阅读说明：本技术 一种城市污泥厌氧消化处理方法 (Anaerobic digestion treatment method for municipal sludge ) 是由 田楠林 马达 崔爱民 单海波 李丽 李伟 于 2021-09-15 设计创作，主要内容包括：本申请涉及污泥环保处理的领域,更具体地说,它涉及一种城市污泥厌氧消化处理方法,包括如下步骤：S1：将污泥浆化、均质调配制备成待用泥；S2：将待用泥进行消化处理,制成预处理污泥；S3：将复合药剂B加入预处理污泥中,搅拌混合制得复处理污泥；复合药剂B由聚硅酸氯化铁、淀粉或者改性淀粉、壳聚糖、硅烷偶联剂、氯化钙混合组成；每100吨预处理污泥中添加复合药剂B的体积为4.2m??-4.4m??；S4：将复处理污泥进行脱水处理,得到固态污泥和消化液,将固态污泥堆置、风干；将消化液通过AAO工艺处理。本申请的制备方法具有提高对城市污泥厌氧消化处理过程中的脱水效果的优点。(The application relates to the field of sludge environment-friendly treatment, in particular to an anaerobic digestion treatment method for municipal sludge, which comprises the following steps: s1: slurrying and homogenizing sludge to prepare sludge for later use; s2: carrying out digestion treatment on the sludge to be used to prepare pretreated sludge; s3: adding the compound agent B into the pretreated sludge, and stirring and mixing to obtain the compound treated sludge; the compound agent B is formed by mixing poly-ferric chloride silicate, starch or modified starch, chitosan, a silane coupling agent and calcium chloride; carrying out high-speed labor at 4.2m and 4.4m respectively according to the volume of the compound medicament B added into each 100 tons of pretreated sludge; s4: carrying out dehydration treatment on the secondary sludge to obtain solid sludge and digestive juice, and stacking and air-drying the solid sludge; the digestive juice is treated by AAO process. The preparation method has the advantage of improving the dehydration effect in the anaerobic digestion treatment process of the municipal sludge.)

1. A municipal sludge anaerobic digestion treatment method is characterized in that: the method comprises the following steps:

s1: slurrying and homogenizing and blending the sludge to prepare sludge for standby;

s2: digesting the sludge to be used prepared in the step S1 to prepare pretreated sludge;

s3: adding the compound agent B into the pretreated sludge obtained in the step S2, and stirring and mixing for 28-32 min to obtain the compound sludge; the compound medicament B is prepared from poly-ferric chloride silicate, starch or modified starch, chitosan, a silane coupling agent and calcium chloride according to the mass ratio (6-8): (5-6): (2-3): (1.8-2.2): (4-6); carrying out high-speed labor at 4.2m and 4.4m respectively according to the volume of the compound medicament B added into each 100 tons of pretreated sludge;

s4: dehydrating the re-treated sludge obtained in the step S3 to obtain solid sludge and digestive juice, stacking the solid sludge and air-drying; the digestive juice is treated by AAO process.

2. The municipal sludge anaerobic digestion treatment method according to claim 1, wherein: in the step S3, after the composite medicament B is added into the pretreated sludge, a composite medicament A is also added, wherein the composite medicament A is prepared from polyaluminium sulfate, polyferric sulfate, polyacrylamide and poly dimethyl diallyl ammonium chloride according to the mass ratio of (7-8): (9-10): (2-3): (1-2); and carrying out thin film planting at the length of 0.7-0.9 m according to the volume of the compound medicament A added in each 100 tons of the pretreated sludge.

3. The municipal sludge anaerobic digestion treatment method according to claim 2, wherein: in the step S3, after the compound agent B and the compound agent a are added to the pretreated sludge, an alkali neutralizer is added to the pretreated sludge; and 1.4-1.6 tons of alkali neutralizing agent is added into each 100 tons of the pretreated sludge.

4. The municipal sludge anaerobic digestion treatment method according to claim 3, wherein: the alkali neutralizing agent is any one of lime and calcium hydroxide.

5. The municipal sludge anaerobic digestion treatment method according to claim 1, wherein: the preparation method of the polysilicate ferric chloride in the compound medicament B comprises the following steps:

1) mixing ferric chloride and water glass to prepare a standby liquid, wherein Fe in the standby liquid³⁺The molar concentration of the compound is 4-5 percent; SiO in the standby liquid₂With Fe³⁺In a molar ratio of 1: (0.9-1.2);

2) standing the standby liquid prepared in the step 1) for 0.5-1 h to obtain the compound.

