CN102583927B - Sludge micro oxygen hydrolytic acidizing method - Google Patents

Abstract

The invention relates to a sludge treatment method by microaerobic hydrolysis and acidification. The sludge containing acid-producing bacteria is inoculated in the hydrolysis and acidification reactor, air is intermittently introduced into the hydrolysis and acidification reactor for air stirring, and at the same time, the intermittent mechanical Stirring, hydrolyzing and acidifying the sludge of the sewage treatment plant under the micro-aerobic condition of maintaining dissolved oxygen DO of 0.4-0.8mg/L, the sludge after hydrolytic acidizing treatment enters the sedimentation tank for mud-water separation, and the supernatant is used as urban sewage biological decontamination Carbon source for nitrogen and phosphorus removal treatment. The microaerobic hydrolysis and acidification treatment sludge method of the present invention is carried out at normal temperature, does not need to add acid and alkali to adjust the pH value, is simple to operate, runs stably, can inhibit the growth of methane bacteria, and improves the stability of the sludge hydrolysis and acidification treatment system. The amount of acid produced by mud is increased by 38% to 50%, and at the same time, the sludge is reduced and stabilized to the greatest extent.

Description

Micro-aerobic hydrolysis and acidification treatment of sludge

technical field

The invention belongs to the technical field of sludge treatment and resource utilization, and relates to a treatment method for sewage treatment plant sludge, in particular to a microaerobic hydrolysis acidification treatment method for sewage treatment plant sludge.

Background technique

Sludge from sewage treatment plants is hydrolyzed and fermented under anaerobic conditions to produce short-chain volatile acids such as acetic acid, propionic acid, and butyric acid. Using the acidic fermentation product of sludge as the carbon source of denitrifying bacteria and phosphorus accumulating bacteria can reduce the cost of sewage treatment, and can reduce and recycle sludge in sewage plants.

Since the 1980s, there have been more and more studies abroad on the hydrolysis and acidification stage of anaerobic digestion, most of which use the primary sedimentation tank sludge hydrolysis fermentation of sewage treatment plants to produce volatile fatty acids (VFA), and some use primary sedimentation The mixed sludge of sludge and excess sludge was studied. However, domestic research on acid production from sludge is rare. Some existing studies have shown that the optimum pH of acidogenic bacteria is 6.0-7.0, and this range conflicts with the optimum pH of 6.5-7.5 for methanogens, so methanation will inevitably occur in the sludge hydrolysis acidification reactor Phenomenon, make the system run unstable, and the acid production of sludge is low.

ZL 200810054486.1 provides a method for preparing carbon sources for wastewater treatment. In this patent, the pH value of the biochemical reaction in the acid fermentation reactor during the acid fermentation stage is 5.5 to 6.5, and the temperature of the acid fermentation reactor is controlled at 26°C to 38°C. ℃. This patent requires a heating device to control the temperature, adding acid to control the pH, the production cost is high, and the amount of acid produced by the sludge is low.

Hu Yinghua et al. [Energy and Environmental Protection, 2005, 19(1): 28-31] carried out a pilot study on microaerobic digestion of excess sludge in sewage plants. In their reactor, part of the sludge was in an aerobic state, and part of the sludge In the anoxic state, in the aerobic state, facultative bacteria use oxygen as the electron acceptor to degrade organic matter, and in the anoxic condition, part of the nitrate replaces oxygen as the electron donor, and the degradation is achieved through endogenous nitrate respiration. purpose of microorganisms. The digestion time in this study was 20 days, but no accumulation of high concentrations of volatile acids was seen.

[Shanghai Environmental Science, 1995, 14(11): 15-16] carried out research on the micro-aerobic digestion process of excess sludge. The sludge reduction effect is good, but because only air stirring is used, the sludge is easy to digest. It was deposited at the bottom, and there was no accumulation of high-concentration volatile acids.

Contents of the invention

The purpose of the present invention is to provide a method for sludge treatment by microaerobic hydrolysis and acidification, which can improve the stability of the sludge hydrolysis and acidification treatment system and significantly increase the amount of acid produced by sludge.

