CN108503173B

CN108503173B - Municipal activated sludge treatment catalyst, sludge treatment system and sludge treatment method

Info

Publication number: CN108503173B
Application number: CN201810265106.2A
Authority: CN
Inventors: 范宏; 梁明; 杨锦梁
Original assignee: Chengdu Chenghong Electromechanical Co ltd
Current assignee: Chengdu Chenghong Electromechanical Co ltd
Priority date: 2018-03-28
Filing date: 2018-03-28
Publication date: 2021-07-06
Anticipated expiration: 2038-03-28
Also published as: CN108503173A

Abstract

The invention discloses a municipal activated sludge treatment catalyst, a sludge treatment system and a sludge treatment method, which belong to the technical field of municipal engineering sludge treatment. The side wall of the catalytic body is provided with the plurality of through holes, so that a larger specific surface area can be obtained, the contact area of sludge and the catalytic body is increased, the reaction time is shortened, the self weight of the catalytic body is further reduced, the up-and-down back-and-forth movement speed of the catalytic body along with the mixture rolling in the reactor is increased, and the sludge treatment efficiency is improved.

Description

Municipal activated sludge treatment catalyst, sludge treatment system and sludge treatment method

Technical Field

The invention relates to the technical field of municipal engineering sludge treatment, in particular to a municipal activated sludge treatment catalyst, a sludge treatment system and a sludge treatment method.

Background

At present, the activated sludge process is a treatment method generally adopted by urban domestic sewage treatment plants, and has a history of nearly one hundred years. A large amount of sludge can be generated in the activated sludge process, the sewage treatment plant needs to perform concentration, dehydration, digestion and other modes on the generated sludge, the post-treatment of the treated sludge needs to be buried, anaerobically digested or incinerated, the complicated sludge treatment and treatment process needs very high cost as support, can account for 25% -60% of the total operation cost of the whole sewage treatment plant, and has very high cost, but the mode of burying and incinerating is adopted in the post-treatment in the prior art, and serious secondary pollution is caused.

Adopting a post-processing mode of landfill: the treatment method is simple, easy to implement, low in cost, free from high dehydration of the sludge and strong in adaptability. However, sludge landfills also have problems, particularly with respect to landfill leachate and gas formation. Leachate is a severely contaminated liquid that can contaminate groundwater environments if landfills are located or improperly operated. The gas produced by landfills is primarily methane, which can cause explosion and combustion if appropriate measures are not taken.

Adopting a post-treatment mode of incineration: after incineration treatment, the volume can be reduced by 85-95%, and the mass is reduced by 70-80%. The high-temperature incineration can also eliminate harmful germs and harmful substances in the sludge. The high-temperature incineration can quickly and effectively achieve the aims of sterilization and reduction of the sludge, and the product is sterile and odorless inorganic residue with zero water content. The polycyclic aromatic hydrocarbon pollutants do not exist any more, the content of other organic pollutants is almost zero, the volume of the sludge is greatly reduced, and no storage equipment is needed under severe weather conditions, so that the sludge is extremely convenient to treat finally. However, the disadvantages of sludge incineration are obvious, the pollutant generation amount is large, and although the pollutant discharge can be controlled by additional methods such as flue gas treatment and fly ash treatment, a large amount of capital investment is required, and the sludge incineration cost is increased.

Adopting a post-treatment mode of anaerobic digestion: anaerobic digestion is a sludge disposal method commonly used in the world at present, and compared with other methods, the method has the advantages of killing germs, reducing the volume of sludge, promoting the final stability of the sludge and the like, and can generate methane, recover energy and reduce energy consumption. From the aspects of economic development, resource development and utilization, ecological environment protection and the like, the anaerobic digestion not only achieves the purpose of sludge reduction, but also realizes the resource utilization of sludge, and is an important method for sludge disposal. In the whole anaerobic digestion process of the sludge, the hydrolysis process is slow in speed and is a speed-limiting stage, so that the defects of long retention time (generally over 30 days), low gas production and the like of the anaerobic digestion of the sludge are caused.

