Noranda Cleanup Will Take Ten Years Or More—

Firm Comes To Grips With Its Legacy Of Industrial Pollution

By Andrew Gorosko

An industrial firm is conducting a decadelong environmental cleanup project designed to minimize by 2020 residual chemical pollution at its Prospect Drive site and also at an adjacent property near Mile Hill Road South.

In 1987, the state Department of Environmental Protection (DEP), ordered Noranda Metal Industries to study the nature and extent of chemical contamination at its Prospect Drive manufacturing site and also to take appropriate steps to clean up the property.

In 1989 and 1990, the firm did some initial cleanup work. In 2004, it started an in-depth study of the contamination in seeking to resolve the problem.

Workers supervised by an engineering company are proceeding on two fronts to clean up the longstanding subterranean pollution problem caused when Noranda, which formerly had a factory off Prospect Drive known as Noranda Forge Fin, inadvertently released significant amounts of a toxic degreasing solvent at its property after the solvent was used in its manufacturing processes. The chemical’s release thus created a “brownfield,” or contaminated industrial site.

Workers are laboring to clean up the residual chemical contamination at Noranda’s 12-acre site at 11 Prospect Drive. Prospect Drive is a dead-end street extending eastward from South Main Street, just south of Highland Plaza.

An adjacent contaminated site amid wetlands, where Noranda’s environmental cleanup work also is underway, has access from 40-50 Mile Hill Road South. The wetlands there are located along an unnamed tributary of the Pootatuck River.

A staging area has been built for construction equipment on the west side of the residential Mile Hill Road South. Samonewt, LLC, owns the land where that cleanup work is underway.

In May 1987, the DEP issued Noranda the consent order to investigate the nature and extent of groundwater, surface water, and soil contamination that resulted from the storage, handling, and disposal of chemical waste at Noranda’s Forge Fin Division, which manufactured industrial products including copper tubing. Through that pact, Noranda was ordered by DEP to eliminate or minimize the chemical contamination.

DEP Analyst

DEP Environmental Analyst III Maurice Hamel, a geologist, explained that the chronic release of the toxic solvent trichloroethylene (TCE) occurred in the 1950s and 1960s through a hole positioned in the floor of the Noranda factory, which led to an underlying dry well. TCE is a volatile organic compound similar to dry cleaning fluid.

The industrial use of the Noranda site ended about 1990.

The Noranda Forge Fin site is in the vicinity of the Pootatuck Aquifer, which has been designated as the town’s sole-source aquifer by the US Environmental Protection Agency (EPA).

Following the DEP’s order to Noranda to resolve the pollution problem, the horizontal and the vertical extent of a residual subterranean TCE pollution “plume,” or pattern, was thoroughly investigated.

That study indicated that the TCE that had contaminated groundwater on the factory site also was draining down to a nearby Mile Hill Road South wetland, which in turn is drained by a stream.

“Domestic [water supply] wells on the [east] side of the wetland are tested on a regular basis showing no detectable [TCE] concentrations,” Mr Hamel wrote in an August 2009 environmental report. The wells for houses are on the east side of Mile Hill Road South, across that street from the contaminated wetland.

“A [residential] subdivision for several lots on the far fringe of the wetlands has been proposed and was rejected by the town because of these unresolved water quality questions,” Mr Hamel wrote.

In January 2008, for the second time, the Newtown Planning and Zoning Commission (P&Z) rejected a proposed four-lot residential subdivision on the Samonewt property, citing potential health hazards at that site posed by the presence of chemically contaminated groundwater in the area.

P&Z members turned down the home construction application submitted by Stratford developer Jack Samowitz for the 40-acre site at 40-50 Mile Hill Road South, which is on the west side of that street.

P&Z members found that the project did not comply with the subdivision regulations, which require that a site contain land that can be used for construction without a danger to the public health, safety, or welfare. An unknown risk to public health exists at the site, the P&Z added.

