Volume 46: Energy Transitions toward Carbon Neutrality: Part IX

Accounting of Greenhouse Gas Emissions from Wastewater Infrastructures on the Qinghai-Tibet Plateau Yao Huang, Delin Fang, Saige Wang, Bin Chen

Abstract

The wastewater sector represents a significant contributor to greenhouse gas (GHG) emissions, and the issue of GHG emissions from wastewater infrastructures in the Qinghai-Tibet Plateau (QTP) has been overlooked. This study constructed a unified accounting framework based on the emission factors approach to quantify GHG emissions from wastewater infrastructures on the QTP, and identified the influencing factors of GHG emissions changes through Logarithmic Mean Divisia Index (LMDI). Within our accounting framework, we took into account the temperature coefficient to accurately represent the low water temperatures prevalent on the QTP. Furthermore, we revised the emission factor for electricity consumption by considering the local energy structure based on the development of clean energy. Spatial and temporal differences were analyzed using the GHG emissions accounting results spanning from 2014 to 2018. The results show that total GHG emissions from QTP’s wastewater infrastructures increased from 0.25 Mt CO2e to 0.43 Mt CO2e between 2014 and 2018, with the cities along the edge in the east exhibiting noticeably higher GHG emissions. The development of clean energy on the QTP has led to a reduction in the electricity emission factor, thereby slowing down the growth of GHG emissions by 18.7%. The increase in sludge yield and electricity intensity of WWTPs contributed 10.3% and 9.6% to the overall growth of GHG emissions, and reducing these two influencing factors can effectively decelerate the upward trajectory of GHG emissions in the wastewater sector.

Keywords Wastewater treatment, greenhouse gas emissions, clean energy, influencing factors, Qinghai-Tibet Plateau