The main reason why the water content of the sludge after mechanical dehydration is high is that biological cells and colloids in the sludge contain a large amount of intracellular water (accounting for 70 percent of the total water content) which cannot be completely extruded by the pressure of the traditional mechanical dehydration, and meanwhile, the sludge has the water content of 60 to 65 percent and is in a sticky pulp shape, and water molecules are wrapped by a layer of colloid, and the area is called as a 'sticky phase area' of the sludge, which is the most difficult stage of sludge dehydration and is difficult to further remove by the traditional mechanical dehydration method. Therefore, special measures are needed to break the intercellular structure and the sludge 'viscose phase region' so that part of 'intracellular water' is discharged and filtered by a mechanical filter pressing mode.

Therefore, municipal works sludge treatment technical field is urgent to wait for the demand a sludge treatment system that can incessant operation of continuity, can solve the difficult problem how broken wall of microbial cell in the mud in short time, thereby realize broken wall of cell and release microbial cell inside water, can improve the rate of utilization of ozone again, can use less ozone and catalyst in order to reduce manufacturing cost when handling the mud of equal volume, do not leave chemical agent in the mud after the while handles, heavy metal etc. produces secondary pollution to the environment, then carry out filter-pressing and mummification, and can turn into the resource with it, realize municipal sludge innoxiousness, minimizing and the virtuous circle of utilization.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a municipal activated sludge treatment catalyst, a sludge treatment system and a sludge treatment method.

The invention is realized by the following technical scheme:

the municipal activated sludge treatment catalyst body takes a stainless steel material as a carrier, a noble metal oxide layer is loaded on the surface of the stainless steel material, and the noble metal oxide is solidified on the surface of the stainless steel material in a sintering or sputtering mode.

Preferably, the stainless steel material structure is a circular, rectangular or polygonal pipe body, a plurality of through holes are formed in the pipe wall of the pipe body, the diameter of the pipe body is 10 mm-50 mm, the wall thickness of the pipe body is 0.2 mm-3 mm, the length of the pipe body is 5 mm-50 mm, and the diameter of each through hole is 1 mm-10 mm.

Preferably, the stainless steel material structure is a hollow sphere, a plurality of through holes are formed in the spherical surface of the hollow sphere, the diameter of the sphere is 10-50 mm, the wall thickness of the sphere is 0.2-3 mm, and the diameter of each through hole is 1-10 mm.

Preferably, the noble metal oxide is any one or more of platinum oxide, rhodium oxide, palladium oxide and iridium oxide.

As another aspect of the invention, a municipal activated sludge treatment system is provided, which comprises at least two closed reactors communicated with each other, wherein the reactors are internally loaded with the municipal activated sludge treatment catalyst bodies;

the sewage pump is connected with an input port of the mixer through a pipeline, an air inlet pipeline for introducing ozone gas is arranged at the input port of the mixer, and the air inlet pipeline is connected with the ozone generator;

the delivery outlet of the mixer is connected with the top of any one of the at least two communicated closed reactors through a pipeline, and the communication mode among the reactors is as follows: the bottom of one reactor is communicated with the top of the other reactor through a pipeline, the bottom of the other reactor is connected with subsequent treatment equipment through a pipeline, and the maximum pore diameter of a discharge hole of the reactor is smaller than the minimum size of the catalyst body.

In the preferable scheme, the volume ratio of the catalyst body in the reactor to the reactor is 1-3: 10.

as another aspect of the present invention, there is provided a municipal activated sludge treatment method comprising the steps of:

step 1: pumping the residual sludge in the sludge pool into a mixer through a sewage pump, introducing ozone gas into the mixer to mix with the sludge in a gas-liquid manner, forming hydroxyl radicals by combining the ozone with hydrogen bonds in water to form a mixture of the ozone, the hydroxyl radicals and the sludge, then injecting the mixture into a closed reactor, a plurality of catalyst bodies are scattered in the reactor, the catalyst bodies are impacted by the mixture when the mixture is injected into the reactor, under the action of impact force, the mixture and the catalyst form a continuous mixing and stirring state in the reactor, the catalyst accelerates ozone in the mixture to form hydroxyl radicals, and the hydroxyl radicals and the ozone and microorganisms in the sludge generate oxidation reaction to kill bacteria and oxidize the microorganisms, promote the cell wall breaking of the microorganisms and release water in the microorganism cells, and realize harmless and quantitative reduction treatment of the sludge;

step 2: mechanically dehydrating the oxidized sludge, separating the sludge into a formed mud cake with the water content of 50-70% and a pressure filtrate, and feeding the separated pressure filtrate into a sewage biochemical treatment system;

and step 3: deeply dehydrating the mud cakes with the water content of 50-70% to generate mud cakes with the water content of not more than 30%;

and 4, step 4: granulating the mud cakes with the water content of not more than 30%;

and 5: and (3) granulating the mud cakes with the water content of not more than 30%, and fermenting to form the dried organic fertilizer.

