Abstract: Variation in Selenium Reduction by Naturally-Occurring Microorganisms
ADAMS, D. JACK, TIM PICKETT, and JENNIFER MURCHISON Center for Bioremediation, Weber State University
For every barrel of oil produced, the petroleum industry generates an average of eight to 10 barrels of wastewater, amounting to 11.7 billion barrels of wastewater generated in the United States annually, according to EPA reports. Selenium, naturally present in some soils and oil-bearing strata, is released from crude oil to process water during portions of the refining process. The wastewaters generated contain both hydrocarbons and inorganics presenting a potential environment threat and increasing oil production costs. EPA selenium water quality discharge objectives have been set at 50 parts per billion for fresh water and 71 parts per billion for salt water. Previously developed selenium removal bioprocesses cannot consistently meet these criteria and conventional technologies are not cost-effective for large water volumes. This study shows that naturally-occurring microorganisms and microbial consortia possess a range of selenium reducing capabilities and differ considerably in their effective reduction of selenate and selenite. This variation is compounded by further variation in the environmental conditions required for effective selenium reduction/removal. Applicability of selected microbes and microbial consortia to a recently developed, cost-effective selenium removal bioprocess for petroleum wastewaters will be addressed.
AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah