Incentive Mechanism for Allocating Wastewater Discharge Responsibility Based on Cooperative Game Theory

Clarifying responsibility for wastewater discharges and enhancing reasonable allocation of wastewater emission permits are critical for controlling wastewater discharge in the context global sustainable development plans. The traditional wastewater allocation approach has several drawbacks, such as sub-regional "free-riding," imbalanced regional development and demand, and unfair allocation mechanism. This study developed a model based on cooperative game theory to allocate responsibility for wastewater discharge in China's Tuojiang River Basin. In this model, the level of impact of a watershed sub-region on the water environment is determined, according to which the wastewater discharge responsibility is assigned. The stronger the impact of upstream sub-regions on downstream wastewater discharge, the greater the responsibility for wastewater discharge. Furthermore, by implementing the wastewater cooperation model, sub-regions can monitor and incentivize each other, through which wastewater discharges can be reduced by 16.38%, compared to the baseline mechanism and overall discharges can be reduced by 5007.99 tons. This study provides recommendations for appropriate management authorities to improve the allocation of wastewater discharge responsibility at the watershed scale.