Potential of a polyculture of <i>Arundo donax</i> and <i>Typha latifolia</i> for growth and phytotreatment of wastewater pollution

Abstract

Arundo donax and Typha latifolia are emergent macrophyte species that commonly reproduce in humid areas during warm months. This study investigated the growth and pollutant removal capacity of these two species planted in polyculture in a vertical flow filter bed for rural wastewater treatment. Plant shoot height was monitored and biomass production and nutrient uptake were assessed. Water physicochemical parameters were also monitored. A. donax showed higher height elongation (288 cm), phytomass production (2.4 kg dry biomass/m²) and nitrogen uptake (21.1 mg/kg DW) than did T. latifolia. Phosphorus and potassium retention was identical for both species. The macrophyte bed achieved higher removal rates for biochemical oxygen demand (BOD) (76%), chemical oxygen demand (COD) (82%), total suspended solids (TSS) (96%), total Kjeldahl nitrogen (TKN) (33%) and total phosphorus (TP) (46%), compared to an unplanted basin. The macrophyte species used were able to grow and to contribute to the rural wastewater purification in the adopted experimental constructed wetland.

Key words: Arundo donax, Typha latifolia, wastewater, phytotreatment, nutrient uptake, constructed wetland.