Testing new methods to remove residual coal tar from riverbeds in New York.

For the last 18 months, research engineers and a New York state utility have been using a Hudson River contamination site as a laboratory, testing a new way to remove pollutants from riverbeds, the Times Herald-Record reports.

Coal Tar The carcinogenic compound is a by-product of manufactured gas plants that operated from the 1800s up to the 1950s. Manufactured gas plants burned coal to release its gaseous components, which were fed to pipelines that sent gas to homes and street lamps. Originally produced for illumination, since the gas burned a bright yellow color, the industry shifted to uses such as heating, cooking, refrigeration, and cooling with the advent of electric lighting. After World War II, new housing estates were instead connected to the national electricity distribution grid system, since gas could only be distributed to locations near a gas main. Additionally, the public had begun to regard manufactured gas as smelly, dirty, and dangerous when compared to electricity. Liquefied natural gas replaced manufactured gas by the 1950s, because it was cleaner and cheaper.

During the last week of November, utility workers from Central Hudson Gas & Electric and engineers from the Electric Power Research Institute began removing mattress-sized absorbent panels from the Hudson River at Poughkeepsie, about 80 miles north of New York City.

In place since May 2009, the 75 panels are filled with organo-clay—a mineral that draws oil like a magnet—and are designed to remove coal tar from the riverbed. Typically, the organo-clay is scattered on the site, and the soil is then dredged or excavated. The Poughkeepsie location was too technically challenging for heavy machinery to operate, however, due to river depth and a strong current.

“This is very much a research project,” said Wayne Mancroni, a senior environmental researcher at Central Hudson, to the Times Herald-Record. “We’re uncertain just how well they’re going to do at absorbing the material.”

Coal tar pollution—estimated at $3 billion in remediation costs—is widespread in New York, with similar polluted sites all along the Hudson Valley, as well as rivers off Lake Erie. Coal tar remediation is is the third most expensive clean-up in New York, after PCB removal from the Hudson River and waste removal from Onondaga Lake.

When manufactured gas plants burned coal, released gases were captured and cooled to form natural gas, benzene, and a dozen other compounds. To “crack” coal, high pressure water vapor was used, so manufactured gas plants were often located along waterways that were pumped to cool the machinery.

The waste product from this process was coal tar, a dark-colored, slightly-viscous liquid with the same consistency as cooking oil. Gas plants dumped the tar either into storage tanks that eventually leaked, or into shallow pits near the facility, where some of the tar leached into the soil. From there, it wasn’t far for the tar to travel to settle in nearby river beds.

UTILITIES WITH SITE ORDERS OR AGREEMENTS Central Hudson Gas & Electric: Blue Consolidated Edison of New York and Key Span Energy (Responsible for the former Long Island Lighting Company and Brooklyn Union Gas): Green New York State Electric & Gas: Purple Niagara Mohawk and National Grid: Pink Orange & Rockland Utilities: Yellow UTILITIES IN FINAL NEGOTIATIONS OF SITE AGREEMENTS Rochester Gas & Electric Company Source: Times Herald-Record

The new clean-up technology, including 10,000 square feet of panels removed from the Hudson River, will be tested to determine its effectiveness. If the results are positive, the panels could be reinstalled permanently in Poughkeepsie, and this method could potentially be used at similarly polluted sites throughout the state.

The New York State Department of Environmental Conservation (NYS DEC) estimates that manufactured gas was produced at roughly 300 sites in the state. Recovery programs are in progress or planned for 194 of those, which can be seen in the interactive map below.

Interactive Map: New York Coal Tar Clean-up Sites Click on the points below to learn more about the contamination at that specific site.



View Coal Tar Pollution: New York Clean-up Sites in a larger map. Map © Aubrey Ann Parker/Circle of Blue

There are only 18 sites that qualify as State Superfund sites, and one that has been placed on the U.S. Environmental Protection Agency’s National Priority List. At this time, the NYS DEC has deferred listing a site as a Superfund clean-up if a utility can be held accountable.

**Coal tar is not the same as coal ash, which is a cancer-causing pollutant produced by some coal-fired power plants. Read more about coal ash contamination in Tennessee and Indiana on Circle of Blue.

Source: Times Herald-Record, New York State Department of Environmental Conservation

