Abstract:
The objectives of this research were to study the efficiency of vetiver grass in landfill leachate treatment; and growth and nutrient (nitrogen and phosphorus) in shoot and root of vetiver grass. Two vetiver grass ecotypes (Surat Thani and Songkhla3) and no plant as control; and 3 concentration levels of landfill leachate were used. The average COD of raw leachate (RL), treated leachate (TL) and canal water (CW) were 940.67, 210.67 and 60.44 mg/l, respectively. The average TKN were 219.30, 183.80 and 19.56 mg/l, respectively. The average TP were 12.75, 4.48 and 2.53 mg/l, respectively. Vetiver grasses were cultivated with floating platform technique in plastic containers with 55 centimeters in upper diameter and 30 centimeters in height for 12 weeks. The results showed that the efficiency of vetiver grass for treatment of different landfill leachate concentration were significantly different. The highest removal percentages of COD, TP and chloride were found in TL with average percentages of 84.77-86.36, 86.46-89.58 and 18.70-21.58 %, respectively. The highest removal percentage of suspended solid was found in RL with average percentage of 97.04-98.19 %. The highest removal percentage of TKN was found in CW with average percentage of 95.40-96.76 %. The removal percentages of different vetiver ecotypes were not significantly different. However, the study showed that the experimental sets with vetiver grass had significantly higher removal percentages than a control set (without plant). For growth and nutrient of vetiver grass, in RL, Surat Thani had highest growth and nutrient accumulation. In TL and CW, Songkhla3 had highest growth and nutrient accumulation. In conclusion, the overall results suggested that the optimal condition for vetiver grass cultivated with floating platform in landfill leachate treatment should be planted with Surat Thani if landfill leachate had high SS, COD and nutrients. However, if landfill leachate had low SS and COD and nutrients, Songkhla3 could be planted.