Carbon footprint analysis of advanced biological wastewater treatment plant

This study presents the carbon footprint assessment of an advanced biological wastewater treatment plant. The greenhouse gas (GHG) emission sources of the plant have been identified and the processes from which these emissions originate have been determined. In the carbon footprint assessment, direct and indirect emissions were considered by utilizing the United Nations Framework on Climate (UNFCC), Intergovernmental Panel on Climate Change (IPCC) methodology and National Greenhouse Accounts Factors. The total GHG emission amount of the plant is estimated as 10,389 and 53,529 tCO2eq for 2018 and 2019, respectively. In 2019, the carbon footprint increased by approximately 5 times compared to 2018 due to poor operation of the plant. The largest share in total GHG emissions belongs to direct emissions. On the other hand, the main source of direct emissions is methane emissions from anaerobic stabilization ponds. Emissions from the electricity consumption were identified as the main source of indirect emissions. The present study is a preliminary study for taking measures to reduce GHG emissions by evaluating the carbon footprint by determining the source and amount of GHG emissions of the plant. Operating conditions of each processes is crucial in analyzing the carbon footprint of different treatment configurations. GHG emissions of the plant can be reduced by operational improvements such as increasing the amount and efficiency of biogas and reducing the consumption of chemicals. In addition, the use of clean energy sources such as wind, solar and biomass energy can increase energy efficiency and reduce GHG emissions of the plant.