Method for evaluating urban pipe network sludge resource utilization life cycle carbon footprint

Abstract

The invention discloses a method for evaluating a life cycle carbon footprint of urban pipe network sludge resource utilization. The method comprises the following steps: S1, determining a research purpose and a life cycle carbon footprint system boundary; s2, experimental data are collected, a life cycle list of two utilization scenarios of urban pipe network sludge recycling is constructed, and the two utilization scenarios comprise preparation of unfired ceramsite and preparation of water permeable bricks; s3, on the basis of openLCA software and an Ecoinvent3.8 background database, modeling is carried out on the two utilization scenes; s4, adopting a Recipe2016Midpoint v1.13 evaluation method to quantify the carbon footprints generated when one ton of dry sludge is treated by using the two kinds of scenes, and performing transverse comparison; s5, analyzing a carbon emission result, and searching a key emission process and a material flow according to the contribution degree; according to the method, two novel resource utilization situations of preparation of non-fired ceramsite and water permeable bricks from urban pipe network sludge are considered, and the influence of material and energy input factors on generated carbon footprints in the pipe network sludge treatment and utilization process is comprehensively evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon footprint, and in particular to a method for evaluating the carbon footprint of the life cycle of resource utilization of urban pipe network sludge. Background Art

[0002] Urban drainage pipe network is an important infrastructure to ensure the normal operation and development of the city, protect the environment and reduce the impact of urban disasters. Its function is to collect, transport, treat and discharge industrial wastewater, domestic sewage and rainwater. Pipeline sludge refers to the sediment removed during the maintenance of the drainage pipe network. If it is not removed in time, it may cause environmental problems such as sewage overflow and black and smelly river water. With the acceleration of the current urbanization process and the further expansion of urban scale, many cities are facing the problem of increasing pipe network sludge. Although the current commonly used sludge disposal methods such as incineration and landfill can handle a large amount of sludge in batches, they usually bring certain environmental damage and carbon emissions. Therefore, how to properly dispose of the increasing amount of urban pipe network sludge under the premise of low carbonization has become an issue that needs urgent attention.

[0003] The production of unfired ceramsite and permeable bricks from pipe network sludge is two new scenarios for the resource utilization of urban pipe network sludge. In theory, it not only absorbs and recycles solid wastes such as pipe network sludge, fly ash and engineering spoil, improves resource utilization and helps improve the urban environment; it can also be used to replace general building materials, reduce the carbon footprint generated by the production of building materials, and help the construction industry achieve carbon neutrality. Therefore, how to quantify the carbon footprint of the two new sludge resource utilization scenarios is of great significance for exploring their carbon emission reduction potential, reducing carbon emissions in the sludge treatment industry and building green cities.

[0004] In recent years, there have been some studies on the life cycle environmental impact assessment of various urban sludge disposal paths at home and abroad. However, most of these studies have not paid attention to the two new resource utilization paths of urban pipe network sludge to make unfired ceramsite and permeable bricks. They still use many traditional disposal paths as research objects, and there are problems such as unclear system boundaries and missing life cycle inventory data. It is difficult to make practical suggestions for the disposal and emission reduction and carbon reduction of urban pipe network sludge. Therefore, the use of life cycle assessment methods to quantitatively evaluate the two new sludge resource utilization scenarios is crucial to how to solve the issue of how to solve the increasing urban pipe network sludge production under the premise of low carbonization. Summary of the invention

[0005] To solve the above problems, the present invention proposes a carbon footprint assessment method for analyzing abalone farming systems, considering two new resource utilization scenarios of "unfired expanded clay" and "permeable bricks" prepared by urban pipeline sludge, and comprehensively evaluating the impact of material and energy input factors on the carbon footprint generated during the treatment and utilization of pipeline sludge.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for evaluating the carbon footprint of the life cycle of urban sewage sludge resource utilization, comprising the following steps:

[0008] S1. Determine the research purpose and the boundaries of the life cycle carbon footprint system;

[0009] S2. Collect experimental data and construct a life cycle inventory of two utilization scenarios of urban pipe network sludge resources, including the preparation of unfired ceramsite and the preparation of permeable bricks;

[0010] S3, modeling two utilization scenarios based on openLCA software and Ecoinvent3.8 background database;

[0011] S4. The Recipe2016 Midpoint v1.13 evaluation method was used to quantify the carbon footprint of treating one ton of dry sludge under two utilization scenarios and make a horizontal comparison;

