阅读说明：本技术 一种污泥调理脱水方法及装置 (Sludge conditioning and dewatering method and device ) 是由 王毅力 高诗卉 于 2019-10-22 设计创作，主要内容包括：一种用于污泥调理脱水的方法及装置,该方法在调理脱水一体化装置中进行。调理过程产生羟基自由基氧化破解污泥,分解污泥胞外聚合物(EPS)并降解有机物,释放部分结合水,絮凝剂发挥电中和与吸附架桥作用,增大污泥絮体尺寸,提高污泥脱水性,然后在水平交流电场的电渗作用下,进一步去除自由水和部分结合水。该方法的实现步骤如下：(1)将污泥放置至水平电场阴极区,接通直流电源；(2)向污泥中投加过氧化氢；(3)向连续搅拌的污泥中通入臭氧进行反应；(4)向污泥中加入絮凝剂进行反应；(5)对污泥进行重力沉降一定时间后进行电渗脱水。本发明中调理步骤简单,脱水效果明显,调理药剂便宜,适用范围广,可降低污泥后续处理的费用。(A method and a device for conditioning and dehydrating sludge are carried out in a conditioning and dehydrating integrated device. The conditioning process generates hydroxyl free radical to oxidize and break the sludge, decompose Extracellular Polymer (EPS) of the sludge and degrade organic matters, release part of bound water, the flocculating agent plays a role in electrical neutralization and adsorption bridging, the size of sludge flocs is increased, the sludge dewatering performance is improved, and then the free water and part of bound water are further removed under the electroosmosis effect of a horizontal alternating current electric field. The method comprises the following implementation steps: (1) placing the sludge in a horizontal electric field cathode region, and switching on a direct current power supply; (2) adding hydrogen peroxide into the sludge; (3) introducing ozone into the continuously stirred sludge for reaction; (4) adding a flocculating agent into the sludge for reaction; (5) and performing electroosmosis dehydration on the sludge after gravity settling for a certain time. The invention has simple conditioning steps, obvious dehydration effect, cheap conditioning agent and wide application range, and can reduce the cost of the subsequent treatment of the sludge.)

1. The sludge conditioning and dewatering method is characterized by comprising the following steps:

(1) placing the sludge in a horizontal electric field cathode region, and placing an electrolyte solution in the horizontal electric field cathode region;

(2) switching on a direct current power supply to react for a certain time;

(3) adding hydrogen peroxide into the sludge while stirring;

(4) introducing ozone into the sludge, and reacting for a period of time;

(5) adding a flocculating agent into the sludge to uniformly mix the flocculating agent with the sludge;

(6) and carrying out gravity settling on the sludge for a certain time, and carrying out electroosmosis dehydration.

2. The method for conditioning and dewatering sludge according to claim 1, wherein the sludge is one or a mixture of primary sludge, activated sludge or digested sludge produced by municipal sewage treatment plants and sludge produced by biological treatment of industrial wastewater.

3. The sludge conditioning and dewatering method of claim 1, wherein the DC electric field in step (1) is divided into an anode region and a cathode region, and the operating voltage of the DC power supply is 2-60V.

4. The method for conditioning and dewatering sludge according to claim 1, wherein the sludge in the step (1) is electrified in the electric field for 2-20 minutes.

5. The sludge conditioning and dewatering method according to claim 1, wherein the hydrogen peroxide is added in the step (2) in a range of 0.57-9.5g/g dry weight of sludge; the dry weight of the sludge refers to the sludge dried at 105 ℃.

6. The sludge conditioning and dewatering method as claimed in claim 1, wherein the ozone flow rate in step (3) is in the range of 0.16-1.84L/min, the stirring intensity is 100-400r/min, and the reaction time is 5-40 min.

7. The sludge conditioning and dewatering method according to claim 1, wherein the flocculant in step (4) is an inorganic iron salt or an organic polyacrylamide, the dosage is 0.1-0.4g/g dry weight of sludge and 0.2-0.5 g/g dry weight of sludge, and the stirring intensity and time are respectively: rapidly stirring for 1-5min with the stirring intensity of 100-; slowly stirring for 5-10min with stirring intensity of 20-70 r/min; the dry weight of the sludge refers to the sludge dried at 105 ℃.

