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New Mexico State University

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NMSU research leads to international clean-up effort

Research conducted in New Mexico State University's civil, agricultural and geological engineering department has made it around the world. A water treatment process developed at NMSU was recently demonstrated in China and officials there liked what they saw - an inexpensive, efficient and safe method for cleaning contaminated water retrieved in the oil drilling process.

Research on the treatment technique was started in 1990 by Gilbert Tellez, who was an NMSU civil engineering master's student at the time. Supported by the Waste-management Education and Research Consortium and civil engineering professor N. Nirmala Khandan, Tellez worked in the laboratory to develop a process using microorganisms to break down contaminants in what the oil industry refers to as "produced water."

When oil is pumped from a well, petroleum-contaminated water comes with it, Khandan explained. The two are sorted by gravity in a tall tank, then crude oil is sent to a refinery. Oil companies are left with produced water, which is highly toxic and carcinogenic after existing in oil formations for millions of years, he said. Produced water often is very saline, or salty, as well.

Since 1980 the oil industry has been required by the Environmental Protection Agency to find a way to dispose of the produced water safely. Simply discharging the water into other surface water supplies killed fish, plants and other organisms, Khandan said. So Tellez and Khandan sought a solution.

They perfected a biological process using bacteria to break down contaminants, turning them into harmless end-products such as water and carbon dioxide. "The resulting water quality exceeds agency standards for discharging safely," Khandan said. "The oil pollutants are gone."

"Use of bacteria for treating wastes is well accepted, but had not been used before for this sort of waste," Khandan said. The researchers used commercially available bacteria, then acclimated them in the lab to the types of waste found in these waters. "The uniqueness of this process is in adapting the organisms to grow in this saline environment while maintaining high removal of the contaminants," he said.

For his doctorate, Tellez engineered the technology and demonstrated the method's feasibility under field conditions at an oil field in Hobbs. Unfortunately, the timing was too late for the EPA, which ruled shortly after Tellez's graduation that re- injection was the produced water disposal method of choice in the United States, Khandan said.

However, through journal articles and a Web site, consultants for the Chinese petroleum industry became interested in the biological treatment process and contacted Khandan. Having found re-injection to be expensive, oil companies in China were looking for an alternative treatment process, Khandan said.

Re-injection, which involves pumping the produced water back into the underground reservoir from which it came, is much more expensive than the NMSU-developed method, Khandan said. "The estimated cost of re-injection is $1.25 per barrel, while the estimated cost for our biological treatment process is 25 cents per barrel."

The Chinese oil industry found that it cost less to discharge the contaminated water and pay the resulting penalties than to re-inject the water, Khandan said. Having studied the results reported by Tellez and Khandan, industry officials decided to test the NMSU-developed biological treatment process as a possible alternative.

Khandan, Tellez, who now works for the EPA in Texas, and Harry Wang, an NMSU civil engineering doctoral student who is Chinese, traveled to northeastern China for two weeks to help implement the process. They treated water generated in the Shengli oil field, southeast of Beijing. It is the second-largest oil field in China, Khandan said.

"In Hobbs, we treated water from only one well - 700 gallons per day," Khandan said. "In China we treated water from 32 wells - 6,000 gallons per day. But keep in mind, they have probably more than 40,000 wells."

Finished a few months ago, the project was a complete success, meeting all standards for discharge, Tellez said. "Now they have the data to proceed with the designs of full scale plants," he said. The industry, which is run by the Chinese government, now is working to raise funds to implement the process at all its oil fields. "We will design a modular system, adding on as additional funding is secured, until we are treating 7 million gallons per day," Tellez said.

"This is a good example of how academic publications can promote lab research to real life applications," Khandan said.