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Also called elephant grass, giant miscanthus is a species of grass garnering attention for its value as a biofuel. But even more promising is the plant’s capacity to help reclaim contaminated land, like the land around abandoned mines.
Currently, a team of researchers from West Virginia University is using giant miscanthus to reclaim former surface coal mines around the Ohio River Valley, a large area in the eastern-central United States. The plant species is thriving in once-barren land, with its root systems producing a layer of topsoil.
According to the West Virginia research team, giant miscanthus grows in size at five to six times the rate of standard agricultural crops, even without fertilizer or other interventions. Because it can be turned into a range of different biofuels, giant miscanthus is a very appealing solution for land remediation.
One conventional remediation technique involves digging up the tainted soil and getting rid of it as hazardous waste material. This technique demands considerable amounts of energy and resources. Conversely, land remediation through the growth of plants, also referred to as phytoremediation, is fairly cheap, greener and less energy-intensive. It is also effective for locations with small and medium levels of contaminants. Broader ecological benefits include greater aesthetic value, the establishment of better wildlife habitats, and higher land value. Phytoremediation also meets the economic, ecological, and social thresholds for what is considered sustainable development.
Giant miscanthus has been shown to be among the best plants for phytoremediation, effectively to remediating soil around abandoned cadmium, coal, lead and zinc mines. One of the characteristics that make it especially suited to phytoremediation is the low transfer of toxins to its air-facing parts. Most of the compounds absorbed by the grass stay in its root system. Therefore, most of the plant can be safely used.
Despite the fact that concentrations of toxins in useable parts of giant miscanthus grown on degraded land are fairly low, some caution is recommended in its collection and usage. As noted previously, it should be used as bio-fuel, and not as source material for personal products. If the levels of toxins are greater than allowable amounts, it could be mixed with clean biomass, to bring down pollutant levels for the resulting biofuel.
Using giant miscanthus to reclaim old mines and other similar lands has another benefit: the reduction of emissions. Critically, the use of miscanthus as a cleaner-burning biofuel reduces emissions by reducing reliance on fossil fuels.
Growing miscanthus can also reduce emissions by sequestering carbon in topsoil. The grass happens to be particularly efficient at capturing carbon dioxide and storing it in the soil with its unique root system. According to researchers from Ohio State University who have been studying the carbon sequestration abilities of miscanthus, a large plot of the grass could be massive carbon sinks and combined with its use as a biofuel; the cultivation of miscanthus could be a carbon-negative system.
However, there are legitimate emissions concerns about the burning of biomass. Skeptics don’t regard biomass a carbon-neutral fuel source. One issue associated with miscanthus is the transport of it from relatively remote locations for conversion into biofuel, which can considerably raise its carbon footprint.
Supporters say the advantages of miscanthus surpass the possible concerns, and past study has revealed the possibility of miscanthus being at least a carbon-neutral fuel, with the grass soaking in enough carbon to compensate for emissions released by burning.
Even some skeptics admit the way the miscanthus and other biofuels are regulated is critical to their usefulness as an emissions-mitigating energy source. Even if the grass isn’t widely adopted as a biofuel, it still holds considerable value as a tool for reclaiming former mining areas and similar sites.