Cleanup at Landwell Co. development site nearly half completed

By Jeremy Twitchell

Thursday, April 9, 2009 | 8:46 p.m.

The daunting task of moving roughly 2.2 million cubic yards of contaminated soil on former industrial land near Boulder Highway and Lake Mead Parkway in Henderson is approaching the halfway point, project managers reported Thursday.

Basic Remediation Co. is removing the dirt from collection pools that held industrial runoff from chemical manufacturers on the other side of Boulder Highway so that parent company Landwell Co. can develop a 2,200-acre mixed-use development — known as Cadence — at a future, undetermined date.

“It is still anticipated that the first phase will begin construction when the economy turns around, and once remediation is complete, infrastructure improvements should commence on the site,” Landwell CEO Mark Paris said in a statement.

Since work began in October, crews have removed 875,000 cubic yards of contaminated soil and trucked it across Boulder Highway to a triple-lined landfill, in accordance with a detailed remediation plan approved and regulated by the Nevada Department of Environmental Protection.

Dr. Ron Sahu, director of environmental services for Basic Remediation, said the soil removal could be finished as soon as November, but testing to confirm the site is clean and any follow-up work that needs to be done could last up to an additional year.

Though the collection pools represent only a portion of the 2,200-acre site, Sahu said, Basic Remediation is testing and, if necessary, cleaning up the entire site.

“Our goal here is the highest level of clean, which will support residential housing,” Sahu said.

The project area has been split into 15 sub-areas, two of which NDEP has certified as clean. Six more have samples under testing.

Achieving the “no further action” approval of NDEP can require several rounds of testing — one completed area required three rounds of tests (with additional remediation between each round) and one of the pending areas is in its fourth round of testing.

Sahu said the major challenge in the past three months has been on the west side of Boulder Highway, on the landfill site. One part of the landfill had five long, wide trenches dug into it during the 1960s that were used for improper waste disposal, Sahu said. Crews have found office, construction, yard and even chemical wastes in the trenches and have had to move carefully.

“They are a little challenging because we don’t know what we’ll find,” Sahu said. “None of the waste placement was documented very well. … It was a learning experience for the first few days and weeks because we found some materials that like to burn spontaneously.”

Those materials, Sahu said, burn when they come in contact with oxygen and cannot be extinguished with water, so the plan calls for crews to uncover them, allow them to burn themselves out, then move them into parts of the landfill that have been lined and properly prepared.

Sahu said air quality is closely monitored when the substances burn, as it is around the work site.

When the trenches are clear — Sahu said the task is about 40 percent complete — they will be refilled, lined and become part of the landfill.

Groundwater monitoring wells have been set up around the landfill and will be in place for 30 years after the landfill’s completion, according to the NDEP.

Sahu said the highlight of the project has been its safety record — there have been no injuries and the only accident has been a minor traffic accident between a work truck from the site and a passenger car on Boulder Highway.

“Our measure of success is not just how much dirt we move,” Sahu said.

Brian Rakvica, special projects supervisor with NDEP, said he has received a few anonymous complaints about the project, but none of them have held up under investigation.

“(Basic Remediation) has been an excellent partner, responsive to everything we’ve asked of them,” Rakvica said.

Sahu said in addition to the soil cleanup, Basic Remediation is monitoring groundwater throughout the site to determine what, if any, contaminants are present that would require additional cleanup efforts. Two companies that once created ammonium perchlorate in Henderson, Tronox and American Pacific, are already responsible for removing ammonium perchlorate from the groundwater in the area.

Sahu said he hopes to have an idea of what additional contaminants are present and how they are making their way into the groundwater by the end of the year, so that Basic Remediation can formulate a groundwater cleanup plan.