From the September 1, 2005 issue of the SUN
By Nick Wilkinson
SUN Staff Writer
The cleanup of two chemicals from Española's groundwater is expected to take at least 30 years and have several stages.
The cleanup of tetrachloroethene (PCE) and its byproduct, trichloroethene (TCE), is part of a federal Superfund site called the North Railroad Avenue Plume.
Construction of the infrastructure needed for cleanup is fully funded by the federal and state governments. However, only the first stage of the actual cleanup has received funding, Project Manager Steve Jetter said.
Well construction is going on right now, but the first stage of cleanup is not scheduled to start until January 2006. That cleanup will involve the original pollution source area — the area behind Norge Town Laundromat where dry-cleaning chemicals were dumped. A total of eight wells will be installed at the site by the end of October.
Cleaning the North Railroad area will help all other areas because it is the source of all other contamination, Jetter said.
PCE concentrations at North Railroad have been as high as 29,000 micrograms per liter. The federal standard for PCE and TCE in drinking water is five micrograms per liter.
"There is about 30 gallons of pure PCE down there," Jetter said.
There are five different hotspot areas — north of Hunter Street, the plaza, Cook's Hardware, Calle Chavez and the Los Alamos highway intersection with Paseo de Oñate.
PCE has been found as high as 2,500 micrograms per liter at the intersection of Hunter and Espinoza streets.
The contamination extends the deepest under the plaza — to about 260 feet beneath the ground — and covers an area of 600 feet by 400 feet.
"We can't get it all but we're trying to get the hottest areas in the zone," Jetter said.
The Process
For the first seven days of the month-long process to clean up the source site, a solution will be injected into the aquifer to break the PCE out of the sand in the aquifer. The solution works in the same way detergent breaks dirt out of your clothes.
For the next three weeks, the groundwater will then be extracted and treated at an on-site water treatment facility.
"The plan is to pump roughly 500,000 gallons out of the ground," Jetter said.
The treated water will then be discharged into the city wastewater system. The injection and extraction wells will all be hooked together by December so that they can deposit the water they take from the aquifer into the small on-site treatment facilities.
At the source site, two pits for soil — one for contaminated and one for uncontaminated — will be dug and lined with a thick plastic. At the end of the source clean-up, contaminated soil will be sent to a hazardous waste landfill.
The source site will continue to be monitored for at least 10 years, Jetter said.
The next stage, referred to as the hotspot cleanup, involves 30 wells that will inject different substances to stimulate microorganisms in the aquifer. These microscopic bugs eat the offending chemicals, thus breaking them down into non-toxic substances.
"(The bugs) are not active enough," Jetter said. "They need another carbon source or other minerals like phosphorus."
Three different substances — vegetable oil, sodium lactate and whey protein — will be pilot-tested for a year starting in April 2006 to see which one stimulates more microorganic activity.
The last stage is referred to as the bio-curtain and will have roughly 31 alternating wells to inject the substance that wins the stage two competition for stimulation of the microorganisms.
All plans are subject to change, depending on new information and cost overruns, Jetter said.