Preferably, the step of adding ozone and sludge in the mixer to mix in step 1 specifically comprises: and (3) mixing gas with ozone concentration not lower than 80% with the sludge according to the volume ratio of 10: 0.1-1 for 2-5 minutes to kill bacteria in the sludge.

Preferably, the step of adding ozone and sludge in the mixer to mix in step 1 specifically comprises: and (2) mixing gas with ozone concentration not lower than 80% with sludge according to the volume ratio of 10: 1-4, wherein the mixing time is 2-5 minutes, oxidizing microorganisms in the sludge, breaking the walls of the microbial cells, opening micelles and releasing water in the microbial cells in the sludge.

Preferably, in step 2, the mechanical dewatering of the sludge is performed by: dewatering by adopting a membrane filter press, a plate-and-frame filter press or spiral compression equipment, and in the step 3, deeply dewatering the mud cake with the water content of 50% -70%: drying and dehydrating by adopting saturated steam.

Preferably, a flocculating agent with the mass accounting for less than or equal to 5 per mill is added into the sludge between the step 1 and the step 2.

Compared with the prior art, the invention has the following advantages and beneficial effects:

the municipal activated sludge treatment catalyst of the invention is characterized in that:

one is as follows: the municipal activated sludge treatment catalyst body adopts the stainless steel material as a carrier, and the precious metal oxide material is loaded on the surface of the stainless steel material in a high-temperature sintering or sputtering mode, so that the precious metal oxide material can form a compact layer on the surface of the stainless steel material in the high-temperature sintering or sputtering mode, the catalyst body is not easy to wear, and the service life of the catalyst body is prolonged.

The second step is as follows: when the traditional stainless steel material loaded with noble metal oxide material is used as a catalyst, most of the catalyst is in a particle form or is directly coated on the inner wall of a reactor, and the position of the catalyst is fixed in such a way that the catalyst is difficult to effectively contact with sludge, so that the fundamental problem that continuous feeding production cannot be carried out is caused. The catalyst body is a hollow tube body structure or a hollow sphere body structure, so when the material is continuously fed, the impact force of water flow and sludge can be contacted with the hollow catalyst body from multiple directions, thereby the catalyst body can be in a state of moving at high speed in the reactor, furthermore, the catalyst body is provided with a plurality of through holes, firstly, the lightweight design of the catalyst body can be further completed, the rapid movement of the catalyst body is further promoted, meanwhile, because the sludge contains a large amount of impurities, such as hair, plastic bags, fabrics, sanitary paper towels, sticky substances, grass roots and the like, the catalyst body is arranged into a tube body shape or a hollow sphere shape and is provided with a porous structure, so that the catalyst body is difficult to be intertwined with the impurities, the catalyst body can effectively and flexibly move in the reactor, and the purpose of rapid catalysis is finally achieved, by the mode, so that the catalytic reaction is completed within 2-5 min, and the material can be fed continuously under the condition of time control, thereby accelerating the treatment of sludge.

And thirdly: the catalyst body adopting the hollow pipe body structure or the hollow sphere structure has the advantages of easily available raw materials, low manufacturing cost, light weight, difficult deposition at the bottom of the reactor and capability of fully mixing with sludge in the reactor. A plurality of through holes are formed in the side wall of the pipe body and the spherical surface of the hollow sphere, so that a larger specific surface area can be obtained, the contact area of sludge and the catalytic body is increased, and the reaction time is shortened. The catalyst body uses a stainless steel material as a carrier, which has excellent corrosion resistance and wear resistance and is less susceptible to changes in pH and temperature than other metals. The stainless steel has very good physical and chemical stability. Unlike other iron-based materials, stainless steel is an environmentally friendly material because it is non-rusting, leaves no deposits, and has a long service life. Because of this advantage, stainless steel can be used well in a variety of sludge processes.