6. The municipal sludge anaerobic digestion treatment method according to claim 1, wherein: the silane coupling agent is at least one of gamma-aminopropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane.

7. The municipal sludge anaerobic digestion treatment method according to claim 6, wherein: the silane coupling agent is prepared from gamma-aminopropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane in a mass ratio of 1: (1-2).

8. The municipal sludge anaerobic digestion treatment method according to claim 1, wherein: step S2, in the process of digesting the mud for later use, the mud for later use is sealed and stirred for 5 to 6 days at the temperature of 45 to 50 ℃ to obtain high-temperature hydrolysis mud; and then cooling the high-temperature hydrolysis sludge to 35-37 ℃, and simultaneously carrying out sealed stirring for 23-24 days to obtain the pretreated sludge.

9. A composite flocculant for anaerobic digestion treatment of municipal sludge is characterized in that: the composite material is prepared from poly-ferric chloride silicate, starch or modified starch, chitosan, a silane coupling agent and calcium chloride according to the mass ratio of (6-8): (5-6): (2-3): (1.8-2.2): (4-6).

Technical Field

The application relates to the field of sludge environment-friendly treatment, in particular to an anaerobic digestion treatment method for municipal sludge.

Background

The urban sludge generates a large amount of urban sludge every day, the urban sludge has high water content, contains a large amount of organic matters, heavy metals and pathogens, can be decomposed and smelly when not being treated in time, and can reduce the pollution of the urban sludge and improve the recycling rate of the urban sludge after the urban sludge is subjected to anaerobic digestion treatment along with the vigorous development of the national circular economy; the sludge dewatering is an important step in the anaerobic digestion treatment of the sludge, a large amount of moisture is removed from the dewatered sludge, the liquid sludge is converted into the semisolid sludge, and the separated moisture and the semisolid sludge can be respectively recycled, so that the recycling effect of the sludge is improved, and the pollution to the environment caused by the direct discharge of the sludge is reduced, therefore, the recycling effect of the subsequent sludge is directly influenced by the dewatering effect of the municipal sludge in the anaerobic digestion treatment process of the municipal sludge.

Disclosure of Invention

In order to improve the dehydration effect in the anaerobic digestion treatment process of municipal sludge, the application provides an anaerobic digestion treatment method of municipal sludge.

The anaerobic digestion treatment method for the municipal sludge adopts the following technical scheme:

a municipal sludge anaerobic digestion treatment method comprises the following steps:

s1: slurrying and homogenizing and blending the sludge to prepare sludge for standby;

s2: digesting the sludge to be used prepared in the step S1 to prepare pretreated sludge;

s3: adding the compound agent B into the pretreated sludge obtained in the step S2, and stirring and mixing for 28-32 min to obtain the compound sludge; the compound medicament B is prepared from poly-ferric chloride silicate, starch or modified starch, chitosan, a silane coupling agent and calcium chloride according to the mass ratio (6-8): (5-6): (2-3): (1.8-2.2): (4-6); the volume of the compound medicament B added in each 100 tons of pretreated sludge is 4.2m³-4.4m³；

S4: dehydrating the re-treated sludge obtained in the step S3 to obtain solid sludge and digestive juice, stacking the solid sludge and air-drying; the digestive juice is treated by AAO process.

By adopting the technical scheme, the composite medicament B consisting of the poly-silicate ferric chloride, the starch or the modified starch, the chitosan, the silane coupling agent and the calcium chloride is added, and the poly-silicate ferric chloride can neutralize the electrical property of the pretreated sludge while flocculating the pretreated sludge, but is not easy to biodegrade and has certain pollution to the environment; the starch or modified starch and chitosan as the flocculating agent have the advantages of high precipitation speed and environmental friendliness; the calcium chloride is added into the pretreated sludge, so that chloride ions with sterilization and disinfection effects can be released, cell walls of bacteria in the pretreated sludge are damaged, substances in the bacteria cells are released, and the subsequent dehydration effect on the pretreated sludge is improved; the silane coupling agent is added to improve the dispersibility of the polysilicate ferric chloride, the starch or the modified starch, the chitosan and the calcium chloride in the pretreated sludge, so that the flocculation sedimentation effect of the pretreated sludge is better; through the combination and compounding of all the components in the compound agent B, the pretreated sludge is quickly flocculated, and meanwhile, in the subsequent dehydration treatment, the gap water and the water on the surface of the flocculated pretreated sludge can be quickly separated, so that the dehydration effect on the sludge is improved.

