A method for evaluating the life cycle carbon footprint of urban sewage sludge resource utilization

Abstract

The present invention discloses a method for evaluating the life cycle carbon footprint of resource utilization of urban pipeline sludge, comprising the following steps: S1, determining a research purpose and a life cycle carbon footprint system boundary; S2, collecting experimental data, and constructing a life cycle inventory of two utilization scenarios of urban pipeline sludge resource utilization, the two utilization scenarios including preparing unfired ceramsite and preparing permeable bricks; S3, modeling the two utilization scenarios based on openLCA software and Ecoinvent3.8 background database; S4, using the Recipe2016Midpoint v1.13 evaluation method to quantify the carbon footprint of treating one ton of dry sludge in the two utilization scenarios and conduct a horizontal comparison; S5, analyzing the carbon emission results, and finding key emission processes and material flows based on their contribution; the method considers two new resource utilization scenarios of preparing "unfired ceramsite" and "permeable bricks" from urban pipeline sludge, and comprehensively evaluates the impact of material and energy input factors on the generated carbon footprint during the treatment and utilization of pipeline sludge.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon footprint technology, 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 networks are crucial infrastructure for ensuring the normal operation and development of cities, protecting the environment, and mitigating the impact of urban disasters. Their functions include collecting, transporting, treating, and discharging industrial wastewater, domestic sewage, and rainwater. Pipeline sludge refers to the sediment removed during drainage network maintenance. If not promptly removed, it can lead to environmental problems such as sewage overflows and the blackening and odorous appearance of river water. With the acceleration of urbanization and the continued expansion of urban areas, many cities are facing the challenge of increasing amounts of pipeline sludge. While currently common sludge disposal methods, such as incineration and landfilling, can handle large quantities of sludge in batches, they often result in significant environmental damage and carbon emissions. Therefore, how to properly dispose of this increasing amount of urban pipeline sludge while maintaining a low-carbon approach has become a pressing issue.

[0003] The production of unfired ceramsite and permeable bricks from sewage sludge represents two new approaches to resource utilization in urban sewage sludge. In theory, these approaches not only absorb and recycle sewage sludge, fly ash, and construction spoil, improving resource utilization and the urban environment, but also can be used to replace conventional building materials, reducing the carbon footprint of their production and contributing to carbon neutrality in the construction industry. Therefore, quantifying the carbon footprint of these two new sewage sludge resource utilization scenarios is crucial for exploring their potential for carbon reduction, contributing to carbon reduction in the sewage sludge treatment industry, and building green cities.

[0004] In recent years, there has been considerable research both domestically and internationally on the life cycle environmental impact assessment of various municipal sewage sludge disposal pathways. However, most of these studies have failed to address the two new resource-based utilization pathways for urban sewage sludge: the production of unfired ceramsite and permeable bricks. Instead, they have focused on numerous traditional disposal pathways, and these studies suffer from issues such as unclear system boundaries and missing life cycle inventory data, making it difficult to provide concrete recommendations for the disposal and emission and carbon reduction of urban sewage sludge. Therefore, employing a life cycle assessment approach to quantitatively evaluate these two new sludge resource utilization scenarios is crucial for addressing the increasing production of sewage sludge from urban sewage networks while maintaining a low-carbon approach. Summary of the Invention

[0005] To address the above issues, the present invention proposes a carbon footprint assessment method for analyzing abalone farming systems. Taking into account two new resource utilization scenarios, namely, the preparation of "unfired expanded clay" and "permeable bricks" from urban pipe network sludge, the method comprehensively evaluates the impact of material and energy input factors on the carbon footprint generated during the treatment and utilization of pipe network 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 resource utilization of urban sewage sludge comprises the following steps:

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

[0009] S2. Collect experimental data and construct a life cycle inventory for two utilization scenarios of urban sewage sludge, including the production of unfired ceramsite and the production 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 conduct a horizontal comparison.

[0012] The specific process of step S4 is as follows: The carbon footprint assessment of 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 resource utilization of urban pipe network sludge is:

[0013]

[0014] Among them, CF i Indicates the total carbon footprint generated by a certain scenario of sludge resource utilization in a 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 input in the two sludge resource utilization scenarios; n represents the total number of resource and energy types input;

[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 evenly distributed to the specific service life and annual processing volume of the equipment. The calculation formula of 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 front-end data and emission factors;L Indicates the total service life of the equipment; A C Indicates the average amount of sludge that the equipment can process each year;