The characteristics in the aspect of ozone concentration selection are as follows: the municipal activated sludge treatment method of the invention adopts gas with ozone concentration not less than 80 percent to be mixed with the sludge according to the proportion, and because the ozone has strong oxidizing property, the method not only can kill most bacteria in the sludge, but also can destroy cell walls and cell membranes of microorganisms in the sludge, release a large amount of organic matters from the cells, kill organisms, realize the reduction of the sludge and kill harmful organisms in the sludge. Meanwhile, the solid catalyst is added when the ozone and the sludge are mixed, the solid catalyst accelerates the decomposition of the ozone to generate hydroxyl free radicals with stronger oxidizing capacity, the oxidation efficiency of the ozone is further improved, the cell wall breaking in the sludge is accelerated, the cell water in the cells is removed, and the subsequent solid-liquid separation is easier.

The characteristics in the aspect of reactor selection are as follows: the municipal activated sludge treatment system loads a plurality of catalyst bodies in a closed reactor, the catalyst bodies are scattered in the closed reactor in a free state, when the solid catalyst bodies and the mixture are subjected to mixing reaction in the reactor, the catalyst bodies are subjected to impact force of the mixture injected from the outside, and under the action of the impact force, the catalyst bodies and the mixture are continuously mixed and stirred in the reactor, and the mixture is fully contacted with the catalyst bodies. The maximum diameter of the discharge hole of the reactor is smaller than the minimum size of the catalyst body, the catalyst body cannot be discharged from the reactor together with the mixture, the use amount of the catalyst body is reduced, the use rate of the catalyst body is improved, and the surface layer of the catalyst body is made of rare precious metal materials, so that the sludge treatment cost is reduced. Because the treated sludge does not carry a catalyst, the treated sludge does not cause secondary pollution to the environment. The solid catalyst is stored in the closed reactor in a free scattering mode, the mixture entering the reactor can be fully contacted with the catalyst, the utilization rate of the catalyst is improved, the reaction time is shortened, and meanwhile, the mixture entering the reactor can be mixed with the catalyst again by violent collision, so that the complex process that stirring equipment needs to be additionally installed in the reactor in the traditional technology is simplified, the equipment volume is reduced, and the production cost is reduced. Because the ozone and the catalyst body fully react in the reactor, the utilization rate of the ozone in the reactor is as high as 95% -98%, the discharged sludge does not have any influence on people and livestock, and the safety of the sludge treatment system is improved.

The municipal activated sludge treatment method of the invention is characterized in that: the method has the advantages that the catalytic oxidation reaction is carried out at normal temperature and normal pressure, no medicament is added in the process, no toxicity is generated to the environment, organic matters in the sludge are retained, the filtered sewage has no adverse effect on the biochemical environment, the finally produced sludge with low moisture content can be used as an organic fertilizer and accords with the organic fertilizer standard issued by Ministry of agriculture, the municipal sludge is really recycled, and the method can be applied to the fields of agricultural production, landscaping, soil improvement and the like.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a process flow diagram of the municipal activated sludge treatment process of the invention;

FIG. 2 is a schematic diagram of the municipal activated sludge treatment system of the present invention;

FIG. 3 is a schematic diagram of a catalyst body structure of the tube structure of the present invention;

FIG. 4 is a schematic diagram of the structure of the catalyst body of the hollow sphere structure of the present invention.

1-a sludge pool, 2-a sludge pump, 3-a mixer, 4-an ozone generator, 5 a-a first reactor, 5 b-a second reactor, 5 c-a third reactor, 6-a catalyst, 61-a tube body, 62-a through hole and 63-a hollow sphere.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

Examples

Referring to fig. 3, the catalyst body 6 of the municipal activated sludge treatment catalyst body is made of stainless steel material as a carrier, and a metal layer, preferably, but not limited to, platinum oxide is supported on the surface of the stainless steel material, and noble metal oxides such as rhodium oxide, palladium oxide, iridium oxide, and the like may be used. Platinum is solidified on the surface of the stainless steel material by means of sintering or sputtering. The stainless steel material structure is preferably a circular tube body 61, a plurality of through holes 62 are formed in the tube wall of the tube body 61, the diameter of the tube body 61 is 30mm, the wall thickness of the tube body is 1.5mm, the length of the tube body is 25mm, and the diameter of each through hole is 5 mm. The diameter, wall thickness and length of the tubular body 61 are determined so that the catalyst body 6 can be continuously mixed and stirred with the catalyst body 6 in the reactor under the impact force of the mixture entering the reactor in the reactor.