[0012] The specific process of step S4 is as follows: The carbon footprint assessment of the resource utilization of urban pipe network sludge first analyzes the inventory data, collects the energy and material consumption of the two resource utilization scenarios, and then determines the emission factor. The carbon footprint calculation formula for the resource utilization of urban pipe network sludge is:

[0013]

[0014] Among them, CF i It represents the total carbon footprint generated by a certain scenario of sludge resource utilization in the pipeline network; D i represents the input data of the i-th energy or resource; F i represents the emission factor of the i-th energy or resource; i represents the various resources and energy invested in the two sludge resource utilization scenarios; n represents the total number of types of resources and energy invested;

[0015] The equipment used in the experiment is also included in the system boundary of the carbon footprint assessment. The calculation of the carbon footprint of the experimental equipment is amortized to the specific service life and annual processing volume of the equipment. The calculation formula for the carbon footprint of the experimental equipment is:

[0016] CF M =C M ÷(A L ×A C )

[0017] Among them, CF M represents the carbon footprint of a certain experimental equipment in the scenario of sludge resource utilization in the pipeline network; C M A represents the carbon footprint generated by the production and operation of the experimental equipment itself calculated based on the front-end data and emission factors;L Indicates the total service life of the equipment; A C It indicates the average amount of sludge that the equipment can process each year;

[0018] Based on the inventory data, life cycle assessment was conducted on two sludge resource utilization scenarios;

[0019] S5. Analyze the carbon emission results and find the key emission processes and material flows based on their contribution.

[0020] Preferably, the research purpose described in step S1 is to use the life cycle model to analyze the carbon emissions caused by energy and material inputs of two new scenarios of resource utilization of urban pipe network sludge; the functional unit is defined as the preparation of 1 ton of unfired expanded clay or permeable bricks; the life cycle carbon footprint system boundary includes all life cycle stages from the urban pipe network sludge being cleared out to the completion of final disposal; the sludge preparation scenario of unfired expanded clay includes three processes of sludge drying, raw material grinding and raw material mixing and stirring; the sludge preparation scenario of permeable bricks includes four processes of sludge drying, raw material grinding, pressing and sintering.

[0021] Preferably, the specific process of step S2 is: collecting experimental data of two sludge resource utilization scenarios for constructing a life cycle inventory, the experimental data including energy data, equipment input data and material input data; wherein the material input data refers to the data of chemicals and materials added during the sludge resource utilization process.

[0022] Preferably, in step S2,

[0023] The specific experimental steps for preparing unburned ceramsite from pipeline sludge are as follows: take sludge and engineering slag and put them into a drying oven at 60°C to dry to constant weight, and then grind them into powder using a vibration mill for 30 seconds; weigh 2.5g of sodium hydroxide particles and 35g of water glass, dissolve the sodium hydroxide particles in 3ml of water, then add them to the water glass, and cool to room temperature to make an alkali activator; weigh 20g of rainwater sludge, 50g of engineering slag, 30g of fly ash, and 20g of perlite, put them into a sludge mixer and stir for 30s, then add the alkali activator, and then put them into the sludge mixer and stir for 3min, during which about 25ml of water is added to the mixer intermittently; finally, divide the obtained ceramsite raw material into 5g and roll them into balls; cure at natural room temperature for 28 days, during which 5ml of water is sprayed for curing; after 28 days, the strength obtained is 5.51Mpa, the water absorption rate is 6.97% in 1h, and the bulk density is 885.49kg / m 3 Unburned ceramsite;

[0024] The specific experimental steps for preparing permeable bricks from pipe network sludge are as follows: grind the waste glass with a vibration mill for 30 seconds; take rainwater sludge, sewage sludge, and engineering slag and put them into a 60℃ drying oven to dry to constant weight, mix them according to the ratio of rainwater sludge: sewage sludge: engineering slag: waste glass = 2.5:2.5:4:1, and add expanded perlite with a mass ratio of 12%; then add 8% water by mass and put it into a mixer and stir for 2 minutes, then import it into a mold for pressing and molding; the molding pressure is 10MPa, and after demolding, put it into a 105℃ drying oven for 12 hours; after cooling to room temperature, put it into a muffle furnace for calcination, and the calcination conditions are: heating rate 5℃ / min, insulation at 1040℃ for 1h, and the strength of the brick is 12.8MPa and the permeability coefficient is 1.03×10 -2 cm / s permeable bricks.

