At New York State Superfund Site, UB Engineers Help Test 'green' Treatments For Hazardous Waste

BUFFALO, N.Y. -- Environmental engineers at the University at Buffalo are playing a leading role in one of New York State's first efforts to clean up a state Superfund site using bioremediation, an environmentally friendly and cost-effective technology.

If the demonstration project proves successful at the Sweden 3-Chapman site in Sweden, south of Brockport, it could lead to much wider use of the technology in the state and a lower bill for cleaning up hazardous-waste sites.

Bioremediation is the use of indigenous microorganisms, typically bacteria, that occur in nature, to render hazardous waste harmless by converting it into common minerals.

The $1.1 million project is the first in the U.S. to compare three different bioremediation technologies at the same site. The idea is to see which technologies are most successful in remediating the hazardous waste.

Through support provided by the New York State Legislature and spearheaded by Sen. John B. Daly (R-Lockport), UB's New York State Center for Hazardous Waste Management is contributing about $120,000 to the pilot project, a cooperative effort between the center, the New York State Department of Environmental Conservation (DEC) and the Environmental Protection Agency.

"Bioremediation has been touted as a cost-effective alternative to conventional technologies, such as incineration," said A. Scott Weber, Ph.D., associate professor of civil engineering at UB, and principal investigator on the demonstration project. "But its application has been limited by a general lack of process understanding and poorly documented field testing."

The protocol for evaluating bioremediation in the field was developed by a panel led by Ralph Rumer, Sc.D., the center's executive director. When the DEC solicited bids from companies to demonstrate bioremediation at the site, companies were required to submit plans closely following those rules.

The companies that won the bidding are demonstrating techniques conducted both in situ, where bioremediation is done in the ground, and ex situ, where the soil is excavated, treated and then put back into the ground on-site.

• An in situ bioventing process, where blowers circulate through the soil nutrients that stimulate the growth of bacteria, which attack and break down pollutants. (R.E. Wright and Associates, Middletown, Pa.)

• An in situ process in which biodegradation is increased by the delivery of nutrients to bacteria in the soil through the recirculation of groundwater. (Environmental Laboratories, New Haven, Conn.)

• An ex situ biovault process that involves excavating the soil, encapsulating it in a large plastic liner, adding nutrients to it to stimulate bacterial growth, and then returning the treated soil to the site. (ENSR Consulting and Engineering and Larsen Engineers, Houston, Texas and Rochester, N.Y.)

"As far as 'green' techniques go, bioremediation uses indigenous microorganisms found in nature to convert hazardous chemicals to their mineral form and it uses very little energy to do it," Weber said. "It doesn't get much better than that."

The end products of bioremediation are common minerals, carbon dioxide and biomass (humus), which require no further processing.

Weber and graduate students Leslie Jansen, Don Jacobs and Peter Merlo are working at the site, trying to determine the amount of contamination in soil before and after bioremediation. They are collecting air, soil and water samples, which will be sent to an EPA-approved laboratory where they will be tested for volatile organic compounds, bacteria, nutrients and other components.

The sampling project will help determine the level of contamination after bioremediation, what degree of degradation has been attained and what role biodegradation is playing in the breaking down of hazardous waste.

"Historically, New York State has not selected bioremediation as a technology for cleaning up Superfund sites," Weber said. "There has been excellent progress in understanding it through laboratory studies, but there isn't a lot of field experience with compounds other than petroleum-based hydrocarbons."

The compounds to be bioremediated at the Sweden site are chlorinated and nonchlorinated solvents. The site reportedly was used to dispose of construction and demolition debris.

What complicates the project, Weber said, is the fact that even within a particular site, conditions can vary significantly.

"There are so many unknowns," he said. "There are different soil types, differences in the availability of nutrients, and variations in the locations of the water table, even between areas at the same site."

Those variations require that soil samples from many locations at the site be tested.