FORDS PRAIRIE: City will try to eliminate dangerous chemicals from ground

By Mai Ling Slaughter, The Chronicle, <a href="http://www.chronline.com">The Chronicle</a>, 5/28/99

Rather than dealing with how Centralia's Eshom well was contaminated, city officials are focusing on eliminating dangerous chemicals in the groundwater to bring the well back to life.

The well is located on Fords Prairie. Officials closed it in 1988 after high levels of the contaminant perchlorethene were found in the well, and in the surrounding groundwater.

"That's a huge resource that ought to be available for us," said Utilities Director Richard Southworth.

While in use, the well distributed approximately 1,300 gallons of water a minute.

The Washington Department of Ecology's Tammy Hall, who is overseeing the project, said the contamination most likely came from a solvent used by a dry cleaning company, formerly in the Fords Prairie area at Trailer Village on Harrison Avenue.

Although researchers cannot be absolutely certain the contamination originated there, they did find the solvent at the site - which, Hall said, is rare because PCEs have a tendency to sink.

Because much of Fords Prairie is not within city limits, many of the homes in the area have individual wells that were also contaminated, and some still have unsafe levels of the contaminant.

"There are some (personal) wells above the maximum contamination levels," Southworth said. "This has gone on for a number of years, so I think the people out there know it."

With the help of a $5.2 million grant from the Department of Ecology, city officials hope to connect homes in the contaminated area to the city's water supply, and to have a project under way by the end of 2000 that would suck out the harmful PCEs and decrease the possibility of a water shortage.

Although researchers have learned the approximate groundwater flow in the Fords Prairie area, Southworth said it is difficult to determine in what direction, how deeply and how quickly groundwater travels.

"Groundwater flow is a very imprecise science," he said.

Using their information on the groundwater flow, city officials are proposing building two more large wells downstream from the contaminant to empty the Fords Prairie aquifer more quickly.

The water they pump from the three wells would then be "airstripped" to remove the PCEs, which Southworth described as a way of removing dangerous contaminants, metals and other harmful substances without using chemicals.

Instead, water is pumped down a large cylinder, while air is consecutively blown toward the moving water, forcing the PCEs to stick to plastic balls in the middle of the cylinder.

"The idea is to suck (the contaminant) all in," Southworth said.

Then, the clean water can either be injected into the city's water supply or back into the groundwater.

Southworth said after the aquifer is empty, nature will refill it, although it is uncertain how long it will take until the contaminants are no longer in the area.

City employees plan to test the water frequently until traces of the contaminant have completely diminished.

Problems with the Fords Prairie aquifer are among many plaguing the city's water supply, which is one reason city officials are willing to spend the required $1.3 million to complete the project.

Southworth said officials, along with most water suppliers, find it important to have more than one source of water - such as river water and groundwater - so the city has a backup supply in case the main source breaks.

But a landslide in November 1990 on the Newaukum River's North Fork cut off the city's water supply from the river. The stream was then supplying the city with about 3 million gallons of water a day.

Just more than a year later, one of the city's reservoirs on Seminary Hill collapsed and the other simply leaked itself dry, further diminishing the city's water supply after sending 8 million gallons of water into the underlying neighborhood.

That is when officials decided the contamination levels in the upgraded Eshom well were low enough to justify using the water in an emergency, if combined with other water sources. Because the water is then diluted, Southworth said, the water is within the Department of Ecology's safety standards.

The Eshom well is still used in times of dire need and the reservoirs have been repaired, but knowing how rapidly disasters could threaten the water supply increases the importance of staying one step ahead of Mother Nature.

In light of that, the city is installing a new well with an air stripper next week that - although it will not be nearly as large as the Eshom well - will provide city residents clean water without using chemicals.

The well will be located near the tennis courts in Fort, Borst Park.

Mai Ling Slaughter covers municipal government for The Chronicle.

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