[0025] Preferably, the specific process of step S3 is: importing the life cycle inventories of the two constructed pipeline sludge resource utilization scenarios into the openLCA software, selecting the flows with energy and resource input matching degrees greater than the threshold in the ecoinvent3.8 database according to the actual situation, and realizing the combination of foreground data and background data.

[0026] Preferably, the specific process of step S5 is: analyzing the carbon footprint life cycle assessment results of the two urban pipeline sludge resource utilization scenarios, evaluating the carbon footprint of the two sludge resource utilization scenarios, identifying the key influencing factors of the carbon footprint in each scenario, and then combining the current status of pipeline sludge treatment in the city, proposing targeted improvement suggestions, providing a feasible solution for low-carbon treatment of urban pipeline sludge, and reducing the carbon footprint of pipeline sludge treatment.

[0027] After adopting the above technical scheme, the present invention has the following beneficial effects: the present invention comprehensively analyzes the carbon footprint of the entire life cycle of urban pipeline sludge from cleaning out the pipeline to the final production of unfired expanded clay and permeable bricks, identifies the key contribution links to carbon emissions, and provides a scientific methodology for the carbon footprint accounting of the two resource utilization paths. It improves the comprehensiveness of the evaluation of urban pipeline sludge treatment and provides data support and scientific basis for achieving pollution reduction and carbon reduction in the urban pipeline sludge treatment industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the process of the present invention;

[0029] Figure 2 It is a schematic diagram of the boundary of the carbon footprint assessment system for two resource utilization scenarios of urban pipe network sludge of the present invention;

[0030] Figure 3 It is a schematic diagram of carbon footprint analysis of two scenarios of resource utilization of pipe network sludge from the process perspective of the present invention;

[0031] Figure 4 This is a schematic diagram of the carbon footprint analysis of two scenarios of pipeline sludge resource utilization from the perspective of energy consumption in the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] like Figures 1 to 4 As shown, a method for evaluating the carbon footprint of the life cycle of resource utilization of urban pipe network sludge includes the following steps:

[0034] S1. Determine the research purpose and the boundaries of the life cycle carbon footprint system;

[0035] The research purpose described in step S1 is to use the life cycle model to analyze the carbon emissions caused by energy and material inputs in two new scenarios of resource utilization of urban pipe network sludge; the functional unit is defined as the preparation of 1 ton of unfired ceramsite or permeable brick; the life cycle carbon footprint system boundary includes all life cycle stages from the removal of urban pipe network sludge to the completion of final disposal; the scenario of sludge preparation of unfired ceramsite includes three processes: sludge drying, raw material grinding and raw material mixing; the scenario of sludge preparation of permeable brick includes four processes: sludge drying, raw material grinding, pressing and sintering;

[0036] This embodiment takes the preparation of unfired expanded clay and permeable bricks from urban pipe network sludge as an example. The life cycle carbon footprint boundary includes the drying of sludge, grinding and mixing of raw materials, firing of final products, etc., and does not consider the maintenance of infrastructure and equipment.

[0037] S2. Collect experimental data and construct a life cycle inventory of two utilization scenarios of urban pipe network sludge resources, including the preparation of unfired ceramsite and the preparation of permeable bricks;

[0038] The specific process of step S2 is: collecting experimental data of two sludge resource utilization scenarios for constructing a life cycle inventory, the experimental data includes energy data, equipment input data and material input data; wherein the material input data refers to the data of chemicals and materials added in the process of sludge resource utilization;

[0039] This example takes the sludge removed from the rainwater and sewage pipe network in the Ailian River Basin in Longgang District, Shenzhen as the research object, and records in detail each link from pretreatment such as drying to the final product. Through the application of openLCA software, the production of 1 t of product (unfired expanded clay or permeable bricks) is taken as the research object, and the carbon footprint of two new types of pipe network sludge resource utilization scenarios is deeply analyzed.

[0040] In step S2, the specific experimental processes of the two resource utilization paths are as follows.