Preferably, in step S3, after the compound agent B is added to the pretreated sludge, a compound agent a is further added, wherein the compound agent a is prepared from polyaluminium sulfate, polyferric sulfate, polyacrylamide and poly dimethyl diallyl ammonium chloride according to a mass ratio of (7-8): (9-10): (2-3): (1-2); the volume of the compound medicament A added in each 100 tons of the pretreated sludge is 0.7m³-0.9m³。

By adopting the technical scheme, the composite medicament A consisting of polyaluminium sulfate, polyferric sulfate, polyacrylamide and poly dimethyl diallyl ammonium chloride is added, the polyaluminium sulfate and the polyferric sulfate are used as inorganic flocculating agents, the polyacrylamide is used as an organic flocculating agent, and the pretreated sludge is added together, so that the pretreated sludge is not easily influenced by a pH value when being quickly flocculated and purified, and the pollution of the flocculated pretreated sludge to the environment is reduced; the poly dimethyl diallyl ammonium chloride can also flocculate the pretreated sludge, has no pollution to the environment and is beneficial to the composting treatment of the subsequent pretreated sludge; through the synergistic effect of the compound medicament A and the compound medicament B, the flocculation effect on the pretreated sludge is further improved, the dehydration effect of the pretreated sludge after flocculation is further improved, and meanwhile, the subsequent composting treatment of the pretreated sludge is facilitated.

Preferably, in step S3, after the compound chemical B and the compound chemical a are added to the pretreated sludge, an alkali neutralizing agent is further added to the pretreated sludge; and 1.4-1.6 tons of alkali neutralizing agent is added into each 100 tons of the pretreated sludge.

By adopting the technical scheme, the composite medicament A and the composite medicament B both have certain acidity, so that equipment and pipelines can be corroded in the process of treating the pretreated sludge, the acidity of the composite medicament A and the composite medicament B is neutralized by adding an alkali neutralizing agent, and the corrosion damage to the equipment and the pipelines in the flocculation and sedimentation process of the pretreated sludge is reduced.

Preferably, the alkali neutralizing agent is any one of quicklime and calcium hydroxide.

By adopting the technical scheme, as the quicklime and the calcium hydroxide both have better alkalinity, after being matched with the compound medicament A and the compound medicament B and added into the pretreated sludge, the pH value of the pretreated sludge is adjusted, and the damage of the flocculation process to equipment and pipelines is reduced; meanwhile, calcium carbonate can be formed in the pretreated sludge by the quicklime and the calcium hydroxide, so that a particle structure is formed, and the flocculation sedimentation rate of the pretreated sludge is accelerated.

Preferably, the preparation method of the polysilicate ferric chloride in the compound medicament B comprises the following steps:

1) mixing ferric chloride and water glass to prepare a standby liquid, wherein Fe in the standby liquid³⁺The molar concentration of the compound is 4-5 percent; SiO in the standby liquid₂With Fe³⁺In a molar ratio of 1: (0.9-1.2);

2) standing the standby liquid prepared in the step 1) for 0.5-1 h to obtain the compound.

By adopting the technical scheme, the main component in the water glass is sodium silicate, and ferric chloride and the sodium silicate in the water glass are mixed and reacted to synthesize the poly-silicate ferric chloride, so that the poly-silicate ferric chloride flocculates the pretreated sludge; when SiO is present₂With Fe³⁺When the concentration of the prepared solution is too high, the storage period of the generated sodium polysilicate chloride is short; when SiO is present₂With Fe³⁺When the concentration in the solution is too low, the generation amount of the polysilicate ferric chloride is small, and the subsequent flocculation effect is influenced. While regulating SiO₂With Fe³⁺The molar ratio of (A) to (B) and the molar concentration of the solution in the stock solution, so that the prepared polysilicate ferric chloride has good flocculation effect and good storage resistance.

Preferably, the silane coupling agent is composed of at least one of gamma-aminopropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane.

By adopting the technical scheme, at least one of gamma-aminopropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane is added into the pretreated sludge, and the surface groups of the gamma-aminopropyltriethoxysilane and the gamma-glycidoxypropyltrimethoxysilane can be combined with ferric polysilicate chloride, starch or modified starch, chitosan and calcium chloride, so that the dispersibility of the ferric polysilicate chloride, the starch or the modified starch, the chitosan and the calcium chloride in the pretreated sludge is improved, the flocculation effect on the pretreated sludge is improved, and the subsequent dehydration effect is improved.