The microaerobic hydrolysis and acidification treatment sludge method of the present invention is to inoculate the sludge containing acid-producing bacteria in the hydrolysis and acidification reactor, intermittently feed air into the hydrolysis and acidification reactor for air stirring, and at the same time assist intermittent mechanical stirring. Under the micro-aerobic condition with dissolved oxygen DO of 0.4-0.8 mg/L, the sludge of the sewage treatment plant is hydrolyzed and acidified, and the sludge after hydrolytic acidification is sent to the sedimentation tank for separation of mud and water, and the supernatant is used as urban sewage biological nitrogen and phosphorus removal Treated carbon sources.

In the present invention, air stirring and mechanical stirring are carried out at the same time, stirring once every 40-60 minutes, and each stirring time is 5-10 minutes.

Among them, the mechanical stirring intensity is preferably 10-15 W/m ³ ; the air volume of the air stirring is preferably 0.06-0.14 m ³ /m ³ cell volume·min.

The microaerobic hydrolysis acidification method of the present invention carries out hydrolysis acidification under the condition of 20 DEG C to 25 DEG C, during which the pH value in the hydrolysis acidification reactor is maintained at 6.0 to 7.0.

The preferred hydrolytic acidification reactor of the present invention is a sequencing batch reactor.

The microaerobic hydrolysis acidification treatment sludge method of the present invention specifically comprises the following process steps:

1. Cultivation and domestication of acid-producing bacteria

Inoculate the aerobic sludge from the sewage treatment plant accounting for 50% to 70% of the reactor volume in the hydrolytic acidification reactor, and add carbohydrate organic waste water as the medium, and carry out mechanical stirring and air stirring, both at the same time, every interval Stir once every 40 to 60 minutes, each stirring time is 5 to 10 minutes, the mechanical stirring intensity is 10 to 15 W/m ³ , and the air volume of air stirring is 0.06 to 0.14 ^{m 3} /m ³ pool capacity min to maintain the dissolved oxygen in the hydrolysis acidification reactor. DO is 0.4～0.8mg/L under micro-aerobic conditions; during the cultivation and acclimatization process, no sludge is discharged, only the supernatant is discharged intermittently, after the supernatant is discharged, an equal volume of carbohydrate-based organic wastewater is added as the medium, and the discharge Stop stirring before the supernatant, settle for 0.5-1h, and cycle operation; the COD concentration and volume of carbohydrate organic wastewater added every day are determined by the organic loading rate and hydraulic retention time, the organic loading rate is 3 ~ 4gCOD/L·d, and the hydraulic retention The time is 3 to 4 days; when the concentration of volatile acid in the hydrolytic acidification reactor reaches above 3000 mg/L, the cultivation and acclimation of acid-producing bacteria is completed;

2. Hydrolysis and acidification of sewage treatment plant sludge

Sludge from sewage treatment plants with a VS (volatile solid concentration) of 15-25g/L and a ratio of VS/TS (volatile solid concentration/total solid concentration) greater than 0.5 is used as input sludge, which has been cultivated and domesticated in step 1. In the acid bacteria reactor, mechanical stirring and air stirring are carried out at the same time, stirring once every 40-60 minutes, each stirring time is 5-10 minutes, the mechanical stirring intensity is 10-15W/m ³ , and the air stirring air volume is 0.06 ～0.14m ³ /m ³ pool volume·min; the sludge entering the reactor is discharged after the solid residence time of 3～6d is met, and the sludge should be stirred for 5～10min every day before sludge discharge, and the mud-water mixture rich in volatile acids is discharged, and at the same time Add the same volume of sludge from the new sewage treatment plant, and recycle the operation;

The above-mentioned reactor is hydrolyzed and acidified at 20°C-25°C. After the reactor is started, the pH value in the reactor is naturally maintained at 6.0-7.0 by the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced by it. Add acid-base adjustment;

3. Sludge-water separation of sludge after hydrolysis and acidification

The volatile acid-rich mud-water mixture discharged from step 2 enters the sedimentation tank for mud-water separation, and the supernatant of the sedimentation tank is recycled as a carbon source for the urban sewage biological denitrification and phosphorus removal process, and the settled waste sludge is directly discharged.

