 and communicates with the inside of the reaction tank 11 through a pipe. The gas absorption treatment device 15 is a biofilm absorption and filtration device, which can process acid gases such as H ₂ S and SO ₂ .

The anaerobic fermentation reactor 2 includes a reaction tank 21 , an agitator 22 , a gas collection filter 23 , a temperature sensor 24 , a gas sampling pipe 25 and a circulating water pipeline 26 .

Reactor 21 is provided with feed inlet 21-1, feed outlet 21-2 and vent 21-3, and feed inlet is arranged on the top of reactor 21, and feed outlet 21-2 is arranged on the middle part of reactor 21, The vent 21 - 3 is provided at the bottom of the reaction tank 21 .

There are three areas in the reaction tank 21, which are successively divided into a feed area, a reaction area and a discharge area. The feed area is located at the top, the reaction area is located at the bottom, and the discharge area is located at the middle.

The agitator 22 includes a motor, a rod shaft and stirring blades, the motor is fixedly arranged above the reaction tank 21, the rod shaft penetrates into the inside of the reaction tank 21 from top to bottom, and the stirring blades are arranged in two layers on the rod shaft, wherein the lower layer The stirring blades are 30cm away from the bottom of the reaction tank 21, and the upper stirring blades are set in the middle of the effective water depth in the reaction tank 21, and the motor drives the two layers of blades to rotate to fully mix and stir the sludge in the tank. The stirrer 22 is not turned on all the time for 24 hours, but is turned on when the reaction tank 21 is supplied with heat, and the stirring is stopped after the heat supply is finished.

The gas collection filter 23 is arranged above the reaction tank 21 and communicates with the inside of the reaction tank 21 through a pipe. The gas collection filter 23 collects the methane gas generated in the reaction tank 21 , and stores or burns the methane gas generated in the reaction tank 21 to provide heat for the reaction tank 21 .

One temperature sensor 24 is respectively arranged on the upper part, the middle part and the lower part of the reaction tank 21 to detect the temperature of the sludge in each area in the reaction tank 11 .

One gas sampling tube 25 is respectively provided at the upper part, the middle part and the lower part of the reaction tank 21 to detect the gas components in each area in the reaction tank 11 .

The circulating water pipeline 26 is arranged at the bottom of the reaction tank 21 and is connected to the boiler through the pipeline, and the gas stove of the boiler is communicated with the gas outlet of the gas collection filter 23 through the pipeline.

The high-temperature micro-aerobic-anaerobic digestion method for organic sludge using the above-mentioned digestion device comprises the following steps:

① Domestication of strains.

Take municipal sludge with a solid content rate of 5% to 7% and put it into the high-temperature micro-aerobic reactor 1, open the sludge return system 12 and the aeration system 13, and perform aerobic digestion for a period of time until the temperature rises and reaches equilibrium After that (that is, the temperature of the sludge in the reaction tank 11 does not rise any more), discharge 1/2 of the sludge in the reaction tank 11, and then replenish fresh sludge with a solid content rate of 5% to 7%, continue to operate, repeat the above steps until the reaction The temperature in the tank 11 reaches 50°C to 55°C. When the temperature rises above 50°C, stop the aeration and sludge reflux, and discharge a part of the sludge after acclimatization is completed, and reserve 1/3 of the sludge in the reaction tank 11 as seed sludge.

②High-temperature micro-aerobic digestion process of organic sludge.

Turn on the sludge delivery pump, and send into the reaction tank 11 of the self-heating type high-temperature micro-aerobic reactor 1 the organic sludge of 2/3 effective volume of the reaction tank 11, and the organic sludge and the reserved domesticated sludge are loaded The reactor is full to reach the effective volume, and the reactor has a super height of 0.5m; the solid content of organic sludge is 4% to 7%, and the concentration of volatile organic solids accounts for 60% to 80%; open the sludge return system 12 and aeration System 13, the aeration rate of the aeration system 13 is 10-14m ³ /h, and the organic sludge starts the high-temperature micro-aerobic digestion process. The sludge stays in the self-heating high-temperature micro-aerobic reactor for 2 to 3 days to carry out the high-temperature micro-aerobic digestion process. During the high-temperature micro-aerobic digestion process, the oxidation-reduction potential ORP is 0~-100mv.

During the digestion process, the sludge aerobic digestion process is self-exothermic, and the sludge reflux supplies no more than 30% of the mechanical energy. At the same time, since the outer periphery of the reactor body of the self-heating high-temperature micro-aerobic reactor 1 is provided with an insulation layer, the The digestion temperature does not require an external heat source, and is maintained between 45°C and 65°C. At this high temperature, the organic sludge is sterilized and the digested sludge is harmless. If the temperature of the reactor rises above 65°C, increase the aeration rate and close the sludge return to increase the heat dissipation to achieve cooling.

