Process for treating municipal pipe sediment sludge

Abstract

The application discloses a municipal pipeline deposited sludge treatment process, which comprises the following processes: (1) material separation; (2) sludge and sludge water treatment respectively; (3) sewage treatment in a sewage tank; and (4) deodorization process. The application is suitable for municipal pipeline deposited sludge treatment, can effectively reduce the content of organic matter in soil and the volume of a landfill, and has the advantages of physical and mechanical front-end treatment, addition of a small amount of medicament before sludge dewatering, less chemical medicament use, safety and environmental protection, low cost and no secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment technology, to the field of CO2F11 / 121, and more specifically to a process for treating sediment sludge deposited in municipal pipelines. Background Technology

[0002] With the increasing emphasis on environmental protection, my country has intensified its efforts in treating urban sewage and industrial wastewater. Municipal pipeline sludge refers to the sediment collected during the dredging and cleaning of drainage pipelines. The sediment in the pipelines includes particulate matter and impurities that enter the pipeline system with sewage and industrial wastewater, as well as road dust, garbage, and mud discharged from construction sites.

[0003] CN115231787A discloses a method and system for in-situ treatment of municipal sludge in landfills, including step 1, determining an oxidant, a solidifying agent, and a composite flocculant suitable for the sludge to be treated; step 2, oxidizing the sludge; step 3, mixing the sludge and solidifying agent evenly; step 4, mixing the sludge and composite flocculant evenly; and step 5, removing the supernatant above the sludge. The synergistic effect of oxidation, solidification, and sedimentation reduces the water content of the sludge, decreases its volume, and increases the landfill capacity. However, higher solids content means more reagent consumption, and the equipment requires frequent maintenance.

[0004] CN102814316A discloses a method for reducing the volume of sludge in a pipeline network, comprising the following steps: (1) pre-screening the sludge using a vibrating screen and a belt conveyor; (2) dewatering using a rotary drum screen and a screw press; (3) conveying the sludge to a sand-water separator via a sand pump for sand-water separation; and (4) fine filtration using a 1mm membrane screen and pressing the screenings using a screw press, which can effectively reduce environmental and soil pollution and reduce landfill volume. However, this method has problems such as a high organic content, making it unsuitable for direct use as building material.

[0005] Currently, the sludge treatment process for municipal pipelines typically employs a combination of front-end physical brushing and back-end chemical dewatering to break down the sludge into sand, sludge cake, and wastewater. However, because the sand contains organic matter, and the specific organic matter content and composition vary depending on the city's operating conditions, further processing is necessary based on these specific characteristics before the sand can be used as building material. Furthermore, existing technologies often result in sand and sludge cake with high organic matter content, making them unsuitable for direct use as building materials. Therefore, given the varying properties of municipal pipeline sludge, there is an urgent need to research and adjust new processes. Summary of the Invention

[0006] To address the aforementioned problems, this invention discloses a process for treating municipal pipeline sediment sludge, comprising the following steps:

[0007] (1) Material separation;

[0008] (2) Sludge and muddy water are treated separately;

[0009] (3) Wastewater treatment in the wastewater tank;

[0010] (4) Deodorization process.

[0011] In one embodiment, the material separation in step (1) specifically involves: the sludge to be treated is transported by a special transport vehicle to the sludge treatment station for unloading, first entering the material pool, and then separating large pieces of garbage and debris through a manual screen. Next, the sludge and muddy water in the material are treated separately.

[0012] Preferably, the average particle size of the large pieces of waste is >100mm. The separated large impurities are directly used for landfill.

[0013] In one embodiment, the sludge treatment in step (2) specifically involves: grabbing sludge from the material pool into the feeding system by a grab bucket, then passing it through a washing and separating machine for further impurity removal, and finally screening it into fine sand after passing through a mud-water separator, No. 1 sand-water separator, a scrubbing machine, No. 2 sand-water separator, a spiral chute, and a vibrating screen.

[0014] In one embodiment, the sludge is further cleaned by a washing and separating machine to remove impurities. The slag with an average particle size of 30mm-100mm, such as gravel, bricks, and leaves, is separated and directly used as landfill. The material with an average particle size of less than 30mm enters the mud-water separator.

[0015] In one embodiment, the particle size distribution of the raw material entering the mud-water separator is as follows, by percentage: 3mm-30mm 1.5-6.5%, 0.1mm-3mm 56%-81%, and the remainder is less than 0.1mm.

[0016] In one embodiment, the mud-water separator vibrates and separates slag with an average particle size of 3mm-30mm, while materials with an average particle size of less than 3mm are screened by the No. 1 sand-water separator.