Preferably, the silane coupling agent is prepared from gamma-aminopropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane in a mass ratio of 1: (1-2) preparing.

By adopting the technical scheme, the gamma-aminopropyltriethoxysilane and the gamma-glycidoxypropyltrimethoxysilane can interact with hydroxyl in inorganic matters and long molecular chains in organic polymers, the dispersibility and compatibility of the organic matters and the inorganic matters in the pretreated sludge are improved, and the flocculation and subsequent dehydration effects of the pretreated sludge are further improved by compounding the gamma-aminopropyltriethoxysilane and the gamma-glycidoxypropyltrimethoxysilane.

Preferably, in the step S2, in the process of digesting the sludge to be used, the sludge to be used is sealed and stirred for 5 to 6 days at the temperature of 45 to 50 ℃ to obtain high-temperature hydrolysis sludge; and then cooling the high-temperature hydrolysis sludge to 35-37 ℃, and simultaneously carrying out sealed stirring for 23-24 days to obtain the pretreated sludge.

By adopting the technical scheme, the mud to be used is stirred at the temperature of 45-50 ℃, and because the temperature of 45-50 ℃ is suitable for the growth of hydrolytic acidification bacteria and simultaneously inhibits the growth of methane bacteria, the hydrolytic acidification bacteria can promote the hydrolytic acidification process of the mud to be used, macromolecular substances which are difficult to be degraded biologically in the mud to be used are converted into micromolecular substances which are easy to be degraded biologically, the micromolecule is further converted into volatile fatty acid, and simultaneously a large amount of soluble organic matters are generated in the mud to be used, and the substances can provide a high-quality carbon source for biological denitrification; and then, the temperature is kept at 35-37 ℃ by cooling, the high-temperature hydrolysis sludge is hermetically stirred to promote the growth of methane bacteria, and the methane bacteria promote the decomposition of the high-temperature hydrolysis sludge and generate methane gas, so that the methane can be recovered subsequently. Through the regulation to the temperature in the mud digestion treatment for use, form biological phase separation through the temperature classification for different microorganisms all can grow under its suitable temperature, make for use mud has better anaerobic digestion effect.

In a second aspect, the application provides a composite flocculant for anaerobic digestion treatment of municipal sludge, which adopts the following technical scheme:

a composite flocculant for anaerobic digestion treatment of municipal sludge is prepared from poly-ferric chloride silicate, starch or modified starch, chitosan, a silane coupling agent and calcium chloride according to the mass ratio of (6-8): (5-6): (2-3): (1.8-2.2): (4-6).

By adopting the technical scheme, the flocculating agent has the advantages of high flocculating speed and environmental friendliness to sludge due to the combined action of the poly-ferric chloride silicate and the starch or the modified starch and the chitosan; the calcium chloride can release chloride ions to carry out wall breaking treatment on bacterial cells in the sludge, so that the subsequent dehydration effect of the sludge is improved; the silane coupling agent is added to promote the dispersibility of the polysilicate ferric chloride, the starch or the modified starch, the chitosan and the calcium chloride in the sludge and improve the flocculation effect of the sludge, and the components in the composite flocculant are compounded according to the proportion, so that the prepared composite flocculant has a good flocculation effect on the sludge.

In summary, the present application has the following beneficial effects:

according to the method, the composite medicament A, the composite medicament B and the alkali neutralizer are added into the pretreated sludge after digestion treatment, and the pretreated sludge is quickly flocculated under the combined action of the composite medicament A and the composite medicament B, so that the pollution of the flocculation process to the environment is reduced, the subsequent dehydration effect on the pretreated sludge is improved, and the dehydrated sludge is convenient for composting; the addition of the alkali neutralizing agent is used for neutralizing the acidity of the composite medicament A and the composite medicament B, so that when the pretreated sludge is subjected to flocculation treatment, the damage to equipment and pipelines is reduced.

Detailed Description

The present application will be described in further detail with reference to examples.