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

[0019] S5. Analyze carbon emission results and identify 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 pipeline 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 pipeline sludge to the completion of final disposal; the sludge preparation scenario of unfired expanded clay includes three processes: sludge drying, raw material grinding and raw material mixing and stirring; the sludge preparation scenario of permeable bricks includes four processes: 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 waste soil and put them into a drying oven at 60°C to dry to constant weight, and then grind them into powder with a vibration mill for 30s; weigh 2.5g of sodium hydroxide particles and 35g of water glass, dissolve the sodium hydroxide particles with 3ml of water, then add them to the water glass, and cool to room temperature to prepare an alkaline activator; weigh 20g of rainwater sludge, 50g of engineering waste soil, 30g of fly ash, and 20g of perlite, put them into a sludge mixer and stir for 30s, then add the alkaline 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 waste glass with a vibration mill for 30 seconds; take rainwater sludge, sewage sludge, and engineering debris 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 debris: 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 blender and stir for 2 minutes, then introduce it into a mold for pressing and forming; the molding pressure is 10MPa, and after demoulding, put it into a 105℃ drying oven and dry it for 12 hours; after cooling to room temperature, put it into a muffle furnace for calcination. The calcination conditions are: heating rate 5℃ / min, holding at 1040℃ for 1 hour, and the obtained strength 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 pipeline sludge resource utilization scenarios that have been constructed into the openLCA software, selecting flows with energy and resource input matching degrees greater than a threshold in the ecoinvent3.8 database according to actual conditions, 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 footprints 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.

[0027] After adopting the above technical solution, 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, thereby improving the comprehensiveness of the urban pipeline sludge treatment assessment, and providing data support and scientific basis for achieving pollution reduction and carbon reduction development 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 Schematic diagram of the carbon footprint assessment system boundary for two resource utilization scenarios of urban pipe network sludge according to the present invention;

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

[0031] Figure 4 Schematic diagram of 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 solutions 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 intended 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 sewage sludge includes the following steps:

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

[0035] The research objective described in step S1 is to use a life cycle model to analyze the carbon emissions caused by energy and material inputs in two new scenarios for resource utilization of urban pipe network sludge; the functional unit is defined as the production 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 sludge production of unfired ceramsite scenario includes three processes: sludge drying, raw material grinding, and raw material mixing; the sludge production of permeable brick scenario includes four processes: sludge drying, raw material grinding, pressing, and sintering;

[0036] This example uses the production of unfired expanded clay and permeable bricks from urban sewage sludge as an example. The life cycle carbon footprint boundary includes the drying of the sludge, the grinding and mixing of the raw materials, and the firing of the final product, but does not consider infrastructure and equipment maintenance.

[0037] S2. Collect experimental data and construct a life cycle inventory for two utilization scenarios of urban sewage sludge, including the production of unfired ceramsite and the production of permeable bricks.

[0038] The specific process of step S2 is as follows: 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; the material input data refers to the data of chemicals and materials added during the sludge resource utilization process;

[0039] This example uses sludge removed from the rainwater and sewage pipelines in the Ailian River basin in Longgang District, Shenzhen, as the research object. Detailed records are kept of every step from pretreatment such as drying to final product production. Using openLCA software, an in-depth analysis of the carbon footprint of two novel pipeline sludge resource utilization scenarios is conducted, using the production of 1 ton of product (unfired expanded clay or permeable bricks) as the research object.

[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 waste soil and put them into a drying oven at 60°C to dry to constant weight, and then grind them into powder with a vibration mill for 30s; weigh 2.5g of sodium hydroxide particles and 35g of water glass, dissolve the sodium hydroxide particles with 3ml of water, then add them to the water glass, and cool to room temperature to prepare an alkaline activator; weigh 20g of rainwater sludge, 50g of engineering waste soil, 30g of fly ash, and 20g of perlite, put them into a sludge mixer and stir for 30s, then add the alkaline 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 waste glass with a vibration mill for 30 seconds; take rainwater sludge, sewage sludge, and engineering debris 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 debris: 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 blender and stir for 2 minutes, then introduce it into a mold for pressing and forming; the molding pressure is 10MPa, and after demoulding, put it into a 105℃ drying oven and dry it for 12 hours; after cooling to room temperature, put it into a muffle furnace for calcination. The calcination conditions are: heating rate 5℃ / min, holding at 1040℃ for 1 hour, and the obtained strength is 12.8MPa and the permeability coefficient is 1.03×10 -2 cm / s permeable bricks;

[0043] The life cycle inventory of unfired ceramsite 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] A carbon footprint assessment revealed that the carbon footprint of producing unfired ceramsite from urban sewage sludge is roughly comparable to that of producing permeable bricks, with material (including chemical) consumption being the primary source of carbon emissions. Inputs to the system include water, auxiliary materials (sodium hydroxide, water glass, expanded perlite), infrastructure (electric drying blowers, sludge mixers, vibrating grinders, hydraulic presses, tunnel kilns), and electricity. Front-end data was derived from experimental data from two sewage sludge resource utilization scenarios, including the inputs of electricity, materials, and chemicals during the preparation process. Back-end data, such as carbon emission factors for electricity, materials, and chemicals, was obtained from the ecoinvent v3.8 database.

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

[0048] The specific process of step S3 is as follows: the life cycle inventories of the two pipeline sludge resource utilization scenarios that have been constructed are imported into the openLCA software. Based on the actual situation, flows with energy and resource input matching greater than the threshold are selected from the ecoinvent3.8 database to realize the combination of foreground data and background data. Among them, foreground data refers to process and operation data directly related to the product system, such as power and material input data; while background data refers to the associated processes 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 conduct a horizontal comparison.

