Selection of sustainable municipal water reuse applications by multi-stakeholders using game theory.

Globally the trend of water reuse has been increasing. The public perception and government regulations are supportive for reclaimed water use in Canada. Reclaimed water can be used in variety of applications that may have different performance in economic, environmental and social dimensions for various stakeholders, indicating decision on water reuse selection is complex. This research proposes a multi-criteria multi-decision-makers framework combining multicriteria decision analysis (MCDA) and game theory for a selection of a sustainable water reuse application. The proposed framework is applied to the City of Penticton, BC, Canada. The evaluation criteria included were environmental: fresh water saving, energy use, and carbon emissions; economic: annualized life cycle cost; and social: government policy, public perception, and human health risk for three stakeholders: municipality, citizens, and farm operators. The game theory is applied to eight water reuse options considering a cooperative game. The result shows that lawn, golf course and public park irrigation and toilet flushing with an equal sharing of municipal benefits between the municipality and citizens is the optimal solution. By using the solution, the municipality can have an additional saving of approximately $35/household/year and the citizens have to spend an additional amount of approximately $100/household/year for dual plumbing of toilet and lawn for reclaimed water use. The additional expenditure for the citizens is within Canada's public willingness to pay an additional charge for reclaimed water use. The scenario analysis shows that the weights of sustainability criteria are important in decision-making. Also, the sensitivity analysis shows that the change in the amount of reclaimed water availability can affect water reuse sustainability performance. The proposed framework can also be used in other applications by changing the number of evaluation criteria and stakeholders as required.