In the following examples, the water content of the sludge used in step S1 of the present application is 80% to 86%, the sludge needs to be diluted before slurrying in step S1, preferably, the sludge is diluted by using gravity-concentrated sludge with a water content of 97% to 98.5%, the water content of the sludge after dilution and slurrying is 91% to 92%, and the solid content of the sludge for standby after homogenizing and blending is 8%;

the compound agent A consists of polyaluminium sulfate, polyferric sulfate, polyacrylamide and poly dimethyl diallyl ammonium chloride;

preferably, the polyaluminium sulfate used has a CAS number of 10043-03-1;

preferably, the purity of the used polymeric ferric sulfate is 99%;

preferably, the polyacrylamide used has a purity of 99%;

preferably, the poly dimethyl diallyl ammonium chloride used has a CAS number of 26062-79-3;

the compound medicament B consists of polysilicate ferric chloride, starch or modified starch, chitosan, a silane coupling agent and calcium chloride, preferably, the polysilicate ferric chloride is formed by polymerizing water glass and ferric chloride, preferably, the water glass is provided by chemical Limited of Jinan Xinglong Dai; the purity of the ferric chloride used is 99%;

the starch and the modified starch are common products in the field; preferably, when starch is used in the compound medicament B, the purity of the starch is 99.6%; preferably, when modified starch is used in the composite medicament B, the modified starch is preferably vulcanized starch, and the preparation method of the vulcanized starch comprises the following steps:

putting starch and water into a stirring barrel with a stirring paddle according to the mass ratio of 1:5, wherein the stirring speed of the stirring paddle is set to be 20r/min, and the stirring time is 30min, so as to prepare starch emulsion; then adding sulfur, and stirring for one hour under the condition that the stirring speed is 20r/min to obtain the product. The mass ratio of the sulfur to the starch is 20: 1.

Preferably, the used sulfur is industrial grade sulfur, and the purity is 99.5%;

preferably, the chitosan used has a CAS number of 25156-29-0; preferably, the silane coupling agent consists of gamma-aminopropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane; preferably, the gamma-aminopropyltriethoxysilane used has a CAS number of 919-30-2; preferably, the purity of the gamma-glycidoxypropyltrimethoxysilane used is 98%;

preferably, the calcium chloride used has a CAS number of 10035-04-8;

the alkali neutralizer is quicklime or calcium hydroxide, preferably, the purity of the quicklime is 98%; preferably, the particle size of the calcium hydroxide used is 200 meshes;

preferably, in the step S2 of digestion treatment, when preparing the high-temperature hydrolysis sludge, the pH value of the sludge to be used is kept at 6.0-7.5 when the sludge to be used is hermetically stirred for 5-6 days at the temperature of 45-50 ℃;

preferably, in the digestion treatment of the step S2, the temperature of the high-temperature hydrolysis sludge is reduced to 35-37 ℃, the high-temperature hydrolysis sludge is sealed and stirred for 23-24 days, and the pH value of the high-temperature hydrolysis sludge is kept to be 7-8.5 in the process, so that the pretreated sludge is obtained.

Preparation example

Polysilicic acid ferric chloride preparation example 1

The preparation method of the poly-ferric silicate chloride in the urban sludge anaerobic digestion treatment method comprises the following steps:

1. putting ferric chloride and water glass into a stirring barrel with a stirring paddle together, wherein the stirring speed of the stirring paddle is set to be 40r/min, and the stirring time is 20min, so as to prepare a standby liquid; fe in ferric chloride solution in standby solution³⁺The molar concentration of (a) is 4%; SiO in the standby liquid₂With Fe³⁺In a molar ratio of 1: 0.9.

2. standing the standby liquid prepared in the step 1 for 45min to obtain the compound.

Preparation example 2 of Polysilicic acid ferric chloride

The difference between the preparation method of the poly-ferric silicate chloride in the urban sludge anaerobic digestion treatment method and the preparation example 1 of the poly-ferric silicate chloride is that SiO in the standby solution prepared in the step 1₂With Fe³⁺In a molar ratio of 1: 1, the rest are the same as in preparation example 1 of polysilicate ferric chloride.

Preparation of Polyferric chloride silicate 3

The difference between the preparation method of the poly-ferric silicate chloride in the urban sludge anaerobic digestion treatment method and the preparation example 1 of the poly-ferric silicate chloride is that SiO in the standby solution prepared in the step 1₂With Fe³⁺In a molar ratio of 1: 1.2, the rest are the same as in preparation example 1 of polysilicate ferric chloride.

