Poplar Trees Could Reduce Water Pollution

Researchers at the University of Missouri-Rolla are studying the use of fast-growing poplar trees as an inexpensive tool to reduce water pollution.

“Who would have thought that trees could help purify water?” said Joel Burken, a UMR professor of civil engineering, who is leading a team of graduate and undergraduate students in the research effort.

Burken and his team are working with a new idea in environmental engineering, known as phytoremediation — using plants to clean up pollutants. “I hope that phytoremediation will revolutionize the process of remediating contaminated sites,” said Burken. “The effort could replace the current methods now being used to cleanse contaminated soil and groundwater.”

Some of those current methods of water purification consist of pumping, heating, and baking the ground to extract pollutants.

“All of those measures, especially pumping, are incredibly expensive,” said Burken. “In contrast, phytoremediation uses living plants to reduce contaminated soil, sludges, and groundwater in a less expensive way.”

Phytoremediation has also been expanded to provide safer methods of cleaning metals, crude oil, and landfill leachates, said Burken.

Working in conjunction with the University of Connecticut and Ecolotree Inc., an environmental engineering company, Burken plans to cut costs by using poplar trees to remove the pollutants from water tables that may be used for drinking water.

One method involves incorporating genetically enhanced microbes with the planting of the trees. This type of genetic engineering gives the microbes the ability to break down pollutants naturally, Burken says.

University of Connecticut researchers do the actual genetic engineering part of the process, creating the enhanced microbes. Burken carries on the process by inoculating cuttings from the trees. Burken tests the trees to see the impacts of the genetic engineering.

So far so good, Burken says. “In one case, 1,700 poplar trees were planted on a contaminated Navy site. The efforts saved the site roughly $5 million in the clean-up process.”

In addition to the assistance from the University of Connecticut, Ecolotree Inc. supplies Burken with the resources that could enable phytoremediation to become marketable.

“The process has been in the field for about eight years,” Burken says. “But it has recently been noticed by experts in the field and even younger scientists. I get questions from high school and college students across the country wanting to do projects.”

The future for phytoremediation is somewhat uncertain, but Burken believes it is advancing in the remediation field. “While there are still many questions left unanswered about exactly why this process works, it seems to work,” he says. “But we don’t know exactly why. It is just a simple but elegant process that does the job.”