[Carbon Emission Analysis and Carbon Reduction Strategy of Small and Medium-scale Municipal Wastewater Treatment Plants in Cities and Towns].

The carbon emissions of three typical processes （AAO, MSBR, and oxidation ditch） were systematically analyzed from the perspective of the whole wastewater treatment process based on the annual data of eleven urban small and medium-scale WWTPs in the year 2022, and the effects of different influent characteristics （TP, TN, BOD, COD, influent volume, and COD/TN） on the carbon emissions were studied by using the partial least squares structural equation modeling （PLS-SEM） method. The results showed that indirect carbon emissions dominated the total carbon emissions of small and medium-scale WWTPs （69.5%）, and carbon emissions from electricity consumption were the largest source （43.