[0017] In one embodiment, the sludge is screened in sand-water separator No. 1, the upper liquid enters the sewage tank, and the lower material 1 enters the scrubbing machine for processing before entering sand-water separator No. 2.

[0018] Preferably, the average particle size of the material in the lower layer 1 is 0.1 nm-3 mm.

[0019] In one embodiment, the impeller structure of the scrubbing machine is a curved blade open turbine type, and six layers of impellers are arranged on the mixing shaft, with the upper three layers rotating in opposite directions to the lower three layers of impellers.

[0020] The scrubbing machine primarily achieves material scrubbing and purification through the collision and friction between mineral particles. During equipment operation, the frequency and intensity of collisions and friction between mineral particles are increased to enhance the scrubbing effect. The urban pipeline sludge processed by this invention contains a large amount of organic matter, including leaves, human hair, animal hair, small pieces of plastic, oily clay, grease, etc. These organic materials are tightly entangled with the sludge. In existing technologies, the scrubbing machine is a folding blade turbine with four layers of impellers on the mixing shaft, and adjacent layers of impellers rotate in opposite directions. The material undergoes high-speed collisions and friction between the upper and lower impellers, resulting in high scrubbing intensity. During the sludge scrubbing process, the particle size is significantly reduced, with many particles smaller than 0.1 mm separating from the sludge system, reducing the amount of fine yarn obtained in the final product. The inventor, through the described structure of the scrubbing machine, ensures the removal of the aforementioned organic matter (after processing, the organic matter content is less than 5%) while maintaining the sludge particle size at 0.1 mm-3 mm, without causing a significant decrease in particle size. The inventor uses a curved-blade turbine impeller structure with six layers of impellers on the mixing shaft. The upper three layers rotate in opposite directions to the lower three layers. Other parts are the same as in the prior art. The six-layer impeller structure, with the upper three layers rotating in opposite directions to the lower three layers, is a conventionally understood technique in the art. This ensures that when the mixing device rotates, the upper impeller pushes the upper layer of material downwards, and the lower impeller pushes the lower layer of material upwards. In the middle section, the probability of collision and friction between larger-sized minerals is increased, maximizing the scrubbing effect of the mixing device and ensuring that fine particles do not experience excessive friction, thus reducing particle size. At the same time, municipal pipeline sludge contains a large amount of fragmented organic matter. Because it has a lower density than sludge, it is easily peeled off from the mineral surface through friction and impact, allowing it to stay in the scrubbing machine for a longer time. Under the collision with the sludge, the particle size will be further reduced, detaching it from the sludge system and reducing the organic matter in the sludge system. Furthermore, the use of a curved-blade turbine reduces power consumption compared to conventional flat-blade or folded-blade turbines.

[0021] In one embodiment, the No. 2 sand-water separator performs screening. The upper clear liquid enters the wastewater tank, and the lower material 2 enters the spiral chute for further removal of organic matter. The light organic matter on the outer edge of the spiral chute enters the circular vibrating screen for dewatering, and finally separates light impurities of 0.1-3mm, such as oil droplets and light clay. The material in the inner ring of the spiral enters the vibrating screen for screening, and finally separates fine sand of 0.1-3mm (organic matter content less than 3%).

[0022] In one embodiment, the mud and water treatment in step (2) specifically involves: the remaining mud and water in the feed tank is separated by a mechanical screen, the slag separated by the mechanical screen is directly used as landfill, and the mud and water in the tank is directly pumped to a mud and water separator for treatment.

[0023] In one embodiment, the sewage treatment in step (3) of the sewage tank is specifically as follows: the sewage is pumped to a thickener for concentration, the supernatant is directly discharged to the inlet pumping station of the municipal sewage treatment plant, and the underflow enters the conditioning tank. After a small amount of chemical treatment, the sludge in the conditioning tank reaches a solid content of 5%, and then enters the screw press for dewatering. The dewatered wet sludge (with a water content of about 80%) is incinerated together with other sludge from the municipal sewage treatment plant, and the sewage is collected again to the inlet pumping station of the municipal sewage treatment plant for further treatment.

[0024] In one embodiment, PAM reagent needs to be added to the thickener, and the amount of PAM reagent added is 0.05% to 0.25% of the wastewater mass by weight.

[0025] In one embodiment, PAM reagent needs to be added to the conditioning tank, and the amount of PAM reagent added is 0% to 0.05% of the wastewater mass by weight.

[0026] The dosage of the two additions does not exceed 0.3%, which greatly reduces the amount of chemical reagents used.

[0027] In one embodiment, the deodorization process in step (4) specifically involves treating the odor by means of local odor collection and using a biological deodorization method.