Among them, the hydraulic retention time for the mud-water mixture to enter the sedimentation tank for mud-water separation is 1 to 2 hours.

The invention provides a method for sludge treatment by microaerobic hydrolysis and acidification, which can inhibit the growth of methane bacteria and improve the stability of the sludge hydrolysis and acidification treatment system and the amount of acid produced by the sludge. At the same time, the sludge can be reduced and stabilized to the greatest extent. The advantages of this method are mainly reflected in the following aspects:

1. The microaerobic hydrolysis acidification method is easy to operate for sludge treatment in sewage treatment plants. Air stirring and mechanical stirring are used in the reactor. The two stirring methods are carried out at the same time, stirring once every 40 to 60 minutes. This stirring method improves the sludge The sedimentation ratio prolongs the time of sludge mixing reaction, more importantly, it inhibits the growth of methane bacteria, increases the production of volatile acids in sludge, and increases the stability of system operation.

2. The microaerobic hydrolysis acidification method can be operated at normal temperature, without heating and airtightness, and without adding acid and alkali to adjust the pH value of the reactor, and the operating conditions are simplified. the

3. Sewage treatment plant sludge belongs to the solid waste of sewage treatment plants. The microaerobic hydrolysis acidification method is simple to treat sewage treatment plant sludge. The fermentation products of acetic acid, propionic acid and butyric acid can be used as sewage biological denitrification and phosphorus removal process. The carbon source of nitrifying bacteria and phosphorus accumulating bacteria reduces the cost of sewage treatment and realizes the resource utilization of sludge at the same time.

4. Using the microaerobic hydrolysis acidification method to treat high-concentration suspended solid sludge can not only obtain the ideal volatile acid production, but also achieve a good VS removal effect. The acid production of sludge is 0.11-0.19gVFA/gVS, and the VS removal rate 35% to 44%, the system runs stably, and the effect of sludge reduction and stabilization is good.

5. Compared with the sludge acid fermentation method using a semi-continuous operation reactor, the method of the present invention is stable in operation, and the acid production can be increased by 38% to 50%. The specific comparison data are shown in Table 1.

Detailed ways

Example 1

The hydrolytic acidification reactor adopts a sequencing batch reactor, and the return sludge from the aeration tank of the sewage treatment plant is inoculated into the sequencing batch reactor, and the amount of inoculated sludge is 60% of the reactor volume. After inoculation, add carbohydrate organic waste water as the medium, carry out mechanical stirring and air stirring in the sequencing batch reactor at room temperature, both at the same time, stirring once every 60 minutes, each stirring time is 5 minutes, and the mechanical stirring intensity is 10W /m ³ , the amount of air stirred by air is 0.06m ³ /m ³ cell volume·min, so as to maintain the micro-aerobic condition where the DO in the reactor is 0.4mg/L. The cultivation and acclimatization of acid-producing bacteria generally takes 7 to 14 days. No sludge is discharged during the cultivation process. The supernatant is discharged after the stirring is stopped and allowed to settle for 1 hour every day, and at the same time, an equal volume of carbohydrate organic wastewater is added, and the above cycle operate. The COD concentration and volume of carbohydrate organic wastewater added every day are determined by the organic loading rate and hydraulic retention time. The organic loading rate is 3gCOD/L·d, and the hydraulic retention time is 3d. When the volatile acid concentration in the hydrolysis acidification reactor reaches above 3000mg/L, the cultivation and acclimation of acid-producing bacteria is completed.

