THE EFFICIENCY OF SODIUM REMOVAL BY DECORATIVE PLANT SPECIES AND ALGAE IN THE FLOATING TREATMENT WETLAND

The excess Na content in water can cause serious environmental and health problems. Most of the previous studies have indicated the potential of constructed wetlands (CW) in sodium (Na) removal from synthetic water in controlled conditions. To the best of our knowledge, this is the first study to investigate the efficiency of the floating treatment wetlands (FTW) for the removal of Na from the polluted urban river. The present study also expands our knowledge of phytoremediation potential of rarely or never used decorative terrestrial and aquatic plant species in CW or FTW. The results imply that proposed. FTW model can ensure efficient Na removal. Even though the efficiency was negative or low during the first 3 treatment cycles, FTW was able to remove Na from polluted water by the end of water treatment. The highest Na removal efficiency of 44% had cell 1 with Phragrnites australis followed by 43% in cell 4 with decorative macrophytes (Iris pseudacorus, Iris sihirica 'Petry's Blue', Alisma plantago - aquatica, Lythrum salicaria, Menyanthes trifoliata) and cell 3 with P. australis and Canna indica (25%). Cell 2 planted with C indica showed the lowest efficiency of 5%. Species A. plantago aquatica had good potential for Na accumulation from water. Also, it can be assumed that species M trifoliata had a share in the Na removal. Translocation of accumulated Na from belowground biomass to shoots was very low in all species except M trifoliata. Algae Cladophora glomerata enabled further water polishing with maximum Na removal efficiency of 23% in cell 5 at the end of water treatment. Further studies need to be done to investigate all mechanisms responsible for Na removal in FTW and to ensure proper species selection for Na removal in floating treatment wetlands.