Connection of neighboring wastewater treatment plants: economic and environmental assessment

• Integrated management of neighboring wastewater treatment plants was assessed.
• Environmental and economic aspects were considered.
• Environmental impacts were minimized with the integrated operation.
• The investment to connect the two wastewater treatment plants was viable.

This paper explores the potential of integrated management of neighboring wastewater treatment plants (WWTPs). The novelty lies in the integration of environmental aspects, with the application of life cycle assessment (LCA) methodology, together with economic criteria for the selection of best alternatives. A case study illustrates how the connection of neighboring wastewater systems by constructing an extra pipeline provides positive results in the economic assessment, and in the majority of the LCA categories used in the global environmental assessment. The consideration of local environmental constraints suggests that the usage of the connection should be limited to periods when the minimum ecological flow in the river section between the discharges of the two WWTPs is maintained. In this particular case, the scenario that promotes the usage of the connection between the two WWTPs (but with some restrictions in dry weather periods) is preferred because it provides cost savings of 45,053€·year−1 and satisfies environmental criteria. A scenario analysis has been conducted to evaluate the influence of the pipe length on both economic and environmental aspects and the influence of individual cost terms on the economic assessment.