DIISOPROPANOLAMINE BIODEGRADATION POTENTIAL AT SOUR GAS PLANTS

The potential for aerobic and anaerobic biodegradation of a sour gas t reatment chemical, diisopropanolamine (DIPA), was studied using contam inated aquifer materials from three sour gas treatment sites in wester n Canada. DIPA was found to be readily consumed under aerobic conditio ns at 8 degrees C and 28 degrees C in shake flask cultures incubated w ith aquifer material from each of the sites, and this removal was char acterized by first-order kinetics. In addition, DIPA biodegradation wa s found to occur under nitrate-, Mn(IV)-, and Fe(III)-reducing conditi ons at 28 degrees C, and in some cases at 8 degrees C, in laboratory m icrocosms. DIPA loss corresponded to consumption of nitrate, and produ ction of Mn(II) and Fe(II) in viable microcosms compared to correspond ing sterile controls. A threshold DIPA concentration near 40 mg/L was observed in the anaerobic microcosms. This report provides the first e vidence that DIPA is biodegraded under anaerobic conditions, and our d ata suggest that biodegradation may contribute to DIPA attenuation und er aerobic and anaerobic conditions in aquifers contaminated with this sour gas treatment chemical.