Comparative assessment of a biofilter, a biotrickling filter and a hollow fiber membrane bioreactor for odor treatment in wastewater treatment plants

A low abatement efficiency for the hydrophobic fraction of odorous emissions and a high footprint are often pointed out as the major drawbacks of conventional biotechnologies for odor treatment. In this work, two conventional biotechnologies (a compost-based biofilter, BF, and a biotrickling filter, BTF), and a hollow-fiber membrane bioreactor (HF-MBR) were comparatively evaluated in terms of odor abatement potential and pressure drop (AP) at empty bed residence times (EBRTs) ranging from 4 to 84 s, during the treatment of methylmercaptan, toluene, alpha-pinene and hexane at trace level concentrations (0.75 4.9 mg m(-3)). High removal efficiencies (RE > 90% regardless of the air pollutant) were recorded in the BF at EBRTs >= 8 s, although the high AP across the packed bed limited its cost-effective operation to EBRTs > 19s. A complete methyl-mercaptan, toluene and alphapinene removal was recorded in the BTF at EBRTs > 4 s and AP lower than 33 mmH(2)O (similar to 611 Pa m(bed)(-1)), whereas slightly lower REs were observed for hexane (similar to 88%). The HF-MBR completely removed methyl-mercaptan and toluene at all EBRTs tested, but exhibited an unstable alpha-pinene removal performance as a reSult of biomass accumulation and a low hexane abatement efficiency. Thus, a periodical membrane-cleaning procedure was required to ensure a steady abatement performance. Finally, a high bacterial diversity was observed in the three bioreactors in spite of the low carbon source spectrum present in the air emission. (C) 2013 Elsevier Ltd. All rights reserved.