Decoupling Relationship Between Economic Growth and Industrial Wastewater Discharges: A Case Study of Four Municipalities in China

The excessive discharges of industrial wastewater accompanying rapid industrialization has caused severe water pollution problems and ecological environment degradation, especially in China. Decoupling economic development from wastewater discharges generated from various industrial production activities is regarded as an important indicator for evaluating water efficiency of the industrial sector. This study makes an attempt to propose a decoupling method based on the Tapio decoupling model to analyze the relationship between economic growth and industrial wastewater discharges. Furthermore, from industrial and resource perspectives, the decoupling state is decomposed from four aspects, namely, technology, structure, ecology and efficiency. And the leading factors of decoupling are obtained based on the decomposition results. The following three main results are found. (1) The ordering of decoupling levels observed in the four municipalities are as follows: Chongqing > Shanghai > Tianjin > Beijing (2008–2017). (2) The decoupling relation between economic growth and industrial wastewater discharges mainly shows two states: strong decoupling and weak decoupling. (3) The decomposition results show that the technology and efficiency effects are the main two drivers of decoupling relationship between economic growth and industrial wastewater discharges. Overall, the decoupling and decomposition results can help decision makers formulate tailor-made policy instruments at municipal level to achieve coordinated development of economic growth and water environment protection so as to support their sustainable development mission.