[USA] An oil-field waste product that poses environmental challenges and is linked to earthquakes could become a valuable economic resource if the efforts of Oklahoma State University researchers are successful.
Biosystems and agricultural engineering professor Nurhan Dunford and her team have spent much of the past five years developing strains of algae that can be turned into biofuels and feedstocks for food or medicines. The researchers also are using the algae to clean water contaminated by agriculture and oil production.
“Unfortunately, both animal production and hydraulic fracturing operations utilize large volumes of fresh water and generate wastewater that is putting a lot of pressure on our limited fresh water resources and creating huge problems in terms of wastewater disposal and human and environmental safety,” Dunford said. “Our algae research addresses these concerns and problems.”
The researchers are studying strains of algae native to Oklahoma in hopes of finding the best algae and strongest mix of nutrients to clean oil-field wastewater. The researchers are studying both flowback water — mostly freshwater mixed with small amounts of chemicals and sand used for hydraulic fracturing — and produced water. Produced water refers to ancient ocean remnants that are recovered from deep below the surface, along with oil and natural gas. Produced water typically is many times saltier than the ocean and contains minerals and chemicals, along with mixtures of oil and other hydrocarbons.
Large quantities of produced water are pumped underground in saltwater disposal wells through a process that researchers and regulators say are causing or contributing to the ongoing earthquake swarm. Dunford hopes her research will lead to other uses for the water.
“Successful completion of this project will result in technologies that can be licensed to local entrepreneurs and/or businesses for wastewater treatment and bioproduct manufacturing,” she said.
The algae is designed to feed on nitrogen and oil remnants in the produced water.
“When the algae grow, hydrocarbons and other contaminations are removed,” visiting scientist Giovanni Lutzu said. “The biomass can then be used as a feedstock for many uses. Our purpose is to clean up the wastewater, produce biomass and use the biomass for biofuel.”
Lutzu joined the project last year after studying the use of algae in cleaning up food waste in China and animal waste in Italy.
At OSU, the effort so far has shown strong results in the controlled lab environment, where researchers are determining which kinds of algae are most suitable for cleaning wastewater, Dunford said. The team has shown the Oklahoma algae can grow in wastewater and now is trying to find the best algae strains and conditions.
“So far we have been running our tests in the lab and in a greenhouse under controlled conditions,” Dunford said. “For microalgae cultivation to be commercially viable, it needs to be done in large outdoor ponds. So we need to scale up the system. … We have been focusing on the characterization and utilization of algal biomass produced in wastewater. Our future work will put more emphasis on water quality before and after algae growth.”
Oil-field wastewater recycling is a critical part of a statewide effort to both find new sources of usable water and to reduce the disposal of wastewater throughout the sate. Gov. Mary Fallin in December created the Water for 2060 Produced Water Working Group, which she tasked with finding better options for the produced water.
“We are focused on doing everything possible to make more reuse and recycling of produced water a reality in Oklahoma,” said J.D. Strong, director of the Oklahoma Water Resources Board and chairman of the group.
The new group has held one meeting and still is organizing, but Strong said the OSU algae study is a “perfect example” of the opportunities available for the use of a product that mostly is thrown away.
“It appears there is no shortage of technologies and processes out there that can take just about any kind of water, including the worst-imaginable water, and turn it into usable water,” Strong said. “The big challenge is who can do it in a way that’s feasible in terms of handling the volumes we’re talking about and at a cost that is reasonable for the oil and gas industry to bear.”
View original article at: Oklahoma State University study could bring new uses for oil-field wastewater