Removal of nutrients and organic matter in a constructed wetland, in function of the development of the macrophyte Typha dominguensis Pers

Abstract

The constructed wetlands are based on the use of emergent macrophytes for wastewater treatment. It was assessed nutrient removal and organic matter in relation to the development of the macrophyte Typha dominguensis in a constructed wetland, fed with domestic wastewater from a stabilization pond system, compared to a control with no plants, and determining optimal time of pruning. The study was carried out during two periods, defined by present of inflorescence and pruning of vegetation. Highest organic matter removal efficiency was reported in the wetland during two periods, with values of 30.29 and 30.48% for COD, 34.63 and 31.63% for BOD, 43.9 and 52.4% for TSS, 42.9 and 60.8% for VSS. Nutrient removal did not show differences between wetland and control, with total removal of 45-55% for NH4+ and 48-50% for KTN. Phosphorous highest removal was achieved in control with 19.17 and 15.35% for each period. The growth of the plant and the nutrient removal and organic matter were correlated during the first period. Optimal harvest time was near to the eighth week. It is demonstrated the important role of Typha dominguensis in the process of organic matter removal, however more studies are needed to accurately determine the importance of the vegetation in nutrient removal.

Keywords

• constructed wetland
• organic matter
• Typha dominguensis
• wastewaters