Due to the high concentration, high viscosity and high oxygen demand of the sludge put into the reactor, and the limited amount of oxygen entering the reactor through mass transfer, it is not completely aerobic in the autothermal high-temperature micro-aerobic reactor, that is, through The joint action of aerobic bacteria, facultative bacteria and anaerobic bacteria degrades volatile organic compounds and easily produces volatile fatty acids (VFA). Under anaerobic conditions, VFA can easily produce methane, so the high temperature and micro The aerobic digestion process is beneficial to the anaerobic digestion process of the organic sludge in the later stage.

After the high-temperature micro-aerobic digestion is completed, the digested sludge enters the pH value adjustment tank 3 from the discharge port through the pipeline, and puts sodium hydroxide solution into the pH value adjustment tank 3 to adjust the pH value of the material in the pH value adjustment tank 3. The value is adjusted to between 6.8 and 7.2. After the pH value is adjusted, the sludge stays in the tank for 3h to 5h to release the dissolved oxygen in the sludge.

③Mesophilic anaerobic digestion of organic sludge.

Turn on the sludge pump, and the sludge that has been digested by high-temperature micro-aerobic digestion to release dissolved oxygen in step ② is pumped into the anaerobic fermentation reactor 2 . The sludge stays in the anaerobic fermentation reactor 2 for 10 to 20 days to complete the anaerobic digestion process without external heating source, the temperature of mesophilic anaerobic is 33°C to 35°C, and the discharged sludge is directly used in agriculture after mechanical dehydration.

If the temperature of the sludge flowing out after self-heating high-temperature micro-aerobic digestion is too high, exceeding 60° C., the sludge after high-temperature micro-aerobic digestion should be kept in the pH adjustment tank 3 for several hours to dissipate heat. If the temperature of the anaerobic tank does not reach the medium temperature range, the sludge temperature of the self-heating high-temperature micro-aerobic digestion can be increased as much as possible. Reach 50°C to 60°C to ensure the medium temperature of the anaerobic tank.

The digestion device of the present invention belongs to two-stage series reactors, and the self-heating high-temperature micro-aerobic reactor is stirred and mixed through the sludge reflux, and the mixing has no dead angle, so as to achieve the sludge suspension effect, promote the biochemical reaction of microorganisms, and completely complete the oxidation reaction of microorganisms , in the self-heating high-temperature micro-aerobic reactor, enough heat is released through micro-aerobic digestion to ensure the high-temperature state of the micro-aerobic reactor and the medium-temperature state of the sludge in the anaerobic fermentation reactor.

In actual operation, a semi-continuous feeding and discharging method is adopted. In this example, the residence time of autothermal high-temperature micro-aerobic digestion sludge is 2 days, and the residence time of anaerobic digestion sludge is 12 days.

Assuming that the effective volume of the self-heating high-temperature micro-aerobic digestion reactor is V, the amount of mud entering on the first day is V/2, and it stays for two days. That is to say, the mud is fed and the mud is discharged every other day. From the self-heating high-temperature micro-aerobic digestion reactor, the sludge V is discharged every day and enters the anaerobic digestion tank. The volume of the anaerobic digestion tank is 12V, so the sludge residence time is 12 days. The daily sludge discharge volume of the anaerobic digester is V. In this way, mud entry and mud discharge are equal.

For the autothermal high-temperature micro-aerobic digestion, since it is an autothermal type, the temperature rise is not easy, so the volume of the reactor in this embodiment is 10m ³ . The temperature in the self-heating high-temperature micro-aerobic digestion stage of this embodiment can reach between 45°C and 65°C. Although it will be lower in winter, it can be maintained at a minimum of 50°C due to the large volume of the reactor.

The high-temperature micro-aerobic-anaerobic digestion method for organic sludge of the present invention utilizes the advantage of self-heating high-temperature micro-aerobic digestion that can generate heat by itself, does not require an external heating source, and saves costs.

The anaerobic fermentation of the digestion device of the present invention is mesophilic digestion, which utilizes the heat of the sludge in the self-heating high-temperature micro-aerobic medium, does not require an external heating source, and saves costs. The anaerobic fermentation reactor can produce methane gas with energy substances for resource utilization; and the digested sludge retains nitrogen and phosphorus nutrients, which can be used for agriculture after dehydration, solving the final outlet of sludge.

