Comparison and assessment of the nutrient removal capacity by reed grass (Phragmites australis L.) and vetiver (Vetiveria zizanioides L.)

Abstract

The paper presented results of the comparative assessment of nutrient absorption capacity by plants, including reed grass (Phragmites australis L.) and vetiver (Vetiveria zizanioides L.). The constructed wetland models were designed with experiments (i) - Loading 1 (T1): reed grass (S1), vetiver (V1) + control (C1); (ii) - Loading 2 (T2): reed grass (S2), vetiver (V2) + control (C2); (iii) - Load 3 (T3): reed grass (S3), vetiver (V3) + control (C3). The study investigated the surface water quality parameters including nutrients such as TKN (Total Kieldalh Nitrogen), ammonium (NH4-N), nitrite (NO2-N), nitrate (NO3-N), total phosphorus (TP) and phosphate (PO43-). Results showed that there was significantly decreasing change related to pollutant concentration in the tanks. The studied results showed that the water treatment efficiency of Loading 1 (T1) possessed highly nutrient absorption capacities such as nitrogen and phosphorus. Comparing the nitrogen and phosphorus removal efficiency, there was no statistically significant difference between reed grass and vetiver in the same loading (P>0.05). In general, in the same loading levels, the plants’ nutrient removal efficiencies were often higher than the control experiments (P<0.05). The effluent findings illustrated some parameters of water quality that met to National Technical Regulation of surface water quality for agricultural irrigation purposes (QCVN 08-MT:2015/BTNMT). Therefore, the constructed wetland technology obtained highly effective characteristics and supplying the environmental friendly advantages.