[0050] The specific process of step S4 is as follows: The carbon footprint assessment of 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 resource utilization of urban pipe network sludge is:

[0051]

[0052] Among them, CF i Indicates the total carbon footprint generated by a certain scenario of sludge resource utilization in a 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 input in the two sludge resource utilization scenarios; n represents the total number of resource and energy types input;

[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 evenly distributed to the specific service life and annual processing volume of the equipment. The calculation formula of 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 front-end data and emission factors; L Indicates the total service life of the equipment; A C Indicates the average amount of sludge that the equipment can process each year;

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

[0057] S5. Analyze carbon emission results and identify 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 pipeline sludge resource utilization scenarios are as follows: Figure 3 、 4As shown in the results, for every ton of dried pipe network sludge processed, the carbon footprint of unfired ceramsite (183.918 kg CO₂eq) is higher in the production of unfired ceramsite (176.2 kg CO₂eq) than in the production of permeable bricks (183.918 kg CO₂eq). From a process perspective, the largest contribution to the carbon footprint of unfired ceramsite from pipe network sludge is the addition of auxiliary materials (98.2%), and the largest contribution to the carbon footprint of permeable brick production is also the addition of auxiliary materials (61.0%). From an energy consumption perspective, the largest contribution in the unfired ceramsite production scenario is the addition of the auxiliary material sodium hydroxide (80.4%), followed by the addition of the auxiliary material water glass (17.8%). Similarly, in the permeable brick production scenario, the addition of the auxiliary material expanded perlite is also the main source of contribution (61.0%). The addition of chemicals occupies a major position in both resource utilization scenarios. However, compared to the production of unfired ceramsite, the permeable brick production scenario requires more infrastructure and equipment investment (23.1%).

[0060] This example quantifies the lifecycle carbon footprint of four disposal scenarios for pipeline sludge, identifies key processes and material flows that affect the carbon footprint, and based on this, proposes targeted improvement suggestions for the low-carbon disposal of urban pipeline sludge. This 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 description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection 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 objectives and the boundaries of the life cycle carbon footprint system; S2. Collect experimental data and construct a life cycle inventory for two utilization scenarios of urban sewage sludge, including the production of unfired ceramsite and the production 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 conduct a horizontal comparison. The specific process of step S4 is as follows: The carbon footprint assessment of 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 resource utilization of urban pipe network sludge is: Among them, CF i Indicates the total carbon footprint generated by a certain scenario of sludge resource utilization in a 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 input in the two sludge resource utilization scenarios; n represents the total number of resource and energy types input; 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 evenly distributed to the specific service life and annual processing volume of the equipment. The calculation formula of 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 front-end data and emission factors; L Indicates the total service life of the equipment; A C Indicates the average amount of sludge that the equipment can process each year; Based on the inventory data, a life cycle assessment was conducted on two sludge resource utilization scenarios; S5. Analyze carbon emission results and identify key emission processes and material flows based on their contribution.

2. The method for evaluating the life cycle carbon footprint of urban sewage sludge resource utilization according to 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 pipeline 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 pipeline sludge to the completion of final disposal; the scenario of sludge preparation of unfired expanded clay includes three processes: sludge drying, raw material grinding and raw material mixing and stirring; the scenario of sludge preparation of permeable bricks includes four processes: sludge drying, raw material grinding, pressing and sintering.

3. The method for evaluating the carbon footprint of the life cycle of resource utilization of urban pipe network sludge according to 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 includes energy data, equipment input data and material input data; among them, material input data refers to the data of chemicals and materials added during the sludge resource utilization process.

4. The method for evaluating the carbon footprint of the life cycle of resource utilization of urban pipe network sludge according to 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 waste soil and put them into a drying oven at 60°C to dry to constant weight, and then grind them into powder with a vibration mill for 30s; weigh 2.5g of sodium hydroxide particles and 35g of water glass, dissolve the sodium hydroxide particles with 3ml of water, then add them to the water glass, and cool to room temperature to prepare an alkaline activator; weigh 20g of rainwater sludge, 50g of engineering waste soil, 30g of fly ash, and 20g of perlite, put them into a sludge mixer and stir for 30s, then add the alkaline 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 Unfired ceramsite; The specific experimental steps for preparing permeable bricks from pipe network sludge are as follows: grind waste glass with a vibration mill for 30 seconds; take rainwater sludge, sewage sludge, and engineering debris 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 debris: 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 blender and stir for 2 minutes, then introduce it into a mold for pressing and forming; the molding pressure is 10MPa, and after demoulding, put it into a 105℃ drying oven and dry it for 12 hours; after cooling to room temperature, put it into a muffle furnace for calcination. The calcination conditions are: heating rate 5℃ / min, holding at 1040℃ for 1 hour, and the obtained strength is 12.8MPa and the permeability coefficient is 1.03×10 -2 cm / s permeable bricks.

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

6. The method for evaluating the carbon footprint of the life cycle of resource utilization of urban pipe network sludge according to 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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