Referring to fig. 4, the catalyst body 6 of the municipal activated sludge treatment catalyst body is made of stainless steel material as a carrier, and a metal layer, preferably, but not limited to, platinum oxide is supported on the surface of the stainless steel material, and noble metal oxides such as rhodium oxide, palladium oxide, iridium oxide, and the like may be used. Platinum is solidified on the surface of the stainless steel material by means of sintering or sputtering. The stainless steel material structure is preferably a hollow sphere 63, a plurality of through holes 62 are formed on the spherical surface of the hollow sphere 63, the diameter of the hollow sphere 63 is 40mm, the wall thickness of the sphere is 2mm, and the diameter of each through hole is 5 mm. The diameter and wall thickness of the hollow sphere 63 are determined so that the catalyst 6 can be continuously mixed with the catalyst 6 in the reactor by the impact force of the mixture introduced into the reactor.

The working principle is as follows: the catalytic body 6 adopts a stainless steel material as a carrier, and a noble metal oxide material is loaded on the surface of the stainless steel material in a high-temperature sintering or sputtering mode, so that the noble metal oxide material can form a compact layer on the surface of the stainless steel material in the high-temperature sintering or sputtering mode, the catalytic body 6 is not easy to wear, and the service life of the catalytic body is prolonged. The catalyst body 6 is of a hollow tube structure or a hollow sphere structure, and a plurality of through holes 62 are formed in the side wall of the tube body 61 and the spherical surface of the hollow sphere 63. The catalyst body 6 is made of a hollow tube body 61 and a hollow sphere 63, which are easy to process and manufacture, and the hollow tube body 61 may be formed by cutting a 304 stainless steel tube and then punching it, or may be formed by punching a 304 stainless steel plate and bending it into a circular tube body. The hollow sphere 63 may be formed by two semicircular hollow spheres with the same radius in a butt joint manner. The catalyst body 6 has low manufacturing cost and light weight, the contact areas among the catalyst bodies 6 and between the catalyst body 6 and the reactor are small, and the catalyst body 6 is not easy to deposit at the bottom of the reactor when in use and can be fully mixed with sludge in the reactor. The catalytic body 6 is provided with a plurality of through holes 62, so that a larger specific surface area can be obtained, the contact surface of sludge and the catalytic body 6 is increased, the reaction time is shortened, the self weight of the catalytic body 6 is further reduced, and the speed of the catalytic body 6 which is rolled in the reactor by a mixture and moves up and down back and forth is increased.

The catalyst body 6 uses a stainless steel material as a carrier, which has excellent corrosion resistance and wear resistance and is less susceptible to changes in pH and temperature than other metals. The stainless steel has very good physical and chemical stability. Because it is non-rusting, does not leave precipitates, and has long service life, and because of the advantage, the stainless steel can be well applied to various sludge treatments. The catalyst body 6 adopting the structure is not easy to be wound together with the substances in the mixture, and because the sludge contains a plurality of impurities which are not easy to degrade, such as hair, plastic bags, fabrics, sanitary paper towels, sticky substances, grass roots and the like, which are easy to be wound with other objects, the catalyst body 6 adopts a circular tube body structure and a hollow sphere body structure, has regular shape and smooth surface, can greatly reduce the probability of being wound with the substances, and avoids the catalyst body 6 from influencing the catalytic efficiency of the catalyst body and ozone after being wound. This catalyst body 6 produces collision and friction each other in the reactor, and mud is difficult to be attached to on catalyst body 6's surface, can not completely cut off the produced problem that slows down the decomposition of ozone of the combination of catalyst body 6 and ozone, also need not shut down and remove the attachment on catalyst body 6 surface, has reduced the equipment maintenance degree of difficulty.