[0041] The specific experimental steps for preparing unburned ceramsite from pipeline sludge are as follows: take sludge and engineering slag and put them into a drying oven at 60°C to dry to constant weight, and then grind them into powder using a vibration mill for 30 seconds; weigh 2.5g of sodium hydroxide particles and 35g of water glass, dissolve the sodium hydroxide particles in 3ml of water, then add them to the water glass, and cool to room temperature to make an alkali activator; weigh 20g of rainwater sludge, 50g of engineering slag, 30g of fly ash, and 20g of perlite, put them into a sludge mixer and stir for 30s, then add the alkali activator, and then put them into the sludge mixer and stir for 3min, during which about 25ml of water is added to the mixer intermittently; finally, divide the obtained ceramsite raw material into 5g and roll them into balls; cure at natural room temperature for 28 days, during which 5ml of water is sprayed for curing; after 28 days, the strength obtained is 5.51Mpa, the water absorption rate is 6.97% in 1h, and the bulk density is 885.49kg / m 3 Unburned ceramsite;

[0042] The specific experimental steps for preparing permeable bricks from pipe network sludge are as follows: grind the waste glass with a vibration mill for 30 seconds; take rainwater sludge, sewage sludge, and engineering slag and put them into a 60℃ drying oven to dry to constant weight, mix them according to the ratio of rainwater sludge: sewage sludge: engineering slag: waste glass = 2.5:2.5:4:1, and add expanded perlite with a mass ratio of 12%; then add 8% water by mass and put it into a mixer and stir for 2 minutes, then import it into a mold for pressing and molding; the molding pressure is 10MPa, and after demolding, put it into a 105℃ drying oven for 12 hours; after cooling to room temperature, put it into a muffle furnace for calcination, and the calcination conditions are: heating rate 5℃ / min, insulation at 1040℃ for 1h, and the strength of the brick is 12.8MPa and the permeability coefficient is 1.03×10 -2 cm / s permeable bricks;

[0043] The life cycle inventory of unfired expanded clay and permeable bricks prepared from pipeline sludge is shown in Table 1.

[0044] Table 1: Life cycle inventory of unfired ceramsite and permeable bricks prepared from sewage sludge (per ton of product)

[0045]

[0046] After carbon footprint assessment, the results show that the carbon footprint of unfired ceramsite made from urban sewage sludge is basically the same as that of permeable bricks, among which material (including chemical) consumption is the main source of carbon emissions. The inputs of the entire system include water, auxiliary materials (sodium hydroxide, water glass, expanded perlite), infrastructure (electric drying blower, sludge mixer, vibration grinder, hydraulic press, tunnel kiln), and electricity. The front-end data comes from the experimental data of two scenarios of sewage sludge resource utilization, such as the input of electricity, materials and chemicals in the preparation process, and the back-end data such as the carbon emission factors of electricity, materials and chemicals come from the ecoinventv3.8 database;

[0047] S3, modeling two utilization scenarios based on openLCA software and Ecoinvent3.8 background database;

[0048] The specific process of step S3 is: import the life cycle inventories of the two pipeline sludge resource utilization scenarios that have been constructed into the openLCA software, select the flows with energy and resource input matching greater than the threshold in the ecoinvent3.8 database according to the actual situation, and realize the combination of foreground data and background data; among them, the foreground data refers to the process and operation data directly related to the product system, such as electricity and material input data; and the background data refers to the association process of energy and materials used in the system in standard databases such as ecoinvent.

[0049] S4. The Recipe2016 Midpointv1.13 evaluation method was used to quantify the carbon footprint of treating one ton of dry sludge under two utilization scenarios and make a horizontal comparison;

[0050] The specific process of step S4 is as follows: The carbon footprint assessment of the resource utilization of urban pipe network sludge first analyzes the inventory data, collects the energy and material consumption of the two resource utilization scenarios, and then determines the emission factor. The carbon footprint calculation formula for the resource utilization of urban pipe network sludge is:

[0051]

[0052] Among them, CF i It represents the total carbon footprint generated by a certain scenario of sludge resource utilization in the pipeline network; D i represents the input data of the i-th energy or resource; F i represents the emission factor of the i-th energy or resource; i represents the various resources and energy invested in the two sludge resource utilization scenarios; n represents the total number of types of resources and energy invested;

[0053] The equipment used in the experiment is also included in the system boundary of the carbon footprint assessment. The calculation of the carbon footprint of the experimental equipment is amortized to the specific service life and annual processing volume of the equipment. The calculation formula for the carbon footprint of the experimental equipment is:

[0054] CF M =C M ÷(A L ×A C )