Preparation of Polyferric chloride silicate 4

The difference between the preparation method of poly-ferric silicate chloride in the municipal sludge anaerobic digestion treatment method and the preparation example 2 of poly-ferric silicate chloride is that Fe in the stock solution prepared in the step 1³⁺The molar concentration of (a) was 5%, and the rest was the same as in preparation example 2 of polysilicate ferric chloride.

Examples

Example 1

The urban sludge anaerobic digestion treatment method comprises the following steps:

1: putting the sludge with the water content of 83 percent and the gravity-concentrated sludge with the water content of 98 percent into a slurry machine together, mixing and slurrying for 20min, and preparing the spare sludge with the water content of 91 percent; placing the standby mud into a blending tank, and carrying out homogenizing blending treatment under the conditions that the pressure is 0.4Mpa and the temperature is 150 ℃ to prepare the standby mud;

2: putting the mud to be used prepared in the step 1 into a sealed hydrolysis reactor, and stirring for 30 days under the conditions that the temperature is 40 ℃ and the pH value is 7.0 to obtain pretreated sludge;

3: adding the pretreated sludge obtained in the step 2 into a stirring barrel with a stirring paddle, adding the compound medicament B while stirring, setting the stirring speed of the stirring paddle to be 30r/min, and stirring and mixing for 30min to obtain the retreated sludge; the compound medicament B is prepared from polysilicate ferric chloride, vulcanized starch, chitosan, a silane coupling agent and calcium chloride according to a mass ratio of 6: 5: 2: 2: 4, the used poly-ferric silicate chloride is the poly-ferric silicate chloride prepared in the preparation example 1 of poly-ferric silicate chloride; the silane coupling agent is gamma-aminopropyl triethoxysilane; the volume of the compound medicament B added in each 100 tons of pretreated sludge is 4.3m³；

4: performing dehydration treatment on the re-treated sludge obtained in the step 3 to obtain digestive juice and solid sludge, and stacking and air-drying the solid sludge; the digestive juice is treated by AAO process.

Example 2

The difference between the anaerobic digestion treatment method for municipal sludge in the embodiment and the embodiment 1 is that the composite reagent B used in the step 3 is prepared from poly-ferric chloride silicate, vulcanized starch, chitosan, a silane coupling agent and calcium chloride according to a mass ratio of 8: 6: 3: 2: 6, the rest being the same as in example 1.

Example 3

The difference between the anaerobic digestion treatment method for municipal sludge in the embodiment and the embodiment 1 is that the composite reagent B used in the step 3 is prepared from poly-ferric chloride silicate, vulcanized starch, chitosan, a silane coupling agent and calcium chloride according to a mass ratio of 7: 5.5: 2.5: 2: 5, the rest being the same as in example 1.

Example 4

The difference between the anaerobic digestion treatment method for municipal sludge in this example and example 3 is that the volume of the compound agent B added per 100 tons of pretreated sludge in step 3 is 4.2m³The rest is the same as in example 3.

Example 5

The difference between the anaerobic digestion treatment method for municipal sludge in this example and example 3 is that the volume of the compound agent B added per 100 tons of pretreated sludge in step 3 is 4.4m³The rest is the same as in example 3.

Example 6

The difference between the anaerobic digestion treatment method for municipal sludge in the embodiment and the embodiment 3 is that the composite reagent B used in the step 3 is prepared from poly-ferric chloride silicate, starch, chitosan, a silane coupling agent and calcium chloride according to a mass ratio of 7: 5.5: 2.5: 2: 5, the rest being the same as in example 3.

Example 7

The anaerobic digestion treatment method for municipal sludge in the embodiment is different from the embodiment 3 in that after the compound medicament B is added in the step 3, the compound medicament A is added, and the compound medicament A is prepared from polymeric aluminum sulfate, polymeric ferric sulfate, polyacrylamide and polydimethyldiallyl ammonium chloride according to the mass ratio of 7.5: 9.5: 2.5: 1.5; the volume of the compound medicament A added in each 100 tons of pretreated sludge is 0.8m³The rest is the same as in example 3.

Example 8

The difference between the anaerobic digestion treatment method for municipal sludge in the embodiment and the embodiment 7 is that the composite medicament A added in the step 3 is prepared from polyaluminium sulfate, polyferric sulfate, polyacrylamide and polydimethyldiallylammonium chloride according to the mass ratio of 7: 9: 2: 1, preparing a composition; the rest is the same as in example 7.