Referring to fig. 2, the municipal activated sludge treatment system, which uses the catalyst 6 of the present invention to realize a continuous operation sludge treatment system, comprises a sewage pump 2, the sewage pump 2 is connected with the input port of a mixer 3 through a pipeline, the input port of the mixer 3 is provided with an air inlet pipeline for introducing ozone gas, the air inlet pipeline is connected with an ozone generator 4, the output port of the mixer 3 is connected with the top of a first reactor 5a of three communicated closed reactors through a pipeline, the reactors are communicated with each other in a way that the bottom of the first reactor 5a is communicated with the top of a second reactor 5b through a pipeline, the bottom of the second reactor 5b is communicated with the top of a third reactor 5c through a pipeline, the bottom of the third reactor 5c is connected with a subsequent treatment device through a pipeline, the first reactor 5a, The second reactor 5b and the third reactor 5c are each provided with a plurality of catalyst bodies 6 scattered therein, and the maximum pore diameter of the discharge holes of the first reactor 5a, the second reactor 5b and the third reactor 5c is smaller than the minimum size of the catalyst bodies. The volume ratio of the catalyst 6 to the reactors in the first reactor 5a, the second reactor 5b, and the third reactor 5c is 1: 10.

the working principle is as follows: the sludge pump 2 of the system conveys the residual sludge in the sludge pool 1 to the input port of the mixer 3 through a pipeline, an air inlet pipeline for introducing ozone gas is arranged at the input port of the mixer 3, the air inlet pipeline is connected with the ozone generator 4, negative pressure is generated on the inlet pipeline of the ozone gas when the mixer 3 generates sludge flow, and the ozone gas enters the mixer 3 through the air inlet pipeline to be mixed with the sludge. Ozone and water are subjected to primary reaction in sludge to decompose hydroxyl radicals, and the output port of the mixer 3 outputs a mixture of ozone gas, the hydroxyl radicals and the sludge. The mixer 3 conveys the mixture through a pipe into a closed first reactor 5 a. The communication mode between the reactors is that the bottom of the first reactor 5a is communicated with the top of the second reactor 5b through a pipeline, the bottom of the second reactor 5b is communicated with the top of the third reactor 5c through a pipeline, and the bottom of the third reactor 5c is connected with the subsequent treatment equipment through a pipeline. The three reactors are connected in such a way to realize continuous operation until the bacteria in the sludge are killed and the water in the microbial cells is completely released and then discharged.

According to the system, the catalyst 6 is added into the first closed reactor 5a, the second closed reactor 5b and the third closed reactor 5c, the catalyst 6 is scattered in the closed reactors in a free state, when the catalyst 6 and the mixture are mixed and reacted in the reactors, the catalyst 6 is impacted by the mixture injected from the outside, the catalyst 6 and the mixture are continuously mixed and stirred in the reactors under the action of the impact force, ozone in the mixture is fully contacted with the catalyst 6 to rapidly generate more hydroxyl radicals with stronger oxidizing capability, and the strong oxidizing capability of the hydroxyl radicals can kill bacteria in sludge in a short time and decompose cells of microorganisms, so that the sludge treatment time is greatly reduced, and the sludge treatment efficiency is improved. The maximum diameters of the three reactor discharge holes are smaller than the minimum size of the catalyst body, and the catalyst body 6 is not discharged from the reactor together with the mixture, thereby reducing the usage amount of the catalyst body 6 and improving the usage rate of the catalyst body 6. The surface layer of the catalyst body 6 is made of rare precious metal materials, so that the use cost of the catalyst body 6 is reduced. The treated sludge does not carry out the catalyst 6, so the treated sludge does not cause secondary pollution to the environment. The catalyst 6 is stored in the closed reactor in a free scattering mode, the mixture entering the reactor can be fully contacted with the catalyst 6, the utilization rate of the catalyst 6 is improved, the reaction time is shortened, and the mixture entering the reactor can be mixed with the catalyst 6 again by violent collision, so that the complex process that stirring equipment needs to be additionally installed in the reactor in the traditional technology is simplified, the equipment volume is reduced, and the production cost is reduced. Because the ozone and the catalyst body fully react in the reactor, the utilization rate of the ozone in the reactor is as high as 95% -98%, the discharged sludge does not have any influence on people and livestock, and the safety of the sludge treatment system is improved.

