POTENTIAL USE OF Scirpus littoralis AND Typha orientalis FOR NITROGEN AND PHOSPHORUS REMOVAL FROM INTENSIVE WHITELEG SHRIMP WASTEWATER

Abstract

The rapid development of whiteleg shrimp farming in the Vietnamese Mekong Delta has an adverse impact on the environment due to large amount of nitrogen and phosphorus content in wastewater and pond sludge/sediment. Phytoremediation is a promising technique to use plant for mitimigating environmental impacts from intensively whiteleg shrimp culture. Selection of potential plant species having fast growth, high biomass, high adaptive and nutrient uptake capacity in wetlands condition is one of the steps for the success of this technique. Growth responses, nitrogen and phosphorus removal process were investigated at three water levels of +15 cm, +30 cm and +45 cm with plants (Typha orientalis and Scirpus littoralis) and without plants (as control treatment). They were arranged in a completely randomized design with three replications. The plants were supplied wastewater from intensive whiteleg shrimp tanks once every two weeks. Waterlogged assessment was conducted for 71 days. Water levels significantly affected plant growth rate and nutrient removal capacity. S. littoralis grew well with a lower survival rate and had no statistical reduction of biomass compared to T. orientalis at the highest water level of +45 cm. T. orientalis had the best perfromance in growth and biomass responses to waterlogged at water levels of +15 cm and +30 cm. The results indicated that S. littoralis was the best of choice to grow in waterlogged condition of the shrimp pond for maintaining water quality.