After the acid-producing bacteria have been cultivated and domesticated, the sludge from the sewage treatment plant is used as the input sludge of the sequencing batch reactor containing the above-mentioned cultivated and domesticated acid-producing bacteria. A certain volume of sludge-water mixture of treated sludge is discharged instantaneously, and enters an equal volume of sewage treatment plant sludge from the upper part of the reactor. Pre-stir for 5 minutes before each mud discharge. The amount of sludge entering the reactor instantaneously every day is controlled by the solid residence time, which is expressed by SRT. The volume of the sequencing batch reactor is V, the unit is m ³ , and the amount of sludge added every day is V ₁ , the unit is m ³ . V=SRT×V ₁ . This example controls the VS 15g/L entering the sludge, VS/TS=0.51, and SRT 6d. The stirring method during the hydrolysis and acidification of the sludge is the same as that of the above-mentioned acid-producing bacteria cultivation and acclimation stage, the temperature is 20°C, and the reactor The pH value is naturally maintained at 6.5 by the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced, without additional adjustment and control.

The discharged mud-water mixture enters the sedimentation tank and settles for 1 hour. The supernatant of the sedimentation tank is recycled as the carbon source of the urban sewage biological nitrogen and phosphorus removal process, and the settled waste sludge is discharged.

Example 2

Stirring interval time 60min, stirring time 7min, SRT 4d, other are with embodiment 1.

Example 3

The stirring interval is 40 minutes, the stirring time is 5 minutes, the VS entering the sludge is 20g/L, VS/TS=0.55, and the SRT is 3 days. The pH value in the reactor depends on the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced by it. At 6.0, others are the same as in Example 1.

The volatile acid concentration in the mud-water mixture after hydrolysis and acidification treatment was 2693mg/L, the acid production of sludge was 0.14gVFA/gVS, and the removal rate of VS was 35%.

Example 4

Stirring interval 40min, stirring time 10min, the VS 20g/L that enters sludge, SRT 4d, other are with embodiment 3.

The volatile acid concentration in the mud-water mixture after hydrolysis and acidification treatment was 2965 mg/L, the acid production of the sludge was 0.15 gVFA/gVS, and the removal rate of VS was 39%.

Example 5

The stirring interval is 50 minutes, the stirring time is 10 minutes, the VS entering the sludge is 25g/L, the SRT is 3 days, the temperature is 23°C, and the pH value in the reactor is naturally maintained at 6.5 depending on the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced by it. , other with embodiment 3.

Example 6

The stirring interval is 40 minutes, the stirring time is 10 minutes, the VS entering the sludge is 25g/L, the SRT is 4 days, and the temperature is 25°C. The pH value in the reactor is naturally maintained at 7.0 by the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced by it. , other with embodiment 1.

Example 7

The hydrolytic acidification reactor adopts a sequencing batch reactor, and the aerobic sludge from the sewage treatment plant is inoculated into the sequencing batch reactor, and the amount of inoculated sludge is 70% of the reactor volume. After inoculation, add carbohydrate organic waste water as the culture medium, carry out mechanical stirring and air stirring in the sequencing batch reactor at room temperature, both at the same time, stirring once every 60 minutes, each stirring time is 7 minutes, and the mechanical stirring intensity is 12W /m ³ , the amount of air stirred by air is 0.11m ³ /m ³ cell volume·min, so as to maintain the micro-aerobic condition of dissolved oxygen DO in the reactor at 0.6mg/L. The cultivation and domestication of acid-producing bacteria generally takes 7 to 14 days. No sludge is discharged during the cultivation process. The supernatant is discharged after stopping stirring and standing for 0.5 hours every day. Loop operation. The COD concentration and volume of carbohydrate organic wastewater added every day are determined by the organic loading rate and hydraulic retention time. The organic loading rate is 3gCOD/L·d, and the hydraulic retention time is 4d. When the volatile acid concentration in the hydrolysis acidification reactor reaches above 3000mg/L, the cultivation and acclimation of acid-producing bacteria is completed.

