BIXBY, Okla. (AP) - Soil pulled from horizontal directional drilling at urban construction sites can help your lawn, if used in the right amounts, according to research at Oklahoma State University.
In a first-of-its-kind study, Oklahoma State University is examining the use of this construction byproduct as a land application.
So far Josh Daniels is encouraged by the results. Daniels, a research assistant and graduate student seeking a master’s degree, started his work in the fall of 2013. He expects to start writing his results next spring, The Journal Record reported (http://bit.ly/ZHdPa4 ).
The research was recently shared during a field day at the Oklahoma State University Vegetable Research Station in a rural area of Bixby. Representatives from about 20 construction contractors were there to learn details about the effects of spreading the urban horizontal directional drilling mud over their property.
The event was sponsored by the Oklahoma State University Division of Agricultural Sciences and Natural Resources, or DASNR.
Contractors routinely drill under roads or buildings to install utilities, fiber-optic cable, sewer lines or water lines. The soil that is brought to the surface must be disposed of properly, said Chad Penn, associate professor of soil and environmental chemistry.
The biggest concern for contractors is how to dispose of the mud, Penn said.
Electrical contractor Brad Ritter said he already spreads the mud on his property to control erosion.
Ritter called the research valuable.
“If it proves that you can use this, it will allow contractors to cut their costs,” Ritter told the group. “I see the biggest challenge is convincing people it is not harmful.”
Last year, Daniels began collecting samples of mud resulting from the horizontal directional drilling, or HDD. The samples came from across the United States. So far, Daniels has 58 samples from about 25 states. The study has shown the HDD mud is mostly soil and may contain additives such as bentonite, soap and phosphates, polymers and sodium carbonate. Bentonite is an ingredient in cat litter. Sodium carbonate is baking soda and controls the acidity of the drilling fluid. The substances in the samples were added by contractors to water that was used to aid drilling, Penn said. Other substances found from the samples included salts, metals and plant nutrients.
Richard Levings applauded the research. He is director of product management with American Augers, a segment of Charles Machine Works Inc.
“If you say it is made up of clay and phosphates, all these things are beneficial to the soil,” Levings said. “People pay to have phosphates spread over their yard.”
While the term horizontal directional drilling mud sounds similar to the substance used in energy exploration and production, these urban operations have nothing to do with the oil or gas sector, Penn said.
In Daniels’ study, the slurry mixture was spread over bare and grass-covered plots at five applications rates. A control plot received no mud.
After 60 days, the bare plots had Bermuda grass growth equal to plots that received no mud, but a 20-tons-per-acre application increased the Bermuda grass cover. Only the plot with 100 tons per acre had less coverage, Daniels said.
“No research like this has been conducted,” said Daniels. “People hear `drilling mud’ and automatically think oil and gas, and this is not the case. There needs to be a study showing this mud can be useful.”
Tests show that the mud helps the soil retain moisture, but the benefits of an application are short-lived, Penn said.
Ditch Witch sponsored the research, spokeswoman Jeri Lamerton said. The cash amount was not available.
“This is an independent study by OSU, we just funded it,” Lamerton said. “This study will benefit the industry.”