8. The sludge conditioning and dewatering method of claim 1, wherein the electroosmotic dewatering in step (5) has a working voltage of 10-60V and a dewatering time of 20-120min, and the water content of the dewatered sludge can be reduced to 60% -80%.

9. A method and equipment for sludge dehydration comprise the sludge conditioning and the sludge horizontal electric field dehydration process, and are characterized in that:

sludge conditioning and dewatering equipment: a stirring device (8) and an ozone introducing device (9), which are arranged in the reaction device when in use and are used for conditioning the sludge according to the claim 1; the direct current power supply (1) is used for providing driving power required by electric field dehydration; the reaction device (3) is used for conditioning sludge and performing electric dehydration; a cathode area (10) in the reaction device is used for containing sludge to be dehydrated, and an anode area (2) is used for containing electrolyte solution; a filter plate (6) is arranged between the cathode area and the anode area, filter cloth (7) is fixed, and a certain interval is ensured between the filter cloth and the anode plate (4) and between the filter cloth and the cathode plate (5); after conditioning is finished, electric dehydration is continuously carried out, and the water removed in the dehydration process enters the filtrate cavity through the filter cloth at the cathode and finally flows out from the collection port.

Technical Field

The invention relates to a conditioning and dewatering method for sludge disintegration and flocculation, belonging to the technical field of environmental protection.

Background

In recent years, with the rapid development of economy in China, the production amount of sewage also tends to increase rapidly, and a large amount of excess sludge is produced by the sewage through biological treatment. According to prediction, the sludge yield of China breaks through 6000 million tons/year (the water content is calculated according to 80%) by 2020. The excess sludge has the characteristics of high water content (more than or equal to 95 percent), fine particles and high compressibility, so that the excess sludge has poor dehydration performance and is difficult to separate sludge from water, and the difficulty of subsequent treatment and disposal is increased. In addition, the excess sludge contains a large amount of toxic substances such as organic substances, heavy metals, and bacterial pathogens, in addition to water, and also includes persistent organic substances having bioaccumulation and ecotoxicity. Therefore, the treatment and disposal of the excess sludge become a difficult problem in the environment and water supply and drainage industries of China. The action plan for preventing and treating water pollution issued in 2015 in China specially proposes that sludge treatment needs to be promoted, and sludge generated by sewage treatment facilities needs to be subjected to reduction, stabilization, harmless treatment and resource treatment. The reduction of the sludge is a premise for subsequent treatment, and the conditioning and dehydration of the sludge are key steps for realizing the reduction and are also the primary links of sludge treatment and disposal. Sludge conditioning is a key pretreatment step in order to achieve a reduction in the moisture content of the sludge. Generally, the conditioning of sludge can be classified into physical, chemical, and biological methods according to its conditioning mechanism. The chemical conditioning method has the advantages of simple operation, stable effect, low cost and the like, and is one of the most common conditioning methods at present.

The sludge needs to be dehydrated after conditioning in order to realize final reduction. The conventional sludge dewatering methods can be roughly classified into four types, i.e., natural drying, heat drying, mechanical dewatering, and electrical dewatering, and these methods may be used in combination. The electric dehydration is a method for enhancing the sludge dehydration performance by using an external electric field, the water removal is carried out on the inner surface and the outer surface of each flocculating constituent particle, the interstitial water and the free water are removed simultaneously, the particle density is uniformly increased, the sludge is subjected to chemical conditioning and then is subjected to electric dehydration, the advantages of good dehydration effect, stable operation, low operation energy consumption and the like are achieved, a safe and economic implementation scheme is provided for the treatment and disposal of the sludge of a sewage treatment plant, and a wide market is provided for the reduction, harmless treatment and resource application of the sludge.

