No abstract

iii EXECUTIVE SUMMARYThe main goal of this research was to investigate the feasibility of using a combined physicochemical/biological treatment system to remove the organic constituents present in saline produced water. In order to meet this objective, a physical/chemical adsorption process was developed and two separate biological treatment techniques were investigated. Two previous research projects focused on the development of the surfactant modified zeolite adsorption process (DE-AC26-99BC15221) and development of a vapor phase biofilter (VPB) to treat the regeneration off-gas from the surfactant modified zeolite (SMZ) adsorption system (DE-FC26-02NT15461). In this research, the SMZ/VPB was modified to more effectivtly attenuate peak loads and to maintain stable biodegradation of the BTEX constituents from the produced water. Specifically, a load equalization system was incorporated into the regeneration flow stream. In addition, a membrane bioreactor (MBR) system was tested for its ability to simultaneously remove the aromatic hydrocarbon and carboxylate components from produced water. The specific objectives related to these efforts included the following:(1) Optimize the performance VPBs treating the transient loading expected during SMZ regeneration.■ Evaluate the impact of biofilter operating parameters on process performance under stable operating conditions. ■ Investigate how transient loads affect biofilter performance, and identify an appropriate technology to improve biological treatment performance during the transient regeneration period of an SMZ adsorption system. ■ Examine the merits of a load equalization technology to attenuate peak VOC loads prior to a VPB system. ■ Evaluate the capability of an SMZ/VPB to remove BTEX from produced water in a field trial.(2) Investigate the feasibility of MBR treatment of produced water.■ Evaluate the biodegradation of carboxylates and BTEX constituents from synthetic produced water in a laboratory-scale MBR. ■ Evaluate the capability of an SMZ/MBR system to remove carboxylates and BTEX from produced water in a field trial.Laboratory experiments were conducted to provide a better understanding of each component of the SMZ/VPB and SMZ/MBR process. Laboratory VPB studies were designed to address the issue of influent variability and periodic operation (see DE-FC26-02NT15461). These experiments examined multiple influent loading cycles and variable concentration loadings that simulate air sparging as the regeneration option for the SMZ system. Two pilot studies were conducted at a produced water processing facility near Farmington, New Mexico. The first field test evaluated SMZ adsorption, SMZ Final Technical Report DE-FC26-04NT15546iv regeneration, VPB buffering, and VPB performance, and the second test focused on MBR and SMZ/MBR operation. The design of the field studies were based on the results from the previous field tests and laboratory studies.Both of the biological treatment systems were capable of removing the BTEX constituents in the laboratory and ...

The DDGS dryer vents at corn-derived ethanol production facilities often contain a mixture of odorous and/or potentially hazardous air pollutants including acetaldehyde and formaldehyde. The objective of this study was to investigate the feasibility of utilizing a biofilter system to treat the volatile organic compounds (VOCs) released from the DDGS dryer stack during ethanol production. Single aldehyde elimination capacity experiments indicate that both acetaldehyde and formaldehyde are readily biodegraded in a biofilter at a short contact time of 10 s, although the acetaldehyde removals during the initial start up period were lower than those observed during later operation. A biofilter packed with porous silicate pellets at neutral pH successfully achieved greater than 90% removal of VOC mixtures containing acetaldehyde, formaldehyde, ethanol, and acetic acid. However, extended operation with the four component VOC mixture led to a decline in biofilter pH. At low pH (4.6), acetaldehyde removal declined from 95 to 62% and ethanol removal declined from 90 to 57%. The option of utilizing a water scrubber upstream of the biofilter to remove acetic acid was investigated; it was determined that effective acetic acid removal was possible in a recirculating water scrubber maintained at a pH level above $7, where the rate of removal was controlled by gas phase mass transfer resistance.