Carbon Emission Accounting and the Carbon Neutralization Model for a Typical Wastewater Treatment Plant in China
Chenxi Pang, Xi Luo, Bing Rong, Xuebiao Nie, Zhengyu Jin, Xue Xia
Abstract
To reduce carbon emissions and achieve carbon neutrality in China, it is pivotal to explore low-carbon wastewater treatment processes and carbon-neutral wastewater treatment plants (WWTPs). This study investigated the Beijing Gaobeidian WWTP to explore the current energy consumption and carbon emission status of representative WWTPs in China. Furthermore, it explored a possible low-carbon operating model. Results show that the current total energy consumption of Gaobeidian WWTP is 280,717 MWh/y, while its energy recovery is 268,788 MWh/y. As a result, the energy neutralization ratio is 95.8%, and the plant is close to reaching energy neutrality. The carbon emission of this plant is 446,468 t/y. However, it reduced its carbon emissions by 252,994 t/y and reached only 56.7% of carbon neutrality. Although the plant almost reached energy neutrality, it has a long way to go before reaching carbon neutrality. It was found that a subsequent increase in the recovery of residual heat from secondary effluent can increase the energy and carbon neutralization ratio to 523.1% and 219.0%, respectively, meaning that the WWTP can become a power production unit and a carbon sink. This study can provide a reference for exploring efficient energy use and reaching carbon neutrality for domestic WWTPs.