Pollutant removal efficiency of a pilot-scale Horizontal Subsurface Flow in Sicily (Italy) planted with Cyperus alternifolius L. and Typha latifolia L. and reuse of treated wastewater for irrigation of Arundo donax L. for pellet productionResults of two-year tests under Mediterranean climatic conditions

Abstract

Constructed wetland systems (CWs) are developed biological technologies for the treatment and reuse of wastewater. The aims of this study were to evaluate the treatment performance of a pilot Horizontal Subsurface Flow system (HSSFs), to evaluate the reuse of treated wastewater (TWW) from CWs for the irrigation of giant reed (Arundo donax (L.)) and to assess the effects of TWW on the biomass yield of giant reed grown for pellet production. The research was carried out in Sicily (Italy) in a pilot-scale HSSFs which was fed with urban-treated urban wastewater following secondary treatment from an activated sludge wastewater treatment plant. Giant reed plots were irrigated with TWW from plantedunits, TWW from an unplanted-unit and with freshwater (FW). The pilot system was found to have excellent removal efficiency for all the parameters examined. The different treatment levels of irrigation did not affect significantly the growth and yield of giant reed ecotypes. Differences between heating values of above-ground biomass irrigated with FW and TWW were negligible. TWW from CWs can be used for the irrigation of species grown for energy purposes, thereby providing an alternative source of water, particularly in areas where water deficit in the agricultural sector is significant.