Vetiver System

Abstract: Aims Vetiver grass – Chyrsopogon zizanioides (L.) Roberty is a known plant tolerant to heavy metals and its use as an alternative method for rehabilitation of iron ore mine-soil has been investigated. Methods A pot experiment was performed over a period of three months and the performance of vetiver grass on heavy metal-rich soil from iron ore mine was assessed. The presence of the following heavy metals – Fe, Mn, Zn, Cu, Pb, Ni, Cr and Al were assessed in mine-soil and their uptake by vetiver grass system was evaluated. In addition, oxidative and genotoxic stress were used to monitor the changes over the period. Results Physico-chemical characterization and metal analysis revealed that vetiver plant is a good phytostabilizer. The plant is a potential accumulator of heavy metals and the root parts of the plant accumulated higher metal concentrations than the shoot. The high proportions of metals inhibited the chlorophyll content of leaves, but stimulated the accumulation of proline and lipid peroxidation. Enhanced activities of catalase (CAT), guaiacol peroxidase (GPOD) and glutathione (GSH) implied that different mechanisms existed to detoxify reactive oxygen species (ROS) in the shoot of the plants. Genotoxicity assays demonstrated the absence of genetic instability or DNA damage in the plants. Conclusion Vetiver can be used as an excellent candidate for remediation and restoration of iron-ore mine spoil-dumps.

Abstract: Palm oil mill effluent (POME), a pollutant produced by the palm oil industry, was treated by the Vetiver system technology (VST). This technology was applied for the first time to treat POME in order to decrease biochemical oxygen demand (BOD) and chemical oxygen demand (COD). In this study, two different concentrations of POME (low and high) were treated with Vetiver plants for 2 weeks. The results showed that Vetiver was able to reduce the BOD up to 90% in low concentration POME and 60% in high concentration POME, while control sets (without plant) only was able to reduce 15% of BOD. The COD reduction was 94% in low concentration POME and 39% in high concentration POME, while control just shows reduction of 12%. Morphologically, maximum root and shoot lengths were 70 cm, the number of tillers and leaves was 344 and 86, and biomass production was 4.1 kg m−2. These results showed that VST was effective in reducing BOD and COD in POME. The treatment in low concentration was superior to the high concentration. Furthermore, biomass of plant can be considered as a promising raw material for biofuel production while high amount of biomass was generated in low concentration of POME.

Abstract: While the oil palm industry has been recognized for its contribution towards economic growth and rapid development, it has also contributed to environmental pollution due to the production of huge quantities of by-products from the oil extraction process. A phytoremediation technique (floating Vetiver system) was used to treat Palm Oil Mill Secondary Effluent (POMSE). A batch study using 40 L treatment tanks was carried out under different conditions and Response Surface Methodology (RSM) was applied to optimize the treatment process. A three factor central composite design (CCD) was used to predict the experimental variables (POMSE concentration, Vetiver plant density and time). An extraordinary decrease in organic matter as measured by BOD and COD (96% and 94% respectively) was recorded during the experimental duration of 4 weeks using a density of 30 Vetiver plants. The best and lowest final BOD of 2 mg/L was obtained when using 15 Vetiver plants after 13 days for low concentration POMSE (initial BOD = 50 mg/L). The next best result of BOD at 32 mg/L was obtained when using 30 Vetiver plants after 24 days for medium concentration POMSE (initial BOD = 175 mg/L). These results confirmed the validity of the model, and the experimental value was determined to be quite close to the predicted value, implying that the empirical model derived from RSM experimental design can be used to adequately describe the relationship between the independent variables and response. The study showed that the Vetiver system is an effective method of treating POMSE.

Abstract: The Vetiver System is based on the use of vetiver grass (Vetiveria zizanioides L.) for various applications in erosion and sediment control. The Vetiver System was first developed by the World Bank for soil and water conservation in India in the 1980s. Research and development conducted in Queensland and overseas since then have also shown this system to be a very effective in: • Water erosion control in agricultural lands such as flood erosion control Darling Downs, where it has been used to replace strip crop layouts, in contour bank substitution and in gully stabilisation. As well, recent research on the use of vetiver grass to control erosion of drains in acid sulfate soils and to improve water quality will be discussed. • Erosion and sediment control on steep slopes as a bioengineering technique. It has been used successfully for steep batter stabilisation on highway and railway constructions, and for protection of mine infrastructure such as steep outer batter slopes on dams. • Mine rehabilitation, vetiver grass is highly tolerant to heavy metals as well as to extreme edaphic and climatic conditions. This makes it an ideal species for colonising and ameliorating landfills and tailings dams.

Abstract: Clean water is becoming one of the most scarce and valuable resources in the twenty first century as its supply is finite and its traditional source is easily polluted by industries and population growth. Existing and traditional wastewater treatment methods are expensive and in most cases are either impractical or unsuitable for smaller communities and certain industries. The Vetiver System was first developed for soil and water conservation purposes but tin the last six years its role has been extended into environmental protection field, particularly in the field of wastewater treatment and solid waste landfills. Research in Australia and China has shown that VS is a very effective method of treating polluted water, domestic effluent, industrial wastewater and landfill leachate.