Investigating industrial water-use efficiency in mainland China: An improved SBM-DEA model

Improving water-use efficiency (WUE) is a crucial way of achieving green industrial production and sustainable development. Applying an improved Super-slacks-based measure model with undesirable outputs, this paper investigates industrial WUE in mainland China. The results show that: (1) Industrial WUE in China is improving with the efficiency value increasing from 0.9874 to 0.9962 in 2012-2015. (2) The regions of water absolute scarcity and the vulnerability show the highest industry-related WUE, whereas the water stressed region, water scarce region, and water abundant region failed to achieve efficiency during the observation period. (3) The overall index value using the conventional model was higher than that of the improved model, indicating the need for a more reasonable water-use structure and environmentally friendly discharge structure. This study provides a new perspective for measuring industrial WUE and advances related studies by (1) incorporating the actual structure of water used and wastewater discharged with weights assigned to input and output slacks according to marginal use cost of water and marginal treatment cost of wastewater; and (2) adding realistic constraints on the amount of water used and wastewater discharged to the model. The estimated provinces in mainland China can adjust their industrial water-use structures and wastewater-discharge structures based on the results of this study, and thus improve the industrial WUE.