  Sustainable water management has become an urgent challenge due to irregular
water availability patterns and water quality issues. The effect of climate
change exacerbates this phenomenon in water-scarce areas, such as the
Mediterranean region, stimulating the implementation of solutions aiming to
mitigate or improve environmental, social, and economic conditions. A novel
solution inspired by nature, technology-oriented, explored in the past years,
is constructed wetlands. Commonly applied for different types of wastewater due
to its low cost and simple maintenance, they are considered a promising
solution to remove pollutants while creating an improved ecosystem by
increasing biodiversity around them. This research aims to assess the
sustainability of two typologies of constructed wetlands in two Italian areas:
Sicily, with a vertical subsurface flow constructed wetland, and Emilia
Romagna, with a surface flow constructed wetland. The assessment is performed
by applying a cost-benefit analysis combining primary and secondary data
sources. The analysis considered the market and non-market values in both
proposed scenarios to establish the feasibility of the two options and identify
the most convenient one. Results show that both constructed wetlands bring more
benefits (benefits-cost ratio, BCR) than costs (BCR > 0). In the case of
Sicily, the BCR is lower (1) in the constructed wetland scenario, while in its
absence it is almost double. If other ecosystem services are included the
constructed wetland scenario reach a BCR of 4 and a ROI of 5, showing a better
performance from a costing perspective than the absence one. In Emilia Romagna,
the constructed wetland scenario shows a high BCR (10) and ROI (9), while the
scenario in absence has obtained a negative present value indicating that the
cost do not cover the benefits expected.
