Geologist to help clean Kansas groundwater

Dry cleaning chemicals

The Kansas Department of Health and Environment is cleaning up 65 sites throughout the state contaminated by dry cleaning chemicals.

Contamination on some of these sites came from more than one dry cleaner.

Money for the clean up comes from a trust fund. The fund charges a 2 1/2 percent fee on all dry cleaning bills, and $5 for every gallon of solvent that a dry cleaner buys.

KDHE inspects at least 20 of the state's 171 dry cleaners every year to try to prevent future spills.

Source: KDHE

By Michael C. Campbell

Special to The Capital-Journal

Almost half of the water consumed in Kansas comes straight out of the ground. A University of Kansas geologist just has received a five- year grant from the National Science Foundation to help keep that water clean.

Professor Rick Devlin got the money in August to study improvements to underground water treatment systems called permeable reactive barriers. These barriers go into the ground around toxic spills and prevent contaminated water from spreading.

The toxins migrate by dissolving in water that flows through the ground. PRBs neutralize any toxins that flow into them, before the contamination can reach somebody's well.

Devlin likes these barriers because the alternatives are expensive and may only partially solve the problem.

"Groundwater is easy to ignore," Devlin said, "By the time somebody notices the pollution, it's often spread quite extensively and digging up the contaminated ground rarely removes all the contaminants."

Leaving behind even a little contamination can cause a long-term pollution problem, according to Devlin.

For instance, pollution at an industrial site near Coffeyville had spread over an area nine football fields long and 30-feet deep before a 1996 cleanup. Removal of all the tainted dirt was impractical.

Instead, workers hemmed in the spill with two V-shaped trenches filled with clay. The impenetrable clay funneled all the dirty water through a PRB at the V's base.

The main contaminants in Coffeyville were two chemicals known by the acronyms TCE and TCA. These molecules are common ingredients in glues, solvents and industrial degreasers.

Dry cleaners also use TCE and its chemical cousin PERC, both of which are common groundwater contaminants. The PRBs that Devlin studies target dry cleaning fluids and related chemicals.

To build the PRB, workers first determine which way water will carry the contaminants. They then dig a trench to intercept the water and fill it with something that will capture and detoxify the contaminants.

Sometimes the trench gets a wet slop called guar, which food companies also use as a thickener for ice cream and soups. In the case of dry cleaning chemicals, the trench filling is a three-foot thick layer of steel from old cars ground into sand-grain sized pieces.

Iron molecules in the steel like to react with contaminated molecules.

"The steel molecules are like little live wires that supply juice to break apart the problem molecules," Devlin said. "The clean water then continues to flow through the barrier and comes out the other side."

Devlin's grant will pay him to help ensure that the technology works as well as it can. He wants to learn how the iron works and apply that knowledge to design better barriers.

One concern is that the steel may not always react quickly enough. Devlin said that it typically takes the water about ten days to push a contaminant molecule through a PRB. If the steel reacts too slowly, some of the contaminants may survive their ten-day trip and leak out the other side of the barrier.

Devlin will also investigate ways to keep PRBs from clogging. He said that things like rust and bacteria can stop up a PRB and prevent water from flowing through it. Instead, contaminated water may flow around the sides.

Devlin will investigate the potential for clogging by rust and a mineral called magnetite, which forms when iron contacts water.

Michael Campbell is a journalism student at

The University of Kansas. He can be reached

by e-mail at campbell@ittc.ku.edu.

See GEOLOGIST, page 5C

Geologist: Clay helps clean up ground

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