After the acid-producing bacteria have been cultivated and domesticated, the sewage treatment plant sludge is used as the input sludge of the sequencing batch reactor containing the above-mentioned cultivated and domesticated acid-producing bacteria, and a semi-continuous operation mode is adopted to discharge a certain volume of treated sewage instantaneously every day. The mud-water mixture of mud enters an equal volume of sewage treatment plant sludge. Before each mud discharge, pre-stir for 8 minutes. Control the VS 15g/L entering the sludge, VS/TS=0.6, SRT 6d, the stirring method during the hydrolysis and acidification of the sludge is the same as the above-mentioned stirring method in the cultivation and acclimation stage of acid-producing bacteria, the temperature is 23°C, and the pH value in the reactor depends on The acid-producing bacteria in the reactor and the volatile acid and alkalinity they produce are naturally maintained at 6.5, without additional adjustment and control.

The discharged mud-water mixture enters the sedimentation tank and settles for 1.5 hours. The supernatant of the sedimentation tank is recycled as the carbon source of the urban sewage biological nitrogen and phosphorus removal process, and the settled waste sludge is discharged.

Example 8

Stirring time 5min, SRT 4d, other are with embodiment 7.

Example 9

The stirring interval is 50min, the SRT is 3 days, the temperature is 20°C, the pH value in the reactor is naturally maintained at 6.38 depending on the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced by it, and the others are the same as in Example 7.

The volatile acid concentration in the mud-water mixture after hydrolysis and acidification treatment was 2425mg/L, the acid production of the sludge was 0.16gVFA/gVS, and the removal rate of VS was 38%.

Example 10

Stirring interval time 60min, stirring time 10min, enter the VS 20g/L of sludge, SRT 4d, other are with embodiment 9.

Example 11

Stirring interval 40min, stirring time 5min, SRT 6d, the pH value in the reactor depends on the volatile acid and the alkalinity that acid-producing bacteria and its production in the reactor are naturally maintained at 6.42, and others are the same as in Example 10.

The volatile acid concentration in the mud-water mixture after hydrolysis and acidification treatment was 3665mg/L, the acid production of the sludge was 0.18gVFA/gVS, and the removal rate of VS was 36%.

Example 12

The stirring interval is 50min, the temperature is 25°C, and the VS of the sludge is 25g/L. The pH value in the reactor is naturally maintained at 6.46 depending on the acid-producing bacteria and the volatile acid and alkalinity produced in the reactor. Others are the same as in Example 7.

The volatile acid concentration in the mud-water mixture after hydrolytic acidification treatment was 4618mg/L, the acid production of sludge was 0.19gVFA/gVS, and the removal rate of VS was 36%.

Example 13

The VS 20g/L that enters sludge, SRT 4d, the pH value in the reactor depends on the volatile acid and the alkalinity that acid-producing bacteria and its production in the reactor are naturally maintained at 6.91, and others are the same as in Example 12.

The volatile acid concentration in the mud-water mixture after hydrolysis and acidification treatment was 3391 mg/L, the acid production of the sludge was 0.17 gVFA/gVS, and the VS removal rate was 38%.

Example 14

The hydrolytic acidification reactor adopts a sequencing batch reactor, and the aerobic sludge from the sewage treatment plant is placed in the sequencing batch reactor for inoculation, and the amount of inoculated sludge is 70% of the reactor volume. After inoculation, add carbohydrate organic waste water as the culture medium, carry out mechanical stirring and air stirring in the sequencing batch reactor at room temperature, both at the same time, stirring once every 60 minutes, each stirring time is 10 minutes, and the mechanical stirring intensity is 15W /m ³ , the amount of air stirred by air is 0.14m ³ /m ³ cell volume·min, so as to maintain the micro-aerobic condition of DO in the reactor at 0.8mg/L. The cultivation and acclimatization of acid-producing bacteria generally takes 7 to 14 days. No sludge is discharged during the cultivation process. The supernatant is discharged after the stirring is stopped and allowed to settle for 1 hour every day, and at the same time, an equal volume of carbohydrate organic wastewater is added, and the above cycle operate. The COD concentration and volume of carbohydrate organic wastewater added every day are determined by the organic loading rate and hydraulic retention time. The organic loading rate is 4gCOD/L·d, and the hydraulic retention time is 3d. When the volatile acid concentration in the hydrolysis acidification reactor reaches above 3000mg/L, the cultivation and acclimation of acid-producing bacteria is completed.