Chinese patent application publication No. CN 106365412 a discloses a method for conditioning excess sludge of municipal sewage plants by ultrasound and Fenton cooperation, which comprises adjusting the pH of the sludge, adding a Fenton reagent, performing ultrasound treatment on the sludge, and reacting for a certain time after the ultrasound treatment. The method utilizes the effect of ultrasonic strengthening Fenton oxidation to break the sludge structure, reduces the energy consumption of ultrasonic conditioning and the consumption of Fenton reagent, and improves the dehydration performance of sludge. However, the method has long reaction time, the reaction condition of the Fenton reagent needs to be under the pH value of less than 4, the reaction condition is harsh, secondary pollution is easy to cause, and the method is not beneficial to the subsequent treatment of sludge.

Chinese patent application publication No. CN 106277660 a discloses a method for treating excess activated sludge by heterogeneous catalysis ozone, which utilizes an ozone catalyst composed of a carrier and an active metal component loaded on the carrier and ozone to decompose organic matters in the sludge, thereby reducing the mass and volume of the sludge. However, the method has the disadvantages of complex preparation of the ozone catalyst, complex process, long reaction time and low ozone utilization rate.

The Chinese patent application with the publication number of CN 110117149A discloses a catalytic oxidation type sludge conditioner and a sludge conditioning method. The method adds various chemical substances into the sludge, is easy to cause secondary pollution, is not beneficial to the subsequent treatment of the sludge, and has complicated process because the sludge needs to be transferred for mechanical pressure dehydration after being conditioned.

Accordingly, the invention aims to provide a sludge conditioning method with less secondary pollution, high efficiency, excellent effect and low economic cost aiming at the problems in the prior art.

Disclosure of Invention

1. The invention aims to provide a sludge conditioning method and equipment thereof aiming at the problems of insignificant dehydration effect, easy generation of secondary pollution and the like after the conventional sludge conditioning. The sludge treatment method has good effects on reducing the water content of the sludge, reducing the volume of the sludge, reducing the cost of sludge transportation and subsequent treatment and the like, and has the advantages of short reaction time, small secondary pollution, low economic cost, wide application range and the like.

2. The sludge conditioning device comprises a conditioning pool, a power supply, a mechanical stirrer, an ozone generator, an ozone detector and a gas flowmeter.

3. In order to achieve the purpose, the invention is realized by the main steps of pretreatment, oxidation conditioning, flocculation, electric dehydration and the like:

(1) placing the sludge in a cathode area of an electric field, placing an electrolyte solution in an anode area, switching on a direct current power supply and reacting for a certain time;

(2) adding a certain amount of hydrogen peroxide into the sludge while stirring;

(3) introducing ozone into the sludge, and reacting for a period of time;

(4) adding a flocculating agent into the sludge to uniformly mix the flocculating agent with the sludge;

(5) and carrying out gravity settling on the sludge, and carrying out electroosmosis dehydration for a certain time.

4. Particularly, the dewatered sludge to be conditioned in the step is residual activated sludge of an urban sewage treatment plant, and the water content is 97.00-99.99%, preferably 97.00-98.00%.

5. Particularly, the concentration of the hydrogen peroxide solution in the step is 30%, the adding amount is 0.57-9.5g/g dry weight of sludge, and preferably 3.8-9.5 g/g dry weight of sludge; the O3 flow is set to be 0.16-1.84L/min, and the optimized flow is 0.5-1.5L/min; the flocculating agent is preferably ferric chloride hexahydrate or cationic polyacrylamide, and the adding amount is respectively set to be 0.1-0.4g/g of dry sludge weight and 0.2-0.5 g/g of dry sludge weight, and is preferably 0.15-0.25 g/g of dry sludge weight and 0.25-0.4 g/g of dry sludge weight. (corresponding to the above)

6. The dry sludge refers to sludge dried at 105 ℃.

7. In particular, the reaction time after the direct current power supply is turned on in the step is 2 to 20 minutes.

8. In particular, the electrolyte solution in step (A) is preferably 0.05 to 0.5mol/L sodium chloride solution.

9. In particular, the gravity settling time in step (a) is set to 2-8 h.

10. In the above sludge dewatering method, the horizontal electric field dewatering device provides the electric field as a horizontal electric field.