(Example 2)

The organic sludge high-temperature micro-aerobic-anaerobic digestion method of the present embodiment is identical with embodiment 1 except that:

Step ③ The organic sludge is subjected to high-temperature anaerobic digestion.

Open the valve connected to the pipeline, step ② releases the dissolved oxygen and is pumped into the anaerobic fermentation reactor 2 through the high-temperature micro-aerobic digestion sludge. The sludge stays in the anaerobic fermentation reactor 2 for 6-10 days to complete the anaerobic digestion process. The temperature of the high-temperature anaerobic digestion is 50°C-55°C, and the discharged sludge is directly used for agriculture after mechanical dehydration.

High-temperature anaerobic digestion can speed up the reaction rate. Part of the heat source for high-temperature anaerobic digestion comes from the self-heating type high-temperature micro-aerobic flow out of the sludge in the previous stage. The other part of the heat source is the steam or hot water obtained by collecting methane generated by high-temperature anaerobic digestion and burning water. Heat is supplied to the sludge in the reaction tank 21 through the circulating water pipeline 26 in the anaerobic fermentation reactor 2 to maintain a high temperature of 50°C to 55°C.

When the temperature of the anaerobic fermentation reactor 2 drops, steam or hot water is sent to the circulating water pipeline 26 to provide heat to the sludge in the reaction tank 21, and the agitator 22 is turned on to disperse the heat while the circulating water pipeline 26 is heating. Evenly, stop stirring at the end of heating.

(Example 3)

The organic sludge high-temperature micro-aerobic-anaerobic digestion method of the present embodiment is identical with embodiment 1 except that:

The self-heating type high-temperature micro-aerobic reactor 1 also includes a defoaming system, and the defoaming system includes an air defoaming pipe and an injection port; A small hole; the injection port is installed on the top of the reactor body. When the defoaming system is working, the gas blown out through the small holes on the wall of the air defoaming pipe breaks the foam; the injection port can spray the defoamer, and the defoamer is sprayed into the reactor and evenly distributed by the agitator It acts as a defoamer on the entire liquid surface.

Steps of the digestion method ② During the high-temperature micro-aerobic digestion process of organic sludge, the defoaming system sends air into the reaction tank to break the bubbles generated in the reaction tank, so that the digestion process goes smoothly.

Claims (9)