After the acid-producing bacteria have been cultivated and domesticated, the sewage treatment plant sludge is used as the input sludge of the sequencing batch reactor containing the above-mentioned cultivated and domesticated acid-producing bacteria, and a semi-continuous operation mode is adopted to discharge a certain volume of treated sewage instantaneously every day. The mud-water mixture of mud enters an equal volume of sewage treatment plant sludge. Pre-stir for 10 minutes before each sludge discharge. Control the VS 15g/L entering the sludge, VS/TS=0.7, SRT 6d, the stirring method during the hydrolysis and acidification of the sludge is the same as the above-mentioned stirring method in the cultivation and acclimation stage of acid-producing bacteria, the temperature is 20°C, and the pH value in the reactor depends on The acid-producing bacteria in the reactor and the volatile acid and alkalinity they produce are naturally maintained at 6.0, without additional adjustment and control.

The discharged mud-water mixture enters the sedimentation tank and settles for 2 hours. The supernatant of the sedimentation tank is recycled as the carbon source of the urban sewage biological nitrogen and phosphorus removal process, and the settled waste sludge is discharged.

Example 15

Stirring time 7min, SRT 4d, other are with embodiment 14.

Example 16

Stirring time 5min, SRT 3d, other are with embodiment 14.

Example 17

The stirring interval time is 50 minutes, the stirring time is 7 minutes, the VS entering the sludge is 20g/L, the SRT is 4 days, and the temperature is 23°C. The pH value in the reactor is naturally maintained at 6.5 by the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced by it. , other with embodiment 14.

Example 18

The stirring interval is 40min, the SRT is 3d, the pH value in the reactor is naturally maintained at 6.94 depending on the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced by it, the temperature is 25°C, and the others are the same as in Example 17.

The volatile acid concentration in the mud-water mixture after hydrolysis and acidification treatment was 3861mg/L, the acid production of the sludge was 0.19gVFA/gVS, and the removal rate of VS was 35%.

Example 19

The stirring interval time is 50 minutes, the stirring time is 5 minutes, the VS entering the sludge is 25g/L, and the SRT is 4 days. The pH value in the reactor is naturally maintained at 6.5 depending on the acid-producing bacteria in the reactor and the volatile acid and alkalinity produced by it. Others are implemented in the same way. Example 18.

Example 20

The stirring interval was 60 minutes, and the stirring time was 5 minutes. The pH value in the reactor was naturally maintained at 7.0 by acid-producing bacteria and the volatile acid and alkalinity produced in the reactor, and the others were the same as in Example 18.

Example 21

The hydrolytic acidification reactor adopts a sequencing batch reactor, and the return sludge from the aeration tank of the sewage treatment plant is placed in the sequencing batch reactor for inoculation, and the amount of inoculated sludge is 50% of the reactor volume. After inoculation, add carbohydrate organic waste water as the medium, carry out mechanical stirring and air stirring in the sequencing batch reactor at room temperature, both at the same time, stirring once every 60 minutes, each stirring time is 5 minutes, and the mechanical stirring intensity is 15W /m ³ , the amount of air stirred by air is 0.14m ³ /m ³ cell volume·min, so as to maintain the micro-aerobic condition of DO in the reactor at 0.8mg/L. The cultivation and domestication of acid-producing bacteria generally takes 7 to 14 days. No sludge is discharged during the cultivation process. The supernatant is discharged after stopping stirring and standing for 0.5 hours every day. Loop operation. The COD concentration and volume of carbohydrate organic wastewater added every day are determined by the organic loading rate and hydraulic retention time. The organic loading rate is 4gCOD/L·d, and the hydraulic retention time is 4d. When the volatile acid concentration in the hydrolysis acidification reactor reaches above 3000mg/L, the cultivation and acclimation of acid-producing bacteria is completed.