Also, P&Z members said it is unknown whether home construction on the Samonewt site would cause the existing subterranean TCE pollution plume in that area to spread, possibly contaminating existing domestic water wells.

In their rejection of the subdivision proposal, P&Z members decided that the presence of contaminated groundwater in that area may pose future water well contamination hazards to the residents of a new subdivision, as well as to the residents of existing homes in the area.

Also, much of land that the developer had proposed donating to the town as open space has subterranean TCE contamination, posing unacceptable potential public health risks, making such open space unacceptable for public use or public ownership, P&Z members decided.

Toxicity Hazards

According to the US Agency for Toxic Substances and Disease Registry (ATSDR), the substance known as TCE is a nonflammable, colorless liquid with a somewhat sweet odor and a sweet, burning taste. It is used mainly as a solvent to remove grease from metal parts, but it is also an ingredient in adhesives, paint removers, typewriter correction fluid, and spot removers. TCE is not thought to occur naturally in the environment. However, it has been found in underground water sources and many surface waters in the US, as a result of the manufacture, use, and disposal of the chemical.

The International Agency for Research on Cancer (IARC) has determined that trichloroethylene is “probably carcinogenic to humans,” according to ATSDR.

As a basic measure to reduce the TCE contamination at its point of origin, workers for the Noranda cleanup project last year excavated and removed the soil lying beneath the former concrete slab where the Noranda factory had stood. The soil was excavated down to the level of the subterranean water table, after which the soil was trucked away for disposal.

After the TCE had been released from the factory, the substance “pooled” underground in the form of a residual subterranean “smear” on the upper surface of some bedrock on the site.

Besides the soil excavation that occurred near the TCE pollution’s point of origin, electrical resistance heating and anaerobic biological decomposition zones will be used to lessen the pollution problem.

The “maximum extent prudent” removal of contaminants from the affected area will minimize the duration of the underground pollution plume, and also will lower the concentration of the contaminants in the groundwater that discharges to a nearby stream and to wetlands, according to Mr Hamel.

Mr Hamel estimated cleanup costs for the Noranda project are likely to exceed $10 million.

In September 2009, after lengthy review, the DEP’s remediation division of its bureau of water protection and land reuse, approved a remedial action plan for the groundwater contamination at the Noranda site and also at the adjacent Samonewt property.

Mr Hamel said it is likely that “hundreds of gallons” of TCE was discarded on the Noranda site in the past after the substance had been used in its metals cleaning process. The powerful solvent was discarded because it had become dirty after its use, he said.

It appears that that the residual underground TCE pollution plume is stable, he said. DEP’s monitoring of domestic well water supplies at homes along Mile Hill Road South has indicated no pollution impact on those wells, Mr Hamel said.

The Mile Hill Road South area is downslope of the Noranda site.

By contrast, the houses along Prospect Drive are upslope of the Noranda property. Prospect Drive is served by a public water supply.

“The state [DEP] is very happy with the [remedial] approach here,” Mr Hamel said of the several ways in which AECOM is seeking to resolve the pollution problem for Noranda.

When the DEP issued the consent order to Noranda in 1987, the cleanup project initially appeared to be a relatively simple matter, but additional study indicated the chemical complexity of the situation and the ensuing methods that would be required for a cleanup, he said.

Besides the physical removal of the most heavily contaminated soils, heat sources will be used to boil off, or volatilize, residual amounts of TCE on the site.

Additionally, a technology known as “bioremediation” will be used in which food-grade vegetable oil will be injected into some drilled wells to foster anaerobic biological decomposition that will lead to the eventual chemical neutralization of the TCE contaminant.

Through past extensive site testing, those people performing the cleanup project are well aware of the location of the contaminants, Mr Hamel said. Through repeated testing at the site, the progress of the cleanup will be measured, he said.

