VATIS UPDATE Article

A pilot facility at the Garfield County landfill at the base of the Roan Plateau near Rulison, the United States, is using microbes to clean petroleum-contaminated soil. The facility is the first of its kind in Colorado, and unique for a public facility in terms of the blend of technologies it incorporates. It can accept waste mainly coming from the oil and gas industry and clean it to a point that the landfill will be able to use the treated soil as a cover material over waste. That will prove to be a valuable byproduct of the process because soil is hard to come by at the facility.

The treatment concept arose during strategic solid waste management planning undertaken by the county in 2014. Petroleum-contaminated soil (PCS), consists of materials such as cuttings produced during well drilling, soil cleaned up in spills, and so-called “filter cakes” produced in gas-processing operations. “The treatment concept grew out of the fact that the state Air Pollution Control Division, stopped the use of untreated PCS as landfill cover,” said Gary Webber, at Northwest Colorado Consultants, Inc., the United States.

One of the technologies is what’s called a biopile, which involves mixing the contaminated soil with a bulking agent like wood chips, nutrients such as nitrogen and phosphorous, and sometimes a microbial “inoculum” such as manure. The mixture is kept moist and is piled on perforated pipes to allow aeration, and the microbes biodegrade the hydrocarbons in the soil. But biopiles are meant to be used in a onetime process in which the pile is removed once it’s done and the project is considered done.