Billed as "Remediation 101," the city of Mandan provided 22 years of history on the diesel fuel contamination of the downtown area and, more importantly, a current update of the cleanup effort.

About 50 people attended the meeting held at the city commission room Wednesday evening. Presentations were made by the North Dakota Health Department's Dave Glatt; the remediation's main contractor, Leggette, Brashears and Graham, represented by Tim Kenyon; and city administrator Jim Neubauer.

Glatt detailed how work on the Law Enforcement Center in 1984 led to the discovery of the contamination and the culprit, BNSF Railways. Since that time, various efforts had been made to clean up the fuel, and nearly 600,000 gallons has been pulled from the soil. But two years ago the state and city managed a settlement from BNSF, securing $30.25 million, $24 million of which is earmarked for the contamination cleanup.

The Mandan Remediation Trust was created with its three trustees Glatt, Neubauer and Francis Schwindt. They advertised for a company to clean up, and after narrowing the field to three, interviews led to LBG.

Kenyon said the project has two primary objectives to protect human health and facilitate redevelopment of the downtown.

A multiphase extraction technique is being employed to remove the contamination, which involves the free product in the form of diesel oil, vapor extraction and bioattenuation.

"Diesel fuel is an organic material and essentially rots, giving off methane gas. That's why we have the vapor extraction," Kenyon said. "There are also microbes in the soil which eat the fuel. These bugs don't sleep; they eat and have bug babies. They grow exponentially."

Eventually the process will inject air into the surface of the soil, which will give the microbes more air to breathe, allowing them to eat more diesel fuel and then will be extracted.

The remediation system consists of 280 wells, each with two 4-inch pipes connected to them. One pipe can pull air or push air into the soils, while the other draws product and ground water.

The remediation system is being built in two phases; the first, south of Main Street, was completed this summer. The second, north of Main Street, is under construction. The area between First Street and Main will be completed this year, with the rest to be completed next summer. Once the system is complete, it will take three to five years to complete the work, at an average operation cost of $400,000 a year.

As of Tuesday, the system had drawn 700 gallons of diesel from the ground, 2,000 gallons of water a day, which is treated, seven gallons of solvents, 240 gallons of gas and 40,600 pounds of methane (about a semi load.) It's estimated microbes have eaten about 6,200 gallons of diesel.

The south side project consists of 80 wells and five miles of pipes. The north of Main project will have 200 wells and 14 miles of pipe. The methane gas is burned off and the diesel fuel will be sold when enough is collected. Kenyon said there is no estimate how much diesel fuel remains in the soil.

A total of $6.26 million has been spent on the remediation project and another $3 million has been authorized by the trust to be expended. The total remedial cost, according to Kenyon is an estimated $17 million.

Neubauer said state legislation and local ordinances are in place to allow for the buying and selling of downtown property. Prior to these, banks would not take the risk of lending money on properties in the contaminated area.

The city has spent about $1.1 million in acquiring properties that are beneficial to the remediation effort. Efforts are ongoing as the city attempts to acquire the Ratz and Gartner buildings near the corner of Collins and Main Street, as well as the now closed Buckhorn Bar. The city has had to take legal action to get access to the Ratz building to complete an appraisal of the property. Neubauer said the city was allowed access Tuesday and the appraisal has begun.

The city continues to explore its options for the redevelopment of downtown and is evaluating downtown parking needs. As properties acquired by the city have remediation work completed, they will be put up for lease or sale.

Redevelopment of the property south of Main Street, which is being used for parking and park area is expected to be completed late in September.

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