Production and energy value of phragmites australis obtained from two constructed wetlands.

Common Reed (Phragmites australis (Cav.) Trin. ex Steud.), a perennial C3-grass, is the most commonly used plant species in constructed wetlands for wastewater treatment in Italy and is considered a potential biomass crop in Europe because it is high yielding and has low input requirements. Aboveground biomass for generating heat and power have been measured in two full-scale Horizontal Sub Surface Flow Constructed Wetlands (H-SSF CWs) case studies in Italy: a CW for tertiary treatment of piggery manure located in Veneto Region (N-Italy), and another for tertiary treatment of a municipal wastewater plant in Sicily (S-Italy). Both CWs were planted with Phragmites spp. at a density of 4 rhizomes/m2. Wastewater samples were analyzed for the evaluation of the chemical characteristics. The yield was measured at different harvesting times (early, mid and late winter). Dried plant samples were tested for the determination of the Higher Heating Value (HHV) and Lower Heating Value (LHV). Common Reed beds that are dense and homogeneous under Mediterranean climatic conditions are able to produce high annual biomass yield (approximately 105 t/ha). The aboveground biomass harvested in Catania has lower values of moisture (43.9%) compared to that in Padova (64.6%). This permits a higher LHV to be obtained during the combustion process.