11. Particularly, the horizontal electric field in the step is a constant voltage electric field, and the voltage of the power supply for dehydration is set to 10-60V.

12. Particularly, the dehydration time of the sludge horizontal electric field is set to be 20-120 min.

13. The sludge dewatering method and the device have the following advantages:

the conditioner has low cost and wide application range. The hydrogen peroxide solution and the ferric salt used in the method are common, easily available and low-cost agents, have good effect on municipal sludge with the water content of more than 90 percent, and are safe and efficient sludge conditioning methods.

14. The conditioning and dehydration processes are all in the same reaction device, and the operation is simple and convenient.

15. The reagent used in the conditioning part of the invention does not need to be prepared into solution, thus being simple and convenient.

16. The invention conditions that no secondary pollutant is generated by the reaction of ozone and hydrogen peroxide solution in the partial oxidation process.

17. The sludge conditioning method disclosed by the invention combines sludge disintegration and flocculation combined conditioning, and fully exerts the advantages of the sludge disintegration and the flocculation combined conditioning. Firstly, the hydroxyl free radical with strong oxidizing property is generated by the reaction of ozone and hydrogen peroxide under the condition of electrolysis in-situ alkali generation, and the extracellular polymeric structure in the sludge can be effectively destroyed, so that part of bound water is released. Secondly, after the flocculating agent is added, positive charges neutralize negative charges carried on the surface of the sludge, so that the Zeta potential of the sludge is increased, sludge flocs are increased, and the sludge dewatering performance is well improved.

18. The sludge conditioning method has good effect, the final water content of the sludge after dehydration treatment is reduced to be below 80 percent, the volume of the sludge is greatly reduced, and the difficulty of transportation and the occupied area of storage are reduced to a great extent.

19. The dehydration method and the device have low operation cost and improve the sludge dehydration efficiency. And has the characteristics of cleanness, safety and high efficiency, and is a green and environment-friendly sludge conditioning method.

Drawings

FIG. 1 is a schematic view of the integrated device for conditioning and dewatering of the present invention

Description of reference numerals: a direct current power supply; the anode area of the reaction device; thirdly, a reaction device; fourthly, an electrode anode; electrode cathode; sixthly, vertical isolation plates; seventhly, filtering cloth; eighthly, a mechanical stirrer; ninthly, introducing ozone into the device. Cathode region of R reaction device

Detailed Description

The invention will be described in detail below with reference to the drawings and examples, which are given by way of illustration only,

and do not set any limit to the scope of the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

Example 1 was carried out:

sludge to be dewatered is collected in a certain sewage treatment plant in Beijing, and the sewage treatment plant adopts the traditional activated sludge process to treat municipal sewage. The activated sludge collection point is positioned at a certain position on a return section from the secondary sedimentation tank to the aeration tank. The water content of the sludge is 98.92 percent, and the pH value is 6.87.

(1) Placing activated sludge in a cathode region of a horizontal pressurized electric field reactor, connecting the anode region and the cathode region of the reactor with the cathode and the anode of a power supply respectively, regulating the voltage to be 60V, and electrifying for 10 min;

(2) adding hydrogen peroxide solution with the concentration of 30 percent at 5.7g/g of sludge dry weight into the sludge under the stirring condition of 300 r/min;

(3) turning on an ozone generator, and adjusting a gas flowmeter to enable the flow of ozone to reach 1.5L/min;

(4) FeCl of 0.06g/g dry weight of sludge is added to the sludge₃·6H₂O, stirring at the speed of 200r/min for 1min, then stirring at the speed of 60r/min for 10min, and then standing for 30 min;

(5) and (3) performing gravity settling on the conditioned sludge for 2 hours, then continuing to perform horizontal electric field dehydration for 2 hours, collecting all filtrate after the reaction is finished, weighing the mass of the filtrate, collecting the sludge dehydrated in a sludge cavity after the reaction is finished, and measuring the water content of the sludge by using a gravimetric method.