[0055] Among them, CF M represents the carbon footprint of a certain experimental equipment in the scenario of sludge resource utilization in the pipeline network; C M A represents the carbon footprint generated by the production and operation of the experimental equipment itself calculated based on the front-end data and emission factors; L Indicates the total service life of the equipment; A C It indicates the average amount of sludge that the equipment can process each year;

[0056] Based on the inventory data, life cycle assessment was conducted on two sludge resource utilization scenarios;

[0057] S5. Analyze the carbon emission results and find the key emission processes and material flows based on their contribution;

[0058] The specific process of step S5 is: analyzing the carbon footprint life cycle assessment results of the two urban pipeline sludge resource utilization scenarios, evaluating the carbon footprint of the two sludge resource utilization scenarios, identifying the key influencing factors of the carbon footprint in each scenario, and then combining the current status of urban pipeline sludge treatment to put forward targeted improvement suggestions, provide a feasible solution for low-carbon treatment of urban pipeline sludge, and reduce the carbon footprint of pipeline sludge treatment.

[0059] The carbon footprint assessment results of the two scenarios of sewage sludge resource utilization are as follows: Figure 3 , 4As shown, the results show that for every ton of dry pipe network sludge processed, the production of unfired ceramsite (183.918kgCO2eq) is affected by different utilization scenarios, and the production of unfired ceramsite (183.918kgCO2eq) is higher than that of permeable bricks (176.2kgCO2eq). From the process point of view, the process that contributes the most to the carbon footprint of unfired ceramsite made from pipe network sludge is the addition of auxiliary materials (98.2%), and the process that contributes the most to the carbon footprint of permeable bricks is also the addition of auxiliary materials (61.0%); from the perspective of energy consumption, the largest contribution in the scene of unfired ceramsite made from pipe network sludge is the addition of auxiliary material sodium hydroxide (80.4%), followed by the addition of auxiliary material water glass (17.8%). Similarly, in the scenario of permeable bricks, the addition of auxiliary material expanded perlite is also the main source of contribution (61.0%), and the addition of chemicals occupies a major position in both resource utilization scenarios. However, compared with the production of unfired ceramsite, the scenario of permeable bricks requires more infrastructure equipment investment (23.1%).

[0060] This embodiment quantifies the life cycle carbon footprint of four disposal scenarios of pipeline sludge, identifies the key processes and material flows that affect the carbon footprint, and based on this, puts forward targeted improvement suggestions for the low-carbon disposal of urban pipeline sludge, which will help promote new resource utilization methods for pipeline sludge and provide a scientific basis for improving the sustainability of the sludge disposal industry.

[0061] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for evaluating the carbon footprint of the life cycle of urban sewage sludge resource utilization, characterized in that: The following steps are involved: S1. Determine the research purpose and the boundaries of the life cycle carbon footprint system; S2. Collect experimental data and construct a life cycle inventory of two utilization scenarios of urban pipe network sludge resources, including the preparation of unfired ceramsite and the preparation of permeable bricks; S3, modeling two utilization scenarios based on openLCA software and Ecoinvent3.8 background database; S4. The Recipe2016 Midpoint v1.13 evaluation method was used to quantify the carbon footprint of treating one ton of dry sludge under two utilization scenarios and make a horizontal comparison; The specific process of step S4 is as follows: The carbon footprint assessment of the resource utilization of urban pipe network sludge first analyzes the inventory data, collects the energy and material consumption of the two resource utilization scenarios, and then determines the emission factor. The carbon footprint calculation formula for the resource utilization of urban pipe network sludge is: Among them, CF i It represents the total carbon footprint generated by a certain scenario of sludge resource utilization in the pipeline network; D i represents the input data of the i-th energy or resource; F i represents the emission factor of the i-th energy or resource; i represents the various resources and energy invested in the two sludge resource utilization scenarios; n represents the total number of types of resources and energy invested; The equipment used in the experiment is also included in the system boundary of the carbon footprint assessment. The calculation of the carbon footprint of the experimental equipment is amortized to the specific service life and annual processing volume of the equipment. The calculation formula for the carbon footprint of the experimental equipment is: CF M =C M ÷(A L ×A C ) Among them, CF M represents the carbon footprint of a certain experimental equipment in the scenario of sludge resource utilization in the pipeline network; C M A represents the carbon footprint generated by the production and operation of the experimental equipment itself calculated based on the front-end data and emission factors; L Indicates the total service life of the equipment; A C It indicates the average amount of sludge that the equipment can process each year; Based on the inventory data, life cycle assessment was conducted on two sludge resource utilization scenarios; S5. Analyze the carbon emission results and find the key emission processes and material flows based on their contribution.