1. A high-temperature micro-aerobic-anaerobic digestion device for organic sludge, comprising a high-temperature aerobic reactor and anaerobic fermentation reactor (2), characterized in that: it also includes a pH value adjustment tank (3); the high-temperature The aerobic reactor is a self-heating high-temperature micro-aerobic reactor (1); the pH adjustment tank (3) is set between the high-temperature micro-aerobic reactor (1) and the anaerobic fermentation reactor (2), and the self-heating The discharge port of the high-temperature micro-aerobic reactor (1) communicates with the pH value adjustment tank (3) through the pipeline, and the pH value adjustment tank (3) communicates with the feed port of the anaerobic fermentation reactor (2) through the pipeline and the pump Connected; The self-heating high-temperature micro-aerobic reactor (1) includes a reaction tank (11), a sludge return system (12), an aeration system (13), a temperature sensor (14) and a gas absorption treatment device (15); The sludge return system (12) is set outside the reaction tank (11), including the lower pipeline, the sludge return pump and the upper pipeline; the lower pipeline, the sludge return pump, the upper pipeline and the reaction tank form a connected loop The aeration system (13) includes an aeration pipe, an aeration head, and a pressure gauge, and the aeration pipe is arranged at the bottom of the reaction tank (11); the temperature sensor (14) is located at the upper, middle, and lower parts of the reaction tank (11) Each is provided with one; the gas absorption treatment device (15) is arranged above the reaction tank (11), and communicates with the inside of the reaction tank (11) through a pipe. 2. The organic sludge high-temperature micro-aerobic-anaerobic digestion device according to claim 1, characterized in that: the anaerobic fermentation reactor (2) includes a reaction tank (21), an agitator (22), a gas collection filter device (23), temperature sensor (24), gas sampling tube (25) and circulating water pipeline (26); The stirrer (22) includes a motor, a rod shaft and stirring blades, the motor is fixedly arranged above the reaction tank (21), the rod shaft penetrates into the inside of the reaction tank (21) from top to bottom, and the stirring blades are set on the rod shaft Two layers, wherein the stirring blades of the lower layer are set at the bottom of the reaction tank (21), and the stirring blades of the upper layer are set at the middle of the effective water depth in the reaction tank (21); The circulating water pipeline (26) is arranged at the bottom of the reaction tank (21), and is connected to the boiler through the pipeline, and the gas stove of the boiler is connected to the gas outlet of the gas collection filter (23) through the pipeline. 3. a digestion method of organic sludge high-temperature micro-aerobic-anaerobic digestion device as claimed in claim 1, is characterized in that comprising the following steps: ① The domestication of the strains, the domestication of the strains is carried out in the reaction tank (11) of the self-heating high-temperature micro-aerobic reactor (1), and 1/4 to 1/2 of the seed sludge containing the strains obtained from the domestication is left in the Inside the reaction tank (11); ②The high-temperature micro-aerobic digestion process of organic sludge; turn on the sludge delivery pump, and send organic sludge into the reaction tank (11) of the self-heating high-temperature micro-aerobic reactor (1), and the transport volume of organic sludge is the remaining effective volume of the reaction tank (11); the sludge return system (12) and the aeration system (13) are turned on, and the organic sludge starts the high-temperature micro-aerobic digestion process, and the sludge is in the self-heating high-temperature micro-aerobic reactor Stay in the middle for 2 to 3 days to complete the high-temperature micro-aerobic digestion process; the digestion temperature is maintained between 45°C and 65°C; After the high-temperature micro-aerobic digestion, the digested sludge enters the pH adjustment tank (3) from the discharge port through the pipeline, puts lye into the pH adjustment tank (3), and puts the pH value adjustment tank (3) The pH value of the raw material is adjusted to between 6.8 and 7.2, and the sludge after the pH value adjustment is completed stays in the tank for 3 to 5 hours to release the dissolved oxygen in the sludge; ③ Anaerobic digestion process of organic sludge; Step ② The sludge that releases dissolved oxygen and undergoes high-temperature micro-aerobic digestion is pumped into the anaerobic fermentation reactor (2) stays for 6 to 20 days to complete the anaerobic digestion process, and the sludge is discharged After mechanical dehydration, it can be directly used in agriculture. 4. The high-temperature micro-aerobic-anaerobic digestion method for organic sludge according to claim 3, characterized in that: step ② in the high-temperature micro-aerobic digestion process of organic sludge, the self-heating high-temperature micro-aerobic reactor ( 1) The oxidation-reduction potential ORP in the reaction tank (11) is 0-100mv. 5. The high-temperature micro-aerobic-anaerobic digestion method for organic sludge according to claim 3, characterized in that: step ③ the anaerobic digestion process of organic sludge is a mesophilic anaerobic digestion process; the mesophilic anaerobic temperature is 33°C ~35°C, the sludge stays in the anaerobic fermentation reactor (2) for 10-20 days to complete the anaerobic digestion process. 6. The high-temperature micro-aerobic-anaerobic digestion method for organic sludge according to claim 5, characterized in that: if the temperature of the sludge flowing out after autothermal high-temperature micro-aerobic digestion exceeds 60°C, the high-temperature micro-aerobic The residence time of the digested sludge in the pH adjustment tank (3) is extended by 0 to 40 minutes to dissipate heat to the mesophilic anaerobic temperature range; The amount of aeration and increasing the sludge return to give mechanical heat make the high-temperature micro-aerobic digestion temperature reach 50 ℃ ~ 60 ℃, and ensure the medium temperature of the anaerobic tank. 7. the organic sludge high-temperature micro-aerobic-anaerobic digestion method according to claim 3 is characterized in that: step 3. the anaerobic digestion process of organic sludge is a high-temperature anaerobic digestion process; the temperature of the high-temperature anaerobic digestion is 50°C-55°C, the sludge stays in the anaerobic fermentation reactor (2) for 6-10 days to complete the anaerobic digestion process. 8. The high-temperature micro-aerobic-anaerobic digestion method for organic sludge according to claim 7, characterized in that: the methane gas produced by the high-temperature anaerobic digestion process is collected and post-combusted to generate steam or hot water for the anaerobic fermentation reactor (2) Heat supply to maintain a high temperature of 50°C to 55°C, supply heat to the reaction tank (21) through the circulating water pipeline (26) at the bottom of the anaerobic fermentation reactor (2) through the steam or hot water generated by methane combustion, Open the agitator of reaction tank (21) simultaneously. 9. The high-temperature micro-aerobic-anaerobic digestion method for organic sludge according to claim 3, characterized in that: the organic sludge in step 2 has a solid content of 4% to 7%, and the concentration of volatile organic solids accounts for 60% to 90% of liquid organic solid waste.

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