Energy-pollutant nexus for wastewater treatment in China based on multi-regional input-output analysis

The heterogeneity of water and energy resource endowments and increasingly closer trade links among regions make it challenging to attain synergy in energy conservation and main pollutant reduction. This paper quantified the provincial energy intensity of COD removal in wastewater treatment plants (WWTPs), tracked the sectoral and regional water pollutant (COD) transfers beneath the provincial economic transactions based on the multi regional input-output analysis, and evaluated the energy saving and loss in different provinces based on an energy-pollutant nexus assessment framework. We found that economic trade could transfer local pollutant reduction pressure to distant regions through the national economic system. The critical VCOD importers (Beijing and Zhejiang) and exporters (Jiangxi and Heilongjiang) highlighted the necessity of emission reduction responsibility assignment from both the demand and the supply side. The VCOD was transferred from higher energy intensity provinces to lower energy intensity provinces, which contributed to a 1.42 x 10(8) kWh energy loss of COD removal nationally. Our results showed that from the energy-pollutant nexus perspective, some of the energy conservation and pollutant reduction goals were not always consistent. This study may help optimize the spatial regulation of national energy conservation and pollution reduction in a more integrated and systematic way.