2. A method for evaluating the carbon footprint of the life cycle of urban pipe network sludge resource utilization as claimed in claim 1, characterized in that: The research purpose described in step S1 is to use the life cycle model to analyze the carbon emissions caused by energy and material inputs in two new scenarios of resource utilization of urban pipe network sludge; the functional unit is defined as the preparation of 1 ton of unfired expanded clay or permeable bricks; the life cycle carbon footprint system boundary includes all life cycle stages from the removal of urban pipe network sludge to the completion of final disposal; the sludge preparation of unfired expanded clay scenario includes three processes: sludge drying, raw material grinding and raw material mixing and stirring; the sludge preparation of permeable bricks scenario includes four processes: sludge drying, raw material grinding, pressing and sintering.

3. A method for evaluating the carbon footprint of the life cycle of urban pipe network sludge resource utilization as claimed in claim 1, characterized in that: The specific process of step S2 is: collecting experimental data of two sludge resource utilization scenarios for constructing a life cycle inventory, the experimental data including energy data, equipment input data and material input data; wherein the material input data refers to the data of chemicals and materials added during the sludge resource utilization process.

4. A method for evaluating the carbon footprint of the life cycle of urban pipe network sludge resource utilization as claimed in claim 1, characterized in that: In step S2, The specific experimental steps for preparing unburned ceramsite from pipeline sludge are as follows: take sludge and engineering slag and put them into a drying oven at 60°C to dry to constant weight, and then grind them into powder using a vibration mill for 30 seconds; weigh 2.5g of sodium hydroxide particles and 35g of water glass, dissolve the sodium hydroxide particles in 3ml of water, then add them to the water glass, and cool to room temperature to make an alkali activator; weigh 20g of rainwater sludge, 50g of engineering slag, 30g of fly ash, and 20g of perlite, put them into a sludge mixer and stir for 30s, then add the alkali activator, and then put them into the sludge mixer and stir for 3min, during which about 25ml of water is added to the mixer intermittently; finally, divide the obtained ceramsite raw material into 5g and roll them into balls; cure at natural room temperature for 28 days, during which 5ml of water is sprayed for curing; after 28 days, the strength obtained is 5.51Mpa, the water absorption rate is 6.97% in 1h, and the bulk density is 885.49kg / m 3 Unburned ceramsite; The specific experimental steps for preparing permeable bricks from pipe network sludge are as follows: grind the waste glass with a vibration mill for 30 seconds; take rainwater sludge, sewage sludge, and engineering slag and put them into a 60℃ drying oven to dry to constant weight, mix them according to the ratio of rainwater sludge: sewage sludge: engineering slag: waste glass = 2.5:2.5:4:1, and add expanded perlite with a mass ratio of 12%; then add 8% water by mass and put it into a mixer and stir for 2 minutes, then import it into a mold for pressing and molding; the molding pressure is 10MPa, and after demolding, put it into a 105℃ drying oven for 12 hours; after cooling to room temperature, put it into a muffle furnace for calcination, and the calcination conditions are: heating rate 5℃ / min, insulation at 1040℃ for 1h, and the strength of the brick is 12.8MPa and the permeability coefficient is 1.03×10 -2 cm / s permeable bricks.

5. A method for evaluating the carbon footprint of the life cycle of urban pipe network sludge resource utilization as claimed in claim 1, characterized in that: The specific process of step S3 is: import the life cycle inventory of the two pipeline sludge resource utilization scenarios that have been constructed into the openLCA software, select the flows with energy and resource input matching greater than the threshold in the ecoinvent3.8 database according to the actual situation, and realize the combination of foreground data and background data.

6. A method for evaluating the carbon footprint of the life cycle of urban pipe network sludge resource utilization as claimed in claim 1, characterized in that: The specific process of step S5 is: analyzing the carbon footprint life cycle assessment results of the two urban pipeline sludge resource utilization scenarios, evaluating the carbon footprint of the two sludge resource utilization scenarios, identifying the key influencing factors of the carbon footprint in each scenario, and then combining the current status of urban pipeline sludge treatment to put forward targeted improvement suggestions, provide a feasible solution for low-carbon treatment of urban pipeline sludge, and reduce the carbon footprint of pipeline sludge treatment.

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