By Thomas Guengerich
LOVINGTON, N.M., Nov. 12, 2008 – Lea County and New Mexico Tech are partnering on a ground-breaking new Department of Energy grant to clean and recycle produced water from the oilfields of southeastern New Mexico.
The two-year grant to Lea County totals $1.432 million. The Lea County Commission approved a $1.3 million subcontract between the County and New Mexico Tech at the Board of County Commissioners meeting Friday, Nov. 7.
Scientists at the university in Socorro will develop a multi-step system to desalinate and further treat produced water. Lea County Commission Chairman Gary Schubert said the goal is to develop new technology that can be commercialized for a wide variety of uses. Some possible uses of the cleaned water include watering livestock, irrigating plants and controlling dust on unpaved roads, he said.
Tech Vice President of Research Dr. Van Romero said the oil and gas industry in southeast New Mexico produces about 400 million barrels of water every year. Most of it is deposited in evaporation ponds because it is not considered usable by humans, or for animals or agriculture.
“We hope this will enable entrepreneurs in Lea County to team with the university and other partners to build new businesses here in Lea County and elsewhere,” Schubert said.
The first year will spent on research. By the end of the second year, mechanical engineering professor Dr. Ashok Kumar Ghosh expects to deliver a system that can process 1,000 gallons per day. The project will employ one post-doctoral student, 3 or 4 graduate students and up to 10 undergraduate students.
Ghosh – who is heading up the research phase of the project – said produced water in southeastern New Mexico contains an average of 212,000 parts per million of dissolved solids, making it less than 80 percent H2O. By contrast, he said, ocean water contains only 3 percent salt and other solids.
The grant, also referred to as a “cell membrane” grant, will be used to search for a cost-effective method of converting the solids-heavy produced water to a more usable state. Scientists at Tech will examine several methods of reducing the particulate matter in brackish water so it can be used for irrigation and wildlife, among other things.
The grant also includes funding to establish a vocational training program at New Mexico Junior College in Hobbs. Tech will work with junior college instructors to develop curriculum to train the technicians who can install, operate and maintain the systems after the project becomes operational.
“Many people have tried this, but there’s such a high level of total dissolved solids that it’s very difficult to find a cost-effective method,” Ghosh said.
The term “cell membrane” comes from a treatment process employing forward osmosis, Ghosh said. This process uses a “draw solution” to push water through a membrane, filtering the solids from the water. Currently available membranes are made of advanced polymers.
The proposal includes two distinct processes: pre-treatment and treatment. Pre-treatment, will remove oil and grease. The treatment process will remove other elements, like salt, chloride and calcium.
To remove the petroleum products – benzene, toluene and xylene – Ghosh has two prime methods of pre-treatment that he will examine. Recent research has found biological organisms that eat petroleum. Biology professor Dr. Rebecca Reiss, through Tech’s partnership with the National Genome Research Center in Santa Fe, will examine the genetic make-up of bioagents that thrive in petroleum-rich environments. Once the microbes do their job, the brackish water would then be filtered to remove the biological agents. Ghosh will also test a zeolite-filtration system developed and patented by Tech hydrology professor Dr. Rob Bowman.
The second step – the treatment process – will employ forward osmosis, a recently-developed method that uses a “draw solution” to force water through a nano-membrane, or what Ghosh calls a molecular sieve.
“We’ll look at the market and test the available membranes,” Ghosh said. “We might have to fine-tune it a bit or design a new membrane and ask the manufacturers to make one.”
Yale research into forward osmosis has found that the process is effective at temperatures as low as 40C, or 100F. Ghosh said he might find that the ideal temperature might be higher, which would increase the cost of forward osmosis.
“Some of these methods are more effective at high temperatures,” Ghosh said. “We would try to generate the heat by using renewable sources – wind and photovoltaics. Hobbs and Carlsbad have plenty of sunshine and wind year-round. Eventually, we would want to come up with a process that generates power from renewables to give us better performance and cost efficiency.”
– NMT –