title: A two-phase partitioning airlift bioreactor for the treatment of BTEX contaminated gases.
abstract: This investigation characterizes a novel 11 L airlift two-phase partitioning bioreactor (TPPB) for the treatment of gases contaminated with a mixture of benzene, toluene, ethylbenzene, and o-xylene (BTEX). The application of the TPPB technology in an airlift bioreactor configuration provides a novel technology that reduces energy intensity relative to traditional stirred tank TPPB configurations. The addition of a solid second phase of silicone rubber beads (10%, v/v) or of a liquid second phase of silicone oil (10%, v/v) resulted in enhanced performance of the airlift bioreactor relative to the single phase case, with 20% more BTEX being removed from the gas phase during an imposed transient loading. During a 4 h loading step change of three times the nominal loading (60 g m(-3) h(-1)), overall removal efficiencies for the airlift TPPBs containing a liquid or solid phase remained above 75%, whereas the single phase airlift had an overall removal efficiency of 47.1%. The airlift TPPB containing a silicone rubber second phase was further characterized by testing performance during steady-state operation over a range of loadings and inlet gas flow rates in the form of a 3(2) factorial experimental design. Optimal operating conditions that avoid oxygen limitations and that still have a slow enough gas flow rate for sufficient BTEX transfer from the gas phase to the working volume are identified. The novel solid-liquid airlift TPPB reduces energy inputs relative to stirred tank designs while being able to eliminate large amounts of BTEX during both steady-state and fluctuating loading conditions.
authors.affiliation: Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada.
authors.forename: Jennifer V
authors.initials: JV
authors.lastname: Littlejohns
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Daugulis
mesh_terms: D000389:Air Conditioning / Q000379:methods*; D000393:Air Pollutants / Q000378:metabolism*; D001554:Benzene / Q000378:metabolism; D001555:Benzene Derivatives / Q000378:metabolism; D019149:Bioreactors; D005740:Gases / Q000737:chemistry*; D006844:Hydrocarbons, Cyclic / Q000378:metabolism*; D011549:Pseudomonas / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014050:Toluene / Q000378:metabolism; D014992:Xylenes / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D001555:Benzene Derivatives; D005740:Gases; D006844:Hydrocarbons, Cyclic; D014992:Xylenes; D014050:Toluene; D001554:Benzene; C004912:ethylbenzene; C026114:2-xylene