Engineering

Environmental engineer Lucas A. Hellerich, PhD, of AECOM Technology Corporation oversaw the technical design of the cleanup project for the Noranda property and the adjacent Samonewt site. Mr Hellerich is the project manager.

Mr Hellerich explained recently that after the demolition of the concrete slab that formerly held the Noranda factory, about 3,500 cubic yards of contaminated soil from that area was trucked away, resulting in that area being restored to “residential standards” in terms of pollution levels. Clean soil replaced the tainted soil on the site, he said.

The existing pollution plume has been thoroughly delineated through monitoring via a network of wells and has been found to be stable, he said.

The pollution plume has never created pollution conditions in nearby domestic water wells, he said.

Besides DEP’s review, the Noranda cleanup plans have been reviewed and endorsed by the town’s Inland Wetlands Commission (IWC), and by the US Army Corps of Engineers (USACE), he said.

USACE last year approved allowing Noranda to physically disturb 1.6 acres of wetlands as part of the project to install drilled cleansing wells, related structures, and temporary roads to clean the contaminated groundwater.

Rob Sibley, town deputy director of planning and land use, said that Noranda obtained the town wetlands permit that is required to perform such a cleanup project. “This will take years,” he said of the cleanup effort.

Mr Hellerich noted that the remaining remediation project involves two technologies.

A heavily polluted area on the Noranda site holds drilled wells into which electrodes will be placed to heat and then “boil off” contaminated groundwater. A vacuum system is used to recover the contaminants for their removal. The process is known as “electrical resistance heating.”

In the less-polluted areas on the Noranda site and also on the nearby Mile Hill Road South site, food-grade vegetable oil will be injected into the groundwater via drilled wells. Bacterial action, spurred by the presence of the nutrient vegetable oil, would then neutralize the TCE.

Mr Hellerich said he expects that the construction work for the decadelong cleanup process should be completed by late this year or by early 2011. The overall project should be done by 2020.

Mr Hellerich explained that based on the layouts of the two adjacent cleanup areas, workers will not need to travel across the Housatonic Railroad’s rail freight line that runs near Mile Hill Road South.

Subterranean

The overall TCE underground pollution plume covers an area of approximately 15 acres, of which about six acres are on the Noranda site and about nine acres are on the adjacent Samonewt site.

The contamination that occurred on the Noranda site affected subterranean conditions about 20 feet to 40 feet below the ground’s surface, while the off-site pollution near Mile Hill Road South lies approximately 20 feet to 25 feet below the surface, he said.

On the Noranda site, about 100 drilled wells we will be used in cleanup project; “several hundred wells” will be used on the Samonewt site, he said. “We want to make sure we completely treat the contamination,” he said.

The domestic water wells located at homes along Mile Hill Road South have had their water quality under testing for a long period, he noted. “The [pollution] plume is not expanding,” he added. The contamination levels within the pollution plume tend to decrease as the plume extends away from the pollution’s point of origin, he noted.

“They’re [Noranda] fully committed to cleaning up [the contamination[,” he said. When completed, the work will meet DEP’s applicable environmental quality standards, he said.

During the course of scientific testing to establish the type and extent of pollutants present at the Noranda site, checks were made for volatile organic compounds such as TCE, semivolatile organic compounds, metals, polychlorinated biphenyls (PCBs), herbicides, and pesticides, Mr Hellerich said.

The removal of contaminated soils from the site occurred between June and October 2009, he noted. Work to clean up groundwater contamination started last October, he added.

After the cleanup is completed in the wetlands off Mile Hill Road South, the area would be restored with the placement of graded organic soils and with the planting of trees and wetland vegetation.

The cleanup project is a complex process involving multiple disciplines, Mr Hellerich said. The effort involves geology, hydrology, environmental science, civil engineering, microbiology, chemical engineering, and electrical engineering, he said. AECOM has been involved in planning the cleanup project since 2004.

After the property is cleaned, Noranda wants its land to be put back into some productive use, he said.