Phytoremediation performance of Lemna communities in a constructed wetland system for wastewater treatment

摘要: Abstract Duckweeds are considered suitable plants for bioremediation of wastewaters because they can tolerate and take up diverse pollutants large quantities nutrients. They have year-round vegetative growth that reach very high rates using wastewater nutrients accumulate intracellularly or be utilized to produce new biomass. The constructed wetland services the town Forano (Central Italy) is composed three interconnected, but distinct, treatment pools (P1, P2, P3). In this study phytoremediation performance whole system was assessed taking into consideration pH, temperature, oxygen, nitrates, phosphates, sulphates, pathogenic bacteria (Escherichia coli) at inlet outlet each pool once per season over a year. remediation efficiency P2 lower than in P1 P3, shown due an extended, dense free-floating Lemna mat. mat thick enough (18–30 mm) block light penetration, heat gas exchange underlying water resulting dark, cool near-anaerobic conditions. These conditions limited aerobic biodecomposition processes natural control E. coli population. fronds were highly necrotic became source nutrients, by increase nitrates phosphates from outlet. use often important, it here active management interventions required should involve periodic harvesting avoid over-development formation necromass.