Life-Cycle Assessment (LCA) of Wastewater Treatment Plants: A Case Study of Tehran, Iran

Evaluating the environmental impacts of WWTPs and finding ways for wastewater reuse with minimum damage to our environment and human societies is a matter of vital importance. The objective of this study is to identify the critical sources of environmental impacts in Tehran's WWTP using life-cycle assessment (LCA) method. Eco-Indicator 99 is selected to perform life-cycle impact assessment (LCIA) using SimaPro 7.0 software. Results show that application of biogas instead of natural gas can make a significant contribution in alleviating the environmental effects of Tehran's WWTP (e.g., decreasing the negative impacts of fossil fuels about three times). Discharging the effluent into the surface water resources causes considerable damages to the quality of these resources and should be prevented. Instead, using the effluent for agricultural purposes in south of Tehran is a more eco-friendly practice especially from an eutrophication perspective (4% of the previous scenario). In general, the results obtained from implemented case study show that despite some shortcomings such as availability of sufficient and reliable data, LCA is an appropriate environmental system tool capable of streamlining the decision-making process in the wastewater treatment industry in Iran as well as fostering opportunities to achieve sustainability goals.