[0028] Preferably, the odor collection includes: a feed tank, a washing separator, a mud-water separator, a vibrating screen, a thickener, and a conditioning tank.

[0029] Beneficial effects

[0030] 1. The front-end separated sand has multiple grades and low organic matter content (which can be controlled below 3%). The fine sand can be directly used as a base filling material for road construction. The back-end sludge has a moisture content of about 80%, which reduces operating costs and facilitates subsequent incineration.

[0031] 2. Using a curved blade turbine reduces power consumption.

[0032] 3. The main shaft is equipped with six layers of impellers, and the upper three layers rotate in opposite directions to the lower three layers. While ensuring the removal of organic matter (after being treated by the scrubbing machine, the organic matter content is less than 5%), the sludge particle size is still maintained at 0.1mm-3mm, which will not cause a significant decrease in particle size.

[0033] 4. The front end uses physical and mechanical methods, while the back end adds a small amount of chemicals before sludge dewatering. The use of chemical agents is minimal, making it safe, environmentally friendly, low-cost, and free from secondary pollution. Attached Figure Description

[0034] Figure 1A schematic diagram showing six layers of impellers installed on the main shaft of a scrubbing machine, with the upper three layers rotating in opposite directions to the lower three layers. Detailed Implementation

[0035] Example 1

[0036] A process for treating sludge deposited in municipal pipelines, the process is as follows:

[0037] (1) Material separation: The sludge to be treated is transported to the sludge treatment station by a special transport vehicle and unloaded. It first enters the material pool and is separated from large pieces of garbage and debris by a manual screen. Then, the sludge and muddy water in the material are treated separately. The average particle size of the large pieces of garbage and debris is >100mm. The separated large impurities are directly used for landfill.

[0038] (2) Sludge and mud water are treated separately: The sludge in the material pool is grabbed by the grab bucket and fed into the feeding system. Then, after passing through the washing and separation machine, the slag with an average particle size of 30mm-100mm, such as gravel, bricks, leaves, etc., is separated and directly used as landfill. The material with an average particle size of less than 30mm enters the mud water separator.

[0039] The mud-water separator vibrates and separates slag with an average particle size of 3mm-30mm, while materials with an average particle size of less than 3mm are screened by the No. 1 sand-water separator.

[0040] The sludge is screened in the No. 1 sand-water separator. The upper liquid enters the sewage tank, and the lower material 1 enters the scrubbing machine for processing before entering the No. 2 sand-water separator.

[0041] The average particle size of the material in the lower layer 1 is 0.1 nm-3 mm.

[0042] The impeller structure of the scrubbing machine is a curved blade open turbine type, and six layers of impellers are set on the mixing shaft, with the upper three layers rotating in opposite directions to the lower three layers of impellers.

[0043] The No. 2 sand-water separator performs screening. The upper clear liquid enters the sewage tank, and the lower material 2 enters the spiral chute. The light organic matter on the outside of the spiral chute enters the circular vibrating screen for dewatering, and finally separates light impurities of 0.1-3mm, such as oil droplets and light clay. The material in the inner ring of the spiral enters the vibrating screen for screening, and finally separates fine sand of 0.1-3mm.

[0044] The mud and water treatment process is as follows: the remaining mud and water in the feed tank is separated by a mechanical screen. The slag separated by the mechanical screen is directly used as landfill, while the mud and water in the tank is directly pumped to a mud and water separator for treatment.

[0045] (3) Wastewater treatment in the wastewater tank: The wastewater is pumped to a thickener for concentration. The supernatant is discharged directly to the influent pumping station of the municipal wastewater treatment plant, while the underflow enters the conditioning tank. The sludge in the conditioning tank is conditioned with a small amount of chemicals to achieve a solids content of 5%, and then enters a screw press for dewatering. The dewatered wet sludge (with a moisture content of about 80%) is incinerated together with other sludge from the municipal wastewater treatment plant. The wastewater from this incineration is then collected and sent to the influent pumping station of the municipal wastewater treatment plant for further treatment.

[0046] PAM reagent needs to be added to the thickener. The amount of PAM reagent added is 0.2% of the wastewater mass by weight.

[0047] PAM reagent needs to be added to the conditioning tank. The amount of PAM reagent added is 0.05% of the mass of the wastewater.

[0048] (4) The deodorization process is as follows: deodorization is carried out by local odor collection, which includes: feed tank, washing separator, mud-water separator, vibrating screen, thickener, and conditioning tank.