Example 9

The difference between the anaerobic digestion treatment method for municipal sludge in the embodiment and the embodiment 7 is that the composite medicament A added in the step 3 is prepared from polyaluminium sulfate, polyferric sulfate, polyacrylamide and polydimethyldiallylammonium chloride according to the mass ratio of 8: 10: 3: 2, the rest being the same as in example 7.

Example 10

The method for anaerobic digestion treatment of municipal sludge according to the present example is different from example 7 in that after the addition of the compound chemical B and the compound chemical a in step 3, an alkali neutralizing agent is added to the pretreated sludge, the alkali neutralizing agent used is lime, 1.5 tons of alkali neutralizing agent are added per 100 tons of pretreated sludge, and the rest is the same as in example 7.

Example 11

The method for anaerobic digestion treatment of municipal sludge according to this example is different from example 10 in that the alkali neutralizing agent added in step 3 is calcium hydroxide, and the rest is the same as in example 10.

Example 12

The method for anaerobic digestion treatment of municipal sludge according to this example is different from example 10 in that the silane coupling agent added in step 3 is γ -glycidoxypropyltrimethoxysilane, and the rest is the same as in example 10.

Example 13

The difference between the anaerobic digestion treatment method for municipal sludge in the embodiment and the embodiment 10 is that the silane coupling agent added in the step 3 is prepared from gamma-aminopropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane in a mass ratio of 1: 1.5, the rest being the same as in example 10.

Example 14

The urban sludge anaerobic digestion treatment method comprises the following steps:

1: putting the sludge with the water content of 83 percent and the gravity-concentrated sludge with the water content of 98 percent into a slurry machine together, mixing and slurrying for 20min, and preparing the spare sludge with the water content of 91 percent; placing the standby mud into a blending tank, and carrying out homogenizing blending treatment under the conditions that the pressure is 0.4Mpa and the temperature is 150 ℃ to prepare the standby mud;

2: putting the mud to be used prepared in the step 1 into a sealed hydrolysis reactor, and stirring for 5 days under the conditions that the temperature is 47 ℃ and the pH value is 6.0 to obtain high-temperature hydrolysis mud; then cooling the high-temperature hydrolysis sludge to 36 ℃, stirring for 23 days, and setting the pH value to 7 to obtain pretreated sludge;

3: adding the pretreated sludge obtained in the step 2 into a stirring barrel with a stirring paddle, sequentially adding the compound medicament B, the compound medicament A and the alkali neutralizer into the pretreated sludge while stirring, and stirring and mixing for 30min to obtain the composite treated sludge; the compound medicament A is prepared from polyaluminium sulfate, polyferric sulfate, polyacrylamide and poly dimethyl diallyl ammonium chloride according to a mass ratio of 7.5: 9.5: 2.5: 1.5; the compound medicament B is prepared from polysilicate ferric chloride, vulcanized starch, chitosan, a silane coupling agent and calcium chloride according to a mass ratio of 7: 5.5: 2.5: 2: composition 5, the used poly-ferric silicate chloride is the poly-ferric silicate chloride prepared in poly-ferric silicate chloride preparation example 1; the silane coupling agent is prepared from gamma-aminopropyltriethoxysilane and gamma-glycidoxypropyltrimethoxysilane in a mass ratio of 1: 1.5; the alkali neutralizing agent is quicklime; the volume of the compound medicament A added in each 100 tons of pretreated sludge is 0.7m³The volume of the compound medicament B is 4.2m³The mass of the alkali neutralizing agent is 1.5 t;

4: performing dehydration treatment on the re-treated sludge obtained in the step 3 to obtain digestive juice and solid sludge, and stacking and air-drying the solid sludge; the digestive juice is treated by AAO process.

Example 15

The difference between the anaerobic digestion treatment method for municipal sludge in the embodiment and the embodiment 14 is that the sludge to be used is put into a sealed hydrolysis reactor in the step 2, and is stirred for 5 days under the conditions that the temperature is 47 ℃ and the pH value is 7.5, so as to obtain high-temperature hydrolysis sludge; then cooling the high-temperature hydrolysis sludge to 36 ℃, stirring for 23 days, and setting the pH value to 8.5 to obtain pretreated sludge; the rest is the same as in example 14.

Example 16

The municipal sludge anaerobic digestion treatment method of this example is different from example 15 in that the ferric polysilicate chloride added in step S4 is the ferric polysilicate chloride prepared in the ferric polysilicate chloride preparation example 2, and the rest is the same as in example 15.

