Installation of the third phase of the Mandan remediation system is going much more quickly than anticipated, and the entire system may go online by the end of September.

Tim Kenyon, representing Leggette, Brashears and Graham, the company spearheading cleanup of diesel fuel-contaminated soils in the downtown area, provided a project update at Tuesday's commission meeting.

"We're at a watershed in the project. For the first time in quite a while, you're not seeing any big yellow iron being driven down the streets or pipes being drug around. We're pretty much done installing stuff," Kenyon said.

It was 2005 when contractors started digging up the area south of Main Street, with implementation of the first phase in 2006. It was then decided to install phases two and three, north of Main, over the course of two construction seasons rather than one, which led to a cost saving of about $3 million, Kenyon said.

"By the end of 2007, we were going to have the entire system going," Kenyon said. "But the contractors got done a lot sooner than we expected. The entire remediation system should be going by the end of the third quarter. That's good news."

Work remaining includes the creation of "bump outs" on some of the street corners and reconstruction of First Avenue. Decisions on these projects are being made by the Mandan Remediation Trust.

The contamination recovery numbers as of July 9 show that 10,247 gallons of free product has been recovered. This number hasn't gone up much in the past month since much of the diesel is being sequestered in the system; 31,360 gallons of bioremediation have been recovered; 11,294 gallons of vapor; and 54,986 pounds of methane.

"Since April of 2006, this system has recovered over 50,000 gallons of diesel," Kenyon said. "That is about what the BNSF system did in its last six years."

There are two areas of evidence that show the LBG system is successful. The first is a reduction in the amount of oxygen being used by the biologic activity in the soil, and the second is thickness of diesel on the groundwater table. Both of these are diminishing, according to Kenyon.

(Reach reporter Gordon Weixel at 250-8255 or gordon.weixel@;bismarcktri-bune.com.)