Clemson Researchers Receive $800,000 to Clean Toxic Water from Oil, Gas Drilling
February 25, 2009
CLEMSON, SC — February 25, 2009 – Two Clemson University scientists were awarded more than $800,000 to find economical and environmentally sensible ways to treat what oilmen call “produced or co-produced water”: billions of gallons of contaminated water that come out of the ground during oil and natural gas production.
Their work may help the nation achieve energy self-sufficiency and environmental sustainability.
Geologist Jim Castle and environmental toxicologist John Rodgers are developing constructed wetland systems to treat the contaminated water for reuse. The research funding includes $689,500 from the U.S. Department of Energy and $120,000 from Chevron of Houston, Texas.
The treatment of produced water is a major cost of obtaining oil and gas. The water contains salts, oil and grease and chemical additives used in drilling and well operations. Wells may start out producing little water, but eventually many produce more water than oil. In 1993, for instance, 1.09 trillion gallons of produced water were generated — enough water to flow over Niagara Falls for nine days, according to a U.S. Geological Survey fact sheet.
Department of Energy experts say that “co-produced water comprises 98 percent of all waste generated by U.S. oil and natural gas operations. Handling and disposal of this water is the single greatest environmental impediment to natural gas and oil exploration and production.”
Environmentalists have referred to wetlands as nature’s kidneys. Much interest has developed in using constructed wetlands to remove contaminants from water. Current approaches for treating produced water are costly, especially considering the amount of water produced and energy requirements, and some cannot meet new water-quality standards. The cost of treatment using constructed wetland systems has proven to be consistently lower than alternative technologies for treatment, Castle said.
Castle, a professor in the environmental engineering and earth sciences department, and Rodgers, a professor in forestry and natural resources, have developed similar constructed wetlands for the energy industry, such as treating water used in coal-burning power facilities.
“Development of low-cost methods to handle the large volumes of produced water has the potential to increase oil and gas production in existing areas and to open new areas,” said Rodgers. “Constructed wetlands can be an effective and low-cost method of treating the produced waters that also allow the water to be reused.”
In addition to reducing environmental risks, constructed wetland treatment systems generate treated water reusable for many purposes, including irrigation, livestock watering, cooling-tower water, municipal water use, domestic use, treated sewage discharge dilution and support of critical aquatic life and wildlife.
Constructed wetlands typically have four parts: the liner, distribution media, plants and an underdrain system. The liner keeps the contaminated water in and groundwater out of the system. The distribution system spreads the wastewater across the wetland. Plants used often are cattails, but other species include bulrushes, reeds and sedges. Plants need to grow and flourish in the system for it to operate at maximum efficiency. The underdrain system moves treated water out of the wetland and controls the level.
