0115851 Field The objective of this research project is to develop a denitrification bioreactor using H2S as the main electron donor for the simultaneous removal of carbon, nitrogen and sulfur from refinery condensates. The denitrifying bioreactor will be the first stage of a two-stage biological process followed by a nitrification reactor, supplying nitrate via effluent recirculation. Under the joint NSF-CONACyT program, this project forms part of an international collaboration with the Mexican Institute of Petroleum (IMP) and the scientific research funded by this grant will provide a basis for the IMP to develop the proposed technology. This research is needed due to the complex microbial ecology of the system. This research will characterize the microbial consortium in the condensate-fed denitrifying bioreactor. Subsequently, the strategies of controlling the reactor to maximize the removal of sulfide, phenols and nitrogen will be identified. The effect of phenols on the autotrophic denitrification process will be studied. An important aspect of the research will be to control the oxidation of sulfide to form insoluble elemental sulfur, instead of complete oxidation to sulfate, so that it can be physically separated for reuse. ***