Referring to fig. 1 and 2, the municipal activated sludge treatment method of the present invention comprises the steps of:

step 1: pumping the residual sludge in the sludge pool 1 into a mixer 3 through a sewage pump 2, introducing ozone gas into the mixer 3 to be mixed with the sludge in a gas-liquid mode, forming hydroxyl radicals by combining the ozone with hydrogen bonds in water to form a mixture of the ozone, the hydroxyl radicals and the sludge, then injecting the mixture into a closed reactor, a plurality of catalyst bodies 6 are scattered in the reactor, the catalyst bodies 6 are impacted by the mixture when the mixture is injected into the reactor, under the action of impact force, the mixture and the catalyst 6 form a continuous mixing and stirring state in the reactor, the catalyst 6 accelerates ozone to form hydroxyl radicals, and the hydroxyl radicals and the ozone have oxidation reaction with microorganisms in the sludge, so that bacteria and oxidizing microorganisms are killed, microbial cell wall breaking and water release inside the microbial cells are promoted, and harmless and reduction treatment of the sludge is realized.

The specific manner of adding ozone to the mixer 3 is as follows: when gas with ozone concentration not lower than 80% is mixed with sludge according to the volume ratio of 10:0.1, the reaction time is about 3 minutes, and bacteria in the sludge are killed. When gas with the ozone concentration not lower than 80% is used and mixed with sludge according to the volume ratio of 10:1, the reaction time is about 3 minutes, the microorganisms in the sludge are decomposed, the cell wall breaking and the micelle opening are realized, and the water in the microorganism cells in the sludge is released. The principle is as follows: because ozone has strong oxidizability and high reaction speed, can react instantaneously in low concentration, has the sterilization capability which is hundreds times of that of chlorine, does not generate sludge and phenol odor, and has no secondary pollution. And the ozone disinfection efficiency is high, the ozone disinfection agent has strong killing capacity on various viruses and bacteria, and can also remove odor, decolor and improve water quality. Ozone belongs to a lytic agent, and can destroy or dissolve cell walls of microorganisms in sludge by utilizing ozone, quickly diffuse into cells, oxidize and destroy enzymes in the cells, and enable the cells to generate permeability distortion to cause the cells to be dissolved and dead. When gas with the ozone concentration not lower than 80% is used and is mixed with sludge according to the volume ratio of more than 10:4, the time is more than 4 hours, ozone can deeply react with microorganisms in the sludge to decompose a large amount of microorganisms into carbon dioxide and water, the total amount of the sludge can be reduced by 40% at most, the sludge is desertified, the purpose of sludge reduction can be achieved, but organic matters in the sludge disappear, so that the treated sludge is not beneficial to recycling.

The specific way of carrying out the catalytic oxidation reaction in the reactor is as follows: the catalyst body 6 is stored in the reactor, the catalyst body 6 is in full contact with the mixture, and the catalyst body 6 and the mixture can be combined with ozone in the mixture in the contact process to accelerate the ozone to form hydroxyl free radicals with stronger oxidizing capability, so that an ozone catalytic oxidation system of direct oxidation of the ozone and indirect oxidation of the hydroxyl free radicals is formed. Hydroxyl free radicals decompose difficultly-degradable macromolecular microorganisms, and due to the extremely strong oxidizability of the hydroxyl free radicals, a large amount of heat can be released in the oxidation reaction, the water temperature can be raised by the part of heat, a proper temperature environment is provided for the reaction of the macromolecular microorganisms waiting for oxidation, a continuous reaction is initiated, a circulating chain type effect is formed, and the macromolecular microorganisms are promoted to be more and more easily oxidized. For the degradation of the small-molecule microorganisms, the hydroxyl free radicals can indiscriminately carry out redox reaction with the easily degradable small-molecule microorganisms in the sludge to degrade the small-molecule microorganisms into carbon dioxide and water in a short time.

Step 2: conveying the sludge after catalytic oxidation to a membrane filter press for squeezing and dewatering, separating the sludge into a formed mud cake with the water content of about 60% and a filter pressing liquid by the membrane filter press, and feeding the separated filter pressing liquid into a sewage biochemical treatment system to achieve a solid-liquid separation state.