[0049] Example 2

[0050] The difference between this embodiment and Embodiment 1 is that the impeller structure of the scrubbing machine is a folding blade turbine type, and four layers of impellers are set on the mixing shaft, with adjacent layers of impellers rotating in opposite directions.

[0051] Example 3

[0052] The difference between this embodiment and Embodiment 1 is that the impeller structure of the scrubbing machine is a folding blade open turbine type, and six layers of impellers are set on the mixing shaft, with the upper three layers rotating in opposite directions to the lower three layers of impellers.

[0053] Example 4

[0054] The difference between this embodiment and Embodiment 1 is that the impeller structure of the scrubbing machine is a curved blade open turbine type, and four layers of impellers are set on the mixing shaft, with adjacent two layers of impellers rotating in opposite directions.

[0055] Performance testing

[0056] The sludge raw material is sludge from different sections of the Zhangjiagang pipeline. The particle size distribution of the sludge raw material is shown in Tables 1 and 2 below.

[0057] Table 1 Sewage pipes of Zhangjiagang Linjiang Green Industrial Park

[0058] Particle size distribution (mm) solid weight (g) Particle size distribution % Cumulative distribution % Loss on ignition % 30 and above - - - - 3-30 5.8 3.3 3.3 - 0.1-3 102.3 58.26 61.56 28.46 0.1 or less 67.5 38.44 100 33.33

[0059] Table 2 Sewage Pipeline of Zhangjiagang Yangtze River Business Center

[0060] Particle size distribution (mm) solid weight (g) Particle size distribution % Cumulative distribution % Loss on ignition % 30 and above 87.4 20.25 20.25 3-30 96.7 22.40 42.65 0.1-3 182.6 42.30 84.94 3.25 0.1 or less 65.0 11.06 100 5.08

[0061] In a small-scale experiment, the processing capacity was 60 kg, and the processing time was 1 hour. Raw materials 1 and 2 were processed according to the processes in Examples 1-4. The mass of 0.1-3 mm fine sand and the loss on ignition rate were weighed. In the above processes, the loss on ignition rate was calculated after the material was dried, placed in a crucible, and fired in a muffle furnace at 600°C for 2 hours: Loss on ignition rate = (original mass - mass after firing) / original mass * 100%.

[0062]

[0063]

Claims

1. A process for treating sedimentary sludge from municipal pipelines, characterized in that, The process includes the following: (1) Material separation: (2) Sludge and muddy water are treated separately; The sludge treatment in step (2) is as follows: the sludge in the material pool is grabbed by the grab bucket and fed into the feeding system. Then, after passing through the washing and separation machine, the material is further removed and then enters the mud-water separator, No. 1 sand-water separator, scrubbing machine, No. 2 sand-water separator, spiral chute, and vibrating screen equipment in sequence to finally screen out fine sand of 0.1-3mm. The impeller structure of the scrubbing machine is a curved blade open turbine type, and six layers of impellers are set on the stirring main shaft, with the upper three layers rotating in opposite directions to the lower three layers of impellers. The No. 2 sand-water separator performs screening; the upper clear liquid enters the wastewater tank, and the lower material enters the spiral chute. (3) Wastewater treatment in the wastewater tank; (4) Deodorization process.

2. The process according to claim 1, characterized in that, The material separation in step (1) is as follows: the sludge to be treated is transported to the sludge treatment station for unloading. It first enters the material pool and is separated from large pieces of garbage and debris by a manual screen. Then, the sludge and mud water in the material are treated separately.

3. The process according to claim 2, characterized in that, The large pieces of waste have an average particle size of >100mm; the separated large impurities are directly used for landfill.

4. The process according to claim 1, characterized in that, The mud-water separator vibrates and separates slag with an average particle size of 3mm-30mm, while materials with an average particle size of less than 3mm are screened by the No. 1 sand-water separator.

5. The process according to claim 1, characterized in that, The specific steps of step (2) mud and water treatment are as follows: the remaining mud and water in the feed tank are separated by a mechanical screen, the slag separated by the mechanical screen is directly used as landfill, and the mud and water in the tank are directly pumped to the mud and water separator for treatment.

6. The process according to claim 1, characterized in that, The sewage treatment in step (3) of the sewage tank is specifically as follows: the sewage is pumped to the thickener, flocculation is carried out in the thickener, the supernatant of the thickener overflows to the inlet pumping station of the municipal sewage treatment plant, the underflow of the thickener enters the conditioning tank, and then is dewatered by the screw press. The dewatered wet sludge is incinerated together with other sludge from the municipal sewage treatment plant.

7. The process according to claim 1, characterized in that, The deodorization process in step (4) is specifically as follows: the deodorization is carried out by a biological deodorization method through local odor collection.

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