Holistic Wastewater Reuse Solutions – Evaluation of Treatment Efficiency, Environmental Impacts and Costs

The reuse of municipal wastewater is becoming a well-accepted solution for the management of water resources affecting various water-using sectors. Configuring the most sustainable and effective treatment system for the reuse of municipal wastewater, however, is still challenging. The present study offers an approach favoring the use of various sustainability metrics such as targeted or delivered treatment efficiency, environmental and economic impacts, area footprint and energy consumption for the configuration and selection of treatment systems for specific non-potable reuse applications and site characteristics. The results show that the presented approach can clearly provide information about trade-offs between performance, environmental impact and economic cost for different plant sizes and potential reuse demands. The provided real-case example, based on an extensive international study of various treatment systems, further illustrates that focusing on only one of the sustainability metrics may not provide the most sustainable solution. For some reuse applications, higher effluent quality than targeted will be provided at lower overall environmental impact and lower energy consumption but at higher costs. The study also demonstrates that the same treatment system may not be the most sustainable option for all plant sizes. The approach presented here provides a way to identify the most sustainable solution for each individual case, based on local requirements and plant size, through the holistic evaluation of treatment system sustainability.