Efficiency of Salicornia neei in removing nitrogen and producing biomass from a hypersaline and artificial wetland to treat aquaculture effluent

BackgroundOne of the main challenges for the sustainability of land-based marine aquaculture systems is the treatment of saline effluent saturated with nitrogenous waste. In this study, we evaluated the potential of Salicornia neei, a halophyte plant native to South America, to remove nitrogen and produce biomass in sandy substrate with nitrogen concentrations similar to marine aquaculture effluent. Plants were collected from the natural environment and cultivated under three treatments: 1) seawater fertilized with nitrate + ammonium (Nit+Amm); 2) seawater fertilized with nitrate (Nit); and 3) seawater without fertilizer (Control). ResultsThe nitrogen removal rate increased from 1.67 to 2.76 mg L-1 d-1 and from 1.95 to 2.96 mg L-1 d-1 in the Nit+Amm and Nit treatments, respectively. In the two treatments, nitrogen removal efficiency varied between 87 {+/-} 0.39 and 92 {+/-} 0.40%. The salinity increased from 40 to 52 g L-1 of NaCl during the experiment, with no observed detrimental effects on the nitrogen removal efficiency. At the end of the crop cycle, the biomass production was not significantly different between the treatments of Nit+Amm and Nit (mean Nit+Amm = 3,584 {+/-} 249.3 g; mean Nit 3,004 {+/-} 249.3 g) but was different with respect to the control (mean Control = 1,527 {+/-} 70.0 g). ConclusionsOur results demonstrate that artificial wetlands of S. neei can be used for wastewater treatment in marine aquaculture and for biomass production in South America.