Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

‘Green Clean:’ Researchers Determining Natural Ways To Clean Contaminated Soil

22.09.2009
Researchers at North Carolina State University are working to demonstrate that trees can be used to degrade or capture fuels that leak into soil and ground water. Through a process called phytoremediation – literally a “green” technology – plants and trees remove pollutants from the environment or render them harmless.

Through a partnership with state and federal government agencies, the military and industry, Dr. Elizabeth Nichols, environmental technology professor in NC State’s Department of Forestry and Environmental Resources, and her team are using phytoremediation to clean up a contaminated site in Elizabeth City, N.C.

March 2006: The Coast Guard site before trees were planted.
Phytoremediation uses plants to absorb heavy metals from the soil into their roots. The process is an attractive alternative to the standard clean-up methods currently used, which are very expensive and energy intensive. At appropriate sites, phytoremediation can be a cost-effective and sustainable technology, Nichols says.

The Coast Guard site was planted with a mixture of fast-growing trees such as hybrid poplars and willows to prevent residual fuel waste from entering the Pasquotank River by ground water discharge. About 3,000 trees were planted on the five-acre site, which stored aircraft fuel for the Coast Guard base from 1942 until 1991. Fuels had been released into the soil and ground water over time. Efforts to recover easily extractable fuel using a free product recovery system – also called “oil skimmers” – had stalled so other remedial options were considered before choosing phytoremediation.

“We knew that tree growth would be difficult on portions of the site due to the levels of fuels in the soil and ground water, but, overall, we thought the trees could keep this contamination from moving toward the river by slowing ground water flow,” Nichols said. “Trees need water for photosynthesis so they absorb water from the ground; that process can slow the amount of ground water flowing toward the river.”

July 2009: The same view in 2009. Some trees are now more than 30 feet tall. Bare spots indicate where bunkers were located and contamination is greatest.

In the process of absorbing water from the ground, trees can take up fuel contaminants. Some contaminants will be degraded by trees during this process while others will be released into the air by tree leaves and stems. “We wanted to demonstrate that the trees would first slow the movement of fuel toward the river,” Nichols said.

Trees can also increase the abundance and diversity of soil microorganisms around their roots. Some of these soil microorganisms will degrade the fuel still remaining in the ground. “This can be a slower process, but we also want to show that trees will remove the remaining fuel footprint over time,” Nichols continued.

Initially, 500 hybrid poplar and willow trees were planted in 2006. Another 2,500 trees were planted in 2007. “Our initial results are very encouraging, and amounts of fuel in the ground have decreased much faster than anticipated,” Nichols said, “but there is still much to learn about how trees can impact residual, weathered fuels over time. There are two areas on the site where trees do not do well, but, overall, tree growth and survival are impressive.” The Coast Guard has recognized the value of phytoremediation from this study, and has established two additional phytoremediation systems at different locations on base.

The project received a $240,584 grant from the U.S. Environmental Protection Agency and the N.C. Department of Environment and Natural Resources’s (NCDENR) Division of Water Quality 319 program, and an additional $15,000 grant from British Petroleum North America to establish the demonstration site. Nichols worked with Brad Atkinson (NCDENR), Dr. James Landmeyer (U.S. Geological Survey), J.P. Messier (U.S. Coast Guard), and Rachel Cook, a graduate student at NC State, to design and implement the phyto-demonstration site. NC State was recently awarded an additional EPA/NCDENR 319 grant to continue monitoring the site for tree growth and fuel reduction, tree toxicity to fuels, changes to ground water levels and flow, and how fuel contamination is actually removed by trees.

Caroline M. Barnhill | EurekAlert!
Further information:
http://www.ncsu.edu

More articles from Ecology, The Environment and Conservation:

nachricht Plant seeds survive machine washing - Dispersal of invasive plants with clothes
11.09.2018 | Gesellschaft für Ökologie e.V.

nachricht Air pollution leads to cardiovascular diseases
21.08.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists present new observations to understand the phase transition in quantum chromodynamics

The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.

This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.

Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

Im Focus: Finding Nemo's genes

An international team of researchers has mapped Nemo's genome

An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

 
Latest News

Astrophysicists measure precise rotation pattern of sun-like stars for the first time

21.09.2018 | Physics and Astronomy

Brought to light – chromobodies reveal changes in endogenous protein concentration in living cells

21.09.2018 | Life Sciences

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

VideoLinks
Science & Research
Overview of more VideoLinks >>>