A cost-effectiveness analysis of seminatural wetlands and activated sludge wastewater-treatment systems.
A cost-effectiveness analysis was performed to evaluate the competitiveness of seminatural Free Water Surface (FWS) wetlands compared to traditional wastewater-treatment plants. Six scenarios of the service costs of three FWS wetlands and three different wastewater-treatment plants based on active sludge processes were compared. The six scenarios were all equally effective in their wastewater-treatment capacity. The service costs were estimated using real accounting data from an experimental wetland and by means of a market survey. Some assumptions had to be made to perform the analysis. A reference wastewater situation was established to solve the problem of the different levels of dilution that characterize the inflow water of the different systems; the land purchase cost was excluded from the analysis, considering the use of public land as shared social services, and an equal life span for both seminatural and traditional wastewater-treatment plants was set. The results suggest that seminatural systems are competitive with traditional biotechnological systems, with an average service cost improvement of 2.1-fold to 8-fold, according to the specific solution and discount rate. The main improvement factor was the lower maintenance cost of the seminatural systems, due to the self-regulating, low artificial energy inputs and the absence of waste to be disposed. In this work, only the waste-treatment capacity of wetlands was considered as a parameter for the economic competitiveness analysis. Other goods/services and environmental benefits provided by FWS wetlands were not considered.
Mannino
Ilda
I
Venice International University, Isola di San Servolo, Venice, 30100, Italy.
Franco
Daniel
D
Piccioni
Enrico
E
Favero
Laura
L
Mattiuzzo
Erika
E
Zanetto
Gabriele
G
D003362:Cost-Benefit Analysis; D007558:Italy; D008962:Models, Theoretical; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000191:economics / Q000379:methods; D014876:Water Pollution / Q000517:prevention & control*; D018508:Water Purification / Q000191:economics / Q000379:methods; D053833:Wetlands
D012722:Sewage