After a marine life disaster in central Viet Nam in 2016 due to poorly treated steel industry wastewater and pipe cleaning solutions, the Formosa Steel Corporation has been improved their wastewater treatment systems. Besides, an effluent polishing and buffer pond – wetland system has to be built. The study team has run the 500 m2 pilot wetland aiming to figure out optimum design parameters such as: balancing requirements of hydraulic conductivity, hydraulic headloss, filtration efficiency and plant growth. | Design of wetland system for wastewater quality improvement at Formosa Ha Tinh steel company