Featured Expert: Linda Weavers

Linda Weavers lab photoLinda Weavers

Professor, Department of Civil, Environmental and Geodetic Engineering

Protecting Water Quality and Sustainability

Boiled down, the motivating force behind Linda Weavers’ research is straightforward — develop new technology to help reduce energy costs and eliminate harmful pollutants from the environment.

Weavers is the John C. Geupel Chair in Civil Engineering; a professor in the Department of Civil, Environmental and Geodetic Engineering; and co-director of the National Institute for Water Resources, Water Resources Center for the state of Ohio.

Much, though not all, of her work is focused on remediating the damage pollutants can cause to the ecosystem, especially as they relate to water.

Water contamination due to pharmaceuticals and personal care products in wastewater is of increasing concern, she says. Because the accessibility and use of these products is ubiquitous, it could be creating long-range consequences.

“With some of these pollutants, if they reduce the ability of the human race to reproduce,” Weavers says, “that is the ultimate sustainability problem.”

“If we consume a very low continual dose, how does it affect us and the ecosystem?” she says, noting that scientists already are finding that pharmaceuticals and personal care products have negative effects on certain species of fish and frogs. “Being able to see this effect in humans is challenging. To date, scientists have not been able to link low-level exposure to any observable effects.”

In August, Weavers began an 11-month research sabbatical at the University of Udine, in northeastern Italy. In collaboration with an Italian professor who has a working relationship with a dredging company, she and colleagues will look at developing technology to remove significant mercury contamination from local rivers and lagoons.

“We are trying to figure out how to get the contamination out of the water cost effectively without changing or increasing risk to the water systems,” she says. “We are developing a kind of a ground truth in terms of how new technology could be used with dredging operations.”

Weavers has done significant work at Ohio State successfully using ultrasound to treat and remove contamination, such as chemical pollutants, from water sediment including sand, silt and clay. She has experimented with ultrasound at lower frequency and higher power than that used for imaging.

The process creates cavitation bubbles, which are microscopic bubbles formed from the oscillating ultrasonic pressure wave. When a cavitation bubble collapses due to a reduction in pressure prior to an increase in pressure, it creates extreme heat (5,000 to 10,000 degrees Kelvin) and “unique things can happen,” she says, because the bubbles are very transient, growing and collapsing, and creating a variety of effects.

“This is kind of like a mini incinerator that we have there, and if we can get contaminants inside that bubble, we can essentially degrade them by high temperature,” Weavers says.

Recently, Weavers began collaborating with fellow Ohio State faculty members Henk Verweij of the Department of Material Sciences and Engineering and Paula Mouser of the Department of Civil, Environmental and Geodetic Engineering on developing next-generation membranes — filters with distinct pore sizes —to remove contaminants in water. The research is focused on creating membranes less prone to getting gummed up by pollutants.

Holding much promise for scientists are membranes with pores so small they will filter out salt, which could possibly be used to make seawater drinkable.

“As the world is becoming more and more water stressed, the potential of using membranes for reclaiming sea water is becoming more and more of interest,” she says. “It is a very high-energy process, but it is something that is being looked at as we need water.”

The extraction of energy from Ohio shale has also begun attracting the attention of the Water Resources Center, which Weavers co-directs at Ohio State. Researchers there are working to develop baseline measurements prior to fracturing for oil and gases.

“We are trying to get information to see if it is an environmental problem or where it is a problem so that we can move forward without creating more contamination issues,” she says. “We are planning to monitor to know what is happening so we can then make recommendations about how to change the system or how it needs to be run to reduce risk.”

Weavers came to Ohio State in 1998 after obtaining her undergraduate degree in civil engineering at the University of Minnesota and her master’s and doctoral degrees in environmental engineering science at the California Institute of Technology.

In 2002, Weavers started Ohio State’s Future Engineers’ Summer Camp for 8th-grade girls through a National Science Foundation CAREER grant that had been elevated to a Presidential Early Career Award for Scientists and Engineers. She launched and ran the program in collaboration with the Women in Engineering program and the NSF-funded Environmental Molecular Science Institute.

“It seemed like there was a need to have something to keep girls interested in science and math, the feeder disciplines to engineering, at a critical time in their education when they often shun these subjects and lose confidence in their abilities,” she says. “The goal is to expose girls to engineering generally so they learn what engineering is and see that it can be fun.”

The Scotts Miracle-Gro Co. now funds the program, renamed WiE Grow, which is run by the Women in Engineering program.

Weavers knows first-hand the value of promoting early interest in engineering.

“The idea of solving problems and being good at math and science, combined with my interest in the outdoors and water, really brought me to environmental engineering,” she says.

There were also personal influences. Her father, Mark, is an engineer, and a teacher in high school chemistry and physics as well as a professor at Caltech also influenced her. In particular, her 7th-grade teacher, Jack Moyer, inspired her love for environmental science when she attended an American school in Japan, where her father had been transferred for work with the 3M Co.

“We had a weeklong field trip to a volcanic island off the coast near Tokyo,” she remembers. “We had a week of exploring nature and ecology and got to snorkel in a tidal pool.

“The teacher was a marine biologist by training, and he was really inspirational and able to get kids excited about environmental and marine sciences,” she says. “A teacher can be very influential in young people’s lives.”

On the web:

Linda Weavers:  http://www2.ceegs.ohio-state.edu/~lweavers/

email: weavers.1@osu.edu