Nitrate removal from polluted water by using a vegetated floating system

Nitrate (NO3-) water pollution is one of the most prevailing and relevant ecological issues. For instance, the wide presence of this pollutant in the environment is dramatically altering the quality of superficial and underground waters. Therefore, we set up a floating bed vegetated with a terrestrial herbaceous species (Italian ryegrass) with the aim to remediate hydroponic solutions polluted with NO3-. The floating bed allowed the plants to grow and achieve an adequate development. Ryegrass was not affected by the treatments. On the contrary, plant biomass production and total nitrogen content (N-K) increased proportionally to the amount of NO3- applied. Regarding to the water cleaning experiments, the vegetated floating beds permitted to remove almost completely all the NO3- added from the hydroponic solutions with an initial concentration of 50, 100 and 150 mg L-1. Furthermore, the calculation of the bioconcentration factor (BCF) indicated this species as successfully applicable for the remediation of solutions polluted by NO3-. In conclusion, the results highlight that the combination of ryegrass and the floating bed system resulted to be effective in the remediation of aqueous solutions polluted by NO3-. (C) 2015 Elsevier B.V. All rights reserved.