A series of investigations were conducted to evaluate the feasibility of using constructed wetlands to remove pollutants from seafood
processing wastewater. Six emergent plant species;Cyperus involucratus, Canna siamensis, Heliconia spp., Hymenocallis littoralis, Typha
augustifolia and Thalia deabata J. Fraser were planted in surface flow wetland. They were fed with seafood wastewater that was 50%
diluted with treated seafood wastewater from an aerated lagoon. All macrophytes were found to meet satisfying treatment efficiency(standard criteria for discharged wastewater) at 5 days hydraulic retention time (HRT). While C. involucratus, T. deabata and T. augustifolia met acceptable treatment efficacy at 3 days HRT. Nutrient uptake rate of these species was observed in the range of 1.43–2.30 g
Nitrogen/m2 day and 0.17–0.29 g Phosphorus/m2 day, respectively at 3 days HRT. The highest treatment performances were foundat 5 days HRT. Average removal efficiencies were 91–99% for BOD5, 52–90% for SS, 72–92% for TN and 72–77% for TP. Plant growth
and nitrogen assimilation were experienced to be most satisfactory for C. involucratus, T. deabata and T. augustifolia. Lower HRTsaffected contaminant removal efficiency for all species. C. involucratus, T. deabata and T. augustifolia can remove all contaminants effi-ciently even at the lowest hydraulic retention time (1 day).