The low volume batches of highly-concentrated wastewater discharged from land-based marine recircu-lating aquaculture systems are ideally suited for treatment by halophyte planted constructed wetlands.
To evaluate the role of plants and the effect of planting density on yield and performance in small-scalesaline constructed wetlands (CWs), NH4++NO3−+NO2−= total dissolved inorganic nitrogen (TDIN) anddissolved inorganic phosphorus (DIP) were measured at regular intervals over 24 hperiods.
CWs were planted with the halophyte Salicornia europaea at high- and low-densities and were compared to the performance of unplanted controls. S. europaeaplants were cropped regularly to assess potential commer-cial yield at the two densities.
There was no significant effect of planting density on performance or crop
yields and planted beds consistently outperformed the control beds removing 62.0 ± 34.6 mmol N m
−2d−1(34–73% of influent TDIN) compared to 23.0 ± 26.8 mmol N m−2d−1(−1% to 41% of influent TDIN) bycontrol beds.
Results for DIP were less clear, significant removal occurred only once, with reduction
of 18.3± 5.0 mmol P m−2d−1by planted beds and 18.1± 2.6 mmol P m−2d−1by the unplanted controls.
The results demonstrate the effectiveness of halophyte-planted CW in treatment of marine aquaculture wastewater.