Example 17

The municipal sludge anaerobic digestion treatment method of this example is different from example 15 in that the ferric polysilicate chloride added in step S4 is the ferric polysilicate chloride prepared in the ferric polysilicate chloride preparation example 3, and the rest is the same as in example 15.

Example 18

The municipal sludge anaerobic digestion treatment method of this example is different from example 15 in that the ferric polysilicate chloride added in step S4 is the ferric polysilicate chloride prepared in the ferric polysilicate chloride preparation example 4, and the rest is the same as in example 15.

Comparative example

Comparative example 1

The comparative example is different from example 1 in that the composite agent B added in step 3 is prepared from ferric polysilicate chloride, vulcanized starch, chitosan, gamma-aminopropyltriethoxysilane and calcium chloride according to the mass ratio of 9; 4: 5: 1: 2, preparing a composition; the rest is the same as in example 1.

Comparative example 2

The difference between the comparative example and the example 1 is that the composite medicament B added in the step 3 is prepared from ferric polysilicate chloride, vulcanized starch, chitosan and gamma-aminopropyltriethoxysilane according to the mass ratio of 6: 5: 2: 2, preparing a composition; the rest is the same as in example 1.

Comparative example 3

The difference between the comparative example and the example 1 is that the compound medicament B added in the step 3 is prepared from lime and ferric trichloride according to the mass ratio of 1: 2, preparing a composition; the rest is the same as in example 1.

Performance test

Respectively taking 100g of the retreated sludge prepared in the examples 1-18 and the comparative examples 1-3, respectively placing the retreated sludge prepared in the examples 1-18 and the comparative examples 1-2 in centrifugal tubes with the same specification, centrifuging for 10min at the rotating speed of 2000r/min, carefully pouring to remove supernatant liquid, avoiding the solid from being resuspended, weighing the mass of the supernatant liquid, recording as the liquid amount, calculating to obtain the solid amount, and calculating the solid content;

the solid content is [ (100-liquid amount)/100 ]. times.100%

TABLE 1 results of solid content test of the reprocessed sludge prepared in examples 1 to 18 and comparative examples 1 to 3

By combining examples 1-5 and comparative examples 1-3 and table 1, it can be seen that the addition of the compound agent B can promote the rapid separation of interstitial water and surface water of the flocculated sludge while rapidly flocculating the sludge, improve the dewatering effect on the sludge, and reduce the solid content of the dewatered sludge; when the added compound medicament B is prepared from polysilicate ferric chloride, vulcanized starch, chitosan, a silane coupling agent and calcium chloride according to a mass ratio of 7: 5.5: 2.5: 2: 5 when the amount of the compound agent B is 4.2m per 100 tons of sludge³The sludge dewatering effect is best, and the solid content of the dewatered sludge is lowest;

as can be seen by combining examples 7 to 9 and comparative examples 1 to 3 with Table 1, the volume of the composite agent A added per 100 tons of pretreated sludge was 0.8m³The composite medicament A is prepared from polyaluminium sulfate, polyferric sulfate, polyacrylamide and poly dimethyl diallyl ammonium chloride according to a mass ratio of 7.5: 9.5: 2.5: 1.5; the polyaluminium sulfate and the polyferric sulfate are used as inorganic flocculating agents, and the polyacrylamide is used as an organic flocculating agent; the poly dimethyl diallyl ammonium chloride can flocculate the sludge and has no pollution to the environment, the dehydration effect on the sludge is further improved through the synergistic effect of the composite agent A and the composite agent B, and the solid content of the dewatered sludge is reduced.

As can be seen by combining examples 14 to 15 and comparative examples 1 to 3 with Table 1, in the digestion treatment of sludge, the sludge was first stirred for 5 days at a temperature of 47 ℃ and a pH of 7.5 to obtain a high-temperature hydrolyzed sludge; then cooling the high-temperature hydrolysis sludge to 36 ℃, stirring, setting the pH value to 8.5, and keeping for 23-24 days to obtain pretreated sludge; the growth of hydrolytic acidification bacteria and methane bacteria in the sludge is promoted by changing the temperature, so that the dehydration effect of the subsequent sludge is improved.

As can be seen by combining examples 15-18 and Table 1, Fe in ferric chloride solution when preparing a stock solution of ferric polysilicate chloride³⁺The molar concentration of (a) is 4%; SiO in the standby liquid₂With Fe³⁺In a molar ratio of 1: 1, the prepared polysilicate ferric chloride has the best flocculation effect on the sludge.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.