Research On Accounting Methodology Of Greenhouse Gas Emissions From Sewage Treatment Plants

With the excessive development of human social production activities,the concentration of greenhouse gases in the atmosphere is increasing,which is the main cause of global warming.In order to deal with this crisis,the researchers of various countries have carried out a series of studies on how to reduce the greenhouse gas emissions produced in the production and operation of various industries.As a major responsible country,China has declared the goal of "striving to achieve the peak of carbon dioxide emissions by 2030 and carbon neutrality by 2060",and has actively established and improved a greenhouse gas emission accounting system for all industries.As one of the controllable sources of man-made emissions,the sewage treatment industry has attracted wide attention.Its greenhouse gas emissions account for about 1%-2% of the total social greenhouse gas emissions.The accounting of the greenhouse gas emissions of sewage treatment plants is an important basic work to promote the low-carbon operation and development of the sewage treatment industry and even achieve the goal of carbon neutrality.Because of its economic level,process technology level and so on many reasons different sewage treatment plant and even the same sewage treatment plant in different time periods have different greenhouse gas emission characteristics.At present,there is a relative lack of monitoring,accounting and reportable methods for greenhouse gas emissions at different stages of greenhouse gas emission in sewage treatment plants in various accounting guidelines,which cannot provide good guidance for sewage treatment plants to study the differences of greenhouse gas emissions at different stages of greenhouse gas emission.The comparability of greenhouse gas emissions under different greenhouse gas emission scenarios is poor,which is not conducive to the lowcarbon operation planning of sewage treatment plants and the realization of the "dual carbon" goal.Based on this,this study carried out the greenhouse gas emission accounting methodology research of the sewage treatment plant.The main work and achievements of this study are as follows:(1)Divide the greenhouse gas emission situation of our sewage treatment plant.Analyse the situation of sewage treatment of Chinese sewage treatment plant,the situation of greenhouse gas emission and the situation of greenhouse gas emission.Discuss the importance of the situation of greenhouse gas emission produced in different sewage treatment plant and even in different time of the same sewage treatment plant in its sewage treatment operation process.Based on this,divide the greenhouse gas emission situation of Chinese sewage treatment plant.This study also discussed the greenhouse gas emission types that need to be calculated under different greenhouse gas emission scenarios of sewage treatment plants and the correlation between different greenhouse gas emission scenarios and the "two-carbon" construction goal.(2)The greenhouse gas emission accounting levels of sewage treatment plants are distinguished.It is proposed to divide the GHG emission accounting levels of sewage treatment plants,and the corresponding GHG emission accounting methods are divided into "GHG emission accounting method of the whole plant" and "GHG emission accounting method of the treatment unit",and the selection process of different GHG emission accounting levels is proposed.In order to achieve the purpose of monitoring,accounting and reporting of greenhouse gas emissions of sewage treatment plants,so as to be applicable to the accounting of greenhouse gas emissions under different greenhouse gas emission scenarios of sewage treatment plants.(3)The greenhouse gas emission calculation formula of sewage treatment plant is systematically given and the selection system of emission factors and activity data is established.The greenhouse gas emission accounting boundaries and accounting steps of sewage treatment plants under different greenhouse gas emission scenarios are defined,and the contents to be accounted for by sewage treatment plants or treatment units under different greenhouse gas emission scenarios are given,and the greenhouse gas offset caused by electricity and heat output of sewage treatment plants or treatment units is considered.The selection level of emission factor data and activity data of sewage treatment plant is determined,and the emission factor data is analyzed in detail,in order to make the accounting results of greenhouse gas emissions of sewage treatment plant more accurate,and promote the development of "localization" of greenhouse gas emission factor of sewage treatment plant.(4)Carried out the case analysis of greenhouse gas emission accounting methodology of sewage treatment plant."Whole-plant greenhouse gas emission Accounting Method" was used to calculate the greenhouse gas emissions caused by pollutant removal in A sewage treatment plant under the scenario of "carbon dioxide equivalent emission in sewage treatment to reach the standard",and the range of greenhouse gas emission factors under different pollutant removal conditions in A sewage treatment plant was calculated according to the corresponding accounting results.Methane and nitrous oxide emissions in the main sewage treatment unit of B regenerating water plant under the scenario of "near zero CO2 equivalent emission" and greenhouse gas emissions caused by power consumption in the sewage area were calculated by "greenhouse gas emission accounting Method of Treatment Unit".The methane and nitrous oxide emission factors of major sewage treatment units and the greenhouse gas emissions caused by tons of water and electricity consumption are summarized.