Lower Cost Produced Water Treatment in the Gulf Coast Region: Investigation of Biotreatment Methods

Abstract

Lower Cost Produced Water Treatment in the Gulf Coast Region: Investigation of Biotreatment Methods D.G. Sholtes, SPE, BDM Federal, Inc., M.A. Young, SPE, M.A. Young, Inc. - J.S. Jones, SPE, BDM Petroleum Technologies Copyright 1997, Society of Petroleum Engineers, Inc. Abstract Direct discharge of oil field produced waters to surface waters has been a widely used disposal method in the Gulf Coast Region since regional production began. Produced water from oil and gas production operations has received increasing scrutiny in recent years relative to the potential impacts on surrounding, often sensitive habitats due to the tremendous volume of waste water generated and the specific constituents typically present. The effluent limitation guidelines promulgated by the EPA under the authority of the Clean Water Act are limiting produced water discharges to the surface waters of the United States. For coastal Louisiana and Texas, the future of produced water discharges seems forbidding. Zero discharge limits will dramatically increase the operating costs for produced water disposal in the Gulf Coast Region and significantly limit the economic life of producing wells and fields. The increasing reliance of the United States on foreign oil compels the industry and government to research and develop cost effective environmental compliance technologies for produced water disposal. BDM-Oklahoma is investigating the feasibility of biological treatment methods for the treatment of produced waters in an effort to prove that discharged effluent can meet the increasingly stringent effluent limitations for the Gulf Coast Region. Biological treatment technologies are being developed for the treatment of oil field produced waters. Two biological treatment technologies were investigated under this study and the promising results are summarized in this paper. A bench treatability study was conducted on an organic material in a packed-bed upflow reactor. In addition, results from a Gas Research Institute study on a second biological treatment method which utilizes a granular activated carbon fluidized bed reactor are presented. This treatment technology has been tested at the pilot and field scale. Introduction The purpose of this study is to identify current and proposed regulatory requirements related to produced water treatment and disposal in the Gulf Coast Region and to identify and demonstrate innovative technologies which could be used for complying with produced water surface disposal requirements. This report presents findings on two biological treatment methods for produced waters in an effort to prove that discharged effluent can be treated to meet increasingly stringent effluent limitations. For the Territorial Seas of Louisiana and Texas and the Outer Continental Shelf (OCS), increasingly stringent discharge limitations will require aggressive treatment technologies for compliance to become cost effective. Biological treatment methods for reducing levels of toxic metals and organics from produced waters by removing free oil and grease, destroying dissolved hydrocarbons, and removing dissolved metals are being developed with the goal of offering cost-effective methods for the treatment of oil field produced water. A bench scale feasibility study was conducted which utilizes an organic matrix coated with a microbial consortium in a packed-bed upflow reactor. A second biological treatment method was evaluated which employs a granular activated fluidized bed reactor treatment technology tested at the pilot scale and at full scale. Both technologies show promise for removal of contaminants to levels which could allow for surface discharge of treated water as an alternative to transport or reinjection. The goal of each technology development effort is to provide a cost-effective technology for treating produced water to allow for surface discharge of treated effluent. Information on the following technologies was provided by the respective research organizations. P. 143^