After the acid-producing bacteria have been cultivated and domesticated, the sewage treatment plant sludge is used as the input sludge of the sequencing batch reactor containing the above-mentioned cultivated and domesticated acid-producing bacteria, and a semi-continuous operation mode is adopted to discharge a certain volume of treated sewage instantaneously every day. The mud-water mixture of mud enters an equal volume of sewage treatment plant sludge. Pre-stir for 10 minutes before each sludge discharge. Control the VS 15g/L entering the sludge, VS/TS=0.65, SRT 6d, the stirring method during the hydrolysis and acidification of the sludge is the same as the above-mentioned stirring method in the cultivation and acclimation stage of acid-producing bacteria, the temperature is 20°C, and the pH value in the reactor depends on The acid-producing bacteria in the reactor and the volatile acid and alkalinity they produce are naturally maintained at 6.5, without additional adjustment and control.

The discharged mud-water mixture enters the sedimentation tank and settles for 2 hours. The supernatant of the sedimentation tank is recycled as the carbon source of the urban sewage biological nitrogen and phosphorus removal process, and the settled waste sludge is discharged.

Claims (3)

1. A microaerobic hydrolysis acidification method for treating sludge, comprising the following steps: a) Inoculate the aerobic sludge from the sewage treatment plant accounting for 50% to 70% of the reactor volume in the hydrolytic acidification reactor, and add carbohydrate organic waste water as the medium, and carry out mechanical stirring and air stirring, both at the same time , stirring once every 40-60 minutes, each stirring time is 5-10 minutes, the mechanical stirring intensity is 10-15W/m ³ , and the air volume of air stirring is 0.06-0.14m ³ /(m ³ pool volume min), so as to maintain hydrolysis and acidification Dissolved oxygen DO in the reactor is under micro-aerobic conditions of 0.4-0.8 mg/L; no sludge is discharged during the cultivation and acclimation process, only the supernatant is discharged intermittently, and after the supernatant is discharged, an equal volume of carbohydrate-based organic wastewater is added , stop stirring before discharging the supernatant, settle for 0.5-1h, and cycle; the COD concentration and volume of carbohydrate organic wastewater added every day are determined by the organic load rate and hydraulic retention time, and the organic load rate is 3-4gCOD/(L·d ), the hydraulic retention time is 3 to 4 days; when the volatile acid concentration in the hydrolytic acidification reactor reaches 3000mg/L or more, the cultivation and acclimation of acid-producing bacteria is completed; b) Use sewage treatment plant sludge with a volatile solid concentration of 15-25g/L and a volatile solid concentration/total solid concentration ratio greater than 0.5 as incoming sludge, and enter step a) into the reactor in which acid-producing bacteria have been cultivated and domesticated In the process, mechanical stirring and air stirring are carried out at the same time, stirring once every 40-60 minutes, each stirring time is 5-10 minutes, the mechanical stirring intensity is 10-15W/m ³ , and the air stirring air volume is 0.06-0.14m ³ / (m ³ tank capacity min); the sludge entering the reactor is discharged after the solid residence time of 3-6 days is met, and the sludge is stirred for 5-10 minutes before the sludge is discharged every day, and the mud-water mixture rich in volatile acids is discharged, and at the same time, it is added Equal volume of new sewage treatment plant sludge, cycle operation; c), the volatile acid-rich mud-water mixture discharged from step b) enters the sedimentation tank for mud-water separation, the supernatant of the sedimentation tank is recovered as a carbon source for the urban sewage biological denitrification and phosphorus removal process, and the deposited waste sludge is directly discharged. 2. The microaerobic hydrolysis acidification method for sludge treatment according to claim 1, characterized in that the hydrolysis acidification reactor is carried out at 20°C to 25°C for hydrolysis acidification. 3. The method for treating sludge with microaerobic hydrolysis and acidification according to claim 1, characterized in that the hydraulic retention time of the mud-water mixture entering the sedimentation tank for mud-water separation is 1 to 2 hours.