And step 3: the method comprises the steps of carrying out deep dehydration on a mud cake with the water content of about 60% to generate a mud cake with the water content of not more than 30%, carrying out deep dehydration by adopting saturated steam for heating and drying to form a mud cake with the water content of not more than 30%, cooling the used saturated steam through a condenser, enabling condensed water generated by the condenser to enter a sewage treatment system, and discharging waste gas generated by the condenser after the waste gas enters a waste gas treatment system for treatment.

And 4, step 4: and granulating the mud cakes with the water content of not more than 30% to form granular soil.

And 5: and granulating the mud cakes with the water content of not more than 30%, and fermenting to form the dried organic fertilizer.

In the scheme of the preferred embodiment, a flocculating agent with the weight ratio of 5 per mill is further included between the step 1 and the step 2, and the flocculating agent can enable solid suspended particles which are not easy to settle in sludge liquid to be coagulated and precipitated, so that the subsequent squeezing and dewatering are facilitated.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A municipal activated sludge treatment system is characterized in that,

the sludge treatment system comprises at least two closed reactors which are communicated, wherein a catalyst body is loaded in each reactor;

the delivery outlet of the mixer is connected with the top of any one of the at least two communicated closed reactors through a pipeline, and the communication mode among the reactors is as follows: the bottom of one reactor is communicated with the top of the other reactor through a pipeline, the bottom of the other reactor is connected with subsequent treatment equipment through a pipeline, and the maximum pore diameter of a discharge hole of the reactor is smaller than the minimum size of the catalyst body;

the catalyst body takes a stainless steel material as a carrier, a noble metal oxide layer is loaded on the surface of the stainless steel material, and the noble metal oxide is solidified on the surface of the stainless steel material in a sintering or sputtering mode;

the stainless steel material structure is any one of the following structures:

the pipe comprises a circular or polygonal pipe body, wherein the pipe wall of the pipe body is provided with a plurality of through holes;

the stainless steel material structure is a hollow sphere, and a plurality of through holes are formed in the spherical surface of the hollow sphere.

2. The municipal activated sludge treatment system according to claim 1, wherein the stainless steel material structure is a circular or polygonal pipe, the pipe wall of the pipe is provided with a plurality of through holes, the diameter of the pipe is 10mm to 50mm, the wall thickness of the pipe is 0.2mm to 3mm, the length of the pipe is 5mm to 50mm, and the diameter of the through holes is 1mm to 10 mm.

3. The municipal activated sludge treatment system according to claim 1, wherein the stainless steel material structure is a hollow sphere, a plurality of through holes are formed in the spherical surface of the hollow sphere, the diameter of the sphere is 10mm to 50mm, the wall thickness of the sphere is 0.2mm to 3mm, and the diameter of each through hole is 1mm to 10 mm.

4. The municipal activated sludge treatment system according to claim 1, wherein said precious metal oxide is any one or more of platinum oxide, rhodium oxide, palladium oxide, iridium oxide.

5. The municipal activated sludge treatment system according to claim 1, wherein the volume ratio of the catalyst in the reactor to any one of the reactors is 1-3: 10.

6. a municipal activated sludge treatment method based on the municipal activated sludge treatment system according to any one of claims 1 to 5, comprising the steps of:

7. The municipal activated sludge treatment method according to claim 6, wherein the step of adding ozone to the mixer to mix with the sludge in step 1 is specifically: and (3) mixing the gas with the ozone concentration not lower than 80% with the sludge according to the volume ratio of 10: 0.1-1, and mixing for 2-5 minutes in a mixer to kill bacteria in the sludge.

8. The municipal activated sludge treatment method according to claim 6, wherein the step of adding ozone to the mixer to mix with the sludge in step 1 is specifically: and (2) mixing gas with ozone concentration not lower than 80% with sludge according to the volume ratio of 10: 1-4, and mixing in a mixer for 2-5 minutes to oxidize microorganisms in the sludge, so that microbial cell wall breaking and micelle opening are realized, and water in microbial cells in the sludge is released.

9. The municipal activated sludge treatment method according to claim 6, wherein in step 2, the sludge is mechanically dewatered by: dewatering by adopting a membrane filter press, a plate-and-frame filter press or spiral compression equipment, and in the step 3, deeply dewatering the mud cake with the water content of 50% -70%: drying and dehydrating by adopting saturated steam.