The measurement results are shown in table 1.

Example 2 was carried out:

sludge to be dewatered is collected in a certain sewage treatment plant in Beijing, and the sewage treatment plant adopts the traditional activated sludge process to treat municipal sewage. The activated sludge collection point is positioned at a certain position on a return section from the secondary sedimentation tank to the aeration tank. The water content of the sludge is 98.63 percent, and the pH value is 6.73.

(1) Placing activated sludge in a cathode region of a horizontal pressurized electric field reactor, connecting the anode region and the cathode region of the reactor with the cathode and the anode of a power supply respectively, regulating the voltage to be 60V, and electrifying for 10 min;

(2) adding hydrogen peroxide solution with the concentration of 30 percent at 5.7g/g of sludge dry weight into the sludge under the stirring condition of 300 r/min;

(3) turning on an ozone generator, and adjusting a gas flowmeter to enable the flow of ozone to reach 1.5L/min;

(4) FeCl of 0.25g/g dry sludge weight was added to the sludge₃·6H₂O, stirring at the speed of 200r/min for 1min, then stirring at the speed of 60r/min for 10min, and then standing for 30 min;

(5) and (3) performing gravity settling on the conditioned sludge for 2 hours, then continuing to perform horizontal electric field dehydration for 2 hours, collecting all filtrate after the reaction is finished, weighing the mass of the filtrate, collecting the sludge dehydrated in a sludge cavity after the reaction is finished, and measuring the water content of the sludge by using a gravimetric method.

The measurement results are shown in table 1.

Example 3 of implementation:

sludge to be dewatered is collected in a certain sewage treatment plant in Beijing, and the sewage treatment plant adopts the traditional activated sludge process to treat municipal sewage. The activated sludge collection point is positioned at a certain position on a return section from the secondary sedimentation tank to the aeration tank. The water content of the sludge is 98.77 percent, and the pH value is 6.96.

(1) Placing activated sludge in a cathode region of a horizontal pressurized electric field reactor, connecting the anode region and the cathode region of the reactor with the cathode and the anode of a power supply respectively, regulating the voltage to be 60V, and electrifying for 10 min;

(2) adding hydrogen peroxide solution with the concentration of 30 percent at 3.8g/g of sludge dry weight into the sludge under the stirring condition of 300 r/min;

(3) turning on an ozone generator, and adjusting a gas flowmeter to enable the flow of ozone to reach 0.16L/min;

(4) adding CPAM with concentration of 0.1% into sludge, adding 0.06g/g sludge dry weight, stirring at 200r/min for 1min, stirring at 60r/min for 10min, and standing for 30 min;

(5) and (3) performing gravity settling on the conditioned sludge for 2 hours, then continuing to perform horizontal electric field dehydration for 2 hours, collecting all filtrate after the reaction is finished, weighing the mass of the filtrate, collecting the sludge dehydrated in a sludge cavity after the reaction is finished, and measuring the water content of the sludge by using a gravimetric method.

The measurement results are shown in table 1.

Comparative example 1:

the same procedure as in example 4 was repeated, except that the amount of hydrogen peroxide added was 1.9g/g dry weight of sludge.

Comparative example 2:

the flow rate of the deodorizing oxygen was set to 0.5L/min, and the rest was the same as in example 6.

Comparative example 3:

the same procedure as in example 1 was repeated except that CPAM was added in an amount of 0.

TABLE 1 sludge dewatering Effect of the invention

The detection result shows that:

1. the dehydration water content of the horizontal electric field after the oxidation-flocculation synergistic conditioning is reduced, and the dehydration performance of the sludge is improved.

2. The adding amount of the hydrogen peroxide is different in the conditioning process, and the dehydration effect is different.

3. The flow of ozone is different in the conditioning process, and the dehydration effect is different.

4. The types of the flocculating agents are different in the conditioning process, and the dewatering effect is different.

The addition amount of the flocculating agent is different in the conditioning process, and the dewatering effect is different.